Navman 20 GPS Receiver User Manual
Contents
1. INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE CONSEQUENTIAL OR INCIDENTAL DAMAGES MERCHANTABILITY OR INFRINGEMENT OF ANY PATENT COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT NAVMAN FURTHER DOES NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION TEXT GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS NAVMAN SHALL NOT BE LIABLE FOR ANY SPECIAL INDIRECT INCIDENTAL OR CONSEQUENTIAL DAMAGES INCLUDING WITHOUT LIMITATION LOST REVENUES OR LOST PROFITS WHICH MAY RESULT FROM THE USE OF THESE MATERIALS Navman products are not intended for use in medical lifesaving or life sustaining applications Navman customers using or selling Navman products for use in such applications do so at their own risk and agree to fully indemnify Navman for any damages resulting from such improper use or sale Product names or services listed in this publication are for identification purposes only and may be trademarks of third parties Third party brands and names are the property of their respective owners Additional information posted at www navman com is incorporated by reference Reader response Navman strives to produce quality documentation and welcomes your feedback Please send comments and suggestions to tech pubs navman com For technical questions contact your local Navman sales office or field applications engineer LA000577C 2006 Navman New Zealand All rights reserved Proprietary information2. Table 3 2 Low power acquisition input values This message is the NMEA equivalent of the SiRF Binary input message ID 167 System response PTTK LPACQ aaaaaa bbbbbb cccc d CS The updated values returned by the system are as described in Table 3 2 3 5 Control of GPIO connections via serial commands Jupiter 20 Note The information in this section does not apply to the Jupiter 30 module The Jupiter 20 receiver has many unused GPIO user programmable input output signal pads These can be utilised in the application by introducing custom software written with the SiRF SDK Software Development Kit tools Alternatively the receiver has an NMEA default instruction protocol that can control these IO ports through the standard serial communication ports using proprietary NMEA commands The GPIO lines are treated as a single 8 bit register with the pins occupying the positions shown in Table 3 3 LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 20 E GP1015 Fwd Rev GPIO1 Wheel Tick GPIO3 Gyro In GPIO5 SDI GPIO6 SDO GPIO7 SCLK GPIO9 1PPS MSB 7 GPIO10 GPS Fix Table 3 3 Pin configuration of the GPIO lines On the Jupiter 20 D there is no control of GPIO15 GPIO1 GPIO3 GPIO5 GPIO6 or GPIO7 and all references to these pins are ignored In each of the messages described in the following sections x represent
3. and specifications subject to change without notice 23
4. antenna supply into the NANT_SC input When a short circuit occurs this line will go low This design provides the lowest cost solution for this function Other designs can be created giving higher stability over a wide temperature range using operational amplifiers Discrete antenna current monitor Q1 L1 120R 100 MHz SUPPLY_IN _ gt _ gt VANT gt NANT_SC _ ANT_CTRL _ gt ANT_OC Figure 2 11 Antenna short open circuit sensor circuit 3 3V supply only LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 15 2 7 Jupiter adapter printed circuit board The module supplied in the Development kit is mounted on a carrier PCB in a method typical of a customer application This carrier PCB illustrates and implements many of the design considerations discussed in this document The module is interfaced through two separate 20 pin data connectors with different header pitches This is for development purposes and provides a simple way to evaluate the surface mount module The RTC Real Time Clock backup supply voltage can be provided by an onboard lithium cell or from the development unit backup supply The adapter board carries the antenna DC supply over current protection circuits as shown in Figure 2 11 and a switch de bounce IC to provide reliable reset action from the development unit Figure 2 12 shows the adapter board w
5. calculates the magnetic variation the Jupiter 30 does not Magnetic Variation fields in G6PRMC The last two fields in the message GPRMC are the magnetic variation An Easterly variation should be subtracted from or a Westerly variation added to the true heading to give the magnetic heading the heading given by a magnetic compass For example the output might be GPRMC 220137 250 A 4331 9077 S 17238 2308 E 0 075949 168 82 071004 23 1 E 4C Standard SiRF output GPRMC 220137 250 A 4331 9077 S 17238 2308 E 0 075949 168 82 071004 17 Magnetic Heading field in GPVTG The third field in the message GPVTG is the magnetic heading denoted by the M in the following field This is the heading that would be reported by a magnetic compass For example the output might be GPVTG 168 82 T 145 70 M 0 08 N 0 14 K 41 The standard SiRF output GPVTG 168 82 T M 0 08 N 0 14 K 58 3 3 3 Altitude output The module outputs the correct altitude and geoid separation in the 6PGGA NMEA message Most SiRFstar based modules output the height above the current datum usually WGS84 ellipsoid as the altitude contrary to the NMEA specification and older modules omit the geoid separation The Jupiter receiver outputs the height above mean sea level as required by the NMEA specification For example the output might be GPGGA 220137 869 4331 9077 S 17238 2308 E 1 06 1 6 61 7 M 11 3 M 0 0 0000 55 Standard SiRF output v2 3 and earlier
