Design And Realization Of Radio Source Location System Based On Adaptive Hata Model

With the rapid development of mobile communications,radio communication systems have brought great convenience to people.Radio services have been integrated into all aspects of people's daily lives,providing various information services,and the demand for radio frequency ranges has increased.The degree of deterioration of the electromagnetic environment cannot be underestimated.Some unknown emission sources will also occupy frequency resources,so locating unknown emission sources is a major problem.Compared with the past methods,the radio source positioning system designed in this paper has two major advantages.The first is that it does not require the cost of a base station,and the second is that the positioning range is flexible and not restricted by geographical areas.The traditional method of radio emitter location is mainly divided into two steps.The first step is to obtain the parameters of unknown radio emitter,such as angle of arrival,time of arrival and so on.The second step is to use these known parameters and high-precision data to locate the unknown radio emitter.These methods must install expensive base stations and direction finding equipment in multiple locations,and require high precision for parameter values.This method uses field strength big data without the cost of building base station and direction finding equipment.The current radio propagation models are relatively fixed and require a large number of unknown emission source coefficients,such as the Longley-Rice model,Okumura-Egli model,etc.The obtained power value is fixed,and some unknown emission source coefficients cannot be obtained.The model cannot be used reasonably.In response to this problem,this paper proposes an adaptive Hata model that can solve this problem based on field strength data.The basic idea of this paper is to select some positions from the positioning range as the analog transmitter,and then according to the position and propagation model of each analog transmitter,the analog power value of the receiver can be obtained,and then the error value of the receiver can be obtained by making a difference with the real power value of the receiver,so that the overall error of each analog transmitter can be obtained by accumulating the errors of all the receivers From this range,the simulated emission source with the smallest overall error is the actual emission source to be solved.However,there are two problems in this basic idea.The first is that the calculation of propagation model requires unknown parameters of the emitter,which can not be obtained.The second problem is how to select the position of the simulated emitter,so that the error value of the emitter can be obtained is the smallest.For the first problem,if the traditional model is used,some parameters of the transmitter can not be determined,so this paper proposes an adaptive Hata model to solve the problem.The adaptive Hata model is based on the improvement of the traditional Hata model.The traditional Hata model needs many fixed coefficients,some of which are unknown parameters of the emitter.The adaptive Hata model can simplify the coefficients of the traditional Hata model.By using large data and particle swarm optimization algorithm,a new model can be obtained in each iteration The coefficients of the new model are adaptively changed according to the current iteration of particles and big data,so this paper is named adaptive Hata model.For the second problem,particle swarm optimization algorithm is used to optimize the positioning process in this paper,which can get the optimal solution faster without reducing the accuracy.Each iteration process of particle swarm optimization is a process of building an adaptive Hata model.For each particle,the error value of the particle can be calculated through the adaptive Hata model,which can be used for all particles The particle with the smallest error value is selected as the optimal particle,and then the other particles approach the optimal particle and iterate for several times.Finally,an optimal solution is obtained,which is the location of the unknown emission source.The experimental data in this paper are the field strength data obtained from a certain area in Changchun.Within the range of 8.83 km difference between East and West and 10.02 km difference between North and south,the positioning error values are within 0.4 km,and some can reach about 0.11 km.According to the experimental results,the proposed system can solve the problem of unknown radio source location.