Research On High-precision Ballistic Target Trajectory Space Reference System And Its Calibration Method

In the ballistic range tests,the error of spatial benchmark system and calibration method have great effect on the measurement accuracy of the projectile free flight parameters,this paper carried out the optimization design of the high precision ballistic range spatial benchmark system and the research on the calibration method of the shadowgraph station based on the spatial benchmark system.The working principle and calibration process of the ballistic range spatial benchmark system were analyzed.Through systematic analysis of the sources of errors and the magnitude of the measurement uncertainty introduced when calibrating the shadowgraph station with the spatial benchmark system and its transfer relationship,identified three critical control parameter of the spatial benchmark system the grid spacing?the distance from the center of the grid face and the distance between the stations in the X direction,and the improvement direction is proposed according to the problems existing in the existing spatial benchmark system.The shadowgraph station calibration method based on high precision spatial benchmark system and the performance verification method of the shadowgraph station were studied.A PSD positioning method based on single laser and the semi-transparent mirror has been raised,which used the laser beam parallel tube by the space benchmark optical axis,adjust the parallelism between benchmark carrier center axis and the muzzle line based on the degree of coincidence of the reflected spot and the incident spot on the optical target,adjust the coincidence between benchmark carrier center axis and the muzzle line according to the spot coordinates fed back by PSD.Adjusted the space position of the shadow camera on both sides of the target based on the spatial benchmark carrier in place to let the camera's optical axis coincide with the "cross grids type" grid center point of the relative grid surface of the benchmark carrier,and then three points reaching one line.Thus,the optical axes of the two side shadow cameras were orthogonal and perpendicular to each other to complete the calibration of the shadow camera.The laser interferometer was used to measure the standard angle of the simulated projectile's attitude change,and the angle between the standard angle and the shadowgraph method was compared,so as to verify the performance of the shadowgraph station.Design of the high precision ballistic range spatial benchmark system.The high precision ballistic range spatial benchmark system is composed of high accuracy double cross grids benchmark carrier,high-precision position adjustment mechanism and space reference axis alignment system.High precision double cross grids benchmark carrier adopted integrated design method,improved the precision of benchmark carrier.The analysis of the properties of different six dimensional adjusting mechanism were determined the choice of six DOF parallel robot as high precision position reference vector adjusting mechanism.After the reference light source analyzed,laser tube was selected as a parallel selection for the reference source and three tripod and cloud terrace were selected to achieve the benchmark source position adjustment.The design of optical window and installation and adjustment device has been done.The method of beam shaping,design of beam shaping device based on lens imaging,which effectively reduced the spot diameter,improved the beam quality and inhibited the PSD spot fluctuation and improved the measurement accuracy of PSD on spot position.A performance verification experimental device for the shadowgraph station is designed.The high precision reference material was used as the simulated projectile,and the combination of the swing platform and the rotary platform was used to realize the adjustment of the simulated projectile's pitching and yaw angle.The combined test and analysis of the system were done.The processing precision of double cross grids benchmark carrier has been verified by CMM.The laser interferometer has carried on the monitor to angle of Parallel Mechanism's movement with six degrees of freedom,whose accuracy of adjustment for position reached on 1'.The optical window and benchmark carrier's side parallelism was tested using table method,verifying the feasibility of optical window and the device for installation and adjustment.The test for beam shaping and position detection device verified the measurement precision of the module,which is less than 2um.Laser interferometer used to test the device for performance of shadowgraph station,verifying that the module can be adjusted in the range up to 10'.On this basis,the spatial benchmark has been set up to test,and the feasibility and reliability of the system have been verified.Analyzed the uncertainty influence factors for the gap of benchmark carrier's grids,the length between two relative meshes' center and distance between stations in the direction of the muzzle,got that the standard uncertainty for grids spacing is 0.0296mm,the standard uncertainty for the distance of relative meshes' center is 0.0675mm and the standard uncertainty for distance between stations in the direction of the muzzle is 0.47mm+lppm,which reached the requirements of design.