In view of the negative effects of resonant cavity deformation due to complex environments on performance of laser gyroscope, the slight deformations of mirror in three directions, which are 0.342 5″, 0.349 4″ and 0.215 0″, was simulated by ANSYS when the resonant cavity was under the function of standard random vibration spectrum(gRMS=6.6 g). Employing the theory of matrix optics, the deformation of the diaphragm was obtained quantitatively. Then, the deformation law of optical resonant cavity affected by radius of curvature, cavity length and incident angle was analyzed in an optical quadrangular cavity. Finally, the deformation law of optical path was derived when the spherical mirror and spherical mirror changed simultaneously or the spherical mirror and plane mirror changed simultaneously. Only considering the vibration resistance, the deformation of quadrangular cavity generated by the external environment is slighter with the smaller radius of curvature and the shorter cavity length when the radius of curvature ranges from 0 to 8 m and cavity length ranges from 0 to 1 m. Furthermore, the deformation law of two mirrors can be equivalent to that of a single mirror according to certain rules. The research can provide a reference for the design of optical resonant cavity of laser gyroscope.

Aiming at the inaccurate parallel-alignment of two display screens in three-dimensional (3D) measuring system of specular surfaces, this paper proposes a method for generating deformed fringes by software to be equivalent to the exact parallel-alignment of two display screens. The machine vision technology was employed to calibrate external parameters of the two displays, based on which the deformed fringes equivalent to parallel-alignment two display screens were produced by software programming. A camera captured the parallel-alignment fringe pattern through the beam splitter in the camera coordinate system. The difference of the corresponding phase was calculated with the deformed fringe patterns on the two display screens. The proposed method was quantitatively evaluated by the errors of root-mean-square. Experimental results show that the proposed method can reduce the errors of root-mean-square to 24.21% in horizontal direction and 8.15% in vertical direction of the original ones respectively, thus improving the accuracy of 3D measurement system.

Magnetic beads are widely used in biological experiments, such as immunoassay and cell separation. The detection of magnetic concentration is profound to the evaluation of experimental results. Therefore a magnetic beads concentration measuring system with dual optical path based on laser transmission method was presented. The concentration of magnetic beads was determined by measuring the ratio of the intensity of incident laser to the intensity of the transmitted laser. A series of magnetic bead suspensions with various concentrations were tested. For each concentration, the measurement was performed for many times and a total of 8,000 sets of data were collected. By fitting the measured data, the relational function between beads concentration and output data can be obtained. The relation between the concentration of magnetic beads and output data was well fitted exponentially. The fitting residual sum of squares is 0.000 088 89 and the determination coefficient is 0.997 1, which illustrate good fitting ability of the model. The experimental results show that the relative measurement error is less than 2.5% and the output data fluctuates within 2.5%, which indicate that the beads concentration measurement system based on laser transmission has high measurement accuracy and good repeatability.

In order to ensure full waveband range of echelle spectrometers, a set of calibration devices was designed. The principle, range and resolution of the calibration were discussed and studied. First, tolerance analysis of optical elements in the echelle spectrometer was performed, and the principle and process of auto spectrum calibration were introduced. Taking the focusing mirror as the adjusting object, the requirement of adjusting resolution was given according to the usage of the CCD image. Furthermore, a set of calibration device was designed, and the calibration resolution of the devices was calculated and experimentally verified. The results show that the azimuth calibration resolution is up to 0.006 25°, the resolution of the pitching direction is up to 0.006 25° and the resolution of the front and rear direction is up to 0.005 mm. The calibration devices can adjust the 10 pixels band offset to the normal reception range of the CCD, thus ensuring the full spectral band range of the spectrometer.

In order to improve the reliability and real-time performance of polarized skylight navigation, a independent position method based on multi-polarized lights was proposed and a navigation prototype was constructed. The prototype included five polarized light sensors, which were arranged in multi-direction array for the detection of polarization information in multiple directions of the sky. With the polarization information optimized and converged, the sun spatial position information was calculated more reliably and accurately. Finally, the position information of the prototype was determined according to the sun spatial position information, the time and the geomagnetic field information, thus realizing real-time position. The PC program of the prototype completed by LabVIEW can collect and process the date from the sensors in real time, meanwhile calculate and display the longitude and latitude of the location of the prototype synchronously, with a data update rate up to 10 Hz. The test results show that position accuracies are ±0.4° and ±1.2° in longitude and latitude respectively, which indicate that the navigation prototype is feasible and stable and can be applied to real navigations.