6. data corruption Refer to Table 2 3 for suggested values of decoupling relative to the function desired J1 coaxial connector MCX SMA or MMCX ABAT o ied ce GND V i Digital AGND serial data ports to application processor 3V RTC lithium or RS232 level converter backup battery GPIO GPS_FIX GPIO NANT_SC GPIO RXB GPIO TXB GPIO WAKE_UP LA gt SDO 27_ GPIO ANT_OC a m spi Figure 2 2 Sample application circuit Function Decoupling PWRIN 1 unt BOOT 27pF RXA 27pF TXA 27pF TXB 27pF RXB 27pF NANT_SC 27pF RF_ON 27pF ACTIVE_PWR 1nF VCC_RF 1nF V_BATT 1 unt NRESET 27pF GPS FEIS GPIO13 GPIO4 WAKEUP ANT_OC ANT_CTRL 1PPS Note represents a parallel connection OLOINI OD a R wo Table 2 3 Decoupling recommendations LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 8 2 4 4 Serial RS232 data level shifter To connect the module to a PC comm port the serial data signals must be level shifted to RS232 levels This has not been shown in the reference design but many single chip RS232 level shifters are available such as MAX3232 Note It is highly recommended to provide test points on the serial data lines and Boot signal pad 3 even if the application circuit does not use these signals This will allow the user to connect to thes
7. flow through the module antenna power feed components The circuit shown in Figure 2 9 will provide over current protection 70 mA Antenna supply current limit x OH L3 ToO SUPPLY_INPUT n BCSSIE 120R 100 MHz ANTENNA_SUPPLY 3 svpc lt _ lt vant 100nF SS c7 100nF 18pF GND Rib GND GND Figure 2 9 Simple current limiter circuit Transistor Q1 serves as a series pass transistor Q2 is used to sense the current in the antenna circuit turning off Q1 if the voltage across the current sense resistor R1 exceeds 0 6V This circuit does not turn off the supply to the antenna but merely limits it to a safe value With the components shown the supply will be limited to approximately 70 mA Other options are available to provide this function MAXIM can supply a current trip IC that will turn off the load if a preset supply current is exceeded The part number for this is MAX4785 The circuit is shown in Figure 2 10 Antenna current limit using an IC antenna short circuit sense signal antenna power enable Njo A joo lt _ PWR_IN Jupiter GPS Module Figure 2 10 Active current limit using an IC Electro resistive fuses can be used to protect the supply over current These are available from Bourns Vitromon and other manufacturers LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 14 Antenna short open sense inputs and cont
8. paste is used to prevent the need for post reflow washing If a washing process is used an aqueous wash is not recommended due to the long drying time required and danger of contaminating the fine pitch internal components 2 3 7 Pre baking The modules are delivered on a tape and reel package sealed in an airtight bag The MSR Moisture Sensitivity Rating is 3 therefore they should be loaded and reflowed within 168 hours If the modules are in ambient humidity for longer than this a pre baking drying process will be required 2 3 8 Rework Navman recommends that rework and repair is carried out in accordance with the following guidelines e IPC 7711 Rework of Electronic Assemblies e IPC 7721 Repair and Modification of Printed Boards and Electronic Assemblies Note Jupiter 30 and Jupiter 20 modules are covered by a 12 month warranty 2 4 Typical application circuit The schematic in Figure 2 2 represents a very basic application circuit with simple interfaces to the module It is subject to variations depending on application requirements Note Refer to the Jupiter 20 Dead Reckoning Application Note LA000433 for the Jupiter 20D reference design 2 4 1 Power for receiver and active antenna The receiver power connection requires a clean 3 3 VDC Noise on this line may affect the performance of the GPS receiver When an active antenna is used the DC power is fed to it through the antenna coax This requires the user to ap
9. 5 Control of GPIO connections via serial commands Jupiter 201 20 3 5 1 Configure port te EE 21 3 5 2 Set OUtPUtS i ees uereg Eege AALE 21 3 5 3 Clear lire EE 21 3 5 4 REA Mile TC 21 3 6 GPS Ee TEE 21 3 7 Antenna power monitor messages eee eete eee ee taaeeeeeetneeeeeeetaeeeeereaea 22 3 8 Custom application software 22 4 0 Glossary and aCronymMsS essEaEEERVOEEEEEENEEEeeEeESEEEEEESREEEEENESeEENeEEEEREEENEEEdEEeNEG 23 LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice Figures Figure 2 1 Lead free and tin lead reflow profile recommendation Figure 2 2 Sample application circuit Figure 2 3 Recommended application layout dimensions Figure 2 4 Typical module layout Figure 2 5 Example PCB layout for external active antenna Figure 2 6 PCB microstrip dimensions Figure 2 7 Arrangement of active antenna and application board Figure 2 8 Cross section of application board with passive patch amtenng Figure 2 9 Simple current limiter circuit Figure 2 10 Active current limit using an IC Figure 2 11 Antenna short open circuit sensor circuit 3 3V supply on Tables Table 2 1 Jupiter 30 and Jupiter 20 Module pin functions Table 2 2 Summary of pin multi functionality Table 2 3 Decoupling recommendations Table 2 4 PCB substrate thicknesses v track width Table 2 5 Passive and active antenna features Table 2 6 Recommended a
10. GPGGA 220137 869 4331 9077 S 17238 2308 E 1 06 1 6 72 0 M M 0 0 0000 6D Or v2 3 1 and 2 3 2 GPGGA 220137 869 4331 9077 S 17238 2308 E 1 06 1 6 72 0 M 11 3 M 0 0 0000 50 LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 19 3 4 Navman proprietary NMEA low power mode messages Navman has added a number of proprietary NMEA input messages to configure the TricklePower and Push To Fix modes 3 4 1 Low power configuration The following message sets the receiver to low power mode PSRF151 a bbbb cccc CS lt CR gt lt LF gt where Field Description a Push To Fix 1 on 0 off b TricklePower duty cycle parts per thousand c TricklePower on time milliseconds Note that Push To Fix does not require fields b and c so they may be left blank Table 3 1 Low power modes message values This message is the NMEA equivalent of the SiRF Binary input message ID 151 System response PTTK LPSET a bbbb cccc CS The updated values returned by the system are as described in Table 3 1 3 4 2 Low power acquisition configuration The following message sets the acquisition parameters of the low power mode PSRF16 7 aaaaaa bbbbbb cccc d CS lt CR gt lt LF gt where maximum off time milliseconds maximum search time milliseconds c Push To Fix period seconds d adaptive TricklePower 1 on 0 off
