Development of vehicular embedded information processing system for map-based precision farming

Abstract: In order to meet needs of information acquisition and processing of map-based intelligent precision farming machinery, a vehicular embedded information processing system was developed. Based on an embedded GIS and an ARM(Adanced RISC Machines)-based industrial control subsystem, the system integrated a DGPS (differential global positioning system) subsystem and a detection device monitoring traveling speed of the farming machinery. The ARM-based industrial control subsystem was composed of an EPCS-8980 typed ARM IPC (Guangzhou Zhiyuan Electronic Co., Ltd, China) and a liquid crystal display touch screen. The ARM IPC had a strong ability to process information with a XScaleTMPXA270 (Intel company, the United States) CPU and a basic frequency of 416 MHz. Based on eSupermap 6.0, the embedded GIS was developed and operated on Windows CE 5.0 in the ARM-based industrial control subsystem. The DGPS subsystem consisted of a G12-B typed DGPS reference station (Beijing Wintek Technology Development Co.,Ltd, China), a SX-2A typed DGPS mobile module (Hemisphere GPS Company, Canada) and 2 broadcasting stations, could realize a real-time positioning accuracy of sub-meter. The detection device of traveling speed consisted of a iCAN-7202 frequency measuring module (Guangzhou Zhiyuan Electronic Co., Ltd, China) and a JK8002C Hall typed proximity sensor (Nanjing camellia electronic Co., Ltd, China), measured the instantaneous traveling speed by monitoring rotating speed of the wheel. The system received farmland information from the farmland information acquisition module through CAN bus with iCAN protocol, integrated it with the dynamic GPS location information received from the DGPS subsystem by RS-232 interface, generated farmland information distribution map in the embedded GIS by means of grid dividing and attribute editing, and output it via USB interface. The distribution map was on *.pmw format. But the crop management decision system couldn't access files with this format. So format transformation from *.pmw to *.shp was carried out on off-line computer by the eSuperMapViewer and eSmTranslator software. Working prescription map was generated by the crop management decision system with a format of *.shp on the off-line computer, and transformed into *.pmw format with the eSuperMapViewer and eSmTranslator software. The system input working prescription map via USB interface, integrated it with the dynamic GPS location information, interpreted it with the embedded GIS by coordinate matching and grid identification, and output the farming control command to variable rate farming controller through CAN bus with the iCAN protocol. Field simulation test results showed that the system operated very well, it generated farmland information distribution map and interpreted working prescription map correctly, measuring absolute error of the traveling speed was within 0.1 km/h, the maximum delay time of prescription map interpretation was less than 1 s, grid identification error was within -0.5-0.6 m with a 3 km/h traveling speed.