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Low Noise Rubidium GNSDO User Manual - NEW!

1. 50 3 6 8 SYNChronization TINTerval FILTer 50 ii 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GPSDO User Manual Labs 3 6 9 SYNChronization IMMEdiate 50 8 6 10SYNChronization FEESstimate 50 3 6 11SYNChronization LOCKed Soe dae wei ot A Dl 3 6 12SYNChronization OUTput 1 PPs RESET lt ON OFF gt pa e Be A al 3 6 13SYNChronization OUTput 1PPs RESET A Lu a 261 3 6 145YNChronization OUTput 1PPS DOMAIN lt CSAC FILTer gt ck et O 3 6 15SYNChronization OUTput 1PPS DOMAIN oe 4 4 61 3 6 16SYNChronization OUTput FILTer lt ON OFF gt 2 2 2 2 51 3 6 17SYNChronization OUTput FILTer HD dw a 4 a eee ie SOT 3 6 18SYNChronization HEAIth eb a a we DA 3 6 19SYNChronization TINT erval THReshold 150 2000 LE 4 em man E 422 3 6 20SYNChronization it an O EOD 3 7 DIAGnostic Subsystem bot a a 458 3 7 1 DIAGnostic ROSCillator EFControl RELative a de Wy gee do ee a ee BOS 3 7 2 DIAGnostic ROSCillator EFControl ABSolute 54 3 7 3 DIAGnostic ROSCillator EFControl ABSolute CSAC 54 3 7 4 DIAGnostic ROSCillator EFControl ABSolute FILTer 54 3 7 5 DlAGnostic LIFetime COUNt 54 3 7 6 DIAGnostic
2. 15 16 A 7 The Power and Ground symbols in Figure 2 5 are for reference only 5V Power on connector J3 is available to drive the LCD display and its backlight and the user may draw a total of 150mA of power from this connector for external circuitry 2 7 7 1 LCD Key The LCD Key is activated by pressing S1 on the PCB see Figure 2 3 or by grounding J1 pin 5 Momentarily activating the key cycles through the LCD display pages described in Section 2 7 7 2 The LCD page can also be selected with the SYSTem LCD PAGE serial SCPI command The last page displayed is remembered in NVRAM and will be shown upon power up 2015 Jackson Labs Technologies Inc 17 Low Noise Rubidium GNSDO tm User Manual J a ck S on Labs Activating the key for 8 seconds initiates the Auto Survey sequence and switches the LCD to the Survey status display page The Auto Survey can also be initiated with the GPS SURVey ONCE SCPI command The unit will automatically enable Position Hold mode after the Auto Survey sequence has ended which typically takes around 1 hour to complete 2 7 7 2 LCD Display Pages The following images show the available LCD display pages Time Date Figure 2 6 This page shows the time date number of tracked Satellites and the lock status PH Position Hold mode AS Auto Survey mode UL Unlocked operation Figure 2 6 Time Date display page e GNSS Position Figure 2 7 This page
3. 40 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs In this Automatic mode the unit will configure the GNSS receiver based on the actual vehicle velocity Please note that in order to switch from the Automotive mode into the first Airborne 1g mode both a vehicle velocity greater than 60 knots as well as a climb descent rate greater than 400 feet per minute are required Alternatively a vehicle velocity of greater than 100 Knots will also initiate a switch into airborne 1g mode Without an appropriate climb descent the unit will remain in Automotive mode unless 100 Knots velocity are breached The following command returns the setting of the GNSS dynamics model GPS DYNAMic MODE The actual state chosen by the firmware for the GNSS receiver based on vehicle velocity can be obtained with the command GPS DYNAMic STATe A value between 0 and 7 is then returned depending on vehicle dynamics The dynamic state is always set to STATIONARY if one of the Position Hold Auto Survey stationary modes is selected using the command GPS TMODE as the Position Hold mode setting overrides any dynamic state user setting Settings will be applied immediately to the GNSS receiver and are stored in Non Volatile memory 3 3 15 GPS DYNAMic STATe This query returns the actual state of the dynamic model chosen by the firmware to be applied to the GNSS receiver depending on vehicle vel
4. 54 3 8 MEASURE Subsystem BA 3 8 1 MEASure TEMPerature 54 3 8 2 MEASure VOLTage DB 3 8 3 MEASure CURRent a BB 3 8 4 MEASure bots gt 3 8 5 MEASure RE 3 9 SYSTEM Subsystem he ae ee amp dla ew amp 2 BD 3 9 1 SYSTem COMMunicate SERial ECHO je ade QUE San eee amp 2 amp 256 3 9 2 SYSTem COMMunicate SERial PROmpt 56 3 9 3 SYSTem COMMunicate SERial BAUD 56 3 9 4 SYSTem FACToryreset ONCE 56 3 9 5 SYSTem ID SN Mao He ES SA Oe wh SM Ra nt 56 3 9 6 SYSTem ID HWrev De ee GS de gt 3 9 7 SYSTem LCD CONTrast 0 1 0 D ie He NN EN go ee oe 4 256 3 9 8 SYSTem LCD CONTrast 56 3 9 9 SYSTem LCD PAGE 0 9 s e s sos rak 57 3 9 10SYSTem LCD PAGE 57 3 9 11SYSTem COMMunicate USB BAUD lt 9600 i 19200 E 38400 57600 ol 115200 gt 57 3 9 12SYSTem COMMunicate USB BAUD 57 3 9 13SYSTem STATUS ee a 3 10SERVO Subsystem ste oe HOS 3 10 1SERVo SELect lt CSAC FILTer gt ins wo 2h we ls 58 3 10 2SERVo MODE lt SLOW MEDium FAST AUTO je c o o Pe e o 60 o o DOO 3 10 3SERVo STATe f Po k a e amp 44 a 459 3 10 4SERVo LOOP lt ON OFFS e EE BH Re eS eR E q a ED
5. 14 2 7 4 6 RS 422 Interface 14 2 7 4 7 1PPS CMOS TTL Input eee DB 2 7 5 Connecting the GPS Glonass Antenna 15 2 7 6 Selecting GNSS Systems 15 2 7 7 Connecting an LCD Display 16 2 7 7 1 LCD Key ER eee ee ee a le 2 7 7 2 LCD Display Pages or a e Ge da O 2 8 Loop parameter adjustment 22 2 9 Performance graphs 24 3 GNSDO SCPI Control Quick Start Instructions 33 3 1 Introduction f oe wt A e OO 3 2 General SCPI Commands 321 ADN erpa do do me d o we O ey ee ee R BD ee ot ae oe 694 32 2 HELP uu elo awl Pe a we a sd 484 3 3 GPS Subsystem goa RM amp OR a amp aoe we 04 3 3 1 GPS SATellite TRAcking COUNt paa ea ee oh D a Bod de 05 3 3 2 GPS SATellite VISible COUNt BB 3 3 3 NMEA Support Woe a oe Be de dod a ee we oe of a BD 3 3 4 GPS PORT lt RS232 USB gt ee o GPS ey ai a E e OO 3 3 5 GPS PORT RE ED de A o ta e E 286 3 3 6 GPS GPGGA ca 86 3 3 7 GPS GGASTat s sos dra dya oa 36 3 3 8 GPS GPRMC 0 2 2 36 2015 Jackson Labs Technologies Inc 1 Low Noise Rubidium GPSDO User Manual J a ck S on Labs 3 3 9 GPS GPZDA 4 4 BT 3 3 10GP
6. Buffered_Output Filter OFF A Spec Buffered Output Filter ON 1 E 14 i i i 1 E 01 1 E 00 1 E 01 1 E 02 1 E 03 1 E 04 1 E 05 Averaging Time t sec REF 5MHz 13dBm 24 2015 Jackson Labs Technologies Inc J a ck S O n Low Noise Rubidium GNSDO tm User Manual Labs Figure 2 18 shows a comparative typical ADEV plot of the Standard Performance option unit with Phase Noise Filter enabled blue trace Phase Noise filter disabled and unit locked to GPS magenta trace and the unit in holdover with the phase noise filter disabled green trace While enabling the TCXO filter on the standard performance option actually increases ADEV noise below several 100 second averaging intervals it significantly improves the units Phase Noise and Spur performance Figure 2 18 Allan Deviation of three different operating modes Allan Deviation sy 1E 9 Tau Sigma Tau 1s 1 67E 11 2s 1318 11 4s 1 05E 1 8s 9516 12 10s 9 27E 12 20s 8 39E 12 40s 7 06E 12 80s 5 81E 12 100s 5 48E 12 bi 4718 12 400s 3576 12 275E 12 1000s 2A3E 12 200 146E 12 4000s 1438 12 8000s 1 20E 12 100008 1 32E 12 200005 1918 12 400008 2096 12 1 11 1E 12 1E 13 1E 14 0 1s 1s 10s 100s 1000s 100005 1000005 Trace Notes Inputfreg Input Amplitude Ref Freq Ref Amplitude Sample Interval_ _ ADEVat0 95 Duration Acquired Instrument LN Rb 0 31 filter dacg 50 efcs 2 phase
7. 3 4 5 GYRO CAL lt float float float float float float gt E oy at an ta a ee AB 3 4 6 GYRO CAL COMPUTE oe Ges Aa ok oe ee AD 3 4 7 GYRO SENS and GPS CAL RESET oo aoe Ged ste He i Ue Ge a ae E A A0 3 4 8 GYRO GLOAD 46 8 5 PTIME Subsystem s s sa esa sa xa 46 3 5 1 PTIMe DATE 46 3 5 2 PTIMe TIME 47 3 5 3 PTIMe TIME STRing 47 3 5 4 PTIMe TINTerval Dopa A ala de AT 3 5 5 PTIME OUTput lt ON OFF gt Rd 3 5 6 PTIMe LEAPsecond Oo ao pog e ae aua Ge ee Gee e aT 3 5 7 PTIMe LEAPsecond PENDing ca a A ob ht der go a it mos q 47 3 5 8 PTIMe LEAPsecond ACCumulated 47 3 5 9 PTIMe LEAPsecond DATE 48 3 5 10PTIMe LEAPsecond DURation 48 3 5 11PTIME Bd AE AN ak oe ns M O 3 6 SYNChronization Subsystem a ss bo aw E 8 aoe Ge ae 48 3 6 1 SYNChronization HOLDover DURation a a a a a te AO 3 6 2 SYNChronization HOLDover INITiate 5 mu amp dae a oh a O 3 6 3 SYNChronization HOLDover RECovery INITiate po BA SC ah ee Se AS 3 6 4 SYNChronization SOURce MODE 2 2 2 2 2 2 2 49 3 6 5 SYNChronization SOURce STATE 50 3 6 6 SYNChronization TINTerval 50 3 6 7 SYNChronization TINTerval CSAC
8. m Hz E 72 te CHANNEL E GNSS RX ean Li SMHZ CMOS OUT ye ad Rubidium resolution Cesium Time Interval Oscillator PPS TE RS 422 SEE APPS Filter OCXO Low Noise Rubidium GPSDO C 2015 Jackson Labs Technologies Inc Las Vegas NV 89144 www jackson labs com rev 1 0 confidential 6 2015 Jackson Labs Technologies Inc J a C K S O n Low Noise Rubidium GNSDO tm User Manual Labs 2 4 Mechanical Drawing The following figure is a mechanical drawing of the LN Rb GNSDO enclosure Figure 2 2 Mechanical Drawing of LN Rb Enclosure CONNECTOR 4X SMA 4 40 CONNECTOR CONNECTOR 16 PIN 2015 Jackson Labs Technologies Inc 7 Low Noise Rubidium GNSDO tm User Manual J a ck S O n Labs 2 5 Operating the unit 1 Connect a 5V compatible GPS or Glonass antenna to the GNSS antenna connector Either GPS or Glonass or combined GPS Glonass L1 antennae are supported It is recommended to use an active antennae with at least 10dB internal gain and a maximum allowable gain of 50dB 2 Plug in a short USB to RS 232 cable adaptor or a standard NULL modem male connector to the RS 232 female plug on the power supply cable harness supplied with the unit Plug in a clean DC power source of between 8V to 32V 36V max to the power pins 15 and 16 of the 16 pin connector
9. C Half duplex Communications Use My Line Feed Settings Send Line Feeds Expect Line Feeds Gen block checksums Execute Activate Flash Bank Technical on line articles about 8051 and lt 4 programming wy esacademy com fag docs i B Press the Select Device button and the window shown in Figure 4 4 will appear 70 2015 Jackson Labs Technologies Inc J a C Kk S O n Low Noise Rubidium GNSDO User Manual Labs Figure 4 4 Device selection window Flash Magic NON PRODUCTION USE ONLY File ISP Options Tools Help EFE ODECE ARM Cortex LPC900 2 clock 80051 80051 XA Technical on line articles about 8051 and X programming www esacademy com fag docs C Expand the ARM CORTEX folder and select the appropriate processor in this case the LPC1768 2015 Jackson Labs Technologies Inc 71 Low Noise Rubidium GNSDO User Manual J a ck S on Labs Figure 4 5 Expanded device selection window LPC2101 LPC2102 LPC2103 LPC2104 LPC2105 LPC2106 LPC2109 4 LPC2114 LPC2119 LPC2124 LPC2129 SH LPC2131 LPC2132 LPC2134 aM Lines an On Line training classes for microcontrollers and embedded networking and Internetworking www esacademy com fag classes D Select the Baud Rate of the Flash Magic utility to be 230 4KB Slower baud rates will also work but will take longer to finish the program cycle E Set the Oscillator MH
10. This command sets the Frequency Adjustment in units of parts per trillion 1E 12 Like the query command described above the Frequency Adjustment is relative to the latched frequency correction stored in the CSAC or MAC The control range with this command is 1 ppm This command has the following format CSAC STeer lt int gt 1000000 1000000 2015 Jackson Labs Technologies Inc 63 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 3 11 4 CSAC STATUS This query returns the status value in 0 1 as shown below If the unit does not indicate STATUS 0x0 after 10 minutes after power on the MAC may not have locked properly and may need to be power cycled This can happen if power supplies with insufficient current capability to handle the MAC warmup currents are used 0x1 MAC not locked 0x0 MAC locked and healthy 3 11 5 CSAC MODE This query returns the Rubidium oscillator mode as shown below 0x0000 Analog tuning disabled 0x0001 Analog tuning enabled 3 11 6 CSAC TECcontrol This query returns the Rubidium oscillator TEC Control value in mDegC 3 11 7 CSAC TCXO This query returns the TCXO Tuning Voltage 0 2 5 VDC tuning range 10 ppm 3 11 8 CSAC SIGnal This query returns the indication of the Rubidium Vapor Cell DC interrogation signal level in mV 3 11 9 CSAC HEATpackage This query returns the Physics package heater power in mW 3 11 10 CSAC TEMP This query returns the Temperature
11. 5 3 GPSCon Installation 5 4 Using GPSCon 5 4 1 Setting the options 5 4 1 1 Communication Parameters 5 4 1 2 Auxiliary parameters 5 4 1 3 Other options 5 4 2 Sending manual commands to the receiver 5 4 3 Use of the mouse in graph mode 5 4 4 Exporting the graphics Certification and Warranty 6 1 Certification 6 1 1 Warranty 6 1 2 Limitation of Warranty 6 1 3 Exclusive Remedies 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO tm User Manual Labs Introduction 1 1 Overview The Low Noise Rubidium Global Navigation System Disciplined Oscillator GNSDO offers the traditional benefits of Rubidium Reference oscillators such as high stability and very low drift but differentiates itself from legacy products by operating with extremely low phase noise very low power consumption and small size and weight SWAP The LN Rb GNSDO also integrates a sophisticated software control and monitoring system a GPS Glonass BeiDou QZSS SBAS receiver a wide range avionics power supply USB LCD RS232 RS422 CMOS interfaces and an ovenized Phase Noise and ADEV filter oscillator with world class performance The LN Rb GNSDO unit may also be ordered in an ultra low power variant which features a Cesium Vapor Cell CSAC reference oscillator instead of the Rubidium MAC and reduces the overall power consumption to less than 1 4W while providing excellent Phase Noise performance and less than 2 minute
12. CSAC Specifications and loop parameters change between these four ordering options but all units support the same basic SCPI and GNSS feature set Differentiation is done by selecting the type and quality of atomic clock oscillator as well as the type and quality of the Crystal Phase Noise Filter oscillator The CSAC variant of the product also removes the two direct OCXO 10MHz SMA output connectors from the enclosure Please refer to the Specifications sheets for additional details on the specifications and parameters of these ordering options 2 2 Powering Up the Unit The LN Rb GNSDO may be powered from an external 8V to 36V DC source with 12V nominal The unit consumes typically around 18W for several minutes during warmup and will then settle into a steady state power consumption of less than 5 6W A power supply of 12V with at least 1 5A capability is suggested The CSAC ordering option of the product consumes less than 1 4W steady state less than 0 12A at 12V Serial communications can be established through the RS 232 or USB ports at 115 200 baud 8N1 no flow control set on the terminal JLT recommends using the TeraTerm Pro application or Z38xx both of which can be downloaded for free Once serial communications have been established the user can try sending and experimenting with the following useful SCPI commands syst stat gps 2015 Jackson Labs Technologies Inc 5 Low Noise Rubidium GNSDO tm User Manual J a ck
13. Status Time Map J Graph Export Help About Low Noise Rubidium GNSDO User Manual E ackson Labs FireFly ll Firmware Rev 2 19 o Lite fed 02 38 51 16 1410 EFC 2 414208 ad 0m sd 0 05m I TI max ns 20 H 2 4r A 159494 Temp E Filter coeff 0 025 Stat Span mins 15000 Stop Hide Not Tracking l PRN El z 15 1 40 na h AN Ay i VTC 1 35 45 16 Now 2010 LaT N 27 15 29 756 LON W 121 57 40 195 7 20 m MSL q Sat count 69 0 ns start 17 27 41 15 11 10 UTC Send serv tar y 18 02 47 15 11 10 UTC Receiver timeout z servitar T Log Status M Log sat count T7 Translate time codes 2584 95 6348 7 66236 0 0054106 4 072305 0 00530379 Log EFC 2414209 Options sepi gt IV Tlto GPS F11E 09 0 158524 I Log PU fl in el Update now D Continuously read error queue Flash LED Last error r 5 4 4 Exporting the graphics The settings which control the mode of the Export function are contained in the Options dialog Export allows you to create an image file of either the graph or the satellite map You select which you want using the radio buttons If you select Graph you have the option to export only that which is currently visible or to export the graph which is a plot of the entire logfile contents Use the checkbox All to make this choice You may nominate a size in X and Y The file format may be BMP JPG GIF or PNG Your settings will be stored and will be the default next time you op
14. 00 t 240 0 1237 360 0 1244 180 0 1253 7200 130 2 90 9 100 9 1109 120 9 7 130 0 1408 150 0 160 0 1Hz 10Hz 400 Hz kHz 10 kHz 100 kHz Trace Notes inputFreg Input Amplitude Re Amplitude Sampleimerval _ _dBcHzat10kHz Duration Required Instrument 10 000 MHz 10 5 dBm 10000 MHz 6 2dBm TimePod 5330A 30 2015 Jackson Labs Technologies Inc Low Noise Rubidium GNSDO tm User Manual Jackson m Figure 2 23 shows the typical GPS disciplined ADEV performance of the unit when ordered with the low power low noise Cesium Atomic Clock CSAC oscillator option and after stabilizing for 48 hours Figure 2 23 LN CSAC Typical ADEV Allan Deviation sy 1E 10 Tau Sigma Tau 1s 137 11 2s 1 82E 11 4s 221E 11 2376 11 10s 236E 11 20s 2 136 11 40s 1 78E 11 80s AMIE 100s 1 30E 11 200s 973E 12 400s 6 95E 12 800s 453E 12 1000s 3916 12 2000s 2 22E 12 16 11 4000s 1 27E 12 8000s TEA 100005 5 88E 13 200008 2788 13 18 12 18 13 0 1s 1s 10s 100s 1000s 100005 1000005 10 000 MHz 6 2dBm 1648555pts TimePod 5330A 2015 Jackson Labs Technologies Inc 31 Low Noise Rubidium GNSDO tm User Manual J a ck S on Labs 32 2015 Jackson Labs Technologies Inc J a C ks O n Low Noise Rubidium GNSDO User Manual Labs GNSDO SCPI Control Quick Start Instructions 3 1 Introduction The Low No
