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Aiming at the problem of common-frequency interference among gun-pointing radars, frequency agility technique was introduced. The reason why existing technique of frequency agility can’t investigate and identify common-frequency interference effectively was analyzed. A new frequency agility technique based on auxiliary channel and full-time reconnaissance and receiving is presented. Auxiliary channel investigates and identifies environmental signals full-time not intermittent, then uses microwave cancellation technique to eliminate local radar’s emission pulses. As a result, when auxiliary channel amplitude is greater than the main channel, it must be common-frequency interference. The above measures guarantee the accurate identification of common-frequency interference.

In this paper, the basis function of TDCS system (Transform Domain Communication System) is used to design cognitive radar transmitter waveform. Based on the noise environment, the waveform can be adjusted adaptively. Then after clipping to reduce the PAPR (Peak to Average Power Ratio) of radar echo signal, the obtained signal is used as the next launch of the radar signal. The cognitive radar transmitter requires a nonlinear waveform to improve the efficiency of radar transmitter power amplifier, so reducing the PAPR of signal is essential. This paper presents the gray complementary sequence is applied to TDCS communication systems, and then it needs to reduce PAPR of signals by clipping. Proven, PAPR of the transmitted signal is maintained at about 3.25dB, and the signal has a low probability of intercept, high anti-interference ability and distant target detection range.

Based on the chirp signal radar using DDS technology, the waveform of the wideband chirp signal source is analyzed. By analyzing the system error model, the method that selecting the chirp steps in accordance with the digits of DDS phase truncation is proposed. It reduces the system errors caused by the phase truncation.

This paper introduces the basic principle of phase code pulse compression technology, the characteristics of phase coded pulse compression system, and the technical approach of radar to implement phase code pulse compression.

This paper has introduced a kind of method which can simulate the echo signal of radar receiver by the use of the Digital Radio Frequency Memory (DRFM) and Programable Logic Device (PLD).With the realization of actual circuit,the echo simulator can produce intermediate frequency and video signals.Therefore,with the help of the echo simulator, we can raise the detection ability of radar receiver system considerably. The structure of the simulator is simple but its function is great.The echo simulator can simulate intermediate frequency signals of radar receiver system for the first time.So the simulator can locate where isn’t work well of the radar receive system.

With the development of science and technology ,microwave measuring instrument become more important in the radar equipment maintenance support task.This paper expounds the principles of microwave measuring instrument work and test, describes the application of microwave measuring instrument in the maintenance detection of radar antenna feed system、radar antenna pattern test、power amplifier parameters measurement、the local oscillator test and receiving systems component test. Scientific applications of microwave measuring instrument is the important guarantee to ensure the radar equipment operate effectively.

This paper study continuous wave radar data processing algorithm for low altitude detection, it is applied to continuous wave low altitude search radar data terminal, it can realize real-time correlation and track processing for the data of target echo and false alarm false alarm filtering, to get the real targets of track parameters. Finally, through the realization of FPGA, the experimental results achieve the precision of the system.

The dynamic target echo intermediate-frequency signal source can be used to detecting and repairing receiving system, signal processing system, display system of conventional radar. The output frequency which conducted by the signal source can be adjusted. The range of output signal frequency basically covers different types of radar, which has important practical application value on the maintenance of radar. The dynamic target echo intermediate-frequency signal source is make up of source processing unit, intermediate-frequency unit, monitoring unit, the time reference source, input and output driver board and power supply pulse generation. Pulse processing unit in the signal source is in the core status.

Recently, the concept of software radar has been proposed. The wide application of the digital technology has become a trend. With the development of modern radar system, the system requires higher and higher performance to the radar receiver. The technology of digital receiver has become an effective implementation method for high-accuracy and wide-band radar receiving systems. However, most of the digital receiver can only receive one wide-band signal with one center frequency. A multi-frequency digital receiver which can receive several center frequencies of signal simultaneously [1] is discussed in this paper. We also describe the theory and the design about digital receiver, introduce digital downconversion (DDC), FIR and decimation, digital beam forming and channel calibration. Based on the research, a realization of multi-frequency digital receiver based on FPGA is put forward. The analysis and simulation is made and the result shows the design of great performance.

Analysis on the operation principle of digital radio frequency memory range (DRFM) with range gate pull off/in (RGPO/RGPI), a model of jamming signal is found in this paper. The use of stretch in the process of radar seeker receive signal is considered, so that the actual target echoes and jamming echoes will be moved into different frequencies. Then a low pass filter can be utilized to cancel the jamming signal and the actual target echo can be rebuilt through inverse stretch dealing. The simulation results show that this method can effectively suppress jamming signal.