11. U processing capacities and UO capabilities The custom application software can be invoked internally or externally providing the ability to dedicate the module as the host application or an external processor as the host The module also provides the ability to communicate externally with standard or customer specific communication protocols The custom application software has access to the flash memory navigation data from the GPS Navigation software and access to various I O lines used on the module This can be developed using the SIRF SDK The SDK provides all the tools and resources necessary for custom software development Refer to http www sirf com for more information about the SDK LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 22 4 0 Glossary and acronyms EMI Electromagnetic Interference FR4 substrate Flame Retardant type 4 The usual base material from which plated through hole and multi layer printed circuit boards are constructed The type 4 indicates woven glass reinforced epoxy resin GPS Global Positioning System A space based radio positioning system that provides accurate position velocity and time data NMEA National Marine Electronics Association RF Radio Frequency SRAM Static Random Access Memory TTFF Time To First Fix The actual time required by a GPS receiver to achieve a position solution This spe
12. ad interface Details of the module connector configuration are shown in Table 2 1 LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 4 main power input 3 3V ground serial boot high for serial boot low or open circuit for normal operation CMOS level asynchronous input for UART A CMOS level asynchronous output for UART A CMOS level asynchronous output for UART B CMOS level asynchronous input for UART B output to indicate whether the RF section is enabled active high ground ground GND ground GND ground GND ground GND ground GND ground RF_IN RF input GND ground active power input 70mA current limit supply to this pin VCC_RF O RF Power 2 85V supply output V_BATT backup battery input external reset active low voltage on PIN 22 NRESET must not exceed PWRIN at all times GPS_FIX GPS fix indication active low ACTIVE_PWR NRESET pins 24 28 multi functional see table 2 2 1 pulse per second output ground Table 2 1 Jupiter 30 and Jupiter 20 Module pin functions LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice Jupiter 30 Jupiter 20 Pin GPIO Name and Description GPIO Standardig DR fu
13. ater than 2 hours the unit will revert to a warm or cold start This is caused by the stored ephemeris data becoming invalid after 4 hours 3 2 Power management The TricklePower mode of operation can be enabled to reduce the average power consumption The main power is supplied to the module continuously An internal timer wakes the processor from sleep mode The module computes a navigation position fix after which the processor reverts to sleep mode The duty cycle is controlled by a user configurable parameter If ephemeris data becomes outdated the TricklePower mode will attempt to refresh the data set within every 30 minute period or for every new satellite that comes into view With TricklePower set to a 20 duty cycle a power saving of 50 can easily be achieved with minimal degradation in navigation performance LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 17 3 2 1 Adaptive TricklePower mode In Adaptive TricklePower mode the processor automatically returns to full power when signal levels are below the level at which they can be tracked in TricklePower mode This is the default behaviour when TricklePower is active Adaptive TricklePower is always enabled on the Jupiter 30 and Jupiter 20 S XTrac and selectable on the Jupiter 20 standard module 3 2 2 Push to Fix mode Unlike TricklePower the operation in this mode is not cyclic Th
14. bk NAVMAN Jupiter 30 20 GPS receiver module Integrator s Manual Related documents Jupiter Series Development kit guide LA000645 e Navman NMEA reference manual MN000315 e SIRF Binary Protocol reference manual SC EY Pe LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice Contents Ride e DT de EE 4 2 0 Hardware application information ccccesssssssseeeeeeeeeeeeessneeeeeeeeeeseesennaees 4 2 1 Electrical connections SMT pad Interface 4 2 2 Physical UE Ee TEE 6 2 3 Manufacturing process recommendations s esseeeseeeseteeiettit tiet ttrtttrntsrrnstrnnse nnet 6 2 3 1 Reflow recommendations cccccccceesececeeeeeeeeeeeceeeeeeaaeeceneeeesaaesseneeesicaeeneneees 6 2 3 2 Connection pad material netr tst ttr tnn nenna nesteen nEn Ennn nnen 6 2 3 3 Solder paste mask EE 7 2 3 4 Solder paste LY PO EE 7 KE el DEE 7 2 3 6 Post reflow WASHING sissi RE e EE a E E R 7 AS El e ME 7 2 93 98 e IEN 7 2 4 Typical application circuit ec eect terete eerie eee ee eieee eee tieeeeeeenieeeeertiaeeeeeenea 7 2 4 1 Power for receiver and active antenna ssesseseresrrsssrrsstrtstttsttnsstnnesnstsrnesrne 7 E Ee In Le e EE 7 2 43 DECODING BEE 8 2 4 4 Serial RS232 data level bitter 9 2 4 5 Externall RF LEE 9 2 5 PCB design recommendatlons strun ttrnntnnnsttnstnn nnne n tnt 9 2 5 1 Re
15. cification will vary with the operating state of the receiver the length of time since the last position fix the location of the last position fix and the specific receiver design 2006 Navman New Zealand All Rights Reserved SiRF and SiRF logo are registered trademarks of SiRF Technology Inc SiRFstar SiRFLoc Push to Fix and Trickle Power are trademarks of SiRF Technology Inc All other trademarks mentioned in this document are property of their respective owners Information in this document is provided in connection with Navman New Zealand Navman products These materials are provided by Navman as a service to its customers and may be used for informational purposes only Navman assumes no responsibility for errors or omissions in these materials Navman may make changes to specifications and product descriptions at any time without notice Navman makes no commitment to update the information and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to its specifications and product descriptions No license express or implied by estoppel or otherwise to any intellectual property rights is granted by this document Except as provided in Navman s Terms and Conditions of Sale for such products Navman assumes no liability whatsoever THESE MATERIALS ARE PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND EITHER EXPRESSED OR IMPLIED RELATING TO SALE AND OR USE OF NAVMAN PRODUCTS
