Abstract:  The principle of rendezvous and docking image (RVD) sensor is introduced. The measure system of onetarget RVD image sensor with image track windows is presented. Without any change in the hardware of the sensor, four improvements of embedded software are brought to multitarget RVD image sensor, such as multitarget calculating track windows, multitarget prediction of image row windows, multitarget image match and multitarget results optimization. The safety level ascends when the measure system becomes multispare mode. The automatic switch within different targets improves the process of RVD. The independence level is greatly improved while the switch of different camera is replaced by different spots in images from one camera. The improvements are already used in many missions of RVD in China.