MS20 GPS Receiver User Manual
Contents
1. 0 650 16 44mm Cl E S 2 PHYSICAL DIMENSIONS 0 111 2 82mm ar 0 040 1 016mm Figure 2 Mechanical Dimensions E Copyright 2011 NavSync Ltd Rights Reserved Specifications subject to change without notice 3 PHYSICAL CHARACTERISTICS continued 3 2 Physical Interface Details The interface to the MS20 is via 0 90 mm castellations on a 1 27 mm pitch There are 25 castellations in all The details of the interface connections are given below 3 3 Pin Out 1 NVDD Primary Supply 3 2 5 0V 2 TX PRIMARY Serial Data Transmit from Module NMEA Output 9600 8N1 3 RX PRIMARY Serial Data Receive to Module 4 GND Ground 5 RESET Active Low Device Reset 6 VBAT Backup Supply 2 2 5 0V Required if no battery connect to primary 7 NC Not Connected CW20 DSUMUX 8 1PPS One Pulse Per Second 9 RX SECONDARY Serial Data Receive to Module CW20 DSU RX 12. 24 10 APPENDICES 2 a E a a EE aa a 25 31 Date N1 Date 1 Description 1 1 Introduction The MS20 uses the physical form factor of the earlier generation CW20 module with changes in the power and voltage requirements The MS20 GPS module is a highly sensitive compact single chip solution for GPS applications It includes an RF receiver complete baseband processor flash memory and a power control unit The RF receiver uses a single conversion low IF digital architecture with the high level integration leaving a few off chip matching and decoupling components minimizing system cost The baseband processor is controlled by adaptive signal processing and the navigation firmware is optimized for execution on a low power microprocessor Optimal signal acquisition and tracking strategy are enabled by sophisticated adaptive control algorithms Sophisticated adaptive control algorithms provide optimal signal acquisition tracking strategy 1 2 Applications PND Mobile Phone UMPC Vehicle Tracking Asset Tracking Personnel Tracking DSC and GPS Related Marine and Timing Navigation 1 3 Features GPS L1 C A code High sensitivity of 159 dBm in tracking amp 144 dBm in acquisition Build in power on reset and calibration circuits Assisted autonomous operation Fast TTFF in all m
3. 60 90 sec Typ 2 min Max 100 50 1 Ramp Slope not to exceed 3 C sec 0 f r 0 50 100 150 200 250 300 35C Time sec Figure 5 Solder Profile 9 ORDERING INFORMATION MS20 Standard Build SBAS not supported Note MSL3 per 1PC JEDEC J STD 020C J STD 033B Please use appropriate processing and handling techniques Copyright 2011 NavSync Ltd Rights Reserved Specifications subject to change without notice 10 APPENDICES Appendix 1 Simple NMEA Checksum Tool Copyright C 2007 2010 C Turvey Navsync Ltd Open Source Licence Free All Rights Reserved MSVC cl 0x nmeasum c include lt windows h gt include lt stdio h gt include lt stdlib h gt POS SOOO SOI ISIS OSIRIS IIH IG Win32 Console Application Compile with MSVC command line cl Ox NMEASUM c A NMEA command can be processed as a single argument they do not contain spaces and you do not need to provide the initial or trailing checksum for example NMEASUM PRTHS U10PALL 0 GSA 1 RMC 1 PRTHS UTOPALL 0 GSA 1 RMC 1 73 NMEASUM PNMRX111 COLD PNMRX111 HOT PNMRX600 INFO PNMRX111 COLD 40 SPNMRX111 HOT 17 PNMRX600 INFO
4. Field 2 Lat Hemi N S Field 3 Longitude DDMMM mmmmm Field 4 Lon Hemi E W Field 5 UTC Time HHMMSS SSS Field 6 Fix A Valid V Not Valid Field 7 Mode A Autonomous D Differential E Estimated N Not Valid Optional Simulator Does not report this sscanf field 1 lf amp lat lat_hemi field 2 0 sscant field 3 lf amp lon lon_hemi field 4 0 sscanf field 5 lf amp fix time valid field 6 0 if valid A ZC Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice NIV 10 APPENDICES continued Appendix 2 continued Extract Time of Fix fix minute int fix time 100 fix second fix time fix minute 100 fix hour fix minute 100 fix minute fix minute 100 Process Latitude DDMM mmmmm lat deg int lat 100 Decompose NMEA form ASCII into DEGREES and MINUTES lat min lat lat deg 100 lat double lat deg lat min 60 0 Computed Latitude in DECIMAL DEGREES if lat hemi S lat_deg lat_deg lat lat Process Longitude DDDMM mmmmm lon deg int lon 100 Decompose NMEA form ASCII into DEGREES and MINUTES lon_min lon lon_deg 100 lon double lon_deg lon_min 60 0 Computed Longitude in DECIMAL DEGREES if lon_hemi W lon_deg lon_deg lon lon printf 4d 9 6If 4d 969 6lf 14 101 14
5. 5 2If 5 2If n pdop hdop vdop GLE RS UR PUR ROR TEM SIUE US UN RIT URC cee Gee erum sum os noms edt vk koe ize int main int argc char argv 1 int i for i 1 i argc i Process each argument as a NMEA sentence DecodeNMEA argv i return 0 M E d C M LL Ql CQ QC X c C Ld Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice INAV D7 MS20 GPS Receiver User Manual Revision Revision Date Notes 05 18 10 User Manual Preliminary Release P01 08 19 10 Oscillator Update 01 20 11 Signal Description Updates NavSync Ltd Europe Bay 143 Shannon Industrial Estate Shannon Co Clare Ireland Phone 353 61 475 666 E mail sales navsync com North America 2111 Comprehensive Drive Aurora IL 60505 USA Phone 630 236 3026 E mail northamerica amp navsync com WWW navsync com
6. 10If 02d 02d 06 3If n lat_deg lat_min lon_deg lon_min lat lon fix_hour fix_minute fix_second else puts Invalid Fix else if stremp field 0 GPGSA 0 amp amp f gt 17 GPS DOP and Active Satellites char mode fix double pdop hdop vdop int i SV Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 10 APPENDICES continued Appendix 2 continued Field 1 A Automatic 3D 2D M Manual Field 2 Fix 1 No Fix 2 20 3 30 Field 3 SV List 1 Field 14 SV List 12 Field 15 PDOP Field 16 HDOP Field 17 VDOP mode field 1 0 fix field 2 0 sscanf field 15 9oIf amp pdop Position Dilution of precision PDOP sscanf field 16 9oIf amp hdop Horizontal Dilution of precision sscanf field 17 9oIf amp vdop Vertical Dilution of precision VDOP switch mode 1 case A puts Mode Automatic break case M puts Mode Manual break default puts Mode Unknown switch fix case 1 puts Fix Not Available break case 2 puts Fix 2D break case 3 puts Fix 3D break default puts Fix Unknown printf SV_ for i 0 i lt 12 i if field 3 i 0 sscanf field 3 i d amp sv printf 3d sv putchar n printf PDOP 5 2If
