7 results about "Continuous wave interference" patented technology

The invention provides a composite material three-dimensional reconstruction detection system and method based on terahertz frequency-modulated continuous wave interference, and relates to the field of terahertz wave and frequency-modulated continuous wave interference ranging, the system comprises three optical fiber optical paths: a reference path, a comparison path and a measurement path, and terahertz frequency-modulated continuous wave signals are incident into a composite material to be detected; reflected return light is measured, the return light and local oscillation light interfere with each other, and a stable frequency difference exists between the return light and the local oscillation light, so that the depth of the return light reflected in the composite material can be determined by measuring the frequency of a terahertz beat frequency signal, and accurate position information of internal damage, defects and the like of the composite material can be detected. The composite material is subjected to body imaging through two-dimensional scanning, and finally the purpose of high-precision three-dimensional reconstruction nondestructive detection of internal defects and damage of the non-metallic composite material is achieved. Compared with other terahertz nondestructive testing technologies, the method has the advantages that the micron-level longitudinal detection resolution can be obtained, and the ranging and positioning precision of the internal defect damage of the composite material is greatly improved.

The present invention discloses a robust continuous wave interference and pulse interference joint suppression method, comprising the following steps: S1: data processing the signal received by the M array element array antenna of the receiver to obtain an intermediate frequency sampling signal, that is, a snapshot signal received in MK*1 dimension, wherein K is the number of time domain taps; S2: using the MK*1 dimension snapshot signal obtained in step S1 and adopting a robust covariance matrix estimation method. The present invention uses a robust covariance matrix estimation algorithm to replace the conventional sample covariance estimation algorithm when using a space-time two-dimensional minimum power algorithm to suppress continuous wave interference, thereby eliminating the embodiment of pulse interference in the covariance matrix estimation result, and then, for the remaining pulse interference after continuous wave suppression, a robust interference suppression algorithm is used to suppress the pulse interference, thereby achieving the purpose of suppressing continuous wave interference and pulse interference at the same time without increasing the number of antenna array elements.

The present application provides a method and system for estimating the carrier center frequency of single-tone continuous-wave interference. The method includes: obtaining the carrier frequency data output by a frequency-locked loop; constructing a carrier frequency data sequence and a carrier frequency data time sequence; performing a fitting operation on the carrier frequency data sequence; performing an interpolation operation on the carrier frequency data to obtain a carrier frequency interpolation sequence; performing a difference operation on the carrier frequency interpolation sequence to obtain a carrier frequency difference sequence; determining the minimum value of the carrier frequency difference sequence; and estimating the carrier center frequency based on the minimum value of the carrier frequency difference sequence. The advantages of the present application are as follows: it can be applied to a single satellite platform; and accurate estimation of the carrier center frequency of single-tone continuous-wave interference can be achieved only by relying on signal processing methods.

The application discloses a frequency-modulated continuous wave radar noise reduction ranging method based on weighted normalization, mainly solves the problem of inaccurate frequency-modulated continuous wave radar ranging under frequency-modulated continuous wave interference and white noise background, and introduces a weighted normalization algorithm into a radar ranging framework, and proposes a radar noise reduction ranging method based on envelope weighted normalization.Under a traditional linear frequency-modulated continuous wave radar ranging model, a method of performing weighted normalization processing on a radar echo envelope interfered by noise is designed, compared with traditional linear frequency-modulated continuous wave radar ranging, the application can effectively reduce the influence of frequency-modulated continuous wave and white noise superimposed interference on the echo amplitude of the frequency-modulated continuous wave radar ranging signal, and effectively improves the ranging precision in combination with constant false alarm threshold detection.

The invention aims at innovating a wireless interference signal processing system and a wireless interference signal processing method. Two rocket continuous wave interference suppression methods based on an antenna specific signal emission sequence are matched. The first method comprises the steps that the initial state of the rockets is set to be a normally-open state, and antennas newly added to the midpoints of the two rockets transmit closed signals. When the continuous wave interference signal exists, the interfered rocket receives the closed signal firstly, and then the continuous wave interference signal is suppressed by means of the closed signal. According to the second method, the initial state of the rocket is set to be a closed state, the newly-arranged antenna transmits continuous wave signals, under the condition, the interfered rocket receives continuous wave interference signals firstly and then receives signal receiving starting signals, and the effect of continuous wave interference suppression is achieved through the difference of the successive receiving sequences. According to the invention, the problem of continuous wave signal interference during the simultaneous total test of the two carrier rockets is effectively solved, the spaceflight test environment is improved, and the test work quality and efficiency are improved.

The present invention aims to innovate a wireless interference signal processing system and method. The present invention is equipped with two rocket continuous wave interference suppression methods based on the antenna specific signal transmission order. The first method: set the initial state of the rocket to a normally open state, and the newly installed antenna at the midpoint of the two rockets transmits a closed signal. When there is a continuous wave interference signal, the interfered rocket will first receive the closed signal, and then suppress the continuous wave interference signal with this closed signal. The second method: set the initial state of the rocket to a closed state, and the newly installed antenna transmits a continuous wave signal. In this case, the interfered rocket will first receive the continuous wave interference signal, and then receive the signal reception start signal. Through such a difference in the order of receiving, the effect of continuous wave interference suppression is achieved. The present invention effectively solves the problem of continuous wave signal interference during the simultaneous total measurement of two launch vehicles, improves the aerospace test environment, and improves the quality and efficiency of test work.

The invention provides a single-tone continuous wave interference carrier center frequency estimation method and system. The method comprises the following steps: acquiring carrier frequency data output by a frequency locking loop; constructing a carrier frequency data sequence and a carrier frequency data time sequence; performing fitting operation on the carrier frequency data sequence; carrying out interpolation operation on the carrier frequency data to obtain a carrier frequency interpolation sequence; carrying out differential operation on the carrier frequency interpolation sequence to obtain a carrier frequency differential sequence; determining the minimum value of the carrier frequency difference sequence; and estimating the carrier center frequency according to the minimum value of the carrier frequency difference sequence. The method has the advantages that the method can be suitable for a single satellite platform; accurate estimation of the single-tone continuous wave interference carrier center frequency can be realized only by means of a signal processing method.