Submit Manuscript
Peer Review
Editor Work2013 Vol. 2, No. 4
Previous Issue
2013, 2(4): 389-399.
Abstract
931KB
Global Navigation Satellite System (GNSS), has a significant impact on all areas of human activity, not only can provide users with shared global navigation, position and timing information, but also can provide a L-band microwave signal source of long term stability and high temporal-spatial resolution. In recent years, development of the navigation satellite remote sensing applications using GNSS as a external illuminator, it has been forming a new Global Navigation Satellite System METeorology (GNSS/MET), of which Global Navigation Satellite System-Reflection (GNSS-R) signals remote sensing technology is rising. It could be considered as a non-cooperative artificial illuminator, bistatic (multi-static) radar system, and has the advantages of both passive and active remote sensing. Then it gets more and more peoples attention and favor, and broadening into Atmosphere -ocean and land surface remote sensing fields. However, the address of this technology is very messy at home and abroad, and not able to accurately express its special meaning. This article attempts to give a new term: Exogenous-Aided Remote Sensing (EARS) for discussion.
Global Navigation Satellite System (GNSS), has a significant impact on all areas of human activity, not only can provide users with shared global navigation, position and timing information, but also can provide a L-band microwave signal source of long term stability and high temporal-spatial resolution. In recent years, development of the navigation satellite remote sensing applications using GNSS as a external illuminator, it has been forming a new Global Navigation Satellite System METeorology (GNSS/MET), of which Global Navigation Satellite System-Reflection (GNSS-R) signals remote sensing technology is rising. It could be considered as a non-cooperative artificial illuminator, bistatic (multi-static) radar system, and has the advantages of both passive and active remote sensing. Then it gets more and more peoples attention and favor, and broadening into Atmosphere -ocean and land surface remote sensing fields. However, the address of this technology is very messy at home and abroad, and not able to accurately express its special meaning. This article attempts to give a new term: Exogenous-Aided Remote Sensing (EARS) for discussion.
2013, 2(4): 400-405.
In this study, the concept and system of a distributed POS are discussed. Based on the different operation modes, the principle technical parameters and requirements for optical camera and imaging radar with multiple subarray antennas are presented. Further, technical approaches to obtain precise position and attitude information for the POS are investigated, and some possible applications are proposed.
In this study, the concept and system of a distributed POS are discussed. Based on the different operation modes, the principle technical parameters and requirements for optical camera and imaging radar with multiple subarray antennas are presented. Further, technical approaches to obtain precise position and attitude information for the POS are investigated, and some possible applications are proposed.
2013, 2(4): 406-421.
In recent years, Internal Waves (IWs) detection in Synthetic Aperture Radar (SAR) image has received considerable attentions in the area of marine remote sensing and has already become one of the most important marine applications of SAR. Typical research results at home and abroad are reviewed. Three areas of researches are introduced and summarized, including parameter inversion method of IWs, the effect of different SAR parameter and wind field conditions on IWs imaging, the 2-dimentional SAR imaging simulation of IWs.
In recent years, Internal Waves (IWs) detection in Synthetic Aperture Radar (SAR) image has received considerable attentions in the area of marine remote sensing and has already become one of the most important marine applications of SAR. Typical research results at home and abroad are reviewed. Three areas of researches are introduced and summarized, including parameter inversion method of IWs, the effect of different SAR parameter and wind field conditions on IWs imaging, the 2-dimentional SAR imaging simulation of IWs.
2013, 2(4): 422-429.
Radar low-elevation estimation performance in the VHF band is severely influenced in the presence of multipath. To deal with this problem, this study first analyzes general MUSIC (MUltiple SIgnal Classification) and other algorithms, pointing out that the essential effectiveness of these algorithms is a weighting of the basic spectrum searching formula, which inhibits large spectrum values produced by a small angle. On this basis, this paper subsequently presents an elevation-estimating model via a general MUSIC algorithm and a new lowelevation angle estimation method, which utilizes a proper weight. Compared with existing methods, the new method has a higher probability of success and better performance. Simulation results verify the validity and correctness of this method and model.
Radar low-elevation estimation performance in the VHF band is severely influenced in the presence of multipath. To deal with this problem, this study first analyzes general MUSIC (MUltiple SIgnal Classification) and other algorithms, pointing out that the essential effectiveness of these algorithms is a weighting of the basic spectrum searching formula, which inhibits large spectrum values produced by a small angle. On this basis, this paper subsequently presents an elevation-estimating model via a general MUSIC algorithm and a new lowelevation angle estimation method, which utilizes a proper weight. Compared with existing methods, the new method has a higher probability of success and better performance. Simulation results verify the validity and correctness of this method and model.