15. 1 Introduction The following is a short tutorial on how to upgrade the Low Noise Rubidium GNSDO firmware Please follow the instructions in order to prevent corrupting the Low Noise Rubidium GNSDO Flash which may require reflashing at the factory With some practice the entire Flash upgrade can be done in less than two minutes even though the following seems like a fairly long list of instructions 4 2 ISP Flash Loader Utility Installation Jackson Labs Technologies Inc recommends using the Flash Magic utility to upgrade the contents of Flash memory on the Low Noise Rubidium GNSDO It is available for download on the Flash Magic website http www flashmagictool com Follow the directions given on the website for installing the utility on your computer Note The Philips LPC2000 utility that is used on other Jackson Labs Technologies Inc products will not support the newer LPC1768 processor used on the LN Rb GNSDO 4 3 Putting the PCB into In Circuit Programming ISP mode Momentarily short out pins 1 and 3 on the 16 pin main power connector J1 or alternatively pins 1 and 2 of ISP RESET header J2 on the PCB inside the enclosure using a jumper wire or other conductive material during power on See Figure 4 1 Both LED s on the PCB should remain off indicating the unit is properly placed into ISP mode If the LED s light up after power on the unit is not in ISP mode 2015 Jackson Labs Technologies Inc 67 Low Noi
16. Baud Rate SADO Y Erase block 4 0x004000 0x004FFF Interface None ISP Erase block 5 0x005000 0x005FFF R Erase all Flash Code Rd Prot Oscillator MHz 7 Erase blocks used by Hex File Step 3 Hex File Hex File FireFly llA_2 19 hex Modified Unknown more info Fill unused Flash Gen block checksums Execute Your Training or Consulting Partner Embedded Systems Academy www esacademy com IL O 2015 Jackson Labs Technologies Inc 69 Low Noise Rubidium GNSDO User Manual J a ck S on Labs Please Note that the latest versions of Flash Magic contain a new communications option that is likely set incorrectly by default If this setting is incorrectly selected Flash Magic may not be able to communicate properly to the processor Open the Options and Advanced Options tabs on the application Please ensure that the Use My Line Feed Settings Send Line Feeds and Expect Line Feeds options are all highlighted and selected as show in Figure 4 3 below Press OK to get back to the main menu Figure 4 3 Required Flash Magic Communications Options Flash Magic NON PRODUCTION USE ONLY File ISP Options Tools Help SH ADE VE gt Y Step 1 Communications Advanced Options Communications Hardware Config Security Just In Time Code Timeouts Misc C High Speed Communications Magir 1 Baud Rat 30401
17. Hardware version of the board 3 9 7 SYSTem LCD CONTrast 0 1 0 This command sets the contrast of the LCD Typical settings are 0 2 3 9 8 SYSTem LCD CONTrast This query returns the current contrast of the LCD 56 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs 3 9 9 SYSTem LCD PAGE 0 9 This command displays the requested page on the LCD Ten different pages are supported as described in Section 2 7 7 2 The following table lists the LCD page numbers and corresponding names Value LCD Page 0 Time Date 1 GNSS Position 2 GNSS Height 3 GNSS Systems 4 Rubidium Oscillator Steering 5 Rubidium Oscillator Status 6 Loop TINT and FEE 7 Navigation 8 GPS UTC Time 9 Survey Status 3 9 10 SYSTem LCD PAGE This query returns the current page of the LCD 3 9 11 SYSTem COMMunicate USB BAUD lt 9600 19200 38400 57600 115200 gt This command sets the speed of the serial USB port 3 9 12 SYSTem COMMunicate USB BAUD This query returns the speed of the serial USB port 3 9 13 SYSTem STATus This query returns a full page of GNSS status in ASCII format The output is compatible with GPSCon This command returns one of the most comprehensive GNSS and oscillator status pages O 2015 Jackson Labs Technologies Inc 57 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 3 10 SERVO Subsystem This subsystem regroups all t
18. If the short term drift ADEV 100s gt 100ns HEALTH STATUS l 0x100 For the first 3 minutes after a phase reset HEALTH STATUS l 0x200 If the Rubidium oscillator indicates an alarm HEALTH STATUS l 0x400 If the GNSS receiver indicates a strong jamming HEALTH STATUS l 0x800 signal of gt 50 range is O to 255 and has no GNSS fix If the filter oscillator loop is not locked with HEALTH STATUS l 0x1000 Rubidium oscillator loop selected only As an example if the unit is in GNSS holdover and the UTC phase offset is gt 250ns then the following errors would be indicated 1 UTC phase gt 250ns Ox4 2 GPS in holdover 0x10 Oring these values together results in 0x10 0x4 0x14 The unit would thus indicate HEALTH STATUS 0x14 and the Green LED as well as the LOCK_OK output on connector J1 would go off indicating an event is pending A health status of 0x0 indicates a properly locked and warmed up unit that is completely healthy 3 6 19 SYNChronization TINTerval THReshold 50 2000 52 This command selects the Rubidium or filter oscillator 1PPS phase offset threshold as compared to the reference 1PPS at which point the unit will initiate a counter reset jam sync aligning the Rubidium or filter oscillator generated 1PPS with the reference 1PPS phase The Rubidium or filter oscillator 1PPS phase is allowed to drift up to this threshold before a jam sync is initiated The 2015 Jackson Labs Technologies I
19. J1 Plug in the Ground connection to pins 12 and 14 of connector J1 RS 232 Serial TX and RX signals are available on pins 9 and 8 respectively of connector J1 Make sure not to accidentally short out adjacent pins 13 and 15 of connector J1 as this would damage the board WARNING WHEN OPERATING THE UNIT OUTSIDE OF ITS ENCLOSURE OR WITH AN OPEN LID PLEASE MAKE SURE NOT TO CONFUSE POWER CONNECTOR J1 AND LCD CONNECTOR J3 AS THESE TWO CONNECTORS ARE MECHANICALLY IDENTICAL AND ARE THUS EASY TO MIX UP APPLYING POWER TO LCD CONNECTOR J3 WILL SEVERELY DAMAGE THE PC BOARD The unit will now discipline its oscillators to the GNSS system A Lock indication 3 3V on pin 7 of connector J1 on the internal Green LED and on the SCPI status sentences will typically happen in less than 20 minutes after power on with a GNSS antenna connected Without a GNSS feed the unit will work as a traditional Atomic Clock in Rubidium holdover mode and in this mode the unit will slowly blink the internal Green LED and the LOCK OK output on pin 7 at 0 25Hz to indicate when the unit has internally locked the OCXO to the Rubidium reference the unit is healthy and no events are pending No indication on the internal Green LED and on pin 7 OV signifies that an event happened or the unit is not warmed up and locked yet and this event status can be queried in detail with the SYNC HEALTH and other SCPI commands Please note that the GNSS receiver establishes the internal ant
20. Labs Technologies Inc or a service facility designated by Jackson Labs Technologies Inc Customer shall prepay shipping charges and shall pay all duties and taxes for products returned to Jackson Labs Technologies Inc for warranty service Except for products returned to Customer from another country Jackson Labs Technologies Inc shall pay for return of products to Customer If Jackson Labs Technologies Inc is unable within a reasonable time to repair or replace any product to condition as warranted the Customer shall be entitled to a refund of the purchase price upon return of the product to Jackson Labs Technologies Inc 6 1 2 Limitation of Warranty The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by the Customer Customer supplied software or interfacing unauthorized modification or misuse opening of the instruments enclosure or removal of the instruments panels operation outside of the environmental or electrical specifications for the product or improper site preparation and maintenance JACKSON LABS TECHNOLOGIES INC SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 2015 Jackson Labs Technologies Inc 81 Low Noise Rubidium GNSDO User Manual J a ck S on Labs PURPOSE No license express or implied by estoppel or otherwise to any intellectual property rights is granted by this document Jackson Labs Technologies Inc pro
21. Stationary Used in stationary applications Pedestrian Used in man pack pedestrian settings Automotive Vehicular velocity applications Sea Used on Ships where altitude is expected to be constant Airborne lt 1g Airborne applications with less than 1g acceleration Airborne lt 2g Airborne applications with less than 2g acceleration Airborne lt 4g Airborne applications with less than 4g acceleration Automatic Mode Select one of the above states 0 7 based on the actual velocity of the vehicle The Low Noise Rubidium GNSDO uses a GNSS receiver that is capable of running in a stationary mode with Position Auto Survey called Position Hold Mode This mode increases timing stability by storing the position into memory and solving the GNSS signal only for time as the position is not expected to change This allows operation with only one Sat vehicle or over determination of the 2015 Jackson Labs Technologies Inc 39 Low Noise Rubidium GNSDO User Manual J a ck S on Labs timing pulse Two modes can be selected for Auto Survey operation see section 3 3 19 for a description of the GPS TMODE command 1 Manually setting Timing Mode to ON with a hard coded position in NVRAM 2 Enabling Auto Survey to start automatically after power on by setting Timing Mode to RSTSURV If either one of the above two GPS TMODE Auto Survey Position Hold modes is selected the GPS DYNAMIC MODE command is disabled internally and its setti
22. This command has the following format SERVo FALEngth lt int gt 100 20000 3 10 18 SERVo This command returns the result of the following queries SERVo SELect SERVo LOOP 62 O 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs SERVo COARSEDAC only with filter servo loop selected SERVo DACGain SERVo EFCScale SERVo EFCDamping SERVo FILTerlength SERVo PHASECOrrection SERVo TEMPCOmpensation SERVo AGINGcompensation SERVo 1PPSoffset SERVo TRACe PORT SERVo TRACe SERVo FASTlock SERVo FALEngth 3 11 CSAC Subsystem The following commands are used to query the microcontroller built into the Rubidium oscillator itself Please note that the CSAC nomenclature is used instead of MAC for backwards compatibility to all legacy JLT CSAC GNSDO products However all the commands in the CSAC Subsystem can also be accessed using the MAC name i e MAC STeer or MAC STATus 3 11 1 CSAC RS232 This query returns the state OK or FAIL of the serial communication between the main CPU and the Rubidium oscillator internal microcontroller When the state is FAIL there is a communication breakdown and the unit should be power cycled to clear the communication error 3 11 2 CSAC STeer This query returns the current Frequency Adjustment in units of parts per trillion 1E 12 The Frequency Adjustment is relative to the latched frequency stored in the CSAC or MAC 3 11 3 CSAC STeer
23. behavior after power on 22 49 20 07 15 EFC 2 394489 ad 0 02m sd 1 91m 40234 61 68 Current TI av 44 86n sd 43 4n a mi MO q Sat count 104 9 start 20 57 55 20 07 15 UTC 1 41 hrs 4 o O 2015 Jackson Labs Technologies Inc 27 Low Noise Rubidium GNSDO tm User Manual J a ck S on Labs Typical Phase Noise performance of different ordering options Phase Noise f in dBc Hz 80 0 PM Spur Offset Hz 02 120 0 240 0 m 270 0 360 0 480 0 91060 0 100 0 110 0 120 0 130 0 140 0 150 0 160 0 170 0 180 0 1Hz Notes inputFrea input Amplitude T Reffrea Ref Amplitude Sample interval dBcHzat50khz Duration Acquired instrument Unsaved 10 000 MHz 2 9 dBm 10 000 MHz 125d8m 0 1005 166 9 1h 1m54s 37138pts TimePod 5330A 10 000MHz 3 1 dBm 10 000MHz 12 5 dBm 0 100s 168 6 21h14m49s 764892pts TimePod 5330A 10 000 MHz_ 9 9 dBm 10 000 MHz 12 5 dBm 0 1005 171 9 96h 656982 pts TimePod 53304 28 2015 Jackson Labs Technologies Inc J a ck S O n Low Noise Rubidium GNSDO tm User Manual Labs Figure 2 21 compares the performance of the TCXO filtered Phase Noise output to the raw MAC oscillator output Phase Noise spectrum The TCXO clearly removes all spurs present in the MAC output and significantly improves the overall Phase Noise performance of the unit Selecting the TCXO output versus the raw MAC ou
24. is divided by 2 and then drives this connector through a buffer that can source up to 15mA 2 7 4 2 LOCK_OK Output The LOCK_OK EVENT output on the 16 pin main connector J1 pin 7 can drive an external LED with up to SmA through a 330 Ohms or higher series resistor A high 3 3V on this signal signifies that the unit is fully locked warmed up healthy and no events are pending A low OV on this signal shows that the unit is either unlocked not fully warmed up a hardware error happened or an event is pending A low thus does NOT necessarily signify that the units output frequency is unlocked rather the user should query the health status sentence for the event s that caused this signal to go low with the command SYNC HEALTH See also section 3 6 18 2 7 4 3 10MHz Sine Wave Outputs The enclosure has three 10MHz output connectors Two are labeled LOW NOISE and one is labeled UNFILTERED The two low noise outputs are driven directly by the OCXO through a passive splitter and are completely un buffered buffers add about 1dB to 2 dB to the noise floor and 2015 Jackson Labs Technologies Inc 13 Low Noise Rubidium GNSDO tm User Manual J a ck S O n Labs would thus have degraded the units noise performance These two un buffered outputs should both be terminated into 50 Ohms resistive terminations at all times and two SMA terminators are typically shipped with the unit for this purpose Please note that the low noise O
25. measured by the Rubidium oscillator unit in C 3 11 11 CSAC FWrev This query returns the Firmware version of the Rubidium oscillator unit 64 2015 Jackson Labs Technologies Inc J a C Kk S O n Low Noise Rubidium GNSDO User Manual Labs 3 11 12 CSAC SN This query returns the Serial Number of the Rubidium oscillator in the form YYMMCSNNNNN where Y YMM is the year and month of production and NNNNN is the serialized unit of that month 3 11 13 CSAC LIFEtime This query returns the accumulated number of hours that the Rubidium oscillator has been powered on since the last factory reset of the Low Noise Rubidium GNSDO board The value is stored in the external NVRAM and updated every hour when the unit is powered on 3 11 14 CSAC STeer LATch ONCE This command stores the momentary steering offset into the Rubidium oscillator s internal NVRAM This is done automatically by the firmware once every 24 hours so as not to damage the Rubidium oscillator s NVRAM which has a limited number of write cycles The user may force this value to be stored into the Rubidium oscillator by issuing the CSAC STeer LATch ONCE command 3 11 15 CSAC This query displays all the CSAC queries defined above 2015 Jackson Labs Technologies Inc 65 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 66 2015 Jackson Labs Technologies Inc J a C ks O n Low Noise Rubidium GNSDO User Manual Labs Firmware Upgrade Instructions 4
26. sentences Generic NMEA and SCPI GPIB commands on three serial interfaces allow very fast integration into legacy applications and by using the NMEA serial strings the unit can behave like a standard GNSS receiver albeit with better than 1 meter horizontal accuracy typically and full WAAS EGNOS MSAS SBAS as well as Glonass GPS BeiDou QZSS support out of the box The SCPI command interface is fully backwards compatible to the popular JLT CSAC GPSDO and FireFly command systems and the unit can thus be used as a drop in upgrade for applications designed for these legacy Jackson Labs Technologies Inc products 1 2 Operating Principles A Rubidium Vapor Cell is excited from a VCEL Laser source The VCEL is modulated at 3 4 GHz to produce a complementary pair of sidebands separated by the Rubidium ground state hyperfine frequency of 6 834 GHz The hyperfine transition frequency of the Rubidium Vapor cell is affected by adverse environmental influences and long term frequency and phase errors are thus present in the MAC as in every Atomic Clock To calibrate these errors out and to achieve phase lock to UTC GNSS the LN Rb GNSDO uses a GNSS receiver to generate a highly accurate though unstable 1PPS signal and this noisy 1PPS signal is compared with a 1PPS signal generated by the MAC sourced 10MHz using a 20ps time interval counter The VCEL is digitally tuned to shift the frequency up or down slightly in 0 001 parts per trillion or 1E 015 resoluti
27. shows the GNSS coordinates of the antenna position Figure 2 7 GNSS position display page GNSS Height Figure 2 8 This page shows the height in MSL of the GNSS antenna as well as the operating mode HOLD Position Hold mode 18 2015 Jackson Labs Technologies Inc Jac k S on Low Noise Rubidium GNSDO tm User Manual Labs e GNSS Status Page Figure 2 9 shows the reception status of the different GNSS systems The number of tracked satellites is shown or OFF is displayed if the GNSS system is disabled by user command see also section 3 3 27 The following GNSS systems are currently supported in the LCD display GPS Glonass BeiDou and QZSS Figure 2 9 GNSS status page e MAC Steering Figure 2 10 This page shows the internal STATUS indication of the MAC oscillator itself 0x0 indicates normal operation It also shows the MAC Oscillator steering offset required to maintain UTC lock which is normalized to 1E 012 offsets The MAC steering offset is programmed into the MAC oscillator NVRAM once every 24 hours at which point the offset is set to 0 again This allows the MAC oscillator to power on with the last internal offset stored in NVRAM effectively storing the calibration parameter inside the MAC oscillator once per day 2015 Jackson Labs Technologies Inc 19 Low Noise Rubidium GNSDO tm User Manual J a ck S on Labs Figure 2 10 MAC steering display page e MAC Status Figure 2 11 This
