197 results about "Digital array" patented technology

The invention discloses a system and a method for forming digital wave beams of a two-dimensional digital array radar, which mainly solves the problems of limited data transmission and arithmetic amount, small scale of the system and inflexible control of the wave beams in the prior art. The system of the invention comprises a two-dimensional rectangular digital array antenna of M*N array elements, a digital signal processing (DSP) device, a field programmable gate array (FPGA) device and peripheral accessory devices. The method for forming the digital wave beams comprises the following steps: the FPGA device receives the frequency, azimuth angle and pitch angle information of received wave beams transmitted by the two-dimensional digital array; and the DSP calculates the sum, the difference, and the row and column wave beam weights of the two-dimensional digital array according to the information received by the FPGA, and the weights are transmitted to the FPGA device; and the FPGA device utilizes the weights and a target echo signal transmitted by optical fibers to form the sum, the difference, and the row and column wave beams of the two-dimensional digital array in the FPGA device. The invention has the advantages of large data transmission quantity and scale of the system, mass amount of the wave beams, flexible scanning of the wave beams and strong instantaneity, and is suitable for forming the digital wave beams of a large-scale two-dimensional array radar.

The invention discloses a super-resolution height measuring method based on topographic matching for a digital array meter wave radar, which is mainly used for solving the problem of high height measuring error of a fluctuating position in the prior art. The method comprises the following implementation steps of: performing clutter cancellation and interference cancellation processing on a targetsignal received by the radar to obtain a cancelled target signal; roughly measuring a target elevation angle by using a beam forming method; determining a maximum likelihood search range according tothe roughly-measured elevation angle and searching in the search range; computing a ground reflection point coordinate corresponding to each array element and a direct wave path and a reflection wavepath of each target relative to each array element according to a search elevation angle; computing a corresponding direct steering vector and a multipath steering vector by using the direct wave path and the reflection wave path; constructing a synthetic steering vector and computing a projection matrix of the synthetic steering vector; and performing maximum likelihood estimation to obtain a target accurate elevation angle. In the method, an altitude parameter of a radar position and the synthetic steering vector are introduced into super-resolution height measurement, so that the measuringaccuracy is increased; and the method can be applied to target tracking.

The invention discloses a wideband digital wave beam forming method based on an all-pass type variable fractional delay filter. The problem that a needed filter in the prior art is large in order number and high in complexity is solved. The method comprises the steps that (1) according to radar system parameters, sampling rate fs and sampling time ts are determined; (2) according to the radar array geometric structure and the sampling time ts, a propagation time delay tau of each array element relative to a reference array element is calculated; (3) according to the sampling rate fs, an AD chip is selected to digitize analog signals received by the array elements; (4) according to the propagation time delay tau and the digitized received analog signals, the all-pass type variable fractional delay filter is designed; (5) the digitized received signals are filtered; (6) phase delay of the filtered signals is compensated for; (7) a window function is selected to conduct weighted summation on the filtered compensated signals to obtain a wave beam forming result. The wideband digital wave beam forming method can achieve wideband digital beam forming, saves hardware resources, improves instantaneity and can be used for wideband digital array radar.

The invention relates to an LC quadrature VCO (voltage controlled oscillator) which can reduce the intermittent noise, belonging to the technical field of integrated circuit, . The invention is characterized in that two negative resistance oscillators are connected together with a quadrature coupler to output quadrature signals; the reduced phase noise is implemented by using a more linear narrow-band turning variable capacitor structure, multiband switching digital array with a lower parasitic capacitance and an intermittent noise eliminating circuit reducing the intermittent noise getting into the LC oscillator when inputting voltage crossing the zero point.

The invention discloses an automatic digital array reception channel performance test system based on cPCI. The system comprises a host computer and a data acquisition board card based on a cPCI interface, wherein the data acquisition board card comprises a cPCI interface unit, a processing control unit, a buffering unit and a photoelectric conversion unit, the photoelectric conversion unit is connected with the processing control unit, the data is acquired by the processing control unit through the photoelectric conversion unit and is stored in the buffering unit, the processing control unit realizes communication with the host computer through the cPCI interface unit, work parameters are configured by the processing control unit on the basis of a control instruction of the host computer, the buffering data is transmitted to the host computer, the host computer is used for emitting a control instruction to the data acquisition board card for performing data acquisition, the reception data is drafted into frequency domain and/or a time domain waveforms which are then outputted, test index operation is carried out on the basis of the reception data, and output is carried out. Through the system, performance test on each reception part of a digital array radar device is carried out, rapid, high-efficiency and accurate performance evaluation can be realized, and fault positioning can be further realized.

