Principles of Modern Radar - Volume 2 1891121537

274 CHAPTER 7 Stripmap SARFIGURE 7-11DBS-AD is similarto DBS butpreprocesses thedata to DBS with adechirp stage.d(u, t)× e -jψ Chirp(u)d Dechirp (u, t)1-D FFT(u)D Dechirp (k u , t)Mappingf(x, r)The flow diagram for DBS with AD appears in the Figure 7-11 and differs from theDBS diagram in Figure 7-6 only in the addition of the dechirp stage. The compensateddata is denoted d Dechirp (u,t).The following simulation parameters were used to demonstrate the effect of thequadratic phase term and the benefit of AD to DBS:• Carrier frequency = 9.5 GHz• RF bandwidth = 15 MHz• Integration angle = 0.1 ◦• Resolution = 10 m (both dimensions)• Range to scene center = 50 km• Scene size = 1kmby1kmDiagrams of the collection geometry and the location of point targets are provided inFigure 7-12.−500Collection Geometry−500Scene Geometry−400−400−300−300−200−200Along-Track (m)−100010020050 km range toscene centerAlong-Track (m)−1000100200300400Aperturepositions300400Scene limits1 km by 1 km5000 1 2 3 4Cross-Track (m)(a)5 6× 10 4500−600 −400 −200 0 200 400 600Cross-Track (m)(b)FIGURE 7-12 Simulated DBS-AD geometry emphasizing (a) the overall collectiongeometry, and (b) point scatterer locations in the scene of interest.