28. subsequent Auto Survey will overwrite the Hold position The Hold position is stored in ECEF coordinates 3 3 24 GPS SURVey STATus This query displays the current status of the Auto Survey The status of the survey is in one of the 3 states ACTIVE a survey is in progress VALID a survey has been achieved successfully and the GNSS receiver is now using this Hold position as reference INVALID no survey is in progress or has been achieved since the last power cycle When in ACTIVE or VALID state this query will also display the duration the Hold position in ECEF coordinates and the position variance 3 3 25 GPS INITial DATE lt yyyy mm dd gt This command allows the manual setting of the internal RTC DATE when operating the unit in GNSS denied environments This command is compatible to the PTIME OUT ON command described in section 3 5 to allow automatic time and date synchronization of two units to each other The internal RTC is driven by the highly stable Rubidium oscillator s 10MHZ signal and thus has very high accuracy 2015 Jackson Labs Technologies Inc 43 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 3 3 26 GPS INITial TIME lt hour min sec gt This command allows manual setting of the internal RTC TIME when operating the unit in GNSS denied environments This command is compatible to the PTIME OUT ON command described in section 3 5 to allow automatic time and date synchronization of two units to eac
29. you must either set the span control to zero or right double click in the graph When you have locked the start and stop time using the mouse you can scroll left or right through the data without changing the span To scroll to a later time use Shift Left click To scroll to an earlier time use Shift Right click Double left click to release everything The time span indication at the lower right of the graph will turn red to signify that mouse override is in effect Figure 5 5 Graph display gt GPSCon Utility Pro GPSCon COM8 x Ss E ackson Labs FireFly Il Firmware Rev 2 19 Life 440 EFC 2 414181 ad 0m sd 0 04m J TI max ns 20 emp Fiter coeff 0 025 Let Jr Stop Span mins 15000 o Hide Not Tracking 0 PRN El z TI av 0 03n sd 11n 2 41396 0 13560 93 0 ns ed Als ld A A LON W 11 57 40 127 VTC 2 36 25 16 Now 010 Lat N 27 15 39 756 6 50 m MSL 77 0 ns 0 start 14 45 02 07 11 10 UTC 203 86 hrs Send serztar 18 02 47 15 1110 UTC Receiver timeout 7 servitar T Log Status M Log sat count Translate time codes 2584 95 6348 7 66236 0 0054106 4 072305 0 00530379 M LogEFC 2414181 Options oi F TltoGPS fT1E 08 0157483 FT Log PU fi Pic E EE D Continuously read error queue Flash LED Last error t sys time 78 2015 Jackson Labs Technologies Inc Jackson m Figure 5 6 Expanded Graph Display GPSCon Utility Pro GPSCon COM8
30. 2 0 To enable move J4 1 GND J4 2 DM J4 3 DP connection to GNSS R42 to position R43 stuff receiver connector J4 Connect to uBlox uCenter application J5 GNSS Antenna GNSS Antenna 5V Amplified L1 GPS and or Center RF Input Shield GND Glonass Antenna 10dB to 50dB antenna gain recommended OUT J1 5MHz OUT 5MHz output 5V CMOS series terminated Center RF output Shield GND with 50 Ohms OUT_J2 1PPS OUT 1pps output 5V CMOS either from MAC Center RF output Shield GND oscillator or OCXO oscillator software selectable series terminated with 50 Ohms OUT_J3 J4 10MHz Buffered 10MHz output from Sine wave 13dBm Center RF output Shield GND isolated distribution amplifier 1dBm either from MAC oscillator or OCXO oscillator software selectable Leave un terminated when unused 2015 Jackson Labs Technologies Inc 11 Low Noise Rubidium GNSDO tm User Manual Jackson 10MHz Unbuffered OUT_J5 J6 10MHz unbuffered output directly from OCXO Sine wave 5dBm 5dBm 2dBm Terminate with 50 Ohms when unused Center RF output Shield GND 2 7 2 RS 422 Connector JP2 The unit supports RS 422 level differential input and outputs on internal connector JP2 RS 422 levels are essentially high speed 3 3V CMOS outputs with the capability to drive 120 Ohms differential terminations as defined in the RS 422 standard 10MHz 1PPS and SCPI serial stream outputs in RS 422 levels ar
31. 5 71E 12 1E 11 100s 6 11E 12 200s 7 21E 12 400s 7 36E 12 800s 5 60E 12 1000s 4 74E 12 2000s 2 58E 12 TE 4000s 1 47E 12 18 13 10s 100s 1000s 10000s 100000s Po Trace Notes Input Freq Sample Interval ADEV at 7s 26604 pts N Rb short holdover tests Unsaved 1 44m 20s Symmetricom 5115A 512XA LN Rb Filter GPS nav mode 22h 48m Os 820798 pts Symmetricom 5115A 512XA LN Rb Filter GPS tmode on 1d 2h 44m 19s 962591 pts Symmetricom 5115A 512XA 14 567MHz al E 24 567 MH 100 1h 59m 375 71773 pts Symmetricom 5115A512XA Vira das EA vts Summon TRENS A I LN Rb Filter GLONASS tmode on Unsaved 2d 19h 11m 39s 2418985 pts Symmetricom 5115A 512XA LN Rb Filter GLONASS nav mode Unsaved 144 h 1105839 pts Symmetricom 5115A 512XA 26 2015 Jackson Labs Technologies Inc J a ck S O n Low Noise Rubidium GNSDO tm User Manual Labs Figure 2 20 shows the a typical warmup phase offset behavior of the Premium OCXO option unit after power on The frequency will quickly stabilize and the phase will slowly adjust over the next number of hours During this time the phase offset error between the MAC oscillator and the GPS 1PPS and the MAC oscillator and the filter OCXO may be queried with the SYNC TINT serial command Full stabilization of the phases to each other to nanosecond levels may take up to 24 hours or longer depending on how long the unit had been powered off and how stable the environment is Figure 2 20 Typical OCXO filter phase offset
32. AUD lt 9600 19200 38400 57600 115200 gt SYSTem COMMunicate USB BAUD SYSTem STATus 2015 Jackson Labs Technologies Inc 55 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 3 9 1 SYSTem COMMunicate SERial ECHO This command enables disables echo on the serial port Echo should be turned off when using the Z38xx application program This command has the following format SYSTem COMMunicate SERial ECHO lt ON OFF gt 3 9 2 SYSTem COMMunicate SERial PROmpt This command enables disables the prompt scpi gt on the SCPI command lines The prompt must be enabled when used with the software GPSCon This command has the following format SYSTem COMMunicate SERial PROmpt lt ON OFF gt 3 9 3 SYSTem COMMunicate SERial BAUD This command sets the RS 232 port serial speed The serial configuration is always 8 bit 1 stop bit no parity no flow control Upon Factory reset the speed is set at 115 200 baud This command has the following format SYSTem COMMunicate SERial BAUD lt 9600 19200 38400 57600 115200 gt 3 9 4 SYSTem FACToryreset ONCE This command applies the Factory Reset setting to the NVRAM All aging tempco and user parameters are overwritten with factory default values and the unit should be self calibrated by operating with GNSS reception for 72 continuous hours 3 9 5 SYSTem ID SN This query returns the serial number of the board 3 9 6 SYSTem ID HWrev This query return the
33. Acceleration can be measured with up to 3g range on all three axis Please note that since the tilt angle is calculated from the acceleration vectors using gravity as a reference that the tilt angles will actually exceed 90 Degrees when acceleration greater than 1g is applied 3 4 3 GYRO PORT lt RS232 USB gt This commands specifies the communication port where the GYRO traces will be sent 3 4 4 GYRO PORT This query returns the port where the GYRO traces are sent 3 4 5 GYRO CAL lt float float float float float float gt Similar to the GPS GYRO CAL command Used to manually calibrate the gain and offset of the Accelerometer output Please see the GPS GYRO CAL command for details See also the GYRO CAL COMPUTE command for a semi automated calibration method 3 4 6 GYRO CAL COMPUTE This command can be used to automatically compute the offset and gain compensation of the accelerometer output for units that are not factory calibrated The goal is to have the unit indicate a 2015 Jackson Labs Technologies Inc 45 Low Noise Rubidium GNSDO User Manual J a ck S on Labs range of 1 0g on all three axis when slowly rotated through the axis as well as 0 0g for any axis that is perpendicular to the earth s gravity The user must establish the minimum and maximum g loads that are displayed on all three axis by slowly tilting the unit over 180 Degrees on all three axis These values are written down on a piece of paper
34. CXO has significant sensitivity to load changes and simply removing or plugging in a cable on one of these two low noise SMA connectors may cause the unit to go unlocked and it could take up to an hour or more to fully recover the units stability and frequency accuracy These two connectors should thus only be changed with the units power turned off A secondary 10MHz UNFILTERED SMA output is available that is fully buffered and isolated and driven by a multiplexor circuit with software control The user can select the 1OMHz output source to be the MAC Rubidium raw 10MHz output or a buffered version of the low noise filter oscillator output Load changes on this connector will not affect frequency accuracy or stability and the user can switch between the two 1OMHz sources at will without affecting the frequency stability of the unit This connector should thus be used for operations where a cable is connected or removed from the unit during normal operation of the unit This SMA connector may be left open if unused One additional UNFILTERED 10MHz output is available internally to the enclosure on an MMCX connector as shown in Figure 2 3 This output is operated in parallel to the SMA unfiltered output and uses an isolated distribution amplifier 2 7 4 4 CMOS 1PPS Outputs The main 1PPS output is driven on the 1PPS SMA connector The unit also has one independently driven 5V CMOS output on connector J1 pin 13 These outputs are
35. D 3 10 5SERVo COARSedac D9 3 10 6SERVo DACGain a a a BY 3 10 7SERVo EFCScale 60 3 10 8SERVo FILTerlength 60 3 10 9SERVo EFCDamping O cas te dt te et gt oe a ae te 460 3 10 10SERVo TEMPCOmpensation Sd oe at da ee ee Ge a O 3 10 11SERVo AGINGcompensation BO 3 10 12SERVo PHASECOrrection 60 2015 Jackson Labs Technologies Inc iii Low Noise Rubidium GPSDO User Manual 3 10 13SERVo 1PPSoffset 3 10 14SERVo TRACe PORT 3 10 15SERVo TRACe 3 10 16SERVo FASTlock 3 10 17SERVo FALEngth 3 10 18SERVo 3 11CSAC Subsystem 3 11 1CSAC RS232 3 11 2CSAC STeer 3 11 3CSAC STeer 3 11 4CSAC STATus 3 11 5CSAC MODE 3 11 6CSAC TECcontrol 3 11 7CSAC TCXO 3 11 8CSAC SIGnal x ok 3 11 9CSAC HEATpackage 3 11 10CSAC TEMP 3 11 11CSAC FWrev 3 11 12CSAC SN 3 11 13CSAC LIFEtime i 3 11 14CSAC STeer LATch ONCE 3 11 15CSAC 4 Firmware Upgrade Instructions 4 1 Introduction 4 2 ISP Flash Loader Utility Installation 4 3 Putting the PCB into In Circuit Programming ISP mode 4 4 Downloading the Firmware 4 4 1 Using the Flash Magic Flash Programming uti 4 5 Verifying Firmware Update GPSCon Utility 5 1 Description 5 2 Z38xx Utility
36. GNSS receiver or external 1PPS reference This command only operates only on the Rubidium oscillator servo loop 3 6 8 SYNChronization TINTerval FILTer This query returns the Time Interval between the filter oscillator 1PPS output and the Rubidium oscillator 1PPS output This command operates only on the filter servo loop 3 6 9 SYNChronization IMMEdiate This command initiates a near instantaneous alignment of the Rubidium or filter oscillator 1PPS output with the reference 1PPS To be effective this command has to be issued while not in holdover This command operates on the selected servo loop 3 6 10 SYNChronization FEEstimate This query returns the Frequency Error Estimate similar to the Allan Variance using a 1000s measurement interval and comparing the internal 1PPS to GNSS or filter oscillator 1PPS offset Values less than 1E 012 are below the noise floor and are not significant This query reports the value for the selected servo loop 50 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs 3 6 11 SYNChronization LOCKed This query returns the lock state 0 OFF 1 ON of the PLL controlling the Rubidium or filter oscillator This query reports the value for the selected servo loop 3 6 12 SYNChronization 0UTput 1PPs RESET lt ON OFF gt This command allows the generation of the 1PPS pulse upon power on without an external GNSS antenna being connected to the unit By defaul
37. LDover RECovery INITiate SYNChronization SOURce MODE lt GPS EXTernal AUTO gt SYNChronization SOURce STATE SYNChronization TINTerval SYNChronization TINTerval CSAC SYNChronization TINTerval FILTer SYNChronization TINTerval THReshold 50 2000 SYNChronization IMMEdiate SYNChronization FEEstimate SYNChronization LOCKed SYNChronization OUTput 1PPS RESET lt ON OFF gt 48 O 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs SYNChronization OUTput 1PPS RESET SYNChronization OUTput 1PPS DOMAIN lt CSAC FILTer gt SYNChronization OUTput 1PPS DOMAIN SYNChronization OUTput FILTer lt ON OFF gt SYNChronization OUTput FILTer SY NChronization HOLDover STATe SYNChronization 3 6 1 SYNChronization HOLDover DURation This query returns the duration of the present or most recent period of operation in the holdover and holdover processes This is the length of time the Rubidium oscillator was not locked to the GNSS receiver or external 1PPS reference and thus coasting The time units are seconds The first number in the response is the holdover duration The duration units are seconds and the resolution is 1 second If the Receiver is in holdover the response quantifies the current holdover duration If the Receiver is not in holdover the response quantifies the previous holdover The second number in the response identifies the holdover state A value of 0 indicat
38. N in the interval 0 255 The command is disabled during the initial warm up phase This command has the following format GPS GPZDA lt int gt 0 255 3 3 10 GPS GPGSV This command instructs the Low Noise Rubidium GNSDO to send the NMEA standard string GPGSV every N seconds with N in the interval 0 255 The command is disabled until the GNSS receiver achieves a first fix GPS GPGSV lt int gt 0 255 Please note that due to the large number of GNSS satellites that can be tracked in this unit more than the customary four GSV messages can be sent once per second With multiple GNSS systems enabled a typical sky view may generate up to six GSV messages per second To simultaneously support all available GNSS systems the following PRN numbering scheme modified from the traditional NMEA standard is being used GNSS Type SV Range GPGSV PRN vehicle numbering GPS G1 G32 1 32 SBAS 120 S158 33 64 152 158 Galileo E1 E36 301 336 BeiDou B1 B37 401 437 IMES 11 110 173 182 QZSS Q1 Q5 193 197 GLONASS R1 R32 R 65 96 0 3 3 11 GPS PASHR The PASHR command alongside the GPZDA command will give all relevant parameters such as time date position velocity direction altitude quality of fix and more As an example the String has the following data format PASHR POS 0 7 202939 00 37 16 28369 N 12157 43457 W 00087 40 070 01 000 3 1 000 10 05 6 03 5 04 3 00 0 DD00 32 Please note tha
39. S GPGSV r a ass ror BT 3 3 11GPS PASHR aaa BT 3 3 12GPS XYZSPeed 38 3 3 13GPS DYNAMic MODE ne ay WE 100 3 3 14GPS DYNAMic MODE 8 Automatic Dynamic Mode So ge Ge ee ar Ay ok at O 3 3 15GPS DYNAMic STATe 2 5 wen 8 3 3 16GPS REFerence ADELay lt float gt lt s r ns gt FS 32767ns 3276708 o S 3 3 17GPS REFerence PULse SAWtooth peo ge 0e a 42 3 3 18GPS RESET ONCE bias e am CR a eee ew ee ee 3 3 19GPS TMODe lt ON OFF RSTSURV gt i a Eo ek we Ega 42 3 3 20GPS SURVey ONCE By ad aes a RS 3 3 21GPS SURVey DURation lt sec gt 43 3 3 22GPS SURVey VARiance lt mm2 gt 48 3 3 23GPS HOLD POSition lt cm cm cm gt 48 3 3 24GPS SURVey STATus La es pa aa es AS 3 3 25GPS INITial DATE lt yyyy mm dd gt D D HE ee ad oe 4 443 3 3 26GPS INITial TIME lt hour min sec gt du o MA 3 3 27GPS SYST SELect GPS SBAS QZSS a GLO BD SAP a ae M do 444 3 3 28GPS JAMlevel dt da Te at AA 3 3 29GPS FWver aaa a a a a a 4 3 3 30GPS A A o ee o oes ct A 3 4 GYRO SUBSYSTEM Soe S dod o PR he at ae a he ee 44 3 4 1 GYRO MODE lt ON OFF gt ene Hah Hone BG ho oe ce Oe O 3 4 2 GYRO TRACE lt int gt 0 255 45 3 4 3 GYRO PORT lt RS232 USB gt 45 3 4 4 GYRO PORT ity
40. S on Labs sync diag meas csac or mac help 2 3 Block Diagram Figure 2 1 depicts the block diagram of the LN Rb GNSDO The unit is built around the MAC Rubidium oscillator which controls a time interval counter with three channels and 20ps resolution The main processor measures the phase offsets between the MAC oscillator the GNSS 1PPS pulse and the Filter Oscillator 1PPS pulse as well as the optional externally supplied 1PPS references The processor then steers the MAC and Crystal Filter oscillators to be phase coherent to each other and to the 1PPS reference signals The two oscillator phase time domains then generate their 10MHZ and 1PPS output signals allowing the user to select which 1PPS and 10MHz outputs are routed to the buffered SMA connector outputs After power on the two oscillator time domains are quickly frequency locked however they may have phase offsets of up to several 100 nanoseconds during warmup and when disturbed by aggressive temperature changes or mechanical shock vibration etc which will slowly be corrected to zero phase offsets by the control loops The phase offsets of the 1PPS references to the MAC oscillator and the MAC oscillator to the filter oscillator can be queried by the serial command SYNC TINT at any time see also Sections 3 6 6 and 3 6 7 Figure 2 1 Block Diagram of the LN Rb GNSDO Buffer GEN 5V Anal and LPF 13dBm SEX e ST Les ee 7V ee ES CA EA A ae Les
