GNSS Carrier Phase Tracking Under Vibration and Shock
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Solution Overview
Problem
Global navigation satellite systems (GNSS) face challenges in accurately tracking carrier phases under high vibration and shock conditions due to the conflicting requirements of individual and common tracking loops, which can lead to inter-channel interference and loss of tracking.
Innovation Solution
An adaptive system that includes a complex of reference signals and an adaptation complex, which expands the effective bandpass of the tracking system to reduce dynamic distortions by generating control signals for numerically-controlled oscillators, allowing for phase and frequency adjustments to improve tracking accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the bandpass of tracking loops is expanded to reduce dynamic errors under vibration and shock, then tracking accuracy improves, but additive interference and clock cycle slips increase
Solution Approach 1:
The tracking system is divided into multiple independent tracking loops, each dedicated to a specific satellite channel. Each loop processes signals from individual satellites separately, allowing optimized bandwidth settings for each channel without affecting others. This segmentation enables narrow-band individual loops to maintain reliability while the collective system achieves wide-band performance through parallel processing of multiple satellites.
2Reliability
If narrow-band individual loops are used to reduce interference, then clock cycle stability improves, but dynamic errors increase under vibration and shock
Solution Approach 1:
Multiple narrow-band individual tracking loops are combined in parallel to achieve the functionality of a wide-band system. By processing signals from multiple satellites simultaneously through separate narrow-band loops and integrating their results, the system achieves the dynamic error reduction capability of wide-band tracking while maintaining the reliability and reduced interference benefits of narrow-band operation.
3Measurement precision
If individual tracking channels are used for each satellite, then measurement precision improves, but inter-channel interference occurs under high vibration and shock
Solution Approach 1:
The receiver architecture segments the tracking function into completely independent individual tracking channels, with each channel dedicated to a specific satellite. Each channel has its own phase-locked loop and processing path, eliminating resource sharing that causes inter-channel interference. This segmentation allows precise carrier phase measurement for each satellite without mutual interference, even under high vibration and shock conditions.
Data Source
AI summary
A system for estimating carrier phases of radio signals in a satellite navigation system receiver for coordinate determination includes a complex of reference signals (CRS), wherein, in each jth satellite channel, a digital reference signal RefSigj, represents an output phase and frequency-controlled oscillation of a corresponding numerically-controlled oscillator (NCOj) for each jth satellite channel, the phase of the oscillation of the NCOj tracking a carrier signal received from the jth satellite; and an adaptation complex (AC) that, in response to vibration or movement of the receiver, changes (expands or reduces) an effective bandpass of the CRS, producing control signals that determine phase and frequency changes in the corresponding NCOj for reducing dynamic distortions in coordinate measurements.