本文针对太阳影子定位问题，通过对影响物体影长的各个参数进行分析计算，以反演杆长最优为目标建立基于多参数分层搜索的杆长优化模型，利用MATLAB仿真从而实现太阳影子定位技术。首先建立基于太阳高度角变化的直杆影长变化模型，得到直杆影长与赤纬角、时角等变量的函数关系式；其次，运用控制变量的方法分析影长关于直杆长度、所处经度、纬度、测量日期以及测量时间的变化规律并作出2018年9时至15时(北京时间)的直杆影长变化曲线，发现影长随时间的推移先减小后增大，在11时45分取得最小值约为2.1 m；最后，本文通过实际测量的方法对模型进行检验，得到模型结果相对实际测量值的误差约为1.732%，模型有较高的精度。对于影子定位问题，通过几何关系得出直杆影长与影子顶点坐标数值的关系；针对直杆所在地点未知的情况，本文应用同一地点不同时刻的影长和太阳高度角反演得到的杆长相等的原理建立起基于参数分层搜索的杆长优化模型，以同一地点多组杆长值中极差近似为零为目标；利用MATLAB对经度和纬度先后进行粗搜索和精搜索，得到两组可行经纬值分别为：(108.4566？E, 19.2771？N)及(103.1670？E, 3.2552？S)；第一组经纬度对应位置为近海南省的海上，其经度与海南省经度误差为1.256%，所以本文在误差允许范围内将第一个地点定为海南省，第二组经纬度对应位置为印度尼西亚。
In this paper, aiming at the problem of sun shadow localization, by analyzing and calculating the parameters affecting the shadow length of the object, the rod length optimization model based on multi-parameter hierarchical search is established with the aim of inversion of the rod length, and the MATLAB simulation is used to realize the sun shadow positioning technology. Firstly, a straight-line shadow length variation model based on the change of solar height angle is established, and the relationship between the straight shadow length and the declination angle and the time angle is obtained. Secondly, the control variable is used to analyze the length of the straight rod. Using the method of control variable to analyze the variation rule of longitude, latitude, measurement date and measurement time and the curve of the straight shadow length from 9:00 to 15:00 (Beijing time), it is found that the shadow length decreases first and then increases at 11:45. The minimum value obtained is about 2.1. Finally, the model is tested by the actual measurement method, the error of the model result relative to the actual measured value is about 1.732%, and the model has higher precision. For the shadow localization problem, the relationship between the straight shadow length and the shadow vertex coordinate value is obtained through the geometric relationship. For the case where the straight rod location is unknown, this paper applies the long length of the shadow length and the solar elevation angle inversion at the same place. Based on the principle of the parameter, the pole length optimization model based on parameter hierarchical search is established, and the range of the poles in the same group is approximated to zero. The MATLAB is used to perform rough search and fine search on the longitude and latitude. The feasible longitude and latitude values are (108.4566？E, 19.2771？N) and (103.1670？E, 3.2552？S).
