the close photogrammetric 3-D coordinate measurement is a newmeasuring technology in the fields of the coordinate measurementmachine (CMM) in recent years. In this method, we usually place sometargets on the measured ...the close photogrammetric 3-D coordinate measurement is a newmeasuring technology in the fields of the coordinate measurementmachine (CMM) in recent years. In this method, we usually place sometargets on the measured object and take image of targets to determinethe object coordinate. The subpixel location of target image plays animportant role in high accuracy 3-D coordinate measuring procedure.In this paper, some subpixel location methods are reviewed and somefactors which affect location precision are analyzed.展开更多
In order to measure the range, angle, and Doppler frequency of the target without any synchronization in the bistatic radar, a novel complete parameter estimation method based on separability of a pair of Linear Frequ...In order to measure the range, angle, and Doppler frequency of the target without any synchronization in the bistatic radar, a novel complete parameter estimation method based on separability of a pair of Linear Frequency Modulation (LFM) signal is presented. The Doppler fre-quency is measured by the time difference between two peak positions corresponding to the positive and the negative LFM return signal respectively. Direction Of Departures (DODs) and Direction Of Arrivals (DOAs) of the target are estimated by constructing a special eigenmatrix in which the es-timated angles can be extracted from the eigenvalue or the eigenvector. The target position can be located in the presence of the estimated DODs, DOAs and the signal delay difference between the echo and the directive wave signal in Multiple Input Multiple Output (MIMO) bistatic radar without any synchronization. The correctness and effectiveness of the proposed method are verified by the computer simulation.展开更多
Target tracking is one typical application of visual servoing technology. It is still a difficult task to track high speed target with current visual servo system. The improvement of visual servoing scheme is strongly...Target tracking is one typical application of visual servoing technology. It is still a difficult task to track high speed target with current visual servo system. The improvement of visual servoing scheme is strongly required. A position-based visual servo parallel system is presented for tracking target with high speed. A local Frenet frame is assigned to the sampling point of spatial trajectory. Position estimation is formed by the differential features of intrinsic geometry, and orientation estimation is formed by homogenous transformation. The time spent for searching and processing can be greatly reduced by shifting the window according to features location prediction. The simulation results have demonstrated the ability of the system to track spatial moving object.展开更多
In this paper, a multi-static system working in an active way is made up of ionospheric oblique backscatter sounding system （IOBSS） and two separate receiving stations, which adopts discontinuous wave mechanism. We ...In this paper, a multi-static system working in an active way is made up of ionospheric oblique backscatter sounding system （IOBSS） and two separate receiving stations, which adopts discontinuous wave mechanism. We have advanced a new model that contains skywave condition to locate over-the-horizon targets. We use a single quasi-parabolic （QP） ionosphere model and an analytic ray-tracing program to obtain the coordinate registration （CR） index, which changes skywave group range to ground range. Also, IOBSS and other two receiving stations use this distance information to locate the target which is far away from the system. The analytic expression for the geometric dilution of precision （GDOP） under different station deployments are obtained, which shows GDOP is influenced by the system measurement precision, the stations＇ coordinates, and CR index. By computer simulation, we find that GDOP of isosceles right triangle deployment is smaller than that of line deployment and location precision will be improved with increasing base line length. The results indicate that this model is practicable with an acceptable range of error （less than 500 m under certain conditions in this paper）.展开更多
This paper proposes a tracking-based target locating algorithm to locate a target moving in a geographical region under the surveillance of a wireless sensor network. This algorithm first finds a sensor node that has ...This paper proposes a tracking-based target locating algorithm to locate a target moving in a geographical region under the surveillance of a wireless sensor network. This algorithm first finds a sensor node that has detected the target, and then uses local messages between neighboring nodes to track the trail of the target. The authors implement this algorithm and compare it with an optimized flood-based target locating algorithm. Simulation results show that this algorithm effectively reduces the message transmission, conserves energy and consequently enhances the practicability of resource-limited wireless sensor networks.展开更多
An iteration method for correcting the target coordinates determined by a locating system with a Cartesian array is reported. Under the complex hydrological condition, the method can give the target position not only ...An iteration method for correcting the target coordinates determined by a locating system with a Cartesian array is reported. Under the complex hydrological condition, the method can give the target position not only accurately but also quickly. The preliminary experimental results show that the correction is effective. An application of the method has been completed.展开更多
A principle for choosing the coherent integration number and an improved Doppler beam sharpening(DBS)imaging algorithm for mechanic scanning radar are pre-sented in this paper.By compensating the range migration in wi...A principle for choosing the coherent integration number and an improved Doppler beam sharpening(DBS)imaging algorithm for mechanic scanning radar are pre-sented in this paper.By compensating the range migration in wideband airborne mechanic scanning radar,the proposed DBS imaging algorithm can efficiently improve the resolu-tion of a DBS image.In addition,based on the characteristic that the echo from the moving target will be modulated by the antenna pattern,a novel method used to locate the mov-ing target is also presented,which begins with the sub-aperture moving target detection followed by the sliding window detection.Proper location can be achieved by using this method.Finally,the results on real radar data are pro-vided to demonstrate the effectiveness of these proposed methods.展开更多
文摘the close photogrammetric 3-D coordinate measurement is a newmeasuring technology in the fields of the coordinate measurementmachine (CMM) in recent years. In this method, we usually place sometargets on the measured object and take image of targets to determinethe object coordinate. The subpixel location of target image plays animportant role in high accuracy 3-D coordinate measuring procedure.In this paper, some subpixel location methods are reviewed and somefactors which affect location precision are analyzed.
