Research On Optimization Algorithm Of Equivalent Isotropic Radiated Power Estimation In Satellite Link Budget

An important task before building a new satellite communication ground station is to budget for the satellite link,so as to determine the equivalent isotropic radiation power of the ground transmitting station and ensure the reliability of satellite communication.The existing satellite link budget method based on the backward method has the advantage of maximizing the utilization of power compared with the traditional forward method,but the link parameters are set to fixed values in the budget process.The ambient temperature and humidity are constantly changing,and when the antenna aperture and position of the ground receiving station are different,the EIRP estimation of the ground transmitting station will be inaccurate.In order to improve the link budget accuracy,based on the GEO satellite communication scenario,this paper improves the link budget method based on the backward method,and proposes an optimization algorithm for the EIRP estimation of the ground transmitting station.The main research contents are as follows:Firstly,aiming at the link budget problem in clear weather,based on the analysis of the parameters related to link design and the basic principle of link budget,the relationship between the EIRP of the ground transmitting station and the uplink and downlink loss and the quality factor of the ground receiving station is deduced.The relationship between the above,the atmospheric absorption loss of the downlink and the variation range of the quality factor of the ground receiving station are established as constraints,and the optimization model of the ground transmitting station EIRP as the objective function is established.The gravitational search algorithm can efficiently solve the unimodal one-dimensional function and accurately solve the multimodal highdimensional function.The gravitational search algorithm is used to solve the global maximum of the objective function.Given the antenna gain of the ground transmitting station,the maximum value can be used as a reference for determining the minimum threshold of the transmitting power of the ground transmitting station.The simulation results show that the EIRP of the ground transmitting station calculated based on this method can adapt to the changes of the external environment and related parameters of the ground station,and meet the requirements of link margin.Secondly,the estimation algorithm of EIRP of ground transmitting station under rainy weather is further studied.Considering that the rainfall attenuation loss is strongly correlated with latitude changes,the map of China is first divided,and the rainfall attenuation loss at the same latitude in the same area is regarded as a fixed value,and the rainfall attenuation loss of the ground station at different latitudes is calculated separately.Then establish the above,downlink atmospheric absorption loss,ground receiving station quality factor,uplink and downlink rainfall attenuation loss variation range and satisfy the downlink carrier-to-noise ratio threshold as constraints,with ground transmitting station EIRP as the objective function optimization Model.The gravitational search algorithm is also used to estimate the global maximum of the EIRP of the ground transmitting station at different latitudes.In order to ensure the reliability of downlink communication,the calculation method of the antenna elevation range of the ground receiving station at different latitudes under the constraint of the downlink carrier-to-noise ratio is further given.The simulation estimates the minimum threshold of the EIRP of the ground transmitting station at different latitudes in the uplink and the range of the antenna elevation angle of the ground receiving station when the downlink carrier-to-noise ratio threshold is met.In summary,this paper introduces the optimization idea,transforms the estimation of the equivalent isotropic radiated power of the ground transmitting station into a constrained extremum problem,and uses the gravitational search algorithm to solve the optimization model,which is helpful for improving the link budget of GEO and other low orbit satellites.Accuracy is important.