41. STem SELect GPS SBAS QZSS GLO GPS JAMlevel GPS FWver GPS 3 3 1 GPS SATellite TRAcking COUNt This query returns the number of satellites being tracked 3 3 2 GPS SATellite ViSible COUNt This query returns the number of satellites PRN that the almanac predicts should be visible given date time and position 3 3 3 NMEA Support The following commands allow the Low Noise Rubidium GNSDO to be used as an industry standard navigation multi GNSS receiver The GPGGA GPGSV GPRMC PASHR and GPZDA NMEA commands comprise all necessary information about the antenna position height velocity direction satellite info fix info time date and other information that can be used by standard navigation applications via the Low Noise Rubidium GNSDO serial interface Once enabled the Low Noise Rubidium GNSDO will send out NMEA sentences on the serial transmit pin automatically every N seconds All incoming serial commands are still recognized by Low Noise Rubidium GNSDO since the serial interface transmit and receive lines operate completely independent of one another For compatibility with existing GPS only products the Low Noise Rubidium GNSDO s NMEA output only uses the GPS NMEA sentence headers GPGGA GPGSV etc regardless of the GNSS systems enabled Also the GPGSV output uses a modified satellite numbering scheme as detailed in Section 3 3 10 to allow all different GNSS system satellites to be differentiated Any combin
42. The manufacturer for connectors J1 and J3 is Hirose A mating housing part number for this connector is available from Digikey and crimp pins are also available from Digikey for different wire sizes http search digikey com scripts DkSearch dksus dll Detail amp name H2025 ND The equivalent part number of the connectors soldered onto the LN Rb GNSDO PCB is Hirose DF11 16DP 2DSA01 2 7 4 Connecting External Loads and Sources The LN Rb GNSDO supports TTL status outputs RS 232 and RS 422 serial interfaces two 1PPS one 5MHz CMOS and various 10MHZ outputs Some of these require 50 Ohm loads others require open ended termination and some do not require any termination The unit also supports two ored 1PPS inputs with 20ps internal resolution for optional locking to an external 1PPS source such as a SAASM GPS receiver The LN Rb PCB also contains two MMCX connectors that are not brought out of the enclosure but may be used with an open lid operation as required These include a 5V CMOS 5MHz output and an additional buffered and isolated and unfiltered 10MHZ output 2 7 4 1 5MHz Internal CMOS output Figure 2 3 shows the 5MHz CMOS MMCX connector internal to the enclosure This signal is not brought out to SMA connectors It is internally driven with a 50 Ohms series termination and should be used with 50 Ohms coax cables that use open ended termination Do not use a 50 Ohms termination on this signal The 1OMHz output of the MAC Rubidium
43. able for display for example 13 24 56 3 5 4 PTIMe TINTerval This query is equivalent to the command synchronization TINTerval 3 5 5 PTIME OUTput lt ON OFF gt This command allows connecting two units together through the serial port with a null modem cable and having the master unit send time and date information to the slave unit The slave unit s 1PPS reference input can also be driven by the master unit s 1PPS output signal by setting the slave unit to external 1PPS sync mode using the sync sour mode next command This allows time synchronization at the nanosecond level between two units which can be useful when operating in GPS GNSS denied environments Sending the command PTIM OUT ON will cause the unit to automatically generate GPS INIT DATE and GPS INIT TIME sentences on the serial port once per second 3 5 6 PTIMe LEAPsecond This command returns the results of the four following queries PTIMe LEAPsecond PENDing PTIMe LEAPsecond ACCumulated PTIMe LEAPsecond DATE PTIMe LEAPsecond DURation 3 5 7 PTIMe LEAPsecond PENDing This command returns 1 if the GPS Almanac data contains a future pending leap second data and 0 if no future leap second is pending or Almanac data is not available The GNSS receiver must have the GPS system enabled for the GPS Almanac to be available 3 5 8 PTIMe LEAPsecond ACCumulated This command returns the internally applied leapsecond offset between GPS time and UTC time as store
44. and the system calculates the required gain and offset parameters to scale the accelerometer output to 1g peak to peak scale and Og indication based on entering these values The GYRO CAL COMPUTE command will query the user for the maximum and minimum indicated g loads The GYRO TRACE 10 command can be used to help establish the g indications on the three different axis to aid in this calibration 3 4 7 GYRO SENS and GPS CAL RESET Used for factory calibration of Gyro subsystem 3 4 8 GYRO GLOAD This command will return the present acceleration on the X Y and Z axis 3 5 PTIME Subsystem The PTIME subsystem regroups all the commands related to the management of the time The list of the commands supported is the following PTIMe DATE PTIMe TIME PTIMe TIME STRing PTIMe TINTerval PTIME OUT put lt onloff gt PTIMe LEAPsecond PTIMe LEAPsecond PENDing PTIMe LEAPsecond ACCumulated PTIMe LEAPsecond DATE PTIMe LEAPsecond DURation PTIME 3 5 1 PTIMe DATE This query returns the current calendar date The local calendar date is referenced to UTC time The year month and day are returned 46 O 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs 3 5 2 PTIMe TIME This query returns the current 24 hour time The local time is referenced to UTC time The hour minute and second is returned 3 5 3 PTIMe TIME STRing This query returns the current 24 hour time suit
45. ation of two GNSS systems can be tracked simultaneously such as GPS with Glonass or QZSS with BeiDou Please note that due to internal double buffering the position direction and speed data is delayed by one second from when the GPS receiver internally reported these to the Low Noise Rubidium GNSDO Microprocessor so the position is valid for the 1PPS pulse previous to the last 1PPS pulse at the time the data is sent one second delay The time and date are properly output with correct UTC synchronization to the 1PPS pulse immediately prior to the data being sent Once set the following commands will be stored in NV memory and generate output information even after power to the unit has been cycled 2015 Jackson Labs Technologies Inc 35 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 3 3 4 GPS PORT lt RS232 USB gt This commands specifies the communication port where the NMEA messages will be sent 3 3 5 GPS PORT This query returns the port where the NMEA messages are sent 3 3 6 GPS GPGGA This command instructs the Low Noise Rubidium GNSDO to send the NMEA standard string GPGGA every N seconds with N in the interval 0 255 The command is disabled during the initial warm up phase This command has the following format GPS GPGGA lt int gt 0 255 GPGGA shows height in MSL Meters this is different from traditional GPS receivers that display height in GPS Meters The difference between MSL and GPS heigh
46. b GNSDO 1PPS signal and the crystal filter 1PPS signal Set higher values for tighter phase following at the expense of frequency stability FIR Filter Depth The SERV FILT configuration option is new and has been introduced in this LN Rb GNSDO It determines the FIR filter depth and therefore the propagation delay of the filter Lower settings 2 to 6 are recommended if loop instability is seen with higher SERV EFCS and SERV PHASECO settings for shorter time constants and larger phase margins in the loop A well compensated Standard Phase Noise option unit will have the shortest loop time constant of all the ordering options and will show performance similar to the plot in Figure 2 16 when experiencing small externally stimulated frequency perturbations Figure 2 16 Standard Noise Option unit recovery with induced 20ppb frequency error Frequency Difference Averaging window Per pixel nE Origin Drift Hz sec Drift Hzimin 1 00E 13 4 51E 12 2 71E 10 200 8 Avg Time s Freq Hz at 1286085 Error 0 100 10 000 000 004 366 996 4 37E 10 0 300 10 000 000 004 079 811 408E 10 1 50E 8 1 10 000 000 004 529 065 4 53E 10 he 3 10 000 000 004 696 377 4 70E 10 10 10 000 000 005 879 337 5 88E 10 30 10 000 000 006 143 244 6 14E 10 1 00E 8 5 00E 9 0 00 0 500 9 1 00E 8 1502 8 200E 8 gt 250E 8 1285218 1285308 1285388 1285475 1285565 1285655 1285735 1285825 1285915 1286008 1286085 Trac
47. co 40 LN Rb vs Fury Unsaved 10 000 MHz 10 2d8m 10 000 MHz 8 9 dBm 0 1005 S ASE 11 3d0hOmOs 2592000 pts TimePod 5330A LN Rb 0 31 filter dacg 50 efcs 2 phaseco 40 LN Rb vs Fury Unsaved 10 000 MHz 10 2d8m 10 000 MHz 8 9d8m 0 1005 1 82E 11 3d0h0mos 2592000pts TimePod 5330A LN Rb 0 31 filter dacg 50 efcs 2 phaseco 40 LN Rb vs Fury Unsaved 10 000 MHz 10 2 dBm 10 000 MHz 8 9 dBm 0 1005 1 83E 11 72h 2571644 pts_ _TimePod 5330A 2015 Jackson Labs Technologies Inc 25 Low Noise Rubidium GNSDO tm User Manual J a ck S on Labs Figure 2 19 compares the performance of the Premium Noise option unit when locked to different GNSS systems and in Position Hold mode versus 3D mobile mode All tests were done with the unit properly warmed up and in a stationary location The light blue trace is Glonass only mobile mode The green trace is GPS only mobile mode The red trace is GPS only in Position Hold mode The magenta trace is Glonass only in Position Hold mode The performance differences between Glonass and GPS systems in Position Hold mode are insignificant in this measurement however there are significant performance advantages in using GPS versus Glonass in 3D mobile mode Figure 2 19 ADEV performance for Various GNSS operating modes Allan Deviation oy t 1639 Tau Sigma Tau 1s 1 76E 12 2s 2 25E 12 1E 10 4s 2 91E 12 8s 3 84E 12 10s 4 15E 12 20s 4 76E 12 40s 4 96E 12 80s
48. constant whenever the unit is in stable conditions to minimize residual noise and to improve the ADEV performance of the filtered output as much as possible for a particular environment SLOW settings are useful in stationary applications whereas MEDIUM or FAST settings are preferred for mobile applications such as in vehicles man packs or aircraft The SERVo MODE query command responds with the current setting If individual servo parameters have been manually configured by the user and differ from the recommended settings shown in section 2 8 then the SERVo MODE query responds with CUSTOM Please note that the LN CSAC and STANDARD TCXO performance ordering options do not support this command Settings are only effective on the PREMIUM and ULTIMATE ordering options of the unit 3 10 3 SERVo STATe This query responds with the current loop parameter settings SLOW MEDIUM FAST or CUSTOM When the SERVo MODE command is configured to AUTO the SERVo STATe query responds with the automatically selected loop parameter setting SLOW MEDIUM or FAST Otherwise the SERVo STATe query response matches the SERVo MODE setting 3 10 4 SERVo LOOP lt ON OFF gt This command enables or disables the servo loop for the selected servo loop With the loop disabled no changes are made to the oscillator frequency control Normally the servo loop is left enabled 3 10 5 SERVo COARSedac This command sets the coarse DAC that controls the EFC volta
49. d only operates on the Rubidium oscillator servo loop 3 6 4 SYNChronization SOURce MODE The Source Mode command allows an optional external 3 3V CMOS 5V CMOS or TTL level 1PPS input to be connected to the Low Noise Rubidium GNSDO board on pin 11 of connector harness J1 or via the RS 422 1PPS input both inputs are ored together internally The unit can use this 2015 Jackson Labs Technologies Inc 49 Low Noise Rubidium GNSDO User Manual J a ck S on Labs external 1PPS input instead of the internal GNSS receiver generated 1PPS Switching to the external 1PPS is either done manually with the EXT command option or automatically with the AUTO command option in case the GNSS receiver loses a GNSS fix for any reason The command has the following format SYNChronization SOURce MODE lt GPS EXTernal AUTO gt This command only operates on the Rubidium oscillator servo loop 3 6 5 SYNChronization SOURce STATE This query shows the state of the external 1PPS synchronization option This command only operates on the Rubidium oscillator servo loop 3 6 6 SYNChronization TINTerval This query returns the difference or Time Interval between the Rubidium or filter oscillator 1PPS output and the loop reference The resolution is 1E 10 seconds This command operates on the currently selected servo loop 3 6 7 SYNChronization TINTerval CSAC This query returns the Time Interval between the Rubidium oscillator 1PPS output and the
50. d in the EEPROM GPS Almanac not received yet or as indicated by the GNSS receiver GPS Almanac is available 2015 Jackson Labs Technologies Inc 47 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 3 5 9 PTIMe LEAPsecond DATE This command returns the date of the pending leap second if any 3 5 10 PTIMe LEAPsecond DURation This command returns the duration of the last minute of the day during a leap second event The returned value is 59 60 or 61 if GPS Almanac data is available and 0 otherwise A response of 60 indicates that no leap second is pending 3 5 11 PTIME This query returns the result of the following queries PTIME DATE PTIME TIME PTIME TINTerval PTIME OUT put PTIME LEAPsecond ACCumulated 3 6 SYNChronization Subsystem This subsystem regroups the commands related to the synchronization of the Low Noise Rubidium GNSDO and filter oscillator with the GNSS receiver or external 1PPS reference Some commands in the SYNC subsystem depend on the currently selected servo loop from the SERVo SELect command see Section 3 10 1 Two phase locked loops are running in parallel and the user must select one of the two phase locked loops prior to interrogation of that particular loop otherwise it may be unclear which loop is providing the data The list of the commands supported for this subsystem is the following SYNChronization HOLDover DURation SYNChronization HOLDover INITiate SYNChronization HO
51. d this offset should be taken into account when calibrating two unit s 1PPS outputs to each other since the lock algorithms will try to steer the Rubidium oscillator for a 0 Ons offset to the UTC 1PPS time pulse and the crystal oscillator to a 0 Ons offset to the Rubidium oscillator phase 3 3 17 GPS REFerence PULse SAWtooth This command returns the momentary sawtooth correction factor that the GNSS receiver indicated 3 3 18 GPS RESET ONCE Issues a reset to the internal GNSS receiver This can be helpful when changing the antenna for example since the GNSS receiver measures the antenna system s C No right after reset and adjusts its internal antenna amplifier gains accordingly It takes approximately 1 minute for locking to commence after a GNSS receiver reset as indicated by the red blinking LED inside the enclosure 3 3 19 GPS TMODe lt ON OFF RSTSURV gt This command selects the Timing Mode of the GNSS receiver If the Timing Mode is OFF the receiver will act as a regular GNSS receiver in 3D mobile mode This mode has to be chosen if the unit is used with a moving antenna If the Timing Mode in ON the timing features of the GNSS receiver are enabled At power up the Hold position stored in NVRAM will be sent to the GNSS receiver and will be used as the reference In order to use this mode the receiver position must be known as exactly as possible Errors in the Hold position will translate into time errors depending on t
52. driven with a sub Ins rise and fall time more than 1GHz equivalent bandwidth and include internal 50 Ohms series termination and should thus be routed in a 50 Ohms coax cable or with short twisted leads These drivers can drive up to 15mA and these signal were thus NOT designed to drive 50 Ohms loads They are designed for an open ended 50 Ohms transmission line or coax cable DO NOT TERMINATE THESE SIGNALS WITH 50 OHMS LOADS USE A MINIMUM LOAD OF 1K OHMS OR HIGHER 2 7 4 5 RS 232 Interfaces Connector J1 has a standard RS 232 level serial interface for SCPI and NMEA control and output and one RS 232 level TX signal driven directly by the GNSS receiver The GNSS receiver output contains binary data and NMEA ASCII data and can be useful if additional GNSS information and low latency NMEA PVT data is required the JLT generated NMEA position and velocity sentences described in section 3 3 3 have a one second latency delay Nominal baud rates are 115 200 baud 8N1 no flow control on the SCPI NMEA port and 38 400 baud 8N1 on the GNSS receiver TX port 2 7 4 6 RS 422 Interface 14 The unit supports one RS 422 connector internally to the enclosure This connector has RS 422 standard differential signalling 3 3V differential signalling with 120 Ohms typical termination A 1PPS output a 1PPS input ored together with the 1PPS CMOS TTL input on connector J1 a 10MHz output and a serial port TX signal are all available in RS 422 format T
53. ducts are not intended for use in medical life saving or life sustaining applications 6 1 3 Exclusive Remedies THE REMEDIES PROVIDED HEREIN ARE THE CUSTOMER S SOLE AND EXCLUSIVE REMEDIES JACKSON LABS TECHNOLOGIES INC SHALL NOT BE LIABLE FOR ANY DIRECT INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES WHETHER BASED ON CONTRACT TORT OR ANY OTHER LEGAL THEORY 82 2015 Jackson Labs Technologies Inc
