Azimuth compression can then be conducted along each parallel azimuth line
Though the PSD of a single azimuth line
(within the same range gate) is very noisy and can not hold the attenuation property, the expected PSD [mathematical expression not reproducible] can hold the property for most ground scenes, where E(*) indicates the expectation value.
Here [I.sub.SL] (t, [t.sub.L]) is the azimuth line
of the SAR look with the index L, L = 0, [+ or -] 1, [+ or -] 2, ..., [+ or -] [N.sub.L]/2, where [N.sub.L] is the number of looks (an odd number).
As illustrated in Figure 5(a) and Figure 5(b), three lines stand for time-frequency graphs of three targets in one azimuth line, and the whole Doppler frequency bandwidth [B.sub.a] of the raw data is larger than PRF.
After the range compression, a range inverse FFT takes the data to range-Doppler domain, where each azimuth line is multiplied by an azimuth compensation phase function.
In order to analyze the tomographic estimates in detail, the estimates along four azimuth lines are plotted in Figure 5, respectively.
In order to analyze the tomographic result in detail, the estimated targets along two azimuth lines are plotted in Figures 7(b) and 7(c).