Fig.1

In orbit spacecraft coordinate system"

Fig.2

Definition of attitude angle of spacecraft in orbit"

Fig.3

ISAR equivalent imaging plane of attitude stabilized spacecraft"

Fig.4

Unet3+network model"

Fig.5

ISAR images of spacecraft measured by Germany TIRA radar"

Fig.6

Flowchart of the proposed algorithm"

Fig.7

Three-dimensional distribution of point model"

Fig.8

ISAR image, scattering center and projection image of point model"

Fig.9

Variation curve of LOS in orbital coordinate system"

Table 1

Average value of the angle between the normal vectors of plane A and B"

Fig.10

Maximum angle between normal vectors of plane A and B with different orbital parameters"

Fig.11

Linear structure model of Chinese space station"

Fig.12

Typical ISAR images, component segmentation and linear structure of Chinese space station"

Table 2

Size and orientation of typical ISAR image components of Chinese space station"

Table 3

Average error of linear structure components for test"

Fig.13

Error curves of three kinds of linear structure vector attitude estimation"

Table 4

Average attitude angle error ϕ of three linear structure vectors"

Table 5

Average attitude angle error ϕ of three linear structure directions"

Fig.14

Error curves of orientation and attitude estimation of three linear structures"