16. commended PCB pad layout ticissaatciaisassnssciarnsssintiaiacatidueranandeunuatascuninaaibdadnaeaae 9 2 5 2 General recomMendations rnet ttttrnsttnntr nsten tttnnttnnnstnnnnnnn nnna 9 2 6 Antenna system design choices nunne nnn nante en nant 12 2 6 1 Anena types See naa EEEE A EES 12 2 6 2 Active antenna ce eect eee eee cette eeeeeee eee teeeeeeeteeaeeeeeeceeeaaeeeeseneaeeeeseeeaeeeesenaneees 12 2 6 3 WEE EE 13 2 6 4 Jupiter module used as a GPS sensor 13 2 6 5 DC supply protection for an active antenna ccccccceeceeeeeeeeeeeeeeeeeeeeseeeeeneees 14 2 7 Jupiter adapter printed Circuit board nsan tnnn rennen 16 3 0 Software application information cccccesssesseeeeeeeeeeeeeeeeeeeeeeeeeeeseeseene 17 3 1 Normal mode operation sssneeseeseeseeeesttirtetstttttttt ttrt ttn nnt anaE EEE EErEE Ennen arrn EEEE Enn nn nnen 17 3 2 eg management EE 17 3 2 1 Adaptive TricklePower mode nn nnsttntttnnnnn nnen nennt 18 3 22 Push to FIx ele ET 18 3 3 Serial EE 18 3 3 1 Default Settings eee ee esene seneese ttssttssstnsstrnstnnntnnntnnnennnnnnnnnnnnnneen nnet 18 3 3 2 NMEA input commands Seet uNEENEEE EES EEE 18 3 3 3 Altitude OUT EE 19 3 4 Navman proprietary NMEA low power mode messages eeeeceeeeeeeeeeeeeeetteeteeeeeaes 20 3 4 1 Low power Copfiguration eee eeeeeeeeeeeeeeeeeeeteeeaaeeeeteeaeeeeeeeenaeeees 20 3 4 2 Low power acquisition Configuration c ccccceeeeceeeeeeceeeeeetecaeeeeeeeeteneeeeenees 20 3
17. e distance from signal track to nearest ground plane 2 If the antenna connection is routed under the module the track width should be approximately halved for that section only It is recommended that the antenna connection PCB track should be routed around the outside of the module outline kept on a single layer and have no bends greater than 45 degrees It is not recommended for production reasons to route the track under the module However if the track has to route under the module it should have a modified track width and solder mask to avoid short circuits to the underside of the module To minimise signal loss and reduce the requirement for vias it is not recommended to place the signal track on an inner layer of a multi layer PCB The PCB track connection to the RF antenna input must e have a characteristic impedance of 500hm e be as short as possible LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 11 e be interfaced to a coaxial connector if an external antenna is used e have maximum clearance to ground on the same layer or at least be half the substrate thickness e be routed away from noise sources such as switching power supplies digital signals oscillators and transmitters The PCB track connection to the RF antenna input must NOT have e vias e sharp bends components overlaying the track 2 6 Antenna system d
18. e output will be high This function can be overridden and the pin used as GPIO10 using the commands described in Section 3 5 The GPS fix output function returns after a reset LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 21 3 7 Antenna power monitor messages The Jupiter software includes antenna monitor messages driven by the state of the antenna monitor inputs The inputs NANT_SC short circuit detect active low and ANT_OC open circuit detect active high are configured as inputs and ANT_CTRL active antenna control is configured as an output If the function of any of these pins is overridden using the procedure described in Section 3 6 then this feature is disabled However if an antenna short circuit has occurred before any pins are overridden in this manner the status will continue to be reported as short circuit until such time as the active antenna control output is overridden In normal operation the active antenna control output is high If the short circuit detect pin goes low the active antenna control signal will go low This condition is latched until the user resets the module The active antenna control pin output is low when the receiver enters a low power mode due to TricklePower Push to Fix or APM and returns to its previous state when the receiver starts up again No checking of the antenna current is perfo
19. e signals if a firmware upload or new configuration is required These test points can take the form of an unfitted through hole connector Refer to Figure 2 2 showing test points TPO TPI amp TP 2 4 5 External RF filter If there is a high potential for interference EMI though the antenna system an external bandpass SAW filter may be added to the antenna input connection pad 17 which will attenuate interfering frequencies Many commercial active antennas have a filter so it would not be necessary to add another When using an active antenna the filter will not pass DC through to the antenna so an alternate power source would be required if an active antenna is used Alternatively a parallel RF choke across the filter will allow the antenna power to pass through but choice of components is important for example using a choke of sufficiently high self resonant frequency Care should also be taken not to exceed the filter maximum DC voltage 2 5 PCB design recommendations The modules are surface mounted devices hence the layout of the application PCB plays an integral part in the overall performance of the finished system It is not difficult to design such a PCB despite the presence of high frequency low level radio signals The following recommendations have been offered to allow the designer to create a design that will meet the requirements of this product 2 5 1 Recommended PCB pad layout The layout in Figure 2 3 sh
