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95 results about "Parametric search" patented technology

In the design and analysis of algorithms for combinatorial optimization, parametric search is a technique invented by Nimrod Megiddo (1983) for transforming a decision algorithm (does this optimization problem have a solution with quality better than some given threshold?) into an optimization algorithm (find the best solution). It is frequently used for solving optimization problems in computational geometry.

LFMCW signal rapid detection and estimation method

The invention belongs to the technical field of radar signal analysis, and discloses an LFMCW signal rapid detection and estimation method. Quasi-coherent accumulation is performed on the LFM part of each period of the same modulation frequency in LFMCW signals according to PFRFT energy so that the signals are enabled to have great energy concentration characteristic in the PFRFT domain, i.e. the PFRFT of the signals has an obvious peak value in two sections. Firstly rapid period fractional order Fourier transform is performed on the linear frequency modulation continuous wave signals, the maximum modulus square of period fractional order Fourier transform act as a target function to establish an optimization model, and the optimization model is solved by using a genetic algorithm so that the optimal parameter estimation of the signals can be obtained. Four-dimensional parameter searching is performed on the PFRFT energy of the linear frequency modulation continuous wave signals by using the genetic algorithm so that detection and estimation of radar weak signals can be realized, the method is especially applied to the design of a signal analysis system of low interception probability radar and thus the theoretical and project application of the PFRFT algorithm can be realized.
Owner:UNIT 63892 OF PLA

Method for estimating cycle slope and starting frequency of hyperbolic frequency modulated signals

The invention discloses a method for estimating the cycle slope and the starting frequency of hyperbolic frequency modulated signals. The method comprises the following steps of first, acquiring a data sequence, second, initializing parameters, third, calculating the power spectrum of data in the ith short time window, fourth, estimating the instantaneous frequency fi of the data in the ith short time window by using a maximum gammagraphy method, fifth, estimating the zero crossing point interval gi = 1/fi of the data in the ith short time window, sixth, judging whether the data of all the short time windows are processed, executing the third step if not processed, otherwise executing the seventh step, seventh, sliding median filtering is conducted on a zero crossing point interval estimating sequence {gi, i = 1, 2, ..., I}, eighth, calculating the kth time interation weight, ninth, judging whether an interation stopping condition is met or not, if not, executing the eighth step again, otherwise executing the tenth step, and tenth, calculating the cycle slope and the starting frequency. According to the method, complex calculating and parametric search are of no need, the stability is strong, and quick and high-precision estimation of the parameters can be achieved.
Owner:SOUTHEAST UNIV

High-speed stealth target detection method of polynomial Hough Fourier transform

ActiveCN104808188AImplementing coherent accumulation detectionImprove discoveryRadio wave reradiation/reflectionDoppler spreadParametric search
The invention provides a high-speed stealth target detection method of the polynomial Hough Fourier transform, and aims at solving the problems in distance walk and Doppler expansion in accumulated detection of a high-speed maneuvering stealth target. The detection method comprises that polynomial models of relatively high resolution are established, energy accumulation of a parameter space is realized by the polynomial Hough Fourier transform, polynomial models of higher resolution are established according to a parameter corresponding to the maximal energy value of the parameter space, polynomial Hough Fourier transform of high resolution is then carried out in small areas and so on till the requirement for compensation precision is met, and thus, coherent accumulation detection for the high-speed maneuvering stealth target is realized. The searching train of thought is approached layer by layer via the multiple resolution levels of the polynomial models, accumulation detection for the target is realized by the provided polynomial Hough Fourier transform, and compared with multi-dimension parameter search in a large range in a traditional method, the computational complexity, the memory amount and the complex degree can be substantially decreased, and convenience is provided for engineering.
Owner:NAVAL AERONAUTICAL UNIV

Non-parametric-search radar maneuvering target long-term coherent integration method

ActiveCN109799488AEasy to handleAchieving coherent accumulationWave based measurement systemsParametric searchPeak value
The invention relates to a non-parametric-search radar maneuvering target long-term coherent integration method and belongs to the technical field of radar signal processing. The method includes the steps of firstly, performing Fourier transform on pulse-compressed radar data along distance to obtain distance frequency-interphase slow time two-dimensional data; performing non-uniform sampling order-reducing operation and time coordinate axis scale transform; thirdly, performing distance frequency inverse Fourier transform and non-uniform sampling slow time Fourier transform to allow a maneuvering target to form a peak value in a two-dimensional plane and achieve long-term coherent integration. The method has the advantages that high-order phase signals are reduced to first-order phase signals through one non-uniform sampling order-reducing operation, cross term influence is lowered as compared with a traditional gradual order-reducing method, and parameter estimation precision is increased; parametric search matching calculation is not needed, operation quantity is lowered, and the method is applicable to engineering; distance and high-order Doppler migration can be compensated atthe same time, long-term coherent integration can be achieved, and the maneuvering target detecting ability of a radar in a strong clutter background is increased.
Owner:NAVAL AVIATION UNIV +1

Hypersonic speed target detecting method for polynomial Radon-polynomial Fourier transform

The invention relates to a hypersonic speed target detecting method for polynomial Radon-polynomial Fourier transform, and belongs to the technical field of radar signal processing and detecting. The method comprises the steps that N periodic signals to be accumulated are sampled, a slow time-fast time target observed value is extracted, and pulse compression is performed on the sampled signals separately; initialization parameters of polynomial Radon-polynomial Fourier transform are determined; search, compensation and accumulation are performed in a parameter space through polynomial Radon-polynomial Fourier transform to obtain a range-Doppler distribution diagram subjected to phase-coherent accumulation; constant false-alarm detection and target motion parameter estimation are performed on the range-Doppler distribution diagram. According to the method, model building is performed on target motion through polynomial, range walk and Doppler spread of the signals are compensated through parameter search of the polynomial, and therefore effective accumulation detection on a high-speed high-mobility target can be achieved under a low signal-to-noise ratio background; in addition, effective search on the multi-dimensional parameter space is achieved in a multi-resolution search mode, and therefore the search real-time performance is improved.
Owner:NAVAL AVIATION UNIV

Radar high maneuvering target phase-coherent accumulation detection method based on time-reversed non-uniform sampling

The invention relates to a radar high maneuvering target phase-coherent accumulation detection method based on time-reversed non-uniform sampling, and belongs to the technical field of radar signal processing and detecting. The radar high maneuvering target phase-coherent accumulation detection method comprises the steps that first, radar echo pulse pressure is performed, time reversal is matchedwith Fourier transform, and slow time second-order phase compensation is performed; fast time dimension Fourier transform is performed to obtain distance frequency-slow time data, and frequency second-order phase compensation is performed; then, non-uniform sampling order reduction and variable scale scaling change are performed; inverse Fourier transform and the Fourier transform are performed inthe distance frequency and time dimension separately to realize long-term phase-coherent accumulation; and finally, the detection statistics are constructed to detect and estimate a maneuvering target. The radar high maneuvering target phase-coherent accumulation detection method can effectively accumulate maneuvering target signals with a high-order phase, compensate the distance and Doppler migration and improve the detection capability of the radar maneuvering target; meanwhile, the influence of a cross term of a traditional successive order reduction method is reduced, and the parameter estimation accuracy is improved; and no multi-dimensional motion parameter search matching calculation is needed, the amount of calculation is reduced, and the radar high maneuvering target phase-coherent accumulation detection method is suitable for engineering application.
Owner:NAVAL AVIATION UNIV +1
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