Garmin Marine GPS System GP35 HVS User Manual

GPS 35 LP TracPak  
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  
 
CAUTION  
The GPS system is operated by the government of the United States which is solely responsible for its  
accuracy and maintenance. Although the GPS 35LP is a precision electronic NAVigation AID (NAVAID),  
any NAVAID can be misused or misinterpreted, and therefore become unsafe. Use the GPS 35LP at  
your own risk. To reduce the risk, carefully review and understand all aspects of this Technical Manual  
before using the GPS 35LP. When in actual use, carefully compare indications from the GPS 35LP to all  
available navigation sources including the information from other NAVAIDs, visual sightings, charts, etc.  
For safety, always resolve any discrepancies before continuing navigation.  
NOTE  
This device has been tested and found to comply with the limits for a Class B digital device, pursuant to  
Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not  
cause harmful interference, and (2) this device must 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  
harmful interference to radio or television reception, which can be determined by turning the device off  
and on, you are encouraged to try to correct the interference by one or more of the following measures:  
· Reorient or relocate the receiving antenna.  
· Increase the separation between this device and the receiver.  
· Connect this device to an outlet on a different circuit than that to which the receiver is connected.  
· Consult the dealer or an experienced radio/TV technician for help.  
This device contains no user-serviceable parts. Repairs should only be performed by an authorized  
GARMIN service center. Unauthorized repairs or modifications to this device could void your warranty  
and your authority to operate this device under Part 15 regulations.  
iii  
 
TABLE OF CONTENTS  
1.  
2.  
Introduction  
1
1
1
2
2
4
1.1  
1.2  
1.3  
1.4  
1.5  
Overview  
Features  
Naming Conventions  
Technical Specifications  
Application  
Operational Characteristics  
5
5
5
5
6
2.1  
2.2  
2.3  
2.4  
Self Test  
Initialization  
Navigation  
Satellite Data Collection  
3.  
4.  
Hardware Interface  
8
8
9
3.1  
3.2  
3.3  
Mechanical Dimensions  
Mounting Configurations and Options  
Connection Wiring Description  
13  
Software Interface  
14  
14  
18  
23  
23  
23  
4.1  
4.2  
4.3  
4.4  
4.5  
NMEA Received Sentences  
NMEA Transmitted Sentences  
Baud Rate Selection  
One-Pulse-Per-Second Output  
RTCM Received Data  
A.  
B.  
C.  
Earth Datums  
GPS 35LP Evaluation Kits  
Phase Data Output  
24  
27  
29  
iv  
 
SECTION 1  
INTRODUCTION  
1.1 OVERVIEW  
The GARMIN GPS 35LP is a complete GPS receiver, including an embedded antenna, designed for a  
broad spectrum of OEM (Original Equipment Manufacturer) system applications. Based on the proven  
technology found in other GARMIN 12 channel GPS receivers, the GPS 35LP will track up to 12  
satellites at a time while providing fast time-to-first-fix, one second navigation updates and low power  
consumption. Its far reaching capability meets the sensitivity requirements of land navigation as well as  
the dynamics requirements of high performance aircraft.  
The GPS 35LP design utilizes the latest technology and high level circuit integration to achieve superior  
performance while minimizing space and power requirements. All critical components of the system  
including the RF/IF receiver hardware and the digital baseband are designed and manufactured by  
GARMIN to ensure the quality and capability of the GPS 35LP. This hardware capability combined with  
software intelligence makes the GPS 35LP easy to integrate and use.  
The GPS 35LP is designed to withstand rugged operating conditions and is completely water resistant.  
The GPS 35LP is a complete GPS receiver that requires minimal additional components be supplied by  
an 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 parameters, last position, date and time. End user interfaces such as keyboards and  
displays are added by the application designer.  
1.2  
FEATURES  
The GPS 35LP provides a host of features that make it easy to integrate and use.  
1) Full navigation accuracy provided by Standard Positioning Service (SPS)  
2) Compact design ideal for applications with minimal space  
3) High performance receiver tracks up to 12 satellites while providing fast first fix and low power  
consumption  
4) Differential capability utilizes real-time RTCM corrections producing 3-10 meter position accuracy  
5) Internal clock and memory are sustained by a rechargeable memory backup battery. The battery  
recharges during normal operation.  
6) User initialization is not required  
7) Navigation mode (2D or 3D) may be configured by the user  
8) Two communication channels and user selectable baud rates allow maximum interface capability  
and flexibility  
9) Highly accurate one-pulse-per-second output for precise timing measurements. Pulse width is  
configurable in 20 msec increments from 20 msec to 980 msec.  
1
 
10) Binary Format Phase Data Output on TXD2  
11) Flexible input voltage levels of 3.6Vdc to 6.0Vdc with overvoltage protection in the -LVx versions,  
and 6.0Vdc to 40Vdc in the -HVx versions.  
12) FLASH based program memory. New software revisions upgradeable through serial interface.  
1.3 Naming Conventions  
The GPS 35LP Series TrackPack™ receivers are delineated with a three letter extension to designate  
the operating voltage range and the serial data voltage specification.  
High Voltage - GPS35-HVx designation indicates that the unit will accept a high input voltage. The  
internal switching regulator will operate from a 6VDC to 40VDC unregulated supply.  
Low Voltage - GPS35-LVx designation indicates that the unit is designed to operated from a low  
voltage 3.6VDC to 6.0VDC supply. Operation at about 4VDC is the most power efficient mode of  
operation for the GPS35LP receiver. The unit is protected 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 voltage levels. This configuration is adequate for communicating directly with serial devices  
over short cable lengths (less than 20 meters).  
1.4 TECHNICAL SPECIFICATIONS  
Specifications are subject to change without notice.  
1.4.1  
Physical Characteristics  
1) Single construction integrated antenna/receiver.  
2) Weight: 4.4 oz, (124.5 g), not including cable  
3) Size: 2.230" (w) x 3.796" (l) x 1.047" (h), (56.64 mm x 96.42 mm x 26.60 mm)  
1.4.2  
Environmental Characteristics  
1) Operating temperature: -30°C to +85°C (internal temperature)  
2) Storage temperature: -40°C to +90°C  
1.4.3 Electrical Characteristics  
1) Input voltage: +3.6VDC to 6.0VDC regulated, 150mV ripple -LVx versions.  
+6.0VDC to 40VDC unregulated -HVx version.  
2
 
2) Input current: 120 mA typical 140 mA max -LVx versions, 20 mA while in power down.  
870mW typical 1000mW max -HVx version, 300uA while in power down.  
3) Backup power: 3V Rechargeable Lithium cell battery, up to 6 month charge.  
4) Power Down Input: 2.7V threshold  
1.4.4 Performance  
1) Tracks up to 12 satellites (up to 11 with PPS active)  
2) Update rate: 1 second  
3) Acquisition time  
- 15 seconds warm (all data known)  
- 45 seconds cold (initial position, time and  
almanac known, ephemeris unknown)  
- 5.0 minutes AutoLocate TM (almanac known,  
initial position and time unknown)  
- 5 minutes search the sky (no data known)  
4) Position accuracy:  
Differential GPS (DGPS): 5 meters RMS  
Non-differential GPS: 15 meters RMS (100 meters 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, 600,1200, 2400, 4800, 9600, 19200)  
2) NMEA 0183 Version 2.0 ASCII output (GPALM, GPGGA, GPGSA, GPGSV, GPRMC, GPVTG,  
PGRME, PGRMT, PGRMV, PGRMF, LCGLL, LCVTG)  
Inputs  
- Initial position, date and time (not required)  
- Earth datum and differential mode configuration command, PPS Enable, almanac  
Outputs  
- Position, velocity and time  
- Receiver and satellite status  
- Differential Reference Station ID and RTCM Data age  
- Geometry and error estimates  
3) Real-time Differential Correction input (RTCM SC-104 message types 1,2,3 and 9)  
3
 