7. 6 3 General NMEA Format The general NMEA format consists of an ASCII string beginning with a character and terminated with a lt CR gt lt LF gt sequence NMEA standard GPS messaged begin with GP then a 3 letter message identifier MS20 specific messages being with PMST followed by 2 digit number NMEA proprietary message begin with a P The message header is followed by a comma delimited list of fields optionally terminated with a checksum consisting of an asterisk and a 2 digit hex value representing the checksum There is no comma preceding the checksum field All messages emitted by the MS20 have checksums the checksum should be verified before using or relying on the data provided When present the checksum is calculated as a byte wise exclusive OR XOR of the characters between the and the As an ASCII representation the number of digits in each number will vary depending on the number and precision hence the record length will vary Certain fields may be omitted blank if they are not used or available In this case the field position is reserved using commas to ensure the correct interpretation of subsequent fields There are no spaces in NMEA messages When parsing data the routines should be robust and flexible to account for precision changes The NMEA format was de signed as a common interface to position reporting devices in the 1980 s including TRANSIT and LORAN The format of latit
8. Magnetic Variation blank 0 0 Not Used E W Indicator blank 0 0 Mode Indicator char 1 1 A Autonomous N Data Not Valid Checksum XX 0 3 3 2 Hex Digits XOR sum of payload Message Terminator lt CR gt lt LF gt 2 2 ASCII 13 ASCII 10 Table 13 GPRMC Field List Examples GPRMC 215139 980 V 0000 0000 N 00000 0000 E 0 0 0 0 161109 N 74 GPRMC 215207 000 A 4147 9049 N 08816 2642 W 0 0 0 0 161109 A 76 6 11 PMSTO2 Software Reset PMST02 0 04 HOT Device is Restarted PMST02 48 38 WARM Device is restarted invalidate ephemeris PMST02 58 39 COLD Device is restarted invalidate ephemeris and position Table 14 PMSTO2 Software Reset The satellite constellation provides a continuous stream of navigation data modulated on to the pseudo random sequence rang ing signal This data is encoded at 50 bits per second as five 300 bit sub frames Three of these subframes contain ephemeris information which expresses the position of the satellite at a given time and coefficients to extrapolate the position into the future The other two sub frames contain a rolling index of other data including a constellation wide almanac that can roughly estimate the location of satellites months into the future If the receiver knows the current time and rough location it can make approximations about visible satellites from that time location effectively halving the search space required to acquire satellite signals Once the receiver has a
9. s Check the line synchronization if s 0 return Verify the line checksum integrity c 0 checksum i 1 bytes between and but not including those bytes while s i 0 amp amp s i C s i if s i 0 return sscanf amp s i 1 96x amp x Checksum byte Note sscanf needs this to be an int rather than a single byte if c char x amp OxFF Leave if checksum fails return Parse out fields on and f 0 while 1 Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 10 APPENDICES continued Appendix 2 continued field f s while s 0 amp amp s amp amp s amp amp s 0 00 amp amp s 0x0A S if s 0 5 5 0x0D 5 0x0A f FIELD MAX 1 s 0 field f NULL break S 0 if Verbose printf Fields 02d n f 0 1 0 i lt f i printf 02d s n i field i Process a couple of NMEA sentences for illustration if stremp field 0 GPGLL 0 amp amp f gt 6 Geographic Position Latitude Longitude and Time double lat lon int lat_deg lon_deg double lat_min lon_min double fix_time int fix_hour fix_minute double fix_second char lat_hemi lon_hemi valid Field 1 Latitude DDMM mmmmmm
10. 0 TX SECONDARY Serial Data Transmit from Module CW20 DSU TX 11 POWERON Ground to Turn Internal Regulators Off CW20 DSUEN 12 EVENTIN Event Input with Custom Firmware CW20 DSUBRE 13 GPIO General Purpose IO with Custom Firmware CW20 DSUACT 14 WAKEUP Pull High to Suspend 15 RF GND RF Ground 16 RF IN RF Input with 3 0V DC Bias for Active Antenna 17 RF GND RF Ground Copyright 2011 NavSync Ltd Table 3 Pin Out Descriptions All Rights Reserved Specifications subject to change without notice 3 PHYSICAL CHARACTERISTICS continued 3 4 Solder Pad Size and Placement 176766 3001979 300196 4 48986mm 7 62503mm 7 62498mm 05844 1 48438mm 076798 1 95067mm 75616 1 92065mm 19882 5 05003 198818 5 04998mm RECOMMENDED PCB FOOTPRINT 150786 9 89mm 3 82996mm 25197 6 40004mm 0 050 1 27mm d 130778 128414 3 32176mm 3 26172mm b ae 1 27 1 48438 12716 3 22986mm Figure 3 Solder Pad Size and Placement 4 MOIN Nata Shaat Bev PN ata 1 20 11 NS34 DS MS20 Data Sheet Rev P03 Date 01 20 11 AVSY Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice N 4 SIGNAL DESCRIPTIONS 4 1 Signal Descriptions NVDD Type Power Direction Input Pin 1 The supply input This 3 3V input supplies power to RF and digital sections of the MS20 and should be p
11. 27 29 51 1 3 0 7 1 1 38 E Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 6 USER INTERFACE MESSAGES continued 6 7 GPGSV This message transfers information about the satellites in view Each record contains information for up to 4 satellites allowing up to 16 or more satellites from the constellation that are visible to the receiver The list may include one or more geostationary SBAS satellites The data is not guaranteed to be tied to specific channels and satellites may come go as the receiver searches The azimuth and elevation only appear when the receiver knows its location and the location of the satellites with respect to itself The number of records sent will expand and collapse based on the number of satellites and channels changes In the final record of the sequence the unused fields are omitted or left blank with commas to indicate the field has been omitted The GPGSV message structure is shown next Field Format Min Chars Max Chars Notes Message ID GPGSV 6 6 GSV protocol header Number of Messages int 1 1 Number of messages in the sequence 1 to 4 Message Number int 1 1 Sequence number of message in current burst Satellites in view int 1 2 Number of satellites in view this list Satellite ID int 0 2 2 Satellite vehicle 1 5 9 Elevation int 0 1 2 Elevation of satellite in degrees 0 90 Azimuth int o d 3 Azi
