GPS 15H & 15L TECHNICAL SPECIFICATIONS
Garmin International, Inc. 1200 E. 151st Street Olathe, KS 66062 USA 190-00266-01, Revision D February 2006
Copyright 20042006 Garmin Ltd. or its subsidiaries Garmin International, Inc. 1200 East 151st Street, Olathe, Kansas 66062, U.S.A. Tel. 913/397.8200 or 800/800.1020 Fax 913/397.8282 Garmin (Europe) Ltd. Unit 5, The Quadrangle, Abbey Park Industrial Estate, Romsey, SO51 9DL, U.K. Tel. 44/0870.8501241 Fax 44/0870.8501251 Garmin Corporation No. 68, Jangshu 2nd Road, Shijr, Taipei County, Taiwan Tel. 886/2.2642.9199 Fax 886/2.2642.9099 All rights reserved. Except as expressly provided herein, no part of this manual may be reproduced, copied, transmitted, disseminated, downloaded, or stored in any storage medium, for any purpose without the express prior written consent of Garmin. Garmin hereby grants permission to download a single copy of this manual onto a hard drive or other electronic storage medium to be viewed and to print one copy of this manual or of any revision hereto, provided that such electronic or printed copy of this manual must contain the complete text of this copyright notice and provided further that any unauthorized commercial distribution of this manual or any revision hereto is strictly prohibited. Information in this document is subject to change without notice. Garmin reserves the right to change or improve its products and to make changes in the content without obligation to notify any person or organization of such changes or improvements. Visit the Garmin Web site (www.garmin.com) for current updates and supplemental information concerning the use and operation of this and other Garmin products. Garmin, AutoLocate, and MapSource are registered trademarks and WAAS Enabled is trademark of Garmin Ltd. or its subsidiaries and may not be used without the express permission of Garmin. Web site address: www.garmin.com

RECORD OF REVISIONS

Revision A B C D
Revision Date 8/16/02 10/22/04 12/27/04 2/17/06
Description Initial Release Revised and Redrawn Revised and Redrawn Revised and Redrawn

ECO # -36010

190-00266-01
GPS 15H & 15L Technical Specifications Page ii

Rev. D

TABLE OF CONTENTS 1 Introduction....1
1.1 Cautions.....1 1.2 Limited Warranty....2 1.3 Overview....3 1.4 Features.....3 1.5 Technical Specifications....4
1.5.1 Physical Characteristics.... 4 1.5.1.1 Size..... 4 1.5.1.2 Weight..... 4 1.5.1.3 Available Connector Options.... 4 1.5.1.4 Antenna Connector.... 4 1.5.2 Electrical Characteristics.... 4 1.5.2.1 Input Voltage..... 4 1.5.2.2 Input Current..... 4 1.5.2.3 GPS Receiver Sensitivity.... 4 1.5.3 Environmental Characteristics.... 4 1.5.4 GPS Performance..... 5 1.5.4.1 Receiver..... 5 1.5.4.2 Acquisition Times.... 5 1.5.4.3 Update Rate.... 5 1.5.4.4 Accuracy..... 5 1.5.5 Interfaces..... 6 1.5.5.1 GPS 15H & 15L Electrical Characteristics... 6 1.5.5.2 Port 1 Protocols.... 6 1.5.5.3 Port 2 Protocols.... 6 1.5.5.4 PPS..... 6 1.5.6 Antenna Specifications.... 6
GPS 15H & 15L Wire Descriptions and Wiring Diagrams..8
2.1 GPS 15H & 15L Wire Descriptions...8 2.2 GPS 15H & 15L Wiring Diagrams....9
Mechanical Characteristics & Mounting...10 GPS 15H & 15L Software Interface...11
4.1 Received NMEA 0183 Sentences....11
4.1.1 4.1.2 4.1.3 4.1.4 4.1.5 4.1.6 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.6 4.2.7 4.2.8 4.2.9 4.2.10 4.2.11 Almanac Information (ALM)....11 Sensor Initialization Information (PGRMI)...12 Sensor Configuration Information (PGRMC)...12 Additional Sensor Configuration Information (PGRMC1)...13 Output Sentence Enable/Disable (PGRMO)...13 Tune DGPS Beacon Receiver (PSLIB)...14 Sentence Transmission Rate.....15 Transmitted Time....16 Global Positioning System Almanac Data (ALM)...16 Global Positioning System Fix Data (GGA)...16 GPS DOP and Active Satellites (GSA)...17 GPS Satellites in View (GSV)....17 Recommended Minimum Specific GPS/TRANSIT Data (RMC)...17 Track Made Good and Ground Speed (VTG)...17 Geographic Position (GLL)....18 Estimated Error Information (PGRME)....18 GPS Fix Data Sentence (PGRMF)...18
4.2 Transmitted NMEA 0183 Sentences....15
GPS 15H & 15L Technical Specifications Page iii
4.2.12 4.2.13 4.2.14 4.2.15
Map Datum (PGRMM)....18 Sensor Status Information (PGRMT)....19 3D velocity Information (PGRMV)....19 DGPS Beacon Information (PGRMB)....19
4.3 Baud Rate Selection....20 4.4 One-Pulse-Per-Second (PPS) Output....20 4.5 Received RTCM Data....20
Appendix A: Earth Datums....21 Appendix B: Binary Phase Output Format..24
Satellite Data Record.....24 Position Record....26 Receiver Measurement Record....26 Sample C Code....27
Appendix C: Changing the Baud Rate in Garmin Mode..28 Appendix D: Ephemeris Data Download (Programming Example)..29
Synopsis.....29 Garmin Binary Format Review....29 Ephemeris Download Procedure.....30 TX Packet: Ephemeris Data Request...30 RX Packet: Acknowledgement....30 RX Packet: Number of Data Packets to Expect...30 TX Packet: Acknowledgement.....30 RX Packet: Ephemeris Data....31 TX Packet: Download Complete....33

Appendix E: Declaration of Conformity..34 LIST OF TABLES AND FIGURES
Table 1: Gain vs. SNR for Given Noise Figure.... 7 Table 2: GPS 15H & 15L Wire Descriptions.... 8 Figure 1: Computer Serial Port Interconnection... 9 Figure 2: PDA Serial Port Interconnection.... 9 Figure 3: Basic NMEA Device Interconnection... 9 Figure 4: GPS 15H-F & 15L-F Dimensions.... 10 Figure 5: GPS 15H-W & 15L-W Outline Drawing... 10 Table 3: NMEA 0183 Output Sentence Order and Size... 15 Table 4: Characters per Second for Available Baud Rates... 15
GPS 15H & 15L Technical Specifications Page iv
INTRODUCTION CAUTIONS 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 15H & 15L sensors are precision electronic NAVigation AIDs (NAVAID), any NAVAID can be misused or misinterpreted, and therefore become unsafe. Use these products at your own risk. To reduce the risk, carefully review and understand all aspects of these Technical Specifications before using the GPS 15H & 15L. When in actual use, carefully compare indications from the GPS to all available navigation sources including the information from other NAVAIDs, visual sightings, charts, etc. For safety, always resolve any discrepancies before continuing navigation.

