农田作业机械测速方法试验

实时对地速度测量是精准农业智能装备必备的一项功能。该研究的目的是评价不同农田作业机械地速测量传感器的性能情况，选用多普勒雷达、霍尔元件、RTK-GPS、RTD-GPS和单点定位GPS 5种不同测速设备，在小麦地、翻耕地、未耕地和水泥地等4种典型地表环境下进行农田作业机械测速性能试验。试验结果表明：在作业机械匀速行驶过程中，差分GPS（RTK-GPS和RTD-GPS）输出的速度值变异系数较大，单点定位 GPS、雷达与霍尔元件传感器输出的速度值相对稳定，与平均速度接近。而在作业机械加速和减速过程中，各种传感器测速误差均增大，其中单点定位GPS速度误差和测速延迟显著增大。田间试验和分析表明，低成本单点定位GPS和霍尔元件在正常旱田作业条件下，可以作为精准农业智能装备有效的测速手段。

Evaluation of ground speed measurements for agricultural machinery

Real-time ground speed measurement is an indispensable function of intelligent equipment for precision agriculture. The objective of this work was to evaluate the performance of different ground speed measurements under farm field conditions. Doppler radar, Hall Effect sensor, RTK-GPS, RTD-GPS and low-cost GPS were adopted for ground speed test on the surface conditions of vegetative cover with wheat, tilled soil, untilled soil and concrete floor. Results showed that speed deviations of RTD-GPS and RTK-GPS measurements were relatively high compared to other speed sensors, and ground speed measurements of low-cost GPS, radar and Hall Effect sensor were in close agreement with average speed under different conditions. While acceleration and deceleration speed test cases indicated that low-cost GPS has relatively higher error and obvious latency compared to other sensors. Based on the field experiments and result analysis, low-cost GPS and Hall Effect sensor can be used as effective method for precision agriculture intelligent equipment ground speed measurement under normal dry farmland.