A new type of tachometer carbon brush wear detection technology is proposed based on data acquisition and signal processing technology, the key of which is that the tachometer carbon brush output information is acquired and processed, moreover, the real time conditions of the carbon brush wear are detected and analyzed based on the time domain Eigen value analysis method. During the data processing process, the results of the dimensional parameter processing method are compared with the results of the dimensionless parameter processing method at the same time. Then, we find that the detecting precision is greatly promoted and measurement probability is guaranteed by reasonable threshold selection. Experimental results indicate that the technology proposed here has high stability, high reliability, and high detecting probability, which has great practical value and deserves being extended widely.

Smart jamming based on convolution modulation brings a great threat to active radar seeker. In order to counter the jamming, a method of orthogonal projection is designed. Firstly, both the mathematic models of linear frequency modulation (LFM) signal and convolution modulation smart jamming are made. Secondly, the anti-interference principle of orthogonal projection is analyzed, on the basis of which a reasonable filter is designed. Thirdly, simulations of signals respectively convolved with noise, triangle pulse sequence and rectangular pulse sequence are made, which verifies its good interference effects. The conclusion is that the method can effectively suppress the convolution modulation smart jamming.

In view of the traditional zero-angle memory device with low precision and to reduce errors caused by manual readout, this paper using electro-magnetic technology, designed a new zero-angle memory device based on proximity switch. Experimental results show that the device not only improves the repeatability and reduces the error, but also realize automatic demarcation.

High stability and constant-temperature crystal oscillator as time standard, microcontroller as control core, the countdown frequency measuring electric circuit, rapidly and timely surveying the transmitting frequency during the constant radar transmitted pulse, is a digital frequency measurement module. This module is an important constituent part in digital automatic radar frequency control system, having been successfully applied in a self-adaption frequency control system of meter wave warning radar.

Multiple-input multiple-output (MIMO) radar with frequency diversity (f-MIMO) is applied to HF radar. An array processing model of f-MIMO HF radar is developed. To eliminate the grating lobe of f-MIMO radar beamforming, two approaches are proposed. One is to apply particle swarm optimization (PSO) algorithm to select the optimal carrier frequency combination. Another is to extract array elements from the virtual receive array to get the optimal sparse array structure, and the simplified physical receive array structure is proposed. Simulation results demonstrate the effectiveness of the method proposed.

Based on fuzzy logic control adaptive bandwidth PLL design is presented for the problem of tracking poor stability and low accuracy when a certain type of radar tracking dynamic spacecraft. This method is mainly through fuzzy logic controller, adaptive level is determined by control rule of input respectively, and the outputs of rules are weighted combined to control the coefficient of loop filter, thus adjusting automatically the loop bandwidth, and enhancing the tracking stability of radar equipment and improving ranging accuracy. The simulation results show that the fuzzy logic control adaptive bandwidth PLL has higher tracking stability and accuracy.

In recent years radar life detector is the rapid development product of information technology and Biomedical Engineering, and its core is to not contact with the human body, but to realize the detection of the parameters of human life which has a breakthrough, and to explore with full range. This paper first analyzes the principle of radar life detection system and the implementation scheme of each module technology. Based on this, DSP digital signal processing method is used to design the structure system of radar life detector. Further based on the DSP signal processing principle, PD distance tracking is used to approximately simulate the time domain of human heartbeat signal. The results show that the tracking effect that is under this structure is remarkable, which has provided technical support for the practice of the area to a certain extent.

This paper discusses photovoltaic radar target simulator using NN, which provides a virtual simulation test environment for photovoltaic radar. A description of the controller architecture and associated stability analysis is given, followed by a more in-depth look at its application to a tiltrotor aircraft. Finally, it is proved that the control process of the photovoltaic simulator has superior performance and expected effect.

A novel OFDM radar processing algorithm using pilot signal is proposed in this paper. Based on the prior knowledge of the pilot signal in OFDM symbol in communication system, the receiver can estimate the transmitter's range, velocity by the processing of the received modulation domain signal. In addition, we test the approach by the OFDM frame signal of the famous IEEE Std 802.11p, the results show it can work robustly and is very suitable for the vehicular application.

First analyzing electromagnetic compatibility system of the wired circuit, and then electromagnetic shielding, PCB board electromagnetic compatibility and filtering are used to develop an anti-broadband electromagnetic interference wired phone. It can resolve practical problems of SLT dialing error in strong electromagnetic interference, voice unclear and intermittent communication. After 30 days test, experiment shows that in 50m radiating field of high-power VHF radar or shortwave radio, speech intelligibility of phone designed was higher than that of general phone and had no whistling or ringing.

