精准对靶喷洒背景下作业小区地理坐标的计算方法

Research on the calculation method of the geographical coordinates of the operation area under the background of precise target spraying

【目的】确定作业小区的地理坐标是植保无人机实施精准对靶喷洒的关键问题之一。假如需要喷洒的作业小区数量众多或者需要喷洒的作业小区为水田等类型,可采用传统的人工在田间逐点测量的方法,则存在着工作量大、测量步骤繁琐、测量区域不易进入等缺点。因此,利用测量位于作业区域边界处或边界外有限数量位置点的地理坐标,然后按照一定算法计算出各作业小区的地理坐标就将克服前述的缺点,有着很大的实际应用价值,将极大提高精准对靶喷洒的效率和应用。【方法】根据实施精准对靶喷洒作业小区的地理坐标的求解需求,在测量学中找到一种地面点相对位置求取方法,同时将该方法引入并加以改进,分别提出了基于假定地球为正球体情况下的几何法和基于假定地球为椭球体情况下的投影法通过计算得到作业小区的地理坐标的2种算法,并且通过试验检验和比较2种算法的精度、求解速度、求解复杂度。【结果】通过试验可知,2种算法计算得到作业小区的地理坐标与实测值相比,误差在厘米级范围内,均符合实施精准对靶喷洒对精度的要求;在求解速度方面,几何法比投影法更加快速;在求解复杂度方面,几何法优于投影法。【结论】求解作业小区的地理坐标的2种算法-几何法和投影法在精度方面均可以满足实施精准对靶喷洒时对精度的需求。但是,在使用2种算法分别求解作业小区的地理坐标的过程中发现,在计算复杂度方面和计算速度方面,几何法相对于投影法更优、更简便、更适合实施精准对靶喷洒时对作业小区地理坐标的求解。

[Objective]Determining the geographic coordinates of the operation area is one of the key problems for the implementation of precision target spraying by UAV.If there are many operation areas to be sprayed or the operation areas to be sprayed are paddy fields,etc.,the traditional manual point-by-point measurement method in the field has the disadvantages of large workload,cumbersome measurement steps,and difficult access to the measurement area.Therefore,the geographic coordinates of a limited number of locations located at the boundary or outside the boundary of the operation area are measured,and then the geographic coordinates of each operation area are calculated according to a certain algorithm,which will overcome the above disadvantages and have great practical application value,and will greatly improve the efficiency and application of precision target spraying.[Method]According to the solving requirements of the geographic coordinates of the operation area for precision target spraying,a method for obtaining the relative position of ground points is found in surveying.At the same time,this method is introduced and improved.Two algorithms for calculating the geographic coordinates of the operation area are proposed,which are based on the geometry method assuming that the earth is a sphere and the projection method assuming that the earth is an ellipsoid.[Result]The experiments show that the errors of the two algorithms are in the range of centimeters compared with the measured value,which meets the requirements of precision spraying on the target.In terms of solving speed,the geometric method is faster than the projection method.In terms of solving complexity,the geometric method is better than the projection method.[Conclusion]The two algorithms proposed in this paper to solve the geographic coordinates of the operating cell-the geometric method and the projection method can meet the requirements of precision spraying on the target in terms of precision.However,in the process of solving the geographic coordinates of the operating cell using the two algorithms respectively,it is found that in terms of calculation complexity and calculation speed,the geometric method is better,simpler and more suitable for solving the geographic coordinates of the operating cell when implementing precision spraying on the target.