4) One-pulse-per-second timing output  
5) Binary Format Phase Data  
1.5 APPLICATION  
Fig. 1, TYPICAL APPLICATION ARCHITECTURE  
4
 
SECTION 2  
OPERATIONAL CHARACTERISTICS  
This section describes the basic operational characteristics of the GPS 35LP. Additional information  
regarding input and output specifications are contained in Section 4.  
2.1 SELF TEST  
After input power has been applied to the GPS 35LP and periodically thereafter, the unit will perform  
critical self test functions and report the results over the output channel(s). The following tests will be  
performed:  
1) RAM check  
2) FLASH memory test  
3) Receiver test  
4) Real-time clock test  
5) Oscillator check  
In addition to the results of the above tests, the GPS 35LP will report software version information.  
2.2 INITIALIZATION  
After the initial self test is complete, the GPS 35LP will begin the process of satellite acquisition and  
tracking. The acquisition process is fully automatic and, under normal circumstances, will take  
approximately 45 seconds to achieve a position fix (15 seconds if ephemeris data is known). After a  
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 take 5.0 minutes to achieve a navigation  
solution. The GPS 35LP AutolocateTM feature is capable of automatically determining a navigation  
solution without intervention from the host system. However, acquisition performance can be improved if  
the host system initializes the GPS 35LP following the occurrence of one or more of the following events:  
1) Transportation over distances further than 1500 kilometers  
2) Failure of the internal memory battery without system standby power  
3) Stored date/time off by more than 30 minutes  
See Section 4 for more information on initializing the GPS 35LP.  
2.3 NAVIGATION  
After the acquisition process is complete, the GPS 35LP will begin sending valid navigation information  
over its output channels. These data include:  
5
 
1) Latitude/longitude/altitude  
2) Velocity  
3) Date/time  
4) Error estimates  
5) Satellite and receiver status  
Normally the GPS 35LP will select the optimal navigation mode (2D or 3D) based on available satellites  
and geometry considerations. The host system, at its option, may command the GPS 35LP to choose a  
specific mode of navigation, such as 2D. The following modes are available:  
1) 2D exclusively with altitude supplied by the host system (altitude hold mode)  
2) 3D exclusively with altitude computed by the GPS 35LP  
3) Automatic mode in which the board set determines the desired mode based on satellite availability  
and geometry considerations  
When navigating in the 2D mode (either exclusive or automatic), the GPS 35LP utilizes the last  
computed altitude or the last altitude supplied by the host system, whichever is newer. The host system  
must ensure that the altitude used for 2D navigation is accurate since the resulting position error may be  
as large as the altitude error. See Section 4 for more information on altitude control.  
The GPS 35LP will default to automatic differential mode – “looking” for real-time differential corrections  
in RTCM SC-104 standard format, with message types 1,2,3, or 9, then attempt to apply them to the  
satellite data, in order to produce a differential (DGPS) solution. The host system, at its option, may also  
command the 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 without  
intervention from the host system. A few key points should be considered regarding this process:  
1) If the receiver is not operated for a period of six (6) months or more, the unit will “search the sky”  
in order to collect satellite orbital information. This process is fully automatic and, under normal  
circumstances, will take 3-4 minutes to achieve a navigation solution. However, the host system  
should allow the board set to remain on for at least 12.5 minutes after the first satellite is acquired  
(see Section 4 for more information on status indications).  
2) If the memory backup battery fails, the receiver will search the sky as described above. Should  
the memory battery discharge, the unit needs to be powered on for several days to insure a  
sufficient recharge to maintain several months of clock operation and memory storage. System  
configuration information will not be lost due to battery discharge, only previous position, time and  
almanac data will be lost.  
3) If the initial data is significantly inaccurate, the receiver perform an operation known as  
AutoLocate . This procedure is fully automatic and, under normal circumstances, will require 1.5  
6
 
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.  
7
 
SECTION 3  
HARDWARE 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  
8
 
3.2 MOUNTING CONFIGURATIONS AND OPTIONS  
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  
9
 
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  
10  
 
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  
11  
 
3.2.4 Flange Mount  
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  
12  
 
3.3 CONNECTION WIRING DESCRIPTION  
The GPS 35LP features a stripped and pre-tinned cable assembly for connection flexibility. The following  
is a functional description of each wire in the cable assembly.  
Red: Vin - Regulated +3.6V to +6V, 150 mA (maximum) in the -LVx versions. Typical operating  
current is 120 mA. Transients and overvoltages are protected by an internal 6.8V transient  
zener diode and a positive temperature coefficient thermistor. With voltages greater than  
6.8Vdc the zener will draw several amps of current through the thermistor, causing it to heat  
rapidly and eventually power the unit off, unless an external fuse blows first. When proper  
supply voltages are returned, the thermistor will cool and allow the GPS 35-LVx to operate.  
The CMOS/TTL output buffers are powered by Vin, therefore a 3.6Vdc supply will create  
3.6V logic output levels.  
In the -HVx versions, Vin can be an unregulated 6.0Vdc to 40Vdc, optimized for 12Vdc.  
Typical operating power is 800mW This voltage drives a switching regulator with a nominal  
4.4Vdc output, which powers the internal linear regulators, and the CMOS output buffers.  
Black: GND - Power and Signal Ground  
White: TXD1 - First Serial Asynchronous Output. CMOS/TTL output levels vary between 0V and  
Vin in the -LVC version. In the -LVS and -HVS versions a RS-232 compatible output driver  
is available. This output normally provides serial data which is formatted per “NMEA 0183,  
Version 2.0”. Switchable to 300, 600, 1200, 2400, 4800, 9600 or 19200 BAUD. The default  
BAUD is 4800.  
Blue: RXD1 - First Serial Asynchronous Input. RS-232 compatible with maximum 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. Electrically identical to TXD1. This output  
provides phase data information for software version 2.03 or above. See Appendix C for  
details.  
Green: RXD2 - Second Serial Asynchronous Input. Electrically identical to RXD1. This input may  
be used to receive serial differential GPS data formatted per “RTCM Recommended  
Standards For Differential Navstar GPS Service, Version 2.1” (see Section 4 for more  
details).  
Gray: PPS - One-Pulse-Per-Second Output. Typical voltage rise and fall times are 300 nSec.  
Impedance is 250 ohms. Open circuit output voltage is 0V and Vin in the -LVx versions,  
and 0V and 4.4V in the -HVx. The default format is a 100 millisecond high pulse at a 1Hz  
rate, the pulse width is programmable from a configuration command in 20msec  
increments. Rising edge is synchronized to the start of each GPS second. This output will  
provide a nominal 700 mVp-p signal into a 50 Ohm load. The pulse time measured at the  
50% voltage point will be about 50 nSec earlier with a 50 Ohm load than with no load.  
Yellow: POWER DOWN - External Power Down Input. Inactive if not connected or less than 0.5V.  
Active if greater than 2.7V. Typical switch point is 2.0V @ 0.34 mA. Input impedance is  
15K Ohms.  
Activation of this input powers the internal regulators off and drops the  
supply current below 20mA in the -LVx versions, and below 1mA in the -HVx. The  
computer will be reset when power is restored.  
Section 4  
13  
 
