Garmin GPS 18x Manual

The Garmin GPS 18x is a high-sensitivity, waterproof GPS sensor designed for marine, automotive, and OEM applications. It features a built-in WAAS-enabled receiver, NMEA 0183 and RS-232 data output, low power consumption, and a rugged design suitable for harsh environments. Below are key sections for safety, features, installation, configuration, operation, and troubleshooting.

Features at a Glance

Key components: High-sensitivity GPS receiver, waterproof housing, data/power cable, mounting hardware.

Feature	Description
High-Sensitivity Receiver	WAAS-enabled for improved accuracy; tracks in challenging conditions
Waterproof Design	IPX7 rating; withstands immersion in 1 meter of water for 30 minutes
Data Output	NMEA 0183 v3.01 and RS-232 serial data
Power Input	6–40 VDC; low power consumption
LED Status Indicator	Shows power, satellite lock, and data transmission status
Mounting Options	Flush mount or external antenna mount with included hardware
Operating Temperature	-15°C to 70°C (5°F to 158°F)
Dimensions	2.25" diameter x 1.1" height (57.2 mm x 27.9 mm)

Installation

Unpack and inspect contents. Choose a mounting location with clear view of sky.

1. Mount the unit: Use provided hardware for flush or external mounting.
2. Connect the cable: Attach the 4-pin connector to the GPS 18x; route cable to power and data device.
3. Wire connections: Connect red wire to positive DC power (6–40 V), black wire to ground, blue and brown wires to serial data lines as needed.
4. Secure connections: Ensure all connections are waterproof and strain-relieved.

WARNING! Ensure power is off during installation. Mount away from magnetic compasses.

First-Time Setup

Apply power; allow time for initial satellite acquisition.

1. Initial acquisition: May take up to 5 minutes for first fix under open sky.
2. Verify operation: Check LED for solid green (satellite lock).
3. Configure data output: Use connected device or configuration software to set baud rate and NMEA sentences.
4. Test data: Monitor serial output for valid NMEA data.

CAUTION! Do not apply voltage outside 6–40 VDC. Ensure polarity is correct.

Specifications

• Receiver: High-sensitivity, 12 parallel channel GPS with WAAS/EGNOS.
• Update Rate: 1 Hz standard.
• Accuracy: <3 meters RMS with WAAS; <15 meters RMS without WAAS.
• Acquisition Time: Hot start: ~1 second; Warm start: ~38 seconds; Cold start: ~45 seconds.
• Data Protocol: NMEA 0183 v3.01 (GGA, GLL, GSA, GSV, RMC, VTG, ZDA); proprietary Garmin binary.
• Serial Interface: RS-232 (TTL level on some models); configurable baud rates (4800 default).
• Power: 6–40 VDC, 45 mA typical at 12 V.
• Antenna: Built-in patch antenna with ground plane.

Controls and Connections

Physical unit has no user controls; all operation is via power and data connections.

Cable Pinout (4-pin): 1: Power/Data Ground (black), 2: TxD / NMEA Out (brown), 3: RxD / NMEA In (blue), 4: Power +6–40 VDC (red).

LED Indicators: Off = no power; Flashing green = searching for satellites; Solid green = 3D fix acquired; Flashing red = self-test failure.

Configuration & Output

Configure via serial commands or Garmin configuration software.

1. Connect to serial port of computer or host device.
2. Send configuration commands to set baud rate, NMEA sentences, update rate.
3. Save settings to non-volatile memory.
4. Output includes position, velocity, time, satellite data.

Tip: Default baud rate is 4800. Use Garmin Spanner or similar software for configuration.

Operation & Status Indicators

Once powered and configured, unit operates automatically.

1. Power on: LED flashes green during satellite acquisition.
2. Satellite lock: LED turns solid green when 3D fix is achieved.
3. Data output: Serial stream outputs selected NMEA sentences every second.
4. Power down: Unit retains last position and almanac for faster hot starts.

WARNING! Do not obstruct antenna view. Performance degrades near metal structures or underwater.

Mounting Considerations

Mount with clear view of sky, away from obstructions and sources of interference.

For marine use: Mount on highest point possible, away from radar and VHF antennas. For automotive use: Mount on dashboard or roof with magnetic mount (optional). For OEM integration: Ensure ground plane is adequate for optimal performance.

Care & Maintenance

Wipe exterior with damp cloth if dirty. Do not use harsh chemicals. Inspect cable and connections periodically for corrosion or damage.

CAUTION! Do not disassemble unit; no user-serviceable parts inside.

Regulatory Information

FCC Part 15: Class B digital device; complies with limits for digital devices. CE compliant. Contains GPS technology subject to U.S. export controls. For support, visit www.garmin.com/support or contact Garmin International.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No LED illumination	No power or incorrect voltage	Check power connections and voltage (6–40 VDC).
LED flashes green continuously	Insufficient satellite signals	Move to open sky view; ensure antenna not obstructed.
No data output	Incorrect baud rate or wiring	Verify serial settings (4800 default); check TxD/RxD connections.
Poor accuracy	WAAS not available or multipath	Ensure clear sky view; allow time for WAAS acquisition.
LED flashing red	Internal fault	Cycle power; if persistent, contact support.

Reset: Power cycle or send factory reset command via serial.

Service: Contact Garmin Product Support; unit is not user-serviceable.