Synthetic-Aperture Radar Based on Nonsinusoidal Functions: X-Array Gain, Planar Arrays, Multiple Signals

Beam forming based on a line array of sensors and radio signals with a triangular autocorrelation function was discussed in Part IX of this series. The resolution angle e was shown to vary like 1/¿P/PN with the signal-to-noise ratio P/PN, which puts a premium on getting the best possible signal-to-noise ratio. This paper shows that the signal-to-noise ratio holding for one sensor can be replaced by the signal-to-noise ratio holding for the whole array, which usually is referred to as making use of the array gain. The result is generalized from the one-dimensional line array to the two-dimensional planar array. Furthermore, the method of beam forming is extended from signals returned by point-like scatterers or reflectors to structures composed of several point-like scatterers; the utilization of the array gain has not yet been investigated for this case.