FCC Compliance

The GPS 15H & 15L sensors comply with Part 15 of the FCC interference limits for Class B digital devices FOR HOME OR OFFICE USE. These limits are designed to provide reasonable protection against harmful interference in a residential installation, and are more stringent than outdoor requirements. Operation of this device is subject to the following 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 equipment 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 equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is 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 the equipment and receiver. Connect the equipment into an outlet on a circuit different from that to which the receiver is connected. Consult the dealer or an experienced radio/TV technician for help.

The GPS 15H & 15L sensors do not contain any user-serviceable parts. Unauthorized repairs or modifications could result in permanent damage to the equipment and void your warranty and your authority to operate these devices under Part 15 regulations.
GPS 15H & 15L Technical Specifications Page 1

LIMITED WARRANTY

This Garmin product is warranted to be free from defects in materials or workmanship for one year from the date of purchase. Within this period, Garmin will at its sole option repair or replace any components that fail in normal use. Such repairs or replacement will be made at no charge to the customer for parts or labor, provided that the customer shall be responsible for any transportation cost. This warranty does not cover failures due to abuse, misuse, accident, or unauthorized alteration or repairs. THE WARRANTIES AND REMEDIES CONTAINED HEREIN ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED OR STATUTORY, INCLUDING ANY LIABILITY ARISING UNDER ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, STATUTORY OR OTHERWISE. THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, WHICH MAY VARY FROM STATE TO STATE. IN NO EVENT SHALL GARMIN BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES, WHETHER RESULTING FROM THE USE, MISUSE, OR INABILITY TO USE THIS PRODUCT OR FROM DEFECTS IN THE PRODUCT. Some states do not allow the exclusion of incidental or consequential damages, so the above limitations may not apply to you. Garmin retains the exclusive right to repair or replace the unit or software or offer a full refund of the purchase price at its sole discretion. SUCH REMEDY SHALL BE YOUR SOLE AND EXCLUSIVE REMEDY FOR ANY BREACH OF WARRANTY. To obtain warranty service, contact your local Garmin authorized dealer or call Garmin Product Support at one of the numbers listed below for shipping instructions and an RMA tracking number. The unit should be securely packed with the tracking number clearly written on the outside of the package. The unit should then be sent, freight charges prepaid, to any Garmin warranty service station. A copy of the original sales receipt is required as the proof of purchase for warranty repairs. Garmin International, Inc. 1200 E 151st Street, Olathe, Kansas 66062 U.S.A. Tel. 913/397.8200 or 800/800.1020 Fax. 913/397.8282 Garmin (Europe) Ltd. Unit 5, The Quadrangle, Abbey Park Industrial Estate, Romsey, SO51 9DL U.K. Tel. 44/0870.8501241 Fax 44/0870.8501251 Online Auction Purchases: Products sold through online auctions are not eligible for rebates or other special offers from Garmin. Online auction confirmations are not accepted for warranty verification. To obtain warranty service, an original or copy of the sales receipt from the original retailer is required. Garmin will not replace missing components from any package purchased through an online auction. International Purchases: A separate warranty is provided by international distributors for units purchased outside the United States. This warranty is provided by the local in-country distributor and this distributor provides local service for your unit. Distributor warranties are only valid in the area of intended distribution. Units purchased in the United States or Canada must be returned to the Garmin service center in the United Kingdom, the United States, Canada, or Taiwan for service.

GPS 15H & 15L Technical Specifications Page 2

OVERVIEW

The GPS 15H & 15L are part of Garmins latest generation of GPS sensor boards designed for a broad spectrum of OEM (Original Equipment Manufacture) system applications. Based on the proven technology found in other Garmin 12-channel GPS receivers, the GPS 15H & 15L track up to 12 satellites at a time while providing fast time-to-first-fix, one-second navigation updates, and low power consumption. The GPS 15H & 15L also provide the capability of FAA Wide Area Augmentation System (WAAS) differential GPS. Their far-reaching capabilities meet the sensitivity requirements of land navigation, the timing requirements for precision timing applications, as well as the dynamics requirements of high-performance aircraft. The GPS 15H & 15L designs utilize the latest technology and high-level circuit integration to achieve superior performance while minimizing space and power requirements. Critical components of the system, such as the digital baseband processor, were designed by Garmin to ensure that the GPS 15H & 15L provide the quality, performance, and capabilities that you have grown to expect from Garmin GPS receivers. The elegant hardware design, combined with software intelligence, makes the GPS 15H & 15L easy to integrate and use. Because they are complete GPS receivers, the GPS 15H & 15L require minimal additional components from an OEM or system integrator. A minimum system must provide the GPS receiver with a source of power, a GPS antenna, and a clear view of GPS satellites within the 1.5 GHz band. For optimum performance, the GPS antenna should be an active antenna with a gain between 10 and 30 dB. If cost constraints prevent the use of an active antenna, a well-matched, efficient, passive antenna attached by a short cable can be used instead. The system may communicate with the GPS 15H & 15L via two RS-232 compatible receive channels and one transmit channel. The GPS 15H & 15L internal FLASH memory allows the GPS to retain critical data such as satellite orbital parameters, last-known position, date and time. End-user interfaces such as keyboards and displays are the responsibility of the application designer.

FEATURES
12-channel GPS receiver tracks and uses up to 12 satellites for fast, accurate positioning and low power consumption. Differential DGPS capability utilizing real-time WAAS or RTCM corrections yielding 35 meter position accuracy (see section 1.5.4.4). Compact, rugged design ideal for applications with minimal space. May be remotely mounted in an out-of-the-way location. Receiver status information can be displayed directly on a chartplotter or PC. User initialization is not required. Once installed and a fix is obtained, the unit automatically produces navigation data. User-configurable navigation mode (2-dimensional or 3-dimensional fix). Highly accurate one-pulse-per-second (PPS) output for precise timing measurements. Pulse width is configurable in 20 millisecond increments from 20 ms to 980 ms. Configurable for binary format carrier phase data output on COM 1 port. Flexible input voltage levels of 3.3 to 5.4 VDC (GPS 15L) or 8.0 to 40 VDC (GPS 15H). Built-in backup battery to maintain real-time clock for up to 21 days. Provision for external power to maintain the real-time clock for longer intervals. FLASH-based program and non-volatile memory. New software revisions upgradeable through Web site download and serial interface. Non-volatile memory does not require battery backup.

GPS 15H & 15L Technical Specifications Page 3

TECHNICAL SPECIFICATIONS

Specifications are subject to change without notice.

