Radar Communications Oversampling Range Migration
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Solution Overview
Problem
High relative speeds between radar targets and radar systems can cause range migration, where the range peak response straddles across multiple range cells, undermining Doppler coherent integration and angle estimation processes, especially in high range resolution systems.
Innovation Solution
The transformation of radar signal samples into the time-frequency domain, oversampling, and subsequent inverse transformation to provide resampled reflections, which are used to construct a range response characterizing the target, thereby mitigating range migration effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high range resolution is implemented by decreasing range cell size, then range resolution is improved, but range migration worsens as the peak response straddles more range cells
Solution Approach 1:
The patent applies the Keystone Transform to resample radar signals in the time-frequency domain, effectively adding a dimensional transformation that corrects range migration. By transforming the signal representation and resampling in a different domain (time-frequency), the patent resolves the contradiction between high range resolution and reliable Doppler integration without sacrificing either property.
2Measurement precision
If LFM is used for high range resolution, then range resolution is improved, but range migration occurs at high relative speeds causing peak response to straddle multiple range cells
Solution Approach 1:
The patent applies the Keystone Transform as a preliminary correction step before Doppler processing. By resampling the LFM signals in the time-frequency domain beforehand, the patent prevents range migration from occurring during subsequent processing, making the range peak position easily detectable even at high relative speeds.
3Measurement precision
If range cell size is decreased for high range resolution, then range resolution is improved, but the number of range cells increases causing the peak to straddle more cells
Solution Approach 1:
The patent transforms the signal to the time-frequency domain and applies resampling in this transformed space. This dimensional change allows the system to maintain fine range cell sizing for high resolution while preventing the peak from straddling multiple cells through the Keystone Transform correction, thereby preserving Doppler coherent integration information.
Data Source
AI summary
Aspects of the disclosure are directed to apparatuses, systems and methods for radar processing. As may be implemented in accordance with one or more aspects herein, an apparatus may include receiver circuitry to receive and sample radar signals reflected from a target, and processing circuitry to carry out the following. Representations of the reflections are transformed into the time-frequency domain where they are oversampled. The oversampled representations of the reflections are inversely transformed to provide resampled reflections. Positional characteristics of the target may then be ascertained by constructing a range response characterizing the target based on the resampled reflections.