The invention relates to an intensity calibrating method of all-digital array phased-array weather radar. The intensity calibrating method includes the steps that a radar monitoring terminal controls a correction extension set to send out simulation target signals, and a product terminal calculates an actual pulse pressure gain Gp; the radar monitoring terminal controls the correction extension set to send out a plurality of linear frequency modulation simulation target signals with fixed and sequentially and gradually attenuated echo power values, after the linear frequency modulation simulation target signals are processed by a signal processor, echo signal intensity values and spectrum processing signal intensity values are produced and sent to the product terminal through a network so as to be recorded into an intensity calibrating and testing record list, and an intensity curve yDVIP and a spectrum processing intensity curve yFFT are produced after fitting is conducted on the intensity calibrating and testing record list through the least square method; the product terminal inversely calculates echo power Pr when the radar normally works; the value of the obtained echo power Pr is substituted into an improved radar meteorological equation to obtain the value of a radar reflectivity factor dBZ. By means of the method, the special implementation steps and special testing processes of all-digital array weather radar intensity calibrating are established, and the method is fit for engineering practice and is simple, practical and high in calibrating accuracy.

The invention provides a far field test system and test method for a digital array secondary radar antenna pattern. The test system comprises a computer, a data processing module, a local oscillator module, a tester, a horn antenna, a digital T/R assembly, an array antenna and a turntable; a digital array secondary radar antenna emission pattern test module determines all frequency points and digital array secondary radar antenna emission patterns at different scanning angles; a digital array secondary radar antenna receiving pattern test module determines all frequency points and the digital array secondary radar antenna receiving patterns at different scanning angles. The far field test system for the digital array secondary radar antenna pattern can be unfolded under any environment meeting the far field test distance conditions, can automatically finish all tests of the needed far field patterns without manual intervention, and is easy to implement in engineering.

The invention relates to a digital array radar amplitude-phase monitoring and calibration method based on an optical fiber delay system. The method mainly includes the steps that a radar array front array element and an array front monitoring coupled array element are utilized to collect amplitude-phase data of all uplink channels and all downlink channels of the radar array front array element in a mutual coupling mode, amplitude-phase monitoring of all the uplinks and the downlinks of a radar array front is finished, when amplitude-phase correction and calibration need to be conducted on the array front, the difference value between the amplitude-phase data and factory data is acquired through amplitude-phase monitoring, and then amplitude-phase calibration of the uplinks and the downlinks of the array front is finished after the difference value is corrected. According to the method, the optical fiber delay system is introduced to separate transmitting time from receiving time, within a transmitting monitoring operation time sequence, the monitored channels work in a deep blanking state, optical fiber amplitude-phase drifting self-calibration is finished, and accuracy of monitored data is guaranteed. The method has the advantages of being good in real-time performance, convenient and quick to operate, and good in cost performance. The presentation and engineering realization of the method have high practical application value in the field of digital array radar monitoring and calibration.

The invention discloses an ultra-low side lobe adaptive digital beam forming (ADBF) method for a digital array. The method comprises four steps of conventional formation of a sum beam, interference airspace direction finding of a beam domain, construction of interference auxiliary beams and calculation of an adaptive weight; and specifically, the ADBF weight is calculated in a beam domain dimension reduction space for the auxiliary beams in the interference direction by using a digital array adaptive design. A theoretical analysis and a simulation result show that the algorithm adaptively inhibits interference, has good ultra-low side lobe beam shape preserving performance and is high in convergence rate, low in calculation quantity and suitable for the engineering application.

The invention provides an optimized radar task scheduling method of a digital array based on pulse interlacing. The method comprises the steps that 1) searching, tracking and imaging task models are established; 2) a reasonable and effective radar task priority is designed; and 3) a scheduling model is established, different radar imaging tasks are scheduled on the premise that the resource constraint is satisfied, whether an imaging task satisfies the expected imaging quality is determined, and a radar task to execute in a next scheduling interval is determined. The reasonable resource scheduling model which pulse interlacing reside in is established, objects are searched and tracked which ISAR imaging of sparse aperture cognition is carried out on part of precise tracking objects, the working efficiency of the radar is improved effectively, and a high-quality imaging effect is obtained.

