Moving Antenna Signal Processing for Spoofer-Resistant Positioning
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Solution Overview
Problem
Existing positioning systems face challenges in accurately determining position when there is little motion between the positioning device and a reference source, or when errors are introduced by moving reflectors or repeater-type spoofers.
Innovation Solution
The system employs a mobile radio receiver with a motion compensated signal processing technique, using a moving antenna to perform motion compensation even when the platform is stationary or moving minimally, thereby differentiating between direct and reflected signals and rejecting spoofer signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion compensated correlation is used to improve signal reception accuracy, then positioning precision is improved, but errors occur when reflectors or spoofers move at similar speed and direction as the receiver platform
Solution Approach 1:
The patent applies dynamics by making the antenna move independently relative to the platform through a movement mechanism. This creates changing geometric relationships between the antenna, platform, and external objects (reflectors/spoofers), allowing the system to differentiate between co-moving and non-co-moving objects over time. The motion of the antenna introduces temporal variations in signal characteristics that enable discrimination against malicious signals.
Solution Approach 2:
The system uses feedback by continuously monitoring signal characteristics and comparing them against expected patterns from legitimate sources. By analyzing how signals change as the antenna moves, the system can identify and reject signals from reflectors or spoofers that do not exhibit the expected geometric relationship with the moving antenna, thereby maintaining positioning reliability.
2Adaptability or versatility
If a movement mechanism is added to enable motion compensation when the platform is stationary, then signal reception capability is improved, but device complexity increases
Solution Approach 1:
The patent introduces a movement mechanism that enables the antenna to move independently of the platform, providing dynamic positioning capability. This allows the system to perform motion compensation even when the platform is stationary, significantly improving signal reception capability and adaptability to different operating conditions.
Solution Approach 2:
The movement mechanism serves multiple functions: it enables motion compensation for stationary platforms, improves signal reception from multiple angles, and provides the geometric variation needed to detect and reject reflector and spoofer signals. This multi-functionality justifies the added complexity by delivering broad operational benefits.
Data Source
AI summary
A system is disclosed and comprises a mobile platform, an antenna configured to receive a signal from a remote source in a first direction, a movement mechanism mounted to the platform, wherein the antenna is mounted to the movement mechanism, the movement mechanism being configured to move the antenna relative to the platform, and a controller configured to: generate a local signal, determine a component of motion of the antenna in the first direction, correlate the local signal with the received signal to provide a correlation signal, and motion compensating at least one of the local signal, the signal from the remote source, and the correlation signal based on the determined motion of the antenna in the first direction.