Software Interface  
The GPS 35LP interface protocol design is based on the National Marine Electronics Association’s  
NMEA 0183 ASCII interface specification, which is fully defined in “NMEA 0183, Version 2.0” (copies  
may be obtained from NMEA, P.O. Box 50040, Mobile, AL, 36605, USA) and the Radio Technical  
Commission for Maritime Services’ “RTCM Recommended Standards For Differential Navstar GPS  
Service, Version 2.1, RTCM Special Committee No. 104” (copies may be obtained from RTCM, P.O. Box  
19087, Washington, DC, 20036, USA). The GPS 35LP interface protocol, in addition to transmitting  
navigation information as defined by NMEA 0183, transmits additional information using the convention  
of GARMIN proprietary sentences.  
The following sections describe the data format of each sentence transmitted and received by the GPS  
35LP sensor. The baud rate selection, one-pulse-per-second output interfaces and RTCM differential  
GPS input are also described.  
4.1 NMEA Received sentences  
The subsequent paragraphs define the sentences which can be received on RXD1 by the GPS 35LP  
receivers. Null fields in the configuration sentence 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 <CR><LF> after any data field and valid fields up to that  
point will be acted on by the GPS 35LP.  
4.1.1  
Almanac Information (ALM)  
$GPALM,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15> *hh<CR><LF>  
The $GPALM sentence can be used to initialize the receivers stored almanac information if battery back-  
up has failed.  
<1>  
<2>  
Total number of ALM sentences to be transmitted by the sensor board during almanac download.  
This field can be null or any number when sending almanac to the sensor board.  
Number of current ALM sentence. This field can be null or any number when sending almanac  
to the sensor board.  
<3>  
<4>  
<5>  
<6>  
<7>  
<8>  
<9>  
Satellite PRN number, 01 to 32.  
GPS week number.  
SV health, bits 17-24 of each almanac page.  
Eccentricity  
Almanac reference time.  
Inclination angle.  
Rate of right ascension.  
<10> Root of semi major axis.  
<11> Omega, argument of perigee.  
<12> Longitude of ascension node.  
<13> Mean anomaly  
<14> afo clock parameter  
<15> af1 clock parameter  
14  
 
4.1.2  
Sensor Initialization Information (PGRMI)  
The $PGRMI sentence provides information used to initialize the sensor board set position and time  
used for satellite acquisition. Receipt of this sentence by the board set causes the software to restart the  
satellite acquisition process. If there are no errors in the sentence, it will be echoed upon receipt. If an  
error is detected, the echoed PGRMI sentence will contain the current default values. Current PGRMI  
defaults can also be obtained by sending $PGRMIE to the board.  
$PGRMI,<1>,<2>,<3>,<4>,<5>,<6>,<7>*hh<CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
<6>  
<7>  
Latitude, ddmm.mmm format (leading zeros must be transmitted)  
Latitude hemisphere, N or S  
Longitude, dddmm.mmm format (leading zeros must be transmitted)  
Longitude hemisphere, E or W  
Current UTC date, ddmmyy format  
Current UTC time, hhmmss format  
Receiver Command, A = Auto Locate, R = Unit Reset.  
4.1.3  
Sensor Configuration Information (PGRMC)  
The $PGRMC sentence provides information used to configure the sensor board operation.  
Configuration parameters are stored in non-volatile memory and retained between power cycles. The  
GPS 35LP will echo this sentence upon its receipt if no errors are detected. If an error is detected, the  
echoed PGRMC sentence will contain the current 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>  
<3>  
Altitude above/below mean sea level, -1500.0 to 18000.0 meters  
Earth datum index. If the user datum index (96) is specified, fields <4> through <8> must  
contain valid values. Otherwise, fields <4> through <8> must be null. Refer to Appendix A for a  
list of earth datums and the corresponding earth datum index.  
<4>  
User earth datum semi-major axis, 6360000.0 to 6380000.0 meters (.001 meters resolution)  
-9  
<5>  
<6>  
User earth datum inverse flattening factor, 285.0 to 310.0 (10 resolution)  
User earth datum delta x earth centered coordinate, -5000.0 to 5000.0 meters (1 meter  
resolution)  
<7>  
<8>  
<9>  
User earth datum delta y earth centered coordinate, -5000.0 to 5000.0 meters (1 meter  
resolution)  
User earth datum delta z earth centered coordinate, -5000.0 to 5000.0 meters (1 meter  
resolution)  
Differential mode, A = automatic (output DGPS data when available, non-DGPS otherwise), D =  
differential exclusively (output only differential fixes)  
<10> NMEA Baud rate, 1 = 1200, 2 = 2400, 3 = 4800, 4 = 9600, 5 = 19200, 6 = 300, 7 = 600  
<11> Velocity filter, 0 = No filter, 1 = Automatic filter, 2-255 = Filter time constant (10 = 10 second  
filter  
<12> PPS mode, 1 = No PPS, 2 = 1 Hz  
<13> PPS pulse length, 0-48 = (n+1)*20msec. Example n = 4 ð 100 msec pulse  
<14> Dead reckoning valid time 1-30 (sec)  
15  
 
All configuration changes take effect after receipt of a valid value except baud rate and PPS mode.  
Baud rate and PPS mode changes take effect on the next power cycle or an external reset event.  
4.1.4 Additional Sensor Configuration Information (PGRMC1)  
The $PGRMC1 sentence provides additional information used to configure the sensor board operation.  
Configuration parameters are stored in non-volatile memory and retained between power cycles. The  
GPS 35LP will echo this sentence upon its receipt if no errors are detected. If an error is detected, the  
echoed PGRMC1 sentence will contain the current default values. Current default values can also be  
obtained by sending $PGRMC1E to the board.  
$PGRMC1,<1>,<2>,<3>,<4>,<5>,<6>,<7>*hh<CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
<6>  
<7>  
NMEA output time 1-900 (sec).  
Binary Phase Output Data, 1 = Off, 2 = On.  
Position pinning, 1 = Off, 2 = On.  
DGPS beacon frequency – 0.0, 283.5 – 325.0 kHz in 0.5 kHz steps.  
DGPS beacon bit rate – 0, 25, 50, 100, or 200 bps.  
DGPS beacon auto tune on station loss, 1 = Off, 2 = On.  
Activate NMEA 2.30 mode indicator, 1 = Off, 2 = On.  
Configuration 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, GPRMC, and PGRMT.  
$PGRMO,<1>,<2>*hh<CR><LF>  
<1>  
<2>  
Target sentence description (e.g., PGRMT, GPGSV, etc.)  
Target sentence mode, where:  
0 = disable specified sentence  
1 = enable specified sentence  
2 = disable all output sentences  
3 = enable all output sentences (except GPALM)  
The following notes apply to the PGRMO input sentence:  
1) If the target sentence mode is ‘2’ (disable all) or ‘3’ (enable all), the target sentence description is  
not checked for validity. In this case, an empty field is allowed (e.g., $PGRMO,,3), or the mode  
field may contain from 1 to 5 characters.  
2) If the target sentence mode is ‘0’ (disable) or ‘1’ (enable), the target sentence description field must  
be an identifier for one of the sentences being output by the GPS 25LP.  
3) If either the target sentence mode field or the target sentence description field is not valid, the  
PGRMO sentence will have no effect.  
16  
 
4) $PGRMO,GPALM,1 will cause the sensor board to transmit all stored almanac information. All  
other NMEA sentence transmission will be temporarily suspended.  
4.1.6 Tune DGPS Beacon Receiver (PSLIB)  
The $PSLIB sentence provides the ability to tune a GARMIN GBR-21 or equivalent beacon receiver.  
$PSLIB,<1>,<2>*hh<CR><LF>  
<1>  
<2>  
Beacon tune frequency, 0.0, 283.5 – 325.0 kHz in 0.5 kHz steps  
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 tune the beacon receiver.  
17  
 
