Fig.1

Geometry diagram of strip SAR imaging"

Fig.2

Schematic diagram of the circumferential spotlight mode"

Fig.3

Relationship between fc and Fs in the ViSAR system"

Fig.4

Atmospheric attenuation curves with different frequency bands"

Fig.5

Aperture overlap model"

Fig.6

Schematic diagram of the principle of moving target shadow formation"

Fig.7

ViSAR system imaging results released by SNL"

Fig.8

Imaging results of DRDC's ViSAR system"

Fig.9

Schematic diagram of ViSAR's system structure and imaging results developed by DARPA"

Table 1

Relevant parameters of high-frequency and non-high-frequency ViSAR systems"

Fig.10

Hardware and imaging result of the new MIRANDA-300"

Table 2

Research progress of foreign ViSAR system"

Fig.11

Block diagram of FMCW-SAR system"

Fig.12

FMCW-SAR system and its imaging result"

Fig.13

Diagram of high-frequency ViSAR system in [50]"

Fig.14

Actual board of ViSAR digital processing component"

Table 3

Research progress of domestic ViSAR"

Fig.15

Instructions for iterative FBP algorithm"

Fig.16

Comparison of imaging results"

Fig.17

Results of coherent summing of continuous sub-apertures"

Fig.18

Comparison of BP imaging with weighting sub-aperture combination methods"

Fig.19

PFA process of ViSAR imaging"

Table 4

Comparison of detection performance 个"

Fig.20

Flowchart of the improved Faster R-CNN algorithm"