Garmin GPS 35 LP, Technical Specification

Page 1: ...TM GPS SMART ANTENNA TECHNICAL SPECIFICATION Models GPS35 LVC GPS35 LVS GPS35 HVS ____________________________________________________________ GARMIN 1200 E 151st Street Olathe Kansas 66062 913 397 8200 913 397 8282 FAX ...

Page 2: ...nical including photocopying and recording for any purpose without the express written permission of GARMIN Information in this document is subject to change without notice GARMIN reserves the right to change or improve their products and to make changes in the content without obligation to notify any person or organization of such changes or improvements March 2000 190 00148 00 Rev E ...

Page 3: ... accept any interference received including interference that may cause undesired operation This device generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this device does cause har...

Page 4: ...igation 5 2 4 Satellite Data Collection 6 3 Hardware Interface 8 3 1 Mechanical Dimensions 8 3 2 Mounting Configurations and Options 9 3 3 Connection Wiring Description 13 4 Software Interface 14 4 1 NMEA Received Sentences 14 4 2 NMEA Transmitted Sentences 18 4 3 Baud Rate Selection 23 4 4 One Pulse Per Second Output 23 4 5 RTCM Received Data 23 A Earth Datums 24 B GPS 35LP Evaluation Kits 27 C P...

Page 5: ...OEM or system integrator A minimum system must provide the GPS 35LP with a source of power and a clear view of the GPS satellites The system may communicate with the GPS 35LP via a choice of two RS 232 compatible full duplex communication channels xVS series or two full duplex CMOS channels xVC series Internal memory backup allows the GPS 35LP to retain critical data such as satellite orbital para...

Page 6: ...otected if a high voltage is inadvertently applied to the input RS 232 Serial Data GPS35 xVS designation means that the two bi directional serial data ports are true RS 232 ports conforming to the RS 232E standard CMOS Serial Data GPS35 xVC designation means that the two bi directional serial data ports use CMOS output buffers The input buffers will accept either CMOS TTL voltage levels or RS 232 ...

Page 7: ... with Selective Availability on 5 Velocity accuracy 0 2 m s RMS steady state subject to Selective Availability 6 Dynamics 999 knots velocity 6g dynamics 7 One pulse per second accuracy 1 microsecond at rising edge of PPS pulse subject to Selective Availability 1 4 5 Interfaces 1 Dual channel CMOS TTL level xVC versions or RS 232 compatible level xVS versions with user selectable baud rate 300 600 ...

Page 8: ...4 4 One pulse per second timing output 5 Binary Format Phase Data 1 5 APPLICATION Fig 1 TYPICAL APPLICATION ARCHITECTURE ...

Page 9: ... position fix has been calculated valid position velocity and time information will be transmitted over the output channel s Like all GPS receivers the GPS 35LP utilizes initial data such as last stored position date and time as well as satellite orbital data to achieve maximum acquisition performance If significant inaccuracy exists in the initial data or if the orbital data is obsolete it may ta...

Page 10: ...GPS 35LP to choose differential only mode When navigating in the differential only mode the GPS 35LP will output a position only when a differential solution is available 2 4 SATELLITE DATA COLLECTION The GPS 35LP will automatically update satellite orbital data as it operates The intelligence of the GPS 35LP combined with its hardware capability allows these data to be collected and stored withou...

Page 11: ...7 minutes to calculate a navigation solution AutoLocate unlike search the sky does not require that the receiver continue to operate after a fix has been obtained ...

Page 12: ...RDWARE INTERFACE 3 1 MECHANICAL DIMENSIONS The GPS 35LP is a complete GPS receiver including antenna in a uniquely styled waterproof package 3 1 1 GPS 35 Dimensions General tolerance 0 50mm Fig 2 GPS 35LP Dimensions ...

Page 13: ...NS The following mounting options are available for the GPS 35LP Mounting is user configurable 3 2 1 Magnetic Mount The magnetic mount provides a firm removable mounting attachment to any ferrous metal surface Fig 3 Magnetic Mount Attachment ...