In order to characterize the photon luminescence properties of up-conversion nanoparticles(UCNPs), a system to measure fluorescence life time of single nanoparticle was established based on a custom-built two-photon microscope scanned with a pair of galvo-mirrors. First, a sample of mono-disperse UCNPs was imaged by the two-photon microscope. Then, the exact location of each nanoparticle was precisely determined through the single molecule fluorescence localization algorithm. The laser was focused on the nanoparticles one by one with a laser pulse with 500 μs duration exerted on the nanoparticle. A photomultiplier was employed to measure the time-lapse fluorescence intensity which varied with time. Finally, the fluorescence decay curve was fitted to calculate the life time of single nanoparticle. The experiment results show that the fluorescence curves of single nanoparticle fit with single exponential decay, and the fluorescence life time is 195.3 μs. For contrast, the life time of the bulk sample is 358.9 μs. This indicates a dramatic effect of particle aggregation on the photon luminescence properties of UCNPs.

Aiming at the problems of polarizing effect in short wave infrared and measurement deviation in the polarization spectral measurement system built in lab, a system calibration model was established and a method to measure the correction coefficients of the model was proposed, thus the polarizing effect was calibrated precisely. Firstly, the main problem of the regular time-divided polarization spectral measurement system was described and the origin of the polarizing effect was analyzed. An ASD spectrometer which had a serious polarizing effect functioned as an analyzer according to the polarization transmission theory. Thereby a system calibration model was established and verified by comparing with the ideal model widely used. Then, a high precision fitting method of the correction coefficients was proposed for improving the measurement accuracy based on the analytical method. Experimental results indicate that the calibration precision is higher than 0.5%, which can fully satisfy the requirements of target polarization information processing in laboratory. This method has a great significance for the development and calibration of polarization spectra measurement system.

To explore the relationship between the local oscillator power and the coherent detection sensitivity in free-space coherent optical communications, the mathematical model about the influence of the local oscillator power on the sensitivity of coherent detection was established, and the effect of local oscillator power on the sensitivity of coherent detection under different parameters was simulated. The coherent detection sensitivity testing system was set up by using the high-speed and large-area space-coupling balanced detector produced from Wuhan University, then the effect of the local oscillator power on the detection sensitivity was verified experimentally. The experimental results show that the detection sensitivity is always affected by the intensity noise of the local oscillator due to the dismatch of the two photodiodes in the coherent detection system; thus there exist an optimal local oscillator power which can realize the maximum value of coherent detection sensitivity with certain environment parameters of the detector. When the bit error rate is 10-12 and the communication rate is 5 Gbps, the maximum value of the coherent detection sensitivity in the test is -40.16 dBm and the corresponding optical power is 9 dBm. The proposed model has an guiding significance for the improvement of detection sensitivity of coherent detection systems.

In order to enhance the available probably ratio and to improve the temperature level and difference in a specific geostationary earth orbit (GEO) laser communication system, the structure of baffle was optimized. The baffle was uniformly installed grids on internal surface on the basis of GEO orbit external thermal flux characteristics, without the decrease of laser communication signal property. Firstly, the impact of grid and baffle inner wall on the solar view factor of the primary mirror was discussed in terms of energy shield ratio standard less than 5%. Then, the thermal simulation of temperature level and difference on the primary and secondary mirrors were performed by IDEAS, in which the influence of number and layout of grids on temperature indexes was analyzed. Finally, the laser communication available probably ratio with the optimized baffle was calculated. The results show that deploying 4 equally distributed grids along both parallel and vertical directions to the equator in the baffle, the available communication probably ratio is raised from 81.51% to 91.21% in comparison with the one of traditional cylindrical hollow baffle.