12. 4D static const char Hex 0123456789ABCDEP ME EREE ERRES Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice N AV 10 APPENDICES continued Appendix 1 continued void NMEAMessage unsigned char s int i int j int Len BYTE Checksum BYTE Buffer 300 Len strlen s j 0 Buffer j Add Initial Checksum 0 Zero checksum for i 0 i lt Len i Compute XOR checksum across body Checksum unsigned char s i Butfer j s i Buffer j Add termination Buffer j Hex Checksum gt gt 4 amp OxOF Add hexidecimal checksum Buffer j Hex Checksum gt gt 0 amp OxOF Buffer j r Add CR LF Buffer j n Buffer j 0 puts Buffer int main int argc char argv 1 int i for i 1 i argc i Process each argument as a NMEA sentence NMEAMessage argv i return 0 JJ S REFERERES mS CUN NI IRL ae Ee ea RUNG el RCRD NT Oe eae TOI lite ae Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 10 APPENDICES continued Appendix 2 PE ATS e gig sd ngo eges UE Kos n e Simple NMEA Parsing Tool Copyright C 2007 2010 C Turvey Navsync Ltd Open Source Licence Fr
13. C GPGSV 4 3 14 04 11 304 49 11 04 200 51 48 161 48 47 205 75 GPGSV 4 4 14 35 42 218 47 12 254 74 Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 6 USER INTERFACE MESSAGES continued 6 8 GPVTG This message transfers the velocity and tracking over ground information The GPVTG message format is shown below Field Format Min Chars Max Chars Notes Message ID GPVTG 6 6 VTG protocol header Course True float 1 1 3 2 Measured heading in degrees Reference char 0 1 1 T Stands for true heading Course Magnetic blank 0 0 Not used magnetic heading in degrees Reference char 0 1 1 M Stands for magnetic Speed float 1 1 4 2 Speed in knots Units char 0 1 1 N stands for nautical knots miles per hour Speed float 1 1 4 2 Speed in KPH Units char 0 1 1 K Stands for kilometers per hour Mode Indicator char 1 1 A Autonomous N Data not valid Checksum XX 0 3 3 2 hex digits XOR sum of payload Message Terminator lt CR gt lt LF gt 2 2 ASCII13 ASCII10 Table 11 GPVTG Field List Examples GPVTG 0 0 T M 0 0 N 0 0K N 02 GPVTG 0 0 T M 0 0 N 0 0 K A 0D GPVTG 179 98 T M 97 09 N 179 81 K A 02 GPVTG 315 03 T M 97 23 N 180 07 K A 08 6 9 GPZDA This message transfers the internal timing information The GPZDA message format is shown below Field Format Min Chars Max Chars Notes Message ID GPZDA 6 6 ZDA protocol header UTC Tim
14. MS20 GPS Receiver User Manual Issue P03 Bulletin NS34 UM 5 228 Ws IDESCRIPTION 3 E MEM eligere COM E E 3 k2 62 Rs 3 1 9 IMS2O Feal les dee tea er ato ee amc ea deae dade 3 2 SPECIFICATION e H 4 5 V2 EN Tee Thur ialo tter 4 22 Electrical GharacterisSli6S oo uci Genesis 5 2 9 Absolute Peres rece ead a tpe D a eS 5 ee 5 3 JPHYSICAL CHARACTERISTIGS 5 nire ee ier aa ED SS EE EX YQ NF 6 8 Forms And SILO E 6 3 2 Physical Interface Detalle ieu suc terne a ESE OTU E ARE I SM NEL MOLD 7 34 Solder Pad E a e 8 4 SIGNAL DESCRIPTION e 9 4X Powersignal DESCHIPUOMS ernea tees Cub iaeiae REO ai re 9 5 SPECIAL CONSIDERATIONS ion evene E AEAEE NE aE ASAE 10 521 Power Enable citer a betae rte co een Done dieu ee Yee e eee 10 BZ ACSC IRE ERE DIL LT 10 O 10 5 4 Batory SUpDly 10 55 FitmwareW pdating EUR 10 6 WUSERINTERFACE MESSA GE S iei E
15. S continued 6 13 PMST200 Command Acknowledgement This message is emitted in response to certain configuration and command requests If an error code is returned the command request failed to meet internal sanity checks or was otherwise malformed For example a reset without a control field PMST02 18 will result in a 202 error response negative acknowledge PMST200 02 202 1A Field Format Min Chars Max Chars Notes Message ID PMST200 8 8 Acknowledge header Command ID int 0 1 2 Command being acknowledged Error Code int 0 3 Blank or 0 for success 202 for failure Checksum XX 0 3 3 2 hex digits XOR sum of payload Message Terminator lt CR gt lt LF gt 2 2 ASCII 13 ASCII 10 Table 16 PMST200 Field List Examples PMST200 02 2A PMST200 02 202 1A 6 14 PMST12 Changing Periodicity and Baud Rates Non Permanent The speed and rates on the receiver can be changed in a non permanent manner until the receiver is reset When changing baud rates one should be aware of the amount of data that is expected from the receiver If more than 480 bytes of data are being sent at each second the 4800 baud rate is not appropriate Before selecting lower baud rates the sentences and periodicity should be culled Higher baud rates also permit lower latency in receiving the data Remember GPS measurements are made at defined intervals one second these measurements are then solved to provide a location solution and finally transmitte
16. avSync Ltd All Rights Reserved Specifications subject to change without notice CONDO C 6 USER INTERFACE MESSAGES continued 6 16 PMST10 The baud rates may also be changed on both of the serial ports Slower baud rates should work but their use is not recom mended and such applications will not be supported Specifically it is hard to provide comprehensive data at a lower rate as the sentence s periodicity must be reduced or completely culled to achieve the bytes per second budgets This lack of informa tion will make debugging and diagnostics difficult and will increase the latency between the taking of measurements and the reception of results The two serial ports may be programmed to different speeds however in standard software builds the data output by both will be the same The sentences and periodicity cannot be configured differently for different ports The secondary output is de signed to permit a debug diagnostic connector to monitor the receiver externally to the system to which it is installed Providing a pin header to expose this debug port is strongly recommended PMST10 Port Baud Stop Flow Bits Parity Port Stop 0o LBGD 0 0 COMO Primary 0 1StopBit 1 Debug 1 2 Stop Bits Baud Flow 0 300 Unsupported 0 None 1 X 600 Unsupported 1 Xon Xoff Unsupported 2 __ 1200 Unsupported 2 RTS CTS Unsupporte
