CN103278804A

CN103278804A - Waveguide over-the-horizon radar

Info

Publication number: CN103278804A
Application number: CN2013102399153A
Authority: CN
Inventors: 张永刚; 焦林; 张健雪
Original assignee: Individual
Current assignee: PLA Naval University of Engineering
Priority date: 2013-06-14
Filing date: 2013-06-14
Publication date: 2013-09-04
Anticipated expiration: 2033-06-14
Also published as: CN103278804B

Abstract

The invention discloses a waveguide over-the-horizon radar, which comprises: the sensor unit is used for measuring hydrometeorological data at least comprising sea surface water temperature, sea surface atmospheric temperature, wind speed and atmospheric humidity; calculating the atmosphere stability by calculating the Richardson number Ri and the scale length L' of the monon-Obukhov according to the environmental parameters acquired by the sensor unit; the waveguide calculation module is used for calculating the height of the waveguide and the atmospheric correction refractive index of the evaporation waveguide under the states of different atmospheric stability; the over-the-horizon evaluation module judges whether the current radar has over-the-horizon performance according to the waveguide height and the atmospheric correction refractive index output by the waveguide calculation module; when the radar over-the-horizon performance judging module works, the over-the-horizon evaluating module calculates the trapping frequency of the current waveguide according to the waveguide height and the atmosphere correction refractive index, and when the trapping frequency is larger than the natural frequency of the current radar and the waveguide height is higher than the radar antenna height, the current radar is judged to have over-the-horizon performance. Meanwhile, the size of the target in the beyond-the-horizon state can be accurately judged.

Description

A waveguide over-the-horizon radar

技术领域technical field

本发明涉及一种波导超视距雷达及其超视距判定方法。The invention relates to a waveguide over-the-horizon radar and an over-the-horizon judging method thereof.

背景技术Background technique

迄今为止，还是站得高看得远为指导思想，把对海雷达天线尽可能架到最高处，不论在船上还是海岸边的高山上都能看到这样的布置。因为地球曲率影响，雷达发出的电磁波和人眼睛所能看到光波一样都是直线传播，因此很难看到地球曲率外的任何东西。人们把这种现象叫做最大可视距离。如何能看到地球曲率外的超视距目标是人类一直探索和追求的梦想。本项发明就是利用了海面时常出现蒸发波导现象——即大气和海水相交的边界层形成一种波导管现象。让雷达天线发射的电磁波在波导管中传播，从而就克服了地球曲率影响探测到视距以外的超视距目标。So far, the guiding ideology is still to stand tall and see far away, and to set up the anti-sea radar antenna as high as possible. This arrangement can be seen no matter on a ship or on a high mountain on the coast. Due to the influence of the curvature of the earth, the electromagnetic waves emitted by the radar propagate in a straight line just like the light waves that the human eye can see, so it is difficult to see anything outside the curvature of the earth. People call this phenomenon the maximum viewing distance. How to see beyond the horizon beyond the curvature of the earth is a dream that human beings have been exploring and pursuing. This invention utilizes the evaporation waveguide phenomenon that often occurs on the sea surface—that is, the boundary layer where the atmosphere and seawater intersect forms a waveguide phenomenon. Let the electromagnetic wave emitted by the radar antenna propagate in the waveguide, thereby overcoming the influence of the curvature of the earth to detect the over-the-horizon target beyond the line-of-sight.

另外，选择导航雷达改进，主要是现今导航雷达普及率高，改进方便，导航雷达对夜间航行和雾天航行能起到关键性作用。本项发明正是为今后导航雷达改进、增加超视距预警功能提供技术支持。In addition, the choice of navigation radar improvement is mainly due to the high penetration rate of navigation radar and the convenience of improvement. Navigation radar can play a key role in night navigation and foggy navigation. This invention just provides technical support for the improvement of navigation radar and the increase of over-the-horizon warning function in the future.

发明内容Contents of the invention

本发明针对以上问题的提出，而研制的The present invention aims at the proposal of the above problems, and develops

一种波导超视距雷达，具有：A waveguide over-the-horizon radar has:

测量至少包括海表水温、海面大气温度、风速和大气湿度的水文气象数据的传感器单元；Sensor units for measuring hydrometeorological data including at least sea surface water temperature, sea surface air temperature, wind speed and atmospheric humidity;

根据所述传感器单元采集的所述环境参数，通过计算理查森数Ri和Monin-Obukhov尺度长度L’计算所述大气稳定度；在不同大气稳定度的状态下计算海面蒸发波导高度和海面蒸发波导的大气修正折射指数的波导计算模块；According to the environmental parameters collected by the sensor unit, calculate the atmospheric stability by calculating the Richardson number Ri and the Monin-Obukhov scale length L'; calculate the height of the sea surface evaporation waveguide and the height of the sea surface evaporation waveguide in the state of different atmospheric stability Atmospheric corrected refractive index waveguide calculation module;

根据所述波导计算模块输出的海面蒸发波导高度和大气修正折射指数，判定当前雷达是否具有超视距性能的超视距评估模模块；According to the sea surface evaporation waveguide height and the atmospheric correction refraction index output by the waveguide calculation module, determine whether the current radar has an over-the-horizon evaluation module of over-the-horizon performance;

工作时，所述的超视距评估模块根据所述波导高度和大气修正折射指数，计算当前海面蒸发波导的陷获频率，当所述陷获频率大于当前雷达的固有频率时，且波导高度高于雷达天线高度，判定当前雷达具有超视距性能。When working, the over-the-horizon evaluation module calculates the trapping frequency of the current sea surface evaporation waveguide according to the waveguide height and the atmospheric correction refraction index. When the trapping frequency is greater than the natural frequency of the current radar, and the waveguide height is high Based on the height of the radar antenna, it is determined that the current radar has over-the-horizon performance.