4.2 NMEA Transmitted Sentences  
The subsequent paragraphs define the sentences which can be transmitted on TXD1 by the GPS 35LP  
receivers.  
4.2.1  
Sentence Transmission Rate  
Sentences are transmitted with respect to the user selected baud rate.  
Regardless of the selected baud rate, the information transmitted by the GPS 35LP is referenced to the  
one-pulse-per-second output pulse immediately preceding the GPRMC sentence.  
The GPS 35LP will transmit each sentence (except where noted in particular transmitted sentence  
descriptions) at a periodic rate based on the user selected baud rate and user selected output sentences.  
The sensor 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  
300  
600  
characters_transmitted_per_sec  
30  
60  
1200  
2400  
4800  
9600  
19200  
120  
240  
480  
960  
1920  
Sentence  
GPGGA  
GPGSA  
GPGSV  
GPRMC  
GPVTG  
PGRMB  
PGRME  
PGRMT  
PGRMV  
PGRMF  
LCGLL  
max_characters  
81  
66  
210  
74  
42  
26  
35  
50  
32  
82  
44  
39  
LCVTG  
The maximum number of fields allowed in a single sentence is 82 characters including delimiters.  
Values in the table include the sentence start delimiter character “$” and the termination delimiter  
<CR><LF>.  
The factory set defaults will result in a once per second transmission at the NMEA specification  
transmission rate of 4800 baud.  
18  
 
4.2.2 Transmitted Time  
The GPS 35LP receivers output UTC (Coordinated Universal Time) date and time of day in the  
transmitted sentences. Prior to the initial position fix, the date and time of day are provided by the on-  
board clock. After the initial position fix, the date and time of day are calculated using GPS satellite  
information and are synchronized with the one-pulse-per-second output.  
The GPS 35LP uses information obtained from the GPS satellites to add or delete UTC leap seconds  
and correct the transmitted date and time of day. The transmitted date and time of day for leap second  
correction follow the guidelines in “National Institute of Standards and Technology Special Publication  
432 (Revised 1990)” (for sale by the Superintendent of Documents, U.S. Government Printing Office,  
Washington, DC, 20402, USA).  
When a positive leap second is required, the second is inserted beginning at 23h 59m 60s of the last day  
of a month and ending at 0h 0m 0s of the first day of the following month. The minute containing the  
leap second is 61 seconds long. The GPS 35LP would have transmitted this information for the leap  
second added December 31, 1989 as follows:  
Date  
Time  
311289  
311289  
010190  
235959  
235960  
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 leap second is removed.  
4.2.3 Global Positioning System Almanac Data (ALM)  
<field information> can be found in section 4.1.1.  
$GPALM,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>*hh<CR><LF>  
Almanac sentences are not normally transmitted. Almanac transmission can be initiated by sending the  
sensor board a $PGRMO,GPALM,1 command. Upon receipt of this command the sensor board will  
transmit available almanac information on GPALM sentences. During the transmission of almanac  
sentences other NMEA data output will be temporarily suspended.  
<field information> can be found in section 4.1.1.  
4.2.4  
Global Positioning System Fix Data (GGA)  
$GPGGA,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,M,<10>,M,<11>,<12>*hh<CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
UTC time of position fix, hhmmss format  
Latitude, ddmm.mmmm format (leading zeros will be transmitted)  
Latitude hemisphere, N or S  
Longitude, dddmm.mmmm format (leading zeros will be transmitted)  
Longitude hemisphere, E or W  
19  
 
<6>  
GPS quality indication,  
0 = fix not available,  
1 = Non-differential GPS fix available,  
2 = Differential GPS (DGPS) fix available  
6 = Estimated  
<7>  
<8>  
<9>  
Number of satellites in use, 00 to 12 (leading zeros will be transmitted)  
Horizontal dilution of precision, 0.5 to 99.9  
Antenna height above/below mean sea level, -9999.9 to 99999.9 meters  
<10> Geoidal height, -999.9 to 9999.9 meters  
<11> Differential GPS (RTCM SC-104) data age, number of seconds since last valid RTCM  
transmission (null if non-DGPS)  
<12> Differential Reference Station ID, 0000 to 1023 (leading zeros transmitted, null if non-DGPS)  
4.2.5  
GPS DOP and Active Satellites (GSA)  
$GPGSA,<1>,<2>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<4>,<5>,<6>*hh<CR><LF>  
<1>  
<2>  
<3>  
Mode, M = manual, A = automatic  
Fix type, 1 = not available, 2 = 2D, 3 = 3D  
PRN number, 01 to 32, of satellite used in solution, up to 12 transmitted (leading zeros will be  
transmitted)  
<4>  
<5>  
<6>  
Position dilution of precision, 0.5 to 99.9  
Horizontal dilution of precision, 0.5 to 99.9  
Vertical dilution of precision, 0.5 to 99.9  
4.2.6  
GPS Satellites in View (GSV)  
$GPGSV,<1>,<2>,<3>,<4>,<5>,<6>,<7>,...<4>,<5>,<6>,<7>*hh<CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
<6>  
<7>  
Total number of GSV sentences to be transmitted  
Number of current GSV sentence  
Total number of satellites in view, 00 to 12 (leading zeros will be transmitted)  
Satellite PRN number, 01 to 32 (leading zeros will be transmitted)  
Satellite elevation, 00 to 90 degrees (leading zeros will be transmitted)  
Satellite azimuth, 000 to 359 degrees, true (leading zeros will be transmitted)  
Signal to noise ratio (C/No) 00 to 99 dB, null when not tracking (leading zeros will be transmitted)  
NOTE: Items <4>,<5>,<6> and <7> repeat for each satellite in view to a maximum of four (4) satellites  
per sentence. Additional satellites in view information must be sent in subsequent sentences.  
These fields will be null if unused.  
4.2.7 Recommended Minimum Specific GPS/TRANSIT Data (RMC)  
$GPRMC,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>*hh<CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
<6>  
<7>  
<8>  
<9>  
UTC time of position fix, hhmmss format  
Status, A = Valid position, V = NAV receiver warning  
Latitude, ddmm.mmmm format (leading zeros will be transmitted)  
Latitude hemisphere, N or S  
Longitude, dddmm.mmmm format (leading zeros will be transmitted)  
Longitude hemisphere, E or W  
Speed over ground, 0000.0 to 1851.8 knots (leading zeros will be transmitted)  
Course over ground, 000.0 to 359.9 degrees, true (leading zeros will be transmitted)  
UTC date of position fix, ddmmyy format  
<10> Magnetic variation, 000.0 to 180.0 degrees (leading zeros will be transmitted)  
<11> Magnetic variation direction, E or W (westerly variation adds to true course)  
20  
 
