Carrier Phase Relative Positioning with IMU Attitude Validation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing GPS/INS systems face challenges in quickly and accurately determining integer ambiguities, especially when only a single baseline is available or under conditions with limited GPS satellites and multipath disturbances, leading to a low success rate in identifying correct integer ambiguity sets.
Innovation Solution
A carrier phase-based relative positioning apparatus that calculates attitude information using inertial measurement unit (IMU) observables before integer ambiguity determination, allowing for the evaluation and validation of integer ambiguity candidates, including roll, pitch, and heading angles, to achieve a high success rate even with a single baseline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If validation of integer ambiguity candidate sets is performed using only baseline length information from a single baseline, then the apparatus complexity is reduced, but the success rate of identifying correct integer ambiguity sets decreases to an unacceptably low level
Solution Approach 1:
The patent applies multi-functionality by using the IMU to provide multiple types of a priori information (roll angle, pitch angle, heading angle) for validating integer ambiguity candidates, rather than relying on a single validation method. This allows the system to achieve high validation success rate with a single baseline, eliminating the need for multiple baselines while maintaining reliability.
Solution Approach 2:
The IMU acts as an intermediary that provides attitude information (roll, pitch, heading angles) to validate integer ambiguity candidates. This intermediary information source enables the system to achieve reliable validation without requiring multiple baselines, thus reducing apparatus complexity while maintaining high success rate.
2Reliability
If multiple GPS antennas and baselines are used to validate integer ambiguity candidates, then the success rate improves, but the apparatus size and cost increase
Solution Approach 1:
The patent extracts and utilizes attitude information (roll, pitch, heading angles) from the IMU as a separate information source for validating integer ambiguity candidates. This extracted information allows the system to achieve reliable validation with a single baseline, eliminating the need for multiple antennas and reducing apparatus size.
3Reliability
If multiple GPS antennas and baselines are used to validate integer ambiguity candidates, then the success rate improves, but the cost of the apparatus increases
Solution Approach 1:
The system uses the IMU, which is already part of the GPS/INS integrated apparatus, to provide attitude information for validating integer ambiguity candidates. This self-service approach eliminates the need for additional GPS antennas and baseline measurement equipment, reducing apparatus cost while maintaining high validation success rate.
Data Source
AI summary
A carrier phase-based relative positioning apparatus includes a plurality of antennas fixedly mounted on a moving body for receiving positioning signals from satellites, an inertial measurement unit (IMU) for measuring accelerations and angular velocities of the moving body, a reference attitude calculator for calculating attitude information about the attitude of the moving body from observables of the IMU at least before an integer ambiguity candidate is initially determined, an integer ambiguity estimator for estimating integer ambiguity candidates from the positioning signals received by the antennas, and an integer ambiguity validator for evaluating correctness of the integer ambiguity candidates estimated by the integer ambiguity estimator.