20. e variations as to how the antenna will receive its power but it is usually supplied through the coaxial cable via the antenna input as shown in Figure 2 7 Refer to Table 2 6 for the recommended active antenna characteristics Active GPS antenna connecting coax carrying GPS signals and DC power for amplification Application PCB Jupiter module coaxial connector fitted to application PCB Figure 2 7 Arrangement of active antenna and application board LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 12 2 6 3 Passive antenna A passive antenna does not require any power because it has no amplifier This is not the best choice if signal strength is a concern however it may be sufficient if the signal path is kept to a minimum usually below 300 mm An advantage to using a passive antenna is the ability to mount directly onto the application For best performance a passive patch antenna should have a metal ground plane about 80 mm in diameter placed directly under the antenna and it is advisable to screen the module and application circuits from the antenna For this reason the antenna and module should not be mounted on the same side of the PCB see Figure 2 8 passive patch antenna FR4 fibreglass PCB ground plane ground via Jupiter module 50 ohm microstrip Figure 2 8 Cross section of application b
21. esign choices 2 6 1 Antenna types There are two major types of GPS antenna passive and active The active antenna has a built in LNA Low Noise Amplifier to increase the strength of the signal and to compensate for the signal loss in a long cable connection The features of each type of antenna are shown in Table 2 5 comparing an externally mounted active antenna with a passive patch antenna mounted on the same PCB as the module Feature Passive antenna Active antenna requires short cable between antenna and receiver consumes power can be mounted remote from receiver gives good performance in poor signal situations has built in additional filtering low cost requires a coaxial connector Table 2 5 Passive and active antenna features 2 6 2 Active antenna An active antenna is a passive antenna with a built in LNA that requires a power supply Active antennas are used when the antenna input is connected to the receiver through a coaxial cable usually longer than 3m or any high loss transmission path The GPS signals experience loss in the transmission path from the antenna The loss is overcome by the antenna s LNA which amplifies the signal before it enters the transmission path The amplification is also used to enhance the signal in areas of low signal If the coaxial cable is shorter than 3m it may experience too much gain at the receiver and degrade the performance There are som
22. is mode always forces the GPS software to revert to a continuous sleep mode after a navigation position fix It will stay in sleep mode until woken by activation of the reset input Jupiter 20 or wakeup input Jupiter 30 and compute a fresh position If the ephemeris data becomes invalid or new satellites come into view the RTC has the ability to self activate and refresh the data thus keeping the restart TTFF very short This mode yields the lowest power consumption of the module and is ideal where a battery powered application requires very few position fixes For further information on the TricklePower and Push To Fix modes refer to the Low Power Operating Modes application note LA000513 3 3 Serial I O The module can output serial data in the NMEA format or SiRF Binary format The serial I O protocols are defined in the Navman NMEA reference manual MN000315 and the SiRF Binary Protocol reference manual These describe the format of the serial data from the module as well as the structure of the commands Navman has provided additional functionality to the NMEA protocol as detailed in the following sections 3 3 1 Default settings The default protocol is NMEA at a baud rate of 9600bps The frame format is 8 data bits no parity bit and 1 stop bit The following messages are output by default at a rate of once per second each GPGGA GPGLL GPGSA GPGSV GPRMC GPVTG GPZDA All output messages have checksums by defau
23. ith the positions of the connectors and indicators Aa a 2 l US 1 J2 not normally fitted PS fix LED GPS fix RTC backup battery not normally fitted power LED Jupiter module ANANA antenna Figure 2 12 Adapter printed circuit board LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 16 Refer to Table 2 8 for a description of the connector interfaces Jupiter J2 2 54 mm J1 2 mm pitch function pitch header header pin no pin no V_ANT VCC_RF V_BATT VDD M_RST GPIO GYRO IN GPIO FR BOOT GPIO W TICKS RFON GND TXA RXA GPIO SDI GND TXB RXB GPIO SCK GND GPIO SDO GND GND 1PPS GPS_FIX GPIO Note J2 Pin 16 on the adapter card is the wake up line for push to fix mode on the Jupiter 30 OLODINI ID A R w rm gt CH Table 2 8 Connector configuration 3 0 Software application information 3 1 Normal mode operation In normal mode of operation the baseband processor software runs continuously providing a navigation solution at the maximum rate of once per second No power saving functions are applied If the power to the module is disrupted the restart time can be shortened to a warm or hot start by keeping the RTC and SRAM contents valid with a backup battery on the VBATT input If the module has been turned off for gre
24. lt Note message GPZDA is not available for Jupiter 20S or Jupiter 20 D 3 3 2 NMEA input commands All NMEA input commands are in the form PSRFxxx CS lt CR gt lt LF gt where xxx is a decimal number between 100 and 255 inclusive Note In each case CS represents an NMEA checksum lt CR gt is carraige return lt LF gt is line feed These details are covered in the Navman NMEA reference manual MNO000315 Acknowledgements All input commands other than the standard SiRF commands will be acknowledged with a sentence of the form PTTK CS Where the arguments provided to a command are invalid the response will be the message PTTK NACK CS Checksums All input commands are accepted whether or not they include a checksum however if a checksum is included it must be correct in order for the message to be accepted Incorrect checksums will result in the response PTTK CHECKSUM CS LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 18 Unused messages Input messages where the message ID is not between 100 and 255 or where the message ID does not correspond to a specified function result in the response PTTK INVALID CS Errors Errors in message receipt other than checksum errors result in the response PTTK ERROR xx CS where xx is a hexadecimal error code Magnetic Variation Declination The Jupiter 20 module
