GNSS Attitude Calculation Using Inter-Antenna Phase Differences
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Solution Overview
Problem
Existing state calculating devices face challenges in achieving high precision due to limited antenna installation space and reduced accuracy when the number of GNSS antennas is limited, leading to increased device size and limited base lines.
Innovation Solution
A state calculating device configuration using three GNSS antennas to calculate inter-antenna phase differences, allowing for increased combinations of master and slave antennas, which improves attitude angle estimation accuracy, and includes an error calculating part to estimate calculation errors using geometric distance differences, enabling precise attitude, position, and speed calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distances between GPS antennas are lengthened to improve state calculation accuracy, then measurement precision is improved, but device complexity and installation difficulty increase
Solution Approach 1:
The patent divides the antenna system into multiple GNSS antennas (first, second, and third antennas) that can be independently configured. Each antenna receives signals from multiple satellites, and the system processes signals in segmented combinations (master-slave pairs) to calculate phase differences. This segmentation allows achieving high measurement precision without requiring all antennas to be spaced far apart, as each antenna segment contributes to the overall accuracy through combinatorial processing.
Solution Approach 2:
The patent transitions from considering only spatial distance between antennas to utilizing the dimensional space of satellite signals. By receiving signals from multiple satellites and creating multiple base lines through different antenna combinations, the system achieves accuracy enhancement in the signal processing dimension rather than solely relying on physical antenna separation distance. This allows compact antenna placement while maintaining high measurement precision through multi-dimensional signal processing.
2Measurement precision
If the number of GNSS antennas is increased to improve accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes each GNSS antenna multi-functional by having each antenna serve as both a master and slave in different combinations. The first antenna can be master with second as slave, or slave with first as master, creating multiple base lines. This universal usage pattern allows three antennas to generate six different base lines (AB, AC, BC and their reverses), effectively multiplying the information extraction capability without proportionally increasing hardware complexity.
Solution Approach 2:
The patent merges the measurements from multiple antenna combinations into a unified processing approach. By calculating phase differences from multiple base lines and integrating these measurements through the operation part, the system achieves enhanced attitude angle estimation accuracy. The merging of redundant measurements from different antenna pairs allows the system to achieve high precision with a compact three-antenna configuration rather than requiring a larger distributed array.
3Volume of moving object
If antenna installation space is limited, then device size is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent substitutes the mechanical approach of relying on physical antenna separation distance with a signal processing approach. Instead of achieving accuracy through mechanical spacing of antennas, the system uses phase difference calculations from multiple satellite signals received by compactly arranged antennas. The operation part processes these phase differences to derive accurate state information, replacing the need for large physical baselines with intelligent signal processing that achieves high measurement precision in a compact device volume.
Data Source
AI summary
A small-sized state calculating device which may acquire a highly-precise state calculation value is provided. The state calculating device may include antennas, receiving parts, a phase difference calculating part and an operation part. The receiving parts may calculate carrier phase measurements PYA, PYB and PYC of GNSS signals received by the antennas, respectively. The phase difference calculating part may set the antennas to be switched between a master antenna and a slave antenna, and calculate the plurality of inter-antenna phase differences ΔζAB, ΔζBC and ΔζCA, for every combination of the master antenna and the slave antenna, using the carrier phase measurements PYA, PYB and PYC. The operation part may calculate an attitude angle AT using the plurality of inter-antenna phase differences ΔζAB, ΔζBC and ΔζCA.