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GPS 20x
TECHNICAL
SPECIFICATIONS
Garmin International, Inc.
st
1200 E. 151 Street
Olathe, KS 66062 USA
190-00880-00, Revision A
January 2008
a
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© 2008 Garmin Ltd. or its subsidiaries Garmin International, Inc. st 1200 East 151 Street, Olathe, Kansas 66062, U.S.A. Tel. 913/397.8200 or 800/800.1020 Fax 913/397.8282 Garmin (Europe) Ltd. Liberty House, Hounsdown Business Park, Southampton, Hampshire, SO40 9RB, U.K. Tel. +44 (0) 870.8501241 (outside the UK) 0808 2380000 (within the UK) Fax +44 (0) 870.8501251 Garmin Corporation nd No. 68, Jangshu 2 Road, Shijr, Taipei County, Taiwan Tel. 886/2.2642.9199 Fax 886/2.2642.9099 Al
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TABLE OF CONTENTS 1 Introduction..............................................................................................................................1 1.1 Cautions...........................................................................................................................................................1 1.2 Limited Warranty ............................................................................................................................................2 1.3
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1 INTRODUCTION 1.1 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 20x is a precision electronic NAVigation AID (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 20x. When in actual use, c
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1.2 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
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1.3 OVERVIEW The GPS 20x includes an embedded receiver and an antenna. The GPS 20x tracks multiple satellites at a time while providing fast time-to-first-fix navigation updates once per second. This generation of GPS sensors includes the capability of FAA Wide Area Augmentation System (WAAS) differential GPS. The GPS 20x design uses the latest technology and high-level circuit integration to achieve superior performance while minimizing space and power requirements. The hardware capability
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1.5 TECHNICAL SPECIFICATIONS Specifications are subject to change without notice. 1.5.1 Physical Characteristics 1.5.1.1 Size 1.7 in. (42.8 mm) long × 1.3 in. (32.4 mm) wide × 0.5 in. (12 mm) in height 1.5.1.2 Weight 1.1 oz (31.7 g) 1.5.1.3 Color Silver 1.5.1.4 Case Material Polycarbonate/Acrylonitrile-Butadiene-Styrene (PC/ABS) 1.5.1.5 Cable Length 1 meter 1.5.2 Electrical Characteristics 1.5.2.1 Input Voltage 4.4–5.5 Vdc 1.5.2.2 Input Current 110 mA @ 5.0 Vdc 1.5.2.3 GPS Re
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1.5.3.4 Accuracy • GPS Standard Positioning Service (SPS) Position: < 15 meters, 95% typical Velocity: 0.1 knot RMS steady state • WAAS Position: < 3 meters, 95% typical Velocity: 0.1 knot RMS steady state • Dynamics: 999 knots velocity (only limited at altitude greater than 60,000 feet), 2g dynamics 1.5.4 Interfaces 1.5.4.1 GPS 20x Electrical Characteristics USB 2.0 full-speed protocol compatible, as well as USB 1.1 full-speed protocol. 1.5.4.2 Garmin Interface and Garmin USB Pr
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2 MECHANICAL CHARACTERISTICS 1.7 in. (42.8 mm) 1.3 in. (32.4 mm) Figure 1. GPS 20x Top Case Dimensions 1.7 in. (42.8 mm) 0.5 in. (12 mm) Figure 2. GPS 20x Side View 0.5 in. (12 mm) Figure 3. GPS 20x End View 190-00880-00 GPS 20x Technical Specifications Rev. A Page 6
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3 GPS 20x SOFTWARE INTERFACE The GPS 20x transmits using the Garmin USB interface. The Garmin USB interface is discussed in the Garmin Device Interface Specification found in the Garmin Device Interface SDK located on the Garmin Web site at: www.garmin.com/support/commProtocol.html. You can configure the GPS 20x to transmit binary data information over the USB interface. Refer to Appendix B: Garmin Binary Output Format. 3.1 TRANSMITTED NMEA 0183 SENTENCES The following paragraphs define