25. nction XTrac name 24 13 reserved 6 GPIO SDO not connected 25 4 reserved 5 GPIO SDI ADC DOut WAKEUP A 8 push to fix wakeup active on ve edge i GPIO SCK ARSE FWD REV EE fwd rev input 27 15 antenna open circuit sensor input active 15 ANT_OC _ high low forward 9 high reverse 28 1 i ANT_CTRL 1 ANT_CTRL WHEEL_TICKS active antenna control output wheel tick input NANT_SC GYRO_IN 8 14 antenna short circuit sensor input active 3 NANT_SC gyro input low analogue 0 5 V Table 2 2 Summary of pin multi functionality GPIO Note that the Jupiter 20D Dead Reckoning does not support the active antenna supervisory functionality and associated proprietary NMEA status messaging see section 3 7 SPI Jupiter 20 only The Jupiter 20 GSW2 and Jupiter 20S XTrac do not support the SPI These pins function only as user GPIOs The SPI on the Jupiter 20D is used to control an internal ADC which interfaces to an external gyro Implementation of the SPI for any other alternative function requires an SDK Software Development Kit from SiRF 2 2 Physical dimensions The physical dimensions of the Jupiter 30 and Jupiter 20 modules are identical length 25 4mm 0 1mm width 25 4mm 0 1mm thickness 3 0 mm max weight 4 0g max 2 3 Manufacturing process recommendations 2 3 1 Reflow recommendations For lead based solder pastes the maximum reflow temperature is 225 C for 10 seconds For lead free solder pastes the maximum reflo
26. nd planes may not be required The ground return for any signal should have a clear path back to its source and should not mix with other ground return signal paths Hence the return path which is the ground underneath the microstrip antenna connection should not be shared with any digital signal or power supply return paths Pads 16 and 18 are the RF signal Ground connections Decoupling components The recommended values for power and signal decoupling are listed in Table 2 3 The placement of these components must ensure that the low value capacitors have very short tracks to the module pad and very close vias connecting them to the ground plane Figure 2 4 shows a typical layout Decoupling Capacitors FR4 Ground fibreglass Via plane PCB Jupiter module Figure 2 4 Typical module layout Antenna connection The PCB layout design of the antenna input connection requires appropriate selection of PCB track width substrate material and careful attention to the layout geometry If this overall system is not implemented correctly the module will receive poor GPS signals and therefore provide inferior navigation data Figure 2 5 illustrates an example of a PCB design integrating an external active antenna connected via an MCX or SMA coaxial connector Se Jupiter 30 20 outline Top Bottom Figure 2 5 Example PCB layout for external active antenna The modules can be used with a passive patch antenna if the co
27. nnection to the antenna input is very short It is possible to mount the patch antenna on the same PCB as the module but to reduce the possibility of digital noise it is recommended that the antenna be mounted on the opposite side of the board to the module LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 10 Design of 50 ohm microstrip antenna connection When designing the signal track from the antenna connection to the antenna input on the module a controlled impedance microstrip with a characteristic impedance of 50 ohms must be used The PCB parameters that affect impedance are as follows 1 Track width W 2 PCB substrate thickness H 3 PCB substrate permittivity 4 To a lesser extent PCB copper thickness T and proximity of same layer ground plane Figure 2 6 shows a representation of the PCB microstrip and its parameters WwW 4 H T Figure 2 6 PCB microstrip dimensions Table 2 4 shows typical track widths for an FR4 material PCB substrate permittivity of 4 3 at 1 5GHz and different PCB thickness The effect of track thickness T can be ignored for the short track lengths associated with this design Substrate thickness H mm Substrate Permittivity material E Table 2 4 PCB substrate thicknesses v track width Notes 1 If a multi layer PCB is used the thickness is th
28. ntenna characteristics Table 2 7 Antenna sense and control functions Table 2 8 Connector configuration Table 3 1 Low power modes message values sssseessssssrisssssrrssstrrrssstinrnnsttnrnnstrennnnt 20 Table 3 2 Low power acquisition input values ce eeeeeeeeeeeteeeeeeeetteeeeeetiteeeeeetteeeeere 20 Table 3 3 Pin configuration of the GPIO lines cccccescecceesteeeeeeessneeeeeesssneeeesssseeeeenees 21 Table 3 4 Antenna status output message values eee eeteeeeeeeeeeeeeeeeteteeeeeeetneeeeee 22 LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 1 0 Introduction The Navman Jupiter 30 and Jupiter 20 series of GPS receiver modules are complete GPS receivers designed for surface mount assembly SMT integration The modules provide a simple cost effective GPS solution for application designers Application integration will vary primarily with respect to antenna system design and EMI protective circuitry The Jupiter 30 is the successor to the established Jupiter 20 sharing the same form factor 25 4x25 4mm and electrical compatibility This provides a low risk migration path for existing users offering greater sensitivity lower power consumption and a faster fix Fundamental operation requires a 3 3 VDC power supply approximate current of 80 mA Jupiter 30 or 100mA Jupiter 20 GPS antenna system interface relevant EMI
