基于地面发射机的方位多通道SAR系统通道幅相误差估计方法

方位多通道SAR系统能够克服最小天线面积的限制，从而满足了高分辨率和宽测绘带的性能要求，是星载SAR研究的热点。对于方位多通道SAR系统，通道间的幅相误差对系统成像性能有很大影响，必须对其进行标定。针对幅相误差具有空变性和估计精度易受噪声影响的特点，利用子空间投影算法，提出了一种基于地面发射机的定标方法，通过合理的地面发射机布设策略，解决幅相误差空变特性估计的问题，通过地面发射机容易实现高信噪比的特点，抑制噪声对估计精度的影响。最后通过仿真实验，对提出方法的有效性和精度进行了仿真验证，实验表明，该方法可以通过布设少量地面接收机即可解决幅相误差估计中空变特性和噪声影响的问题，同时还降低了算法的运算量，在仿真中达到了良好的估计精度，实现了成像的校正。

Method of gain phase error estimation for azimuth multi channel spaceborne SAR system based on transmitter on the ground

Azimuth multi channel spaceborne SAR system are able to overcome the limitation of minimum antenna constraint, so that it can yield high resolution and wide swath (HRWS) images. For this reason, this system is becoming research hotspots now. For azimuth multi channel spaceborne SAR system, gain phase errors between channels have a negative effect on the quality of imaging of system, so we must calibrate those errors. For range variant characteristics of phase error and negative effect on estimation caused by noise, utilizing Signal Subspace Comparison algorithm, we put forward a method of gain phase error estimation based on transmitter on the ground. Through suitable disposition oftransmitter,we can overcome range variant characteristics of phase error. Through controlling the power of transmitter, we can restrain the negative effect on estimation caused by noise. Finally, we validate it through simulation. It shows that we can solve the problem caused by range variant characteristics of phase error and the effect of noise by using a few transmitter. At the same time, in this way we can guarantee the precision of algorithm and it can also abates the amount of calculation.