Direction-finding Location Algorithm of Cloud Flashes
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摘要: 基于多站测向交叉算法,提出云闪侧向定位算法。根据各站仰角、方位角信息求解出各组闪电位置,由最大值和最小值约束条件剔除粗差较大的解后,引入加权运算得到较为准确的定位信息,再利用高斯牛顿迭代算法得到精准的云闪位置信息,从而实现云闪的三维定位。通过蒙特卡罗模拟方法,对算法进行评估,详细分析了站网多种因素对定位结果的影响。研究表明:该算法提高了定位精度,测向误差为1°时,4站站网误差低于500 m,站点越多定位精度越高,但综合考虑4站、5站站网为优,测向精度提高时,定位精度也随之提高;站网呈均匀布站方式优于T型等布站方式,均匀布站在实际中更具实用性。Abstract: Cloud lightning location is achieved by excluding solution with large gross errors to optimize initial solution, and joint constrained optimization of weighted integration and Gauss-Newton iterative algorithm based on the multi-station direction-finding cross-algorithm. The lighting position of each group is used as initial positioning solution, which is achieved according to elevation and information of azimuth. Initial solution is optimized through removing the solution with large gross errors by testing function of T-distribution, and then more accurate location information is obtained utilizing the weighted arithmetic. Cloud lightning location information is obtained accurately finally using Gauss-Newton iterative algorithm for constraint calculation. The algorithm is evaluated with the Monte Carlo simulation method, and then the influence of locating result is analyzed. Assuming the error of site layout is 10 m, the error of angle finding is 1°, the position precision is significantly improved using the algorithm of removing gross errors in four-station network simulation. The position precision of three-dimensiond angle of arrival loction (3D-AOA) is higher than integration solution under the same simulation conditions, which shows that the position precision is improved effectively by utilizing the weighted arithmetic and Gauss-Newton iterative algorithm. It shows that the accuracy of position is effectively improved and the deviation of four-station network is less than 500 m when the direction-finding error is 1°, and more stations lead to higher positional precision, but considering the balance of economic cost and precision, four-or five-station network is suggested. As the accuracy of direction-finding increases, the positional precision also increases. Analysis of different station network distributed shows that uniform distributed mode is better than others, the position precision of stations within a station network is clearly higher than stations out of the network. The error symmetry is convenient for analyzing data in practical application. Longer baseline leads to higher positioning accuracy of station network when the station number, station network structure and the direction-finding are fixed. Due to the sensitivity of finding system to the positioning distance, the error curve becomes less symmetrical when the baseline length reaches 100 km. The analysis on different baseline length of the station network positioning accuracy is only the theoretical result in the ideal case, a variety of factors such as instrument performance, detecting network, and hardware testing should be taken into comprehensive consideration in actual application.
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表 1 目标位置及不同定位算法处理的定位结果
Table 1 Target location and positioning results of different-algorithm processing
定位算法 P1 P2 估计值 距离差/km 估计值 距离差/km 站1、站2定位 (11.2841, 10.9815, 11.9707) 2.5487 (207.5448, 187.5402, 14.4163) 11.544 站1、站3定位 (489.967, -371.926, 54.201) 614.97 (121.5323, 163.0574, 6.8494) 80.337 站1、站4定位 (9.9387, 12.0577, 12.2632) 3.0594 (206.1214, 187.1350, 16.4622) 11.407 站2、站3定位 (9.6487, 9.3406, 11.1953) 1.4096 (194.5842, 176.9904, 11.1215) 6.2966 站2、站4定位 (-142.999, -143.828, 18.729) 217.14 (200.0445, 181.4351, 14.6315) 4.8489 站3、站4定位 (8.5626, 10.6550, 11.4343) 2.1337 (194.2440, 175.9943, 13.6423) 7.9021 加权融合 (25.9388, 7.3337, 14.3823) 16.744 (179.0228, 179.9303, 12.0337) 21.075 粗差加权融合 (9.9322, 10.7581, 11.7097) 1.8715 (196.9330, 176.7247, 12.0337) 4.9265 3D-AOA (9.9105, 10.0164, 11.7052) 3.7477×10-5 (198.0982, 180.9891, 12.6110) 3.3782 -
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