263 results about "Radar waveforms" patented technology

Methods and apparatus are presented which reduce the overall cost and increase the imaging capability for medium and long range automotive radar sensing applications through the combination of a high signal-to-noise ratio and wide dynamic range radar waveform and architecture, antenna arrangement, and a low cost packaging and interconnection method. In accordance with aspects of the present invention, one way a high signal-to-noise ratio and wide dynamic range imaging radar with reduced cost can be achieved is through the combination of a pulsed stepped-frequency-continuous-wave waveform and electrically beam-switched radar architecture, utilizing a planar package containing high-frequency integrated circuits as well as integrated high-frequency waveguide coupling ports, coupled to a multi-beam waveguide-fed twist-reflector narrow beam-width antenna. Other methods and apparatus are presented.

Method and apparatus for developing radar scene and target profiles based on Compressive Sensing concept. An outgoing radar waveform is transmitted in the direction of a radar target and the radar reflectivity profile is recovered from the received radar wave sequence using a compressible or sparse representation of the radar reflectivity profile in combination with knowledge of the outgoing wave form. In an exemplary embodiment the outgoing waveform is a pseudo noise sequence or a linear FM waveform.

A method for processing received radar returns of a radiated wide-band arbitrary waveform in a wide-band radar processing system using spectral processing. The received wide-band radar returns are undersampled by using a first sampling rate to obtain an undersampled digital wide-band radar waveform. Spectral processing is performed on the power spectrum of the undersampled digital wide-band radar waveform in order to obtain a discrete ripple frequency power spectrum of the undersampled digital wide-band radar waveform. Ripple frequencies indicating radar targets are located in the discrete ripple frequency power spectrum of the undersampled digital wide-band radar waveform. A radar receiver, a digital wide-band radar processing system and a computer program product.

The invention provides an active and passive radar cooperative anti-interference method based on a waveform design, belongs to the technical field of radar anti-interference, and particularly relates to a radar waveform design technology. According to the active and passive radar cooperative anti-interference method, an active and passive radar cooperative work mode is adopted, interference is detected and identified through echo information detected by a passive radar in real time, relevant parameters of the interference are estimated, an active radar uses interference information provided by the passive radar to design the optimal transmission waveform and process the echo information, and therefore the active and passive radar cooperative anti-interference method has the advantages of being small in calculation amount and high in real-time performance, and improving anti-interference capacity of the radars in complex electromagnetic interference environments.

The invention discloses a waveform optimization method based on target cognition and transmitted power distribution, which mainly solves the problem that the current waveform optimization algorithm is not suitable for a broadband radar. The method comprises the following steps of: (1) building a waveform-optimized signal model of a cognitive radar of a broadband; (2) utilizing a single echo to estimate the power spectral density of a target; (3) calculating the transmitted power of a transmit signal being a linear frequency modulation signal to be used as a constrained initial value of the transmitted power; (4) constructing a cost function; (5) solving the cost function; (6) optimally setting the power spectral density of transmitted waveform corresponding to the transmitted power; (7) calculating the related coefficient of the estimated value and the true value of the power spectral density of the target corresponding to the optimized waveform; (8) and judging and outputting the power spectral density of the transmitted power and the transmitted waveform according to whether the related coefficient meets the requirements. According to the method, the transmitted waveform optimization and power distribution of a cognitive radar system of the broadband can be realized, and the efficiency and overall performance of the system are increased.

A radar system is disclosed, which comprises an orthogonal frequency division multiplexing (OFDM) modem and a frequency scanning antenna. In transmit, the OFDM modem modulates radar waveforms and the frequency scanning antenna radiates the OFDM modulated radio frequency (RF) energy. In receive mode, the frequency scanning antenna captures the echoes and the OFDM modem demodulates the echoes. Directionality of the frequency scanning antenna is dependent upon RF carrier frequency. In other features, the radar system further comprises a transmit/receive (T/R) module that up-converts and amplifies the OFDM modulation, and outputs the amplified signal to the frequency scanning antenna. The T/R module amplifies and down-converts a received RF echo from the frequency scanning antenna and outputs the down-converted echo to the OFDM modem. A plurality of scanning angles are measured simultaneously.