29. oard with passive patch antenna Any cover close to the antenna called the superstrate will cause the resonant frequency and efficiency of the antenna to drop It is therefore recommended to keep any distance to the superstrate to a minimum of 3mm from the top surface of the patch See Table 2 6 for recommended characteristics of both passive patch and active antennas for use with the Jupiter receiver Characteristic Active antenna Passive antenna Polarisation right hand circular polarised right hand circular polarised 1 57542 GHz 1 57542 GHz 1 023 MHz gt 1 023 MHz Power supply 3V DC current lt 10mA at 3VDC 2 to 5dBi with 1dB loss max in connections Receive frequency Antenna gain Total gain includes antenna gain LNA gain and cable loss Axial ratio lt 3dB Output VSWR lt 2 5 lt 26dBi Jupiter 20 lt 18 dBi Jupiter 30 Table 2 6 Recommended antenna characteristics Note GPS active and passive antenna selection must include practical TTFF tests in weak and strong outdoor environments noting peak and average signal strength measurements This must be done in comparison with the antenna supplied in the Development kit Performance results and signal strength measurements must be comparable to the reference antenna supplied Passive antenna signal strength measurements will be lower than an active antenna but time to fix should be comparable 2 6 4 Jupi
30. ows the recommended copper pad dimensions The solder paste mask needs to be adjusted to suit the application s reflow process however a 1 1 paste mask pad size ratio is the recommended starting point gt 1 0 20 gt ke a 16 15 0 8 D EJ S 2 J top view EN of pad layout 10 re all measurements in mm 1 277 Ka D 30 1 1 A 25 4 0 1 Figure 2 3 Recommended application layout dimensions 2 5 2 General recommendations Choice of PCB stack up In general a two layer PCB substrate can be used with all the RF signals on one side Multi layer boards can also be used These design recommendations here only address the microstrip style of RF connection Stripline designs can also be accommodated However long lengths of stripline can cause excessive signal loss and vias in the signal track should be avoided LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 9 Ground plane design We reccomend a complete ground plane is used under the PCB with signal tracks on the same layer as the module We also recommend having a ground plane on both sides of the PCB underneath the module If the ground planes are very small separate analogue and digital grou
31. ply the antenna DC voltage to pad 19 of the module A 2 7V 25mA supply is made available on pad 20 if the chosen antenna can accept that voltage This supply is under the command of the TricklePower energy control 2 4 2 Grounding Separate AGND Analogue Ground and DGND Digital Ground grounds are shown in Figure 2 2 If this grounding method is used the ground planes can be connected underneath the module In some applications with very small ground planes separate ground planes may not be required This should be determined by the application integrator See Section 2 5 2 for ground plane recommendations and design considerations involving the antenna input and the 500 microstrip connection LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice v4 2 4 3 Decoupling The schematic in Figure 2 2 illustrates a suggested method of decoupling These are capacitors C1 to C7 This level of decoupling may not be required in a particular application in which case these capacitors could be omitted Only the signal lines used in the application require decoupling All capacitors are highly recommended if the module will experience substantial electromagnetic interference EMI All low value capacitors should be as close as possible to the module pad with a short connection to the ground plane Any data lines that have not been properly shielded are susceptible to
32. protection and the design and layout of a custom PCB This document outlines the following design considerations and provides recommended solutions Hardware application information This section introduces the system interface and provides the following physical specifications a electrical connections SMT pad interface b mounting PCB pad layout dimensions c manufacturing recommendations d application circuit interface It also discusses the fundamental considerations when designing for RF and presents the antenna system design overview This covers the following topics a PCB layout b antenna system design choices Software application information This section provides answers to some common questions that may not have been covered in the above topics A sample solution is presented and discussed for example purposes only Due to the nature and complexity of GPS signals it is recommended that application integrators adhere to the design considerations and criteria described in this document 2 0 Hardware application information The modules provide 30 Surface Mount pads for electrical connections The sections that follow introduce the physical and relative functional specifications for application integration Note The electrical connections can carry very low level GPS signals at 1 57542 GHz The layout must be designed appropriately with consideration of the frequencies involved 2 1 Electrical connections SMT p
33. rmed while the output is low for this reason The antenna status output message is an NMEA message in the form PTTK ANT d CS Where d represents any of the following numbers d Description normal antenna operation antenna open circuit antenna short circuit antenna disabled antenna sensing disabled due to GPIO override Table 3 4 Antenna status output message values The antenna status message is output automatically in the event of a short circuit or open circuit being detected or an open circuit condition coming to an end In addition this message is output on the receipt of the NMEA input message PSRF199 CS The antenna status is also output as the SIRF binary message with message ID 99 It contains one byte of data being the appropriate value from Table 3 4 This gives a payload length of 2 bytes since the message ID is considered part of the payload The antenna status message is output automatically in the event of a short circuit or open circuit being detected or an open circuit condition coming to an end In addition this message is output on the receipt of the SIRF binary message with message ID 199 The output rate of this message is also under the normal control of the SIRF Binary Query Rate Control input message however this message is not output at a regular rate by default 3 8 Custom application software The module provides custom modification of the firmware to use available CP