54. e Notes InputFreq Input Amplitude Reffreq Ref Amplitude Sample interval Freq at 1285708 Duration Acquired Instrument LN Rb 0 31 filter dacg 50 efcs 2 phaseco 40 LN Rb vs Fury Unsaved 10 000 MHz 10 2 dBm 10 000 MHz 8 9 dBm 0 100s 27m 15s 16352 pts TimePod 53304 LN Rb 0 31 filter dacg 50 efcs 2 phaseco 40 LN Rb vs Fury Unsaved 10 000 MHz 10 2 dBm 10 000 MHz 8 9d8m 0 100 10000000 013Hz 2d17h31m34s 2358938pts TimePod 5330A O 2015 Jackson Labs Technologies Inc 23 Low Noise Rubidium GNSDO tm User Manual J a ck S on Labs 2 9 Performance graphs Figure 2 17 shows the typical Allan Deviation of the LN Rb GNSDO with Ultimate Performance Option when locked to GPS in a stable environment and after one week of warmup and burn in The ADEV performance approaches 8E 014 per day when locked to GPS The light blue dashed line is the ADEV performance of the buffered 10MHz output when selected to the MAC oscillator as a driving source and the solid magenta line is the performance when selecting the Ultimate Phase Noise filter OCXO as a source for the buffered output The significant ADEV improvement by the filter OCXO below several 100 seconds averaging time intervals is clearly visible Figure 2 17 Allan Deviation of LN Rb GNSDO when locked to GPS as NEQ BW 5Hz Allan Deviation oy t REF 10MHz House Maser 1 E 10 290ms Acquisition Time gt 2d17h N 7 1 E 11 gt
55. e available as well as an optional RS 422 1PPS input which is ored to the 1PPS CMOS input signal on connector J1 Please note that connector JP2 only contains the differential RS 422 signals and does not contain a ground shield pin It is recommended that the differential RS 422 signal wires are shielded to the enclosure system ground for added noise immunity Leave unused outputs un terminated Connector JP2 has the following pinout Table 2 4 RS 422 connector JP2 pinout Ref Name Function Specification JP2 1 SERIAL OUTN SCPI NMEA Serial RS 422 115 2Kbaud 8N2 Port TX connected in paralell to the RS 232 TX signal JP2 2 SERIAL OUTP SCPI NMEA Serial RS 422 115 2Kbaud 8N2 Port TX connected in paralell to the RS 232 TX signal JP2 3 1PPS INN 1PPS external input RS 422 level ORED with J1 1PPS input Terminated by 120 Ohms to 1PPS INP JP2 4 1PPS INP 1PPS external input RS 422 level ORED with J1 1PPS input Terminated by 120 Ohms to 1PPS INN JP2 5 1PPS OUTN 1PPS OUT RS 422 level either from MAC oscillator or OCXO oscillator software selectable JP2 6 1PPS OUTP 1PPS OUT RS 422 level either from MAC oscillator or OCXO oscillator software selectable JP2 7 10MHz OUTN 10MHz OUT RS 422 level JP2 8 10MHz OUTP 10MHz OUT RS 422 level 12 O 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO tm User Manual Labs 2 7 3 Harness Connectors J1 and J3
56. elect the Coms tab You will see the window shown in Figure 5 2 Select the correct COM port for your computer and set the baud rate to 115 200 parity to None Data Bits to 8 and Stop Bits to 1 Set Flow Control to None Once you have configured the communication parameters press the OK button to close the window 74 2015 Jackson Labs Technologies Inc Jac k S on Low Noise Rubidium GNSDO User Manual Labs 5 4 1 2 Auxiliary parameters After pressing the Options button you can select Auxiliary and set other options or measurements See Figure 5 3 for an example of an auxiliary measurement You will notice that the Aux 1 request string has been set to meas temp lt CR gt and the Log Aux1 box is checked In the area below labeled Traces to be visible on the graph the box Aux 1 is checked and the label CSAC temp has been added Figure 5 2 Setting the communications parameters GPSCon Utility Pro GPSCon COM4 Status Time Map Graph Export Help A PRN EL AZ SS VdmLabs Firmware Rev 2 19 21 44 ra Ts a Paths amp settings FTP Email Coms Time services Auxiliary Aux coms Export graphics Remote control o 3 Port Baud Parity EMO 115200 None r Flow control Data Bits Stop Bits 2 None 8 1 v 7 C XON XOFF RTS CTS start 2 Se Vv Lo N Lo Iv TI Iv Lo 2015 Jackson Labs Technolo
57. elected OFF the raw 10MHZ output of the MAC Rubidium is routed to the buffered outputs N B Please note that for the LN CSAC ordering option this setting always needs to be set to OFF for the unit to function properly For the LN CSAC version of this product the filter oscillator is built into the Microsemi CSAC oscillator and thus the external filter oscillator is not present and cannot be enabled 3 6 17 SYNChronization OUTput FILTer This query returns the Phase Noise filter setting 2015 Jackson Labs Technologies Inc 51 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 3 6 18 SYNChronization HEAIth The SYNChronization HEAIth query returns a hexadecimal number indicating the servo loop s health status Error flags are encoded in a binary fashion so that each flag occupies one single bit of the binary equivalent of the hexadecimal health status flag This query reports the status of the selected servo loop see section 3 10 1 The following system parameters are monitored and indicated through the health status indicator Individual parameters are ored together which results in a single hexadecimal value encoding the following system status information If the phase offset to reference is gt 210ns HEALTH STATUS l 0x4 If the run time is lt 200 seconds HEALTH STATUS l 0x8 If the reference is in holdover gt 60s HEALTH STATUS l 0x10 If the Frequency Estimate is out of bounds HEALTH STATUS l 0x20
58. emium ordering options as well as for the Standard option that uses a TCXO Table 2 6 Recommended Loop Settings Premium Ultimate and TCXO PN Option Usage Slow Time Constant Medium Time Constant Fast Time Constant Standard PN Option Ultimate Premium Ultimate Premium Ultimate Premium SA 31m with TCXO Loop Behavior benign moderate aggressive fast SERV DACGAIN 50 50 50 6 SERV EFCS 2 4 6 10 SERV PHASECO 240 600 2000 2000 SERV EFCD 6 4 2 2 SERV FAST 2 2 1 1 SERV FALE 1800 1800 1800 1800 SERV FILT 20 20 20 2 The commands to control the loop parameters are part of the servo command structure See also the SERVo Subsystem Section 3 10 The individual commands are 22 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO tm User Manual Labs EFC Scale this is the proportional gain of the PID loop Higher values will give quicker frequency convergence and faster locking to the GNSS reference lower loop time constant lower values give less noise EFC Damping overall IIR filter time constant higher values increase loop time constant Setting this value too high may cause loop instability Due to the low noise floor of the time interval counter and references this unit can operate with low settings values of 2 to 4 typically Phase compensation this is the Integral part of the PID loop This corrects phase offsets between the LN R
59. en this dialog If you choose to export the graph you might want to override the TI max setting in force on the screen display You may do this by entering a non zero value into the Override TI control A value of zero causes the export to take the same setting if any as the screen display The export may be done automatically on a timed basis Simply enter a non zero value in seconds to choose an export time interval To manually export in accordance with the settings press the Export button O 2015 Jackson Labs Technologies Inc 79 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 80 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs Certification and Warranty 6 1 Certification Jackson Labs Technologies Inc certifies that this product met its published specifications at time of shipment 6 1 1 Warranty This Jackson Labs Technologies Inc hardware product is warranted against defects in material and workmanship for a period of 1 one year from date of delivery During the warranty period Jackson Labs Technologies Inc will at its discretion either repair or replace products that prove to be defective Jackson Labs Technologies Inc does not warrant that the operation for the software firmware or hardware shall be uninterrupted or error free even if the product is operated within its specifications For warranty service this product must be returned to Jackson
60. enna gain right after power on so for proper operation the GNSS antenna should always be connected prior to turning on the power supply The operator may use Hyperterminal TeraTerm GPSCon Z38xx or any other serial control software to send commands and query status from the unit The third party application GPSCon is recommended for monitoring and controlling the unit This software is available for purchase at the following website http www realhamradio com gpscon info htm JLT also provides a cost free control program called Z38xx and this application program can be downloaded from the following website www jackson labs com index php support The RS 232 serial port on the main 16 pin connector operates in parallel to the enclosure internal USB serial port and commands can be sent and queried independently to and from both connectors English language SCPI commands are available to switch the default serial output of the unit from 8 2015 Jackson Labs Technologies Inc J a ck S O n Low Noise Rubidium GNSDO tm User Manual Labs the RS 232 serial port to the USB port and vice versa Please note that using the standard enclosure shields the internal USB connector from being accessible by the user The PCB will have to be operated outside of the JLT enclosure or the enclosure will have to be modified to allow access to this and a host of other internally accessible connectors 2 6 Accessing internal connections The unit contains va
61. ensitivity GNSS receiver with very fast lock time The unit can either be used in stationary applications using the automatic self survey Auto Survey with Position Hold feature or it can be used in mobile platforms Using Position Hold mode improves timing and frequency accuracy especially in GPS Glonass challenged antenna locations such as under foliage or with strong multipath signals The LN Rb GNSDO is capable of generating industry standard navigation messages see GPS GPGGA GPS GPZDA GPS GPGSV GPS PASHR GPS GSV and GPS GPRMC serial commands in section 3 3 6 that are compatible with most GPS Glonass based navigation software These navigation messages may either be sent out of the RS 232 and RS 422 serial port or the USB serial port 2 7 6 Selecting GNSS Systems The GNSS receiver of the LN Rb GNSDO is capable of receiving several different GNSS systems at the same time providing better performance especially in challenged or denied environments The unit may be operated with GPS SBAS and Glonass simultaneous operation or with GPS or Glonass only operation It can also operate in BeiDou or QZSS only mode where these signals are available The GNSS receiver allows up to two different GNSS systems to be operated at the same time Up to 24 satellites can be received at any given time per GNSS system It is recommended that Glonass operation is only enabled when a Glonass or Glonass GPS compatible antenna system is being used Glonass use
62. ermanently connected to the filter OCXO to maintain the extremely low phase noise floor The two oscillators may have small phase offsets to each other and will have different jitter wander performance levels Both the average phase offsets between the GNSS receiver 1PPS and the Rubidium oscillator as well as the Rubidium oscillator to the OCXO phase offsets can be monitored on a second to second basis in 20ps resolution and this information can be used by a users application to compensate phase offsets to sub nanosecond levels 2015 Jackson Labs Technologies Inc 3 Low Noise Rubidium GNSDO tm User Manual J a ck S O n Labs 1 3 General Safety Precautions The following general safety precautions must be observed during all phases of operation of this instrument Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended use of the instrument Jackson Labs Technologies Inc assumes no liability for the customer s failure to comply with these requirements 1 3 1 Use an approved Antenna Lightning Protector The use of an approved and properly grounded antenna lightning protector on the GNSS antenna is required to prevent damage injury or death in case of a lightning strike 1 3 2 Grounding To avoid damaging the sensitive electronic components in the LN Rb GNSDO always make sure to discharge any built up electrostatic charge to a good gr
63. es the GNSDO is not in holdover a value of 1 indicates the GNSDO is in holdover This command only operates on the Rubidium oscillator servo loop 3 6 2 SYNChronization HOLDover INITiate The SYNC HOLD INTT and SYNC HOLD REC INIT commands allow the user to manually enter and exit the holdover state even while GNSS signals or external IPPS are still being properly received This forced holdover allows the unit to effectively disable locking to the GNSS receiver or external IPPS reference while still keeping track of the state of the 1PPS output in relation to the UTC 1PPS reference When the unit is placed into forced holdover with this command the unit will indicate the time interval difference between the 1PPS output and the GNSS external 1PPS signal with the SYNC TINT CSAC command This allows the user to see the Rubidium oscillator drift when not locked to GPS for testing purposes or to prevent the GNSS receiver from being spoofed and affecting the Rubidium frequency accuracy All other frequency disciplining functions of the unit will behave as if the GNSS antenna or external 1PPS were disconnected from the unit while in this forced holdover state This command only operates on the Rubidium oscillator servo loop 3 6 3 SYNChronization HOLDover RECovery INITiate This command will disable the forced holdover state see the SYNC HOLD INIT command The unit will resume normal GNSS locking operation after this command has been sent This comman
64. ewhaven Display PN NHD 0216K1Z NSW BBW L The LCD connector drives the LCD directly The 5V power pin can be used to drive the LCD s backlighting and additional external circuitry if the current draw is limited to 0 15A or less Contrast of the LCD is adjusted via software command Figure 2 4 shows the LCD connected to an open lid unit A schematic showing the connections from the LN Rb GNSDO to the LCD panel is shown in Figure 2 5 Figure 2 4 LCD display connection TUN OZE S Y LOVES 126 9 SHOR SN OY9RO0DWPOLL AN AS SBRYOA DP ndul soyeW198O wnipiany SINE 1L OSEVY 060 s0quinN ped wsevs wy v Table 2 5 LCD connector J3 pinout PIN NAME 1 CONTRAST 2 5V 3 GND 4 LCD_RS 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO tm User Manual Labs 5 For factory use only 6 LCD_RDWR 7 For factory use only 8 LCD_ENABLE 9 For factory use only 10 LCD_DATA4 11 For factory use only 12 LCD_DATAS 13 For factory use only 14 LCD_DATA6 15 For factory use only 16 LCD_DATA7 Figure 2 5 LCD display connections 5V To LCD DISPLAY CONTRAST J3 LCD RDWR 1 3 4 5 6 7 a LCD ENABLE 0 2 1 2 3 LCD_RS 4 5 6 7 X X x 9 10 LCD_DATA4 x x 11 12 LCD DATAS x 8 x 13 14 LCD DATA6 x 9 x 15 16 LCD DATA7 x 10 11 12 13 14
65. ge on the filter servo loop This command is only available when the filter servo loop is selected The filter servo control loop automatically adjusts this setting The user should not have to change this value but it is useful to establish filter loop lock time constants by artificially applying an incorrect steering voltage to the filter oscillator and monitoring the subsequent loop behavior This command has the following format SERVo COARSedac lt int gt 0 225 3 10 6 SERVo DACGain This command is used for factory setup 2015 Jackson Labs Technologies Inc 59 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 3 10 7 SERVo EFCScale Controls the Proportional part of the PID loop for the selected servo loop Typical values are 0 7 to 6 0 Larger values increase the loop control gain reducing the loop time constant at the expense of increased noise while locked Setting this value too high can cause loop instabilities This command has the following format SERVo EFCScale lt float gt 0 0 500 0 3 10 8 SERVo FiLTerlength Sets the Low Pass pre filter effectiveness for the time interval counter data for the selected servo loop Values from 2 to 20 are valid Larger values result in less noise at the expense of phase delay and may cause loop instability This command has the following format SERVo FILTerlength lt int gt 2 20 3 10 9 SERVo EFCDamping Sets the Low Pass post filter effectiveness for the EFC cont
66. gies Inc 75 Low Noise Rubidium GNSDO User Manual J a C ks on Labs Figure 5 3 Auxiliary parameters window Paths amp settings FTP Email Coms Time services Auxiliary Aux coms Export graphics Remote control near ima 2nd port error request string SYST ERR lt CR gt 7 Enable second serial port 2nd port OK prompt scpi lt SPC gt gt lt SPC gt Wildcard for any character type is 7 Wildcard for numeric character is Camiage retum is 2nd port error prompt E HHH gt lt SPC gt lt CR gt Linefeed is lt LF gt Aux request string meas temp lt CR gt M Log Aux1 or Log Max SS Aux2 request string DATAE12 lt CR gt T Log Aux2 or Log Min SS A request sting DATAE4 lt CR gt top Awd Peete or WF EFC Max Filter Fit coeff o Paio P ee a rpe E _ rf e ce vou Aol ff fp E fe 5 4 1 3 Other options The other tabs in the options window can be selected and you can set whatever options you need such as paths for logging or exporting graphics 76 O 2015 Jackson Labs Technologies Inc J a ck S O n Low Noise Rubidium GNSDO User Manual Labs 5 4 2 Sending manual commands to the receiver You can send SCPI commands manually by using the drop down box under the display window as shown in Figure 5 4 Care must be taken when sending these commands so be sure that the command that you select is supported by the LN Rb GNSDO Once yov ve selected the command you can press Send t
