Multi-Antenna Array Line Bias Calibration Without Known Attitude
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Solution Overview
Problem
Conventional multi-antenna array calibration systems require known antenna attitude information to calibrate line biases, which is often unavailable, leading to ineffective spatial processing applications, and existing solutions like short-baseline RTK processing add complexity and resource demands.
Innovation Solution
A processor estimates line biases by calculating differenced carrier phase measurements, removing integer ambiguities, and using estimation algorithms to identify candidate line biases, allowing calibration without knowing the antenna attitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration techniques are used, then accurate spatial processing can be achieved, but the system requires known antenna attitude information which is often unavailable
Solution Approach 1:
The system performs self-calibration by using the received GNSS signals themselves to determine both the antenna attitude and line biases simultaneously. The calibration process does not require external attitude information or separate attitude determination steps - the system serves its own calibration needs using its own received signals and processing capabilities.
Solution Approach 2:
The invention changes the calibration approach from requiring fixed known attitude parameters to dynamically estimating both attitude and line bias parameters simultaneously. By treating attitude as an unknown parameter to be estimated rather than a known input, the system enables calibration without pre-known attitude information.
2Reliability
If short-baseline RTK processing is used to determine antenna attitude, then calibration can be performed, but system complexity and processing resource demands increase
Solution Approach 1:
The invention merges the attitude determination process and line bias calibration process into a single unified estimation procedure. Instead of separately determining attitude using RTK techniques and then using that attitude for calibration, the system combines both tasks into one simultaneous parameter estimation process, reducing overall system complexity and resource requirements.
Solution Approach 2:
The invention extracts the attitude determination step from the traditional calibration workflow and integrates it directly into the line bias estimation process. Rather than treating attitude as a separate prerequisite calculation, the system extracts and combines the essential estimation functions into a single streamlined process that determines both attitude and line biases together.
Data Source
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AI summary
Techniques are provided for estimating a line bias of a multi-antenna array. Diffcarrier phase (CP) values may be calculated based on navigation signals received at two antennas of the multi-antenna array. An integer portion may be removed from each diff-CP value. A baseline vector and a fine line bias estimate may be calculated for each of the plurality of candidate line bias value by executing an algorithm that uses each candidate with fractional diff-CP measurements that are corrected for the candidate that is being tested. Output of a test statistic method (e.g., sum of residual squares) and the smallest fine line bias estimate may be used to identify a particular candidate line bias value. The smallest fine line bias estimate may be added to the chosen candidate to calculate the line bias between the two antennas. Calibration of the multi-antenna array and attitude determination can be jointly performed.