Physical Characteristics

1.5.1.1 Size 1.400 (35.56 mm) wide x 1.805 (45.85 mm) long x 0.327 (8.31 mm) high 1.5.1.2 Weight GPS 15H: GPS 15L:
0.53 oz. (15.0 g) 0.50 oz (14.1 g)
1.5.1.3 Available Connector Options GPS 15H-F & 15L-F: 8-pin LIF (Low Insertion Force) flex connector, 1-millimeter pitch. For use with common 1 mm pitch, 8-conductor flex cable, available as Garmin Part Number 310-00040-01. This flex cable mates with common 1 mm pitch, 8pin flex connectors, such as Garmin Part Number 330-00346-08 or Molex Part Number 52793-0890. Refer to the Molex Web site at www.molex.com. GPS 15H & 15L-W: 8-pin JST connector, 1-millimeter pitch. Mating wire harness included (Garmin Part Number 325-00118-01). The connector housing used on this harness is equivalent to JST Part Number SHR-08V-S-B. The 8-wire crimp socket is equivalent to JST Part Number SSH-003T-P0.2. Refer to the JST Web site at www.jst.com.
1.5.1.4 Antenna Connector The GPS 15H & 15L sensors provide a MCX female connector for connection to an active GPS antenna, so the antennas cable should be terminated in MCX male. A suitable antenna is Garmins GA 27C Antenna (Garmin Part Number 010-10052-05). Other antennas that are terminated in male BNC connectors may be adapted via a Garmin MCX to BNC Adapter Cable (Garmin Part Number 010-10121-00).
Electrical Characteristics
1.5.2.1 Input Voltage GPS 15H: 8.0 VDC to 40 VDC unregulated GPS 15L: 3.3 VDC to 5.4 VDC (must have less than 100 mV peak-to-peak ripple)
1.5.2.2 Input Current GPS 15H: 60 mA peak, 50 mA nominal @ 8.0 VDC 40 mA peak, 33 mA nominal @ 12 VDC 15 mA peak, 12 mA nominal @ 40 VDC GPS 15L: 100 mA peak, 85 mA nominal @ 3.3 to 5.0 VDC
1.5.2.3 GPS Receiver Sensitivity -165 dBW minimum
Environmental Characteristics
Operating Temperature: Storage Temperature: -30C to +80C -40C to +90C
GPS 15H & 15L Technical Specifications Page 4

GPS Performance

1.5.4.1 Receiver WAAS Enabled, 12 parallel channel GPS receiver continuously tracks and uses up to 12 satellites (up to 11 with PPS active) to compute and update your position. 1.5.4.2 Acquisition Times Reacquisition: Less than 2 seconds Warm: Cold: AutoLocate: SkySearch: Approx. 15 seconds (all data known) Approx. 45 seconds (initial position, time, and almanac known; ephemeris unknown) 5 minutes (almanac known; initial position and time unknown) 5 minutes (no data known)

1.5.4.3 Update Rate 1 second default; NMEA 0183 output interval configurable from 1 to 900 seconds in 1-second increments. 1.5.4.4 Accuracy GPS Standard Positioning Service (SPS) Position: < 15 meters, 95% typical Velocity: 0.1 knot RMS steady state DGPS (USCG/RTCM) Position: 3-5 meters, 95% typical Velocity: 0.1 knot RMS steady state DGPS (WAAS) Position: < 3 meters, 95% typical Velocity: 0.1 knot RMS steady state PPS Time: 1 microsecond at rising edge of PPS pulse (subject to Selective Availability) Dynamics: 999 knots velocity (only limited at altitude greater than 60,000 feet), 6g dynamics
GPS 15H & 15L Technical Specifications Page 5

Interfaces

1.5.5.1 GPS 15H & 15L Electrical Characteristics True RS-232 output (Port 2 output not used at time of publication), asynchronous serial input compatible with RS-232 or TTL voltage levels, RS-232 polarity. User selectable NMEA 0183 baud rate (300, 600, 1200, 2400, 4800, 9600, 19200, 38400). Factory setting is 4800 baud.
1.5.5.2 Port 1 Protocols Configurable between NMEA 0183 Versions 2.00 and 3.00. ASCII output sentences: GPALM, GPGGA, GPGLL, GPGSA, GPGSV, GPRMC, and GPVTG (NMEA-approved sentences); and PGRMB, PGRME, PGRMF, PGRMM, PGRMT, and PGRMV (Garmin proprietary sentences). NMEA 0183 Outputs (see section 4.2 for full protocol specifications) Position, velocity and time Receiver and satellite status Differential Reference Station ID and RTCM Data age Geometry and error estimates NMEA 0183 Inputs (see section 4.1 for full protocol specifications) Initial position, date and time (not required) Earth datum and differential mode configuration command, PPS Enable, GPS satellite almanac Configurable for binary data output including GPS carrier phase data
1.5.5.3 Port 2 Protocols Real-time Differential Correction input (RTCM SC-104 message types 1, 2, 3, 7, and 9) 1.5.5.4 PPS 1 Hz pulse, programmable width, 1 s accuracy

Antenna Specifications

Should be an active antenna with the following specifications: Gain: Antenna should provide between 10 dB to 30 dB net gain between the antenna feed point and the connection to the GPS 15H & 15L. Consider all amplifier gains, filter losses, cable losses, etc. when calculating the gain. RF Connection: GPS 15H & 15L RF Connection: MCX Female connector (on the GPS 15H & 15L board). Antenna Connection: MCX Male connector (on the end of the antenna cable). Garmin Antenna: GPS 27C (Garmin Part Number 010-10052-05) provides the required MCX Male connector. Other Garmin antennas terminated in a BNC Male connector may also be used if a Garmin MCX to BNC Adapter Cable (Garmin Part Number 010-10121-00) is used. Place the MCX to BNC Adapter Cable between the connector on the end of the antenna cable and the connector on the GPS 15H & 15L.

GPS 15H & 15L Technical Specifications Page 6

Noise Figure/Gain:

The total noise figure on the external antenna must be 7 dB. Refer to the table below.

SNR (dB)

10.0 10.0

Gain (dB)

