RLG position and orientation system used for motion compensation in airborne InSAR

Position and orientation system (POS) is the key equipment for improving the image resolution of synthetic aperture radar (SAR). According to the motion compensation requirement of SAR, the size effect of dither ring laser gyroscope (RLG) inertial measurement unit (IMU) was analyzed. A small size structure of inertial sensitive assemble with eight absorbers was designed. Based on the DSP+FPGA hardware scheme, a data collecting and preprocessing module was designed. Based on digital filter model, a time-delay compensation method was proposed. Finally, a small size high precision RLG POS was successfully developed. The experiment results show that the static inertial navigation error of RLG inertial system is 0.196 nmile/h. The inertial navigation errors are 0.659 nmile/h and 0.681 nmile/h for vehicle and airborne experiments, respectively. The developed RLG POS meets the requirements of improving SAR image resolution.