还具有雷达探测距离评估模块：通过比较不同传输距离的雷达回波功率与雷达的最小可检测信号功率：若在海面蒸发波导内部某个距离的雷达回波功率大于雷达的最小可检测信号功率，则当前距离为雷达的可探测距离。It also has a radar detection distance evaluation module: by comparing the radar echo power and the minimum detectable signal power of the radar at different transmission distances: if the radar echo power at a certain distance inside the sea evaporation waveguide is greater than the minimum detectable signal power of the radar, Then the current distance is the detectable distance of the radar.

还具有雷达测量误差评估模块：接收所述波导计算模块得出的当前海面蒸发波导高度和大气修正折射指数判断当前雷达的初始仰角是否大于零，根据射线理论计算在雷达天线发出的射线在多层波导空间（包括海面蒸发波导和空间波导）中传播的总长度和多层空间的总高度，与目标距雷达的实际距离和目标的视在高度进行比较，得到雷达测量的高度误差和距离误差。It also has a radar measurement error evaluation module: receiving the current sea surface evaporation waveguide height and atmospheric correction refraction index obtained by the waveguide calculation module to judge whether the initial elevation angle of the current radar is greater than zero, and calculate the ray emitted by the radar antenna in the multi-layer according to the ray theory The total length of propagation in the waveguide space (including the sea surface evaporation waveguide and the space waveguide) and the total height of the multi-layer space are compared with the actual distance from the target to the radar and the apparent height of the target to obtain the height error and distance error measured by the radar.

所述传感器系统的高度可调：根据所述波导计算模块计算出的海面蒸发波导高度和当前天线高度，升起或降下雷达天线，使所述雷达波在波导中传播。The height of the sensor system is adjustable: according to the height of the sea evaporation waveguide calculated by the waveguide calculation module and the current antenna height, the radar antenna is raised or lowered to make the radar wave propagate in the waveguide.

所述传感器系统的频率可变，根据所述超视距评估模模块计算出的当前海面蒸发波导的陷获频率，对自身频率进行的调整，使所述雷达频率大于当前海面蒸发波导的陷获频率。The frequency of the sensor system is variable, and according to the trapping frequency of the current sea surface evaporation waveguide calculated by the over-the-horizon evaluation module, the frequency of itself is adjusted so that the radar frequency is greater than the trapping frequency of the current sea surface evaporation waveguide frequency.

具有目标识别模块：通过雷达发射功率计算出雷达波在海面蒸发波导管中能量分布规律，对于超视距目标而言，根据回波强度除以雷达发射功率在波导管中的该点的能量，就可判断出超视距目标的大小，目标大小可分为大目标、中目标和小目标。With target identification module: Calculate the energy distribution law of radar waves in the sea surface evaporation waveguide through the radar transmission power. For over-the-horizon targets, divide the echo intensity by the energy of the point in the waveguide by the radar transmission power, The size of the over-the-horizon target can be judged, and the target size can be divided into large targets, medium targets and small targets.

所述波导计算模块计算理查森数Ri的计算公式为：The formula for calculating the Richardson number Ri by the waveguide calculation module is:

${R R}_{i i} = = \frac{g g}{T T} \cdot \cdot \frac{&PartialD; &PartialD; θ θ / / &PartialD; &PartialD; z z}{{((&PartialD; &PartialD; u u / / &PartialD; &PartialD; z z))}^{22}}$

当0<Ri<1时，当前大气处于中性或稳定状态，当Ri<0时，判定当前大气处于不稳定状态；When 0<Ri<1, the current atmosphere is in a neutral or stable state; when Ri<0, it is determined that the current atmosphere is in an unstable state;

Monion-Obukhov长度L’的计算公式为：The calculation formula of Monion-Obukhov length L' is:

$L^{'} = \frac{u^{*} &PartialD; u / &PartialD; T}{kg &PartialD; θ / &PartialD; T},$ 其中u^*为摩擦速度 $u^{*} = \sqrt{\frac{τ}{ρ}},$ τ是切应力； $L^{'} = \frac{u^{*} &PartialD; u / &PartialD; T}{kg &PartialD; θ / &PartialD; T},$ where u ^* is the friction velocity $u^{*} = \sqrt{\frac{τ}{ρ}},$ τ is the shear stress;

对于中性和稳定大气条件下（0<Ri<1）的海面蒸发波导高度：For sea surface evaporation duct heights in neutral and stable atmospheric conditions (0<Ri<1):

$Z^{*} = \frac{{ΔN}_{P}}{- 0.125 (\log_{e} (\frac{h_{1}}{h_{0}}) + \frac{5.2 h_{1}}{L^{'}}) - \frac{5.2 {ΔN}_{p}}{L^{'}}},$ 其中 $L^{'} = \frac{u^{*} &PartialD; u / &PartialD; T}{kg &PartialD; θ / &PartialD; T}$ $Z^{*} = \frac{{ΔN}_{P}}{- 0.125 (\log_{e} (\frac{h_{1}}{h_{0}}) + \frac{5.2 h_{1}}{L^{'}}) - \frac{5.2 {ΔN}_{p}}{L^{'}}},$ in $L^{'} = \frac{u^{*} &PartialD; u / &PartialD; T}{kg &PartialD; θ / &PartialD; T}$