34. rol output The Jupiter receiver has a digital input to provide signalling when an antenna fault has occurred These functions are shared with the Jupiter 30 GPIO pads as shown in Table 2 7 pa e Jupiter GPIO function unctions ANT_CTRL GPIO1 ON High ANT_OC GPIO15 Active High NANT_SC GPIO3 Active Low Table 2 7 Antenna sense and control functions The reference design shown in figure 2 11 is indicative of an open circuit switchover threshold of approximately 3 mA This maybe too high for some low power antennae and can be adjusted by changing the following resistor values R7 to 12Q and R3 to 2K2Q This results in an open circuit switchover threshold of approximately 2 mA The over current circuit consisting of Q1 and Q2 is the same as the simple current limit circuit shown in Figure 2 9 providing a 70 mA current limit In addition this design has the following features 1 Q4 A and Q4 B form a low current sensor thus providing a signal to indicate when the antenna has become disconnected or open circuit It is not mandatory to use a matched pair of transistors as shown in this design but it will provide consistent results over a wide temperature range 2 Q3 provides a method for the receiver to turn off the active antenna supply in the event of a fault occurring This is a latched condition in the software and can be restored by issuing a reset or power down 3 Short circuit sensing is achieved by feeding the
35. s a hexadecimal digit 3 5 1 Configure port directions PSRF225 xx xx CS lt CR gt lt LF gt Sets the direction of the GPIO pins The first octet is the mask which ports to override the second the new direction A zero represents an input and a one an output This command must be sent before attempting to manipulate or read any the specified GPIO It also has the effect of suspending the normal port functions on the pins specified Normal operation will resume following a hardware reset including any use of the reset line in Push to Fix mode Response PTTK GPIO DIR xx xx CS 3 5 2 Set outputs PSRF226 xx CS lt CR gt lt LF gt Changes the specified outputs to high Other outputs are not affected There are no changes to any pins that are configured as inputs Response PTTK GPIO SET xx CS 3 5 3 Clear outputs PSRF227 xx CS lt CR gt lt LF gt Changes the specified outputs to low Other outputs are not affected There are no changes to any pins that are configured as inputs Response PTTK GPIO CLEAR xx CS 3 5 4 Read inputs PSRF228 CS lt CR gt lt LF gt Returns the values on the input pins Pins configured as outputs read as zero Response PTTK GPIO READ xx CS This message is sometimes output automatically 3 6 GPS fix output The GPS fix output is an active low output on pin 23 of the module Whenever the unit has either a 2D or a 3D fix this output will be low When the unit has no fix th
36. ter module used as a GPS sensor The adapter board reference design shows how a Jupiter GPS receiver module can be used with an external active antenna via a coax connector The same design can be used with a passive patch antenna on the same PCB It follows the general arrangement described in Section 2 6 3 The module is placed such that the connection between the antenna and the antenna input pad is as short as possible Also note the PCB should have a complete ground plane on the patch side of the board This serves as the ground plane required by the antenna The serial data from the module must be connected to a local host processor and care should be taken such that noise from these devices cannot enter the signal path or GPS antenna It is recommended that all digital devices are placed on the opposite side of the board to that of the antenna LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 13 2 6 5 DC supply protection for an active antenna Antenna DC supply current limit When the Jupiter receiver is used with an external active antenna the DC supply in the coax cable is vulnerable to over current if a fault occurs in the antenna or its cable gets crushed for example in a car door WARNING It is important to note that the module antenna power feed does not have internal current limiting Damage can occur if unlimited current is permitted to
37. w temperature is 265 C for 10 seconds Refer to Figure 2 1 4 Jette PE 8 D D d D D q Bi D D D D D D D d D D D D D D 0 D D i D D 120 140 160 180 200 220 240 260 280 300 TIME SECONDS Figure 2 1 Lead free and tin lead reflow profile recommendation 2 3 2 Connection pad material The 30 surface mount connection pads have a base metal of copper with a gold flash finish This is suitable for a lead free manufacturing process LA000577C 2006 Navman New Zealand All rights reserved Proprietary information and specifications subject to change without notice 6 2 3 3 Solder paste mask size This should be adjusted by experimentation according to the customer s production process requirements A 1 1 paste mask pad size ratio has been found to be successful 2 3 4 Solder paste type The module accepts all commonly used solder pastes The solder paste can be lead based or lead free If a lead free process is introduced factors such as circuit board thickness fabrication complexity assembly process compatibility and surface finish should be taken into consideration 2 3 5 Coating The final PCB may be selectively coated with an acrylic resin airfoven cured conformal coating clear lacquer or corresponding method which gives electrical insulation and sufficient resistance to corrosion 2 3 6 Post reflow washing It is recommended that a low residue solder
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