17. cksum is either blank or 3 digits All messages currently emit a checksum When a value is signed this is represented by followed by the number of digits 6 4 GPGGA This message transfers global positioning system fix data The GPGGA message structure is shown below Field Format Min Chars Max Chars Notes Message ID GPGGA 6 6 GGA protocol header UTC Time hhmmss sss 2 2 2 3 2 2 2 3 Fix time to 1ms accuracy Latitude ddmm mmmm 2 2 4 2 2 6 Degrees 100 Minutes Nominally 4 decimal places N S Indicator char 1 1 N North or S South Longitude dddmm mmmm 3 2 4 3 2 6 Degrees 100 Minutes Nominally 4 decimal places E W Indicator char 1 1 E East or W West Position Fix Indicator int 1 1 O Fix not available or invalid 1 GPS SPS mode Fix available 2 DGPS SPS mode Fix available SBAS Satellites Used int 2 2 Number of satellites used to calculate fix 00 12 HDOP float 1 1 3 1 Horizontal Dilution of Precision MSL Altitude float 1 1 5 1 Altitude above Mean Sea Level Units char 1 1 M Stands for Meters Metres Geoid Separation float 0 1 4 Separation from Geoid WGS84 can be blank Units char 1 1 M Stands for Meters Metres Age of Differential int 0 1 5 Age in seconds Blank NULL on MS20 Corrections SBAS operation reflected in fix indicator Differential Reference int 0 4 4 Blank NULL Zero or Station ID Station ID Checksum XX 0 3 3 2 Hex Digits XOR sum of pa
18. d 3 2400 Unsupported 4 4800 5 9600 Bits 6 19200 0 8DataBits 7 38400 1 7 Data Bits 8 57600 9 115200 Parity 0 No Parity 1 Odd Parity 2 Even Parity Table 18 PMST10 Port Baud Stop Flow Bits Parity For example setting the NMEA output of the debug port to 19200 8N1 PMST10 1 6 0 0 0 0 1C Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 6 USER INTERFACE MESSAGES continued Changing periodicity and baud rates permanent 6 17 PMSTO9 The setting within non voltatile memory can be changed in a two step process The initial step is to configure the desired settings and the second is to commit thoses setting to non volatile flash memory and to start using them Serial Baud Rates PMSTO9 Parameter Setting Parameter 1 COMO Primary 2 COMI Debug Setting 2400 Unsupported 4800 9600 14400 Unsupported 19200 28800 Unsupported 38400 57600 115200 co IN SD O1 A JO N O Table 19 Serial Baud Rates PMSTO09 Parameter Setting Parameter 8 RMC 9 GGA 10 GLL 11 GSA 12 GSV 14 VIG 15 ZDA _ Setting 0 Disable 9 Once every 10 seconds 4 1 Hz Once every second A every 15 seconds 5 1 2 Hz Once every 2 seconds B Once every 20 seconds 6 1 3 Hz Once every 3 seconds C every 30 seconds 7 4 4 Once every 4 seconds D Onceevery6Osec
19. d to the host Measurements will have occured in the past If the receiver is moving it will be in a different location by the time you process the data Recognize that you may need to extrapolate interpolate the location information using course over ground direction and speed over ground velocity to estimate the location at a different time One should also be aware that computing a GPS solution is an iterative process of trilateration expanding overlapping spheres measuring time of travel of the wave front for multiple satellites traveling at orbital speeds That is to say that although a receiver may be static everything else in the system is moving rapidly Even if you reduce the output rate of the messages from the receiver the receiver will continue to track the satellite signals and update it s internal measurements and solutions Reducing the data output from the receiver will not signifi cantly reduce power consumption beyond that used by the serial transmission circuitry The maximum output rate supported is 1 Hz The output of individuals messages can be turned off or set with a periodicity of 1 2 3 4 5 10 15 20 30 or 60 seconds Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 6 USER INTERFACE MESSAGES continued 6 14 PMST12 continued PMST12 Sentence Frequency Sentence Frequency 0 0 Disable 1 GGA 4 1Hz Once every
20. e hhmmss sss 2 2 2 3 2 2 2 3 Internal time to 1ms accuracy UTC Day dd 2 2 01 to 31 Day of Month UTC Month mm 2 2 01 to 12 Month of Year UTC Year yyyy 4 4 1980 2079 Likely to exceed viability of constellation Local Zone Hours int 2 2 Not used 00 Local Zone Minutes unsigned 2 2 Not used 00 Checksum XX 0 3 3 2 hex digits XOR sum of payload Message Terminator lt CR gt lt LF gt 2 2 ASCII 13 ASCII 10 Table 12 GPZDA Field List Examples GPZDA 215139 980 16 11 2009 00 00 56 E Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 6 USER INTERFACE MESSAGES continued 6 10 GPRMC This message transfers recommend minimum specific GNSS data The GPRMC message format is shown below Field Format Min Chars Max Chars Notes Message ID GPRMC 6 6 RMC protocol header UTC Time hhmmss sss 2 2 2 3 2 2 2 3 Fix time to 1ms accuracy Status char 1 1 A Data Valid V Data Invalid Latitude ddmm mmmm 2 24 2 2 6 Degrees 100 Minutes Nominally 4 decimal places N S Indicator char 1 1 N North or S South Longitude dddmm mmmm 3 2 4 3 2 6 Degrees 100 Minutes Nominally 4 decimal places E W Indicator char 1 1 E East or W West Speed Over Ground float 1 1 5 3 Speed Over Ground SOG in knots 1 Knot 1852 m Course Over Ground float 1 1 3 2 Course Over Ground COG in degrees Date ddmmyy 2 2 2 2 2 2 Current Date 1980 2079
