Application Of Hardware-based Kalman Filter To Improve The Precision Of Real-time Femtosecond Laser Absolute Ranging

The satellite formation flying is the background of the research in the article.The satellite formation flying requires the satellites to achieve high precision,high update rate real-time absolute ranging,but the methods of traditional laser ranging can not satisfy the large ranging scale and real-time ranging with high precision.The application of femtosecond laser ranging finder provides the possibility of realizing high precision real-time ranging between satellites.Facing the demand of integrated,high precision and high update rate for double-combing absolute ranging finder equipped to the micro satellite platform,this artic designed a FPGA-based digital signal processing module with the Kalman filter algorithm embedded.The efficient hardware filtering algorithms contribute to the real-time distance measurement with high precision and help to the communication beteween the FPGA and satellite.The main work is as follows:1?In order to complete the high update rate and high precision distance calculation of the femtosecond laser ranging finder,FPGA logic chip was chosed and an high-speed digital signal acquisition circuit was designed to match the ALINX core board which was used to fininsh the signal processing.2?According to the control protocol of the femtosecond laser ranging finder,the FPGA-based data transmission control program,data verification program and serial transceiver program were prepared to achieve the information exchange between the femtosecond laser ranging finder and satellite platform through the serial communication to CAN bus module CSM100.3?In order to ensure the real-time distance update rate and reduce the uncertainty of the ranging results,a Kalman filter algorithm based on FPGA has been written.The hardware Kalman filter algorithm was fitted into the femtosecond laser ranging system,and the distance experiment was carried out at the cooperation target of 1.5 m.The standard deviation of the ranging was 1.47?m at the update rate of 1.5 kHz.The ranging finder accurately resolved and updated the target distance when the target was moving at a 20 ?m step size.In summary,the article mainly studied the FPGA-based Kalman filter program.With the femtosecond laser ranging finder integrated and portable,the high precision and high update rate absolute distance measurement between micro satellites was realized.Meanwhile,the FPGA-based data transmission control module helped to achieve real-time control from the satellites to the femtosecond ranging finder equipment.The high-speed digital signal acquisition circuit has been designed during the period.