A Study Of Geolocation Method Of Short-Wave Signal Emitting Sources

Short-wave communication is the main way to achieve long-distance communication,in many applications of shortwave communication such as maritime search and rescue,forest fire prevention and other scenarios,shortwave signal transmission source location information has a very important value.In order to achieve high-precision geolocation,we need to establish a short-wave propagation path model,and according to the path model,the geolocation problem of the short-wave signal emitting source can be described as a certain type of optimization problem to be solved.In this paper,we studied the establishment of an equivalent path model under the QP ionospheric model and the solution method of geolocation optimization of short-wave signal emitting sources.The main work and contributions of the thesis include:(1)The establishment of an equivalent path model of propagation path under QP ionospheric model is studied.In the scenario where multiple receiving stations jointly geolocate the short-wave signal emitting source,an equivalent path model is established based on the short-wave propagation path model under the QP model:under the circular array antenna structure,the group path,phase path,equivalent path and the difference between the equivalent path and the phase path from the short-wave signal emitting source to the array elements of a receiving station are a sine function after translation,amplitude transformation and phase shift,and the phase shift parameters of these paths and path differences are equal.(2)The geolocation optimization problem of short-wave signal transmission source is solved and the optimal performance boundary is derived.Based on the functional model of path difference,the geolocation optimization problem of the short-wave signal emitting source is established,and the optimization solution algorithm is designed based on the augmented Lagrange multiplier method,the quasi-Newton method and the Armijo line search criterion to solve the problem,the simulation results show that the optimal solution under the diameter of each array is very close to the emission source when there is no measured noise in the phase path.Secondly,the optimal performance boundary CRB of the short-wave signal emitting sources’geographical location estimation is derived,and the Monte Carlo experiment is performed when there is measurement noise in the phase path,and the results show that the RMSE of the CRB and Monte Carlo test results decreases with the increase of the diameter of the array,decreases with the increase of the number of stations,and is related to the geographical distribution of the receiving station,the geolocation accuracy can effectively improve when using multiple snapshots.In addition,the Monte Carlo test results failed to reach its optimal performance boundary CRB,which is due to the fact that the optimal solution solved using the quasi-Newton method at certain initial and noise points is a local optimal solution rather than a global solution.