Implementation Of Multi-channel CAN Data Acquisition In Inertial Navigation Test

In the calibration and reception of inertial navigation products,how to improve equipment utilization and reduce testing costs is one of the urgent problems to be solved.However,the CAN interface data acquisition device currently on the market can only collect up to eight channels of data simultaneously.Therefore,in order to further improve the efficiency of inertial navigation test and reduce the product development cycle of products,this paper designs an efficient and convenient 24-channel CAN data acquisition device.In this paper,the efficiency of FCFS scheduling algorithm in traditional digital multiplexing is not high enough,only takes into account the waiting time of tasks,not the execution time of the tasks,and easily causes the task to exceed the deadline.In this paper,we studied the dynamic value density and execution urgencies of task,designed a new dynamic priority allocation strategy(DPA).Proposed the DRTP task scheduling algorithm based on the DPA strategy.The DRTP algorithm analyzes the thrashing in the task scheduling process and sets the preemption threshold,which effectively avoids system thrashing.The experimental results show that compared with several classical algorithms,the DRTP algorithm can increase the system value gain,and significantly reduce the deadline miss rate and the number preemptions.Based on the hardware platform of FPGA,designed the CAN data receiving module,data verification module,DRTP-based digital multiplexing module and USB data transmission control module,24 channels CAN interfaces data multipled into a high-speed data frame through the cooperation of these modules,The CAN interface data is multiplexed into one high-speed data frame,and then the combined high-data frames are uploaded to the upper computer for storage and display through the USB3.0 interface chip.The modules in the FPGA are described by VerilogHDL language.The USB interface chip runs the firmware program of SlaveFIFO mode designed by C language.The upper computer compiles a multi-process inertial navigation test program based on shared memory mode in C#language,which can run steadily for a long time in the inertial navigation product test.In order to verify the function of the designed system,built test platform to test the basic functions of each component.In order to verify the function of the data acquisition system,designed an m-sequence generator in the FPGA,and designed a bit error rate test program in the upper computer,through data acquisition and comparison,analyzed the result,which shows the bit error rate of the system reached 10-10,it can meets the requirements of multi-channel inertial navigation test.The multi-channel CAN data acquisition device designed in this paper realizes the acquisition of multi-channel CAN data and has the characteristics of high stability and portability.It can significantly improve the efficiency of inertial navigation test and reduce the cost of testing.