To study the influence of tangential flow on laser damage of slow small targets, a research on the effect of tangential airflow on laser ablation in the process of laser irradiation on a typical low slow small target material of nylon 66 was achieved experimentally and in simulation. The physical model of laser ablation on nylon 66 was established. Based on the model, the temperature field distribution and ablation morphology of nylon materials for 4 s and 1.5 s laser irradiation with and without tangential airflow recorded by a thermal infrared imager were analyzed. The experimental results show that the effect of tangential airflow on the process of laser ablation of nylon 66 is divided into two main stages: in the irradiation early stage, the tangential airflow slows down the thermal increase of nylon 66 materials under laser irradiation, thus restraining the laser ablation of nylon material; However, with the rise of temperature, the increase of the thermal decomposition products leads to laser shielding effect enhancement, thus the tangential flow reduces the attenuation of thermal decomposition products on the surface of target materials to laser and can provide more oxygen for ablation of nylon material. Finally, the process of laser ablation on nylon was simulated by ANSYS. The simulation results are in good agreement with the experimental results, which verifies the reliability of the theory.

In order to simulate the annual solar irradiation of a satellite in orbit, thus verifying and optimizing the ability of entire satellite to stray light suppression, the paper analyzes on-orbit imaging condition of optical payload and designs a scanning xenon lamp solar simulator, which has a ten dimensional scanning system including 7-dimension scanning mirror and 2-dimension folding mirror and 1-dimension sample. The controlling formula of all the mechanisms in terms of attitude and location are deduced. Then the simulation of irradiation in space environment is completed. The results show that the solar simulator scans an area of 1 700 mm×2 700 mm with the azimuth angle from -90 ° to + 90 ° and the pitch angle from -29 ° to 42.5 °. Their angular accuracies are up to 0.2 ° and 0.1 ° separately, and the position accuracy is better than 10 mm. Thus the scanning solar simulator can be applied to the accurate simulation of year-round solar irradiation condition for some satellite in orbit.

The correct prediction of subsurface damage (SSD) depth in lapping is an important basis for setting processing parameters. According to the lapping features of fixed abrasive, two typical optical hard-brittle materials (MgAl spinel and quartz glass) were selected to establish their respective two-dimensional discrete element models by using the discrete element method (DEM) and to analyze the impact on SSD (crack) depth of optical hard-brittle materials by above processing parameters. After that, an angle polishing method was used to measure the SSD depth of lapped MgAl spinel and quartz glass and to have it verified by experiment. The results show that when applying fixed abrasive for lapping, the abrasive particle size will have a significant impact on the SSDs of optical hard-brittle materials, which means under same lapping processing, the greater the abrasive particle size is, the deeper of SSD and the denser the micro cracks will be. The comparison between experimental results and DEM simulation results indicates that DEM is able to make quick and effective prediction on SSD depth of optical hard-brittle materials and to provide reference and guidance for subsequent lapping and polishing processing.

In order to achieve high-accuracy trajectory tracking at feed end of Five-hundred meter Aperture Spherical radio Telescope (FAST) support system and to prevent the force over-limit of supporting cables, the pose distribution algorithms of target end by the star-frame of feed support system and A-B rotator were studied in the article. Firstly, according to the mechanism characteristic of the feed support system, combining the time-varying barycenter and the back illuminating strategy applied in feed cabin, a mechanical model of cable-driven parallel system which considers the time-varying barycenter of feed cabin and provided with back illuminating strategy was established. Secondly, in order to solve the motion coupling between the A-B rotator and the star-frame, two pose distribution algorithms of the feed support system were designed: the pose distribution algorithm which gives priority on ensuring the balanced cable force of six-cable and the pose distribution algorithm which gives priority on ensuring the positioning accuracy of the feed receiver. Finally the performance of above two algorithms on positioning accuracy of the feed receiver and the distribution of cable force were analyzed. And the results show that the former algorithm is able to balance the cable force on six-cable, however the error due to introduction of maximum 1.2° of the feed receiver has been beyond the scope of the specified accuracy of the project. The second algorithm makes cable force on six-cable fluctuate significantly, but the force was not over the limit or under virtual pull, which means such algorithm meets engineering requirements because it can ensure the pose of the feed receiver.

