Target detection is an important research content in the radar field.At present,efforts are being made to optimize the precision of detection information.In this paper,we use the high pulse repetition frequency(HPRF)t...Target detection is an important research content in the radar field.At present,efforts are being made to optimize the precision of detection information.In this paper,we use the high pulse repetition frequency(HPRF)transmission method and orthogonal biphase coded signals in each pulse to avoid velocity ambiguity and range ambiguity of radar detection.In addition,We also apply Walsh matrix and genetic algorithm(GA)to generate satisfying orthogonal biphase coded signals with low auto-correlation sidelobe peak and cross-correlation peak,which make the results more accurate.In a radar receiver,data rearrangement of echo signals is performed,and then pulse compression and moving target detection(MTD)are utilized to get the final velocity and range information of a target without velocity ambiguity and range ambiguity.Besides,a small transmitting pulse time width is adopted to reduce the working blind area,and two different high pulse repetition frequencies(HPRFs)are adopted to solve the problem of range eclipse.Simulation results finally prove the effectiveness and feasibility of the proposed method.展开更多
A new approach is proposed which can satisfy the range ambiguity requirement while keep the antenna width not to be enlarged and get the high quality image also. Here the chirp slope of the transmitted linear frequenc...A new approach is proposed which can satisfy the range ambiguity requirement while keep the antenna width not to be enlarged and get the high quality image also. Here the chirp slope of the transmitted linear frequency modulated pulses is reversed alternately. Therefore, during the range compression significant portion of the ambiguous return which is due to the mismatching with the signal reference function is suppressed. The suggested method provides significant improvement in range ambiguity ratio and can be utilized in attaining wider swath.展开更多
Modified implementation architecture for sinusoidal frequency modulation is introduced to extract the range information from the received radar echo. Range ambiguity problem arises because the range is calculated from...Modified implementation architecture for sinusoidal frequency modulation is introduced to extract the range information from the received radar echo. Range ambiguity problem arises because the range is calculated from the estimated phase of the received signal which is wrapped into (0, 2π]. By integrating Doppler frequency shifts, the variation of range can be estimated and used as an auxiliary information to help eliminating the corresponding range ambiguity. The performance of the new technique is evaluated by simulations. The results show that this technique is robust to sever phase noise and can be used effectively for ambiguity elimination of the modified sinusoidal frequency modulated continuous wave radar.展开更多
Space-time coding radar has been recently proposed and investigated.It is a radar framework which can perform transmit beamforming at the receiver.However,the range resolution decreases when the number of the transmit...Space-time coding radar has been recently proposed and investigated.It is a radar framework which can perform transmit beamforming at the receiver.However,the range resolution decreases when the number of the transmit element increases.A subarray-based space-time coding(sub-STC)radar is explored to alleviate the range resolution reduction.For the proposed radar configuration,an identical waveform is transmitted and it introduces a small time offset in different subarrays.The multidimensional ambiguity function of sub-STC radar is defined by considering resolutions in multiple domains including the range,Doppler,angle and probing direction.Analyses on properties of the multi-dimensional ambiguity function of the sub-STC radar with regard to the spatial coverage,resolution performance and low sidelobes are also given.Results reveal that the range resolution and low sidelobes performance are improved with the proposed approach.展开更多
