Adaptive GNSS Carrier Phase Tracking Under Shock and Vibration
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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, leading to dynamic errors and potential inter-channel interference.
Innovation Solution
An adaptive system that includes a complex of reference signals and an adaptation complex, which expands the effective bandpass of individual satellite channels 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 is improved, but additive interference and clock cycle slips increase
Solution Approach 1:
The tracking system is divided into multiple independent satellite channels, each with its own Phase Lock Loop (PLL) for carrier phase tracking. This segmentation allows individual optimization of each channel's bandpass characteristics while maintaining overall system performance under vibration and shock conditions.
Solution Approach 2:
The patent implements adaptive bandpass filtering where the tracking loop bandpass is dynamically adjusted based on detected vibration and shock conditions. During high-dynamic periods, the bandpass is narrowed to reduce interference and prevent cycle slips, while during stable periods it is widened to reduce tracking errors.
2Object-generated harmful factors
If individual tracking channels are used for each satellite to reduce inter-channel interference, then channel independence is improved, but the ability to track common disturbances is reduced
Solution Approach 1:
The patent combines individual satellite channel tracking with a common disturbance tracking mechanism. Correlator outputs from multiple satellite channels are processed to detect common disturbances (vibration, shock, platform motion), which are then used to adjust the tracking parameters of all channels simultaneously, maintaining both independence and common response capability.
Solution Approach 2:
The system implements feedback loops where the output of correlators in individual satellite channels is fed back to detect common disturbances. This feedback information is used to dynamically adjust the bandpass and other parameters of all tracking loops, enabling coordinated response to platform-level disturbances while maintaining channel independence for satellite-specific tracking.
Data Source
AI summary
System for estimating carrier phases, including a receiver that receives radio signals from satellites; the radio signals are converted into digital signals; a plurality of channels, each including a correlator receives digital signals and outputs (I, Q) components for one satellite; a reset accumulator that receives (I, Q) components, accumulates them over multiple cycles of a pseudorandom code and outputs accumulated (Is, Qs); a discriminator that generates a tracking error signal; a CCLF (common controlled loop filter) receives the tracking error signal and outputs a frequency control signal and a phase control signal; NCO receives the frequency and phase control signals, and outputs a reference signal. CCLF also receives correction signals based on the radio signals due to shock, vibration or acceleration. NCO control signals depend on the correction signals due to a change in an effective bandwidth of the CCLF to reduce coordinate measurement dynamic distortions.