Subject to space development requirements such as lightweight, miniaturization and simplication, the carbon fibre reinforced plastic (CFRP) lenticular tape spring (LTS) was practically designed through theoretical analysis, and its buckling characteristics was studied by combining finite element analysis and experiments. The bending moment computing formula for CFRP LTS under different anisotropic materials was deduced according to bending theory of thin shells, and the sensitive parameters that affect LTS's buckling characteristics were analyzed. Secondly, subject to engineering needs, a practical design on single CFRP LTS was performed and the finite element model was established to obtain the bending moment-rotation angle curves. Finally, the real object of CFRP LTS was fabricated and an experiment was conducted to study its buckling process. The results show that the critical bending moment of such CFRP LTS is 1 237.6Nmm and the maximum error is 8.7%, which is much corresponding to theoretical analysis and the results of finite element simulation, such results verifies the accuracy and compliance of the theoretical analysis and finite element simulation, provides theoretical foundations and technical supports for subsequent design and application of CFRP LTS.

In order to design a large deformation of flexure hinge with high precision and simple structure and to promote the motion precision of parallel platform and the life of elements, a Y-type flexure hinge was proposed in the article. Firstly, made analysis and study of the rotation center, installation method and stroke requirements of flexure hinge by application of ANSYS and ADAMS. Secondly, processed the flexure hinge by using CNC machine. Thirdly, measured the axis drift of flexure hinge by using the 3D optical coordinate measuring instrument OPTOTRAK. Finally, conducted the circle trajectory experiments of parallel platform with kinematic pairs, leaf spring flexible hinge and Y type flexible hinge. The results show that the maximum rotation error of Y type flexure hinge is 0.596 2 mm and the maximum error of circle trajectory on the parallel platform provided with Y type flexible hinge decreased by 42.7% as compared with on the parallel platform provided with kinematic pairs, which means Y type flexure hinge can substitute the kinematic pairs in the parallel platform and able to promote the motion precision of the parallel platform.

Dynamic atomic force microscope (AFM) is able to measure the surface topography of objects by detecting the changes of resonance state of the cantilever. Through the detection on three factors of such resonance state, amplitude, phase and frequency, dynamic AFM could be divided into three kinds of working modes, which are amplitude feedback mode, phase feedback mode and frequency feedback mode, and such feedback modes have different scanning characteristics. Based on the higher-order resonance characteristics of the silicon cantilever, dymamic AFM is able to scan objects when the cantilever is working under the high-order resonance. By combining above working modes, a multi-mode dynamic AFM was developed, which could scan and measure the objects under the above three feedback modes and different order of resonance state. The results of scanning tests under different feedback modes and different order of resonance state by application such system show that the system has sub nanometer resolution in each working mode, in which the system can achieve the optimal sensitivity and resolution under phase feedback mode and when the cantilever runs under the second order resonance, which is 17.5V/μm and 0.29nm respectively. Uuder such optimal sensitivity and resolution, the three dimensional scanning test of grating is conducted to obtain its 3D topography image.

The vibration disturbance generated by Control Moment Gyro (CMG) has adverse effects on precision and stability of the attitude control system in spacecraft and there is still lack of effective methods to conduct mathematic modeling and analysis on it. Due that there is large structure difference between high-speed rotors and low-speed components of CMG, and it is hard to make mathematic modeling with unified methods, a system modeling method combined analytical modeling with test identification was established in the article to study the disturbance transmission mode of CMG, and an experiments was conducted to verify it. The results show that the disturbance transmission model proposed is correct and able to verify the conclusion that “unbalance vibration of high speed rotor is the main disturbance resource in CMG”.