The problems of joint adaptive waveform design and baseline range design for bistatic radar to maximize the practical radar resolution were considered.Distinguishing from the conventional ambiguity function(AF)-based ...The problems of joint adaptive waveform design and baseline range design for bistatic radar to maximize the practical radar resolution were considered.Distinguishing from the conventional ambiguity function(AF)-based resolution which is only related with the transmitted waveform and bistatic geometry and could be regarded as the potential resolution of a bistatic radar system,the practical resolution involves the effect of waveform,signal-to-noise ratio(SNR)as well as the measurement model.Thus,it is more practical and will have further significant application in target detection and tracking.The constraint optimization procedure of joint adaptive waveform design and baseline range design for maximizing the practical resolution of bistatic radar system under dynamic target scenario was devised.Simulation results show that the range and velocity resolution are enhanced according to the adaptive waveform and bistatic radar configuration.展开更多
Target vdocity and acceleration are two of the most important features for identification of warheads and decoys in ballistic missile defense phased array radar systems. Velocity compensation is also the necessary ste...Target vdocity and acceleration are two of the most important features for identification of warheads and decoys in ballistic missile defense phased array radar systems. Velocity compensation is also the necessary step for one-dimensional range profile imaging. According to the high-vdocity characteristics of ballistic objects and the low data rate of phased array radars with multiple target tracking, a fine spectral line digital velocity tracking frame is presented and a new method is developed to extract velocity error and resolve the velocity ambiguity in the measurement loop. Simulation results demonstrate the effectiveness of the proposed technique.展开更多
When the Airborne Early Warning(AEW) radar transmits medial or high Pulse Repetitive Frequency(PRF) signal,the range ambiguity occurs.The clutter of short-range clutter has serious range dependence problem for non-Sid...When the Airborne Early Warning(AEW) radar transmits medial or high Pulse Repetitive Frequency(PRF) signal,the range ambiguity occurs.The clutter of short-range clutter has serious range dependence problem for non-Side Looking Airborne Radar(non-SLAR).As a result,the clutter plus noise covariance matrix can not be estimated correctly,and the performance of clutter suppression obtained by Space-Time Adaptive Processing(STAP) degrades greatly.The uniform linear array has not elevation degrees;therefore,the short-range clutter can not be suppressed directly.A short-range clutter suppression method is proposed.The method first estimate the elevation angles of the ambiguous short-range gate,then eliminates short-range clutter by space time interpolation and adds moving target protection in the procedure.This method can suppress the short-range clutter well.Simulation results show the validity of the method.展开更多
Radial velocity estimation used in wide-band radar systems is investigated.By analyzing the signal of cross-correlation output of adjacent echoes,it is found that the frequency and phase of the cross-correlation outpu...Radial velocity estimation used in wide-band radar systems is investigated.By analyzing the signal of cross-correlation output of adjacent echoes,it is found that the frequency and phase of the cross-correlation output are related to the target’s radial velocity.Since the precision of the phase estimation is higher than that of the frequency,a phase-based velocity estimator is proposed.However,the ambiguity problem exists in the phase estimators,and thus the estimation of the cross-correlation of adjacent echoes(CCAE)is used to calculate the ambiguity number.The root-mean-square-error(RMSE)of the proposed estimator is derived.Simulation results show that the performance of the proposed method is better than that of the frequency-based estimator.展开更多
机载雷达下视工作面临严重的地海杂波,雷达平台运动造成杂波多普勒频率严重扩散,将微弱目标完全淹没。空时自适应处理(space time adaptive processing,STAP)技术通过联合多天线脉冲的接收信号,能够有效地抑制杂波,实现运动目标检测。...机载雷达下视工作面临严重的地海杂波,雷达平台运动造成杂波多普勒频率严重扩散,将微弱目标完全淹没。空时自适应处理(space time adaptive processing,STAP)技术通过联合多天线脉冲的接收信号,能够有效地抑制杂波,实现运动目标检测。对于非正侧视阵列高速平台雷达,杂波距离依赖和距离模糊严重制约着目标检测性能。基于多载频频控阵,通过发射一组载频不同的正交信号,在杂波回波中,获得新的发射维自由度,并根据不同模糊在发射维的差异分离各模糊区域。此外,通过进一步对分离后的近程进行杂波补偿,利用降维STAP实现杂波抑制。仿真结果验证了所提方法的有效性。展开更多
