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A time-frequency second-order cross ambiguity function calculation method based on numerical fitting

A mutual ambiguity function and numerical fitting technology, applied in the field of signal parameter estimation, can solve problems such as large overhead, non-convergent iterations, and high search complexity, and achieve the effect of reducing complexity, reducing the number of sampling points and related operations

Inactive Publication Date: 2019-05-03
CHINA ELECTRONIC TECH GRP CORP NO 38 RES INST
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Problems solved by technology

However, when the prior knowledge is not obtained sufficiently, it may lead to the problem that the iteration does not converge or the search complexity is still very large.
Moreover, prior information requires long-term observation and complex pre-processing, which may bring large overhead

Method used

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  • A time-frequency second-order cross ambiguity function calculation method based on numerical fitting
  • A time-frequency second-order cross ambiguity function calculation method based on numerical fitting
  • A time-frequency second-order cross ambiguity function calculation method based on numerical fitting

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Embodiment 1

[0039] Such as figure 1 as shown, figure 1 It is a flow chart of the calculation method of the time-frequency second-order mutual ambiguity function based on numerical fitting according to the present invention; the calculation method of the time-frequency second-order mutual ambiguity function based on numerical fitting according to the present invention specifically includes the following steps:

[0040] S1, setting the initial time delay and frequency search parameters of the initial rough estimate; the set initial time delay and the frequency search parameters meet the theoretical error lower limit of the second-order mutual ambiguity function;

[0041] Wherein, the frequency search parameters include a frequency search step size f w_step ;For the initial delay search step size T s and the frequency search step size f w_step The setting of , combined with the specific background, is set according to the theoretical error lower limit of the second-order mutual ambiguity fu...

Embodiment 2

[0069] Regarding the symmetry of the second-order mutual ambiguity function in the frequency domain in the step S4, according to the definition of the second-order mutual ambiguity function and the search result expression of the final search, specifically,

[0070] signal x 1 (t) and x 2 The expression of the second-order mutual ambiguity function between (t) is:

[0071]

[0072] And the final estimated value of the delay difference of the final search and frequency difference final estimate by function The τ and f corresponding to the maximum value are given, that is, the search result of the final search The expression is:

[0073]

[0074] Therefore, the final search results can be obtained The final expression of is:

[0075]

[0076] Among them, D is the value of the delay difference within the search range; f D is the value of the frequency difference within the search range, Δf is the frequency deviation value; Δf can take any reasonable frequenc...

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Abstract

The invention discloses a time-frequency second-order cross ambiguity function calculation method based on numerical fitting. The time-frequency second-order cross ambiguity function calculation method comprises the following steps: setting time delay and frequency search parameters of initial coarse estimation; Obtaining a time delay difference initial estimation value and a frequency differenceinitial estimation value according to the time delay and frequency search parameters in combination with a second-order cross ambiguity function; carryinbg out Data sampling in the sampling range, andthe sampling frequency and a corresponding second-order mutual fuzzy function value are recorded to form a data set; Performing curve fitting by utilizing a radial basis function according to the data set to obtain a fitting function; In the sampling range, obtaining a frequency value corresponding to the maximum value obtained by the fitting function; Wherein the time delay difference initial estimation value and the frequency value are a time delay difference final estimation value and a frequency difference final estimation value of two paths of signals; According to the method, the symmetry of the second-order cross-ambiguity function in the frequency domain is utilized, the complexity of time-frequency joint estimation of the second-order cross-ambiguity function is reduced through double estimation of coarse estimation and fine estimation and a numerical fitting method, and fine estimation of the frequency difference is completed.

Description

technical field [0001] The invention relates to the technical field of signal parameter estimation, in particular to a calculation method for a time-frequency second-order mutual ambiguity function based on numerical fitting. Background technique [0002] As a new technology of radio reception, multi-antenna signal synthesis technology has been paid more and more attention by the government, military, industry and academia in many countries. In order to solve the problem of receiving extremely weak signals, it is proposed in the prior art to effectively combine the received signals of multiple antennas by randomly arranging multi-antenna signal synthesis technology, which is equivalent to the receiving results of larger aperture antennas, so as to complete the detection of signals from far away Effective reception of weak detection signals in space; using multi-antenna synthesis technology to effectively synthesize signals received by existing antennas can rapidly enhance si...

Claims

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Application Information

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IPC IPC(8): H04L25/02G06F17/15
Inventor 周家喜张正宇顾钰张靖张又文王晓涛彭立军
Owner CHINA ELECTRONIC TECH GRP CORP NO 38 RES INST
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