The principle to form a synthetic array is through transmitting pulses at index times p and receiving the echo signals at each sensor element position a p =[0,p ΔA,hog]T, where hog is the height overground and ΔA denotes the advance per ping of the imaging platform. A typical geometrical setup of a synthetic aperture imaging system operating in stripmap mode is depicted in Figure1, where the direction of wave propagation and the traveling direction of the imaging platform are called range, x, and along-track, y, respectively.

A synthetic aperture radar (SAR) is an active sensor that first transmits microwave signals and then receives back the signals that are returned, or backscattered , from the Earth's surface. The instrument measures distances between the sensor and the point on the Earth's surface where the signal is backscattered.