Key Technology Research On Micro-satellite Low Observability

The key technologies on micro-satellite low observability are explored, to meet low observablemicro-satellite design needs. Compared to aerocraft low observable design, micro-satellite lowobservable design has some special characteristics:1) Detecting systems are distributed under themicro-satellite, and radar is the major threat.2) Most micro-satellites have limited orbitmaneuverability. It's hard for them to avoid threat by orbit transfer.3) The out space is clear, and thereis no object to shield the micro-satellite.4) Considering micro-satellite's limited energy, weight,cubage and strong space particle irradiation, RAM, FSS and active electronic countermeasure areunsuitable for micro-satellite.According to the characteristics above, micro-satellite low RCS shape design and low observableshape flight attitude planning are studied in this paper, and the following subjects are presented:1) Based on relative patents, similar technologies, threat development, also, considering lowobservable micro-satellite research and manufacture ability today, a research plan is proposed, whichis aimed to enhance the on-orbit micro-satellite's operational effectiveness and survivability by lowRCS shape design and low observable shape flight attitude planning. Plenty of existed similartechnologies and theories make the plan feasible and meaningful.2) An orbit-parameter-based threat evaluation model is proposed, to improve the precision andavoid the subjective analysis in existed models. According to micro-satellite orbit, RCS, LCS andthreat distribution, both threat existing probabilities and threat level in different directions could becalculated effectively in the model, which makes the evaluation result effective. Based on theorbit-parameter-based model, different micro-satellite orbits are calculated. According to the statisticalresults, a low observable micro-satellite orbit selection strategy is presented.3) A micro-satellite low RCS shape is proposed. The shape is separated from thermal andmechanics shape. Compared to the existed ones, the shape is simpler in structure and better inperformance. At the same time, a micro-satellite low observable shape optimization method isproposed. The optimization method includes three steps, which are key parameter selection, lowobservable performance evaluation and evaluation result fitting. Based on the optimization method,the low RCS shape optimization design is carried out quickly and efficiently.4) A static-environment shape attitude planning algorithm is proposed for micro-satellite earthstation, to find the global optimal flight attitude. A digital space model is established. Special planningspace compression methods are presented. Heuristic estimating function and refined OPEN/CLOSE tables are defined. Compared to the existed global optimal search algorithms, the static-environmentalgorithm has limited computational complexity, and is able to accomplish shape attitude planningunder different constrains stably and effectively.5) A dynamic-environment shape attitude planning algorithm based on particle swarm optimization(PSO) is proposed for micro-satellite application. The algorithm divides planning time into severalsections and processes the planning in each section separated. Taking advantage of the search strategy,the PSO-based dynamic-environment planning algorithm has very limited computational complexity,and the real-time performance is enhanced by thousands of times. In addition, the algorithm'scomputational complexity is independent of the planning space dimension and complexity, and thealgorithm is able to reduce the threat level of radar, laser detecting system and laser weapon at thesame time.6) Based on planning time dividing model, a dynamic-environment shape attitude planningalgorithm based on refined adaptive genetic algorithm (AGA) is proposed. A novel search strategy ispresented, special individual structure is defined, and refined crossover and mutation strategies aredesigned, to improve the algorithm's search ability and reduce the algorithm's computationalcomplexity. Compared to the classic AGA, within limited computational load, the algorithm has fasterconvergence speed, and meet the needs of micro-satellite with limited signal processing ability.7) Combined the static-environment planning algorithm's search ability and dynamic-environmentplanning algorithm's low computational complexity, a novel global planning algorithm is proposedfor shape attitude planning. A planning model based on threat evaluation function is established,extended link-list individual structure is defined, a simple fitness calculation method is introduced,and special individual production, reproduction, crossover and mutation strategies are presented, toenhance the global optimal flight atittude search ability and reduce the algorithm's computationalcomplexity. Accoding to the simulation results, within limited computational load, the algorithmworks better than existed static-environment planning algorithms and dynamic-environment planningalgorithms in low observable performance.