Onboard GNSS Receiver for LT-1A

cm-level real-time POD

An onboard receiver with undifferenced ambiguity resolution, delivering centimeter-level real-time orbit determination without post-processing.

Geng, Tao · Liu, Qiang · Xie, Xin · Chen, Hanlin · Cheng, Lingyue · Li, Zhiqiang · Zhao, Qile

IEEE Transactions on Instrumentation and Measurement 2025

Specifications

Ambiguity fixing rate

{'zh': '99.8', 'en': '99.8'} %

Ambiguity fixing rate

{'zh': '89.7', 'en': '89.7'} %

Time to first fix

{'zh': '1.0', 'en': '1.0'} min

Time to first fix

{'zh': '11.0', 'en': '11.0'} min

3D orbit accuracy

{'zh': '1.7', 'en': '1.7'} cm

3D orbit accuracy

{'zh': '2.6', 'en': '2.6'} cm

3D orbit accuracy

{'zh': '2.8', 'en': '2.8'} cm

Advantages

Convergence time reduced >60%

With ambiguity fixing, convergence time is reduced by more than 60% for GPS-only and GPS+BDS-3, and by 23% for BDS-3-only, greatly shortening the time to reach high-accuracy orbits.

Ambiguity fixing rate up to 99.8%

With GPS+BDS-3, the ambiguity fixing rate reaches 99.8%, much higher than single systems, and the time to first fix is 1.0 min, ensuring rapid acquisition of fixed solutions.

3D orbit accuracy of 1.7 cm

The real-time 3D orbit accuracy of the GPS+BDS-3 ambiguity-fixed solution is 1.7 cm, a 49.0% improvement over the float solution, meeting centimeter-level real-time POD requirements.

Applications

• LEO satellite POD：Obtain centimeter-level real-time orbits onboard without post-processing, enabling autonomous precise orbit determination.
• satellite constellation operations：Achieve fast convergence and high-accuracy orbits for multiple satellites, simplifying constellation operations and maintenance.
• autonomous spacecraft navigation：Enable high-precision autonomous navigation without ground station support via onboard undifferenced ambiguity resolution.
• GNSS receiver development：Integrates GPS/BDS-3 undifferenced ambiguity resolution, serving as a reference design for next-generation onboard receivers.