NF=1.3dB NF=2.3dB NF=3.3dB NF=4.3dB NF=5.3dB NF=6.3dB NF=7.3dB
Table 1: Gain vs. SNR for Given Noise Figure
Properly bias the antenna from an on-board source or an external source: Bias voltage from on-board source: GPS 15H supplies 3.3 VDC to the center conductor of the MCX female, relative to the connector shell ground. GPS 15L supplies 3.0 VDC to the center conductor of the MCX female, relative to the connector shell ground In both the GPS 15H and 15L, the source resistance of the DC supply to the center conductor of the connector is approximately 10 Ohms, which is included as a current limiting resistance. This resistance allows the receiver to survive momentary shorting of the antenna port. The GPS 15H and 15L sensors with serial numbers between 27700000 and 28099999 can detect if the antenna is shorted. GPS 15H and 15L sensors no in the serial number range listed above do not have a provision to protect against a continuously shorted antenna port. The antenna must not draw more than 60 mA. Bias voltage from external source: 4.0 to 8.0 VDC bias through the series combination of an on-board ~10 Ohm current limiting resistance and a Schottky diode. The antenna must not draw more than 60 mA.
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GPS 15H & 15L WIRE DESCRIPTIONS AND WIRING DIAGRAMS
The GPS 15H-F & 15L-F use an eight-contact flex circuit LIF (low insertion force) connector. The GPS 15H-W & 15L-W use an eight-pin JST connector (mating wire harness included). See section 1.5.1.3.
GPS 15H & 15L WIRE DESCRIPTIONS
Signal Name BACKUP POWER Description This input provides external power to maintain the real-time clock. This enables the user to provide backup power if needed for longer than the on-board backup battery provides (roughly 21 days). Input voltage must be between +2.8 and +3.4 VDC. Power and Signal Ground GPS 15L: +3.3 to +5.4 VDC (100 mV ripple) input. Peak operating current is 100 mA. Nominal operating current is 85 mA. This voltage drives an LDO with a nominal 3.0 VDC output. GPS 15H: Unregulated 8.0 to 40 VDC input. Peak operating current is 40 mA @ 12 VDC input. Nominal operating current is 33 mA @ 12 VDC input. This voltage drives a switching regulator with a nominal 3.3 VDC output. Although a regulated supply is not required, the peak-to-peak voltage ripple on this line should be kept to less than 100 mV. Serial Asynchronous Output RS-232 compatible output normally provides serial data which is formatted per NMEA 0183, Version 2.0. This output is also capable of outputting phase data information; see Appendix B: Binary Phase Output Format for details. The NMEA 0183 baud rate is selectable in the range of 300 to 38400 baud. The default baud rate is 4800. First Serial Asynchronous Input RS-232 compatible with maximum input voltage range of -25 < V < 25. This input may also be directly connected to standard 3 to 5 VDC CMOS logic that utilizes RS-232 polarity. The low signal voltage requirement is < 0.6 V, and the high signal voltage requirement is > 2.4 V. Minimum load impedance is 500. This input may be used to receive serial initialization/ configuration data as specified in section 4.1 Received NMEA 0183 Sentences. This input allows the user to supply an external RF bias voltage in the range of 4 VDC to 8 VDC to the active antenna. The voltage should be from a clean, regulated supply and should be well isolated from potential sources of interference. The supply should not share RF current paths with other system devices such as microprocessors or other RF circuits. By default, the unit uses an internal voltage to power the active antenna. Note: This pin is only operational on units whose serial numbers are higher than the serial numbers given below: 010-00240-01 GPS 15H-W serial no. 81301857 010-00240-02 GPS 15L-W serial no. 81408976 010-00240-11 GPS 15H-F serial no. 81901632 010-00240-12 GPS 15L-F serial no. 82001471 One-Pulse-Per-Second Output Typical voltage rise and fall times are 100 ns. Impedance is 250. The open circuit output voltage toggles between the low (0 V) and the high (3.3 V for 15H and 3.0 V for 15L). The default format is a 100 ms wide active-high pulse at a 1 Hz rate, with the pulse width configurable in 20 ms increments. Rising edge is synchronized to the start of each GPS second. This output provides a nominal 450 mVp-p signal into a 50 load. The pulse time measured at the 50% voltage point will be approximately 15 ns earlier with a 50 load than with no load. Second Serial Asynchronous Input This input may be used to receive serial differential GPS data formatted per RTCM SC-104 Recommended Standards For Differential Navstar GPS Service, Version 2.2 (see section 4.5 for more details). Table 2: GPS 15H & 15L Wire Descriptions

Pin # 1

GROUND POWER

PORT 1 DATA OUT

PORT 1 DATA IN

RF BIAS

PORT 2 DATA IN
GPS 15H & 15L Technical Specifications Page 8
GPS 15H & 15L WIRING DIAGRAMS
Figure 1: Computer Serial Port Interconnection
Figure 2: PDA Serial Port Interconnection
Figure 3: Basic NMEA Device Interconnection
GPS 15H & 15L Technical Specifications Page 9
MECHANICAL CHARACTERISTICS & MOUNTING
1. Dimensions in millimeters [inches] 2. Dimension tolerance: +/-0.25 mm [0.01] 3. Use M2 mounting screws
Figure 4: GPS 15H-F & 15L-F Dimensions
1. Dimensions identical to GPS 15H-F and GPS 15L-F 2. Use M2 mounting screws
Figure 5: GPS 15H-W & 15L-W Outline Drawing
GPS 15H & 15L Technical Specifications Page 10
GPS 15H & 15L SOFTWARE INTERFACE
The GPS 15H & 15L interface protocol design on COM 1 is based on the National Marine Electronics Associations NMEA 0183 ASCII interface specification. The COM 2 port can receive differential GPS (DGPS) correction data using the Radio Technical Commission for Maritime Services RTCM SC-104 standard. These standards are fully defined in NMEA 0183, Version 3.0 (copies may be obtained from NMEA, www.nmea.org) and RTCM Recommended Standards For Differential Navstar GPS Service, Version 2.2, RTCM Special Committee No.104 (copies may be obtained from RTCM, www.rtcm.org). The GPS 15H & 15L interface protocol, in addition to transmitting navigation information as defined by NMEA 0183, transmits additional information using the convention of Garmin proprietary sentences. These proprietary sentences begin with the characters, $PGRM, instead of the characters $G that are typical of the standard NMEA 0183 sentences. The characters $P indicate that the sentence is a proprietary implementation and the characters and the characters GRM indicate that it is Garmins proprietary sentence. The letter (or letters) that follow the characters $PGRM uniquely identifies that particular Garmin proprietary sentence. Binary phase data information can alternatively be output on the COM 1 port; see Appendix B: Binary Phase Output Format for details. The following sections describe the NMEA 0183 data format of each sentence transmitted and received by the GPS 15H & 15L.
RECEIVED NMEA 0183 SENTENCES
The following paragraphs define the sentences that can be received on the GPS sensors port. Null fields in the configuration sentence indicate no change in the particular configuration parameter. All sentences received by the GPS sensor must be terminated with <CR><LF>, the ASCII characters for carriage return (0D hexadecimal) and line feed (0A hexadecimal), respectively. The checksum *hh is used for parity checking data and is recommended for use in environments containing high electromagnetic noise. It is generally not required in normal PC environments. When used, the parity bytes (hh) are the ASCII representation of the upper and lower nibbles of the exclusive-or (XOR) sum of all the characters between the $ and * characters, non-inclusive. The hex representation must be a capital letter, such as 3D instead of 3d. Sentences may be truncated by <CR><LF> after any data field and valid fields up to that point will be acted on by the sensor.

2. 3. 4. 5.

GPS 15H & 15L Technical Specifications Page 13
Tune DGPS Beacon Receiver (PSLIB)
The $PSLIB sentence provides the ability to tune a Garmin GBR 21, GBR 23 or equivalent beacon receiver. $PSLIB,<1>,<2>*hh<CR><LF> <1> Beacon tune frequency, 0.0, 283.5325.0 kHz in 0.5 kHz steps <2> Beacon bit rate, 0, 25, 50, 100, or 200 bps If valid data is received, the GPS sensor stores it in the EEPROM and echoes the PSLIB command to the beacon receiver. If the GPS sensor is using any stored beacon frequency other than 0.0, it will tune the beacon receiver once immediately after power up or external reset.
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TRANSMITTED NMEA 0183 SENTENCES
The subsequent paragraphs define the sentences that can be transmitted on COM 1 by the GPS sensor.
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 sensor is referenced to the one-pulse-per-second output pulse immediately preceding the GPRMC sentence, or whichever sentence is output first in the burst (see Table 3 below). The GPS sensor transmits 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 GPS sensor transmits the selected sentences contiguously. The contiguous transmission starts at a GPS second boundary. Determine the length of the transmission with the following equation and Tables 3 and 4: length of transmission = total characters to be transmitted --------------------------------------------characters transmitted per second
Sentence Output by Default? Maximum Characters GPRMC 74 GPGGA 82 GPGSA 66 GPGSV 70 PGRME 35 GPGLL 44 GPVTG 42 PGRMV 32 PGRMF 82 PGRMB 40 PGRMM 32 PGRMT Once per minute 50 Table 3: NMEA 0183 Output Sentence Order and Size Baud Characters per Second Table 4: Characters per Second for Available Baud Rates 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 result in a once per second transmission at the NMEA 0183 specification transmission rate of 4800 baud.