<12> Mode indicator (only output if NMEA 2.30 active), A = Autonomous, D = Differential, E =  
Estimated, N = Data not valid  
4.2.8 Track Made Good and Ground Speed with GPS Talker ID (VTG)  
The GPVTG sentence reports track and velocity information with a checksum:  
$GPVTG,<1>,T,<2>,M,<3>,N,<4>,K,<5>*hh<CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
True course over ground, 000 to 359 degrees (leading zeros will be transmitted)  
Magnetic course over ground, 000 to 359 degrees (leading zeros will be transmitted)  
Speed over ground, 000.0 to 999.9 knots (leading zeros will be transmitted)  
Speed over ground, 0000.0 to 1851.8 kilometers per hour (leading zeros will be transmitted)  
Mode indicator (only output if NMEA 2.30 active), A = Autonomous, D = Differential, E =  
Estimated, N = Data not valid  
4.2.9 Geographic Position with LORAN Talker ID (LCGLL)  
The LCGLL sentence reports position information.  
$LCGLL,<1>,<2>,<3>,<4>,<5>,<6>,<7><CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
<6>  
<7>  
Latitude, ddmm.mmmm format (leading zeros will be transmitted)  
Latitude hemisphere, N or S  
Longitude, dddmm.mmmm format (leading zeros will be transmitted)  
Longitude hemisphere, E or W  
UTC time of position fix, hhmmss format  
Status, A = Valid position, V = NAV receiver warning  
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>  
<2>  
<3>  
<4>  
<5>  
True course over ground, 000 to 359 degrees (leading zeros will be transmitted)  
Magnetic course over ground, 000 to 359 degrees (leading zeros will be transmitted)  
Speed over ground, 000.0 to 999.9 knots (leading zeros will be transmitted)  
Speed over ground, 0000.0 to 1851.8 kilometers per hour (leading zeros will be transmitted)  
Mode indicator (only output if NMEA 2.30 active), A = Autonomous, D = Differential, E =  
Estimated, N = Data not valid  
4.2.11  
Estimated Error Information (PGRME)  
The GARMIN Proprietary sentence $PGRME reports estimated position error information.  
$PGRME,<1>,M,<2>,M,<3>,M*hh<CR><LF>  
<1>  
<2>  
<3>  
Estimated horizontal position error (HPE), 0.0 to 999.9 meters  
Estimated vertical position error (VPE), 0.0 to 999.9 meters  
Estimated position error (EPE), 0.0 to 999.9 meters  
4.2.12  
GPS Fix Data Sentence (PGRMF)  
The sentence $PGRMF is GARMIN Proprietary format.  
21  
 
$PGRMF,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>*hh<CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
<6>  
<7>  
<8>  
<9>  
GPS week number (0 - 1023)  
GPS seconds (0 - 604799)  
UTC date of position fix, ddmmyy format  
UTC time of position fix, hhmmss format  
GPS leap second count  
Latitude, ddmm.mmmm format (leading zeros will be transmitted)  
Latitude hemisphere, N or S  
Longitude, dddmm.mmmm format (leading zeros will be transmitted)  
Longitude hemisphere, E or W  
<10> Mode, M = manual, A = automatic  
<11> Fix type, 0 = no fix, 1 = 2D fix, 2 = 3D fix  
<12> Speed over ground, 0 to 1851 kilometers/hour  
<13> Course over ground, 0 to 359 degrees, true  
<14> Position dilution of precision, 0 to 9 (rounded to nearest integer value)  
<15> Time dilution of precision, 0 to 9 (rounded to nearest integer value)  
4.2.13  
Sensor Status Information (PGRMT)  
The GARMIN Proprietary sentence $PGRMT gives information concerning the status of the sensor  
board. This sentence is transmitted once per minute regardless of the selected baud rate.  
$PGRMT,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>*hh<CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
<6>  
<7>  
<8>  
<9>  
Product, model and software version (variable length field, e.g., “GPS 25LP VER 1.10”)  
ROM checksum test, P = pass, F = fail  
Receiver failure discrete, P = pass, F = fail  
Stored data lost, R = retained, L = lost  
Real time clock lost, R = retained, L = lost  
Oscillator drift discrete, P = pass, F = excessive drift detected  
Data collection discrete, C = collecting, null if not collecting  
Board temperature in degrees C  
Board configuration data, R = retained, L = lost  
4.2.14  
3D velocity Information (PGRMV)  
The GARMIN Proprietary sentence $PGRMV reports three-dimensional velocity information.  
$PGRMV,<1>,<2>,<3>*hh<CR><LF>  
<1>  
<2>  
<3>  
True east velocity, -514.4 to 514.4 m/second  
True north velocity, -514.4 to 514.4 m/second  
Up velocity, -999.9 to 9999.9 m/second  
4.2.15  
DGPS Beacon Information (PGRMB)  
The GARMIN proprietary sentence $PGRMB reports DGPS beacon information.  
$PGRMB,<1>,<2>,<3>,<4>,<5>,K*<CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
Beacon tune frequency, 0.0, 283.5 – 325.0 kHz in 0.5 kHz steps  
Beacon bit rate, 0, 25, 50, 100, or 200 bps  
Beacon SNR, 0 to 31  
Beacon data quality, 0 to 100  
Distance to beacon reference station in kilometers  
22  
 
4.3 Baud Rate Selection  
Baud rate selection can be performed by sending the appropriate configuration sentence to the sensor  
board as described in the NMEA input sentences selection. (Section 4.1)  
4.4 One-Pulse-Per-Second Output  
The highly accurate one-pulse-per-second output is provided for applications requiring precise timing  
measurements. The signal is generated after the initial position fix has been calculated and continues  
until power down. The rising edge of the signal is synchronized to the start of each GPS second.  
Regardless of the selected baud rate, the information transmitted by the GPS 35LP receiver is  
referenced to the pulse immediately preceding the NMEA 0183 RMC sentence.  
The accuracy of the one-pulse-per-second output is maintained only while 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 character <13>.  
4.5 RTCM Received Data  
Position accuracy of less than 5 meters can be achieved with the GPS 35LP by using Differential GPS  
(DGPS) real-time pseudo-range correction data in RTCM SC-104 format, with message types 1, 2, 3,  
and 9. These corrections can be received by the GPS 35LP receiver on RXD2. Correction data at  
speeds of 300, 600, 1200, 2400, 4800 or 9600 baud can be utilized, as the GPS 35LP automatically  
detects the incoming baud rate. For details on the SC-104 format, refer to RTCM Paper 134-89/SC 104-  
68 by the Radio Technical Commission for Maritime Services.  
23  
 
Appendix A  
Earth Datums  
The following is a list of the GARMIN GPS 35LP earth datum indexes and the corresponding earth  
datum name (including the area of application):  
0
1
ADINDAN - Ethiopia, Mali, Senegal, Sudan  
AFGOOYE - Somalia  
2
3
AIN EL ABD 1970 - Bahrain Island, Saudi Arabia  
ANNA 1 ASTRO 1965 - Cocos Island  
4
5
ARC 1950 - Botswana, Lesotho, Malawi, Swaziland, Zaire, Zambia, Zimbabwe  
ARC 1960 - Kenya, Tanzania  
6
7
ASCENSION ISLAND 1958 - Ascension Island  
ASTRO BEACON “E” - Iwo Jima Island  
8
9
AUSTRALIAN GEODETIC 1966 - Australia, Tasmania Island  
AUSTRALIAN GEODETIC 1984 - Australia, Tasmania Island  
ASTRO DOS 71/4 - St. Helena Island  
ASTRONOMIC STATION 1952 - Marcus Island  
ASTRO B4 SOROL ATOLL - Tern Island  
BELLEVUE (IGN) - Efate and Erromango Islands  
BERMUDA 1957 - Bermuda Islands  
BOGOTA OBSERVATORY - Colombia  
CAMPO INCHAUSPE - Argentina  
CANTON ASTRO 1966 - Phoenix Islands  
CAPE CANAVERAL - Florida, Bahama Islands  
CAPE - South Africa  
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
26  
27  
CARTHAGE - Tunisia  
CHATHAM 1971 - Chatham Island (New Zealand)  
CHUA ASTRO - Paraguay  
CORREGO ALEGRE - Brazil  
DJAKARTA (BATAVIA) - Sumatra Island (Indonesia)  
DOS 1968 - Gizo Island (New Georgia Islands)  
EASTER ISLAND 1967 - Easter Island  
EUROPEAN 1950 - Austria, Belgium, Denmark, Finland, France, Germany, Gibraltar,  
Greece, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland  
EUROPEAN 1979 - Austria, Finland, Netherlands, Norway, Spain, Sweden, Switzerland  
FINLAND HAYFORD 1910 - Finland  
GANDAJIKA BASE - Republic of Maldives  
GEODETIC DATUM 1949 - New Zealand  
ORDNANCE SURVEY OF GREAT BRITAIN 1936 - England, Isle of Man, Scotland,  
Shetland Islands, Wales  
28  
29  
30  
31  
32  
33  
34  
35  
36  
37  
38  
39  
40  
41  
GUAM 1963 - Guam Island  
GUX 1 ASTRO - Guadalcanal Island  
HJORSEY 1955 - Iceland  
HONG KONG 1963 - Hong Kong  
INDIAN - Bangladesh, India, Nepal  
INDIAN - Thailand, Vietnam  
IRELAND 1965 - Ireland  
ISTS O73 ASTRO 1969 - Diego Garcia  
JOHNSTON ISLAND 1961 - Johnston Island  
24  
 