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3.1.2 Transmitted Time The GPS sensor outputs Coordinated Universal Time (UTC) 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 measurement pulse output. The GPS sensor uses information obtained from the GPS satellites to add or delete UTC leap seconds and correct the tr
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3.1.4 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 <1> Mode, M = Manual, A = Automatic <2> Fix type, 1 = not available, 2 = 2D, 3 = 3D <3> PRN number, 01 to 32, of satellite used in solution, up to 12 transmitted (leading zeros will be transmitted) <4> Position dilution of precision, 0.5 to 99.9 <5> Horizontal dilution of precision, 0.5 to 99.9 <6> Vertical dilution of precision, 0.5 to 99.9 3.1.5 GPS Satellite
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3.1.7 Sensor Status Information (PGRMT) The Garmin Proprietary sentence $PGRMT gives information concerning the status of the 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 <1> Product, model and software version (variable length field, for example, “GPS 20x VER 2.05”) <2> No Effect (This field is not used on this model and is included only for backwards compatibility) <3> No Effect (This
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APPENDIX A: EARTH DATUM LIST The following is a list of the Garmin GPS 20x Earth datum indices and the corresponding earth datum name (including the area of application): 0 ADINDAN–Ethiopia, Mali, Senegal, Sudan 9 AUSTRALIAN GEODETIC 1984–Australia, Tasmania Island 10 ASTRO DOS 71/4–St. Helena Island 11 ASTRONOMIC STATION 1952–Marcus Island 12 ASTRO B4 SOROL ATOLL–Tern Island 13 BELLEVUE (IGN)–Efate and Erromango Islands 14 BERMUDA 1957–Bermuda Islands 15 BOGOTA OBSERVATORY–Colombia 1
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44 KERTAU 1948–West Malaysia, Singapore 45 L.C. 5 ASTRO–Cayman Brac Island 46 LIBERIA 1964–Liberia 47 LUZON–Mindanao Island 48 LUZON–Phillippines (excluding Mindanao Island) 49 MAHE 1971–Mahe Island 50 MARCO ASTRO–Salvage Islands 51 MASSAWA–Eritrea (Ethiopia) 52 MERCHICH–Morocco 53 MIDWAY ASTRO 1961–Midway Island 54 MINNA–Nigeria 55 NORTH AMERICAN 1927–Alaska 56 NORTH AMERICAN 1927–Bahamas (excluding San Salvador Island) 57 NORTH AMERICAN 1927–Central America (Belize, Costa Rica, El
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83 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 SOUTH ASIA–Singapore 86 PROVISIONAL SOUTH CHILEAN 1963–South Chile 87 SANTO (DOS)–Espirito Santo Island 88 SAO BRAZ–Sao Miguel, Santa Maria Islands (Azores) 89 SAPPER HILL 1943–East Falkland Island 90 SCHWARZECK–Namibia 91 SOUTHEAST BASE–Porto Santo and Madeira
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APPENDIX B: GARMIN BINARY OUTPUT FORMAT In Binary Output mode, GPS 20x will transmit packets once per second. The records must be enabled by commands to the unit. Refer to the Garmin Device Interface Specification found in the Garmin Device Interface SDK for details on how to form and parse Garmin packets over USB. At the time of this printing, this document is located on the Garmin Web site at: www.garmin.com/support/commProtocol.html. The ID of each command should be 10 decimal to signify
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Satellite Data Record The satellite data has a record ID of 0x72 with 84 (0x54) data bytes. The data bytes contain data for 12 satellites as described below. typedef struct { uint8 svid; //space vehicle identification (1–32 and 33–64 for WAAS) uint16 snr; //signal-to-noise ratio uint8 elev; //satellite elevation in degrees uint16 azmth; //satellite azimuth in degrees uint8 status; //status bit-field } cpo_sat_data; The status bit field represents a set of booleans descri
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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 Ellipsoid altitude (meters) epe Estimated position error (meters) eph Position error, horizontal (meters) epv Position error, vertical (meters) fix 0 = no fix; 1 = no
