Design And Implementation Of Pipeline Surveying Instrument Based On Inertial Measurement

Aiming at the need of improving the geographic information system of underground pipelines in major cities,a surveying instrument used for underground deep buried and nonmetallic pipeline measurement is developed.The instrument takes the micromechanical inertial measurement unit(MEMS-IMU)and odometer as the measuring element,based on MEMSIMU/ odometer dead reckoning algorithm as the core algorithm,supplemented by all kinds of instrument compensation algorithm,realizes pipeline trajectory measurement through pulling and walking in the pipeline.The main work of this thesis includes:1.The basic principle of inertial measurement is introduced,and the overall design of the trajectory detection scheme for underground pipeline is made,including the mechanical structure,the data acquisition system and the data processing system.2.The data acquisition system is divided into two parts: the hardware circuit and the acquisition program.The data acquisition system is responsible for collecting the data of MEMS-IMU and two odometer.The data is stored in the SD card,and the data will be uploaded to the computer through the USB interface after the end of the measure.The hardware circuit consists of key and display circuit,RS232 transfer circuit,Holzer pulse input circuit,STM32 minimum system,JTAG interface circuit,USB interface circuit,SD card interface circuit and power module.The acquisition program runs in the MCU STM32F103RCT6,including serial communication,external counting,message splicing,DMA memory transmission,ping-pong buffer storage,SPI communication,file system and USB communication.3.The data processing system is divided into message analysis,sensor error compensation,navigation calculation/information fusion,dead reckoning and trajectory plotting.The navigation calculation/information fusion module uses complementary filters and extended Kalman filters to fuse data from gyroscopes,accelerometer and magnetometer to obtain high precision real time attitude.The dead reckoning achieved by combining real-time attitude angle with distance information provided by odometer.The trajectory plotting module is used to draw the trajectory of the pipeline.At the same time,by using the position of entry/exit,the track is stretched and rotated to improve the precision of trajectory.5.The feasibility of the underground pipeline trajectory detection system developed in this paper is verified by the trolley simulation experiment and the actual measurement,which meets the requirements of the CJJ61-2003.