Radar Beam Response Spectrum Multi-Target Detection
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Solution Overview
Problem
Radar systems using constant false-alarm rate (CFAR) thresholds face challenges in accurately identifying multiple targets in a beam response spectrum, as these thresholds can lead to false identification of side lobes or exclusion of secondary targets due to angle-invariant settings.
Innovation Solution
A radar system and method that employs a threshold envelope varying as a function of angle of arrival, allowing for the detection of multiple targets by calculating and adjusting the threshold based on the maximum values and corresponding angles in the beam response spectrum, using techniques such as Gaussian smoothing and bias addition to enhance target detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant false-alarm rate (CFAR) threshold is applied to the beam response, then noise can be excluded from being mistaken for a target response, but side lobes of the beam response may be falsely identified as valid targets or secondary targets with power below the CFAR threshold may be excluded
Solution Approach 1:
The patent applies local quality by making the threshold angle-dependent rather than constant. The threshold envelope varies with angle of arrival, with different threshold values assigned to different angular regions. This allows the threshold to be locally optimized for each angle, preventing false identification of side lobes while maintaining noise exclusion capabilities.
Solution Approach 2:
The patent implements dynamics by transitioning from a static CFAR threshold to a dynamic threshold envelope that adapts to the beam response characteristics. The threshold envelope is constructed based on the actual beam response spectrum, making it adaptive to the specific detection scenario and enabling accurate identification of multiple targets at different power levels.
2Reliability
If a high CFAR threshold is set to exclude noise, then noise can be filtered out, but weaker reflections from secondary targets are also excluded
Solution Approach 1:
The threshold envelope provides different threshold levels for different angular regions. In regions where side lobes are present, the threshold is elevated to prevent false detection, while in regions where secondary targets may exist, the threshold is lowered to enable detection. This local differentiation allows simultaneous noise filtering and secondary target detection.
Solution Approach 2:
The patent changes the threshold parameter from a single constant value to a function of angle of arrival. This parameter transformation allows the threshold to vary continuously across the angular spectrum, enabling the system to maintain high thresholds in noisy regions while using lower thresholds in regions conducive to secondary target detection.
3Ease of operation
If an angle-invariant threshold is used, then the detection process is simple, but false identification of side lobes occurs
Solution Approach 1:
The patent replaces the uniform angle-invariant threshold with an angle-dependent threshold envelope. This local quality approach assigns different threshold values to different angular positions, allowing the system to account for the varying characteristics of the beam response across different angles and preventing false identification of side lobes.
Solution Approach 2:
The threshold envelope is pre-calculated based on the beam response characteristics before target detection is performed. This preliminary action of establishing the threshold envelope based on known beam patterns simplifies the detection process by providing ready-made angle-specific thresholds, eliminating the need for complex real-time adjustments while maintaining high detection accuracy.
Data Source
AI summary
A radar system may include a transmitter, a receiver, and a controller. The controller may calculate a received beam response spectrum based on the received reflected radar signal, detect a first maximum value of the received beam response spectrum, identify an angle corresponding to the first maximum value as a first target angle, obtain a threshold envelope based on the first maximum value and the first target angle, detect a second maximum value in a portion of the received beam response spectrum being greater than the threshold envelope, identify an angle corresponding to the second maximum value as a second target angle, and output the first target angle as the angle of arrival of the reflected radar signal from the first target and the second target angle as the angle of arrival of the reflected radar signal from the second target.