42  
43  
44  
45  
46  
47  
48  
49  
50  
51  
52  
53  
54  
55  
56  
57  
KANDAWALA - Sri Lanka  
KERGUELEN ISLAND - Kerguelen Island  
KERTAU 1948 - West Malaysia, Singapore  
L.C. 5 ASTRO - Cayman Brac Island  
LIBERIA 1964 - Liberia  
LUZON - Mindanao Island  
LUZON - Phillippines (excluding Mindanao Island)  
MAHE 1971 - Mahe Island  
MARCO ASTRO - Salvage Islands  
MASSAWA - Eritrea (Ethiopia)  
MERCHICH - Morocco  
MIDWAY ASTRO 1961 - Midway Island  
MINNA - Nigeria  
NORTH AMERICAN 1927 - Alaska  
NORTH AMERICAN 1927 - Bahamas (excluding San Salvador Island)  
NORTH AMERICAN 1927 - Central America (Belize, Costa Rica, El Salvador,  
Guatemala, Honduras, Nicaragua)  
58  
59  
60  
NORTH AMERICAN 1927 - Canal Zone  
NORTH AMERICAN 1927 - Canada (including Newfoundland Island)  
NORTH AMERICAN 1927 - Caribbean (Barbados, Caicos Islands, Cuba, Dominican  
Republic, Grand Cayman, Jamaica, Leeward Islands, Turks Islands)  
NORTH AMERICAN 1927 - Mean Value (CONUS)  
NORTH AMERICAN 1927 - Cuba  
NORTH AMERICAN 1927 - Greenland (Hayes Peninsula)  
NORTH AMERICAN 1927 - Mexico  
NORTH AMERICAN 1927 - San Salvador Island  
NORTH AMERICAN 1983 - Alaska, Canada, Central America, CONUS, Mexico  
NAPARIMA, BWI - Trinidad and Tobago  
NAHRWAN - Masirah Island (Oman)  
NAHRWAN - Saudi Arabia  
NAHRWAN - United Arab Emirates  
OBSERVATORIO 1966 - Corvo and Flores Islands (Azores)  
OLD EGYPTIAN - Egypt  
OLD HAWAIIAN - Mean Value  
61  
62  
63  
64  
65  
66  
67  
68  
69  
70  
71  
72  
73  
74  
75  
76  
77  
78  
79  
80  
81  
82  
83  
OMAN - Oman  
PICO DE LAS NIEVES - Canary Islands  
PITCAIRN ASTRO 1967 - Pitcairn Island  
PUERTO RICO - Puerto Rico, Virgin Islands  
QATAR NATIONAL - Qatar  
QORNOQ - South Greenland  
REUNION - Mascarene Island  
ROME 1940 - Sardinia Island  
RT 90 - Sweden  
PROVISIONAL SOUTH AMERICAN 1956 - Bolivia, Chile, Colombia, Ecuador, Guyana,  
Peru, Venezuela  
84  
SOUTH AMERICAN 1969 - Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador,  
Guyana,  
Paraguay, Peru, Venezuela, Trinidad and Tobago  
85  
86  
87  
88  
89  
90  
SOUTH ASIA - Singapore  
PROVISIONAL SOUTH CHILEAN 1963 - South Chile  
SANTO (DOS) - Espirito Santo Island  
SAO BRAZ - Sao Miguel, Santa Maria Islands (Azores)  
SAPPER HILL 1943 - East Falkland Island  
SCHWARZECK - Namibia  
25  
 
91  
92  
93  
94  
95  
96  
SOUTHEAST BASE - Porto Santo and Madeira Islands  
SOUTHWEST BASE - Faial, Graciosa, Pico, Sao Jorge, and Terceira Islands (Azores)  
TIMBALAI 1948 - Brunei and East Malaysia (Sarawak and Sabah)  
TOKYO - Japan, Korea, Okinawa  
TRISTAN ASTRO 1968 - Tristan da Cunha  
User defined earth datum  
97  
98  
99  
VITI LEVU 1916 - Viti Levu Island (Fiji Islands)  
WAKE-ENIWETOK 1960 - Marshall Islands  
WORLD GEODETIC SYSTEM 1972  
WORLD GEODETIC SYSTEM 1984  
ZANDERIJ - Surinam  
CH-1903 - Switzerland  
Hu - Tzu - Shan  
Indonesia 74  
Austria  
100  
101  
102  
103  
104  
105  
106  
107  
Potsdam  
Taiwan (modified Hu-Tzu-Shan)  
26  
 
Appendix B  
GPS 35LP Evaluation Kits  
GPS 35LP evaluation materials kit (part number 010-10186-00) is available from Garmin International.  
This kit includes two DB-9 connectors with solder pots, various mounting brackets, hookup wire, technical  
specification, and software to monitor the GPS 35LP outputs and configure the receiver.  
To install the evaluation and configuration software run the program, setup, by using the FILE - RUN  
command in Windows.  
NMEAVWR.EXE  
The NMEAVWR.EXE program in the GARMIN program group can accept NMEA data from either the  
com1 or com2 PC serial port at 1200, 2400, 4800, 9600 or 19200 baud. The default settings are com1 at  
4800 baud. NMEAVWR receives NMEA sentences and displays sentence information in a formatted  
display on the screen.  
The top portion of the screen displays the 5 character identifier of sentences received, the age in  
seconds since the last transmission, and a count of the number of times the sentence has been received.  
The middle portion of the screen displays the most recently received data 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 data can also be  
logged to a file. NMEAVWR can be invoked from a DOS prompt with the following optional parameters:  
<path>nmeavwr [/b:<baud>] [<port>] [log_file.txt]  
where:  
[ ]  
brackets indicate optional parameters  
DOS path to nmeavwr.exe if not in current directory  
baud rate  
PC communications port  
ASCII log file of all received sentences  
<path>  
<baud>  
<port>  
log_file.txt  
Example:  
c:\garmin>nmeavwr /b:9600 com2 log_file.txt  
If no options are used, the defaults are 4800 baud, com1, and no data logging.  
GPSCFG.EXE  
The configuration program GPSCFG.EXE will configure the sensor boards based on user selected  
parameters. Some program features include the ability to download sensor board configuration, maintain  
different configurations in files, and perform sensor board configurations quickly with the use of one  
function key. Online program help is available.  
27  
 
GPS25PM.EXE  
The Garmin Phase Monitor Program, GPS25PM.EXE, provides the following functions:  
- Display and log phase data output from TXD2  
- Upload almanac, position, and time information via 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.  
28  
 
