Symmetric Bistatic Radar Phase Correction Using Beat Signals
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Solution Overview
Problem
Existing radar systems face challenges in effectively reducing phase noise, particularly in bistatic radar arrays, which affects the accuracy of distance and velocity measurements, especially in applications requiring detection of moving objects at higher speeds and distances.
Innovation Solution
A method and apparatus for reducing phase noise in radar return signals using asymmetric linear antenna arrays, involving the generation of beat signals, complex conjugate multiplication, and phase estimation correction terms to enhance phase coherence and reduce noise levels in radar return signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase noise reduction techniques are applied in bistatic radar arrays, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent segments the phase noise correction process into distinct computational steps: generating beat signals from transmitted and received signals, computing complex conjugates, performing multiplications to obtain phase error estimates, and applying corrections to range and velocity measurements. This segmentation allows each processing stage to be optimized independently while maintaining overall measurement precision.
Solution Approach 2:
The patent applies preliminary phase noise correction to the beat signals before performing range and velocity measurements. By estimating and correcting phase errors in advance using complex conjugate multiplication and phase unwrapping operations, the system prevents phase noise from degrading subsequent measurement accuracy, thereby improving overall measurement precision without requiring complex real-time correction during measurement.
2Measurement precision
If asymmetric linear antenna arrays are used in bistatic radar, then direction resolution improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements feedback through phase error estimation and correction using beat signals. By continuously monitoring phase deviations in the received signals and applying corrective phase adjustments based on complex conjugate multiplication, the system compensates for manufacturing tolerances in antenna spacing, thereby maintaining high direction resolution without requiring extremely tight manufacturing precision.
Solution Approach 2:
The patent changes the operational parameters of the antenna array by using asymmetric spacing configurations that are optimized for direction resolution. Rather than requiring perfect symmetric spacing, the system adjusts the asymmetric parameters and applies corresponding phase corrections to achieve the desired directional performance, thereby reducing the stringency of manufacturing precision requirements.
3Measurement precision
If multiple beat signals are processed for phase estimation, then phase noise reduction improves, but processing time increases
Solution Approach 1:
The patent maintains continuous phase noise reduction by processing multiple beat signals in a continuous manner rather than sequentially. The complex conjugate multiplication and phase unwrapping operations are performed continuously on overlapping signal segments, allowing phase noise reduction to occur without interrupting the radar measurement process, thereby minimizing processing time loss while maintaining high phase noise reduction effectiveness.
Data Source
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AI summary
Phase noise reduction is described for symmetric bistatic radar. In one example, a first beat signal is generated of a second signal received at a first antenna and a third beat signal is generated at a second antenna of a first linear antenna array. A second beat signal is generated of a first signal received at a first antenna of a second linear antenna array. The first beat signal and the third beat signal are multiplied with the complex conjugate of the second beat signal to generate products that are combined to generate a phase estimation correction term that is applied to first and second sets of radar return signals.