In order to improve the performance of the ISAR imaging method based on compressed sensing under sub-sampling and low SNR

a new high resolution ISAR imaging method for chirp frequency stepped signal is proposed

based on the unique characteristics of the stepped frequency waveform

and the two-dimensional sparse structure information of the target. The proposed method is deal with the cross range focusing first and then the range resolution. Firstly

the pulse compression is performed on the sub-pulse echo

and then based on the analysis of the sparse structure of the stepped frequency ISAR echo in cross range dimension

a distributed compressed sensing model is constructed; Secondly

the DCS-SOMP algorithm is used to reconstruct the model

then the high cross range resolution imaging in low SNR is obtained; Finally

an arbitrary sparse representation model is constructed by using the echo characteristics in range dimension. Because the proposed method

which is cross range focusing first and then the range resolution

makes full use of the target structure

it not only avoids the migration through range resolution cell effect on the cross range resolution

but also has strong anti-noise performance

high reconstruction accuracy and low sampling rate. The validity of the proposed method is verified by simulation and experimental data.