The middle pulse repetition frequency(MPRF)and high pulse repetition frequency(HPRF)modes are widely adopted in airborne pulse Doppler(PD)radar systems,which results in the problem that the range measurement of ...The middle pulse repetition frequency(MPRF)and high pulse repetition frequency(HPRF)modes are widely adopted in airborne pulse Doppler(PD)radar systems,which results in the problem that the range measurement of targets is ambiguous.The existing data processing based range ambiguity resolving methods work well on the condition that the signal-to-noise ratio(SNR)is high enough.In this paper,a multiple model particle flter(MMPF)based track-beforedetect(TBD)method is proposed to address the problem of target detection and tracking with range ambiguous radar in low-SNR environment.By introducing a discrete variable that denotes whether a target is present or not and the discrete pulse interval number(PIN)as components of the target state vector,and modeling the incremental variable of the PIN as a three-state Markov chain,the proposed algorithm converts the problem of range ambiguity resolving into a hybrid state fltering problem.At last,the hybrid fltering problem is implemented by a MMPF-based TBD method in the Bayesian framework.Simulation results demonstrate that the proposed Bayesian approach can estimate target state as well as the PIN simultaneously,and succeeds in detecting and tracking weak targets with the range ambiguous radar.Simulation results also show that the performance of the proposed method is superior to that of the multiple hypothesis(MH)method in low-SNR environment.展开更多
A method, called class multiple signal classification (CMUSIC), is proposed to estimate high-resolution radial velocity in each pulse train (subband, i.e. narrowband) with M pulses based on stepped frequency pulse...A method, called class multiple signal classification (CMUSIC), is proposed to estimate high-resolution radial velocity in each pulse train (subband, i.e. narrowband) with M pulses based on stepped frequency pulse trains (SFPTs) signal. A synthetic ultra-wideband (UWB) high-resolution range profile (HRRP) is then obtained by fast Fourier transform (FFT) processing along the subbands after compensating the range-Doppler coupling and Doppler dispersion with the estimated velocity. Compared with the other methods, CMUSIC has fine performance of velocity estimation at low signal-to-noise ratio (SNR) level. This method also has excellent performance with small Mas long as the requirement, i.e. Mis large than Q, is able to be fulfilled, where Q is the number of targets with different radial velocities. In addition, through a radial velocity resolving, the method can be well suitable for targets moving at high radial velocities, which has significant practical value with considerable progress made in the national defence technology and the advanced vehicles moving at high speed springing up. Simulation results demonstrate the feasibility and effectiveness of the method.展开更多
近年来,随着智能驾驶技术的不断发展,毫米波雷达作为汽车安全控制系统的核心组件受到了广泛关注。时分复用(TDM)多输入多输出(MIMO)调频连续波(FMCW)雷达因具有低硬件成本和高角度分辨率的优势而被广泛应用于汽车雷达,但TDMMIMO在实际...近年来,随着智能驾驶技术的不断发展,毫米波雷达作为汽车安全控制系统的核心组件受到了广泛关注。时分复用(TDM)多输入多输出(MIMO)调频连续波(FMCW)雷达因具有低硬件成本和高角度分辨率的优势而被广泛应用于汽车雷达,但TDMMIMO在实际应用中还存在对运动目标检测易出现速度模糊和角度模糊问题,导致检测误差变大,对于自动驾驶场景存在一定的安全隐患。为解决上述TDM MIMO FMCW雷达存在检测误差高的问题,提出了在多普勒模糊下的FMCW MIMO雷达目标参数估计方法,在不增加额外硬件开销的前提下,可确保算法在低复杂度下提升监测的时效性,解决了速度模糊和相位偏移问题;利用加Kaiser窗FFT波束形成方法对目标角度进行测量,从而得到更精准的目标信息。仿真和实验结果验证了所提方法的有效性。展开更多
基金supported by the Special Science Foundation of Quzhou(2020D007,2021D009).
文摘Target detection is an important research content in the radar field.At present,efforts are being made to optimize the precision of detection information.In this paper,we use the high pulse repetition frequency(HPRF)transmission method and orthogonal biphase coded signals in each pulse to avoid velocity ambiguity and range ambiguity of radar detection.In addition,We also apply Walsh matrix and genetic algorithm(GA)to generate satisfying orthogonal biphase coded signals with low auto-correlation sidelobe peak and cross-correlation peak,which make the results more accurate.In a radar receiver,data rearrangement of echo signals is performed,and then pulse compression and moving target detection(MTD)are utilized to get the final velocity and range information of a target without velocity ambiguity and range ambiguity.Besides,a small transmitting pulse time width is adopted to reduce the working blind area,and two different high pulse repetition frequencies(HPRFs)are adopted to solve the problem of range eclipse.Simulation results finally prove the effectiveness and feasibility of the proposed method.
文摘A new approach is proposed which can satisfy the range ambiguity requirement while keep the antenna width not to be enlarged and get the high quality image also. Here the chirp slope of the transmitted linear frequency modulated pulses is reversed alternately. Therefore, during the range compression significant portion of the ambiguous return which is due to the mismatching with the signal reference function is suppressed. The suggested method provides significant improvement in range ambiguity ratio and can be utilized in attaining wider swath.
