Research on the redundancy characteristics of the LASMR-COSM instrument

L band aperture synthesis microwave Radiometer (LASMR) on board Chinese Ocean Salinity Mission(COSM) is a two-dimensional interferometer, which, due to the Fourier-transform relationship between the spatial domain and the brightness temperature, possesses a well-behaved redundancy characteristic. The analysis results show that when the failed units are located on long baselines, the more units that fail, the greater the decrease in system resolution, while if the failed units are on short baselines, the impact on system resolution is relatively minor. LASMR improves resolution by synthesizing the aperture but worsens sensitivity, hence when there are unit failures, the system’s noise floor is reduced in most cases, showing a trend towards optimization. The absence of long and medium baselines has a minor impact on the quality of the brightness temperature image, while the lack of short baselines significantly affects the image quality, leading to a rapid deterioration in image accuracy. However, under fixed unit failure conditions, the impact on images for different targets is biased in effect. The error correction of the brightness temperature can be performed using the ocean target transform (OTT) technique, and the image accuracy is significantly improved. Even under the adverse condition of 15 unit failures, the image accuracy can still reach 0.12K. The redundancy characteristics of the LASMR are evident.