GPS 15H & 15L Technical Specifications Page 15

Transmitted Time

The GPS sensor outputs UTC (Coordinated Universal Time) date and time of day in the transmitted sentences. Before the initial position fix, the on-board clock provides the date and time of day. 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 sensor 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). This document is for sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402, U.S.A. When a positive leap second is required, one second is inserted at the beginning of the first hour (0h 0m 0s) of the day that the positive leap is occurring. The minute containing the leap second is 61 seconds long. The GPS sensor would have transmitted this information for the leap second added December 31, 1998 as follows: $GPRMC,235959,A,3851.3651,N,09447.9382,W,000.0,221.9,071103,003.3,E*69 $GPRMC,000000,A,3851.3651,N,09447.9382,W,000.0,221.9,081103,003.3,E*67 $GPRMC,000000,A,3851.3651,N,09447.9382,W,000.0,221.9,081103,003.3,E*67 $GPRMC,000001,A,3851.3651,N,09447.9382,W,000.0,221.9,081103,003.3,E*66 If a negative leap second should be required, one second is 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 sensor will not transmit the time of day 0h 0m 0s (the zero second) for the day from which the leap second is removed. $GPRMC,235959,A,3851.3650,N,09447.9373,W,000.0,000.0,111103,003.3,E*69 $GPRMC,000001,A,3851.3650,N,09447.9373,W,000.0,000.0,121103,003.3,E*6A $GPRMC,000002,A,3851.3650,N,09447.9373,W,000.0,000.0,121103,003.3,E*69
Global Positioning System Almanac Data (ALM)
Almanac sentences are not normally transmitted. Almanac transmission can be initiated by sending the GPS sensor a $PGRMO,GPALM,1 command. Upon receipt of this command, the GPS sensor transmits available almanac information on GPALM sentences. During the transmission of almanac sentences, other NMEA 0183 data output is suspended temporarily. $GPALM,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>*hh<CR><LF> <field information> can be found in section 4.1.1.

GPS 15H & 15L Technical Specifications Page 25

Position Record

The Position Record has a record identifier of typedef struct { float alt; float epe; float eph; float epv; int fix; double gps_tow; double lat; double lon; float lon_vel; float lat_vel; float alt_vel; float msl_hght; int leap_sec; long grmn_days; } cpo_pvt_data; alt epe eph epv fix gps_tow lat lon lon_vel lat_vel alt_vel msl_hght leap_sec grmn_days Ellipsoid altitude (meters) Est pos error (meters) Pos err, horizontal (meters) Pos err, vertical (meters) 0 = no fix; 1 = no fix; 2 = 2D; 3 = 3D; 4 = 2D differential; 5 = 3D differential; 6 and greater - not defined GPS time of week (sec) Latitude (radians) Longitude (radians) Longitude velocity (meters/second) Latitude velocity (meters/second) Altitude velocity (meters/second) Mean sea level height (meters) UTC leap seconds Garmin days (days since December 31, 1989)
Receiver Measurement Record
typedef struct { unsigned long double unsigned int char unsigned char char char } cpo_rcv_sv_data; typedef struct { double int cpo_rcv_sv_data } cpo_rcv_data; rcvr_tow rcvr_wn cycles pr phase slp_dtct snr_dbhz 190-00266-01 cycles; pr; phase; slp_dtct; snr_dbhz; svid; valid;
rcvr_tow; rcvr_wn; sv[ 12 ];
Receiver time of week (seconds) Receiver week number Number of accumulated cycles Pseudorange (meters) To convert to (0 -359.999) multiply by 360.0 and divide by 2048.= no cycle slip detected; non-zero = cycle slip detected Signal strength - db Hz GPS 15H & 15L Technical Specifications Page 26 Rev. D

svid valid

Satellite number (0-31 and 119-138 for WAAS) Note: Add 1 to offset to current svid numbers. 0 = information not valid; non-zero = information valid

Sample C Code

DLE and ETX bytes: Sample C code to receive the two records should filter DLE and ETX bytes as described below: typedef enum { DAT, DLE, ETX } rx_state_type; /* Declare and initialize static variables */ static char in_que[ 256 ]; static int in_que_ptr = 0; static 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; } } 190-00266-01 GPS 15H & 15L Technical Specifications Page 27 Rev. D

APPENDIX C: CHANGING THE BAUD RATE IN GARMIN MODE
In certain cases, you may need to change the default baud rate of your Garmin GPS receiver while in Garmin mode. Follow these steps to temporarily change the baud rate. Refer to the Garmin Device Interface Specification for details on how to form and parse Garmin packets. At the time of this printing, these specs are available from the technical suppport section of our Web site: http://www.garmin.com/support/commProtocol.html. 1. Turn off all requests by transmitting packet: id = IOP_RQST_DATA (0x1C) data = 0 (16-bit unsigned integer ) 2. 3. The GPS unit will respond by sending a packet with id = IOP_ACK_BYTE (0x06) After you receive the above packet, transmit packet: id = IOP_BAUD_RQST_DATA (0x30) data = baud rate to change to (32-bit unsigned integer; for example, 38400) 4. The GPS unit will respond by sending a packet: id = IOP_BAUD_ACPT_DATA (0x31) data = highest acceptable baud rate closest to what was requested (32-bit unsigned integer; for example, 38361 decimal) 5. Determine the actual baud rate value from the data sent in step 4. This value will be within +/- 5% of the actual baud rate. (For example, the GPS unit might send a baud rate of 38361, which correlates to a baud rate of 38400). If the baud rate in step 5 is acceptable, transmit packet: id = IOP_ACK_BYTE (0x06) data = IOP_BAUD_ACPT_DATA (0x31) 7. 8. 9. Sleep for a small amount of time, about 100 milliseconds, to make sure the packet in (6) was successfully transmitted to the GPS unit. Close the current connection to the GPS unit and immediately open a new connection with the new baud rate obtained in step 5. Immediately after establishing a connection, transmit packet: id = IOP_CMND_DATA (0x0A) data = IOP_ACK_PING (0x3A) 10. The GPS will respond by sending a packet: id = IOP_ACK_BYTE (0x06) data = IOP_CMND_DATA (0x0A) 11. After you receive the above packet, transmit the same packet in step 9 again. id = IOP_CMND_DATA (0x0A) data = IOP_ACK_PING (0x3A) 12. The GPS will respond again with the same packet in step 10. id = IOP_ACK_BYTE (0x06) data = IOP_CMND_DATA (0x0A) 13. The baud rate has been successfully changed upon receiving the above packet. If the GPS unit does not receive these two IOP_CMND_DATA packets within two seconds, it will reset its baud rate to 9600.
GPS 15H & 15L Technical Specifications Page 28
APPENDIX D: EPHEMERIS DATA DOWNLOAD (PROGRAMMING EXAMPLE)