In order to develop an anti-broadband electromagnetic interference wired phone, speech enhancement, electromagnetic shielding, PCB board electromagnetic compatibility and filtering are the usual measures. Realization of speech enhancement can resolve practical problems of SLT dialing error in strong electromagnetic interference, voice unclear and intermittent communication. The experiment shows that in 50m radiating field of high-power VHF radar or shortwave radio, speech intelligibility of phone designed was higher than that of general phone and had no whistling or ringing.

To solve the problem of sliding-type scattering center and the problem of angle limitation of single radar, a kind of method for extracting three-dimensional micro-motion characteristics of ballistic target based on netted radars was proposed. Firstly, A new feature extraction method based on half period delay multiplication was introduced which establishes the relationship of sliding-type scattering center and ideal scattering center, then making use of the expand hough transformation, the parameters of echo signals were extracted. At last, the three-dimensional micro-motion features and the structure features were obtained by solving nonlinear multivariable equation systems which were established by the multi-view of netted radar. Simulation validated the method can get both the high estimating precision and the three-dimensional micro-motion parameters.

This research aimed to separate the signals of respiration and heartbeat effectively from the biological radar echo signals of vital signs detecting platform. Therefore the characteristics parameters of the respiration and heartbeat could be extracted to provide the basis for clinical diagnosis and disease prevention. This paper put forward a separation algorithm of heartbeat and respiration based on LMS adaptive harmonic cancellation, the combined harmonics of the breathing signal was regarded as a reference input signal of the adaptive filter to improve the algorithm. Related experiments were designed to conduct filter processing. Results show that the algorithm proposed proved to be more effective in the signals separation of respiration and heartbeat.

Modern radar systems should transmit different waveforms according to different environment. Waveform design is an important problem in radar system design. In this paper, we compare two waveform design methods based on MI and SINR with the signal model of a Gaussian target ensemble in ground clutter. The simulation results show that for the different tasks of radar, the energy allocation modes are different. Finally, the whole paper is summarized.

CS is a very new method that is being evaluated for many applications, in which signals are sparse in some basis/dictionary, e.g. the radar range profile. In this article, we have formulated the range processing with CS and introduced fair comparisons between matched filter and CS with chirps and OFDM signals. Two relevant features have been inspected: waveform bandwidth and measurement matrix.

Two realization methods of multi-frequency and multi-polarization technique in radar are proposed. One is design of multi-carrier-multi-polarization radar signal, and the other is design of multi-band-multi-polarization filter bank. The consistence of spectrum and polarization properties between them is derived in principle, and simulation experiments are carried out to verify the conclusions at last.

The Vehicle Active Anti-collision Warning system often adopts the millimeter-wave radar with linear frequency-modulated continuous (FMCW) system as its signal acquisition and processing device. Affected by the road environment and their own devices, intermediate frequency (IF) signal inevitably exist in a variety of interference and noise. This paper proposed an iterative Kalman filter algorithm to remove the noise from IF signal. And used of MATLAB to do the simulation analysis. The analysis results show that the improved algorithm enhances the precision of de-noising effectively and meet the requirements of real-time and accuracy.

In the modern wars under the condition of informationalization, radar signals are generally characterized by repetitive patterns in time, so it is one important task of Radar Warning Receiver (RWR) to estimate the Pulse Repetition Interval (PRI) of all radar signals by intercepting and identifying the mixed radar signals. Because each transmitted radar signal are arbitrary in general. From the view of statistic, the transmitted radar pulse train from different radars is mutual independent. So the constituted model of RWR and radar transmitters accord with blind source separation which can separate mixed signals into pure signals. A deinterleaving method using blind source separation for estimating the PRI of each radar signals is proposed. The implementation architecture of the proposed method is given. Finally, computer simulations show the proposed method can gain good performance for the estimation of PRI of radar signals.

Introduced the internal function of UC3844, and analyzed the working important point of switching power supply. Planning and design of the radar level measurement instrument of multiple output power supply circuit.

When multiple targets run through radar at the same time, the current traffic speed radars have more speed error. This paper presents an improved measuring method, provides a solution to improve time-frequency resolution. We can improve the speed resolution when adopting the algorithm proposed in the paper.

Aiming at many fault characteristic parameters of modern radar and the problem that general diagnosis method is difficult to locate fault accurately. The dynamic mathematical model of radar equipment fault diagnosis system is built. The uncertainty theoretic analysis of fault diagnosis result is studied from two aspects, data processing channel and fault model. This paper combines sensor data validation with detection fusion technology, and then puts forward the fault diagnosis technology based on sensor data validation and detection fusion. The structure of the diagnostic system model is given. Case analysis proves that the proposed model and method has a significant role in improving detection performance, reducing the Bayes risk and improve fault diagnosis rate.

