Overview
The LC29H series from Quectel tracks L1+L5 dual-frequency signals across GPS, GLONASS, Galileo, BeiDou, and QZSS constellations. An integrated LNA and SAW filter provide high sensitivity (-165 dBm tracking) with strong interference rejection against WiFi and 5G signals.
The Waveshare LC29H GPS/RTK HAT mounts the module on a 40-pin GPIO-compatible board for Raspberry Pi and Jetson Nano, with onboard battery backup, 4 status LEDs, and dual antenna connectors.
Key Features
Section titled “Key Features”- Dual-band tracking: L1+L5 frequencies reduce multipath errors in urban environments
- Multi-constellation: GPS, BDS, GLONASS, Galileo, QZSS simultaneous tracking
- Five variants: Navigation, DR+RTK, DR-only, RTK-only, Base Station
- High sensitivity: -165 dBm tracking, -145 to -147 dBm acquisition
- Low power: under 40 mA @ 5V continuous operation
- AGNSS support: 5-second cold start TTFF (AA variant with EPO injection)
- Onboard ML1220 battery: Ephemeris retention across power cycles
- 4 LED indicators: TX, RX, PPS (positioning lock), PWR
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value |
|---|---|
| Signal Types | GPS, SBAS, QZSS, GLONASS, BeiDou, Galileo |
| Frequency Bands | GPS L1C/A L5, GLONASS L1, BeiDou B1I B2a, Galileo E1 E5a |
| Cold Start | 26 seconds |
| Hot Start | 1 second |
| Acquisition Sensitivity | -145 to -147 dBm (variant-dependent) |
| Tracking Sensitivity | -165 dBm |
| Positioning Accuracy | 1 m CEP (GPS); 0.01 m + 1 ppm CEP (RTK) |
| Max Altitude | 10,000 meters |
| Max Speed | 500 m/s |
| Operating Voltage | 5V (via GPIO or USB) |
| Current Draw | <40 mA @ 5V continuous |
| Operating Temperature | -40 C to +85 C |
| Dimensions | 65 mm x 30.5 mm |
| Communication | UART, I2C |
| Update Rate | 1 Hz (default) |
| Protocol Support | NMEA 0183 v4.10, RTCM 3.x, PAIR, PQTM |
Variant Quick Guide
Section titled “Variant Quick Guide”AA Consumer Navigation
Section titled “ Consumer Navigation”SBAS augmentation (WAAS, EGNOS, MSAS, GAGAN) for sub-meter accuracy in service areas. EASY technology caches and predicts satellite ephemeris for up to 3 days, reducing TTFF after power gaps. AGNSS (EPO injection) further accelerates cold starts to approximately 5 seconds.
Best for: Consumer GPS devices, fleet tracking, personal navigation, geocaching.
BA Dead Reckoning + RTK
Section titled “ Dead Reckoning + RTK”Combines inertial dead reckoning with RTK corrections for continuous centimeter-level positioning through tunnels, parking garages, and dense urban canyons. Accepts vehicle sensor data via CAN bus or wheel tick pulse input.
Best for: Autonomous vehicle prototyping, ADAS, precision agriculture with tunnel traversal, surveying vehicles.
CA Dead Reckoning Only
Section titled “ Dead Reckoning Only”Same DR engine as the BA variant without RTK correction capability. Maintains position continuity through GNSS outages using IMU and optional wheel tick input.
Best for: Vehicle navigation through tunnels, dashcams with continuous position logging, fleet management.
DA RTK Rover
Section titled “ RTK Rover”RTK-only variant optimized for fast convergence to centimeter-level accuracy. No dead reckoning — designed for continuous sky visibility with RTK corrections available.
Best for: Drone landing pads, open-field agriculture, surveying equipment, centimeter-accurate geofencing.
BS Base Station
Section titled “ Base Station”Fixed installation reference station. Outputs raw GNSS observations and RTCM3 correction messages. Survey-in mode autonomously determines antenna position, then switches to fixed-position mode for correction generation.
Best for: Local RTK base stations, rtk2go feeds, CORS network contribution, precision agriculture reference points.
Positioning Principles
Section titled “Positioning Principles”GNSS Overview
Section titled “GNSS Overview”Global Navigation Satellite Systems encompass multiple constellations — GPS (USA), GLONASS (Russia), Galileo (EU), BeiDou (China), QZSS (Japan). Multi-constellation receivers increase the number of available satellites, improving accuracy and reducing multipath errors in challenging environments.
How GPS Positioning Works
Section titled “How GPS Positioning Works”- Satellites continuously broadcast signals containing time and position data
- The receiver measures signal propagation delay (time delay x speed of light = distance)
- Ground monitoring stations maintain atomic clock accuracy within nanoseconds
- Orbital position and clock corrections are uploaded daily to each satellite
- The receiver calculates 3D position using signals from 4+ satellites via trilateration
RTK Technology
Section titled “RTK Technology”Real-Time Kinematic positioning uses carrier-phase measurements instead of just code-phase, resolving integer wavelength ambiguities to achieve centimeter-level accuracy. A fixed base station with a known position generates differential corrections, transmitted to the rover in real-time via NTRIP over mobile networks.
RTK Applications
Section titled “RTK Applications”- Geodetic surveys: Control point establishment and quality validation
- Topographic mapping: Single-operator point capture with real-time accuracy feedback
- Stakeout: Direct coordinate-based positioning without line-of-sight requirements
- Precision agriculture: Centimeter-accurate guidance for planting, spraying, and harvesting
- Drone operations: Precise landing and mission-critical flight paths