Bistatic SAR/GISAR/FISAR Geometry, Signal Models and Imaging Algorithms

5

Analytical Geometrical Determination of BSAR Resolution

In the bistatic synthetic aperture radar (BSAR) theory, three types of range resolutions can be defined: a generalized range resolution with respect to the bistatic angle’s bisector, range resolution on a target–receiver line of sight and range resolution along track of the target. The first two resolutions are relative, whereas the third is a certain resolution. The purpose of the study in this chapter is to reveal the time or spatial dependence of BSAR resolutions based on an analysis of the analytical expression for the range resolution derived by Willis [WIL 05].

5.1. Generalized BSAR range and Doppler resolution

5.1.1. BSAR range resolution

Consider a two-dimensional (2D) plane defined by a transmitter, pointlike target and receiver, described in the coordinate system Oxy (Figure 5.1), where A is the position of the transmitter, B is the position of the receiver and T is the position of the target. Denote AT = R_A and TB = R_B. The constant phase of the signal traveling from the transmitter through the target to the receiver is proportional to the constant sum of distances: transmitter–target and target–receiver, i.e.

[5.1]

where C is a constant whose value depends on the length of the transmitter–receiver line, baseline and the position of the target.

Expression [5.1] is an analytic geometric description of a geometric ...