Radar sensors like ultra-wideband Doppler radar sensors may be utilized as a vibration sensing device in a restricted area for railroad monitoring. As long as something or someone enters the restricted area, the alert signals will be sent to the control center or train driver to stop the moving train and prevent accidents. Combining with visual monitor system, the radar sensors may compensate for the insufficient information under poor lighting, fogging, or raining environment. The simulations and experimental results supported its feasibility in a railroad system. The feasibility of further radar application is also discussed.

Based on GaN HEMT the monolithic microwave power amplifier (MMIC) with great advantages of high operating voltage, high output power, wide frequency bandwidth and small features loss has been widely used in phased-array radar, aerospace, missile interception system. However, MMIC test has many disadvantages, such as, including many microwave instruments, test process is complex, manual operate lots of instruments, and write down test data, result in slowed down test process. In the paper, it introduces a new system by ourselves. This can simplify the MMIC test process, and free ourselves from heavy test task, and focus the performance of circuit. It realizes the automatic test and proves it using a based on GaN HEMT 2×4 MMIC circuit.

Ultra-Wide Band (UWB) technology is making progressing rapidly, and many meaningful applications based on this technology are under studying. For instance, UWB Radar for Human Life Detection is a promising usage, which is considered as an effective machine to rescue the earthquakes’ victims, detection weapon in anti-terrorism wars, and medical device to detect patients’ life information. In this paper, a non-invasive UWB Life-Detection Radar developed in simple structure is described, and the key mechanism of this system is given, the method of processing the radar echo signal is discussed, finally, the results of the life-detection experiments based on this radar are introduced.

For frequency modulate continuous wave radar, it is necessary and difficult to search the pairs of beat frequencies in an up-chirp mode and a down-chirp mode t o measure range and velocity of multiple targets. However, the inherent problem of FMCW radar is multiple targets detection. False targets can appearance because of mistaking the combination of these beat frequencies. A novel waveform named double-slope symmetrical saw-tooth wave is proposed and its corresponding algorithm is also introduced to resolve the problem of multiple targets detection for automotive anti-collision radar. Computer simulation results and theoretical analysis prove that the method is effective and practical for multiple targets detection in intelligence transportation system.

Due to the rapid development of manufacturing technology, high-speed high-resolution data acquisition system has been widely applied in plenty of engineering fields, such as radar, environmental surveillance, mass spectrometry, etc. In order to satisfy the increasing requirement, we present the design of a high-speed data acquisition system, which is mainly composed of high-speed time-interleaved analog-to-digital converter, high data throughput interface based on 10 gigabit Ethernet. The detailed design and realization of each module are presented. Finally we test and analysis the performance of the ion signal acquisition system, and the results show that the system performs fine speed, high precision and stability.

An implementation framework of stepped-frequency LFM (SF-LFM) radar echoes simulator is presented in the paper based on the decomposition and calculation of SF-LFM radar echoes of a moving target. The proposed method can be implemented conveniently with direct digital synthesis (DDS) logic resource. The feasibility of this resolution is verified with computer and semi-physical simulations experiments.

Along with the rapid development of computer technology, high speed data acquisition and storage system has been widely applied in plenty of engineering fields, such as radar, aerospace industry, communication, etc. In order to satisfy the increasing requirement, we present the design structure of a novel integrated instrument for ultra-high speed data acquisition and storage, which is composed of ultra-high speed data acquisition, high speed data transmission and solid storage three main sub-systems. The detailed design and realization of the sub-systems are presented. We test and analysis the performance of the integrated instrument and the actual results show that the instrument performs stably and provides excellent speed and precision.

A Wideband Signal Generation System for radar and Electronic Warfare is presented. This system uses two DACs each can work at 1Gsps with 14-bit resolution and generate 500MHz bandwidth signal. The DDWS (Direct digital wave synthesis) method is used for signal generation and the data transfer and controlling is based on FPGA. The data for signal generation is stored in ZBT-SRAM and the system can communicate with the controller module through PC104+ interface. The system structure, implementation and test results are described in detail.

An active cancellation stealth system was designed based on the phased array techni- que, digital radio frequency memory (DRFM) and field programmable gate array (FPGA). Using the off-line calculation method, which establish goals of omnidirectional radar cross- section (RCS) database, clutter and noise database in advance. Signal processing and control module analyzes the measured radar signal parameter , then find the corresponding target echo data in the RCS database, and real-time adjustment of coherent echo amplitude and phase. Make target scattering field and artificial introduced into radiation field coherent cancellation in radar direction, so that the radar receiver is always in nulls synthesis pattern. Through the combination of software and hardware of the method in engineering realization of active cancellation stealth.