21. econdary RX 9 and TX 10 pins should be exposed to a header The software to update the device runs on a PC These pins are not RS 232 compatible so direct connection to a PC is not possible although there are several level converters and USB type adapters to achieve this It is suggested that the header match off the shelf or other converters you are currently using E Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 6 USER INTERFACE MESSAGES The following application protocols are implemented 6 1 NMEA Protocol The MS20 software is capable of supporting the following NMEA message formats NMEA Message Prefix Format Direction GPRMC Recommended minimum specific GNSS data Out GPGGA GPS fix data Out GPGLL Geographic position latitude longitude Out GPGSA GNSS DOP and active satellites Out GPGSV Satellites in view Out GPVTG Velocity and track over ground Out GPZDA Date and time Out Table 5 NMEA Messages Summary 6 2 NMEA Extensions The MS20 software is capable of supporting the following NMEA extensions NMEA Extension Prefix Format Direction PMST02 Software reset In PMST12 NMEA message rate control In PMST10 NMEA Baud rate control In PMSTO9 Non voltatile settings In PMST14 Polling specific NMEA messages In PMST100 Software version information Out PMST200 Command acknowledgement Out Table 6 Extended Messages
22. ee All Rights Reserved MSVC cl parse c POR OCHS ISOS ISIS IIIS ISSR IIIS CII I ISO III I IC include lt windows h gt include lt stdio h gt include lt stdlib h gt include lt math h gt POR OSES SISOS EIS SII SISSIES GEIS ISIS III I IC Win32 Console Application Compile with MSVC command line cl Ox PARSE c PARSE GPGLL 4157 209646 N 08844 518354 W 153731 845 A A 46 DecodeNMEA GPGLL 4157 209646 N 08844 518354 W 153731 845 A A 46 Fields 08 00 GPGLL 01 4157 209646 7 02 N 03 08844 518354 04 W 05 153731 845 7 06 A 07 A 41 57 209646 88 44 518354 41 9534941000 88 7419725667 15 37 31 845 iff SES ae eames Fe SR Teo NUES pa ty UO Oy UR MOSS SOIN he Caen USC Te USUS REOR US eT UN int Verbose 1 This code is provided for demonstational purposes additional coding and testing would be required for more general use p gu ORES DM Lu d i M C M Deed Parse j000X XX Xx xx format sentences Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice NAV 10 APPENDICES continued Appendix 2 continued define FIELD MAX 100 void DecodeNMEA char s char field FIELD_MAX int f int i char int X if Verbose puts DecodeNMEA printf s n
23. ee Ene DEI Ehre eM ean E Dee 11 22 Gill NMEA Protocol istae eue cece Mere Lu ite eed etd Lp ILU dee 11 62 NMEA Extension eredi cose eost oo topte Saut Eoi cepe ire 11 6 3 General NMEA Formal eere etse icones oe pecia nde inte Ug 11 64 SG PGA iq eee sepes 12 6 5 EE 13 6 6 elec 14 07 SGBAOSVLE I IE a 15 5 8 RN Ge 16 C9 MUERE IM M ML IS 16 woes 17 SE S PMSTD2 cec tM uA i e t tr E LE 17 18 6 12 SPMSTTOO ci itia eee detecta tha iei ed tene ides aee oeste at dpa eser apros eR vd 18 519 PMST200U 19 64 tede tes tt tede oot nee Fits eats 19 20 615 PEMS TIA e s iter nete genase ene avian rte E De 20 6 MIS 21 22 7 AND REEL 23 8 SOLDER PROFILE 24 9 ORDERING INFORMATION
24. ernal regulator is less than 2 7V This clamping will persist for at least 100ms after the supply has recovered This behavior is designed to ensure the correct startup of the re ceiver Be aware that connecting RESET to other external reset inputs will result in the device resetting as well or be held in reset when the power to the MS20 is removed or disabled This situation may occur in several ways NVDD is currently below the drop out threshold of the regulator which is below the minimum input voltage specification NVDD or VDD30 2 9V has browned out because the supply has drooped or otherwise failed to provide enough current on demand the POWERON pin has been or is pulled low or external circuitry either a POR or GPIO is initiating or holding the device in reset Note The internal supplies on the MS20 are not exposed to the user of the device 5 3 Wake Up The WAKEUP 14 Pin is pulled low internally driving this pin high will cause the MS20 to enter the sleep suspend state The MS20 will exit the sleep suspend state when the pin is released or driven low 5 4 Battery Supply GPS receivers use batteries to maintain time and non volatile memory In order to speed up reacquisition GPS receivers want to maintain time date location information along with almanac data The satellite constellation is in constant motion so in order to predict which satellites will be visible you need to know what time it is where you are approximately a
25. muth of satellite in degrees 0 360 SNR int 0 1 2 Signal to noise ratio in dB Hz null not tracking Satellite ID int 0 2 2 Satellite vehicle 2 6 10 Elevation int 0 1 2 Elevation of satellite in degrees 0 90 Azimuth int 0 1 3 Azimuth of satellite in degrees 0 360 SNR int 0 1 2 Signal to noise ratio in dB Hz null not tracking Satellite ID int 0 2 2 Satellite vehicle 3 7 11 Elevation int 0 1 2 Elevation of satellite in degrees 0 90 Azimuth int 0 1 3 Azimuth of satellite in degrees 0 360 SNR int o d 2 Signal to noise ratio in dB Hz null not trackin Satellite ID int 0 2 2 Satellite vehicle 4 8 12 Elevation int 0 1 2 Elevation of satellite in degrees 0 90 Azimuth int o d 3 Azimuth of satellite in degrees 0 360 SNR int 0 1 2 Signal to noise ratio in dB Hz null not tracking Checksum XX 0 3 3 2 hex digits XOR sum of payload Message Terminator lt CR gt lt LF gt 2 2 ASCII 13 ASCII 10 Table 10 GPGSV Field List Examples GPGSV 1 1 00 79 GPGSV 1 1 01 17 41 7B GPGSV 2 1 08 01 51 02 50 12 50 04 49 7F GPGSV 2 2 08 05 51 13 46 18 23 10 50 7C GPGSV 3 1 12 21 63 309 51 27 17 133 46 26 04 206 45 18 47 271 50 7E GPGSV 3 2 12 05 19 068 47 22 13 260 47 29 34 197 49 06 09 322 41 79 GPGSV 3 3 12 15 63 074 53 10 08 070 44 09 09 146 44 51 37 207 51 72 GPGSV 4 1 14 20 70 191 51 23 59 339 50 16 47 078 50 13 30 305 50 7C GPGSV 4 2 14 24 23 264 49 01 17 091 49 25 16 052 49 27 14 245 25 7