67. h other The internal RTC is driven by the highly stable Rubidium oscillator s 1OMHz signal and thus has very high accuracy 3 3 27 GPS SYST SELect GPS SBAS QZSS GLO BD This command selects the GNSS systems that are enabled in the GNSS receiver and are used to generated the timing and positioning information for the NMEA data and to generate the 1PPS reference for the GNSDO The command is followed by any combination of the currently supported GNSS system abbreviations GPS SBAS QZSS BD BeiDou and GLO GLONASS 3 3 28 GPS JAMlevel The GNSS receiver will detect and flag jamming interference with levels ranging from 0 no jamming to 255 strong jamming Any level exceeding 50 in combination to loss of GNSS lock will cause a SYNC HEALTH 0x800 event to be flagged and the unit to disable the LOCK OUT OK signal on connector J1 3 3 29 GPS FWver This command returns the firmware version used inside the GNSS receiver itself 3 3 30 GPS This query displays the configuration position speed height and other relevant data of the GNSS receiver in one convenient location 3 4 GYRO SUBSYSTEM The following Gyro commands are supported GYRO MODE lt ON OFF gt GYRO TRACE lt int gt 0 255 GYRO PORT lt RS232 USB gt GYRO PORT GYRO CALibrate lt float float float float float float gt GYRO CALibrate COMPute GYRO CALibrate RESET GYRO SENSitivity lt float float float gt GYRO GLOAD 44 2015 Jackson Lab
68. he commands related to the adjustment of the Rubidium and filter oscillator servo loops SERVo SELect lt CSAC FILTer gt SERVo MODE lt SLOW MEDium FAST AUTO gt SERVo STATe SERVo LOOP lt ON OFF gt SERVo COARSEDAC lt int gt 0 255 SERVo DACGain lt float gt 0 1 10000 SERVo EFCScale lt float gt 0 0 500 0 SERVo EFCDamping lt int gt 2 4000 SERVo TEMPCOmpensation lt float gt 4000 0 4000 0 SERVo AGINGcompensation lt float gt 10 0 10 0 SERVo PHASECOrrection lt float gt 500 0 500 0 SERVo 1PPSoffset lt int gt ns SERVo TRACe PORT lt RS232 USB gt SERVo TRACe lt int gt 0 255 SERVo FASTlock lt 1 20 gt SERVo FALEngth lt 100 20000 gt SERVo 3 10 1 SERVo SELect lt CSAC FiLTer gt 58 The Low Noise Rubidium GNSDO has two separate servo loops one loop for the MAC Rubidium being disciplined by the GNSS receiver and the second loop for the filter oscillator being disciplined by the MAC Rubidium This command selects the enabled servo loop for the SCPI interface commands The selected servo loop for the RS 232 and USB interfaces can be configured independently Several of the SYNC subsystem commands and all of the SERVO subsystem commands will act on the currently selected servo loop The CSAC option selects the Rubidium oscillator loop that locks to the GNSS receiver or external 1PPS reference to the atomic oscillator and the FIL Ter option selects the filter oscillator loop that lock
69. he satellite constellation The Hold position can be set manually by the user or can be the result of a position Auto Survey executed by the GNSS receiver If the Timing Mode is set to RSTSURV the GNSS receiver will start an Auto Survey every time the unit is powered on and following the Survey sequence the GNSS receiver will run with the timing features enabled Once in Position Hold mode the antenna location should be held completely stationary 42 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs 3 3 20 GPS SURVey ONCE This command starts an Auto Survey At the end of the Survey the calculated Hold position will be stored in NVRAM The Survey parameters can be set with the command GPS SURVey DURation and GPS SURVey VA Riance 3 3 21 GPS SURVey DURation lt sec gt This command sets the Survey minimal duration 3 3 22 GPS SURVey VARiance lt mm22 gt This command specifies the minimum variance of the average position computed during the Survey This minimum value is used as a threshold under which the GNSS receiver can stop the Survey The GNSS receiver will stop the Survey when the minimal duration has been reached and the variance of the average position is under the specified minimum variance 3 3 23 GPS HOLD POSition lt cm cm cm gt This command allows the user to specify manually the exact position of the antenna This command will overwrite the Hold position in NVRAM A
70. he three output signals expect 120 Ohms termination and the 1PPS RS 422 input includes a 120 Ohms internal terminator Signal routing should be done with 120 Ohms differential wiring and ground shielding is recommended around the differential pairs for additional noise immunity 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO tm User Manual Labs 2 7 4 7 1PPS CMOS TTL Input A 1PPS CMOS TTL input is available on pin 11 of the main 16 pin connector J1 This signal is terminated with a 1K Ohms termination resistor Levels can be 2 5V 3 3V or 5V rising edge with at most 15ns rise time recommended The unit can be instructed to lock to this external 1PPS signal with the SCPI command SYNC SOUR MODE EXT as described in section 3 6 4 It is recommended that the external 1PPS signal has similar or better stability than a late generation GPS receiver to minimize adding noise to the Rubidium oscillator stability It can be used to phase lock the units 1PPS and 10MHZ outputs to an external source or to periodically say once per year re calibrate the MAC Rubidium oscillator frequency accuracy 2 7 5 Connecting the GPS Glonass Antenna Connect the GPS Glonass antenna to connector J6 The unit will work with a GPS Glonass or combined GPS Glonass active antenna Caution use a Lightning Arrestor on your Antenna setup Use an amplified antenna that is 5V compatible The LN Rb GNSDO GPS receiver is a 72 channel high s
71. ise Rubidium GNSDO has two serial ports that can be used simultaneously for accessing the SCPI Standard Commands for Programmable Instrumentation subsystem by using a host system terminal program such as TeraTerm Pro or HyperTerminal By default the terminal settings are 115200 8N1 no flow control There are a number of commands that can be used as listed below Most of these are identical or similar to Symmetricom Agilent 58503A commands To get a listing of the available commands send the HELP query This will return a list of all the available commands for the Low Noise Rubidium GNSDO Commands can be entered in either caps or lower case and only the characters listed in caps in the below command reference need to be typed in Additional information regarding the SCPI protocol syntax can be found on the following web site http www ivifoundation org scpi A basic familiarity with the SCPI protocol is recommended when reading this chapter As a Quick Start the user may want to try sending the following commands to the unit syst stat help gps sync diag csac 2015 Jackson Labs Technologies Inc 33 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 3 2 General SCPI Commands 3 2 1 IDN This query outputs an identifying string The response will show the following information lt company name gt lt model number gt lt serial number gt lt firmware revision gt 3 2 2 HELP This query returns a lis
72. ksony Jac son Low Noise Rubidium GNSDO User Manual cument 80200526 Low Noise Rubidium GNSDO tm User Manual Copyright 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GPSDO User Manual Labs 1 Introduction 1 1 Overview 1 2 Operating Principles 1 3 General Safety Precautions 1 3 1 Use an approved Antenna Lightning Protector 1 3 2 Grounding 1 3 3 Power Connections 1 3 4 Environmental Conditions ARR A PR OU a 2 GNSDO Quick Start Instructions 5 2 1 Ordering Options 5 2 2 Powering Up the Unit fe Gyo Ge a oe ok oe ok OD 2 3 Block Diagrama 2 msg sh Viga amp ae GE mu we a we a 6 2 4 Mechanical Drawing 7 2 5 Operating the unit 8 2 6 Accessing internal connections 9 2 7 Major Connections Be As ne i ey er ee i a a e ee 2 7 1 Power Harness Pinning cc Gg oe a Bb we ge amp O 2 7 2 RS 422 Connector JP2 12 2 7 3 Harness Connectors J1 and J3 13 2 7 4 Connecting External Loads and Sources 18 2 7 4 1 5MHz Internal CMOS output 13 2 7 4 2 LOCK _OK Output 18 2 7 4 3 10MHz Sine Wave Outputs 13 2 7 4 4 CMOS 1PPS Outputs 14 2 7 4 5 RS 232 Interfaces
73. llel with switch S1 Auto Survey J1 7 LOCK_OK_OUT 3 3V constant 3 3V CMOS output can drive indicates that no up to 5mA series terminated internal events are by 33 Ohms pending the hardware is ok and the MAC and OCXO are locked to GNSS A 0 25Hz blinking indicates GNSS holdover with OCXO lock to Rubidium OV indicates an EVENT or NO LOCK warmup J1 8 RX_232 RS 232 receive data RS 232 level 115 2KB 8N1 J1 9 TX_232 RS 232 transmit data RS 232 level 115 2KB 8N1 J1 10 GPS_RS232 Raw NMEA output RS 232 level 38 4KB 8N1 from GPS receiver in RS 232 level format J1 11 1PPS_IN External alternate TTL 3 3V and 5V CMOS 1PPS input compatible J1 13 1PPS OUT 5V CMOS 1PPS 5V CMOS either from MAC output oscillator or OCXO oscillator software selectable series terminated with 50 Ohms Table 2 2 shows the cable harness J1 pinout Table 2 2 J1 pinout PIN NAME 1 ENTER_ISP 2 RST_IN 3 GND 2015 Jackson Labs Technologies Inc Jackson m Low Noise Rubidium GNSDO tm User Manual 4 GND 5 LCD_KEY 6 GND 7 LOCK_OUT_OK 8 RX RS 232 9 TX RS 232 10 GPS_RS232 11 1PPS_IN 12 GND 13 1PPS_OUT 14 GND 15 8V to 36V 16 8V to 36V Table 2 3 Miscellaneous connectors Ref Name Function Specification Pinning J2 ISP RESET ISP RESET jumper GND pin 1or 3 to activate J2 1 ISP J2 2 GND J2 3 RST J4 GNSS USB Optional USB USB
74. ltimate Performance option a level of performance that used to require combining various different reference sources to achieve The unit is available with a temperature range of 40 C to 70 C and greater than 200 000 hours MTBF The unit is packaged in a precision machined gold plated Aluminum enclosure and can be ordered with optional conformal coating 2015 Jackson Labs Technologies Inc 1 Low Noise Rubidium GNSDO tm User Manual J a C ks on Labs Figure 1 1 Low Noise Rubidium GNSDO The LN Rb GNSDO enclosure has three separate 10MHz Sine Wave SMA outputs two CMOS 1PPS outputs an optional external 1PPS input an antenna connector with internal antenna bias power supply and a sophisticated serial control interface with NMEA output capability The LN Rb GNSDO board internally to the enclosure provides an additional 10MHz Sine output a 5MHz CMOS output LCD interface RS 422 interface including 10MHz and 1PPS in and out and a USB serial link for command and control and is powered from an aviation bus compatible power supply that operates from 8V up to 36V with reverse polarity protection and can thus be directly connected to an aircraft s or vehicles 12V or 24V power bus For long term Stratum 1 frequency accuracy and constant calibration the LN Rb GNSDO includes an extremely high performance GNSS receiver that can acquire and track up to 72 GNSS signals down to a state of the art 167dBm allowing indoor reception and sup
75. m filter oscillator warmup 1 Holdover 2 Locking Rubidium filter training 4 Value not defined 5 Holdover but still phase locked stays in this state for about 100s after GNSS lock is lost 6 Locked and GNSS active O 2015 Jackson Labs Technologies Inc 61 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 3 10 16 SERVo FASTlock The FASTlock command enables the FASTLOCK mode and sets its gain parameter for the selected servo loop Fastlock works by momentarily multiplying the EFCScale gain to a value determined by this SERVo FASTlock parameter Gain values of 1x to 20x can be set with a gain of 1x 100 effectively disabling the FASTLOCK feature By selecting gain values of gt 1 the PLL loop parameter Proportional gain SERV EFCscale will be increased after power on thus increasing loop aggressiveness and reducing the PLL lock time and the loop time constant It is not desirable to maintain a high loop gain for longer than necessary to lock the PLL since high loop gains come at the expense of increased phase noise reduced short term stability The FASTLOCK mechanism will automatically reduce the FASTLOCK gain over a period of time specified by the SERVo FALEngth command during which time the FASTLOCK gain is slowly decreased from its initial value to 1 0x Setting the FASTLOCK gain to 2 for example will result in the Proportional gain value stored in the SERVo EFCscale parameter to be multiplied by 2x initially after power
76. m regroups the queries related to parameters that are measured on board the Low Noise Rubidium GNSDO 3 8 1 MEASure TEMPerature Displays the PCB temperature inside the MAC Rubidium and around the filter oscillator 54 O 2015 Jackson Labs Technologies Inc J a C Kk S O n Low Noise Rubidium GNSDO User Manual Labs 3 8 2 MEASure VOLTage Displays the MAC Rubidium oscillator internal TCXO steering voltage 3 8 3 MEASure CURRent Legacy SCPI command instead of OCXO current this command displays either the internal Rubidium temperature or PCB temperature around the filter oscillator This query reports the value for the selected servo loop see section 3 10 1 3 8 4 MEASure POWersupply Displays the power supply input voltage 3 8 5 MEASure The MEASure query returns the results of the following four queries MEASure TEMPerature MEASure VOLTage MEASure CURRent MEASure POWersupply 3 9 SYSTEM Subsystem This subsystem regroups the commands related to the general configuration of the Low Noise Rubidium GNSDO The list of the commands supported for this subsystem follows SYSTem COMMunicate SERial ECHO lt ON OFF gt SYSTem COMMunicate SERial PROmpt lt ON OFF gt SYSTem COMMunicate SERial BAUD lt 9600 19200 38400 I 57600 115200 gt SYSTem FACToryreset ONCE SYSTem ID SN SYSTem ID HWrev SYSTem LCD CONTrast 0 1 0 SYSTem LCD CONTrast SYSTem LCD PAGE 0 8 SYSTem LCD PAGE SYSTem COMMunicate USB B
77. nc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs Rubidium or filter oscillator phase is slowly and continuously adjusted toward Ons offset to the reference 1PPS while the phase difference is less than the THReshold phase limit The default setting is 220ns allowing a drift of up to 220ns Reaching this selected threshold will cause a jam sync phase normalization to be initiated which will also cause the SYNC HEALTH Status to indicate 0x200 and the Green LED to be turned off for several minutes This command operates on the selected servo loop see section 3 10 1 3 6 20 SYNChronization This query returns the results of the following queries SYNChronization SOURce MODE SYNChronization SOURce STATE SYNChronization OUTput 1PPS RESET SYNChronization OUTput 1PPS DOMAIN SYNChronization LOCKed SYNChronization HOLDover STATe SYNChronization HOLDover DURation SYNChronization FEEstimate SYNChronization TINTerval SYNChronization TINTerval THReshold SYNChronization OUTput FILTer SYNChronization HEAIth 3 7 DIAGnostic Subsystem This subsystem regroups the queries related to the diagnostic of the CSAC The list of the commands supported for this subsystem is as follows DIAGnostic ROSCillator EFControl RELative DIAGnostic ROSCillator EFControl ABSolute DIAGnostic ROSCillator EFControl ABSolute CSAC DIAGnostic ROSCillator EFControl ABSolute FILTer DIAGnostic LIFetime COUNt 3 7 1 DIAGnostic ROSCillato
78. ng is ignored as the unit does not expect any motion on the antenna In this case the dynamic state as programmed into the GNSS receiver is set to STATIONARY independent of the user selection for GPS DYNAMIC MODE The current dynamic state being applied to the GNSS receiver can be queried with the command GPS DYNAMIC STATE Please note that this command syntax has changed from previous products such as the FireFly ILA GNSDO units which did not support Position Hold Auto Survey modes 3 3 14 GPS DYNAMic MODE 8 Automatic Dynamic Mode Automatic Dynamic Mode allows the Low Noise Rubidium GNSDO firmware to automatically configure the GNSS receiver Kalman filter parameters based on actual mission velocities and motion profiles drastically improving overall performance The unit will try to set the GNSS receiver to the optimal setting for any given velocity The unit is able to set 7 different modes as shown in section 33 13 The following table shows the Dynamic mode the unit will program into the GNSS receiver when Automatic Mode is selected Dynamic Mode 8 Table 3 2 Auto Dynamic Mode Switching Rules Velocity Threshold Selected Dynamic Model Fallback to lower setting 0 2 knots Stationary none gt 2 knots Pedestrian lt 1 knots gt 10 knots Automotive lt 8 knots gt 60 knots and gt 400 Feet min Airborne 1g lt 50 knots climb descent gt 150 knots Airborne 2g lt 130 knots gt 240 knots Airborne 4g lt 210 knots
79. o send it to the LN Rb GNSDO Figure 5 4 Sending manual commands Status Time Map Graph Export Help About VdmLabs Firmware Rev 2 19 A Life F1 Not Tracking 3 5 E PRN El Az EEE 15 2 147 Stop 18 7 201 26 4 118 Hide UTC 22 56 52 28 Oct 2018 LAT N 37 16 52 397 LON W 121 59 15 645 74 16 m HSL OCXO Current OK EFC OK GPS Receiver Status 3D Fix 1PPS SOURCE MODE GPS 1PPS SOURCE STATE GPS GPSDO Status Locked Send 22 39 10 28 10 10 UTC Receiver timeout 3 LOG 3 22 33 20 28 10 10 UTC Receiver timeout Mite DIAG TOG READ L 22 39 29 28 10 10 UTC Receiver timeout ML DIAG ROSC EFC ABS 22 39 39 28 10 10 UTC Receiver timeout O DIAG ROSCEFC REL 22 39 48 28 10 10 UTC Receiver timeout F TitolDIAGTEMP 5 22 33 58 28 10 10 UTC Receiver timeout DIAG TEST RES 22 40 07 28 10 10 UTC Receiver timeout 22 40 23 28 10 10 UTC Receiver timeout Y Log a E Cont EPS INIT DATE lo mo day 22 42 17 28 10 10 UTC Receiver timeout ontil EAU mo GPS INIT POS N deg min sec W deg min sec elev Last error E 5 4 3 Use of the mouse in graph mode Refer to Figure 5 5 for the following description In graph mode the span of the graph may be set using the span setting Alternatively the start and or stop time of the graph may be locked using the mouse Set the start time by left clicking on the desired start point If you wish the stop time may also be locked by right clicking the de
