串口数据丢帧引起的雷达测试故障原因分析

Analysis of Radar Test Failure as a Result of Serial Data Frame Loss

为解决某雷达高度表试验过程中发生的动作高度测试异常故障,采用故障树分析法对雷达高度表和测试设备进行故障排查;经检测发现,测试设备上位机的串口通信卡接收下位机的数据中有几十帧数据帧出现CRC校验位错误,被应用程序丢弃;原因是下位机发出的数据信号存在一定程度的畸变,上位机串口通信卡的串口控制器芯片OX16PCI694适应性不足导致数据读取出错;而应用程序在健壮性设计上也存在缺陷,以数据帧数来计算时间及雷达动作高度,但丢弃数据帧时未作相应处理;采用兼容性好的串口控制器芯片16C554重新设计通信卡,在上位机与下位机通信协议中增加数据的帧序号;经试验验证故障定位正确,解决措施有效,

To solve the fault of abnormal height data in the process of testing a radar altimeter, used fault tree analysis method for trou- bleshooting of radar altimeter and test equipment. It is found that there were dozens of frame data CRC parity error when the serial port com- munication card of the host computer to receive the data of the lower machine, those data were discarded by the application. Those data sig- nal from the lower machine had certain distortion and were readed error by the host computer for the insufficient adaptability of the serial con troller chip OX16PCI694 used in the serial communication card. The application in robust design is also defective, which calculated the time and height data of radar by those data frames, without corresponding treatment when discard the error data frame. Communication card was designed perfect by using the serial controller chip 16C554 with good compatibility, and increased frame number in protocol data from the lower machine. The fault location and solution is correct , which had been verified by test.