Page 14: ...10 3 2 2 Trunk Lip Mount The trunk lip mount provides a semi permanent attachment to the trunk lip of most automobiles Fig 4 Trunk Lip Mount Attachment ...

Page 15: ...11 3 2 3 Suction Cup Mount The suction cup bracket provides a removable mounting surface attached to the inside of a vehicle s windshield Fig 5 Suction Cup Mount Attachment ...

Page 16: ...unt The flange mount allows for a permanent installation on a flat surface This mounting configuration is ideal in applications in which the far side of the mounting surface is inaccessible Fig 6 Flange Mount Attachment ...

Page 17: ... input voltage range 25 V 25 This input may also be directly connected to standard 3 to 5Vdc CMOS logic The minimum low signal voltage requirement is 0 8V and the maximum high signal voltage requirement is 2 4V Maximum load impedance is 4 7K ohms This input may be used to receive serial initialization configuration data as specified in Section 4 1 Purple TXD2 Second Serial Asynchronous Output Elec...

Page 18: ... indicate no change in the particular configuration parameter All sentences received by the GPS 35LP must be terminated with CR LF but do not require the checksum hh The checksum is used for parity checking data and it is recommended that the checksum be used in environments containing high electromagnetic noise It is generally not required in normal PC environments Sentences may be truncated by C...

Page 19: ...urrent default values Current default values can also be obtained by sending PGRMCE to the board PGRMC 1 2 3 4 5 6 7 8 9 10 11 12 13 14 hh CR LF 1 Fix mode A automatic 2 2D exclusively host system must supply altitude 3 3D exclusively 2 Altitude above below mean sea level 1500 0 to 18000 0 meters 3 Earth datum index If the user datum index 96 is specified fields 4 through 8 must contain valid valu...

Page 20: ...guration changes take effect on the next power cycle or an external reset event At power up or external reset a stored beacon frequency other than 0 0 causes the GPS 35LP to tune the beacon receiver 4 1 5 Output Sentence Enable Disable PGRMO The PGRMO sentence provides the ability to enable and disable specific output sentences The following sentences are enabled at the factory GPGGA GPGSA GPGSV G...

Page 21: ...des the ability to tune a GARMIN GBR 21 or equivalent beacon receiver PSLIB 1 2 hh CR LF 1 Beacon tune frequency 0 0 283 5 325 0 kHz in 0 5 kHz steps 2 Beacon bit rate 0 25 50 100 or 200 bps If valid data is received the GPS 35LP will store it in the EEPROM and echo the PSLIB command to the beacon receiver At power up or external reset any stored frequency other than 0 0 causes the GPS 35LP to tun...

Page 22: ...board will transmit the selected sentences contiguously The contiguous transmission starts at a GPS second boundary The length of the transmission can be determined by the following equation and tables total characters to be transmitted length characters transmitted per sec Baud characters_transmitted_per_sec 300 30 600 60 1200 120 2400 240 4800 480 9600 960 19200 1920 Sentence max_characters GPGG...

Page 23: ...mitted this information for the leap second added December 31 1989 as follows Date Time 311289 235959 311289 235960 010190 000000 If a negative leap second should be required one second will be deleted at the end of some UTC month The minute containing the leap second will be only 59 seconds long In this case the GPS 35LP will not transmit the time of day 23h 59m 59s for the day from which the lea...

Page 24: ...ber of satellites in view 00 to 12 leading zeros will be transmitted 4 Satellite PRN number 01 to 32 leading zeros will be transmitted 5 Satellite elevation 00 to 90 degrees leading zeros will be transmitted 6 Satellite azimuth 000 to 359 degrees true leading zeros will be transmitted 7 Signal to noise ratio C No 00 to 99 dB null when not tracking leading zeros will be transmitted NOTE Items 4 5 6...

