Development and test of real-time monitoring system for soil wind erosion based on GPRS network

Abstract: In order to overcome the shortcomings and deficiencies of field observation and wind tunnel test, it needs to be improved for the continuity, scientificity and reliability of observation data to meet the demand of wind erosion monitoring in the field. In this paper, the wireless sensor network technology, sensor technology, electronic technology and network communication technology were used together to develop the wind speed profiler and the multi-channel sand sampler that had functions of wireless ad-hoc networks and automatic data acquisition and processing. Meanwhile, LabVIEW was used to design the client data processing software which could monitor six wind speed profile points and six wind sand flow structure points simultaneously. On this basis, a soil wind-erosion monitoring system using C/S framework was established, which realized the functions of automatic collecting, real-time processing and remote monitoring of the environment temperature, humidity, atmospheric pressure, wind speed profile and wind-sand distribution by means of GPRS wireless module and remote server. The test results showed that the time from power up to output stability would not exceed 8 s, and the wind speed response time was 2 to 3 s. The output voltage and wind speed satisfied polynomial fitting and monotonically increase. The measurement range was 0~17 m/s, and its measurement accuracy decreased with the increase of wind speed. The accuracy could reach 0.1 m/s at 6 m/s and 0.3 m/s at 17 m/s. The wind speed profiler realized the automatic acquisition, processing and wireless transmission of the environment temperature, humidity, atmospheric pressure and wind speeds at 2, 4, 8, 16, 24, 32, 48 and 64 cm heights. Besides, the speed-reduction efficiency and the wind-sand separation efficiency of the wind-sand separator were above 96% and 99.8%, respectively, and the average equidynamic performance was not less than 92%. The weighing system was in the range of 0 to 170 g with accuracy of 0.01 g. The short-term static error and long-term cumulative error were no more than ±0.02 g and ±0.04 g, respectively. The average sand collecting efficiency of the sand collector was 91.98%. The setup time of wireless communication was not more than 5 s, and the central node could achieve 1 time nodes traversal and data aggregation within 3 s. The effective transmission distance was more than 140 m. The maximum working time of the wind speed profiler node and the sand sampler node was not less than 6 h and 22 h, respectively. Under field tests, the stability and reliability of the system can be verified, data packet loss rate of the ad-hoc network and error packet number were also zero. The measured wind profiles and wind-sand distribution curves were in accordance with the exponential distribution law. The deviation of environmental temperature, relative humidity and atmospheric pressure were less than 2 ℃, 4% and 10 hPa, respectively. Therefore, the results could provide an effective research platform and important data support to meet the needs of large scale and cross-regional field synchronous study of soil wind erosion.