| It can be seen that the precision strike weapons has been assumed as an important role inmodern warfare from the outbreak of a local war in recent years, while the key role is theimplement of the precision strike and the guidance technology． The high-precision, highreliability and strong autonomous navigation system are capable of providing high-precisionmotion parameter information for all kinds of moving bodies and the carrier, which is thebasis of the Tactical and strategic missiles for achieving the precision strike．In the field ofaerospace, separate means of navigation is difficult to achieve a long-range ballistic missilesin the requirements of high-precision navigation and precision-guided． To this end, thecombination of high-precision autonomous navigation system of ballistic missiles is thepresent and the future direction of development．Mature strapdown inertial navigation technology is used, in the context of thedevelopment of military weapons, as the main navigation system and the synthetic apertureradar image matching navigation system is used as aids to the navigation system． Theresearch of SINS/SAR integrated navigation filtering technique based on the platform of themissile-borne is an effective means to provide the high-precision motion parameters for theballistic missile．In this paper, the principles and the error analysis of the strapdown inertial navigationsystem and synthetic aperture radar image matching navigation system was studied． In thecontext of he ballistic missiles, the SINS error equation and the integrated system stateequation were built based in launch point inertial coordinate system according to the actualdemand, and the measurement equation was built based on the the SAR output of informationcharacteristics． Good filtering performance of UKF, nonlinear filtering method wasemployed in this case due to the nonlinear characteristic of the integrated navigation system,while the integrated navigation system employs the Perturbation state equation and themeasurement equation． And combining SAR measurements at irregular intervals andmeasurement hysteresis characteristics is to improve the existing UKF filtering algorithmfurther to meet the precision requirement of the integrated navigation system．Establish a mathematical model of the trajectory based on the ballistic characteristics ofthe ballistic missile under launch gravity coordinate system． The real-time position,velocity and attitude data were obtained by the trajectory equation under launch gravitycoordinate system, and then convert the data to the launch point inertial coordinate system asthe nominal trajectory data． Finally, the specific from inertial instrument and the angular rate information was extrapolated under the certain kinematic relations, which as the nominaloutputs of the accelerometers and gyroscopes．The pure inertial navigation system and the integrated system were simulatedlycombined with the trajectory data． It can be seen from the simulation results, the error ofthe missile’s attitude, velocity and location were largely using the inertial navigation systemalone, and it is difficult to meet the accuracy requirements． The SAR assisting navigationsystem was introduced at the end of the missile flight, which effectively estimates the errorand accurately correct it so as to achieving the desired positioning effect and providing theaccurate information support for precision-guided．In order to verifying the advantages of the improved UKF filtering algorithm, theconventional UKF filtering algorithm was introduced for comparison． The results show thatthe SINS/SAR integrated system can provide more accurate navigation parameters．Improved UKF filtering algorithm can more effectively and optimally estimate the navigationsystem parameter for the nonlinear and non-equally spaced hysteresis characteristics of theintegrated navigation system, So ie can improve the accuracy of the system．... |
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