基金Supported by National Natural Science Foundation of China (No. 60601016)
文摘In order to measure the range, angle, and Doppler frequency of the target without any synchronization in the bistatic radar, a novel complete parameter estimation method based on separability of a pair of Linear Frequency Modulation (LFM) signal is presented. The Doppler fre-quency is measured by the time difference between two peak positions corresponding to the positive and the negative LFM return signal respectively. Direction Of Departures (DODs) and Direction Of Arrivals (DOAs) of the target are estimated by constructing a special eigenmatrix in which the es-timated angles can be extracted from the eigenvalue or the eigenvector. The target position can be located in the presence of the estimated DODs, DOAs and the signal delay difference between the echo and the directive wave signal in Multiple Input Multiple Output (MIMO) bistatic radar without any synchronization. The correctness and effectiveness of the proposed method are verified by the computer simulation.
基金This project is supported by National Electric Power Corporation Foundation of China(No.SPKJ010-27).
文摘Target tracking is one typical application of visual servoing technology. It is still a difficult task to track high speed target with current visual servo system. The improvement of visual servoing scheme is strongly required. A position-based visual servo parallel system is presented for tracking target with high speed. A local Frenet frame is assigned to the sampling point of spatial trajectory. Position estimation is formed by the differential features of intrinsic geometry, and orientation estimation is formed by homogenous transformation. The time spent for searching and processing can be greatly reduced by shifting the window according to features location prediction. The simulation results have demonstrated the ability of the system to track spatial moving object.
基金Supported by the National High Technology Research and Development Program of China (863 Program) (2009AAXXX1302)
文摘In this paper, a multi-static system working in an active way is made up of ionospheric oblique backscatter sounding system （IOBSS） and two separate receiving stations, which adopts discontinuous wave mechanism. We have advanced a new model that contains skywave condition to locate over-the-horizon targets. We use a single quasi-parabolic （QP） ionosphere model and an analytic ray-tracing program to obtain the coordinate registration （CR） index, which changes skywave group range to ground range. Also, IOBSS and other two receiving stations use this distance information to locate the target which is far away from the system. The analytic expression for the geometric dilution of precision （GDOP） under different station deployments are obtained, which shows GDOP is influenced by the system measurement precision, the stations＇ coordinates, and CR index. By computer simulation, we find that GDOP of isosceles right triangle deployment is smaller than that of line deployment and location precision will be improved with increasing base line length. The results indicate that this model is practicable with an acceptable range of error （less than 500 m under certain conditions in this paper）.
文摘This paper proposes a tracking-based target locating algorithm to locate a target moving in a geographical region under the surveillance of a wireless sensor network. This algorithm first finds a sensor node that has detected the target, and then uses local messages between neighboring nodes to track the trail of the target. The authors implement this algorithm and compare it with an optimized flood-based target locating algorithm. Simulation results show that this algorithm effectively reduces the message transmission, conserves energy and consequently enhances the practicability of resource-limited wireless sensor networks.
文摘An iteration method for correcting the target coordinates determined by a locating system with a Cartesian array is reported. Under the complex hydrological condition, the method can give the target position not only accurately but also quickly. The preliminary experimental results show that the correction is effective. An application of the method has been completed.
文摘A principle for choosing the coherent integration number and an improved Doppler beam sharpening(DBS)imaging algorithm for mechanic scanning radar are pre-sented in this paper.By compensating the range migration in wideband airborne mechanic scanning radar,the proposed DBS imaging algorithm can efficiently improve the resolu-tion of a DBS image.In addition,based on the characteristic that the echo from the moving target will be modulated by the antenna pattern,a novel method used to locate the mov-ing target is also presented,which begins with the sub-aperture moving target detection followed by the sliding window detection.Proper location can be achieved by using this method.Finally,the results on real radar data are pro-vided to demonstrate the effectiveness of these proposed methods.
