Study On The Flying Object's Pose And Position Measurement By Using The Optical-electronic Technology And Its Applications

Electro-optical measurement technology has the advantage of non-contact and highaccuracy,and it has an important application in the areas of the relative position andpose sensing for a flying object,such as the landing guidance system for a ship-bornehelicopter,and the optical guidance system in the spacecraft rendezvous and docking(RVD) process.These applications have high requirements for the measurementaccuracy and data update rate.Hence,researching on the fast and accurateelectro-optical measurement technology has important scientific significance andapplication value.An overview of the electro-optical measurement technology,the tendency and thefundamental theories are given,which is used in the helicopter's landing guidancesystem and the navigation system for the spacecraft RVD.An intensive study has beenmaken in theory and experiment on the pose estimation method,which is based on themonocular vision and the dual camera vision respectively,and on the laser range findertechnology,which is based on the phase shift measurement.The Orthogonal Iteration (OI) Algorithm is introduced,which has a fast convergentspeed,but the results have a large translation error in the close range,when using thethree-dimensional feature points.After the rotation matrix solution in the OI algorithmbeing refined,an efficient pose estimation algorithm is derived.Simulation results of theimproved algorithm show that the proper rotation matrix is always obtained,which inturn improves the accuracy of the translation vector.The comparison experiments showthat,when using the improved algorithm,the results of the relative distance and therotational angles are better than those using the OI algorithm.The improved algorithmhas a great theory and application value on the pose estimation system for atwo-dimensional object or a three-dimensional object.A relative position and pose determination algorithm is proposed based on the dualcamera vision,which can be used for the shipboard helicopter landing aid system.Twocameras are set on two sides of the object to acquire the characteristc points' image;the initial value of the pose of the object can be caluculated using the linear algorithm afterthe pointes coordinates extracted;then the nonlinear algorithm is used to obtain anoptimal solution.Based on the research of binocular vision measurement algorithm,thehelicopter landing aid demonstration system is setup.In this system,two high powersemiconductor laser illuminator devices and two precise CCD (Charge Coupled Device)cameras,a model plane and a high performance DSP signal process device are used.And the real-time image processing,object tracking,and pose estimation are realized.The outside experiments show that,the error of the relative object distance from thecamera is less than 5cm,and the rotational angle error is within±3°.The accuracy ofthe results is close to those of the ASIST (aircraft ship integrated secure and traverse)system.This demonstration system has not been reported in domestic.We use the Genetic Algorithm (GA) to solve the ill-conditioned equations,and awell-known camera calibration method based on the multi-plane is improved.Using themulti-plane calibration algorithm,both the characters of object space and image spaceare used,and accurate intrinsic parameters could be obtained,but the results may beunstable when the rotation angle of the pattern plane is small.Simulation shows thatmore stable and accurate results are obtained after it being improved.The distortioncoefficients under the backward projection model are computed,which can be appliedto a real-time measurement system.This calibration algorithm has important theory andapplication value.To determinate the flying object's position,we make some improvement on theconventional laser range finder based on the phase-shift measurement,and a fast andhigh accurate laser range finder method based on the phase-shift measurement isproposed.Instead of conventional mechanical switch and single receiving circuit,separate circuits and optical units were designed for the inside and outside beams,usingwhich the appended electornic phase shift is eliminated and the measurement speed isincreased.The Micro-Controller Unit (MCU) and Complex Programmable LogicDevice (CPLD) are used in the data processing and the logical control,which makes thecircuit design easier and improves the measurement stability.The experimental dataaccuracy is 81.181 mm (3σ),stability is 3.688mm (3ε) and data update rate is better than5Hz with the indoor measurements.This method provides an important reference for theengineering research.