To discuss the impact of bearing parameters, including the restrictor size, air film thickness and air supply pressure, on mechanical performance of the orifice restricted aerostatic bearing. Firstly, taking the orifice restricted hydrostatic thrust bearing with cylindrical chamber for an example, carried out a numerical simulation and analyzed in the bearing clearance flow field, in which the orifice size, air chamber size, air supply pressure and air film thickness were taken as the design variables, established an orthogonal array by utilizing the basic principle of orthogonal experimental design, and then took samples through numerical calculation of the bearing clearance flow field to obtain load carrying capacity and stiffness of the bearing; secondly, built an analysis mathematical model for load capacity and stiffness, in which the functions of each parameter and the impact of flow field structure on the mechanical performance were taken into consideration, within the range of design variables based on the radial basis functions model, and the obtained model was proved with sufficient precision through fitting verification; finally, analyzed the impact of orifice size and air chamber size on load capacity and stiffness of the bearing, which provided a reference for engineering design.

In consideration of the disadvantages such as boundary distortion and poor adaptability in the method for microstructure surface error separation, the bidimensional empirical mode decomposition (BEMD) with adaptive time-frequency resolution capacity was put forward and applied to three-dimensional engineering surface error separation; at the same time, Riesz transform was utilized to construct monogenic signal, calculated overall frequency characteristics of the signal and improved the termination criterion for bidimensional empirical mode decomposition, thus keeping it in strict accordance with the error specified in ISO4287 for each frequency band of the 3D surface with cutoff wavelength and long separation. The simulation results show that compared with Gaussian filter in ISO and commonly-used wavelet filter, this new method can achieve a far better separation effect than traditional methods in error separation for 3D engineering rough surface, and the 3D evaluation parameter errors corresponding to the error in each frequency band are all lower than 5%. Finally, an instance analysis was conducted in the optical filming elements, and the results show that the method can well separate the spatial information of each surface error, and the reference surface for parameter evaluation is free from problems such boundary distortion compared with traditional methods. Hence, the application of the method in actual engineering surface error evaluation is of great feasibility.

To better evaluate and distribute the middle frequency errors of large telescope, structure function was put forward for such purposes in this paper. Firstly, we carried out a derivation in basic property of the structure function and compared it with traditional root mean square (RMS), which indicates its capability of representing different-scale errors; secondly, conducted an analysis on the statistical property difference of system wavefront under different evaluation scales, which indicates that system error distribution can better follow the normalized distribution under small scale and tend to deviate from the normalized distribution with the scale increase (e.g.: a scale greater than 100 mm); then a method for middle frequency error distribution of large telescope that can simultaneously cover multiple error sources was put forward based on basic property of the structure function; established a conversion relation between the structure function and normalized point source sensitivity (PSSn) put forward by TMT team, and then completed the cross validation among the error distribution indexes and transfer of techniques; finally, carried out an error distribution in primary mirror system of a large telescope based on the method put forward in this paper, which indicates that structure function of the system can meet the requirements under the condition where large-scale RMS is 25nm, roughness is 1nm, middle frequency scale is 250 mm and atmospheric coherent length is 0.4 m (testing environment), and that PSSn=0.9996 obtained from the structure function is greater than PSSn=0.999 5 directly obtained from mirror data can also meet the corresponding requirement.

Purpose: to improve the fuel economy of vehicles with MB-CVT, a control algorithm based on sliding mode extremum seeking (SMES) theory and an integrated control method based on combination of SMES control and traditional clamping force control were put forward. Method: designed the integrated control system based on a combination of SMES control and traditional hydraulic control, and established a mathematical model with nonlinearity and discreteness; analyzed the special curvilinear relationship between the efficiency of continuously variable transmission (CVT) and slip ratio of metal band (MB); tested the clamping force ratio coefficient of drive/driven wheel, and achieved the design for speed ratio tracking controller and changed ratio flow; completed the SMES controller design based on principle of the SMES algorithm, and carried out whole vehicle testing in the running drum tester with environment chamber. Conclusion: the test results show that fuel consumption for vehicle with MB-CVT which adopts the integrated control is 7.18L/100km, 5.64% lower than fuel consumption of traditional control system, and inverse indicator for pressure safety index of both the drive wheel and driven wheel is lower than 1, which meets the reliability, stability and optimal performance for improvement of whole-vehicle fuel economy.

