GPS Roll Rate Measurement Using Phase Difference Processing
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Solution Overview
Problem
Traditional methods for measuring the roll rate and roll angle of spinning platforms, especially in jamming environments, are costly and ineffective due to reliance on expensive inertial systems and susceptibility to interference, while existing GPS-based solutions struggle with accuracy and antijam performance at high spin rates.
Innovation Solution
A GPS-based system using multiple antennas with self-adaptive beam-forming and Sample Matrix Inversion (SMI) technique to suppress jamming signals, allowing for accurate roll rate and roll angle measurements by processing phase and amplitude differences, even at high spin rates and in the presence of interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional inertial rate indicators (MEMS gyroscopes) are used to measure roll rate and angle, then autonomous on-board guidance is provided and immunity to jamming is achieved, but the system becomes expensive and requires calibration prior to use
Solution Approach 1:
The patent replaces mechanical inertial sensors (MEMS gyroscopes) with an electromagnetic field-based GPS signal processing system. By using multiple GPS antennas and processing the phase and amplitude differences of received signals through self-adaptive beam-forming, the system achieves roll measurement without mechanical moving parts, thereby eliminating calibration requirements and reducing cost while maintaining anti-jamming capability through signal processing
Solution Approach 2:
The patent introduces self-adaptive beam-forming signal processing as an intermediary between the GPS antennas and the roll measurement output. This intermediary process suppresses jamming signals and extracts pure GPS satellite signals, enabling accurate roll measurement without direct mechanical sensing, thus achieving reliability without the complexity of calibrated inertial instruments
2Reliability
If magnetometers are used to measure roll rate and angle, then autonomous on-board guidance is provided, but the system becomes expensive and susceptible to interference from local magnetic fields
Solution Approach 1:
The patent replaces magnetic field-based magnetometers with electromagnetic wave-based GPS signal processing. By measuring phase and amplitude differences of GPS radio waves received at multiple antennas, the system achieves autonomous roll measurement without being affected by local magnetic fields, thereby eliminating the harmful susceptibility to magnetic interference while maintaining autonomy
Solution Approach 2:
The patent uses self-adaptive beam-forming as an intermediary to process GPS signals and eliminate jamming interference. This signal processing intermediary extracts pure satellite signals from the presence of local electromagnetic interference, enabling reliable measurement without the magnetic field susceptibility inherent in magnetometer-based systems
3Device complexity
If existing GPS-based solutions are used to measure roll rate and angle, then cost-effectiveness is improved, but accuracy and antijam performance deteriorate at high spin rates
Solution Approach 1:
The patent implements a dynamic self-adaptive beam-forming algorithm that continuously adjusts to the platform's high spin rate conditions. By dynamically processing the time-varying phase and amplitude differences of GPS signals received at multiple rotating antennas, the system maintains measurement accuracy despite the high spin rates, overcoming the limitations of static GPS-based solutions
Solution Approach 2:
The patent applies preliminary signal processing through self-adaptive beam-forming to suppress jamming signals before roll measurement extraction. This preliminary action of cleaning the GPS signals ensures that subsequent roll rate and angle measurements remain accurate even at high spin rates, preventing the degradation seen in existing GPS-based solutions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Provides a cost-effective and reliable means to measure roll rate and roll angle in jamming environments, maintaining accuracy without the need for expensive inertial instruments and ensuring visibility of GPS satellites at all roll angles, with improved antijam performance and reduced errors.
Implementation Method 1
processing phase and amplitude differences
Implementation Method 2
processing phase and amplitude differences
Implementation Method 3
self-adaptive beam-forming bulling, and the clean satellite signals rendered
Implementation Method 4
Sample Matrix Inversion (SMI) technique to suppress jamming signals
Data Source
AI summary
A system and method for determining the roll rate and roll angle of a spinning platform by using the measured phase and/or amplitude differences between the GPS satellite signals received on two or more antennas. The measured signal differences and the navigation solution from a GPS receiver are processed in a roll filter to obtain the desired information. Data from non-GPS measurement sources is optionally provided to update the navigation solution. Although of wide applicability, the invention is uniquely suited to the measurement of roll rates and roll angles of fast spinning platforms with small baselines in the presence as well as in the absence of jamming, and where the antennas are separated from each other by distances that are a fraction of the GPS signal wavelength.