The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Based on the derivation of the efficient implementation structure of the frequency domain polyphase filter digital channelized receiver, a digital channelized receiver was achieved on the hardware platform with I/Q sampling, 1500Msps, 64channels. In order to ensure good performance of the system, optimization of the processor speed and processor resources was fully considered during the design process...
The phase interferometer is very important in the direction-finding and position of target. In this paper, the phase interferometer is employed to angle measurement of the stepped frequency radar target. By the way of dual-line digital phase interferometer, the contradiction between direction range and direction accuracy is solved. The effect of SNR and AOA on the accuracy of angle measurement is...
A novel algorithm of multi-burst stepped-frequency signal co-processing are proposed, from which the high resolution in both range and velocity profile of moving targets can be achieved. A fast keystone transform is presented to remove the range migration between the bursts causing by the long-term integration, which is of efficiency to implementation. A real-time signal processing system is designed...
An asynchronism problem between High-Speed DAC Chips in some multi-channel systems is analyzed. And, a method to solve this problem is proposed: Finding out the difference between clocks of each DAC, then compensating through data based on the difference in order to synchronize them. At the end, a diagram is proposed to solve the problem with this method in FPGA.
A method of parallel processing for digital channelized receiver to complex signal is proposed to solve the problem of shortage of resources in real-time signal processing. When complex signals go through poly-phase digital channelized receiver, in order to ensure there are non-blind spots and frequency aliasing, the maximum decimation factor per channel can only be half of the number of the channels...
An improved Digital Radio Frequency Memory (DRFM) system based on digital channelized receiver is stated, which employs digital channelized receiver to slow down the high speed input data flow, and uses Digital Up Converter (DUC) to generate digital intermediate frequency (IF) signal from digital baseband signal. This system can achieve broad instantaneous frequency coverage, reduce the demand for...
The principle of multiple quadrature waveform synthesis (MQWS) is introduced, which is based on the theory of quadrature modulation. Its adaptability to pulse signals is analyzed. Combined with pre-saved waveform data, this method can be used in radar signal environment simulation and it can simplify the requirement for the hardware implementation with general-purpose and flexibility characters. The...
When complex signals go through poly-phase digital channelized receiver, in order to ensure there are no blind spots and frequency aliasing, the maximum decimation factor per channel can only be half of the number of the channels. In this way, the entire receiver has to process at least twice as much data as before. This directly sets much higher requirements to the processing rate of signal processors...
Digital Radio Frequency Memory (DRFM) has been widely used for the storage of radio frequency and microwave signals. As the frequency and bandwidth are large, the implement of DRFM is limited by the speed of digital devices. A design is proposed to solve this problem based on leading technology such as poly-phase filter, Parallel-decomposition convolution and Partition of the coefficient sequence,...
This paper studies the principle of the deceptive target jamming while the radar platform is moving. It puts forward one simplified method for jamming implementation when the target has the motion styles both in uniform straight line and coordinated turn model. This method employs the IMM arithmetic for platform state estimation. It does not need to estimate the speed direction of platform, and it...
In the development of the step frequency radar, time and costs would be greatly curtailed by applying the echo simulator of step frequency waveform to verify the signal processing system. This paper analyzes the characteristics of step frequency echoes in detail and describes the implementation of the point-target echo simulator based on DDS. The experimental results of the scheme show that the equipment...
This paper introduces a method which can improve accuracy for estimating parameters of linear frequency modulation (LFM) signal. The proposed approach is based on Short Time Fourier Transform (STFT). After STFT, spike filter and detecting threshold are used to achieve high precision of parameters estimation in the time domain. What's more, moving windows and frequency compensation are done to improve...
Stepped frequency radar signal has been widely used for its high range resolution and low instantaneous bandwidth. Frequency-stepped chirp signal is a useful waveform which can decrease the frequency step number while the synthesized bandwidth remains unchanged. The spectrum synthesis method based on coherent addition is introduced to avoid the range ambiguity or “ghost” images caused by the conventional...
This work mainly discusses the image plane of the Bistatic ISAR. The image plane is modeled by two different methods separately. One is modeling the image plane according to the bistatic SAR image plane; the other is to model the plane by target rotation vector analysis. The modeling process is presented in detail. Both the models are reasonable, but are different to each other. They are then testified...
A long-term integration algorithm using the HPRF stepped frequency waveform is presented to improve the range and Doppler resolution of moving targets. A stepped frequency radar signal is applied to realize high range resolution; a long-term integration is applied to realize high Doppler resolution. Besides, with the long-term integration, the gain from coherent integration can also be improved a...
A model of DRFM system based on digital channelized receiver is introduced, it takes the advantages of channelized receiver to achieve broadband instantaneous frequency coverage, and with decimated data flow, the requirement of the memory capacity for DRFM system can be saved and make it possible to achieve real-time amplitude and frequency modulation process in radar countermeasure applications....
The range gate pull off (RGPO) results in a disaster to radar target tracking. It is assumed that the jamming (i.e., RGPO measurement, the following are the same) pulls the range gate backwards in the conventional methods. However, the RGPO for some radar, e.g., linear frequency modulation radar, can pull onwards by modulating the Doppler frequency to the returned signal. Whatpsilas more, in conventional...
An approach of implementing time-domain real-time convolution processor into multi-chip FPGA hardware platform is stated and the application of the convolution processor in radar echo signal simulator is introduced. With high speed input data flow, the algorithm of parallel-decomposition and coefficient-partitioned convolution is proposed to meet the real-time requirement. With the decomposition of...
Real time ISAR imaging of maneuvering targets is studied, when the target's maneuverability is not too serious and the Doppler variation of scatterer sub-echoes can be approximated as a first order polynomial. A FRFT (fractional Fourier transform) based ISAR range-instantaneous Doppler (RID) imaging algorithm of maneuvering targets is presented. In this algorithm, the FRFT, instead of FFT, is employed...
Wavelet denoising is proposed to be used in radar high resolution range profile (HRRP) feature extraction because the HRRP is sensitive to the target pose. It is proposed that wavelet denoising is used to process the HRRP before extracting features, and noise threshold is used as the detecting threshold of strong scattering centers. Denoised HRRP shows that the wavelet threshold denoising can eliminate...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.