The invention relates to the technical field of secondary radar, and discloses an amplitude and phase calibration method for radio frequency channels of digital array secondary radar and an antenna arrays. Different radio frequency channels of the digital array secondary radar and the antenna arrays carry out transmission and receiving at corresponding frequencies, and a relative amplitude and phase relationship between transmission beams and receiving beams of all radio frequency channels and the antenna arrays is determined under the condition that the different frequency channels of the digital array secondary radar and the antenna arrays carry out transmission and receiving at the corresponding frequencies; transmitting and receiving amplitude and phase characteristics of all radio frequency channels of the digital array secondary radar and the antenna arrays at the corresponding frequencies are calibrated according to a cross coupling relationship of the corresponding frequencies among the antenna arrays and by combining with the relative amplitude and phase relationship between the transmission beams and the receiving beams of all radio frequency channels of the digital array secondary radar and the antenna arrays at the corresponding frequencies.

The invention provides a method for dynamically setting a password by setting a graphic per se in a grid digital array. The method comprises the following steps of: setting the graphic, a counting point and a password point per se in the grid array with abscissas and ordinates, setting a positioning point and reference point arrangement sequence per se in the graphic, simultaneously performing password counting in any one of the eight directions of the grid digital array, transmitting a counted password into a computer server and storing the password as a graphic password; and moving the self-set graphic into the grid digital array with the abscissas and the ordinates, obtaining an abscissa and ordinate point and the password point in the moved graphic according to the self-set counting point, and obtaining the password every time the graphic is moved until meeting the requirement of a network on password digits to dynamically finish password login by the easily-remembered graphic capable of preventing the password from being detected. By the method for dynamically obtaining the password and finishing the login, even though the graphic is the same, the same password cannot be obtained due to different graphic positioning points, different counting points and different password points. Therefore, the password security of a user can be greatly and effectively protected, and sudden attacks from bogusware such as Trojan and the like, and different kinds of snooping and harassing attacks in front of automatic teller machines are prevented; and the method is easy to remember and operate, and highly preventive.

The invention discloses a method for synchronous transmission of digital array antenna baseband excitation data. The method is featured by small channel phase error, simple processing of digital processing part and low power consumption baseband excitation data. In the method, optical fiber is adopted as a long-distance transmission media between a collecting end and a receiving end, 1-N ADC1-ADCNof the collecting end perform data sampling on RF signals, and convert the signal into an intermediate frequency signal, packages data according to a JESD204B protocol and converts the data into a high-speed serial data flow, and sends the data flow to an electro-optical conversion module to be converted into optical signal, then an optical fiber photoelectric conversion module recovers the optical signal into an electric signal and sends the electric signal to the receiving end FPGA1-FPGAK to complete data recovery, then data is aligned through channel calibration, sample signals with data aligned are simultaneously transmitted to a received data processing end FPGA, and a full link data synchronous transmission homologous synchronous clock network synchronizes data.

The invention discloses a large-scale digital array signal synchronous acquisition system, and aims to provide a synchronous acquisition system which is high in reliability, expandable in scale, highin synchronization precision, good in amplitude consistency and phase consistency, rapid and stable. According to the system, each sub-array group is directly connected with a synchronous sampling analog-to-digital (A/D) converter through a high-speed serial interface at a collection end, synchronous sampling of array signals is achieved, a delay measurement module is triggered to perform phase relation detection through inter-sub-array synchronous moments, effective collection moment periods of synchronous signals are searched in a delay mode. Reliable alignment of sampling clocks and synchronizing signals is achieved through two-stage clock distribution and delay measurement in each sub-array, reference clocks and digital multi-beam synchronizing signals between the sub-arrays are transmitted and distributed to a DBF processing pool through optical fibers, and the DBF processing pool completes beam data aggregation according to the array scale. And the multi-beam data forming the full array are sent to baseband signal processing equipment to realize measurement, control and communication.