80. ocity It returns a value between 0 and 7 which correspond to one of the dynamic models defined in the Table in section 3 3 14 This state can be different from the user selected Dynamic model mode for two reasons e if the dynamic mode is set to 8 Automatic mode the state will reflect the dynamic model being applied to the GNSS receiver depending on actual vehicle dynamics e if the GPS Timing Mode is set to ON or to RSTSURV the dynamic state will always be set to 1 Stationary 3 3 16 GPS REFerence ADELay lt float gt lt s ns gt 32767ns 32767ns The ADELay command allows bi directional shifting of the 1PPS output in relation to the UTC 1PPS reference in one nanosecond steps This allows antenna cable delay compensation as well as retarding or advancing the 1PPS pulse arbitrarily to calibrate different units to each other for 2015 Jackson Labs Technologies Inc 41 Low Noise Rubidium GNSDO User Manual J a ck S on Labs example Typical antenna delays for a 30 foot antenna cable with 1 5ns per foot propagation delay would be compensated with the following command GPS REF ADEL 45ns This command can be used to fine tune different units to have co incident 1PPS pulse outputs Please note that during normal operation the 1PPS pulse may wander around the UTC 1PPS pulse while the unit is tracking the GNSS signals The present offset between the 1PPS output and the UTC 1PPS signal can be queried with the command SYNC TINT an
81. om at the following URL http www realhamradio com gpscon buy now htm Important note On newer faster computers running Windows 7 or 8 GPSCon may not acquire data correctly Try running GPSCon in Windows XP compatibility mode and as an administrator If you encounter problems it is recommended that you install GPSCon on a slower computer using Windows XP 5 2 Z38xx Utility If the GPSCon utility is not available you may use the Z38xx utility The Z83XX utility is a PC monitor program for GNSS Disciplined References GNSDO which communicate using the SCPI Standard Commands for Programmable Instrumentation Protocol It is available on the Jackson Labs Technologies Inc website under the Support tab http www jackson labs com assets uploads main Z38X X_download zip The program provides real time monitoring of the operation of the GNSDO including status information GNSS satellite information timing and control information holdover prediction reference Allan Variance and even a UTC clock with second accuracy It also displays various logs and stores all measurements on file for later analysis 5 3 GPSCon Installation Follow the directions that come with GPSCon for installing the utility on your computer 2015 Jackson Labs Technologies Inc 73 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 5 4 Using GPSCon The GPSCon utility has a help file that should be consulted in order to get the full functionalit
82. on Figure 2 13 This page displays the following Navigation status Course in degrees Speed knots operating mode and altitude feet Figure 2 13 Navigation display page e GNSS UTC Time Figure 2 14 This page displays the following UTC GNSS Time information UTC time hh mm ss GNSS time hh mm ss and leapsecond offset seconds Figure 2 14 GNSS UTC Time display page 2015 Jackson Labs Technologies Inc 21 Low Noise Rubidium GNSDO tm User Manual Jackson e Survey status Figure 2 15 This page displays the status NOT ACTIVE ACTIVE or VALID survey duration seconds and variance mm of the position survey Figure 2 15 Survey status display page 2 8 Loop parameter adjustment All loop parameters can be controlled via the serial ports The firmware typically offers three different phase loop time constants for the filter oscillator loop to accommodate different mission scenarios stationary versus mobile steady state operation versus power cycling etc These time constants determine the behavior of the unit during steady state operation and when a frequency error is induced into the filter oscillator by adverse environmental effects such as tilt shock of the unit or due to thermal shocks The loop adjustments typically include a SLOW MEDIUM FAST time constant options set with the SERVo MODE command described in Section 3 10 2 The following table shows typical parameter settings for the Ultimate and Pr
83. on This dynamic gain is slowly reduced until the gain is back to 1 0x the value stored in the SERVo EFCScale parameter For example if we set SERVo FASTlock to 2 and SERVo FALEngth to 3600 and SERVo EFCScale is set to 0 7 then initially the unit will multiply the EFCscale by 2x and an effective EFCscale value of 1 4 is applied to the PLL loop This increased gain value difference will be reduced every second by 1 3600 so that the gain after two seconds would be 1 3998 until after 3600 seconds the gain has been reduced back to its long term value of 0 70 as stored in the SERVo EFCscale parameter Disabling the FASTLOCK mode is accomplished by setting the SERVo FASTlock to 1 This will set the dynamic gain to 1 0 effectively disabling the fastlock feature This command has the following format SERVo FASTlock lt int gt 1 20 3 10 17 SERVo FALEngth This command adjusts the length of time during which the FASTLOCK feature is active please see the command SERVo FASTlock 3 10 16 above The length parameter can be set from 100 seconds to 20 000 seconds The Dynamic FASTLOCK gain is slowly reduced until it reaches a gain of 1 0 after the FALEngth period of seconds During this time the PLL loop gain is increased by the amount specified in the SERVo FASTlock parameter which will result in a faster initial phase lock to UTC after power on while giving the lowest possible noise floor best short term stability during normal operation
84. on and very slowly to keep the MAC 1PPS reference in phase lock with the GNSS generated 1PPS signal This allows a very close tracking of the UTC 1PPS signal to within tens of nanoseconds anywhere in the world out performing even the best free running Atomic References in the long run Selection of the GNSS system being activated allows tracking various different world wide UTC time systems with UTC NIST being a default UTC reference With this software PLL system the short term instability of the GPS receiver is filtered by the MAC while the MAC s long term drift is removed by the GNSS receiver resulting in both a very good short term as well as tightly UTC phase locked long term performance The 10MHz VCXO used in the MAC oscillator exhibits fairly high phase noise and numerous spurs on the output of the MAC A dedicated ovenized phase noise cleanup oscillator is phase locked to the MAC 10MHz output with selectable time constants loop bandwidth which allows generation of world class phase noise and ADEV performance while maintaining the superior drift performance and stability of the MAC Rubidium Spurs are also removed to eliminate phantom targets in radar applications for example Software commands allow either the cleanup phase noise filter or the raw 10MHz output of the MAC to be selected on the unfiltered SMA connector as well as selection of the 1PPS time domain from the MAC or the Crystal OCXO Two additional SMA connectors are p
85. oper calculation of GPS time from UTC time as indicated by other messages as well as proper handling of Leapsecond events Use the following format to generate the velocity vector every N seconds with N in the interval 0 255 GPS XYZSPeed lt int gt 0 255 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs 3 3 13 GPS DYNAMic MODE This command allows the user to select the dynamic motion model being applied to the Kalman filters in the GNSS receiver This allows for larger amounts of filtering for lower velocity applications effectively reducing noise and multipath interference Applications with high acceleration or velocity can now be used with fast filter settings to allow for the most accurate GNSS coordinates to be provided in high dynamic applications such as Jet aircraft Doppler tracking is enabled in all airborne modes as Carrier Phase tracking is very difficult to achieve in high velocity applications The GNSS receiver will perform Carrier Phase tracking for non airborne modes The command has the following syntax GPS DYNAMic MODE lt int gt 0 8 Sending the following command to the LN Rb GNSDO will select a stationary GNSS dynamic model for example gps dynam mode 1 The following table lists all available modes Table 3 1 Supported Dynamic GNSS Operating Modes Value Model Application Portable Recommended as a default setting
86. orrection mechanism Larger values result in shorter time constants 60 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs Loop instability may result if the parameter is set too high Typical values are 1 0 to 2000 depending on the loop being selected This command has the following format SERVo PHASECOrrection lt float gt 2000 0 2000 0 3 10 13 SERVo 1PPSoffset This command is not supported on the LN Rb GNSDO 3 10 14 SERVo TRACe PORT This command selects the serial port for trace debug output This command has the following format SERVo TRACe PORT lt RS232 USB gt 3 10 15 SERVo TRACe This command sets the period in seconds for the debug trace for the selected servo loop Debug trace data can be used with Ulrich Bangert s Plotter utility or Excel to show UTC tracking versus time etc This command has the following format SERVo TRACe lt int gt 0 255 An example output is described here 08 07 31 373815 60685 32 08 2 22E 11 14 10 6 0x54 date 1PPS Count OCXO Fine DAC or MAC Steering UTC offset ns Frequency Error Estimate Sats Visible Sats Tracked Lock State Health Status Please see the SYNChronization HEAIth command for detailed information on how to decode the health status indicator values The Lock State variable indicates one of the following states Table 3 3 Lock Status Indications Value State 0 Rubidiu
87. ound source such as power supply ground This should be done before handling the circuit board or anything connected to it i e the GNSS antenna 1 3 3 Power Connections Make sure to connect the DC power to the device following the polarity indicated in Section 2 6 1 3 4 Environmental Conditions This instrument is intended for indoor use The use of a properly installed GNSS Antenna Lightning Protector is required It is designed to operate at a maximum relative non condensing humidity of 95 and at altitudes of up to 50 000 meters Refer to the specifications tables for the dc and ac mains voltage requirements and ambient operating temperature range This product consumes more than 5W of power in steady state conditions and will heat up accordingly Sufficient cooling of the backplate is required to maintain operation at or below 70 C on the backplate 4 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO tm User Manual Labs GNSDO Quick Start Instructions 2 1 Ordering Options The LN Rb GNSDO is available in four off the shelf configurations depending on performance and pricing requirements These options are Ultimate Phase Noise ADEV Thermal Stability and Holdover performance SA35 m e Premium Phase Noise ADEV Thermal Stability and Holdover performance SA33 m Standard Phase Noise ADEV Thermal Stability and Holdover performance SA31 m e Low Power Low Noise Cesium Vapor Cell
88. page displays the following Rubidium Vapor Cell status Heater Power Cell Temperature in C and TCXO Steering Voltage OV to 2 5V The TCXO is locked to the Rubidium Vapor Cell via a Phase Locked Loop and generates the 1OMHz output frequency TI and FE Figure 2 12 TI in the left upper row is the time interval offset in nanoseconds between the internal MAC oscillator phase and UTC phase as generated by the GNSS receiver The right upper row displays the TI interval in nanoseconds between the MAC Rubidium phase and the OCXO phase The PLL control loop will try to zero this offset over time as the unit follows UTC via the Satellite transmissions FE indicates the Frequency Error Estimate of the relevant loop which is a unit less number and is estimated by comparing the UTC MAC and MAC OCXO phase offset from 1000 seconds ago to the present phase offsets This is similar to the Allan Deviation number for a measurement interval of 1000 seconds Smaller numbers are better but numbers below 1E 012 are below the noise floor of the instrument A number of 4E 012 for example can be loosely interpreted to be a phase drift of the 1OMHz and 1PPS outputs of 4 picoseconds per second averaged over 1000 seconds as compared to the UTC master clock re created by the GNSS receiver 20 2015 Jackson Labs Technologies Inc Jac k S on Low Noise Rubidium GNSDO tm User Manual Labs Figure 2 12 Tl and FE display page ha ca mas _ e Navigati
89. ports the simultaneous reception of various GNSS systems such as GPS Glonass BeiDou QZSS SBAS and Galileo Galileo with a firmware update when the constellation becomes available The LN Rb GNSDO also includes a high performance triple time interval counter that can measure the internally generated 1PPS signal from the GPS receiver or an externally supplied 1PPS reference signal as well as the phase difference between the Rubidium oscillator and the Crystal Filter oscillator all simultaneously with a resolution of 20 picoseconds per second The Rubidium oscillator is phase locked to either of the two 1PPS signals with better than 0 2ns average phase accuracy typically and the Crystal Filter oscillator can be phase locked to better than 0 3ns average steady state phase accuracy to the Rubidium reference typically Software compensation measures residual aging thermal and g sensitivity errors of the oscillators and applies electronic 2 O 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO tm User Manual Labs compensation to reduce these residual errors This error compensation can improve performance especially in GNSS denied environments and allows monitoring of the Rubidium and Crystal oscillator health and detection of performance abnormalities in the system A complex Built In Self Test BIST system constantly monitors the units health and performance and issues a TTL alert as well as pushed or polled status
90. r EFControl RELative This query returns the Electronic Frequency Control EFC output value of the rubidium or filter oscillator It returns a percentage value between 100 to 100 This query returns the value for the selected servo loop see section 3 10 1 2015 Jackson Labs Technologies Inc 53 Low Noise Rubidium GNSDO User Manual J a ck S on Labs 3 7 2 DIAGnostic ROSCillator EFControl ABSolute This query returns the Electronic Frequency Control EFC steering value of the Rubidium or filter oscillator in parts per trillion 1E 012 or Volts respectively This query returns the value for the selected servo loop see section 3 10 1 3 7 3 DIAGnostic ROSCillator EFControl ABSolute CSAC This query returns the Electronic Frequency Control EFC steering value of the MAC Rubidium oscillator in parts per trillion 1E 012 3 7 4 DIAGnostic ROSCillator EFControl ABSolute FILTer This query returns the Electronic Frequency Control EFC steering value of the filter oscillator in Volts 3 7 5 DIAGnostic LlFetime COUNt This query returns the time since power on of the MAC Rubidium oscillator in hours 3 7 6 DIAGnostic Sending the command diag returns the following Relative oscillator setting Absolute oscillator setting Time since power on in hours lifetime An example of the syntax scpi gt diag EFControl Relative 0 025000 EFControl Absolute 5 Lifetime 871 3 8 MEASURE Subsystem The MEASURE subsyste
91. rious internal connectors such as the RS 422 interfaces the LCD connector 5MHz output and an additional 10MHz buffered output The unit may be operated with the lid opened removed or the lid may be modified to allow additional connections such as low profile bulkhead DB 9 connectors to provide external accessibility to these connections 2 7 Major Connections The major connections and features of the LN Rb GNSDO PCB are shown in Figure 2 3 Figure 2 3 Major connections and features of the LN Rb GNSDO PCB ba bts t SS GNSS USB Option f gt SO UNIPIQNY SJNJEIUIN IA AS abBeyor op ndul re LCD Page QUAN 1 UI Feli E Om AUTO SURVEY bml 10MHz Low Noise aa Festa ER mA Power Control J1 KiF des a Pale a 009 VE fi Table 2 1 shows the functions supported on connector J1 This connector is compatible to the legacy JLT CSAC GNSDO connector J1 except pin 13 which is now a secondary CMOS SV 1PPS output 2015 Jackson Labs Technologies Inc Low Noise Rubidium GNSDO tm User Manual 2 7 1 Power Harness Pinning 10 Table 2 1 Connector J1 pinout Jackson e Ref Name Function Specification J1 1 ISP Enter ISP mode GND pin 1 to activate J1 2 RST_IN Reset the instrument GND pin 2 to activate J1 5 LCD_KEY Cycle through the LCD GND momentarily to cycle pages Initiate LCD pages GND for more Auto Survey Wired in than 8 seconds to initiate an para
92. rol data for the selected servo loop Values from 2 0 to 50 are typically used Larger values result in less noise at the expense of phase delay and may cause loop instability This command has the following format SERVo EFCDamping lt int gt 2 4000 3 10 10 SERVo TEMPCOmpensation This parameter is a coefficient that reflects the correlation between the temperature of the Rubidium or filter oscillator versus the required frequency steering Monitoring the tempco and aging parameters provides a mechanism to track the health of the Rubidium or filter oscillator Excessively high values that appear from one day to the next could be an indicator of failure on the board This coefficient is automatically computed and adjusted over time by the Jackson Labs Technologies Inc firmware This command has the following format SERVo TEMPCOmpensation lt float gt 4000 0 4000 0 3 10 11 SERVo AGINGcompensation This parameter is a coefficient that represents the drift of the EFC needed to compensate the natural drift in frequency of the Rubidium or filter oscillator due to aging This coefficient is automatically computed and adjusted over time by the Jackson Labs Technologies Inc firmware This command has the following format SERVo AGINGcompensation lt float gt 10 0 10 0 3 10 12 SERVo PHASECOrrection This parameter sets the Integral part of the PID loop for the selected servo loop and therefore the time constant of the phase error c