Purpose: to achieve on-orbit servicing or off-orbit removal of non-cooperative targets in space, such as inactive satellites, space debris, especially slowly rotating targets, accurate measurement of relative attitude between the tracking aircraft and target aircraft is necessary. Method: firstly, used inverse depth parameterization to represent the coordinate value, angular altitude, azimuth angle and depth information of the camera, which could effectively complete the monocular vision attitude estimation under small parallax error; secondly, established a motion model and measurement model of the camera relative to the non-cooperative target; finally, achieved the relative motion attitude estimation between the camera and target based on single candidate RANSAC and EKF. Results: for three-axes stable targets, the attitude measurement accuracy during the approaching process is approximately 0.5°; for slowly rotating targets (constant velocity), the relative angle error is about 3.5%, with an average angular velocity error of approximately 0.1°/s. All these parameters can meet the requirements for relative attitude measurements of engineering spatial non-cooperative targets.

Considering that some triangular mesh models are inconvenient for storage, analysis and display due to enormous data volume, a simplification algorithm for triangular collapsed mesh combining with mesh refinement was put forward. In this method,the modified coordinates for three vertexes of the triangle to be collapsed were determined by using the 3 surface subdivision method, and the position of the folding point was preliminarily determined in accordance with the modified coordinates; then the Laplacian coordinate of the folding point and normal information of the original triangle were introduced to update the folding point position; finally, the collapse cost was caculated based on volume error of the area after triangle collapse and flatness of the collapsed triangle, thus enabled the mesh to preferentially carry out collapse simplification from relatively flat area with few feature points. Experimental test and data analysis were established in multiple models, and result indicates that the method can effectively simplify the mesh data. Compared with three simplification methods of different types, the method can achieve the highest simplification efficiency, and can, at the same time, effectively maintain geometric characteristics of the mesh model and control quality of the simplified triangle.

For small-scale image locating in a large image, an accurate locating method combining deep convolution network with SURF registering was introduced. The large-scale image was divided into several small reference images, and the feature of such reference image set was extracted to form a feature library by combining the deep convolution network and Similar Local Sensitive Hashing (SLSH); on the basis of the feature library, a two-stage method that carrying out accurate SURF registering after retrieval of multiple similar reference images was put forward to achieve the locating of small target in a large image. Experiment was established on high density FPC and location data of accurate final guidance image,and the results indicate that the method avoids approximately 90% in the amount of feature extraction by comparing with traditional SURF locating methods, in which registering is directly carried out in accordance with image features.So the method can ensure the locating precision, meantime can lower the time consumption by more than one order of magnitudes.

Considering the low precision of low-resolution image used for the registration process, a sub-pixel image registration method based on super resolution reconstruction was put forward. Firstly,10 times down-sampling was carried out in the image sequence with 1~9 pixel displacement to obtain an image sequence with 0.1~0.9 sub-pixel displacement; then, a mathematical model was built in accordance with the image acquisition process, and Maximum A-Posteriori (MAP) method was used to carry out super resolution reconstruction in low-resolution image of the sub-pixel displacement to obtain high-resolution image based on the Bayes Theory; finally, the extended phase correlation method with sub-pixel registration accuracy was applied to conduct image registration. The registration and noise experiments inclicate that the maximum registration error is 0.03 pixel. The proposed method has high registration accuracy and strong anti-noise ability. It can realize the sub-pixel registration for low-resolution image, at the same time, it can meet the requirements for high-accuracy registration of visible image and infrared image.

To alleviate the dependence of binocular camera on high-accuracy target during calibration, achieve precise calibration of camera parameters and implement high-accuracy reconstruction of space coordinates, a GPS-based method for binocular camera calibration and space coordinate reconstruction is introduced, in which GPS instead of 2D or 3D targets is used to carry out the camera calibration.Through arbitrarily moving the GPS at the shooting site, multiple images with GPS are shot by calibrated camera; based on the mapping relation between spatial 3D coordinates and 2D image coordinates, the binocular camera parameters are calibrated and precise reconstruction of space coordinates is carried out by combining camera imaging model with calibration theory of binocular camera; finally, the reconstruction accuracy is tested in accordance with relative distance error between the space reconstruction coordinates and actual measurement values. The reconstruction results of proposed method are compared with the true data obtained by the GPS,and the results indicate that the method can help binocular camera to overcome the dependence on high-accuracy targets and equip the space reconstruction coordinates with relatively high accuracy, with a relative distance error decreased from 1.56% to 0.52%.

