Single Antenna Vehicle Attitude Determination
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Solution Overview
Problem
Existing solutions for determining vehicle attitude using GPS or GNSS require multiple antenna/receiver combinations, which are not feasible for smaller vehicles, and lack the capability to detect spoofing effectively in safety-critical applications.
Innovation Solution
A system and process that uses a single GPS or GNSS antenna/receiver to determine vehicle attitude by modulating sensitivity in azimuth, calculating phase and magnitude of incoming signals, and employing active interference patterns to reject multipath errors and detect spoofing, enabling attitude determination on smaller vehicles and providing anti-jamming capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple antenna/receiver combinations are used to determine vehicle attitude, then measurement precision and reliability are improved, but device complexity and suitability for small vehicles deteriorate
Solution Approach 1:
The patent applies the dynamics principle by electronically steering the single antenna's beam pattern dynamically in azimuth and elevation directions. The antenna is driven with a signal that modulates sensitivity in azimuth, creating a movable reception pattern that sweeps through the sky. This dynamic beam steering allows a single antenna to capture signal information from multiple directions simultaneously, replacing the need for multiple fixed antennas while maintaining attitude determination accuracy.
Solution Approach 2:
The patent transitions from a spatial arrangement of multiple antennas to a temporal/dimensional modulation approach. Instead of having multiple antennas positioned at different locations, the single antenna electronically samples the electromagnetic field from different angular dimensions by modulating its sensitivity pattern. This dimensional transformation allows the system to achieve the information equivalent of multiple antennas using only one physical antenna element.
2Reliability
If multiple antenna systems are used to detect spoofing, then detection capability is improved, but device complexity increases
Solution Approach 1:
The patent uses dynamic beam steering to create time-varying signal reception patterns. By sweeping the antenna's sensitivity pattern through different azimuth and elevation angles, the system can detect inconsistencies in signal sources. If a signal is coming from the wrong angle or all signals are coming from the same angle, the dynamic sampling reveals these anomalies, enabling spoofing detection with a single antenna.
Solution Approach 2:
The system employs feedback mechanisms by continuously monitoring the phase angle and magnitude of received signals relative to the antenna's current beam direction. The demodulated phase information provides feedback about the actual signal source direction, which can be compared against expected satellite positions to detect spoofing or multipath errors.
3Device complexity
If a single antenna is used for attitude determination, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The single antenna achieves enhanced measurement capability through dynamic electronic steering of its beam pattern. By modulating sensitivity in both azimuth and elevation, the antenna effectively samples the electromagnetic field from multiple directions sequentially, gathering sufficient information to compute accurate attitude parameters despite having only one physical antenna element.
Solution Approach 2:
The antenna performs periodic sweeping of its sensitivity pattern through defined azimuth and elevation ranges. This periodic action allows the system to collect multiple measurements at different angular positions, which are then processed to determine the vehicle's attitude. The repeated sampling at different orientations provides the data diversity needed for accurate single-antenna attitude determination.
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
Enables accurate vehicle attitude determination and spoofing detection using a single antenna, suitable for various vehicles, including UAVs and trains, with improved accuracy and reliability compared to traditional multiple antenna systems.
Implementation Method 1
The antenna of the GPS, GNSS or like receiver is driven with a signal that modulates sensitivity in azimuth. The received signal strength is demodulated by the phase at which the antenna is sweeping, and a phase angle and a magnitude for the incoming signal are calculated.
Data Source
AI summary
A system and process that can be used to determine vehicle attitude with only one navigation receiver. In one embodiment, the antenna of the navigation receiver is driven with a signal that modulates sensitivity in azimuth. The received navigation signal strength is demodulated by the phase at which the antenna is sweeping and a phase angle and a magnitude for the incoming signal are calculated. Using this calculated phase angle, magnitude and antenna characteristics, the location of the user (i.e. the navigation receiver) and the location of the navigation satellite, the attitude of the antenna and hence the user or user vehicle can be determined.