Study On The Acquisition Strategy Of Three-axis Photoelectric Tracking Equipment On Orbit

Monitoring on orbit is an important way to obtain the national space strategic information,and the passive monitoring and tracking system is an important part of the space target monitoring system in China.The ground passive monitoring and tracking system which has been operated mostly adopts the ground-based photoelectric tracking equipment,which can be divided into two-axis and three-axis photoelectric tracking equipment according to the structure classification.The three-axis photoelectric tracking equipment has the advantage of tracking the zenith target and is widely used.At present,the process of tracking space targets by photoelectric tracking equipment is guidance,detection,acquisition and tracking,among which acquisition is the key link to complete the task,and it is the important foundation and guarantee of high probability completion task.Most of the existing acquisition technologies aim at two-axis active equipment.However,the passive acquisition method based on the three-axis passive equipment has not been systematically studied.This paper is based on the analysis of the acquisition principle,based on the three-axis passive search and acquisition strategy for acquisition space target,and focuses on the short term and high probability "falling into" field of view of the target in the acquisition process.According to the analysis,there are mainly three steps to solve the problem of catching and falling into account,error source analysis,main error to the calculation of the field of uncertain,and design of search and acquisition method in the field of uncertain.In this paper,the above steps are discussed in detail,and a passive search method for the three-axis photoelectric tracking equipment is established,and the correctness of the model is illustrated by the simulation experiment.This paper first introduces the basic concepts and objects in orbit acquisition equipment with photoelectric tracking objects in orbit working process,combining the application of photoelectric tracking equipment to acquisition the objects in orbit three-axis analysis,there are many factors that influence the acquisition process pointing and target position deviation.Among them,the main error is the key to determine the scope of the search,and the secondary error can be ignored.Therefore,the error transfer method can be used to calculate the proportion of each error in the total error,and the main error and secondary error can be obtained.The main calculation errors include orbit prediction error and three-axis photoelectric tracking equipment pointing error.Then,the transfer model of the main error to the field of uncertain is established.The orbit prediction error to determine the transfer does not need to go through the process of regional space coordinate transformation,and so on several space coordinate systems are introduced,including the geocentric inertial coordinate system,earth fixed coordinate system,station coordinate system and coordinates system.When the orbit prediction error from earth fixed coordinate system through fixed azimuth guidance mode is transferred to the measurement of three-axis photoelectric tracking equipment value,the need to introduce three-axis photoelectric tracking equipment pointing error transfer.Through the introduction of the above two stages of error and spatial correspondence,we can finally calculate the range of the field of uncertain and the distribution type of the target location in the field of uncertain.In this paper,some typical space targets are enumerated.The transmission results from the main error to the field of uncertain are calculated,and the data distribution type of the target location distribution is tested.It is calculated that the distribution types of target locations in different regions with different orbit heights obey the two-dimensional normal distribution,and mainly focus on the X direction of the field of uncertain,that is,the direction of the space target along the velocity direction.The range of the field of uncertain determines the maximum scope of the field of view.However,in the field of uncertain,the way to search and acquisition,where to start the search and the average time to acquisition is still unknown.For this reason,several commonly used search and acquisition methods are discussed.Through comparative analysis,it is found that the location of the target is concentrated in the field of uncertain along the speed direction,and the spiral search is suitable.At the end of this paper,the Monte Carlo method is suitable for the simulation of the search acquisition experiment.The calculation results of the field of uncertainty of some typical space targets are selected.By searching the modules of the acquisition system,we calculate the relationship between the acquisition scope and the average acquisition time of the spiral search and acquisition method and the acquisition probability of multi-field search and acquisition.By the analysis of experimental results shows that the spiral search and acquisition method of overlapping rate is high and low search efficiency,so the design of the spiral branch of non-equidistant search,verified in the same acquisition probability under the condition of non-equidistant spiral branch search of the mean acquisition time is better than the traditional spiral search.To sum up,according to the actual demand of the three-axis photoelectric tracking equipment in the passive way to search the space target,this paper systematically analyzes several steps in the acquisition method,and finally establishes a complete set of three-axis photoelectric tracking equipment to search the space target for the capture of the space target.This method is on the three-axis photoelectric heel equipment.It has certain reference value to search and acquisition space targets.