To solve the problem of initial attitude estimation for inflight loitering munition in the absence of reference attitude, a fast initial attitude estimation algorithm for adaptive reference vector weight (AFCF) was put forward based on the Attitude and Heading Reference System (AHRS) designed by adopting low-cost magnetic,angular rate and gravity MARG sensor. First of all, a fast error calibration method for three-axes sensor was put forward; Then,the attitude estimation was carried out by adopting the fast complementary filtering algorithm, and the impact of weighting function on initial attitude estimation and convergence was analyzed; subsequently the method for adaptive reference vector weight and adaptive attitude estimation was proposed; finally, high-precision MTI sensor data was used to verify the algorithm,then the algorithm was implemented in the low-cost MRAG AHRS, and performance of the improved algorithm was compared with that of the extended Kalman filter (EKF) algorithm. The experiment results and analysis show that the improved algorithm can achieve a convergence at the initial time when MTI sensor data is used under dynamic conditions, approximately 4s earlier than the fast complement filter (FCF) algorithm; the calculation precision is ±0.6°, and the initial precision is obviously better than FCF.Furthermore, the hardware test indicates that processing time for the improved algorithm is 0.062 ms, accounting for 1/9 of the EKF algorithm, with an approximately calculation precision of ±1.3°, which can meet the requirement of fast convergence, high precision and real-time during the attitude measurement.

Aimed at actual problem of low energy of remote sensing image, a local linear image enhancement method of luminance histogram was put forward to improve visual effect of color remote sensing image. Firstly, HSI transformation was performed on color remote sensing image described by RGB model to separate component H, S and I effectively; secondly, traditional histogram equalization was implemented to luminance I component and gained equalized gray level mapping curve; then, by taking image gradient as objective function, the location of optimum linear break point were determined and linear processing was conducted to mapping curve within dynamic range at low side of gray level and gained local linear gray level mapping curve; finally, new gray level mapping curve was adopted to enhance image. Experimental result of Himawari-8 true color image enhancement shows that after local linear enhancement of luminance histogram, level gradient of pixel increases from 73 to 147, and with traditional RGB domain histogram equalization, it only increases to 123, with HSI domain histogram equalization, it increases to 134, and information entropy of image increases from 5.87 to 6.63, so it can be conclusion that the proposed algorithm is superior than other two algorithms in all aspects. The method improves visual effect of color remote sensing image effectively and improves identification capability of image to different objectives.

As the traditional segmentation algorithms are difficult to realize accurate segmentation for high resolution multispectral image , this paper proposed a kind of fuzzy clustering segmentation algorithm of multispectral image on the basis of Gaussian mixture model(GMM). GMM was adopted to define the dissimilarity measure of pixels to the clusters.As the proposed algorithm has the ability of high-precision fitting data statistics distribution,it can effectively eliminate the negative impact of noise on segmentation results. Hidden Markov Random Field (HMRF) was brought in to define prior probability of neighborhood relationship simultaneously,then the prior probability was used as weight of each Gaussian component and parameter to control cluster scale in Kullback-Leibler (KL), so the robustness of algorithm to remote sensing image at complex scene was increased and segmentation accuracy of algorithm was further improved. Qualitative and quantitative analysis were conducted on segmentation result of simulated image and high resolution multispectral image. Experimental result shows that the total accuracy of simulated image exceeds 96.8%, which verifies that algorithm mentioned has detailed information keeping capacity when performing segmentation to high resolution multispectral image and verifies effectiveness and feasibility of algorithm. The algorithm can realize accurate segmentation of the high resolution multispectral image.