Np为位折射指数，h₀为海面高度，h₀=0.00000015，h₁为传感器高度；Np is the bit refraction index, h ₀ is the sea surface height, h ₀ =0.00000015, h ₁ is the sensor height;

当z^*＜0时或

＞1时，则：when z ^* < 0 or

>1, then:

${Z Z}^{* *} = = \frac{{ΔN ΔN}_{P P} ((11 + + 5.2 5.2)) + + 0.65 0.65 {h h}_{11}}{- - 0.125 0.125 {log log}_{e e} ((\frac{{h h}_{11}}{{h h}_{00}}))}$

对于不稳定条件下（R_i＜0时）海面蒸发波导高度：For the height of the sea surface evaporation duct under unstable conditions (R _i < 0):

$Z^{*} = \frac{1}{\sqrt[4]{φ^{4} - \frac{18}{L^{'}} φ^{3}}}$ φ为通量廓线函数 $Z^{*} = \frac{1}{\sqrt[4]{φ^{4} - \frac{18}{L^{'}} φ^{3}}}$ φ is the flux profile function

其中 $φ = \frac{- 0.125 B}{{ΔN}_{p}},$ $B = \log_{e} [\frac{h_{1}}{h_{0}}] - ψ$ B为通量廓线参数，ψ为通量廓线函数；in $φ = \frac{- 0.125 B}{{ΔN}_{p}},$ $B = \log_{e} [\frac{h_{1}}{h_{0}}] - ψ$ B is the flux profile parameter, ψ is the flux profile function;

在稳定或中性大气状态下蒸发波导的大气修正折射指数为In a stable or neutral atmospheric state, the atmospherically corrected refractive index of the evaporation waveguide is

$M m ((h h)) = = {M m}_{s the s} + + \frac{h h}{88} - - [[\frac{0.125 0.125 {Z Z}^{* *}}{11 + + \frac{5.2 5.2 {Z Z}^{* *}}{{L L}^{' '}}}]] [[{log log}_{e e} ((\frac{{h h}_{00} + + h h}{{h h}_{00}})) - - \frac{5.2 5.2 h h}{{L L}^{' '}}]]$

在不稳定大气状态下，蒸发波导的大气修正折射梯为In the unstable atmosphere state, the atmosphere-corrected refraction gradient of the evaporation waveguide is

$M (h) = M_{s} + \frac{h}{8} - [\frac{0.125 Z^{*}}{φ (\frac{Z^{*}}{L^{'}})}] [\log_{e} (\frac{h_{0} + h}{h_{0}}) - ψ (\frac{Z^{*}}{L^{'}})],$ 其中Ms为在h₀高度的大气修正折射指数，可直接测量。 $m (h) = m_{the s} + \frac{h}{8} - [\frac{0.125 Z^{*}}{φ (\frac{Z^{*}}{L^{'}})}] [\log_{e} (\frac{h_{0} + h}{h_{0}}) - ψ (\frac{Z^{*}}{L^{'}})],$ where Ms is the atmospherically corrected refractive index at h ₀ altitude, which can be measured directly.

所述超视距评估模模块计算所述海面蒸发波导陷获电磁波的最大波长为：The maximum wavelength of the electromagnetic wave trapped by the sea surface evaporation waveguide calculated by the over-the-horizon evaluation module module is:

$λ_{\max} = \frac{8 \sqrt{2} \times 10^{- 3}}{3} \cdot {&Integral;}_{z_{0}}^{d} \sqrt{M (z) - M (d)} dz$ （m） $λ_{\max} = \frac{8 \sqrt{2} \times 10^{- 3}}{3} &Center Dot; {&Integral;}_{z_{0}}^{d} \sqrt{m (z) - m (d)} dz$ (m)

始终d为海面蒸发波导高度，即为所述Z*，z代表不同高度，M（z）为不同高度的大气修正折射指数，z₀为海面高度；Always d is the height of the evaporation waveguide on the sea surface, which is the Z*, z represents different heights, M(z) is the atmospheric corrected refraction index at different heights, and z ₀ is the height of the sea surface;

计算所述蒸发波导陷获电磁波的最低频率为：Calculate the minimum frequency at which the evaporation waveguide traps electromagnetic waves as:

$f_{\min} = \frac{c}{λ_{\max}} = \frac{79.49449}{{&Integral;}_{z_{0}}^{d} \sqrt{M (z) - M (d)} dz}$ （GHz）式中，c为光速（2.997925.10⁸m/s）。 $f_{\min} = \frac{c}{λ_{\max}} = \frac{79.49449}{{&Integral;}_{z_{0}}^{d} \sqrt{m (z) - m (d)} dz}$ (GHz) where c is the speed of light (2.997925.10 ⁸ m/s).

