| 主权项 |
1. A bistatic synthetic aperture radar (SAR) imaging method, the method comprising:
receiving a plurality of radar return pulses acquired by at least first and second airborne radar platforms, wherein each radar return pulse is generated in response to a corresponding transmission pulse reflected from two or more radar scattering locations on a target; combining each radar return pulse with a sinusoid to reduce the radar return pulses to a base band frequency; deskewing each reduced radar return pulse to remove effects of its corresponding radar transmission pulse; estimating motion parameters of the target based on a maximum likelihood estimation (MLE) applied to the deskewed radar return pulses; performing MLE motion correction to the deskewed radar return pulses based on the estimated motion parameters to generate motion corrected radar return pulses; acquiring position and velocity estimates of the two or more airborne radar platforms and the one or more scattering locations on the target; defining bistatic range and velocity vectors based on the position and velocity estimates of the first and second airborne radar platforms, the one or more scattering locations on the target, and the motion corrected radar return pulses; defining new bistatic range and velocity vectors by redefining the bistatic range and velocity vectors in a new set of orthogonal axes; projecting vector distance differences between the target radar scattering locations along the new set of orthogonal axes to generate new range and velocity measurements along the new set of orthogonal axes; converting the new range and velocity measurements in order to map Doppler frequency into cross-range, measured in physical units of length; and forming a bistatic SAR image in range and cross-range based on cross-range extent derived from the Doppler frequency mapping. |