26. nd have a way to compute the orbital position of all the satellites within the constellation Using this information the receiver can commit correla tors to search for satellites that are in view and improve the time to first fix TTFF That said today s receivers can search the signal space for the satellite signals much more rapidly than when the system was initially conceived Non volatile memory can also hold ephemeris and almanac information which would otherwise have to be demodulated from the slow data signal The GPS receiver will still be able to function without this information at startup It will just have to do more work and will typically take longer to do so Given the separation of the supplies and to permit the greatest flexibility in application circuits power needs to be present on VBAT for the MS20 to function Without power the MS20 will not start In some implementations it is not desirable to have a battery or super capacitor in the receiver sub system In these situations VBAT and NVDD should be connected together When the main supply is lost any time location and associated data previously held will be lost The receiver can regenerate and reacquire this data although it will take longer With a battery primary cell or rechargeable or super capacitor the voltage at VBAT should be 2 2 V or higher for the MS20 to function 5 5 Firmware Updating In order to perform firmware updates or apply custom firmware the s
27. nsitivity dBm 159 dBm 6 Acquisition Sensitivity SBAS Satellites dBm TBD 7 Tracking Sensitivity SBAS Satellites dBm TBD 7 Static Accuracy without SBAS 50 Confidence CEP 1 7m 8 95 Confidence 2 9m Static Accuracy with SBAS 50 Confidence CEP 1 2m 9 95 Confidence 2 4m Maximum Horizontal Speed 515 m s 1000 Knots 10 Maximum Altitude 18 Km 60000 feet 10 Maximum Acceleration Jerk 4 g 7 g s Power During acquisition fully active amp 3 3V 145 mW While tracking fully active 3 3V 110 mW During Sleep Mode NVDD TBD VBAT Current 25ya Q 3v Interfaces 1 0 Port UART x 2 9600 8N1 Protocols NMEA 0183 Antenna Configuration Supported Active or Passive Impedance 500 Voltage 2 8 3 1V Table 1 Performance Specifications Notes 1 Typical listed 6 Simulator Test continuous fix with all signals at specified power level 2 These are RMS values 7 Simulator Test with signal at specified power level 3 Maximum Sensitivity 147 dBm 8 Open sky 24 hrs statistic active antenna signal range is between 30 to 49 dB Hz 4 Simulator Test all signals at specified power level 9 Open sky 24 hrs statistic active antenna WAAS signal used 5 Estimated 10 Limited by International Traffic in Arms Regulation ITAR E Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 2 2 Electrical Characteristics 2 2 1 Absolute Ratings Symbol Min Typ Ma
28. nued 6 6 GPGSA This message transfers DOP Dilution Of Precision and active satellite information The GPGSA message structure is shown below Field Format Min Chars Max Chars Notes Message ID GPGSA 6 6 GSA protocol header Mode char 1 1 M Manual forced to operate in selected mode 2D 3D A Automatic switching between modes Mode int 1 1 1 Fix not available 2 2D Fix 3 30 Fix Satellites Used int 0 2 2 SV on Channel 1 Satellites Used int 0 2 2 SV on Channel 2 Satellites Used int 0 2 2 SV on Channel 3 Satellites Used int 0 2 2 SV on Channel 4 Satellites Used int 0 2 2 SV on Channel 5 Satellites Used int 0 2 2 SV on Channel 6 Satellites Used int 0 2 2 SV on Channel 7 Satellites Used int 0 2 2 SV on Channel 8 Satellites Used int 0 2 2 SV on Channel 9 Satellites Used int 0 2 2 SV on Channel 10 Satellites Used int 0 2 2 SV on Channel 11 Satellites Used int 0 2 2 SV on Channel 12 PDOP float 0 1 1 3 1 Position Dilution of Precision 3D HDOP float 0 1 1 3 1 Horizontal Dilution of Precision 2D VDOP float 0 1 1 3 1 Vertical Dilution of Precision Up Down Checksum XX 0 3 3 2 Hex Digits XOR sum of payload Message Terminator lt CR gt lt LF gt 2 2 ASCII 13 ASCII 10 Table 9 GPGSA Field List Examples GPGSA A 2 02 04 05 4 7 4 6 0 9 38 GPGSA A 3 01 04 13 16 20 23 24 25 1 8 1 2 1 4 3F GPGSA A 3 05 06 09 10 15 18 21 22
29. odes a typical outdoor hot start in 1 5s warm start in 32s cold start in 35s Up to 60 000 simultaneous search windows 48 acquisition amp 12 tracking channels SBAS WAAS EGNOS MSAS capable Support standard NMEA 0183 TCXO amp RTC integrated Integrate a high performance MIPS M4K CPU Integrated a 512 kB NOR flash memory Easy to integrate UART data interface e 3 3V tolerant I O pins 1 PPS 200 ns RMS 3 2 5V Supply Operates at 1 2V 3 0V core IO integrate LDO Battery backed RAM amp RTC and direct connection 0 18um CMOS for RF and 0 11um CMOS for Baseband Avg current 33mA 3 3V 29mA 5V 21 0x 16 44 x 2 82 mm Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 2 SPECIFICATIONS 2 1 Performance Physical Module Dimensions 21mm D x 16 44mm W x 2 82mm 2mm Notes Electrical Supply Voltages 3V3 NVDD 2V5 VBAT 1 Operating Temperature Range 30 C to 70 C Storage Temperature Range 40 to 85 C GPS Performance GPS Channels 12 tracking 48 acquisition Frequency 1575 42 MHz L1 C A Code TIFF Cold Start 34 seconds 2 8 TTFF Warm Start 32 seconds 2 8 TTFF Hot Start 1 5 seconds 2 8 Re acquisition time 1 seconds 3 Acquisition Sensitivity fix not available TTFF Hot with all signals at 138 dBm 30 s 4 Acquisition Sensitivity dBm 144 dBm 5 Tracking Se
30. onds 0 1 1 _ 8 1 5 Hz Once every 5 seconds Table 20 Message Rates After one or multiple changes in configuration are accumulated they can be committed or burned into flash memory with a single operation PMSTO09 0 0F Write to Flash Settings Area E Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 7 TAPE and REEL SPECIFICATIONS 1 5 2d Kop 4 00 2 00 0 10 x M LK KIC AEZKERA 14 20 0 10 W e 28 40 Bo 9 6 6 6 O 6 amp o 6 6 9o o 6 e I C X L 2 00 Min Section DIMENSIONS Ao 16 70 0 10 Bo 21 80 0 10 Ko 3 80 0 10 NOTES P 24 00 0 10 ALL DIMENSIONS IN MILLIMETERS 10 SPROCKET HOLE PITCH CUMULATIVE TOLERANCE 0 20 l 0 35 0 05 MATERIAL CONDUCTIVE POLYSTYRENE w 32 00 0 30 CAMBER NOT TO EXCEED 1 0mm IN 250mm Figure 4 Tape amp Reel Specifications Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 8 SOLDER PROFILE 300 250 Peak Temp o 245 255 C for 15 sec 200 o Reflow Zone amp 150 30 90 sec a Soaking Zone K
