Abstract: A signal processor eliminates sidelobe response from signals produced by a spaced antenna array that forms a single beam using spatial frequencies. The signal processor also produces error signals. The signal processor uses a phase coherent local oscillator to simultaneously convert the wavefront signal from each element of the antenna array to three different first intermediate frequency signals IF. The first IF signals of each element are cross-correlated with the first IF signals from each of the other array elements to form the signals containing sampled spatial frequency components IF.sub.2. Cross-correlating a second time using the sampled spatial frequencies as inputs produces signals containing derived spatial frequency components IF.sub.3. The signals containing derived spatial frequency components are synchronously detected (phase compared) and summed to provide a single beam output signal.

Abstract: An antenna array comprising at least three interferometer pairs of antenna elements with selected spacings made to form a single beam which is readily scannable. All spatial frequencies generated by a signal and intercepted by the array are derived from a signal processing technique applied to the array. The array samples space in the spatial frequency domain while the signal processing technique utilizes real time convolution of functions in the spectral frequency domain. Summation of the appropriate spatial frequencies is equivalent to a Fourier transform operation, yielding the location of the signal source in space. Resolution and freedom from interference of the interferometer system is equal to that of a fully filled array of the same aperture size containing element spacings of one-half wavelength.