Research And Implementation Of Locating System For Facility Agricultural Vehicle Based On Zigbee

Facility agriculture is one of the main production mode in modern agriculture.The implementation of precision agriculture is an important way to improve the level of agricultural modernization in the facility agriculture environment.And improving the intelligent level of facility agriculture equipment plays an important role in promoting the implementation of precision agriculture operation in facility agriculture.The autonomous locating technology is one of the key technology to facility agriculture intelligent equipment.Foreign high precision agricultural equipment locating system is expensive,which is not suitable for widely use in China's rural areas.And its core technology is not open to the outside world.Therefore,it is of great significance and value to study the agricultural location system which is suitable for China's agricultural production and has independent intellectual property rights.Some problems of facility agriculture vehicle locating system still exist now,such as low locating accuracy and high cost.In order to solve these problems,the locating principle based on RSSI is used as the basic technology of locating system in this paper.And the least square method is used to solve the defect of the trilateration algorithm.Besides,an improved locating algorithm based on internal reference point error feedback weighted compensation model is proposed.The algorithm is simulated with different distribution mode and different number of error compensation reference point.The ZigBee module based on CC2530 is used as the hardware foundation of the facility agricultural vehicle location system in this paper.The hardware structure for gateway node,reference node and mobile node was designed.And the program for locating system on chip was developed.The monitoring software of the upper computer for the locating system was developed with using Basic Visual.The platform of facility agriculture vehicle locating system was completed.The locating system was measured and analyzed in the open outdoor and Venlo type glass greenhouse.Firstly,the influence of different antenna heights on the RSSI value is measured and analyzed,and the suitable antenna height is determined.Secondly,the measurement data at the suitable antenna height were fitted to obtain the specific path loss attenuation model under the specific environment by using MATLAB.Finally,the model was used for test and analysis.Outdoor contrast test at the range of 20 meters by 20 meters was carried out with three groups,namely four error compensation reference points in the internal area,four error compensation for compensating reference points at the boundary and eight error compensation reference point in the internal area.The results of the tests show that three kinds of error compensation methods are able to reduce the locating error effectively,and the four error compensation reference point in the internal area has the lowest average locating error.In addition,outdoor test at the range of 10 meters by 10 meters and greenhouse test at the range of 6 meters by 8 meters were carried out with four error compensation reference points in the internal area.The results of the tests show that the location algorithm based on the internal reference point error feedback weighted compensation model can effectively reduce the average locating error and improve the locating accuracy,which provides a reference for further research about the precise locating system of facility agriculture vehicles.