When shipboard photoelectric tracking equipment traces target more than 100 km away from it, because of disturbance of barrier, target is often lost from field of view.Under this condition, memory track algorithm shall be adopted to predict location of target at future time to re-find target. Conventional CA and CV models ignore residual error when predicting target, and memory track time is short, which causes insufficient accuracy of target predicted. In consideration of above problems, Kalman target prediction model was put forward to lengthen memory track time. Firstly, this paper derived boat-swing velocity under deck coordinate system from ship-earth coordinate transformation formula, performed feedforward to velocity loop of servo control system to guarantee self-stabilization of optical axis and improve tracking accuracy simultaneously; secondly, CA, CV and Kalman target prediction models were described; finally, 2-dimension position information relationship between memory tracking of 3 kinds of target prediction models and real-time radar guidance location was mainly discussed. Test results show that compared with traditional CA and CV models, target prediction time of proposed method is improved more than an order of magnitudes, that's because Kalman target prediction model is introduced in this paper. The problem in project that tracking accuracy of shipboard photoelectric tracking equipment will be low and memory tracking time will be short when it is affected by boat-swing is solved.

A detection method based on Tensor Low-Rank Representation (TLRR) and spatial-temporal sparsity decomposition was proposed to detect foreground targets in video sequences. Since foreground in video sequence has sparsity inherently besides spatially continuous and temporally continuous, this paper put forward spatial-temporal sparsity-inducing norm to perform deep research on property of foreground. Original video was decomposed in tensor representation formed by tensor low-rank representation method, line information and column information of original data were fully used, and two-stage decomposition of original background and foreground was generalized to three-stage decomposition of background, foreground and noises. Optimization solution was performed with Inexact Augmented Lagrange Multiplier (IALM) method.Verification and comparison experiment was established, and further research experiment was performed to research how ρ affecting performance of algorithm. Experimental results show that the method can detect moving foreground in video effectively and improve accuracy when compared with existing methods.

An improved dynamic programming method based on position predication was proposed in the paper to quickly detect dim and small debris from the space-based observed images on GEO band. Firstly, after analyzing the observed data, we found that different GEO debris have same movement velocity in images, after further data fitting, we obtained a mapping model between the velocity of image debrits and sub-star latitude of observation satellite and proposed a method to estimate the debris velocity in space-based observation images on the GEO band, at last, debris position was predicted by estimating velocity,then position information weight was applied in traditional dynamic programming recursive equation, and the object searching range was obtained based on position prediction,resulting in the number of object status in the recursive equation were reduced. Measured data verified that fitting deviation of velocity mapping model was within 1pixel. We selected the measured data within typical observation period for test and the results show that the detection time taken by proposed method has been reduced by more than 90% as compared with traditional dynamic programming methods, and the virtual scenery rate has also been reduced by more than 5.9%.It can be conclusion that the method is suitable for detection of dim and small debris from the space-based observation images on GEO band.

Traditional ultrasonic echo time-delay estimation algorithm is studied in the background of Gauss Noise, while in actual working condition ultrasonic echo includes not only Gauss Noise but also impulsive noise (α noise with stable distribution), which will invalidate traditional algorithms. In actual application, in order to solve the above problem, a new ultrasonic echo time-delay estimation method under mixed noise, especially the background containing α noises, was proposed, called time delay estimation algorithm with normalized cyclic correlation. Firstly, a brief introduction to theory of such normalized cyclic correlation algorithm was given and a theoretical derivation analysis on such algorithm was conducted.Then,combined with simulation analysis,the performance of proposed algorithm and traditional cyclic cross-correlation algorithm were compared under the same condition. At last, the estimation performance of such normalized cyclic correlation time delay estimation algorithm was analyzed under different singal-noise ratios. Contrast test indicates that when α approaches to 1, the cyclic cross-correlation algorithm is unable to estimate the time delay, while the normalized cyclic cross-correlation algorithm still maintains the deviation at 0.4 μs; and under -10dB SNR, the time delay estimated by normalized cyclic cross-correlation algorithm is also maintained within 10 μs. The normalized cyclic cross-correlation algorithm proposed in the article is able to make accurate estimation of time delay of ultrasonic echo under the background of mixed noise, especially the one contains α noise, which is an incomparable advantage that traditional algorithm is unable to counteract.