A scheme for simulation of DBF used in radar seeker by Simulink is proposed in this paper. Considering the feature of digital devices, an optimized modular simulation model is built up. Experiments show that the model parameters are flexible and results are reliable, which can be used in hardware design for reference.

Owing to the incompleteness and asynchronicity of the observation data, it is hard for the asynchronous netted radar to track its target effectively under intense blanket jamming. This paper presents a kind of data fusion algorithm for the asynchronous sensors based on optimal linearization approach, providing a solution to the problem of target tracking of radar networks under blanket jamming. First, the optimal linearization processing technique of the observation equation is derived. Then, based on this, the state vector of the target is initially estimated in batch mode. Finally, the filtering is processed in sequence. The simulation results show that the data fusion algorithm presented in the paper can track the target in high accuracy.

This paper presents a new algorithm for the deinterleaving of radar signals, using the direction of arrival (DOA), carrier frequency (RF), and time of arrival (TOA). The algorithm is mainly applied to pulse repetition interval (PRI) signals. This algorithm consists of two steps: In the first step, a PRI transformation is used to the received pulses after pre-deinterleaved of frequency and DOA. In this step, radar signals having the same frequency and DOA are identified as the same class. In the second step, the number of existing emitters and their PRIs is determined by using TOA information. The algorithm for deinterleaving uses the information obtained from the previous analysis to reduce the PRI errors. The simulation results show that the algorithm is successful in high pulse density environments and for the complex signal types.

This thesis focuses on the influence of VCO modulation voltage on LFMCW radar beat signal. Firstly, analysised the serious effect to beat signal spectrum caused by flyback voltage. Because of the false frequency component would be produced by voltage flyback. So that the radar measurement system can't be measured the correct distance information from the inaccurate peak detection. Thus, both digital signal processing and hardware produce synchronized signal are used to solve the bad influence by voltage flyback brought to LFMCW radar. Finally, compared the processing results with the null group, results shown that modulation voltage flyback would brought great difficulties on signal spectrum analysis, thus, the disturbance signal of flyback section should be processed during practice.

To reduce the accident, a radar speed measuring and monitoring system based on DSP chip-TMS320F2812 is designed in this paper. Continuous wave radar is used to receive echoes which are reflected from moving vehicles and frequency spectrum is analyzed with FFT. And then, velocity is calculated with the Doppler effect formula. Finally, the velocity is uploaded to the monitoring center by RS-232 UART. An experimental platform is produced and do the experiment by this method, simulation and experimental data show that it is an effective way to improve the speed-measuring accuracy and reduce accident rates.

In this paper, a novel netted radar system is designed to reduce the influence of mutual interference between signals. The emission signals of all stations are assigned the orthogonal PN codes. Because of the good autocorrelation and cross-correlation properties, mutual interference becomes weaker and signals from different stations could be separated by the preassigned PN codes. At the same time, the spectrum of the emission signal is spreaded, the peak-to-mean envelope power ratio (PMEPR) and the intercepted probability of the signals descend therefore. Simulation results show the good performance of the proposed approach.

In this paper, a 34 to 36 GHz vector modulator for using in low cost and high performance RPC (Reflected Power Canceller) is presented. The key circuit consists of two push-pull (bi-phase) attenuators arranged in phase quadrature and a 3dB quadrature coupler (branch line couplers but not Lange couplers which is different from traditional circuits in Ka band) and a Wilkinson combiner, and then transition from micro-strip to waveguide using antipodal finline. To fully exploit this circuit’s capacity to generate accurate constellations at millimeter-wave frequencies, a generalized theoretical analysis of the (push-pull) vector modulator is presented. Based on the theoretical model and the measured results, the I-Q (push-pull) vector modulator promises to be a vital component for the realization of reflected power canceller in LFMCW (Linear Frequency Modulated Continuous Wave) radar.

A pseudo-random phase-coded quasi-CW radar signal processor is designed，and implemented based on a parallel signal processing platform. Distance sidelobe and “echo eclipse” are two problems inherent to the phase-coded quasi-CW radar. In this paper, “Code agility” method is used to suppress the distance sidelobe, which has good performance even when the radar echo is badly eclipsed. Software of the radar signal processor is characterized by pipelined processing, and the DSP program is based on real-time operation system. Results of the field experiment verify the correctness of our design.