12.3. A side looking SAR takes on eight positions within an observation interval. In each position the radar transmits and receives one pulse. Let the distance between any two consecutive antenna positions be , and define to be the one-way phase difference for a beam steered at angle .

(a) In each of the eight positions a sample of the phase pattern is obtained after heterodyning. List the phase samples.

(b) How will you process the sequence of samples using an FFT (do not forget windowing)?

(c) Give a formula for the angle between the grating lobes.