93. s Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs 3 4 1 GYRO MODE lt ON OFF gt Enables or disables electronic compensation This feature must be calibrated at the factory before it can be used 3 4 2 GYRO TRACE lt int gt 0 255 This command sets up the output period of the Accelerometer data in g s per axis and in tilt in Degrees per axis The fastest period is 50ms 20 outputs per second achieved when setting the command to GYRO TRACE 1 The resolution of this command is 1 20 of a second Setting the command to 0 disables the Accelerometer output This command has the following format GYRO TRACE lt int gt 0 255 GYRO TRACE returns the setting of the period of this command The output of the system is in six floating point numbers the acceleration on the X Y and Z axis in g s and the Tilt of the X Y and Z axis in Degrees 90 to 90 Please note that the Accelerometer has its best resolution and accuracy when the earth s gravitational acceleration is perpendicular to the axis to be measured Thus the sensors accuracy and resolution will be best when the tilt of any axis is around 0 Degrees The worst performance with an accuracy of only 5 Degrees is when any of the axis are at their 90 Degree angles this is due to the fact that a SIN g load calculation is done to generate the output normalized to Degrees and the vector is thus least sensitive at 90 Degree angles
94. s the filter oscillator to the MAC Rubidium oscillator The third party applications GPSCon or Z38xx can be used to graph and monitor either servo loops performance by selecting the desired loop with this command Please note that for proper operation of the LN CSAC variant of the product this setting needs to be kept at the factory default setting of SERV SEL CSAC because that version of the product does not include an external filter oscillator the phase noise filter oscillator is located inside the Microsemi LN CSAC oscillator for this version of the product 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs 3 10 2 SERVo MODE lt SLOW MEDium FAST AUTO gt This command allows auto setting of all of the servo loop parameters to factory default values as described in section 2 8 with one single command entry This command is useful in setting the filter loop time constants for differnet mission profiles to accomodate different usage scenarios of the product The loop time constant of the PLL loop phase locking the crystal filter oscillator OCXO to the MAC Rubidium can be chosen with these settings The AUTO mode lets the firmware determine by itself which loop time constant is used thus optimizing the units performance dynamically depending on the environmental effects on the OCXO The AUTO setting will quickly react to phase pertrubations and will try to seta SLOW setting long time
95. s warmup time to atomic lock in the same enclosure as the Rubidium version Please note that throughout this document as well as on the LCD display and serial interface we refer to the Chip Scale Atomic Clock CSAC This is to be interpreted as being synonymous with the Rubidium MAC for the purposes of backwards compatibility with the CSAC GNSDO and related software Similarly this unit offers multi satellite system reception and the terms GPS GNSDO GNSS and GPSDO can also be used interchangeably for purposes of this discussion The heart of the LN Rb GNSDO is a Rubidium Vapor Cell oscillator manufactured by Microsemi The internal Microsemi Miniature Atomic Clock MAC breakthrough VCEL laser technology and small Rubidium vapor cavity allow the Atomic Reference Oscillator to be packaged in a unit significantly smaller and with significantly less power consumption than legacy products The MAC is binned into three different performance versions and paired with appropriate performance level ovenized Crystal oscillators OCXOs The highest performance version operates with a Phase Noise performance rivaling that of the lowest noise reference oscillators on the market 115dBc Hz at 1Hz offset and a noise floor of less than 168dBc Hz is a typical performance for example and combines this ultimate Phase Noise performance with extremely good ADEV performance less than 6E 013 ADEV from 0 1s to 5s and better than 8E 014 ADEV at 100Ks is typical on the U
96. s wider signal bandwidth and a different carrier frequency so requires Glonass compatible splitters and antennae It is also recommended that SBAS is enabled whenever GPS or QZSS is selected Please note that Glonass reception is disabled by default when the unit is shipped from the factory GNSS systems are enabled via the GPS SYST SEL serial command with GPS SBAS and QZSS enabled by default See also section 3 3 27 The GNSS receiver generates a 1PPS time signal that is phase synchronized to UTC GPS or UTC Glonass BeiDou QZSS This 1PPS signal is used to frequency lock the 1OMHz Sine Wave output of the LN Rb GNSDO to UTC thus disciplining the unit s Atomic Clock 10MHz frequency output to the relevant UTC reference clock for very high frequency accuracy typically better than 11 2015 Jackson Labs Technologies Inc 15 Low Noise Rubidium GNSDO tm User Manual J a ck S on Labs digits of frequency accuracy when locked to GPS or Glonass Using a high performance Timing GNSS receiver allows operation with a phase stability error of typically less than 10 nanoseconds steady state anywhere in the world 2 7 7 Connecting an LCD Display 16 An optional industry standard alphanumeric LCD display may be connected to the units internal LCD connector for displaying status information LCD s with 16x2 characters are optimal but 20x2 or 20x4 displays may also work An example low cost display is available from www mouser com N
97. se Rubidium GNSDO User Manual J a ck S on Labs Figure 4 1 Location of header J2 internally to the enclosure FONOL HI AS abeyoA Op yndu J0 2 SQ unipiqny anelu ug ys Wy 4 AUOJUJIUULU S A IJ gt Le o o w N 4 N sA out pins 1 and 2 of J2 prior to power on to di enter ISP mode of J1 prior to power on to enter ISP mode 4 4 Downloading the Firmware Download the latest version of Low Noise Rubidium GNSDO firmware from the Jackson Labs Technologies Inc support website and store it in a place that will be remembered The file is in hex format The unit needs to be connected to the computer s RS 232 serial port prior to firmware download Connect a DB 9 serial connector to the Low Noise Rubidium GNSDO as indicated in Section 2 6 Please note that the unit can only be upgraded through the RS 232 port not through the USB serial port 4 4 1 Using the Flash Magic Flash Programming Utility A Open the Flash Magic utility Set the COM port in the Flash Magic application as needed on your PC Set Interface to None ISP 68 2015 Jackson Labs Technologies Inc J a C Kk S O n Low Noise Rubidium GNSDO User Manual Labs Figure 4 2 Flash Magic Programming Utility lee IQSa va gt e F108 Select Device LPC2138 Erase block O 0x000000 0x000FFF Erase block 1 0x001000 0x001FFF COM Port COM 4 Y Erase block 2 0x002000 0x002FFF gt Erase block 3 0x003000 0x003FFF
98. sired stop point This can all be unlocked by left double clicking anywhere on the graph Double click always causes all of the selected span data to be displayed At the next update cycle the selected span if not set to zero will be enforced However the left click and if chosen the right click always overrides the span setting To display all of the data in the file without manually setting the span to zero you should right double click in the graph This has the effect of setting the start time to zero the stop time to infinity and asserting the mouse override condition To release left double click Since this is harder to describe than to actually do here is a paraphrase of the above 2015 Jackson Labs Technologies Inc 77 Low Noise Rubidium GNSDO User Manual J a ck S on Labs To zoom in The mouse is used to set the left extent and the right extent of the portion of the curve that the user wants to fill the screen Click once with the left mouse button on the point that marks the left side of what you want to be the magnified curve Immediately that point becomes the left end of the curve Then similarly click the right mouse button on the curve at the time you wish to be the right most portion of the magnified curve and it immediately becomes the end point on the right side And finally to return to the zoomed out fit to window view left double click on the curve Remember in order to see all the data in the log file
99. t can be significant 35m or more are common 3 3 7 GPS GGASTat This command instructs the Low Noise Rubidium GNSDO to send a modified version of the NMEA standard string GPGGA every N seconds with N in the interval 0 255 The command is disabled during the initial warm up phase This command has the following format GPS GGASTat lt int gt 0 255 This command replaces the regular NMEA GGA validity flag with a decimal number indicating the lock state of the unit Please see section 3 10 15 for a detailed description of the lock state variable The command allows capture of the position and other information available in the GGA command as well as tracking the lock state and health of the unit s oscillator performance GGASTat shows height in MSL Meters this is different from traditional GPS receivers that display height in GPS Meters The difference between MSL and GPS height can be significant 35m or more are common 3 3 8 GPS GPRMC This command instructs the Low Noise Rubidium GNSDO to send the NMEA standard string GPRMC every N seconds with N in the interval 0 255 The command is disabled during the initial warm up phase This command has the following format GPS GPRMC lt int gt 0 255 36 2015 Jackson Labs Technologies Inc Jackson m 3 3 9 GPS GPZDA Low Noise Rubidium GNSDO User Manual This command instructs the Low Noise Rubidium GNSDO to send the NMEA standard string GPZDA every N seconds with
100. t of the commands available for the Low Noise Rubidium GNSDO 3 3 GPS Subsystem Note Please note that Low Noise Rubidium GNSDO displays antenna height in MSL Meters rather than in GPS Meters on all commands that return antenna height the legacy Fury GPSDO uses GPS height The NMEA position fixes are in the WGS84 coordinate system while the X Y and Z velocity vectors are given in the ECEF coordinate system The GPS subsystem regroups all the commands related to the control and status of the GNSS receiver The list of the commands supported is the following GPS SATellite TRAcking COUNt GPS SATellite VISible COUNt GPS PORT lt RS232 USB gt GPS PORT GPS GPGGA lt int gt 0 255 GPS GGASTat lt int gt 0 255 GPS GPRMC lt int gt 0 255 GPS GPZDA lt int gt 0 255 GPS GPGSV lt int gt 0 255 GPS PASHR lt int gt 0 255 GPS XYZSPeed GPS DYNAMic MODE lt int gt 0 7 GPS DYNAMic MODE 8 Automatic Dynamic Mode GPS DYNAMic MODE GPS DYNAMic STATe GPS REFerence ADELay lt float gt lt s ns gt 32767ns 32767ns GPS REFerence PULse SAWtooth GPS RESET ONCE GPS TMODE lt ON OFF RSTSURV gt GPS SURVey ONCE GPS SURVey DURation lt sec gt 34 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs GPS SURVey VARiance lt mm 2 gt GPS HOLD POSition lt cm cm cm gt GPS SURVey STATus GPS INITial DATE lt yyyy mm dd gt GPS INITial TIME lt hour min sec gt GPS SY
101. t the length of the string is fixed at 115 characters plus the two binary 0x0d Ox0a termination characters 2015 Jackson Labs Technologies Inc 37 Low Noise Rubidium GNSDO User Manual J a ck S on Labs PASHR POS 0 aa bbbbbb 00 cccc ccccc d eeeee eeeee f ggsss ss hhhh iii ii jjj jj kkkk kk IL1 mm m nn n 00 0 p pp checksum Where aa Number of Sats bbbbbb 00 Time of Day UTC cccc ccccc d Latitude S N eeee eeeee f Longitude W E ggggg gg Antenna Height in meters hhhh Four fixed symbols kkkk k Vertical Velocity in meters s 111 PDOP mm m HDOP nn n VDOP 00 0 Static number p pp Firmware version This command instructs the Low Noise Rubidium GNSDO to send the NMEA standard string PASHR every N seconds with N in the interval 0 255 The command is disabled during the initial warm up phase This command has the following format GPS PASHR lt int gt 0 255 3 3 12 GPS XYZSPeed 38 This command is a 3D velocity vector output command Enabling this command will output a 3 dimensional velocity vector indicating the unit s speed in centimeters per second in the ECEF coordinate system X Y and Z speed are individually given and are independent of each other An accuracy estimate in centimeters per second is also given The velocity data is time stamped using the time of week with a resolution of milliseconds Additionally the number of accrued Leapseconds is indicated in this message which allows pr
102. t the unit does not generate a 1PPS pulse until the GNSS receiver has locked onto the Satellites With the command SYNC OUT 1PPS RESET ON the unit can now be configured to generate an asynchronous 1PPS output after power on even if a GNSS antenna is not connected to the unit Once the GNSS receiver locks the 1PPS pulse will align itself to UTC by stepping in 10 equally spaced steps toward UTC alignment The default setting is OFF which means the 1PPS pulse is disabled until proper GPS lock is achieved This command requires a power cycle or system reset to be activated 3 6 13 SYNChronization OUTput 1PPs RESET This query returns the 1PPS output on reset setting 3 6 14 SYNChronization OUTput 1PPS DOMAIN lt CSAC FILTer gt This command selects between the Rubidium and filter oscillator 1PPS outputs on the 1PPS SMA connector The CSAC option selects the Rubidium oscillator 1PPS while the FILTer option selects the filter oscillator 1PPS The phase of these two selections may vary by more than 100ns during warmup and this phase difference can be queried by commands described in section 3 6 6 3 6 15 SYNChronization OUTput 1PPS DOMAIN This query returns the 1PPS output domain setting 3 6 16 SYNChronization OUTput FiLTer lt ON OFF gt This command enables disables the Phase Noise filter on the buffered 10MHZ frequency output connectors If selected ON the output of the filter oscillator is routed to the buffered outputs If de s
103. tput does come at a slight ADEV performance penalty at averaging intervals of less than several 100 seconds so enabling or disabling the TCXO filter on the standard performance option depends on the application requirements Phase Noise or ADEV priority Figure 2 21 TCXO Phase Noise filter versus MAC only output Phase Noise f in dBc Hz PM Spur Offset 1 110 0 120 0 130 0 140 0 150 0 160 0 1Hz 10Hz 100 Hz kHz race Notes input Freq input Amplitude RefFreg Ref Amplitude Sample interval dBcHzat70kHz T Duration Acquired instrument 10 kHz 100 kHz LN Rb 0 31 fiter dacg 50 efcs 2 phaseco 40 LN Rb vs Fury Unsaved 10 000MHz 10 3 dBm 10 000 MHz 125d8m 0 1005 154 9 16h25m2s 591023pts TimePod 5330A LN Rb 0 31 filter dacg 50 efcs 2 phaseco 40 LN Rb vs Fury Unsaved 10 000MHz 10 4 dBm 10 000MHz 12 5 dBm 0 1005 146 9 3h 35m 55s 129551pts TimePod 5330A 2015 Jackson Labs Technologies Inc 29 Low Noise Rubidium GNSDO tm User Manual J a ck S O n Labs Figure 2 22 shows the typical phase noise performance of the unit when ordered with the low power low noise Cesium Atomic Clock CSAC oscillator option Figure 2 22 Typical Phase Noise performance of Low Power Low Noise CSAC Phase Noise f in dBc Hz 109 PM Spur Offset Hz dec 01 657 600 4346 1200 1165
104. y of this utility Only a few of the features and commands are mentioned in this chapter for convenience 5 4 1 Setting the options To set up the options for your GPSCon session press the Options button below the display area The window shown in Figure 5 1 will appear You can select from the tabs which options you wish to set Figure 5 1 Options window GPSCon Utility Pro GPSCon COMA O A A mie Status Time Map Graph Export Help About Tem II Paths amp settings FTP Email Coms Time services Auxiliary Aux coms Export graphics Remote control Logging and graph M Log Status yne documents jackson_labs gpscon gpsiog loc M Log EFC Max kB 0 unlimited jo t MN Log sat count M Tito GPS m Local HTML and image files HTML file c program fies 86 gpscon gpsstat htm Browse M Log PU Bit from display bitmap M Translate time codes Piels 317 HTMLupdate interval 30 21 secs Continuously read error queue Flash LED Satellite tracking history file FF Use bamap Track file c program files amp 86 gpscon gpsdmp bin Browse AA Max kB 0 unlimited 512 M Show best fit to EFC mm 3 EN FT ANSI font in status PF Timax g ns Filter coeff 0 025 5 4 1 1 Communication Parameters Before you can use GPSCon you must set the communication parameters for your system Open the dialog box by pressing the Options button Then s
105. z to 10 F Check the box marked Erase blocks used by Hex File Warning Make sure NOT to check the box marked Erase all Flash Code Rd Prot under any circumstances this may erase factory calibration data and the unit will not operate and will have to be returned to the factory Checking this box on the ISP utility will thus void the warranty G Under Step 3 Hex File browse for the hex file that you downloaded in step 4 4 H Go to Step 5 and press Start You will observe the firmware being downloaded to the Low Noise Rubidium GNSDO 4 5 Verifying Firmware Update 72 Power cycle the unit Both LED s should blink During power on the unit sends an ID string out of the serial port at 115200 Baud by default The firmware version can also be queried by sending the IDN command Verify that the firmware version is the version that was downloaded O 2015 Jackson Labs Technologies Inc J a C k S O n Low Noise Rubidium GNSDO User Manual Labs GPSCon Utility 5 1 Description GPSCon is a program useful in the monitoring and controlling a variety of GPS time and frequency standard receivers It communicates with the receiver using the SCPI command set GPSCon can be used to monitor either the Rubidium oscillator or filter oscillator servo loops by selecting the desired servo loop with the SERVo SELect command see also section 3 10 1 This utility can be obtained directly from Real Ham Radio c

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