Page 25: ...hemisphere E or W 5 UTC time of position fix hhmmss format 6 Status A Valid position V NAV receiver warning 7 Mode indicator only output if NMEA 2 30 active A Autonomous D Differential E Estimated N Data not valid 4 2 10 Track Made Good and Ground Speed with LORAN Talker ID LCVTG The LCVTG sentence reports track and velocity information LCVTG 1 T 2 M 3 N 4 K 5 CR LF 1 True course over ground 000 t...

Page 26: ...elected baud rate PGRMT 1 2 3 4 5 6 7 8 9 hh CR LF 1 Product model and software version variable length field e g GPS 25LP VER 1 10 2 ROM checksum test P pass F fail 3 Receiver failure discrete P pass F fail 4 Stored data lost R retained L lost 5 Real time clock lost R retained L lost 6 Oscillator drift discrete P pass F excessive drift detected 7 Data collection discrete C collecting null if not ...

Page 27: ...le the GPS 35LP can compute a valid position fix To obtain the most accurate results the one pulse per second output should be calibrated against a local time reference to compensate for cable and internal receiver delays and the local time bias The default pulse width is 100 msec however it may be programmed is 20 msec increments between 20 msec and 980 msec as described in PGRMC Section 4 1 3 ch...

Page 28: ...ANTON ASTRO 1966 Phoenix Islands 18 CAPE CANAVERAL Florida Bahama Islands 19 CAPE South Africa 20 CARTHAGE Tunisia 21 CHATHAM 1971 Chatham Island New Zealand 22 CHUA ASTRO Paraguay 23 CORREGO ALEGRE Brazil 24 DJAKARTA BATAVIA Sumatra Island Indonesia 25 DOS 1968 Gizo Island New Georgia Islands 26 EASTER ISLAND 1967 Easter Island 27 EUROPEAN 1950 Austria Belgium Denmark Finland France Germany Gibra...

Page 29: ...MERICAN 1927 Greenland Hayes Peninsula 64 NORTH AMERICAN 1927 Mexico 65 NORTH AMERICAN 1927 San Salvador Island 66 NORTH AMERICAN 1983 Alaska Canada Central America CONUS Mexico 67 NAPARIMA BWI Trinidad and Tobago 68 NAHRWAN Masirah Island Oman 69 NAHRWAN Saudi Arabia 70 NAHRWAN United Arab Emirates 71 OBSERVATORIO 1966 Corvo and Flores Islands Azores 72 OLD EGYPTIAN Egypt 73 OLD HAWAIIAN Mean Val...

Page 30: ... Sabah 94 TOKYO Japan Korea Okinawa 95 TRISTAN ASTRO 1968 Tristan da Cunha 96 User defined earth datum 97 VITI LEVU 1916 Viti Levu Island Fiji Islands 98 WAKE ENIWETOK 1960 Marshall Islands 99 WORLD GEODETIC SYSTEM 1972 100 WORLD GEODETIC SYSTEM 1984 101 ZANDERIJ Surinam 102 CH 1903 Switzerland 103 Hu Tzu Shan 104 Indonesia 74 105 Austria 106 Potsdam 107 Taiwan modified Hu Tzu Shan ...

Page 31: ...ata in the sentence with the selected NMEA identifier highlighted in the top portion of the screen using the arrow keys The lower portion contains a formatted presentation of the currently selected sentence In addition to receiving data the program will also upload NMEA sentences to the sensor board The ALT U key sequence will upload the file NMEA TXT in the current directory to the unit Received ...

Page 32: ...ia RXD2 Download almanc and ephemeris information upon command GPS25PM EXE can be invoked from a DOS prompt path gps25pm exe com x b yyyy Where denotes user supplied information denotes optional parameters x is com port number 1 or 2 default is 1 yyyy is baud rate 1200 2400 4800 or 9600 default is 9600 See Appendix C for detailed description and operation of the GPS25PM EXE program ...

