Tracking Loop Model and Hardware Prototype Verification of GNSS/INS Deep Integration

摘要

There is no systematic and complete theoretical model for signal tracking loop of the GNSS/INS deep integration. And the performance of the deeply-coupled system based on hardware prototype hasn't been fully verified. These limitations block the progress and application of the GNSS/INS deeply-coupled technology. This paper studies the GNSS/INS deeply-coupled technology based on the scalar deep integration for GPS L1 receiver. It establishes the transfer functions between the error sources (including thermal noise, oscillator phase noise, inertial measurement unit (IMU) error, the delay of Doppler aiding infor-mation) and the tracking loop error of the deep integration. And then the steady state tracking model is proposed and analyzed. A hardware/software integrated GNSS/INS scalar deep-coupled prototype is successfully developed, and real-time optimizations are made in terms of the system operation and aiding information delay. The performance of the designed deeply coupled prototype is fully evaluated based on a GPS/IMU hardware simulator and outdoor tests. The result shows that the INS aiding could improve the steady state's tracking performance by extending the integration time to 20 ms and by compressing the bandwidth to 3 Hz under normal dynamic conditions. The proposed error models, designed methods, and hardware prototype developed in this paper can be further applied to the key performance study of the GNSS/INS deeply coupled system, such as the sensitivity and anti-interference under dynamic conditions.