To solve the problem of spectral efficiency and energy efficiency of hybrid precoding in millimeter-wave communication system. This paper considers alternately using the minimization framework to increase beamforming gain. However, such framework because the radio frequency domain phase modulation network are using phase shifters, which result in non-convex constraints, and known solutions suffer from high computational complexity. Before using the alternate minimization architecture, it is proved that the phase angle of the ordered right singular vector of the channel matrix can be used to initialize the analog precoder, and hence, the complicated optimization procedures used to search the near-optimum analog precoding matrix can be avoided. In addition, the antenna array response vectors at the transmitter are not required. The simulation results show that the performance of the proposed algorithm is better than the traditional partial-connected algorithm and the complexity is lower, especially in the case of high signal-to-noise ratio.

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The large array multichannel detector itself has the problems of inconsistent dark current and uneven response between various channels, and after geometric splicing, the image output uniformity between multiple detectors is lower, which is difficult to meet the requirements of further image processing such as target recognition, early warning, tracking, prospection and so on. This paper researches the output image uniformity of multichannel large array detectors after splicing based on the integrating sphere radiometric calibration system, aiming at the problems of high difficulty in real-time imaging correction of space multichannel large array camera and the storage capacity of correction coefficient per pixel limited by hardware, a multichannel large array image uniformity adjustment approach applied to space camera is proposed. Firstly, the dark current correction is carried out to make the detector response consistent under the condition of full darkness. Then the edges of image points in adjacent boundary regions are fitted, and the correction coefficient is obtained. Finally, the correction coefficient is modified according to the saturation value of detector response. This approach significantly improves the uniformity and continuity of large array multichannel spatial remote sensing camera images, which provides the basic guarantee for subsequent image processing such as target recognition and tracking to improve the sensitivity and reduce the false alarm rate. This approach has few correction coefficients, small storage capacity and low hardware implementation difficulty. It has important reference significance for improving output uniformity of stitched focal plane images of large field of view space remote sensing cameras.