Synopsis

This section describes, using an example, how to download ephemeris information from a Garmin 15, 16, 17 or 18 family GPS unit with the exception of the GPS 15-W and the GPS 15-F.
Garmin Binary Format Review
In order to download the ephemeris data, you must first command the unit to output information in Garmin Binary Format (Garmin mode) instead of the default NMEA output format. To put the unit in Garmin mode, connect to the unit using a terminal program and send the following NMEA sentence: $PGRMO,,G*hh<CR><LF> The checksum *hh is used for parity checking data and is not required, but is recommended for use in environments containing high electromagnetic noise. It is generally not required in normal PC environments. When used, the parity bytes (hh) are the ASCII representation of the exclusive-or (XOR) sum of all the characters between the "$ and * characters, non-inclusive. Sentences may be truncated by <CR><LF> after any data field and valid fields up to that point are acted on by the GPS sensor. The unit stays in Garmin mode until the next power cycle. Now that unit is in Garmin binary format, transmitted and received packets are structured as follows: Byte Description Packet Delimiter Packet ID (type) Data Size Data bytes. Checksum Name DLE ID SIZE DATA Notes 0x10 Packet type Number of bytes in data portion(not including escaped DLEs. See below) Not to exceed 256 bytes. 2s complement of the arithmetic sum of all the bytes from the Packet ID byte to the last DATA byte(inclusive) not counting escaped DLEs. See below DLE 0x10 ETX 0x03

CHKSUM

Packet Delimiter End of Packet
The DLE (0x10) is a delimiter byte used in conjunction with the ETX byte to determine beginning and ending of a packet. However, a 0x10 could appear in the data itself, so if this occurs the byte is escaped with another DLE byte (sometimes referred to as DLE stuffing). In other words, if a DLE occurs in the data, another DLE is transmitted immediately after to indicate that it is a data byte and it is not being used as a delimiter. Note that the size byte of the packet does not count the second DLE byte in an escaped DLE pair in the data field. Since a DLE that is a part of the data will have a second DLE to escape it, a single DLE followed by an ETX byte means that the end of a packet has been reached. In order to interpret these packets properly, one must remove the escaped DLE bytes. This can be achieved using an algorithm similar to the Sample C Code fragment on the previous page.
GPS 15H & 15L Technical Specifications Page 29
Ephemeris Download Procedure
The following is the sequence of events that occurs when downloading ephemeris data. Send a packet containing the command that requests ephemeris data (IOP_DOWN_LOAD_EPH). The packet should look like this: TX Packet: Ephemeris Data Request Byte Description Name HEX Value Delimiter DLE 0x10 Command Data ID IOP_CMND_DATA 0x0A Number of bytes in data SIZE 0x02 Request to D/L ephemeris IOP_DOWN_LOAD_EPH 0x5D Pad to 2 bytes DATA 0x00 Checksum calculation CHKSUM 0x97* Delimiter DLE 0x10 End ETX 0x03 * From now on, checksum calculation will not be shown for every packet example The unit returns an acknowledgement packet that looks like this: RX Packet: Acknowledgement Byte Description Delimiter Acknowledgement ID Number of bytes in data Request to D/L ephemeris Pad Checksum calculation Delimiter End of packet Name DLE IOP_ACK_BYTE SIZE IOP_CMND_DATA DATA CHKSUM DLE ETX HEX Value 0x10 0x06 0x02 0x0A 0x00 ---0x10 0x03

Garmin Proprietary NMEA 0183 Sentences TECHNICAL SPECIFICATIONS
Garmin International, Inc. 1200 E. 151st Street Olathe, KS 66062 USA 190-00684-00, Revision C December 2008
Copyright 2008 Garmin Ltd. or its subsidiaries Garmin International, Inc. 1200 East 151st Street, Olathe, Kansas 66062, USA Tel. (913) 397.8200 or (800) 800.1020 Fax (913) 397.8282 Garmin (Europe) Ltd. Liberty House, Hounsdown Business Park Southampton, Hampshire, SO40 9RB UK Tel. +44 (0) 870.8501241 (outside the UK) (within the UK) Fax +44 (0) 870.8501251 Garmin Corporation No. 68, Jangshu 2nd Road, Shijr, Taipei County, Taiwan Tel. 886/2.2642.9199 Fax 886/2.2642.9099 All rights reserved. Except as expressly provided herein, no part of this manual may be reproduced, copied, transmitted, disseminated, downloaded or stored in any storage medium, for any purpose without the express prior written consent of Garmin. Garmin hereby grants permission to download a single copy of this manual onto a hard drive or other electronic storage medium to be viewed and to print one copy of this manual or of any revision hereto, provided that such electronic or printed copy of this manual must contain the complete text of this copyright notice and provided further that any unauthorized commercial distribution of this manual or any revision hereto is strictly prohibited. Information in this document is subject to change without notice. Garmin reserves the right to change or improve its products and to make changes in the content without obligation to notify any person or organization of such changes or improvements. Visit the Garmin Web site (www.garmin.com) for current updates and supplemental information concerning the use and operation of this and other Garmin products. Garmin is a trademark of Garmin Ltd. or its subsidiaries, registered in the USA and other countries. Web site address: www.garmin.com
RECORD OF REVISIONS Revision A B C Revision Date 04/21/06 04/24/06 12/30/08 Description Initial Release Revised and redrawn Added PGRMW sentence ECO # -37482 58677

190-00684-00

Garmin Proprietary NMEA Sentences Technical Specifications Page ii

Rev. C

TABLE OF CONTENTS Introduction....1
1.1 Garmin Proprietary NMEA Sentences....1
GPS Receiver Software Interface...1
2.1 Received NMEA 0183 Sentences....1
2.1.1 2.1.2 2.1.3 2.1.4 2.1.5 2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 2.2.6 2.2.7 2.2.8 2.2.9 Sensor Initialization Information (PGRMI)... 1 Sensor Configuration Information (PGRMC)... 2 Additional Sensor Configuration Information (PGRMC1)... 2 Output Sentence Enable/Disable (PGRMO).... 3 Additional Waypoint Information (PGRMW)... 3 Sentence Transmission Rate.... 4 Estimated Error Information (PGRME).... 5 GPS Fix Data Sentence (PGRMF).... 5 Aviation Height and VNAV Data (PGRMH)... 5 Map Datum (PGRMM).... 5 Sensor Status Information (PGRMT)... 5 3D velocity Information (PGRMV).... 6 Altitude (PGRMZ).... 6 DGPS Beacon Information (PGRMB).... 6
2.2 Transmitted NMEA 0183 Sentences....4
Appendix A: Earth Datums.....7
LIST OF TABLES AND FIGURES
Table 1: NMEA 0183 Output Sentence Order and Size... 4 Table 2: Characters per Second for Available Baud Rates.... 4
Garmin Proprietary NMEA Sentences Technical Specifications Page iii
INTRODUCTION GARMIN PROPRIETARY NMEA SENTENCES
Garmin Proprietary NMEA sentences are designed for use with Garmin GPS sensors and GPS units in order to interface with external devices for data interpretation and recording. Refer to your Garmin Product Owners Manual to determine the specific sentences supported by your product. NOTE: Not all Garmin GPS units support NMEA interfaces. For those devices that do not support NMEA 0183, refer to the Garmin Device Interface SDK for specific information about the Garmin Protocol. The Garmin Device Interface SDK is located on the Garmin Web site at http://www.garmin.com/support/ commProtocol.html.
GPS RECEIVER SOFTWARE INTERFACE