所述雷达探测距离评估模块的工作方法如下：The working method of the radar detection range evaluation module is as follows:

雷达接收的目标回波功率可以写成单程传播损失的形式：The target echo power received by the radar can be written in the form of one-way propagation loss:

P_r＝-8.55+10log₁₀(P_tσf²)+2G-L_s-L_a-2L_single P _r ＝-8.55+10log ₁₀ (P _t σf ² )+2G-L _s -L _a -2L _single

根据雷达接收理论，雷达的最小可检测信号功率为S_imin，由雷达接收机性能决定，According to the radar receiving theory, the minimum detectable signal power of the radar is _Simin , which is determined by the performance of the radar receiver,

${S S}_{i i min min} = = k k {T T}_{00} {B B}_{n no} {F f}_{00} {D D.}_{00} = = {kT kT}_{00} {B B}_{n no} {F f}_{00} {((\frac{{S S}_{00}}{{N N}_{00}}))}_{min min}$

k为波尔兹曼常数，k＝1.38×10^-23(J/K)；T为电阻温度，以绝对温度（K）计量，对于室温17℃，T＝T₀＝290K；B_n为设备的通带，

τ为脉冲宽度；F₀为接收机的噪声系数，为接收机输出端最小信噪比；k is Boltzmann's constant, k=1.38×10 ^-23 (J/K); T is the resistance temperature, measured in absolute temperature (K), for a room temperature of 17°C, T=T ₀ =290K; B _n is the equipment the passband,

τ is the pulse width; F ₀ is the noise figure of the receiver, is the minimum signal-to-noise ratio at the output of the receiver;

当接收到的功率P_r大于S_imin时，雷达才能可靠的发现目标，当P_r正好等于S_imin时，就得到雷达检测该目标的最大作用距离R_max，而P_r小于S_imin时，目标为雷达电磁盲区内。When the received power P _r is greater than _Simin , the radar can reliably find the target. When P _r is exactly equal to _Simin , the maximum range R _max for the radar to detect the target is obtained, and when P _r is less than _Simin , the target It is within the radar electromagnetic blind zone.

所述误差检测模块的工作方法如下：The working method of the error detection module is as follows:

应用射线理论，建立雷达测距和测高误差的评估模式—raytrace模式。Applying the ray theory, the evaluation mode of radar ranging and height measuring error—raytrace mode is established.

由Snell法则，α₂可通过下式获得，According to Snell's law, α ₂ can be obtained by the following formula,

$cos cos {α α}_{22} = = [[11 + + (({N N}_{11} - - {N N}_{22})) \times \times 1010^{- - 66} - - \frac{dir dir \cdot \cdot dh d h}{{r r}_{00} + + {h h}_{11}}]] cos cos {α α}_{11}$

dir为射线方向，当射线向上传播时，dir=1，当射线向下传播时，dir=-1，Ψ₁为射线弯曲角，dir is the direction of the ray, when the ray propagates upward, dir=1, when the ray propagates downward, dir=-1, Ψ ₁ is the bending angle of the ray,

${Ψ Ψ}_{11} = = \frac{22 (({N N}_{11} - - {N N}_{22})) \times \times 1010^{- - 66}}{tan the tan {α α}_{11} + + tan the tan {α α}_{22}}$

β为地心角，根据Abel,et.al,1982，β is the geocentric angle, according to Abel, et.al, 1982,

β₁＝Ψ₁+α₂-α₁ β ₁ ＝Ψ ₁ +α ₂ -α ₁

根据余弦定理，TRGAPP1表示射线在这一层空间的长度，可由下式获得According to the law of cosines, TRGAPP1 represents the length of the ray in this layer of space, which can be obtained by the following formula

${TRG TRG}_{APP app!!} = = \sqrt{{(({r r}_{00} + + {h h}_{11}))}^{22} + + {(({r r}_{00} + + {h h}_{22}))}^{22} - - 22 (({r r}_{00} + + {h h}_{11})) (({r r}_{00} + + {h h}_{22})) cos cos {β β}_{11}}$

通过迭代算出每一层的TRGAPP1和β₁，将所得结果进行累加，可得到射线在空间传播的总长度TRG_APP和总的地心角β_total；By iteratively calculating TRGAPP1 and β ₁ of each layer, and accumulating the obtained results, the total length TRG _APP and the total geocentric angle β _total of the ray propagating in space can be obtained;

${TAG TAG}_{APP app} = = {Σ Σ}_{l l = = 11}^{L L} {TRG TRG}_{APPl APPl}$

${β β}_{total total} = = {Σ Σ}_{l l = = 11}^{L L} {β β}_{11}$

目标距雷达的实际距离为TRG，由下式获得：The actual distance from the target to the radar is TRG, obtained by the following formula:

$TRG TRG = = \sqrt{{(({r r}_{00} + + {h h}_{REL REL}))}^{22} + + {(({r r}_{00} + + {h h}_{n no}))}^{22} - - 22 (({r r}_{00} + + {h h}_{REL REL})) (({r r}_{00} {+ + h h}_{n no})) cos cos {β β}_{total total}} \cdot \cdot$

则目标的距离误差为：Then the distance error of the target is:

TRGERR＝TRG_APP-TRGTRGERR=TRG _APP -TRG

目标的视在高度为THTAPP，使用4/3等效地球半径，将实际射线变成近似的直线，所得目标视在高度为：The apparent height of the target is THTAPP, using 4/3 of the equivalent earth radius to convert the actual ray into an approximate straight line, the resulting apparent height of the target is:

${THT THT}_{APP app} = = \sqrt{{[[44 / / 33 (({r r}_{00} + + {h h}_{REL REL}))]]}^{22} + + {TRG TRG}_{APP app}^{22} - - 22 [[44 / / 33 (({r r}_{00} + + {h h}_{REL REL}))]] {TRG TRG}_{APP app} cos cos {α α}_{00}} - - 44 / / 33 (({r r}_{00} + + {h h}_{n no}))$

即可获得目标的高度误差：The height error of the target can be obtained:

THTERR＝THT_APP-h_n THTERR＝THT _APP -h _n

利用上述公式，可用编制程序模拟射线在空间传播的程序来评估雷达测量的高度和距离误差。Using the above formula, the program that can be programmed to simulate the propagation of rays in space can be used to evaluate the height and distance errors of radar measurements.