基金Sponsored by the Ministerial Level Advanced Research Foundation (323010101-50)
文摘Modified implementation architecture for sinusoidal frequency modulation is introduced to extract the range information from the received radar echo. Range ambiguity problem arises because the range is calculated from the estimated phase of the received signal which is wrapped into (0, 2π]. By integrating Doppler frequency shifts, the variation of range can be estimated and used as an auxiliary information to help eliminating the corresponding range ambiguity. The performance of the new technique is evaluated by simulations. The results show that this technique is robust to sever phase noise and can be used effectively for ambiguity elimination of the modified sinusoidal frequency modulated continuous wave radar.
基金supported by the National Key Research and Development Program of China(2016YFE0200400)the Key R&D Program of Shaanxi Province(2017KW-ZD-12)+1 种基金the Postdoctoral Science Foundation of Shaanxi Provincethe Nature Science Foundation of Shaanxi Province
文摘Space-time coding radar has been recently proposed and investigated.It is a radar framework which can perform transmit beamforming at the receiver.However,the range resolution decreases when the number of the transmit element increases.A subarray-based space-time coding(sub-STC)radar is explored to alleviate the range resolution reduction.For the proposed radar configuration,an identical waveform is transmitted and it introduces a small time offset in different subarrays.The multidimensional ambiguity function of sub-STC radar is defined by considering resolutions in multiple domains including the range,Doppler,angle and probing direction.Analyses on properties of the multi-dimensional ambiguity function of the sub-STC radar with regard to the spatial coverage,resolution performance and low sidelobes are also given.Results reveal that the range resolution and low sidelobes performance are improved with the proposed approach.
基金Project supported by the Program for New Century Excellent Talents in University,ChinaProject(61171133)supported by the National Natural Science Foundation of China+2 种基金Project(11JJ1010)supported by the Natural Science Fund for Distinguished Young Scholars of Hunan Province,ChinaProject(61101182)supported by the National Natural Science Foundation for Young Scientists of ChinaProject(20124307110013)supported by the Doctoral Program of Higher Education of China
文摘The problems of joint adaptive waveform design and baseline range design for bistatic radar to maximize the practical radar resolution were considered.Distinguishing from the conventional ambiguity function(AF)-based resolution which is only related with the transmitted waveform and bistatic geometry and could be regarded as the potential resolution of a bistatic radar system,the practical resolution involves the effect of waveform,signal-to-noise ratio(SNR)as well as the measurement model.Thus,it is more practical and will have further significant application in target detection and tracking.The constraint optimization procedure of joint adaptive waveform design and baseline range design for maximizing the practical resolution of bistatic radar system under dynamic target scenario was devised.Simulation results show that the range and velocity resolution are enhanced according to the adaptive waveform and bistatic radar configuration.
文摘Target vdocity and acceleration are two of the most important features for identification of warheads and decoys in ballistic missile defense phased array radar systems. Velocity compensation is also the necessary step for one-dimensional range profile imaging. According to the high-vdocity characteristics of ballistic objects and the low data rate of phased array radars with multiple target tracking, a fine spectral line digital velocity tracking frame is presented and a new method is developed to extract velocity error and resolve the velocity ambiguity in the measurement loop. Simulation results demonstrate the effectiveness of the proposed technique.
基金Support by the National Natural Science Foundation of China(No.60736009 and No.60825104)
文摘When the Airborne Early Warning(AEW) radar transmits medial or high Pulse Repetitive Frequency(PRF) signal,the range ambiguity occurs.The clutter of short-range clutter has serious range dependence problem for non-Side Looking Airborne Radar(non-SLAR).As a result,the clutter plus noise covariance matrix can not be estimated correctly,and the performance of clutter suppression obtained by Space-Time Adaptive Processing(STAP) degrades greatly.The uniform linear array has not elevation degrees;therefore,the short-range clutter can not be suppressed directly.A short-range clutter suppression method is proposed.The method first estimate the elevation angles of the ambiguous short-range gate,then eliminates short-range clutter by space time interpolation and adds moving target protection in the procedure.This method can suppress the short-range clutter well.Simulation results show the validity of the method.
基金the National Natural Science Foundation of China(61471012).
文摘Radial velocity estimation used in wide-band radar systems is investigated.By analyzing the signal of cross-correlation output of adjacent echoes,it is found that the frequency and phase of the cross-correlation output are related to the target’s radial velocity.Since the precision of the phase estimation is higher than that of the frequency,a phase-based velocity estimator is proposed.However,the ambiguity problem exists in the phase estimators,and thus the estimation of the cross-correlation of adjacent echoes(CCAE)is used to calculate the ambiguity number.The root-mean-square-error(RMSE)of the proposed estimator is derived.Simulation results show that the performance of the proposed method is better than that of the frequency-based estimator.