A method and apparatus for selecting frequency modulated continuous wave waveform parameters for multiple radar coexistence by a user equipment is described. The user equipment may transmit a radar waveform consisting of a number of chirps, with each chirp having a same duration. The user equipment may vary waveform parameters of the radar waveform for at least a subset of the number of chirp, where the waveform parameters may be chosen from a codebook comprising at least one codeword of parameters. Reflected radar waveforms are received and processed where the processing includes applying a fast time discrete Fourier transform to reflected radar waveforms to produce a one dimension peak in a time delay dimension for each reflected waveform; and applying a slow time discrete Fourier transform to the reflected radar waveforms, where peaks for the reflected waveforms are added.

The invention relates to a UWB radar signal simulator based on FPGA, comprising a PC104 interface module, an RAM module, an FPGA module and a high-speed DAC module; the PC104 interface module completes data transmission with a host with PC104 mode by a PCI protocol; the RAM module adopts six ZBT-SRAMs with the bit width of 32 as data cache; the FPGA module adopts Virtex-4 series of product XC4VLX40 offered by Xilinx company and comprises a PCI interface control module, a RAM control module, a high-speed DAC control module and a radar waveform control module; the high-speed DAC control module selects AD9736 of ADI company; the interconnection of all the modules is realized by control modules in the FPGA module, the PC104 interface control module completes butting joint of the FPGA module and the PC104 interface module; data generated by controlling a host computer is transmitted to the inner part of the FPGA module from the PC 104 interface module; the RAM control module completes butting joint of the FPGA module and the RAM module so as to realize the transmission of data between the FPGA and the ZBT-SRAM; and the high-speed DAC control module completes butting joint of the FPGA module and the high-speed DAC module and controls the high-speed DAC module to generate various radar waveforms.

The invention relates to a multi-frequency multi-base high-frequency ground wave radar system and an operating method thereof. The multi-frequency multi-base high-frequency ground wave radar system comprises an analog extension, a digital extension, an ultra-high-stability time frequency standard device, a power amplifier, a transmitting antenna, a receiving antenna and a GPS (global position system) antenna. The analog extension comprises a frequency synthesizer, an analog amplification filtering component, an analog frequency multiplier and a multi-channel analog receiving front end, and the digital extension comprises a multi-channel data acquisition and processing board card, a synchronization control board card and an industrial control computer. The frequency synthesizer adopts a digital up-conversion scheme; the analog receiving front end adopts a multi-stage broadband program-controlled tracking and filtering scheme with no need for frequency mixing; data acquisition adopts a radio-frequency direct sampling and digital down-conversion scheme; and the time frequency standard is provided by a GPS tame low-phase-noise and ultra-high-stability crystal oscillator. The multi-frequency multi-base high-frequency ground wave radar system has the following advantages that the all-digital transmission and reception technology is adopted, and the system has good universality and scalability; and the radar waveform and time sequence are flexible and controllable, and the time-sharing, multi-frequency and single-base or multi-base detection can be realized.

A method and apparatus for cognitive non-linear radar processing comprising identifying one or more frequency bands of interest, passively scanning, using a non-linear radar (NR), the one or more frequency bands of interest to determine whether interference signals are occupying the one or more bands, transmitting radar waveforms and receiving radar waveform responses at one or more frequency bands determined to be free of interference, determining a likelihood of a target being present or not based on whether the received waveform responses match stored waveform responses for non-linear targets, and modifying waveform parameters of the transmitted radar waveform when the received waveform responses match the stored waveform responses, so as to transmit a modified radar waveform.

The invention discloses a multi-input multi-output radar waveform design and processing method, specifically comprising the following steps: setting waveform parameters according to the resolution power of radar and the zero side lobe band request, and forming a multi-phase sequence matrix; forming the multi-phase encoding sequences of various transmission waveforms by using various lines orderly connected with each other in series in the multi-phase sequence matrix; using the multi-phase encoding sequences connected in series to respectively perform encoding modulation for the base pulse to generate the transmission signals of various transmission array elements of the transmission array; transmitting the generated transmission signals by various transmission array elements; receiving the echo signals of the transmission signals reflected by the target object through the receiving array elements of the receiving array; performing base band conversion and A/D conversion for the echo signals; regarding the transmission signal as the reference signal, and performing pulse compression processing for the echo sequence of various receiving array elements from the frequency domain; and using the scheduled range gate to intercept the pulse pressure output echo sequence according to the stated time interval to limit the interference of the side lobe. The application of the waveform processing method can fully eliminate the interference of the correlative side lobes with different transmission waves in the multi-input multi-output radar pulse compression output signal sequence in the range of the stated distance so that the precise separation for the target scattering information in different observation channels can be realized so as to improve the precision of the following radar signal and data processing.