Appendix C  
Phase Output Data Binary Format  
Two records are transmitted once per second by the GPS 35LP. One record contains primarily post-  
process information such as position and velocity information. The second record contains receiver  
measurement information. The records are sent at a default baud rate of 9600 baud, 8 bits, no parity.  
Records begin with a delimiter byte (10 hex). The second byte identifies the record type (28 hex for a  
position record, 29 hex for a receiver measurement). The third byte indicates the size of the data. The  
fourth byte is the first byte of data. The data is then followed by a chksum byte, a delimiter byte (10  
hex), and an end-of-transmission character (03 hex).  
Note - If RTCM-104 differential data is sent to the GPS 35LP the board will reset the Phase Output Data  
baud 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  
- 0x10  
(dle is first byte)  
- 0x28  
(position record identifier)  
- 0x36  
(size of data)  
- cpo_pvt_type  
- one byte chksum  
- 0x10  
(see description below)  
(the addition of bytes between the delimiters should equal 0)  
(dle)  
- 0x03  
(etx is last byte)  
typedef struct  
{
float  
alt;  
float  
epe;  
float  
eph;  
float  
epv;  
int  
fix;  
double  
double  
double  
float  
float  
float  
gps_tow;  
lat;  
lon;  
lon_vel;  
lat_vel;  
alt_vel;  
} cpo_pvt_type;  
alt  
ellipsoid altitude (mt)  
est pos error (mt)  
pos err, horizontal (mt)  
pos err, vertical (mt)  
0 = no fix; 1 = no fix; 2 = 2D; 3 = 3D; 4 = 2D differential; 5 = 3D differential;  
6 and greater - not defined  
epe  
eph  
epv  
fix  
gps_tow  
gps time of week (sec)  
29  
 
lat  
Latitude (rad)  
lon  
Longitude (rad)  
lon_vel  
lat_vel  
alt_vel  
Longitude velocity (mt/sec)  
Latitude velocity (mt/sec)  
Altitude velocity (mt/sec)  
Receiver Measurement Record  
- 0x10  
(dle is first byte)  
- 0x29  
(receiver record identifier)  
- 0xE2  
(size of data)  
- cpo_rcv_type  
- one byte chksum  
- 0x10  
(see below)  
(the addition of bytes between the delimiters should equal 0)  
(dle)  
(etx)  
- 0x03  
typedef struct  
{
unsigned long  
double  
cycles;  
pr;  
unsigned int  
char  
unsigned char  
char  
phase;  
slp_dtct;  
snr_dbhz;  
svid;  
char  
valid;  
} cpo_rcv_sv_type;  
typedef struct  
{
double  
int  
cpo_rcv_sv_type  
} cpo_rcv_type;  
rcvr_tow;  
rcvr_wn;  
sv[12];  
rcvr_tow  
rcvr_wn  
cycles  
pr  
Receiver time of week (sec)  
Receiver week number  
Number of accumulated cycles  
pseudo range (mt)  
phase  
slp_dtct  
to convert to (0 -359.999) multiply by 360.0 and divide by 2048.0  
0 = no cycle slip detected; non 0 = cycle slip detected  
snr_dbhz Signal strength  
svid  
Satellite number (0 - 31) Note - add 1 to offset to current svid numbers  
valid  
0 = information not valid; non 0 = information valid  
30  
 
dle and etx bytes:  
Software written to receive the two records should filter dle and etx bytes as described below:  
typedef enum  
{
dat,  
dle,  
etx  
} rx_state_type;  
char  
in_que[256];  
int  
in_que_ptr = 0;  
rx_state = dat;  
rx_state_type  
void add_to_que( char data )  
{
#define  
#define  
dle_byte 0x10  
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;  
}
}
31  
 
GARMIN Phase Monitor Program - gps25pm.exe  
Command Line Arguments  
default:  
/com1  
/b:9600  
- selects which PC serial port to use for communication - com1, com2 (com1 default).  
- selects the baud rate - 1200, 2400, 4800, or 9600 (9600 default)  
Description:  
GPS25PM.EXE is designed to interface with a Garmin GPS 25 XL or GPS 25LP sensor boards and the  
GPS 35LP sensors. The program will perform the following functions:  
- display and log phase data output by GPS sensors.  
- upload almanac, position, and time information.  
- download almanac and ephemeris information.  
GPS25PM.EXE is a DOS based program and will run on IBM 80286 or greater compatible PCs.  
Displayed Information:  
The GPS25PM.EXE display page is divided into 3 sections. The top-most section contains the following  
information 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. Track - (0 - 359 degrees) - 0.1 degree resolution  
E. Time  
1. GPS time (hours - minutes - seconds) - 1 sec. resolution (not leap second corrected)  
2. Receiver Time of Week (GPS seconds) - 0.00000001 sec. resolution.  
The middle section contains receiver measurement information for satellites which the GPS sensor is  
currently tracking. This information is updated once at second:  
A Satellite Number (1 - 32)  
B. Signal to Noise Ratio (dbHz) - 1 dbHz resolution.  
C. Phase (0 - 359 degrees) - 0.1 degree resolution.  
D. Pseudo Range (meters) - 1 meter resolution.  
E. Accumulated Cycles (cycles) - 1 cycle resolution.  
32  
 
The bottom section contains program messages. Upload and download status messages will appear  
here as well as any program error messages.  
Commands:  
D - Download Almanac:  
The GPS25 sensor will be sent a command to download almanac information. GPS25PM.EXE will  
create the file ALMANAC.DAT and locate it the current working directory. If an ALMANAC.DAT exists in  
the current directory it will be over-written.  
U - Upload Almanac:  
The ALMANAC.DAT file located in the current working directory will be read, converted to GPS25 sensor  
binary format, and sent to the GPS25 sensor. This command will over-write any almanac information  
already in the GPS25 sensor.  
E - Download Ephemeris:  
The GPS25 sensor will be sent a command to download ephemeris information. GPS25PM.EXE will  
create the file EPHEMERS.DAT and locate it in the current working directory. If an EPHEMERIS.DAT  
exists in the current directory it will be over-written.  
P - Position 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 position  
uploading. An integer Latitude and integer Longitude should be entered on the same line separated by a  
space. If the board has not yet obtained a position fix it will restart its startup sequence based on the  
new position and time information.  
R - Record Data  
The program will prompt the user for a data file name. GPS25XL.DAT is the default. Once the file name  
is obtained all information displayed in the top two sections of the screen will be formatted and written to  
the data file. The format of this data file is described in the File Formats section. If the R option is  
selected again, the current file will be saved and closed and a new file will be opened. Data files will be  
over-written if same names are used.  
33  
 
