LFM-PC signal and ambiguity function optimization method thereof

A technology of LFM-PC and ambiguity function, applied in the direction of radio wave reflection/re-radiation, using re-radiation, measuring devices, etc., can solve the problem of the reduction of the main-side lobe ratio of the filter output signal, the high-peak side-lobe of the waveform, and the research results Not many problems, to achieve the effect of increasing Doppler tolerance, good anti-interference performance, and Doppler tolerance

Active Publication Date: 2018-05-04
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology

The phase-encoded signal has a thumbtack-type ambiguity function, so it has good autocorrelation characteristics, but it is also sensitive to Doppler. Once the echo signal does not match the filter, the main-side lobe ratio of the filter output signal will decrease rapidly.
[0004] At present, many studies have been carried out on optimizing fuzzy functions, but the research results are not many
An optimization method based on minimizing the integrated sidelobe energy can be used. However, since the objective function is the integrated sidelobe energy, the optimized waveform may have a higher peak sidelobe

Method used

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  • LFM-PC signal and ambiguity function optimization method thereof
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  • LFM-PC signal and ambiguity function optimization method thereof

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Embodiment Construction

[0039] like figure 1 Shown, a kind of LFM-PC signal and its ambiguity function optimization method, comprise the following steps:

[0040] (1) The LFM-PC signal is obtained by modulating the LFM signal with the phase-encoded signal, and in the time domain, the two signals are directly multiplied; according to the definition of the ambiguity function, the ambiguity function χ of the LFM-PC signal u (τ,ξ) is

[0041]

[0042] Among them, τ is time, ξ is Doppler frequency, u PC (t) is the phase encoding signal, K=B L / T p is the FM slope, B L , T p are the bandwidth and duration of the LFM signal respectively; P is the code length, is the value of the nth sub-pulse, is a rectangular pulse p k (t) and p l The mutual ambiguity function of (t) can be expressed as:

[0043]

[0044] In the formula, t b is the sub-pulse width, and T p = Pt b ,

[0045] (2) Introduce vector and the sub-pulse mutual ambiguity function matrix H, where ψ is a 1×P-dimensional ve...

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Abstract

The invention discloses an LFM-PC signal and an ambiguity function optimization method thereof. The method comprises the steps that an optimization model is established based on a minimum peak sidelobe level criterion, the ambiguity function is optimized by adopting a sequential quadratic programming method, and the practicability of the method is examined through simulation. According to the LFM-PC signal and the ambiguity function optimization method thereof, a set of orthogonal phase-encoded signals are used as radar transmitted signals to improve anti-jamming performance of an SAR; compared with an LFM, the new signal has better anti-jamming performance, and compared with the phase-encoded signal, the new signal has a larger Doppler tolerance; the minimum peak sidelobe level criterionis adopted, and the ambiguity function is optimized by adopting the sequential quadratic programming method, so that the Doppler tolerance of the signal is enlarged.

Description

technical field [0001] The invention relates to the technical field of waveform optimization design, in particular to a linear frequency modulation and phase code composite modulation LFM-PC signal and an optimization method for its ambiguity function. Background technique [0002] The LFM signal is easy to generate and process and is not sensitive to Doppler, making it the most commonly used radar transmission signal. After decades of research and development, SAR imaging technology based on LFM signals has become mature and perfect. However, the anti-interference performance of LFM signal is poor, and it is impossible to achieve good imaging effect in today's increasingly fierce electronic countermeasures. [0003] Using a group of orthogonal phase coded signals as the radar transmission signal can improve the anti-jamming performance of SAR. The phase-encoded signal has a thumbtack-type ambiguity function, so it has good autocorrelation characteristics, but it is also s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S7/36G01S13/90
CPCG01S7/36G01S13/904
Inventor 张劲东陈婉迎张超徐乃清
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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