文摘机载雷达下视工作面临严重的地海杂波,雷达平台运动造成杂波多普勒频率严重扩散,将微弱目标完全淹没。空时自适应处理(space time adaptive processing,STAP)技术通过联合多天线脉冲的接收信号,能够有效地抑制杂波,实现运动目标检测。对于非正侧视阵列高速平台雷达,杂波距离依赖和距离模糊严重制约着目标检测性能。基于多载频频控阵,通过发射一组载频不同的正交信号,在杂波回波中,获得新的发射维自由度,并根据不同模糊在发射维的差异分离各模糊区域。此外,通过进一步对分离后的近程进行杂波补偿,利用降维STAP实现杂波抑制。仿真结果验证了所提方法的有效性。
基金supported by the National Natural Science Foundation of China(Nos.61179018,61102165,61002006,61102167)Aeronautical Science Foundation of China(No.20115584006)Special Foundation Program for Mountain Tai Scholars
文摘The middle pulse repetition frequency(MPRF)and high pulse repetition frequency(HPRF)modes are widely adopted in airborne pulse Doppler(PD)radar systems,which results in the problem that the range measurement of targets is ambiguous.The existing data processing based range ambiguity resolving methods work well on the condition that the signal-to-noise ratio(SNR)is high enough.In this paper,a multiple model particle flter(MMPF)based track-beforedetect(TBD)method is proposed to address the problem of target detection and tracking with range ambiguous radar in low-SNR environment.By introducing a discrete variable that denotes whether a target is present or not and the discrete pulse interval number(PIN)as components of the target state vector,and modeling the incremental variable of the PIN as a three-state Markov chain,the proposed algorithm converts the problem of range ambiguity resolving into a hybrid state fltering problem.At last,the hybrid fltering problem is implemented by a MMPF-based TBD method in the Bayesian framework.Simulation results demonstrate that the proposed Bayesian approach can estimate target state as well as the PIN simultaneously,and succeeds in detecting and tracking weak targets with the range ambiguous radar.Simulation results also show that the performance of the proposed method is superior to that of the multiple hypothesis(MH)method in low-SNR environment.
文摘A method, called class multiple signal classification (CMUSIC), is proposed to estimate high-resolution radial velocity in each pulse train (subband, i.e. narrowband) with M pulses based on stepped frequency pulse trains (SFPTs) signal. A synthetic ultra-wideband (UWB) high-resolution range profile (HRRP) is then obtained by fast Fourier transform (FFT) processing along the subbands after compensating the range-Doppler coupling and Doppler dispersion with the estimated velocity. Compared with the other methods, CMUSIC has fine performance of velocity estimation at low signal-to-noise ratio (SNR) level. This method also has excellent performance with small Mas long as the requirement, i.e. Mis large than Q, is able to be fulfilled, where Q is the number of targets with different radial velocities. In addition, through a radial velocity resolving, the method can be well suitable for targets moving at high radial velocities, which has significant practical value with considerable progress made in the national defence technology and the advanced vehicles moving at high speed springing up. Simulation results demonstrate the feasibility and effectiveness of the method.
文摘近年来,随着智能驾驶技术的不断发展,毫米波雷达作为汽车安全控制系统的核心组件受到了广泛关注。时分复用(TDM)多输入多输出(MIMO)调频连续波(FMCW)雷达因具有低硬件成本和高角度分辨率的优势而被广泛应用于汽车雷达,但TDMMIMO在实际应用中还存在对运动目标检测易出现速度模糊和角度模糊问题,导致检测误差变大,对于自动驾驶场景存在一定的安全隐患。为解决上述TDM MIMO FMCW雷达存在检测误差高的问题,提出了在多普勒模糊下的FMCW MIMO雷达目标参数估计方法,在不增加额外硬件开销的前提下,可确保算法在低复杂度下提升监测的时效性,解决了速度模糊和相位偏移问题;利用加Kaiser窗FFT波束形成方法对目标角度进行测量,从而得到更精准的目标信息。仿真和实验结果验证了所提方法的有效性。