Iterative noncoherent angular superresolution [radar]

In noncoherent scanning or imaging sensors, the angular resolution, θ, is limited by the aperture size, D, to the value θ∞λ/D, where λ is the wavelength. A method is proposed for improving the effective angular resolution by three to eight times by postdetection processing of the aperture-limited signal. The technique derives from modeling the detected signal as the desired high-resolution equivalent signal degraded by convolution with the antenna pattern or point-spread function of the physical sensor. The resolution is therefore increased by deconvolving the real-aperture data. This deconvolution, or inverse filtering, approach is inherently numerically unstable. A constrained iterative deconvolution algorithm was adapted to obtain well-behaved results exhibiting true superresolution, and a fast algorithm was developed to overcome the computational burden of the iterative approach. Examples using both simulated and real millimeter-wave radar data is shown