2013, 2(4): 430-438.
For passive radar, long integration time is used to achieve high processing gain to detect weak target. But range migration and Doppler expansion may occur for high-speed targets. Keystone transform can be used to rectify range migration introduced by radial-speed. But tangential-speed may still lead to Doppler expansion, which entails a loss of integration gain. In this paper, signal model is presented to analyze the reason for Doppler expansion. Then, a Doppler expansion compensation method is introduced based on RSPWVD-Hough transform for multi-target scenario. Simulation results show that the proposed method can compensate the energy loss caused by Doppler expansion for multi-target scene, and it achieves good performance. The proposed method is also effective for weak targets, which means it can improve the detection ability of weak target in passive radar systems.
For passive radar, long integration time is used to achieve high processing gain to detect weak target. But range migration and Doppler expansion may occur for high-speed targets. Keystone transform can be used to rectify range migration introduced by radial-speed. But tangential-speed may still lead to Doppler expansion, which entails a loss of integration gain. In this paper, signal model is presented to analyze the reason for Doppler expansion. Then, a Doppler expansion compensation method is introduced based on RSPWVD-Hough transform for multi-target scenario. Simulation results show that the proposed method can compensate the energy loss caused by Doppler expansion for multi-target scene, and it achieves good performance. The proposed method is also effective for weak targets, which means it can improve the detection ability of weak target in passive radar systems.
2013, 2(4): 439-444.
For oversized front distributed phased array radar, the conventional phased array radar calibration algorithm can not work. This paper presents the combination of self-calibration and cross-calibration algorithm. Analyzed the error sources of the oversized front distributed phased array radar. Established the error model of the oversized front distributed phased array radar. Elaborated the self-calibration and cross-calibration principles and methods. This method is extended to the phase array radar from units. Finally, we carry out the self-intersecting phase calibration simulation experiments. The simulation results show that the algorithm can significantly improve the oversized front distributed phased array radar sidelobe level.
For oversized front distributed phased array radar, the conventional phased array radar calibration algorithm can not work. This paper presents the combination of self-calibration and cross-calibration algorithm. Analyzed the error sources of the oversized front distributed phased array radar. Established the error model of the oversized front distributed phased array radar. Elaborated the self-calibration and cross-calibration principles and methods. This method is extended to the phase array radar from units. Finally, we carry out the self-intersecting phase calibration simulation experiments. The simulation results show that the algorithm can significantly improve the oversized front distributed phased array radar sidelobe level.
2013, 2(4): 445-453.
As an important mode in airborne radar systems, Wide Area Surveillance Ground Moving Target Indication (WAS-GMTI) mode has the ability of monitoring a large area in a short time, and then the detected moving targets can be located quickly. However, in real environment, many factors introduce considerable errors into the location of moving targets. In this paper, a fast location method based on the characteristics of the moving targets in WAS-GMTI mode is utilized. And in order to improve the location performance, those factors that introduce location errors are analyzed and moving targets are relocated. Finally, the analysis of those factors is proved to be reasonable by simulation and real data experiments.
As an important mode in airborne radar systems, Wide Area Surveillance Ground Moving Target Indication (WAS-GMTI) mode has the ability of monitoring a large area in a short time, and then the detected moving targets can be located quickly. However, in real environment, many factors introduce considerable errors into the location of moving targets. In this paper, a fast location method based on the characteristics of the moving targets in WAS-GMTI mode is utilized. And in order to improve the location performance, those factors that introduce location errors are analyzed and moving targets are relocated. Finally, the analysis of those factors is proved to be reasonable by simulation and real data experiments.
2013, 2(4): 454-460.
In this paper, an observability analysis of sensor bias based on the track-independent estimation model is presented. Observability analysis is a prerequisite for developing a systematic error estimation model. Therefore, an observability matrix is adopted to study the observability and observability degree of sensor bias. Initially, based on the track-independent model, both state transformation and measurement models of sensor bias are built in two dimensions to construct the observability matrix. Then, the observability of the sensor bias is studied by judging the singularity of the observability matrix. Further, the mathematical expression for the degree of observability is presented. Finally, several typical simulations to demonstrate the effect of degree of observability on the estimation accuracy of sensor bias and the effects of sensor location and target motion on the observability and observability degree of sensor bias are provided.