31. quired a satellite it will then attempt to demodulate the data signals and recover the ephemeris data If the receiver already has this data it will save between 18 36 seconds and will be able to make measurements immedi ately after it has signal and timing lock with the satellite Each subframe contains timing information both in it s header and instrincally in the bit timings and those of the underlying pseudo random sequence and the carrier itself T Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 6 USER INTERFACE MESSAGES continued 6 11 PMSTO2 continued In this context the receiver can be reset in several ways A HOT reset is where all the hardware is restarted and the signal is then reacquired Information about the current time location and ephemeris is retained in RAM to permit a quick re establishment of a GPS fix A WARM reset is one where additional information is invalidated Primarily the ephemeris data providing information of the current future estimations of the satellites position Once the receiver re acquires the satellite s it will have to extract the ephemeris data which will add 18 36 seconds of additional delay in ideal conditions before it can provide measurements into the solution engine A COLD reset is similar to a hard start of the receiver when no supplemental data is available The absence of position and or time means that the receiver must search
32. re GPIO Type Direction Output Pin 13 General Purpose IO with custom firmware WAKEUP Type Power Direction Input Pin 14 Pull high to suspend Internal 47k pull down to GND GND Type Power Additional GND Pins for the MS20 Pins 15 17 25 ANT Type Antenna Primary Antenna Connection Pin 16 3V DC Bias Table 4 Signal Descriptions Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 5 SPECIAL CONSIDERATIONS 5 1 Power Enable The POWERON 11 pin is pulled high internally and gates the enable of the internal regulators When high the regulators will be enabled The user may clamp this pin to ground to disable the internal regulator A side effect of this and to effectively per form a Power On Reset POR the Reset pin will be clamped to zero during the time POWERON is low and for at least 100 ms after POWERON is high as the regulator resumes normal operation The POR circuit is monitoring the output from the internal regulators not the NVDD supply Holding POWERON will cause the least amount of power to be consumed by the MS20 via the NVDD pin The CPU flash RF front end and TCXO will be powered down The RTC and its oscillator will continue to be powered from the VBAT pin 5 2 Reset The RESET 5 pin is an open collector pin designed to be clamped low by external circuitry when a reset is required It will also be clamped low internally by the MS20 when the output from the int
33. roperly filtered TX Type Signal Direction Output Pin2 The UART transmit signal for the MS20 RX Type Signal Direction Input Pin 3 The UART receive signal for the MS20 GND Type Power Direction Input Output Pin 4 The ground pin for the MS20 The return path of the NVDD and ground reference for all signal pins RESET Type Control Direction Input Output Open Collector Pin 5 The system reset signal This asynchronous signal must be held low for a minimum of 1ms following valid power on the NVDD pin to generate a device reset Internal 47k pull up to 3V VBAT Type Power Direction Input Pin 6 The backup battery supply input Minimum voltage of 2 2V required to maintain NVRAM settings and power on device nc Type Direction No connect Pin 7 Debug and programming interface GPIO lt 4 gt Type Signal Direction Input Output Pin 8 Blinks for 1ms every time traffic is generated on the UART interface May be left unconnected General purpose input output pin The signal return path is Pin 4 RX SECONDARY Type Direction Input Pin 9 Debug and programming interface TX SECONDARY Type Direction Output Pin 10 Debug and programming interface POWER ON Type Direction Input Open Collector Pin 11 Ground to turn off normally pulled high Internal 47k pull up to NVDD EVENT IN Type Direction Input Pin 12 Event input with custom firmwa
34. second 2 GLL 5 1 2 Hz Once every 2 seconds 3 GSA 6 1 3 Hz Once every 3 seconds 4 GSV 7 1 4 Hz Once every 4 seconds 6 VIG 8 1 5 Hz Once every 5 seconds 7 ZDA 9 Once every 10 seconds A Once every 15 seconds B Once every 20 seconds C Once every 30 seconds D Once every 60 seconds E Update Mode nm Request Mode Table 17 PMST12 Sentence Frequency For example GPGLL once every 10 seconds PMST12 2 9 12 responds with PMST200 12 2B For example GPGGA off PMST12 1 0 18 responds with PMST200 12 2B For example GPGGA polled PMST14 1 02 responds with PMST200 14 2D and GPGGA in the next epoch 6 15 PMST14 Polling Specific NMEA Messages The speed and rates on the receiver may be changed with the PMSTO9 and PMST12 commands If these rates are not suit able for you application or you need and immediate and current response you can request the sentence you want to receive and a single copy will be sent along with an acknowledgement of the request For example you might turn all sentence reporting off and then selectively request a GPGLL sentence when a position update is required This will not save a significant amount of power as the GPS computation is continuous but might simplify parsing PMST14 Sentence Sentence RMC GGA GLL GSA GSV VTG ZDA PMST100 For example GPGGA polled PMST14 1 02 responds with PMST200 14 2D and GPGGA in the next epoch 4 Copyright 2011 N