由于采用了上述技术方案，本发明提供的对海波导超视距雷达，能有效利用海面时常出现的蒸发波导现象，实现超视距探测由于克服了地球曲率影响使对目标超视距警戒变为有效。本发明的目的是提高目标超视距监测有效性、可靠性，同时实现超视距目标大小的精确判定探测。Owing to having adopted above-mentioned technical scheme, the sea waveguide over-the-horizon radar provided by the present invention can effectively utilize the phenomenon of evaporation waveguide that often occurs on the sea surface, and realize over-the-horizon detection because it overcomes the influence of the curvature of the earth so that the over-the-horizon warning of the target becomes efficient. The purpose of the invention is to improve the effectiveness and reliability of target over-the-horizon monitoring, and at the same time realize the accurate determination and detection of the over-the-horizon target size.

附图说明Description of drawings

为了更清楚的说明本发明的实施例或现有技术的技术方案，下面将对实施例或现有技术描述中所需要使用的附图做一简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are only some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to these drawings without any creative effort.

图1为本发明的模块示意图Fig. 1 is the module schematic diagram of the present invention

图2为本发明波导计算模块的工作流程图Fig. 2 is the working flow diagram of the waveguide calculation module of the present invention

图3为本发明超视距评估模块工作流程图Fig. 3 is the working flow diagram of the over-the-horizon evaluation module of the present invention

图4为本发明雷达测量误差评估模块的工作原理图1Fig. 4 is the operating principle Fig. 1 of the radar measurement error evaluation module of the present invention

图5为本发明雷达测量误差评估模块的工作原理图2Fig. 5 is the operating principle Fig. 2 of the radar measurement error evaluation module of the present invention

图6为本发明实施例1中修正折射指数的示意图Figure 6 is a schematic diagram of the modified refractive index in Embodiment 1 of the present invention

图7为本发明实施例1中雷达单程船舶损失的空间分布图Figure 7 is a spatial distribution diagram of radar one-way ship loss in Embodiment 1 of the present invention

图8为本发明实施例1中雷达在不同传播环境下对不同高度目标的最大探测距离示意图Fig. 8 is a schematic diagram of the maximum detection distance of the radar in embodiment 1 of the present invention to targets at different heights in different propagation environments

图9为本发明实施例1中雷达在波导条件下获得的海岸线示意图Fig. 9 is a schematic diagram of the coastline obtained by radar under waveguide conditions in Embodiment 1 of the present invention

图10为本发明实施例1中船舶的航海图Fig. 10 is the nautical chart of the ship in Embodiment 1 of the present invention

图11为本发明雷达在海面蒸发波导中传播的示意图Fig. 11 is the schematic diagram of radar propagating in sea surface evaporation waveguide for the present invention

具体实施方式Detailed ways

为使本发明的实施例的目的、技术方案和优点更加清楚，下面结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚完整的描述：In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the drawings in the embodiments of the present invention:

一种波导超视距雷达，主要包括：波导计算模块和超视距评估模块。A waveguide over-the-horizon radar mainly includes: a waveguide calculation module and an over-the-horizon evaluation module.

传感器单元能够测量并提供至少包括温度、大气温度、风速和大气湿度等多种水文气象数据。The sensor unit is capable of measuring and providing at least various hydrometeorological data including temperature, atmospheric temperature, wind speed and atmospheric humidity.

波导计算模块能够根据所述提供的所述多种水温气象数据，通过计算理查森数Ri和Monin-Obukhov尺度长度L’计算所述大气稳定度并且能够在计算得出的不同大气稳定度的状态下计算波导高度和蒸发波导的大气修正折射指数。The waveguide calculation module can calculate the atmospheric stability by calculating the Richardson number Ri and the Monin-Obukhov scale length L' according to the various water temperature and meteorological data provided, and can calculate the atmospheric stability under different atmospheric stability conditions. Computes the waveguide height and the atmospherically corrected refractive index for the evaporation waveguide.

超视距评估模模块用于接收并根据所述波导计算模块输出的波导高度和大气修正折射指数，判定当前雷达是否具有超视距性能。The over-the-horizon evaluation module is used to receive and determine whether the current radar has over-the-horizon performance according to the waveguide height and atmospheric correction refractive index output by the waveguide calculation module.

工作状态下，所述的传感器单元首先获取当前的水文气象数据，将数据传送至所述的波导计算单元，波导计算单元根据水文气象数据计算出当前环境中的大气波导高度和大气修正折射指数并传送至所述的超视距评估模块；由超视距评估模块根据所述波导高度和大气修正折射指数，计算当前波导的陷获频率，当所述陷获频率大于当前雷达的固有频率时，且波导高度高于雷达天线高度，判定当前雷达具有超视距性能，控制雷达进行超视距搜索，获得相应的超视距搜索数据。In the working state, the sensor unit first obtains the current hydrometeorological data, and transmits the data to the waveguide calculation unit, and the waveguide calculation unit calculates the atmospheric waveguide height and the atmospheric correction refractive index in the current environment according to the hydrometeorological data and Transmit to the described over-the-horizon assessment module; By the over-the-horizon assessment module, calculate the trapping frequency of the current waveguide according to the waveguide height and atmospheric correction index, when the trapping frequency is greater than the natural frequency of the current radar, And if the height of the waveguide is higher than the height of the radar antenna, it is determined that the current radar has over-the-horizon performance, and the radar is controlled to perform over-the-horizon search to obtain corresponding over-the-horizon search data.