In this paper, an observability analysis of sensor bias based on the track-independent estimation model is presented. Observability analysis is a prerequisite for developing a systematic error estimation model. Therefore, an observability matrix is adopted to study the observability and observability degree of sensor bias. Initially, based on the track-independent model, both state transformation and measurement models of sensor bias are built in two dimensions to construct the observability matrix. Then, the observability of the sensor bias is studied by judging the singularity of the observability matrix. Further, the mathematical expression for the degree of observability is presented. Finally, several typical simulations to demonstrate the effect of degree of observability on the estimation accuracy of sensor bias and the effects of sensor location and target motion on the observability and observability degree of sensor bias are provided.
2013, 2(4): 461-465.
The Compound-Gaussian (CG) distribution is widely used for modeling the non-Gaussian clutter, and its texture component describes the non-Gaussian properties of clutter. In this paper, a CG model with an inverse Gaussian texture distribution is proposed, called Inverse Gaussian Compound Gaussian (IG-CG) distribution, and its distributional properties are derived. The IPIX radar lake-clutter measurements are analyzed, and the results show that the two-parameter IG-CG distribution model fits the real radar data better than single parameter IG-CG distribution model and K distribution model.
The Compound-Gaussian (CG) distribution is widely used for modeling the non-Gaussian clutter, and its texture component describes the non-Gaussian properties of clutter. In this paper, a CG model with an inverse Gaussian texture distribution is proposed, called Inverse Gaussian Compound Gaussian (IG-CG) distribution, and its distributional properties are derived. The IPIX radar lake-clutter measurements are analyzed, and the results show that the two-parameter IG-CG distribution model fits the real radar data better than single parameter IG-CG distribution model and K distribution model.
2013, 2(4): 466-475.
This paper illustrates the full use of an orthogonal decoupling signal model to describe the 3-D construction of polarized electromagnetic waves. The maximum likelihood method and MUSIC algorithm were introduced into the parameter estimation of partially polarized waves. Attitude reference information for an aircraft that was calibrated by an information base station was delivered by polarized electromagnetic waves. Through receiving and processing the information of the aircraft, a single electromagnetic vector sensor can acquire the aircraft attitude in a geographic coordinate system. Differing from the triangle calculation method which relies on a multi-point measurement, the proposed method only needs a base station signal and a single receiver on the motion platform to realize the posture perception of aircraft. It can therefore serve as a substitute for aircraft attitude navigation and aircraft heading navigation. The introduction of the motion platform attitude estimation algorithm provides a technology support for engineering applications.
This paper illustrates the full use of an orthogonal decoupling signal model to describe the 3-D construction of polarized electromagnetic waves. The maximum likelihood method and MUSIC algorithm were introduced into the parameter estimation of partially polarized waves. Attitude reference information for an aircraft that was calibrated by an information base station was delivered by polarized electromagnetic waves. Through receiving and processing the information of the aircraft, a single electromagnetic vector sensor can acquire the aircraft attitude in a geographic coordinate system. Differing from the triangle calculation method which relies on a multi-point measurement, the proposed method only needs a base station signal and a single receiver on the motion platform to realize the posture perception of aircraft. It can therefore serve as a substitute for aircraft attitude navigation and aircraft heading navigation. The introduction of the motion platform attitude estimation algorithm provides a technology support for engineering applications.
2013, 2(4): 476-480.
The quadrature signal generator is widely used in devices such as the quadrature modulator and image rejection frequency converter. An RC polyphase network is commonly used as a quadrature signal generator because of its simple structure and perfect linear performance. This study derives explicit transfer functions for the RC polyphase network based on the complex signal properties and the matrix theory. Moreover, build-related parameters are determined to analyze the I/Q amplitude and phase balance characteristic of the RC polyphase network, thus providing a theoretical guideline for the design of a high-balance quadrature signal generator.
The quadrature signal generator is widely used in devices such as the quadrature modulator and image rejection frequency converter. An RC polyphase network is commonly used as a quadrature signal generator because of its simple structure and perfect linear performance. This study derives explicit transfer functions for the RC polyphase network based on the complex signal properties and the matrix theory. Moreover, build-related parameters are determined to analyze the I/Q amplitude and phase balance characteristic of the RC polyphase network, thus providing a theoretical guideline for the design of a high-balance quadrature signal generator.
2013, 2(4): 481-491.