Page 33: ...aud rate to the same baud rate used for RTCM 104 data If the differential inputs are used on the GPS 35LP then the RTCM 104 data must be sent to the GPS 35LP at 9600 baud preferred or 4800 baud RTCM 104 baud rates less than 4800 baud are not supported by the GPS 35LP since it would limit bus bandwidth past the point where a once per second phase output data rate could be maintained Position Record...

Page 34: ...cycles double pr unsigned int phase char slp_dtct unsigned char snr_dbhz char svid char valid cpo_rcv_sv_type typedef struct double rcvr_tow int rcvr_wn cpo_rcv_sv_type sv 12 cpo_rcv_type rcvr_tow Receiver time of week sec rcvr_wn Receiver week number cycles Number of accumulated cycles pr pseudo range mt phase to convert to 0 359 999 multiply by 360 0 and divide by 2048 0 slp_dtct 0 no cycle slip...

Page 35: ...ue 256 int in_que_ptr 0 rx_state_type rx_state dat void add_to_que char data define dle_byte 0x10 define etx_byte 0x03 if rx_state dat if data dle_byte rx_state dle else in_que in_que_ptr data else if rx_state dle if data etx_byte rx_state etx else rx_state dat in_que in_que_ptr data else if rx_state etx if data dle_byte rx_state dle if in_que_ptr 255 in_que_ptr 0 ...

Page 36: ...tion updated at once a second A Position 1 WGS 84 Latitude Longitude degrees minutes 0 0001 minute resolution 2 Ellipsoid Altitude meters 1 meter resolution B Velocity 1 Each of 3 axis meters per second 0 01 m s resolution 2 Altitude meters minute 1 mt m resolution 3 Ground Speed kilometers hour 0 1 km h resolution C Estimated Position Error Vertical Horizontal Total meters 1 meter resolution D Tr...

Page 37: ...ition and Time Upload The program will prompt the user for the local time offset from UTC time This offset is then used to determine UTC time from the PC s real time clock The UTC time is then uploaded to the GPS25 sensor If an error occurs in the upload process a COMM ERROR will be enunciated on the screen After the UTC time has been uploaded the user is prompted for Latitude and Longitude for po...

Page 38: ...uploading to the GPS25 sensor EPHEMERS DAT Example ephemeris entry Week 794 Ephemeris for PRN 18 Ref Time of Clk Parms s 233504 000000 Ref Time of Eph Parms s 233504 000000 Clk Cor Group Dly s 8 280389E 006 Clk Correction af1 s s 3 410605E 013 Clk Correction af2 s s s 0 000000E 000 User Range Accuracy m 33 299999 Eccentricity 5 913425E 003 SQRT A m 1 2 5 153628E 003 Mean Motion Cor r s 4 710911E 0...

Page 39: ...city double sqrta square root of semi major axis a m 1 2 double dn mean motion correction r s double m0 mean anomaly at reference time r double w argument of perigee r double omg0 right ascension r double i0 inclination angle at reference time r float odot rate of right ascension r s float idot rate of inclination angle r s float cus argument of latitude correction sine r float cuc argument of lat...

Page 40: ...CV 18 50 T 76 6 19951681 26 2135704 RCV 29 50 T 284 4 20352180 11 2014308 RCV 28 45 T 320 8 21122272 68 2137669 RCV 19 47 T 8 3 21176671 33 2254110 RCV 31 45 T 170 2 21226528 82 2289074 RCV 22 42 T 315 9 22837584 50 1916778 RCV 27 36 T 132 4 24220207 85 2303835 RCV 14 39 T 127 4 25136106 23 1906158 PVT 235539 99999812 38 9499512 94 7463684 213 5 0 19 0 30 0 13 28 16 23 TIM 235540 99849199 794 RCV ...

Page 41: ...37 GARMIN Corporation 1200 East 151st Street Olathe KS 66062 913 397 8200 913 397 8282 FAX 190 00148 00 Rev E ...