进一步的，所述波导计算单元计算波导高度和大气修正折射指数主要采用以下的方法：Further, the waveguide calculation unit mainly adopts the following methods to calculate the waveguide height and atmospheric correction refractive index:

对于中性和稳定大气条件下（0<Ri<1）的蒸发波导高度：For evaporation duct heights in neutral and stable atmospheric conditions (0<Ri<1):

当z^*＜0时或

＞1时，则：when z ^* < 0 or

>1, then:

对于不稳定条件下（R_i＜0时）蒸发波导高度：For the height of the evaporation waveguide under unstable conditions (R _i <0):

${Z Z}^{* *} = = \frac{11}{\sqrt[44]{{φ φ}^{44} - - \frac{1818}{{L L}^{' '}} {φ φ}^{33}}}$

其中 $φ = \frac{- 0.125 B}{{ΔN}_{p}},$ $B = \log_{e} [\frac{h_{1}}{h_{0}}] - ψ$ in $φ = \frac{- 0.125 B}{{ΔN}_{p}},$ $B = \log_{e} [\frac{h_{1}}{h_{0}}] - ψ$

在稳定或中性大气状态下蒸发波导的大气修正折射梯度为The atmosphere-corrected refraction gradient of the evaporation waveguide in a stable or neutral atmosphere is

$M m ((h h)) = = {M m}_{s the s} + + \frac{h h}{88} - - [[\frac{0.125 0.125 {Z Z}^{* *}}{φ φ ((\frac{{Z Z}^{* *}}{{L L}^{' '}}))}]] [[{log log}_{e e} ((\frac{{h h}_{00} + + h h}{{h h}_{00}})) - - ψ ψ ((\frac{{Z Z}^{* *}}{{L L}^{' '}}))]] \cdot \cdot$

在海洋蒸发波导研究中，常常使用伪折射率Np的概念，即In the study of ocean evaporation ducts, the concept of pseudo-refractive index Np is often used, namely

${N N}_{p p} = = 77.6 77.6 \frac{{P P}_{00}}{θ θ} + + 3.73 3.73 \times \times 1010^{66} \frac{{e e}_{p p}}{{θ θ}^{22}}$

式中：θ为位温，与大气温度关系为θ＝T(P₀/P)^0.286(K)；In the formula: θ is the potential temperature, and the relationship with the atmospheric temperature is θ=T(P ₀ /P) ^0.286 (K);

e_p位水汽压，与水汽压的关系为e_p＝e·P₀/PThe relationship between the water vapor pressure at e _p position and the water vapor pressure is e _p = e·P ₀ /P

近地层中，P≈P₀，θ≈T，e_p=e，则公式变为In the near-surface layer, P≈P ₀ , θ≈T, e _p =e, then the formula becomes

${N N}_{p p} = = 77.6 77.6 \frac{{P P}_{00}}{T T} 3.73 3.73 \times \times 1010^{66} \frac{e e}{{T T}^{22}}$

超视距评估模模块计算所述蒸发波导陷获电磁波的最大波长主要采用的方法为：The main method used by the over-the-horizon evaluation module to calculate the maximum wavelength of the electromagnetic wave trapped by the evaporation waveguide is:

在得到f_min后，与雷达系统自身的频率进行比较，若当前雷达的频率大于f_min则判定当前雷达具有超视距性能，雷达开始进行超视距搜索；若雷达的频率小于f_min，则表示当前雷达不具有超视距性能，无法进行超视距搜索。After f _min is obtained, it is compared with the frequency of the radar system itself. If the current radar frequency is greater than f _min , it is determined that the current radar has over-the-horizon performance, and the radar starts over-the-horizon search; if the radar frequency is less than f _min , then Indicates that the current radar does not have over-the-horizon performance and cannot perform over-the-horizon search.

在考虑雷达是否在当前波导环境具有超视距系能，还需要考虑当前波导高度和雷达天线高度的关系，只有当前波导具有高度且高于雷达天线高度时，雷达才能够根据陷获频率对雷达超视距进行判断。When considering whether the radar has over-the-horizon capability in the current waveguide environment, it is also necessary to consider the relationship between the current waveguide height and the radar antenna height. Only when the current waveguide has a height and is higher than the radar antenna height can the radar detect the radar according to the trapping frequency. Judging beyond the horizon.

在判定当前雷达具有超视距性能后，还需要对超视距的雷达性能进行评估，作为一个较佳的实施方式，本发明还具有雷达探测距离评估模块：After judging that the current radar has over-the-horizon performance, it is also necessary to evaluate the over-the-horizon radar performance. As a preferred embodiment, the present invention also has a radar detection distance evaluation module:

通过比较不同传输距离的雷达回波功率与雷达的最小可检测信号功率：若某个距离的雷达回波功率大于雷达的最小可检测信号功率，则当前距离为雷达的可探测距离。By comparing the radar echo power and the minimum detectable signal power of the radar at different transmission distances: if the radar echo power at a certain distance is greater than the minimum detectable signal power of the radar, the current distance is the detectable distance of the radar.

