Sparse-Array Radar Angle Estimation With Coherent Signal Processing

The patent segments the signal processing into multiple hypothesis tests, where each hypothesis corresponds to a potential target angle. By dividing the angular space into discrete hypotheses and testing each independently, the system resolves the ambiguity that arises from sparse antenna configurations while maintaining large coverage area.

The patent changes the processing parameter from direct phase shift compensation to hypothesis-based angle estimation. Instead of attempting to compensate for phase shifts in a continuous manner, the system discretizes the angular parameter into multiple hypotheses, transforming the measurement problem into a selection problem among discrete angular candidates.

The patent merges signals from multiple receiving antennas for each hypothesis by coherently combining the received signals. This combining process improves the signal-to-noise ratio through constructive interference of the target signal while noise components tend to cancel out, enabling reliable detection at extended ranges despite the sparse antenna configuration.

The patent skips the intermediate step of full phase calibration and direct signal combination by rushing through to hypothesis-based processing. Instead of meticulously calibrating each antenna's phase response, the system directly tests multiple angular hypotheses and selects the best match, thereby achieving range extension without the complexity of precise phase calibration.

The patent performs preliminary action by pre-defining multiple angular hypotheses before signal processing. These hypotheses represent potential target directions and are prepared in advance as discrete angle candidates. During processing, the system simply evaluates which pre-defined hypothesis best matches the received signals, avoiding the need for complex continuous optimization while achieving high angular resolution.

The patent uses computationally inexpensive hypothesis tests that can be quickly evaluated and discarded. Each hypothesis represents a simple angular candidate that can be tested with basic signal correlation, and after evaluation, each hypothesis is discarded in favor of the next candidate. This approach replaces complex iterative optimization with multiple simple, disposable evaluations.

The patent changes the measurement parameter from continuous phase-based angle estimation to discrete hypothesis-based angle selection. This parameter change allows the system to achieve accurate angular measurements with fewer antennas by transforming the measurement problem into a multiple-choice question among pre-defined angular hypotheses, rather than requiring precise phase measurements from many antennas.

The patent introduces angular hypotheses as an intermediary between the received signals and the final angle measurement. These hypotheses act as mediators that bridge the gap between limited antenna measurements and accurate angle estimation, allowing the system to achieve high measurement precision with reduced hardware complexity by using the hypothesis layer as an intermediate processing stage.