The interface protocol design of most Garmin products is based on the National Marine Electronics Associations NMEA 0183 ASCII interface specification. This standard is fully defined in NMEA 0183, Version 2.30. Copies may be obtained from NMEA, http://www.nmea.org/. In addition to the standard NMEA 0183 sentences, Garmin GPS receivers may transmit or receive information over their serial interface using NMEA 0183 compliant Garmin proprietary sentences. These proprietary sentences begin with the characters, $PGRM, instead of the characters $G that are typical of the standard NMEA 0183 sentences. The characters $P indicate that the sentence is a proprietary implementation and the characters and GRM indicate that it is Garmins proprietary sentence. The letter (or letters) that follow the characters $PGRM uniquely identifies that particular Garmin proprietary sentence.
RECEIVED NMEA 0183 SENTENCES
The following paragraphs define the sentences that can be received on a GPS units port. Null fields in the configuration sentence indicate no change in the particular configuration parameter. All sentences received by the GPS unit must be terminated with <CR><LF>, the ASCII characters for carriage return (0D hexadecimal) and line feed (0A hexadecimal). The checksum *hh is used for parity checking data and is not required, but is recommended for use in environments containing high electromagnetic noise. It is generally not required in normal PC environments. When used, the parity bytes (hh) are the ASCII representation of the exclusive-or (XOR) sum of all the characters between the $ and * characters, noninclusive. Any letters used in the hex representation must be capitalized, such as 3D instead of 3d. 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 unit.
Sensor Initialization Information (PGRMI)
The $PGRMI sentence provides information used to initialize the GPS sensors set position and time used for satellite acquisition. Receipt of this sentence by the GPS sensor 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 contains the current default values. Current PGRMI defaults (with the exception of the Receiver Command, which is a command rather than a mode) can also be obtained by sending $PGRMIE to the GPS sensor. $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

Garmin Proprietary NMEA Sentences Technical Specifications Page 1
Sensor Configuration Information (PGRMC)
The $PGRMC sentence provides information used to configure a GPS sensors operation. Configuration parameters are stored in non-volatile memory and retained between power cycles. The GPS sensor will echo this sentence upon its receipt if no errors are detected. If an error is detected, the echoed PGRMC sentence contains the current default values. Current default values can also be obtained by sending $PGRMCE to the GPS sensor. $PGRMC,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>*hh<CR><LF> <1> <2> <3> <4> <5> <6> <7> <8> <9> Fix mode, A = automatic, 2 = 2D exclusively (host system must supply altitude), 3 = 3D exclusively Altitude above/below mean sea level, -1500.0 to 10000.0 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 your Appendix A for a list of earth datums and the corresponding earth datum index. User earth datum semi-major axis, 6360000.000 to 6380000.000 meters (.001 meters resolution) User earth datum inverse flattening factor, 285.0 to 310.0 (10-9 resolution) User earth datum delta x earth centered coordinate, -5000.0 to 5000.0 meters (1 meter resolution) 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 0183 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 (e.g., 10 = 10 second filter) <12> Not used <13> Not used <14> Dead reckoning valid time 1-30 (sec) All configuration changes take effect after receipt of a valid value except baud rate. Baud rate change takes effect on the next power cycle or an external reset event.

Additional Sensor Configuration Information (PGRMC1)
The $PGRMC1 sentence provides additional information used to configure the GPS sensor operation. Configuration parameters are stored in non-volatile memory and retained between power cycles. The GPS sensor echos this sentence upon its receipt if no errors are detected. If an error is detected, the echoed PGRMC1 sentence contains the current default values. Current default values can also be obtained by sending $PGRMC1E to the GPS sensor. $PGRMC1,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>*hh<CR><LF> <1> NMEA 0183 output time 1-900 (sec) <2> Binary Phase Output Data, 1 = Off, 2 = On. <3> Automatic Position Averaging when Stopped, 1 = Off, 2 = On <4> No Effect (DGPS beacon frequency 0.0, 283.5 325.0 kHz in 0.5 kHz steps) <5> No Effect (DGPS beacon bit rate 0, 25, 50, 100, or 200 bps) <6> No Effect (DGPS beacon scanning, 1 = Off, 2 = On) <7> NMEA 0183 version 2.30 mode indicator, 1 = Off, 2 = On <8> DGPS mode, W = WAAS Only, N = None (DGPS disabled) <9> Power Save Mode for GPS, P = Power Save mode, N = Normal <10> Adaptive Transmission Enabled, 1 = Off, 2 = On <11> Auto Power Off, 1 = Off, 2 = On <12> Power On with External Charger, 1 = Off, 2 = On Configuration changes take effect immediately, with the exception of Binary Phase Output Data, which takes effect on the next power cycle or a reset event. A reset can be commanded by sending the sentence $PGRMI,,,,,,,R (refer to Section 2.1.1 Sensor Initialization Information (PGRMI)). If the GPS sensor is in the Binary data mode, it is necessary to send the following eight-byte data stream to temporarily change 190-00684-00 Garmin Proprietary NMEA Sentences Technical Specifications Page 2 Rev. C
the data format to NMEA 0183. Then follow by sending a PGRMC1 sentence that turns off the Binary Phase Output Data format: 10 0A 00 CE (Hexadecimal)
Output Sentence Enable/Disable (PGRMO)

The $PGRMO sentence provides the ability to enable and disable specific output sentences. $PGRMO,<1>,<2>*hh<CR><LF> 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) 4 = restore factory default output sentences The following notes apply to the PGRMO input sentence: 1. If the target sentence mode is 2 (disable all), 3 (enable all), or 4 (restore defaults), 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. 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 that can be output by the GPS sensor. If either the target sentence mode field or the target sentence description field is not valid, the PGRMO sentence will have no effect. $PGRMO,GPALM,1 causes the GPS sensor to transmit all stored almanac information. All other NMEA 0183 sentence transmission will be suspended temporarily. $PGRMO,,G causes the COM port to change to Garmin Data Transfer format for the duration of the power cycle. The Garmin mode is required for GPS 10, GPS 15L, GPS 15H, GPS 16, GPS 17, and GPS 18 series product software updates. <1> <2>

2. 3. 4. 5.