进一步的，该雷达探测距离评估模块采用如下方法对探测距离进行评估。雷达接收的目标回波功率可以写成单程传播损失的形式：Further, the radar detection distance evaluation module adopts the following method to evaluate the detection distance. The target echo power received by the radar can be written in the form of one-way propagation loss:

${S S}_{i i min min} = = {kT kT}_{00} {B B}_{n no} {F f}_{00} {D D.}_{00} = = {kT kT}_{00} {B B}_{n no} {F f}_{00} {((\frac{{S S}_{00}}{{N N}_{00}}))}_{min min}$

τ为脉冲宽度；F₀为接收机的噪声系数，

为接收机输出端最小信噪比，也称为检测因子D₀，它由发现概率P_d和虚警概率P_fa决定，雷达探测因子由以下公式决定，对于非相参的脉冲积累方式有：k is Boltzmann's constant, k=1.38×10 ^-23 (J/K); T is the resistance temperature, measured in absolute temperature (K), for a room temperature of 17°C, T=T ₀ =290K; B _n is the equipment the passband,

τ is the pulse width; F ₀ is the noise figure of the receiver,

is the minimum signal-to-noise ratio at the output of the receiver, also known as the detection factor D ₀ , which is determined by the detection probability P _d and the false alarm probability P _fa , and the radar detection factor is determined by the following formula. For non-coherent pulse accumulation methods:

${D D.}_{00} = = \frac{{L L}_{f f} {x x}_{00}}{{44 N N}_{p p}} ((11 + + \sqrt{11 + + \frac{{1616 N N}_{p p}}{{x x}_{00}}}))$

x₀＝(g_fa+g_d)² x ₀ ＝(g _fa +g _d ) ²

${g g}_{fa fa} = = 2.36 2.36 \sqrt{- - {log log}_{1010} (({P P}_{fa fa}))} - - 1.02 1.02$

${g g}_{d d} = = 1.23 1.23 t t / / \sqrt{11 - - {t t}^{22}}$

t＝0.9(2P_d-1)t=0.9(2P _d -1)

而对于相参的脉冲积累方式则有：For the coherent pulse accumulation methods, there are:

${D D.}_{00} = = \frac{{L L}_{f f} {x x}_{00}}{{44 N N}_{p p}} ((11 + + \sqrt{11 + + \frac{1616}{{x x}_{00}}}))$

L_f为目标波动损耗，对于无波动目标（斯威尔林模型0）有：L_f＝1，对于波动目标（如斯威尔林模型1、chi平方律等类型）有：L _f is the target fluctuation loss, for non-fluctuating targets (Swelling model 0): L _f = 1, for fluctuating targets (such as Swelling model 1, chi square law, etc.):

L_f＝-(ln(P_d)(1+g_d/g_fa)^-1。L _f =-(ln(P _d )(1+g _d /g _fa ) ^-1 .

N_p为脉冲积累数，由雷达的基本参数决定，对于机械扫描的雷达：N _p is the number of accumulated pulses, which is determined by the basic parameters of the radar. For mechanically scanned radars:

${N N}_{p p} = = \frac{{Θ Θ}_{H h} {f f}_{p p}}{{66 φ φ}_{h h} cos cos {θ θ}_{00}},,$

其中，Θ_H是天线水平波束宽度，度；f_p是脉冲重复频率，Hz；φ_h是天线水平方向扫描速度，rpm；θ₀是目标仰角，度（对于低空目标近似为0度）；而对于电扫描的雷达，脉冲积累数则由程序设定。Among them, Θ _H is the horizontal beam width of the antenna, degrees; f _p is the pulse repetition frequency, Hz; φ _h is the scanning speed of the antenna in the horizontal direction, rpm; θ ₀ is the target elevation angle, degrees (approximately 0 degrees for low-altitude targets); For electronically scanned radars, the number of pulse accumulations is set by the program.

雷达最小可检测信号写成dB形式为：The minimum detectable signal of the radar is written in dB as:

S_imin＝kT₀B_nF₀D₀＝-143.98+10log₁₀B_n+F₀+10log₁₀(D₀)S _imin ＝kT ₀ B _n F ₀ D ₀ ＝-143.98+10log ₁₀ B _n +F ₀ +10log ₁₀ (D ₀ )

B_n的单位：MHz。假设雷达检测受系统噪声的影响，则当接收到的功率P_r大于S_imin时，雷达才能可靠的发现目标，当P_r正好等于S_imin时，就得到雷达检测该目标的最大作用距离R_ma，而P_r小于S_imin时，目标为雷达电磁盲区内。Unit of B _n : MHz. Assuming that radar detection is affected by system noise, the radar can reliably detect the target when the received power P _r is greater than _Simin , and when P _r is exactly equal to _Simin , the maximum range R _ma for the radar to detect the target is obtained , and when P _r is less than _Simin , the target is in the radar electromagnetic blind zone.

更进一步的，考虑到大气波导分布的不均匀性，在传统的雷达扫描区域中可能会出现多个分布不均，形状不均的盲区。故作为一个较佳的实施方式，本发明还设有雷达扫描区域判定模块，在雷达的雷达扫描区域中划分网格，应用上述判断雷达超视距探测距离的方法计算每个网格节点的雷达回波功率；遍历全部的网格节点，将全部网格节点的回波功率与雷达的最小可检测信号功率进行比较：若某个所述的网格节点返回的回波功率小于所述雷达的最小可检测信号功率，则当前网格节点为雷达探测盲点；遍历所有网格节点，即可最终得到当前雷达的检测区域和检测盲区。Furthermore, considering the inhomogeneity of the distribution of atmospheric ducts, there may be multiple blind spots with uneven distribution and uneven shapes in the traditional radar scanning area. Therefore, as a preferred embodiment, the present invention is also provided with a radar scanning area judging module, which divides the grid in the radar scanning area of the radar, and applies the above-mentioned method for judging the radar over-the-horizon detection distance to calculate the radar of each grid node. Echo power; traverse all grid nodes, compare the echo power of all grid nodes with the minimum detectable signal power of the radar: if the echo power returned by a certain grid node is less than the radar’s The minimum detectable signal power means that the current grid node is the radar detection blind spot; traversing all the grid nodes can finally obtain the current radar detection area and detection blind area.

