Radionavigation Receiver Ambiguity Resolution for BOC Signal Tracking
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Solution Overview
Problem
Satellite radionavigation systems face challenges in accurately demodulating BOC signals due to non-ideal autocorrelation functions caused by phase differential and multi-paths, leading to potential false lock-ons and energy loss.
Innovation Solution
A method for resolving ambiguity by demodulating BPSK signals and using a Kalman filter to generate code and carrier commands, compensating phase differences, and performing differential complex rotation to ensure coherent tracking of BOC signals, thereby reducing the risk of false lock-ons and improving measurement integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BOC signals are demodulated using conventional BPSK methods, then the receiver can process satellite navigation signals, but phase differential and multi-paths cause non-ideal autocorrelation functions leading to false lock-ons and energy loss
Solution Approach 1:
The patent applies preliminary action by performing ambiguity resolution before the tracking phase to ensure the code converges on the main peak of the autocorrelation function. The method includes a transition phase where the receiver deliberately resolves ambiguities caused by phase differential and multi-paths, and a convergence phase where it verifies the code alignment before switching to normal tracking, thereby preventing false lock-ons in advance
Solution Approach 2:
The patent implements feedback through the code loop that continuously monitors the autocorrelation function and adjusts the code phase based on feedback signals from the correlation process. The carrier loop also provides feedback to maintain coherent tracking, and the system uses these feedback mechanisms to correct phase differential effects and ensure the code converges on the correct peak
2Stability of the object's composition
If the receiver uses a code loop and carrier loop for tracking, then it can maintain signal coherence, but phase differential causes the code to converge on incorrect peaks
Solution Approach 1:
The patent segments the tracking process into distinct phases: a transition phase for ambiguity resolution and a tracking phase for coherent tracking. During the transition phase, the receiver uses a simplified correlation process to resolve ambiguities without relying on full coherent tracking, thereby separating the convergence problem from the coherence maintenance problem and allowing each to be optimized independently
3Adaptability or versatility
If the receiver processes signals from multiple satellites, then it can determine position, but non-ideal autocorrelation functions from phase differential affect measurement integrity
Solution Approach 1:
The patent implements universality by developing a unified ambiguity resolution method that works across multiple satellite signals with different characteristics. The receiver applies the same transition phase and convergence phase procedure to all satellites, using universal correlation and discrimination mechanisms that adapt to each satellite's specific signal properties while maintaining consistent reliability across the entire navigation system
Data Source
AI summary
Method of resolving ambiguity for determining the main peak of the autocorrelation function of signals transmitted by a set of satellites and received by a receiver of a radionavigation system, a signal received originating from a satellite comprising two received spectral components right and left, the said method comprising the following steps:the right and left components received are demodulated by a BPSK demodulation methodthe central carrier is tracked by means of a central carrier loop which calculates estimations of central carrier phase errors so as to generate carrier commands,the code is tracked by means of a code loop which calculates instantaneous estimations of code errors so as to generate code commands, wherein the code commands are furthermore generated on the basis of instantaneous estimations of sub-carrier phase errors.