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 应用科技  2020, Vol. 47 Issue (3): 37-40, 45  DOI: 10.11991/yykj.201907006 0

### 引用本文

LI Huidong, ZHAO Zhongkai. A non-uniform interrupted-sampling jamming mode for LFM radar[J]. Applied Science and Technology, 2020, 47(3): 37-40, 45. DOI: 10.11991/yykj.201907006.

### 文章历史

A non-uniform interrupted-sampling jamming mode for LFM radar
LI Huidong, ZHAO Zhongkai
College of Information and Communication Engineering, Harbin Engineering University, Harbin 150001, China
Abstract: Based on the characteristics of non-uniform interrupted-sampling pulse width and unfixed periodicity, the interference effect of non-uniform interrupted-sampling interference mode is studied and analyzed. The analysis focµses on the jamming effects of uniform interrupted-sampling and non-uniform interrupted-sampling and the jamming effects of smart noise jamming on linear frequency modulation(LFM) signals under uniform interrupted-sampling. The analysis shows that the uniform interrupted-sampling jamming only has deception effect, while the non-uniform interrupted-sampling jamming not only has deception effect, but also has certain suppression effect. The signal amplitude of smart noise interference in uniform interrupted-sampling mode is uneven, and the peak-to-average ratio is high, while the signal of non-uniform interrupted-sampling interference is constant envelope signal with lower peak-to-average ratio. Simulation results of MATLAB show that the interference mode based on non-uniform interrupted-sampling can achieve better interference effect than that based on uniform interrupted-sampling, which verifies the correctness of theoretical analysis and has certain engineering value.
Keywords: LFM radar    radar jamming    deceptive jamming    suppressing interference    non-uniform interrupted-sampling    interrupted-sampling interference    smart noise interference    peak-to-average ratio

1 相关原理介绍 1.1 间歇采样干扰原理

 $x(t) = {\rm{rect}}\Bigg(\frac{t}{T}\Bigg){{\rm{e}}^{{\rm{j}}(2{\rm{{\text{π}} }}{f_0}t + k{\rm{{\text{π}} }}{t^2})}}$

 $p(t) = {\rm{rect}}\Bigg(\frac{t}{\tau }\Bigg) \cdot \sum\limits_{n = - \infty }^{ + \infty } {\delta (t - n{T_s}} )$

 ${x_s}(t) = x(t)p(t)$

 ${y_s}(t) = {x_s}(t)h(t)$

 $\begin{array}{c} {y_{sn}}(t) = \chi \left( {t, - n{f_s}} \right) = \\ {\rm{Sa}}[{\rm{{\text{π}} }}(n{f_s} + kt)(T - \left| t \right|)]\left( {1 - \dfrac{{\left| t \right|}}{T}} \right){{\rm{e}}^{{\rm{j{\text{π}} }}n{f_s}t}} \\ \end{array}$ (1)

 ${y_s}(t) = \sum\limits_{n = - \infty }^{ + \infty } {{y_{scn}}(t)} {\rm{ = }}\sum\limits_{n = - \infty }^{ + \infty } {\tau {f_s}{\rm{Sa}}({\rm{{\text{π}} }}n{f_s}\tau )} {y_{sn}}(t)$ (2)

1.2 灵巧噪声干扰原理

 $n\left( t \right) = I\left( i \right) + {\rm{j}}Q\left( i \right)$

 $y\left( t \right) = x\left( t \right)n\left( t \right)$
2 非均匀间歇采样干扰

 $p(t) = \sum\limits_{n = 0}^{ + \infty } {\left[ {\left. {{\rm{rect}}\Bigg(\frac{t}{{{\tau _n}}}\Bigg)\delta \left[ {t - 2\left( {{\tau _0} + {\tau _1} + {\tau _2} + ... + {\tau _n}} \right)} \right]} \right]} \right.}$

 $\begin{array}{c} {\rm{ }}{y_{sn}}(t) = \chi \left( {t' - \dfrac{1}{{2\left( {{\tau _0} + {\tau _1} + \cdots + {\tau _n}} \right)}}} \right) = \\ {\rm{Sa}}\Bigg[{\rm{{\text{π}} }}\Bigg(\dfrac{1}{{2\left( {{\tau _0} + {\tau _1} + \cdots + {\tau _n}} \right)}} + kt\Bigg)(T - \left| t \right|)\Bigg] \cdot \left( {1 - \dfrac{{\left| t \right|}}{T}} \right){{\rm{e}}^{\frac{{{\rm{j{\text{π}} }}nt}}{{2\left( {{\tau _0} + {\tau _1} + \cdots + {\tau _n}} \right)}}}} \\ \end{array}$ (3)

 ${y_s}(t) = \sum\limits_{n = 0}^{ + \infty } {\left[ {\frac{1}{2}{\rm{Sa}}\Bigg(\frac{{{\rm{{\text{π}} }}{\tau _n}}}{{2\left( {{\tau _0} + {\tau _1} + \cdots + {\tau _n}} \right)}}\Bigg){y_{sn}}(t)} \right]}$

 $t = - \frac{1}{{2\left( {{\tau _0} + {\tau _1} + \cdots + {\tau _n}} \right)k}}$ (4)

 $\Delta t = \frac{1}{{2\left( {{\tau _0} + {\tau _1} + \cdots + {\tau _n}} \right)k}} - \frac{1}{{2\left( {{\tau _0} + {\tau _1} + \cdots + {\tau _{n - 1}}} \right)k}}$ (5)

3 仿真结果