A digital radiographic tool with drive car for moving along track sections attached longitudinally to a pipe is shown. The drive car carries (1) a collimator on one side of the pipe for projecting x-rays or gamma rays on said pipe and (2) a linear digital array on an opposing side of the pipe for collecting x-rays or gamma rays that have passed through the pipe. The collected rays are processed to indicate any defects in the pipe. The digital radiographic tool is adjustable to allow inspection of pipes that have obstructions adjacent thereto.

The present invention provides a modular and building block type digital array radar system. The system comprises a plurality of building block type digital active transceiver sub-modules and a data fusion server. The building block type digital active transceiver sub-modules are respectively mounted on a preset antenna array-plane framework and are respectively connected with the data fusion server. Each building block type digital active transceiver sub-module is composed of an antenna radiation module in card-inserting type connection with a comprehensive backboard, a digital T/R module, a digital beam forming unit, an optical power divider and an array-plane monitoring network module, wherein the antenna radiation module, the digital T/R module, the digital beam forming unit and the optical power splitter are sequentially in communication connection. The optical power splitter is connected with the data fusion server. The array-plane monitoring network module is respectively connected with the digital T/R module and the data fusion server. The modular and building block type digital array radar system has the advantage of multi-angle viewing angle and can effectively resist the main-lobe interference. A distributed arrangement receiving station is passive and can effectively reduce the radar intercepted probability and the radar attacked probability.

The invention provides a digital formed beam design method of a digital array radar. The digital formed beam design method includes arranging M array elements vertically and evenly into an M array element linear array; taking an autocorrelation coefficient of an array weighting vector of the array element linear array as an optimal variable, and creating and solving a convex optimization model to acquire a globally optimal solution of an array pattern function amplitude square and a maximum ripple level of a forming region; comparing the maximum ripple level of the forming region with a required value of the maximum ripple level to judge whether an optimization result meets design requirements or not; if yes, performing spectral decomposition on the array pattern function amplitude square to acquire an optimal solution of the array weighting vector, and outputting the optimal solution as an optimal beam forming vector. The digital formed beam design method has the advantages that when the number of the array elements is small, good performance of an optimized pattern minor lobe level, the optimized maximum ripple level of the forming region and the like can be still kept, and algorithm complexity is low.

The invention belongs to the technical field of radar and discloses a communication radar integrated transmitting-receiving method based on a digital array antenna. The communication radar integrated transmitting-receiving method may simultaneous satisfy the performance requirements of communication and radar systems and comprises steps of: determining the transmitting wave beam weight vector of the digital array antenna; determining the transmitting signal waveform of the digital array antenna; adding a cyclic prefix to a constant-mode-value OFDM signal; multiplying the OFDM signal with the cyclic prefix by transmitting wave beam weight vector to complete signal transmission; acquiring the receiving data of the digital array antenna and determining the radar weight coefficient and the communication weight coefficient of the receiving end of the digital array antenna; obtaining a radar channel receiving signal according to the receiving data and the radar weight coefficient, and performing matched filtering on the radar channel receiving signal to obtain the distance information of a radar target; and obtaining a communication channel receiving signal according to the receiving data and the communication weight coefficient, and performing signal equalization coherent digital demodulation on the communication channel receiving signal successively so as to obtain a data bit stream transmitted by a communication base station.

The invention discloses application of FMCW system T/R unit in a digital phased array. The T/R unit comprises a radio frequency transmit-receive module, a digital waveform generator, a digital intermediate frequency receiver, an optical fiber communication module and a power supply module. The amplitude and phases of multipath DDS signals are controlled under a wave control instruction of the system, and radiofrequency signals are obtained through up conversion and radiated out through an antenna to form oriented transmit-receive wave beams in the air. The receiver converts the oriented transmit-receive wave beams into intermediate frequency signals through down conversion, and the digital intermediate frequency receiver suppresses emission leakage signals of FMCW through IF cancellation processing technology, thereby realizing transmit-receive isolation function of an FMCW radar system. Reception signal data flows are obtained by conducting IF digital sampling on target signals, and gathered to a terminal processing computer through a fiber interface to obtain digital reception wave beams, thereby realizing phased array radar function. The FMCW system T/R assembly is combined with digital array radar to obtain excellent distance resolution and doppler velocity measurement performances that are inherent characteristics of a FMCW radar system. The average power of a transmitter is greatly increased, and the detection performance of a digital phased array radar is improved.