ISAR中解线频调回波相干化的研究

提出了一种对固定参考距离的dechirp回波进行降频和相位补偿处理,使之等效于变参考距离的dechirp回波数据,从而将ISAR中的dechirp回波相干化的方法.用此方法可以大大加快成像速度,并且对低信噪比条件下的ISAR成像非常有益.

A Method to Make ISAR Echoes Coherent in a Non-Coherent Dechirp System

For the sampling bandwidth to be reduced, ISAR echoe s are usually dechirped at the receiver with the reference range varying according to the target position at each pulse. Thus, the echoes are non-coherent after dechirping. A remedial method is presented by reducing the frequency and compens ating the phase of the echoes whose reference ranges are unchanged, so as to mak e them be equivalent to the echoes which are dechirped by variable reference sig nal. As a result, we can obtain the variable reference precisely and with this c ondition a group of sampled target echoes can be made coherent. This method will improve ISAR imaging speed greatly and be of special value in ISAR imaging when signal to noise ratio becomes low.