Coherent aperture synthesis for incoherent source

Abstract

We propose a refinement of the method for aperture synthesis for an incoherent source, imparting selectivity and noise immunity to the method. Instead of measuring the phase difference between the signals of the array receivers, we measure the array-averaged phase difference between neighboring receivers by searching for the maximum of the magnitude of the moving array’s response to the source signal during its direction-of-arrival-scanning (phasing). This procedure is carried out after incoherent accumulation. The gain in noise immunity is determined by the gain in the array with the addition of the gain in incoherent accumulation. The size of this gain in the experiment was on the order of 20 dB. The method retains applicability to wideband signals and the possibility of observing other incoherent signals. We demonstrate the possibility of high angular resolution with the synthesized antenna of the source, which does not possess the perfect time coherency of the source and other sources coherent with it. Owing to phase averaging over the array aperture, we obtain an increase in the method’s stability to reverberation. We present results of simulation and applicability of the method in full-scale experiments.