The invention discloses a laser altimeter vertical control point generating method in combination with a stereopair. The method comprises the steps that dense elevation point cloud data is obtained through a stereo camera; then point cloud data within a footprint is classified according to elevations, and the surface feature classification number at different elevations within a light spot is obtained; finally, large-spot laser radar waveform decomposition is guided through the classification number, and a generalized vertical control point is obtained. The aim of cooperative mapping of the stereo camera and satellite-borne laser radar is achieved, the result of three-dimensional positioning of a laser altimeter is combined with the mapping result of the stereo camera, and automatic extraction of the generalized vertical control point is achieved.

The invention relates to a poly-phase code radar signal waveform automatic identification method based on continuous wave Doppler (CWD) feature and belongs to the technical field of information countermeasures. According to the poly-phase code radar signal waveform automatic identification method based on CWD feature, a discrete sampling type Choi-Williams conversion is used as a basic tool, a CWD image of poly-phase code pulse compression radar signal is used as a feature extraction object, a Pseudo-Zernike moment of the CWD image, a target number of an image, a time position of a peak power in a CWD and a poly-phase code waveform symmetrical property are taken as features to identify a poly-phase code pulse compression radar waveform, and a neural network which is composed of 10 perceptrons and stops in advance of overall average is set up for automatic waveform identification. The poly-phase code radar signal waveform automatic identification method based on CWD feature has the advantages that the identification precision of the poly-phase code radar signal waveform is improved, the requirement of a signal to noise ratio is further decreased, and a new way can be developed for the design of radar signal identification and sorting by popularized and used in a poly-phase code continuous wave radar signal.

The present invention discloses a method for performing adaptive variable waveform switching to track a target. The invention aims to provide a target tracking method which is short in echo receiving period, high in scanning time resource utilization rate and is capable of increasing radar detection distances. The realization process of the method of the invention includes the following steps that: on the basis of a distance detection range R required by a radar and an allowable transmitter duty ratio D, the detection range R required by the radar is divided into N segments, and adjacent distance segments are overlapped; the allowable maximum scanning time of each segment is calculated according to the maximum distance, beam width, wavelength, target speed and target acceleration of each distance segment; a pulse width and a radar pulse repetition frequency corresponding to each segment are calculated; the allowable maximum scanning time of each segment is calculated; and phase-coherent accumulation pulse counts corresponding to each distance segment is determined according to the maximum scanning time, and radar waveform parameters according to which corresponding pulse widths and radar pulse repetition frequencies change correspondingly when required distance coverage changes with the target during a period when the target flies from the distant to the near or from the near to the distant are also determined.

The invention discloses a laser radar waveform time discriminating method and an online distance measuring system, wherein online waveform processing of a laser radar signal and real-time distance measuring are realized. The method comprises the steps of acquiring a pulse signal which is output from a detecting and receiving unit by a laser radar high-speed acquiring and processing unit, determining a target function and a fitting parameter vector by a programmable processor of the high-speed acquiring and processing unit through a waveform characteristic, determining a signal effective rangeand realizing waveform cutting, performing online calculation of an initial fitting target function based on the cut waveform, performing real-time calculation of an error between the initial fittingtarget function and the acquired signal for determining a residual error vector, performing parallel calculation on a residual error vector partial derivative and determining a Jacobian matrix; determining an optimal condition of the residual error vector based on the Jacobian matrix, and performing online calculation of a final fitting target function; determining a pulse time based on an onlinefitting parameter vector, calculating a target distance, combining distance measuring data and waveform data, and uploading the combined data to an upper computer for displaying and storage. The laserradar waveform time discriminating method and the online distance measuring system can realize online waveform parameter vector extraction, distance resolving and point cloud generation.