Airborne Radar Clutter Masking for False Alarm Reduction
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Solution Overview
Problem
Airborne radars face desensitization in air/air and GMTI detection modes due to ground and sea clutter interference, leading to increased false alarms, computational load, and reduced detection of small targets with low Equivalent Radar Surface, as existing solutions either fail to effectively filter clutter or result in detection notches.
Innovation Solution
A method involving the creation of a distance-velocity mask in the radar reception chain to filter out echoes from secondary lobes, using antenna parameters and environmental context to assign binary values, rejecting echoes from the processing chain while maintaining detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the detection threshold is increased to filter ground and sea clutter echoes, then the false alarm rate is controlled, but the radar sensitivity is reduced and small targets with low SER cannot be detected
Solution Approach 1:
The detection space is segmented into multiple regions based on clutter characteristics. The mask divides the detection domain into clutter regions (where secondary echoes are expected) and non-clutter regions, allowing different detection thresholds to be applied to different segments. This enables maintaining high sensitivity in non-clutter regions while suppressing false alarms in clutter regions.
Solution Approach 2:
Different detection characteristics are applied to different spatial regions. The mask creates location-specific detection rules where clutter regions have higher thresholds and non-clutter regions have lower thresholds. This local differentiation allows the radar to maintain optimal sensitivity in clean regions while controlling false alarms in clutter-prone regions.
2Reliability
If the detection threshold is increased to stabilize the constant false alarm rate, then false alarms are controlled, but the detection of low SER targets is desensitized
Solution Approach 1:
The detection process is segmented into mask generation and filtered detection stages. The mask segments the detection domain based on predicted secondary echo locations, allowing the radar to maintain constant false alarm rate in clutter regions while preserving detection capability in non-clutter regions where the threshold remains optimized.
Solution Approach 2:
The harmful clutter echoes are extracted and isolated from the detection process through the mask. By identifying and excluding regions containing secondary echoes, the clutter interference is separated from legitimate targets, allowing detection to proceed with optimal sensitivity in clean regions without being constrained by clutter-induced false alarms.
3Reliability
If secondary echoes from clutter are filtered out to control false alarms, then false alarm rate is reduced, but computational load increases due to dummy tracking tracks
Solution Approach 1:
The mask is generated in advance based on predicted secondary echo locations, before the actual detection processing. This preliminary action identifies clutter regions ahead of time, allowing the radar to skip computational processing in these regions entirely, thereby reducing the computational load on tracking algorithms while maintaining false alarm control.
Solution Approach 2:
Dummy tracking tracks initiated by false detections are extracted and eliminated by the mask before they can consume computational resources. By pre-identifying clutter regions, the system prevents the formation of false tracks rather than having to process and then discard them, significantly reducing computational overhead.
4Reliability
If detection is deactivated over the entire speed domain of ground clutter to avoid false alarms, then false alarm rate is controlled, but a notch is created in the detected speeds axis
Solution Approach 1:
Instead of applying a uniform detection deactivation across the entire clutter speed domain, the mask applies localized suppression only to specific regions where secondary echoes are predicted. This preserves detection coverage in other speed domains while still controlling false alarms in the relevant clutter regions, avoiding the creation of broad notches in the speed spectrum.
Solution Approach 2:
The speed domain is segmented into regions affected by secondary echoes and regions that are not affected. The mask selectively applies detection suppression only to the affected segments, allowing targets in unaffected speed domains to be detected normally. This prevents the creation of unnecessary notches while maintaining false alarm control where needed.
Data Source
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AI summary
Since the echoes are captured in the range-velocity domain, the process is characterized in that it comprises: - a step of creating a mask (21), in the range-velocity plane, covering the detection zone of the echoes of ground clutter and/or sea captured by said secondary lobes, said zone being determinable by the antenna parameters of said radar, the waveform emitted by said radar and the environmental context of said radar, all points of said range-velocity plane covered by said mask being affected by a characteristic specific to said mask; - a step of filtering the received echoes in which the echoes covered by said mask (21) are rejected from the radar reception processing.