35. the entire constellation signal space to determine which signals can be acquired Satellites which are not visible to the receiver will also be searched for and the receiver will cycle through all possible satellites skipping from one to the next until it finds signals it recognizes The receiver has multiple correlators so much of this searching will occur in parallel Once the receiver has enough position and timing information it can utilize almanac data to refocus the search on the most probably visible satellites The searching algorithm is mostly transparent to the user and visible primarily as the receiver dwelling and cycling through satellite numbers on uncommitted receiver channels 6 12 PMST100 Software Version Information This message is emitted at startup and reflects the version numbers of hardware and software portions of the implementation The receiver contains a boot ROM which either acts as a boot loader for an empty device or executes a program stored within the flash memory of the receiver Additional library code for high speed math is also contained within the ROM as this memory is fast single cycle and tightly coupled to the internal 32 bit CPU The firmware flash memory is divided into multiple pieces there is kernel code that takes control of the system from the boot ROM an area for storing non volatile settings and a large area to store the application code that implements the GPS solution The version numbers and b
36. ude and longitude was specifically designed for easy transfer to LED 7 segment type display devices with little translation by simple processors The format of degrees and minutes is not immediately intuitive and needs to be decomposed to arrive at a decimal degrees form used in computer software navigation applications The NMEA messages report position ina DDDMM mmmm form The MM mmm portion needs to be divided by 60 to compute the fractional degrees and the DDDxx integer portion needs to be divided by 100 The sign is then negated if the hemisphere is S outh of the Equator or W est of the Greenwich Meridian depending on the latitude or longitude Incorrect decomposition will produce results with significant offsets Example code is available upon request The validity field of the specific NMEA message should always be checked prior to using location infor mation The GPS constellation uses the WS85 datum UE Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 6 USER INTERFACE MESSAGES continued The following tables indicate the maximum and minimum widths of the fields to allow for buffer size allocation The field width specifications represent the minimum and maximum digits of precision which must be present When a field may be omitted this is represented by 0 for omitted blank followed by the data when the field is not emitted For instance 0 3 for check sum means the che
37. uild timestamps for the kernel and application code is provided in this message There is also a checksum for the settings burned into the flash memory The message may be polled at run time by using 59 14 8 Field Format Min Chars Max Chars Notes Message ID PMST100 8 8 Startup header HW Version Major int 0 2 Hardware version nominally 00 HW Version Minor int 0 2 Hardware version nominally 01 App Version Major int 0 2 Firmware application version nominally 05 5 12 App Version Minor int 0 2 Firmware application version nominally 12 Legacy Field int 0 1 Ignore nominally 2 Legacy Field int 0 1 Ignore nominally 1 Kernel Version Major int 0 2 Firmware kernel version nominally 02 2 01 Kernel Version Minor int 0 2 Firmware kernel version nominally 01 Settings Checksum hex 0 4 Four digit hexadecimal checkum Customer ID int 0 3 Customer Id nominally 000 Customer Version int 0 3 Customer version nominally 001 Application Date mmddhh 2 2 2 2 2 2 2 2 Application date Kernel Date yymmddhh 2 2 2 2 2 2 2 2 Firmware kernel date Checksum 0 3 3 2 hex digits XOR sum of payload Message Terminator lt CR gt lt LF gt 2 2 ASCII 13 ASCII 10 Table 15 PMST100 Field List Examples PMST100 01 00 05 12 2 1 02 01 F8CC 000 001 10041415 08030520 77 E Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 6 USER INTERFACE MESSAGE
38. x Units Notes NVDD 0 2 5 5 V VBAT 0 2 5 5 V 1 Notes 1 Absent a battery this should be connected to NVDD Below minimum voltage module will not power up 2 2 3 Recommended Symbol Min Typ Max Units Notes Temp 30 25 70 C NVDD 3 2 3 6 5 0 V VBAT 2 2 3 6 5 0 V 1 Notes 1 Absent a battery this should be connected to NVDD Below minimum voltage module will not power up 2 2 3 CMOS Interface Levels Symbol Min Typ Max Units Notes VCC30 2 9 5 VOH VCC30 0 1 V 1 VOL 0 1 1 Output Current 4 0 mA VIH 2 5 E V 1 VIL 08 V 1 Input Capacitance 5 pF Input current 1 0 uA Notes 1 Digital Inputs and Outputs are 3V CMOS 2 3 Block Diagram Antenna Connection RF GND RF IN RF GND Tables 2 Electrical Characteristics Antenna Power GPS RF Front End nterface amp LNA GPS Baseband Processor Memory Interface AVDD 3 0V Volt DVDD 1 2V Reg Figure 1 MS20 Block Diagram Digital O Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 3 PHYSICAL CHARACTERISTICS 3 1 Form and Size The MS20 is a multi chip module built on an FR4 fiberglass PCB All digital and power connections are via castellations on the 21 x 16 44 mm PCB The general arrangement of the MS20 is shown in the diagram below 0 827 21 00mm
39. yload Message Terminator lt CR gt lt LF gt 2 2 ASCII 13 ASCII 10 Table 7 GPGGA Field List Examples GPGGA 215139 980 0000 0000 N 00000 0000 E 0 00 0 0 M M 0000 61 GPGGA 215204 000 4147 9057 N 08816 2623 W 1 05 3 4 247 8 M 43 5 M 0000 65 GPGGA 215253 000 4147 9055 N 08816 2649 W 2 08 1 2 242 1 M 43 5 M 0000 6F a Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 6 USER INTERFACE MESSAGES continued 6 5 GPGLL This message transfers geographic position latitude longitude and time The GPGLL message structure is shown below Field Format Min Chars Notes Message ID GPGLL GLL protocol header Latitude ddmm mmmm Degrees 100 Minutes Nominally 4 decimal places N S Indicator char N North or S South Longitude dddmm mmmm Degrees 100 Minutes Nominally 4 decimal places E W Indicator char E East or W West UTC Time hhmmss sss Fix time to 1ms accuracy Status char A Data Valid V Data Invalid Mode Indicator char A Autonomous N Data Not Valid Checksum XX 0 3 3 2 Hex Digits XOR sum of payload Message Terminator lt CR gt lt LF gt 2 2 ASCII 13 ASCII 10 Table 8 GPGLL Field List Examples GPGLL 0000 0000 N 00000 0000 E 215139 98 V N 7D GPGLL 4147 9049 N 08816 2642 W 215207 00 A A 7F Copyright 2011 NavSync Ltd All Rights Reserved Specifications subject to change without notice 6 USER INTERFACE MESSAGES conti
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