Synthetic Aperture Radar (SAR) image processing requires huge computation amount. Traditionally, this task runs on the workstation or server based on Central Processing Unit (CPU) and is rather time-consuming, hence real-time processing of SAR data is impossible. Based on Compute Unified Device Architecture (CUDA) technology, a new plan of SAR imaging algorithm operated on NVIDIA Graphic Processing Unit (GPU) is proposed. The new proposal makes it possible that the data processing procedure and CPU/GPU data exchanging execute concurrently, especially when SAR data size exceeds total GPU global memory size. Multi-GPU is suitably supported by the new proposal and all of computational resources are fully exploited. It is shown by experiment on NVIDIA K20C and INTEL E5645 that the proposed solution accelerates SAR data processing by tens of times. Consequently, the GPU based SAR processing system with the proposed solution embedded is much more power saving and portable, which makes it qualified to be a real-time SAR data processing system. Experiment shows that SAR data of 36 Mega points can be processed in real-time per second by K20C with the new solution equipped.
Synthetic Aperture Radar (SAR) image processing requires huge computation amount. Traditionally, this task runs on the workstation or server based on Central Processing Unit (CPU) and is rather time-consuming, hence real-time processing of SAR data is impossible. Based on Compute Unified Device Architecture (CUDA) technology, a new plan of SAR imaging algorithm operated on NVIDIA Graphic Processing Unit (GPU) is proposed. The new proposal makes it possible that the data processing procedure and CPU/GPU data exchanging execute concurrently, especially when SAR data size exceeds total GPU global memory size. Multi-GPU is suitably supported by the new proposal and all of computational resources are fully exploited. It is shown by experiment on NVIDIA K20C and INTEL E5645 that the proposed solution accelerates SAR data processing by tens of times. Consequently, the GPU based SAR processing system with the proposed solution embedded is much more power saving and portable, which makes it qualified to be a real-time SAR data processing system. Experiment shows that SAR data of 36 Mega points can be processed in real-time per second by K20C with the new solution equipped.
2013, 2(4): 492-498.
The measurement inaccuracies of Inertial Measurement Unit/Global Positioning System (IMU/GPS) as well as the positioning error of the target may contribute to the residual uncompensated motion errors in the MOtion COmpensation (MOCO) approach based on the measurement of IMU/GPS. Aiming at the effects of target positioning error on MOCO for airborne interferometric SAR, the paper firstly deduces a mathematical model of residual motion error bring out by target positioning error under the condition of squint. And the paper analyzes the effects on the residual motion error caused by system sampling delay error, the Doppler center frequency error and reference DEM error which result in target positioning error based on the model. Then, the paper discusses the effects of the reference DEM error on the interferometric SAR image quality, the interferometric phase and the coherent coefficient. The research provides theoretical bases for the MOCO precision in signal processing of airborne high precision SAR and airborne repeat-pass interferometric SAR.
The measurement inaccuracies of Inertial Measurement Unit/Global Positioning System (IMU/GPS) as well as the positioning error of the target may contribute to the residual uncompensated motion errors in the MOtion COmpensation (MOCO) approach based on the measurement of IMU/GPS. Aiming at the effects of target positioning error on MOCO for airborne interferometric SAR, the paper firstly deduces a mathematical model of residual motion error bring out by target positioning error under the condition of squint. And the paper analyzes the effects on the residual motion error caused by system sampling delay error, the Doppler center frequency error and reference DEM error which result in target positioning error based on the model. Then, the paper discusses the effects of the reference DEM error on the interferometric SAR image quality, the interferometric phase and the coherent coefficient. The research provides theoretical bases for the MOCO precision in signal processing of airborne high precision SAR and airborne repeat-pass interferometric SAR.
2013, 2(4): 499-506.
It has important meaning for Synthetic Aperture Radar (SAR) interpretation to estimate parameters from measured SAR data and visualize the SAR imagery. For the linearity of IFFT, single scattering center can be individually imaged adaptively to form an overall image. Thus, the side effects of side lobes and windowing can be decreased and the quality of the SAR imagery can be improved. The efficiency of the method is confirmed by the test based on the simulated data.
It has important meaning for Synthetic Aperture Radar (SAR) interpretation to estimate parameters from measured SAR data and visualize the SAR imagery. For the linearity of IFFT, single scattering center can be individually imaged adaptively to form an overall image. Thus, the side effects of side lobes and windowing can be decreased and the quality of the SAR imagery can be improved. The efficiency of the method is confirmed by the test based on the simulated data.
微信 | 公众平台 
