Radar Signal Processing Mask for Coastal Clutter Suppression
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Solution Overview
Problem
In land/sea detection mode, scanning radar systems face high rates of false alarms due to earth surface interference, leading to decreased detection probability of small targets on water surfaces and increased computational load, especially near coastal areas.
Innovation Solution
The method involves using a digital terrain model (DTM) to create masks that differentiate between land and sea surfaces, applied before detection processing, allowing for a lower detection threshold and reducing false alarms while maintaining sensitivity for sea surface targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the detection threshold is raised to reduce false alarms from land clutter, then the false alarm rate decreases, but the detection probability of small targets on the sea surface decreases
Solution Approach 1:
The observation area is segmented into land and sea regions using a digital terrain model. Different detection thresholds are applied to each segment: a higher threshold for land areas to suppress clutter false alarms, and a lower threshold for sea areas to maintain sensitivity for small target detection. This spatial segmentation resolves the contradiction by allowing threshold optimization for each specific environment.
Solution Approach 2:
The detection threshold is made local rather than global. The system dynamically adjusts the threshold based on the local terrain type (land or sea) identified from the digital terrain model. This allows the threshold to have different values in different spatial locations, simultaneously reducing false alarms over land and maintaining detection sensitivity over the sea.
2Reliability
If the detection threshold is raised to suppress land clutter echoes, then false alarms decrease, but the computational load for processing all detections increases due to more detections to track
Solution Approach 1:
The system segments the detection space using land/sea masks derived from the digital terrain model. By restricting detailed processing to only sea-area detections, it reduces the total number of detections requiring tracking and analysis, thereby lowering computational load while maintaining reliable false alarm suppression over land areas.
3Ease of operation
If a single detection threshold is used for the entire observation area, then the system is simple to operate, but it cannot simultaneously optimize for both land and sea detection performance
Solution Approach 1:
The system automatically determines the appropriate detection threshold for each location based on the digital terrain model data, without requiring manual configuration or user intervention. The land/sea masks and threshold calculation are performed automatically, maintaining ease of operation while achieving adaptability to different surface types.
Solution Approach 2:
The detection threshold parameter is dynamically changed based on the observed terrain type. The system automatically adjusts the threshold value according to whether the radar is observing land or sea areas, allowing optimal detection performance for each surface type without manual parameter tuning.
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 reduces false alarms, improves tactical clarity, and lowers computational complexity by filtering out earth surface echoes, enabling effective detection of small targets on the sea surface near coastlines.
Implementation Method 1
The field of the invention is that of methods for processing the signal of a scanning radar in land/sea detection mode
Implementation Method 2
These obstacles send an echo back to the radar
Implementation Method 3
a fast Fourier transform FFT can be applied, according to the dimension in recurrence, to the samples distance / recurrence E(d, rec), so as to sample the signal S(t) along a dimension corresponding to Doppler frequency information Δ f
Data Source
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AI summary
A method (100; 200) for digital signal processing (S(t)) of a pulse and scanning radar during an observation of a coastal zone in land/sea detection mode, the signal being sampled according to a two-dimensional temporal map, a distance dimension (d) and a recurrence dimension (rec), comprising: the selection of a digital terrain model file (MNT) of the observed coastal zone; transformation (110; 210) of the temporal map and/or of the digital terrain model file to obtain a transformed temporal map and/or a transformed digital terrain model file the data of which are expressed in a common reference frame; construction (120) of a mask (MT; MF) from the transformed digital terrain model file; and, application (130) of the mask to the samples (E(d, rec); E(d, Af)) of the map associated with the transformed temporal map, in such a way as to obtain filtered samples (Ef(d, rec); Ef(d, Δf)).