Ground-Based Radar Blurring Mitigation via Velocity Thresholding
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Solution Overview
Problem
Conventional ground-based radar systems, particularly synthetic aperture radar (SAR) systems, suffer from blurring effects due to fast-moving targets, which cannot be fully mitigated by reducing scanning time without compromising image quality and energy levels.
Innovation Solution
A method that involves selecting a Pulse Repetition Frequency and radial velocity threshold to differentiate between stationary and fast-moving targets through Doppler processing, allowing for the removal of fast-moving target contributions from radar images, thereby forming clear images of stationary targets without reducing scanning time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If scanning time is reduced to mitigate blurring effect, then image quality deteriorates and total transmitted energy levels decrease
Solution Approach 1:
The patent extracts and removes the harmful blurring effect caused by fast-moving targets from the radar image through signal processing. By identifying and eliminating the velocity components associated with moving targets, the system separates the desired stationary target information from the unwanted motion artifacts, thereby improving image quality without requiring shorter scan times
Solution Approach 2:
The patent changes the velocity parameter threshold to differentiate between stationary and moving targets. By applying a velocity threshold in the signal processing, the system identifies and removes components exceeding this threshold (fast-moving targets), thereby mitigating blurring effects while preserving image quality of stationary targets
2Object-affected harmful factors
If scanning time is reduced to mitigate blurring effect, then total transmitted energy levels must increase
Solution Approach 1:
The patent extracts and removes the harmful blurring effect caused by fast-moving targets from the radar image through signal processing. By identifying and eliminating the velocity components associated with moving targets, the system separates the desired stationary target information from the unwanted motion artifacts, thereby improving image quality without requiring shorter scan times
Solution Approach 2:
The patent changes the velocity parameter threshold to differentiate between stationary and moving targets. By applying a velocity threshold in the signal processing, the system identifies and removes components exceeding this threshold (fast-moving targets), thereby mitigating blurring effects while preserving image quality of stationary targets
3Object-affected harmful factors
If velocity threshold is increased to remove fast-moving targets, then tracking capability of fast-moving targets is lost
Solution Approach 1:
The patent segments the radar signal into two distinct components: stationary target signals and fast-moving target signals. By applying velocity thresholding, the system separates these components, allowing stationary targets to be imaged without blurring while simultaneously enabling separate tracking of fast-moving targets that would otherwise cause artifacts
Solution Approach 2:
The patent introduces velocity thresholding as an intermediary processing step between signal acquisition and image formation. This intermediary mechanism selectively processes different velocity components, allowing the system to eliminate blurring from stationary images while preserving and separately analyzing fast-moving target information
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
This approach effectively filters out the effects of moving targets, maintaining image quality and enabling the tracking of fast-moving targets while providing an alarm system for potential hazards, thus enhancing the capability to monitor both stationary and dynamic scenarios without increasing power consumption.
Implementation Method 1
radar antenna unit (20) and a radar sensor unit (30), the radar sensor unit configured to obtain respective range measurements and respective radial velocity measurements of the targets
Implementation Method 2
SAR focusing technique exploit Doppler principle: by measuring the relative radial speed vR between the moving sensor and a stationary target (2), as shown in FIG. 3, a target angular coordinate θ can be retrieved
Data Source
AI summary
In a method for mitigating the blurring effect in a radar image (40) obtained by a ground-based radar system, thereof, a Pulse Repetition Frequency (PRF) value is selected (110) in a radar sensor unit (30) such that radial velocity measurements of the targets of an observed scenario can be made up to a maximum unambiguous velocity vmax, a radial velocity threshold is also selected (101) to discriminate between substantially stationary targets and possible fast-moving targets having radial velocities vR, j≤v* and vR, f>v*, respectively. The scenario is conventionally scanned (120) by emitting transmission signals to the targets and receiving corresponding backscattered signals (23) from which raw data (25) are extracted (130), the latter in turn are Doppler-processed (140) so as to discriminate first and second data (31, 32) related to the substantially stationary and to the fast-moving target(s), respectively, according to whether the measured radial velocities (vR) are lower than the radial velocity threshold (v*) or not, respectively; second data are removed (150) from the Doppler-processed data (27) and radar image (40) is formed from remaining first data, i.e., based on the substantially stationary targets only. The method allows reducing the occurrence of artifacts due to fast-moving objects that are systematically present or that turn up in the scenario at the moment of taking an image thereof, such as truckloads or vehicle in general, as well as crane mobile portion in scenarios like a portion of a mine. (FIG. 11).