1. GNSS Module Basics

GNSS (Global Navigation Satellite System) includes four major systems: GPS (USA), GLONASS (Russia), Galileo (EU), and BeiDou (China). Multi-mode GNSS modules can receive signals from multiple constellations simultaneously, significantly improving positioning accuracy and reliability.

2. Key Selection Parameters

2.1 Positioning Accuracy

Consumer-grade modules typically offer 2-5 meters of accuracy, while high-precision modules achieve centimeter-level precision. Select the appropriate accuracy level based on your use case to avoid over-engineering and unnecessary costs.

2.2 Time To First Fix (TTFF)

Cold start typically takes 30–40 seconds, while hot start can be reduced to under 1 second. For applications requiring fast response, choose modules that support hot start and Assisted GPS (A-GPS).

2.3 Sensitivity

Tracking sensitivity should be better than -165 dBm; acquisition sensitivity should be better than -148 dBm. High sensitivity ensures reliable performance in weak signal environments such as indoors and underground parking lots.

2.4 Power Consumption

Battery-powered devices must prioritize power efficiency. Select modules that support intermittent positioning and low-power modes to significantly extend battery life.

3. Application Scenario Recommendations

3.1 Vehicle Navigation

Recommend multi-mode GNSS modules supporting GPS, BeiDou, and GLONASS with 2-3 meter positioning accuracy and anti-interference capability.

3.2 Wearable Devices

Prioritize low-power, compact modules with intermittent positioning support and multi-week battery life.

3.3 Drones

Require high-precision RTK modules with centimeter-level accuracy, supporting multi-frequency and multi-system operation to ensure flight safety.

4. Design Considerations

1. Antenna Placement: Keep the antenna area clear and away from metal objects and high-speed signal lines.

2. Impedance Matching: Control 50-ohm impedance for RF traces to minimize signal reflection

3. Power Design: Use an LDO instead of a DC-DC converter to reduce power supply noise interference

4. Shielding Design: Add shielding cans as needed to prevent interference with other RF modules.

5. Summary

Selecting the right GNSS module requires balancing accuracy, power consumption, cost, size, and other factors. We recommend engaging suppliers early in the design phase to secure technical support and reference designs, accelerating your development cycle.