It can be viewed as a more general form of LBF than OLBF, ELBF and other recently proposed forms in [31-33].
Until now, we have mentioned five kinds of LBF: OLBF, ELBF, GLBF, ILBF and AILBF.
This condition can be viewed as a general necessary requirement which should be satisfied if the PTRSs of kind LBF, including the OLBF, ELBF and AILBF, can be applied to general bistatic cases.
In this section, we will compare the performance of OLBF, ELBF and AILBF.
Firstly, we compare the QPE of OLBF, ELBF and AILBF.
Secondly, we use the ideal numerical PTRS, OLBF, ELBF and AILBF as matched filters for the method of 2D frequency domain matching to focus the echo of a point target P(0,0).
From Table 3, it can be seen that for spaceborne/airborne forward-looking case, ELBF and AILBF both have a similar focusing ability with the ideal numerical spectrum.