Additional Waypoint Information (PGRMW)
The $PGRMW sentence provides the ability to update a waypoints symbol, altitude, and comment. $PGRMW,<1>,<2>,<3>,<4>*hh<CR><LF> Waypoint identifier Altitude in meters Symbol number in Hexadecimal up to FFFF. Uses the enumerated values as defined for symbol_type. <4> Comment string The following notes apply to the PGRMW input sentence: 1. 2. 3. 4. The waypoint identifier must exactly match an existing waypoint on the unit. If the unit cannot find a waypoint that matches the given identifier, the rest of the sentence will be ignored. See Garmin Device Interface Specification 001-0063-00 for enumerated values of symbol_type. If the comment string contains more characters than the unit supports, the unit will ignore any characters beyond the size allotted for comments. Not all units support this sentence. <1> <2> <3>
Garmin Proprietary NMEA Sentences Technical Specifications Page 3
TRANSMITTED NMEA 0183 SENTENCES
The subsequent paragraphs define the sentences that can be transmitted.
Sentence Transmission Rate
Sentences are transmitted with respect to the user selected baud rate. The GPS unit transmits 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 GPS unit transmits the selected sentences contiguously. The length of the transmission can be determined by the following equation and Tables 2 and 3: length of transmission = total characters to be transmitted --------------------------------------------characters transmitted per second

Sentence GPRMC GPGGA GPGSA GPGSV PGRME GPGLL GPVTG PGRMV PGRMF PGRMB PGRMT
Output Rate Maximum Characters Once per record* 74 Once per record* 82 Once per record* 66 Once per record* 70 Once per record* 35 Once per record* 44 Once per record* 42 Once per record* 32 Once per record* 82 Once per record* 40 Once per minute* 50 *if enabled
Table 1: NMEA 0183 Output Sentence Order and Size Baud Characters per Second Table 2: Characters per Second for Available Baud Rates 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 result in a once per second transmission at the NMEA 0183 specification transmission rate of 4800 baud. Some Garmin products implement a one-pulse-per-second output, the rising edge of which is aligned to the UTC second boundary to within one microsecond for all conditions in which the receiver has reported a valid and accurate position for at least the previous four seconds. Regardless of the selected baud rate, the information transmitted by the GPS sensor is referenced to the one-pulse-per-second output pulse immediately preceding the GPRMC sentence, or whichever sentence is output first in the burst (see Table 2 above). NMEA 0183 sentences are listed in order of their occurrence within a record.
Garmin Proprietary NMEA Sentences Technical Specifications Page 4
<1> <2> <3>
Estimated Error Information (PGRME)
$PGRME,<1>,M,<2>,M,<3>,M*hh<CR><LF> 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
<1> <2> <3> <4> <5> <6> <7> <8> <9> <10> <11> <12> <13> <14> <15>
GPS Fix Data Sentence (PGRMF)
$PGRMF,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>*hh<CR><LF> 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 Mode, M = manual, A = automatic Fix type, 0 = no fix, 1 = 2D fix, 2 = 3D fix Speed over ground, 0 to 1051 kilometers/hour Course over ground, 0 to 359 degrees, true Position dilution of precision, 0 to 9 (rounded to nearest integer value) Time dilution of precision, 0 to 9 (rounded to nearest integer value)

<1> <2> <3> <4> <5> <6> <7> <8>
Aviation Height and VNAV Data (PGRMH)
$PGRMH,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>hh<CR><LF> Data status: A = data valid, v = data unusable Vertical speed, feet per minute: negative = down, positive = up VNAV profile error, feet: -999 ft (below VNAV profile) to 999 ft (above VNAV profile) Vertical speed to VNAV target, feet per minute: negative = down, positive = up Vertical speed to next waypoint, feet per minute: negative = down, positive = up Approximate height above terrain, feet (rounded to next lowest 100 feet) Desired track, degrees true Course of next route leg after active waypoint, degrees true

2.2.5 Map Datum (PGRMM)

$PGRMM,<1> *hh<CR><LF> <1> Current map datum (variable length field, for example, WGS 84)
Sensor Status Information (PGRMT)
The Garmin Proprietary sentence $PGRMT gives information concerning the status of a GPS sensor. 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> 190-00684-00 Product, model and software version (variable length field, e.g., GPS 10 SW VER 2.01 BT VER 1.27 764) 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 GPS sensor temperature in degrees C GPS sensor configuration data, R = retained, L = lost Garmin Proprietary NMEA Sentences Technical Specifications Page 5 Rev. C
3D velocity Information (PGRMV)
$PGRMV,<1>,<2>,<3>*hh<CR><LF> True east velocity, 514.4 to 514.4 meters/second True north velocity, 514.4 to 514.4 meters/second Up velocity, 999.9 to 9999.9 meters/second

<1> <2>

Altitude (PGRMZ)
$PGRMZ,<1>, f, <2>,<3>*hh<CR><LF> Current altitude, feet Fix type: 1 = no fix, 2 = 2D fix, 3 = 3D fix
DGPS Beacon Information (PGRMB)
$PGRMB,<1>,<2>,<3>,<4>,<5>,K,<6>,<7>*hh<CR><LF> 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 Beacon receiver communication status (0 = Check Wiring, 1 = No Signal, 2 = Tuning, 3 = Receiving, 4= Scanning) DGPS fix source (R = RTCM, W = WAAS, N = Non-DGPS Fix) DGPS mode, A = Automatic, W = WAAS Only, R = RTCM Only, N = None (DGPS disabled)
Important Note: Garmin units equipped with Sirf technology chipsets do not support this proprietary sentence.
Garmin Proprietary NMEA Sentences Technical Specifications Page 6

APPENDIX A: EARTH DATUMS

The following is a list of the Garmin GPS 10 Earth datum indices and the corresponding earth datum name (including the area of application). NOTE: New datums are always added at the end of the list found on your Garmin GPS device. ADINDAN - Ethiopia, Mali, Senegal, Sudan AFGOOYE - Somalia AIN EL ABD 1970 - Bahrain Island, Saudi Arabia ANNA 1 ASTRO 1965 - Cocos Island ARC 1950 - Botswana, Lesotho, Malawi, Swaziland, Zaire, Zambia, Zimbabwe ARC 1960 - Kenya, Tanzania ASCENSION ISLAND 1958 - Ascension Island ASTRO BEACON E - Iwo Jima Island 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 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 GUAM 1963 - Guam Island GUX 1 ASTRO - Guadalcanal Island HJORSEY 1955 - Iceland Garmin Proprietary NMEA Sentences Technical Specifications Page 7 Rev. C

Garmin Proprietary NMEA Sentences Technical Specifications Page 9
For the latest free software updates (excluding map data) throughout the life of your Garmin products, visit the Garmin Web site at www.garmin.com.
Copyright 2008 Garmin Ltd. or its subsidiaries Garmin International, Inc. 1200 East 151st Street, Olathe, Kansas 66062, U.S.A. Garmin (Europe) Ltd. Liberty House, Hounsdown Business Park, Southampton, Hampshire, SO40 9RB UK Garmin Corporation No. 68, Jangshu 2nd Road, Shijr, Taipei County, Taiwan www.garmin.com December 2008 Part Number 190-00684-00 Rev. C