File Formats  
ALMANAC.DAT  
Example almanac entry:  
**** Week 794 almanac for PRN-01 ************  
ID:  
01  
Health:  
000  
Eccentricity:  
3.414630890E-003  
380928.0000  
9.549833536E-001  
-7.771752131E-009  
5153.589843  
8.032501489E-002  
-1.308424592E+000  
2.045822620E+000  
9.536743164E-007  
8.367351256E-011  
794  
Time of Applicability(s):  
Orbital Inclination(rad):  
Rate of Right Ascen(r/s):  
SQRT(A) (m^1/2):  
Right Ascen at TOA(rad):  
Argument of Perigee(rad):  
Mean Anom(rad):  
Af0(s):  
Af1(s/s):  
week:  
Almanac information for satellites with a bad health status will not be included in this file when  
downloaded from the GPS25 sensor and should not be included when uploading to the GPS25 sensor.  
EPHEMERS.DAT  
Example ephemeris entry:  
**** Week 794. Ephemeris for PRN-18 **********  
Ref Time of Clk Parms(s):  
Ref Time of Eph Parms(s):  
Clk Cor, Group Dly(s):  
Clk Correction af1(s/s):  
Clk Correction af2(s/s/s):  
User Range Accuracy(m):  
Eccentricity(-):  
SQRT(A) (m**1/2):  
Mean Motion Cor(r/s):  
Mean Anomaly(r):  
Argument of Perigee(r):  
Right Ascension(r):  
Inclination Angle(r):  
Rate of Right Asc(r/s):  
Rate of Inc Angle(r/s):  
Lat Cor, Sine(r):  
233504.000000  
233504.000000  
-8.280389E-006  
-3.410605E-013  
0.000000E+000  
33.299999  
5.913425E-003  
5.153628E+003  
4.710911E-009  
6.033204E-001  
1.418009E+000  
3.520111E-002  
9.434418E-001  
-8.210699E-009  
4.503759E-010  
1.212582E-005  
2.004206E-006  
-1.490116E-008  
-9.872019E-008  
38.375000  
Lat Cor, Cosine(r):  
Inc Cor, Sine(r):  
Inc Cor, Cosine(r):  
Radius Cor, Sine(m):  
Radius Cor, Cosine(m):  
Issue of Data :  
132.937500  
184  
34  
 
Ephemeris Record  
- 0x10  
(dle is first byte)  
- 0x2A  
- 0x74  
(ephemeris record identifier)  
(size of data)  
- eph_type  
(see description below)  
- one byte chksum (the addition of bytes between the delimiters should equal 0)  
- 0x10  
- 0x03  
(dle)  
(etx)  
typedef struct  
{
/* ephemeris record */  
char svid;  
int wn;  
/* Satellite number (0 - 31)  
/* week number (weeks)  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
*/  
float toc;  
float toe;  
float af0;  
float af1;  
float af2;  
float ura;  
double e;  
double sqrta;  
double dn;  
double m0;  
double w;  
double omg0;  
double i0;  
float odot;  
float idot;  
float cus;  
float cuc;  
float cis;  
/* reference time of clock parameters (s)  
/* reference time of ephemeris parameters (s)  
/* clock correction coefcnt - group delay (s)  
/* clock correction coefficient (s/s)  
/* clock correction coefficient (s/s/s)  
/* user range accuracy (m)  
/* eccentricity (-)  
/* square root of semi-major axis (a) (m**1/2)  
/* mean motion correction (r/s)  
/* mean anomaly at reference time (r)  
/* argument of perigee (r)  
/* right ascension (r)  
/* inclination angle at reference time (r)  
/* rate of right ascension (r/s)  
/* rate of inclination angle (r/s)  
/* argument of latitude correction, sine (r)  
/* argument of latitude correction, cosine (r)  
/* inclination correction, sine (r)  
/* inclination correction, cosine (r)  
/* radius correction, sine (m)  
float cic;  
float crs;  
float crc;  
byte iod;  
} eph_type;  
/* radius correction, cosine (m)  
/* issue of data  
To initiate an ephemeris download for all tracked satellites send the following bytes in sequence:  
0x10, 0x0D, 0x04, 0x02, 0x0C, 0x0, 0x0, 0xE1, 0x10, 0x03  
GPS25PM.DAT  
Example data file entry:  
35  
 
TIM time_of_week week_number  
RCV svid snr (T)rack/(C)ycle_slip phase pseudo_range cycles  
PVT time lat lon alt lat_vel lon_vel alt_vel epe eph epv  
TIM 235537.99855650 794  
RCV 18 50 T 120.2  
RCV 29 50 T 133.2  
RCV 28 45 T 176.5  
RCV 19 47 T 145.2  
RCV 31 45 T 75.8  
RCV 22 42 T 195.1  
RCV 27 36 T 155.2  
RCV 14 39 T 202.3  
PVT 235537.99999842  
TIM 235538.99853500  
RCV 18 50 T 38.8  
RCV 29 50 T 132.4  
RCV 28 45 T 189.5  
RCV 19 47 T 284.6  
RCV 31 45 T 19.0  
RCV 22 42 T 263.0  
RCV 27 36 T 311.7  
RCV 14 39 T 308.3  
PVT 235538.99999827  
TIM 235539.99851349  
RCV 18 50 T 76.6  
RCV 29 50 T 284.4  
RCV 28 45 T 320.8  
RCV 19 47 T 8.3  
RCV 31 45 T 170.2  
RCV 22 42 T 315.9  
RCV 27 36 T 132.4  
RCV 14 39 T 127.4  
PVT 235539.99999812  
TIM 235540.99849199  
RCV 18 50 T 174.9  
RCV 29 50 T 177.7  
RCV 28 45 T 159.6  
RCV 19 47 T 324.7  
RCV 31 45 T 111.8  
RCV 22 42 T 261.7  
RCV 27 36 T 259.1  
RCV 14 39 T 318.7  
PVT 235540.99999797  
TIM 235541.99847244  
RCV 18 50 T 325.5  
RCV 29 50 T 152.1  
RCV 28 45 T 52.4  
RCV 19 47 T 125.3  
RCV 31 45 T 159.4  
RCV 22 43 T 117.1  
RCV 27 36 T 352.1  
RCV 14 39 T 141.3  
PVT 235541.99999977  
19964528.44  
20364313.25  
21135153.13  
21190271.83  
21240354.20  
22849183.41  
24234175.55  
25147694.34  
38.9499588  
794  
19958107.10  
20358247.54  
21128713.01  
21183470.16  
21233441.89  
22843381.08  
24227194.88  
25141899.86  
38.9499550  
794  
19951681.26  
20352180.11  
21122272.68  
21176671.33  
21226528.82  
22837584.50  
24220207.85  
25136106.23  
38.9499512  
794  
19945258.21  
20346113.87  
21115834.07  
21169868.61  
21219615.05  
22831782.87  
24213226.41  
25130310.86  
38.9499474  
794  
2068193  
1950557  
2069992  
2182643  
2216421  
1855826  
2230462  
1845263  
94.7463684 211.7 -0.19 -0.31 0.13 28 16 23  
2101947  
1982431  
2103829  
2218374  
2252746  
1886300  
2267146  
1875708  
94.7463684 212.6 -0.19 -0.30 0.14 28 16 23  
2135704  
2014308  
2137669  
2254110  
2289074  
1916778  
2303835  
1906158  
94.7463684 213.5 -0.19 -0.30 0.13 28 16 23  
2169465  
2046190  
2171514  
2289849  
2325407  
1947261  
2340528  
1936612  
94.7463760 214.4 -0.19 -0.30 0.14 28 16 23  
19938831.69  
20340045.44  
21109392.21  
21163068.15  
21212700.30  
22825981.54  
24206248.88  
25124515.72  
38.9499474  
2203229  
2078075  
2205362  
2325593  
2361743  
1977748  
2377225  
1967071  
94.7463760 215.4 -0.19 -0.30 0.13 28 16 23  
36  
 
GARMIN Corporation  
1200 East 151st Street  
Olathe, KS 66062  
(913)397-8200  
(913)397-8282 FAX  
190-00148-00 Rev. E  
37  
 

Eagle Electronics Fish Finder UltraNavGPS User Manual
Electro Voice Microphone 635N D B User Manual
Electro Voice Microphone PL84 User Manual
Escali Scale Aqua User Manual
Extron electronic Network Card P 2 DA1 USB User Manual
Extron electronic Stereo System 26 018 02 User Manual
Fujitsu Mouse FKB4726 SERIES User Manual
Garmin GPS Receiver 100077202 User Manual
Gateway Laptop 200ARC User Manual
Geemarc Telephone AMPLI600 User Manual