更进一步的，本发明还设有针对多层大气波导情况下，对雷达超视距的检测结果进行判定的雷达测量误差评估模块。Furthermore, the present invention is also provided with a radar measurement error evaluation module for judging the detection results of the radar over-the-horizon in the case of a multi-layer atmospheric waveguide.

接收所述波导计算模块得出的当前波导高度和大气修正折射指数判断当前雷达的初始仰角是否大于零，根据射线理论计算在雷达天线发出的射线在多层空间中传播的总长度和多层空间的总高度，与目标距雷达的实际距离和目标的视在高度进行比较，得到雷达测量的高度误差和距离误差。采用的具体方法如下：应用射线理论，建立雷达测距和测高误差的评估模式—raytrace模式。Receive the current waveguide height and atmospheric correction refractive index obtained by the waveguide calculation module to determine whether the initial elevation angle of the current radar is greater than zero, and calculate the total length and multi-layer space of the rays emitted by the radar antenna in the multi-layer space according to the ray theory The total height of the target is compared with the actual distance from the target to the radar and the apparent height of the target to obtain the height error and distance error measured by the radar. The specific method adopted is as follows: apply the ray theory, and establish the evaluation mode of radar distance measurement and height measurement error—raytrace mode.

β₁＝Ψ₁+α₂-α₁ β ₁ ＝Ψ ₁ +α ₂ -α ₁

通过迭代算出每一层的TRGAPP1和β₁，将所得结果进行累加，可得到射线在空间传播的总长度TRG_APP和总的地心角β_total，如图示。TRGAPP1 and β ₁ of each layer are iteratively calculated, and the results are accumulated to obtain the total length TRG _APP of rays propagating in space and the total geocentric angle β _total , as shown in the figure.

${TAG TAG}_{APP app} = = {Σ Σ}_{l l = = 11}^{L L} {TRG TRG}_{APPl APPl}$

${β β}_{total total} = = {Σ Σ}_{l l = = 11}^{L L} {β β}_{11}$

目标距雷达的实际距离为TRG，可由下式获得：The actual distance between the target and the radar is TRG, which can be obtained by the following formula:

$TRG TRG = = \sqrt{{(({r r}_{00} + + {h h}_{REL REL}))}^{22} + + {(({r r}_{00} + + {h h}_{n no}))}^{22} - - 22 (({r r}_{00} + + {h h}_{REL REL})) (({r r}_{00} {+ + h h}_{n no})) cos cos {β β}_{total total}} \cdot &Center Dot;$

则目标的距离误差为：Then the distance error of the target is:

TRGERR＝TRG_APP-TRGTRGERR=TRG _APP -TRG

THTERR＝THT_APP-h_n THTERR＝THT _APP -h _n

进一步的，所述的雷达天线的高度可升降，可以根据当前大气波导的高度，在一定的范围内实时调节雷达天线的高度，以保证当前的雷达具有超视距性能。Further, the height of the radar antenna can be raised and lowered, and the height of the radar antenna can be adjusted in real time within a certain range according to the height of the current atmospheric waveguide, so as to ensure that the current radar has beyond-the-horizon performance.

相应的，本发明的雷达为频率可变雷达，可改变自身的波段（频率），以适应不同大气波导环境的陷获频率，尽可能的保证雷达具有超视距探测性能。Correspondingly, the radar of the present invention is a frequency-variable radar, which can change its own band (frequency) to adapt to the trapping frequency of different atmospheric waveguide environments, so as to ensure that the radar has over-the-horizon detection performance as much as possible.

实施例1Example 1

使用小功率的导航雷达（“古野”RF-7100D），其基本性能参数见下表：Using a low-power navigation radar ("Furuno" RF-7100D), its basic performance parameters are shown in the table below:

杭州湾外海（30o35’N，122o37’E）附近，正北航行。14:00开始通过测量大气温度（19.8℃）、湿度（43%）、海表水温（18℃）和海面风速（10.4m/s）等要素，监测到船舶所在海域存在可利用的蒸发波导，波导高度为30.18m，其修正折射指数廓线结构如图6所示。Near Hangzhou Bay (30o35’N, 122o37’E), sailing due north. At 14:00, by measuring atmospheric temperature (19.8°C), humidity (43%), sea surface water temperature (18°C) and sea surface wind speed (10.4m/s), it was detected that there was an available evaporation waveguide in the sea area where the ship was located. The waveguide height is 30.18m, and its modified refractive index profile structure is shown in Figure 6.

数据处理过程data processing

利用PEM-SSFA综合数值模式，对实测蒸发波导环境下雷达电磁波进行数值计算，得到的单程传播损失的空间分布，如图7所示。这里将单点实测的蒸发波导环境作为雷达探测区域的单一环境是一种近似处理，这种近似在开阔海域或者说大气水平均匀性良好的海域是合理的。可以看出：蒸发波导高度大于雷达天线高度，出现“陷获”传播特征，波导层内传播损失小于标准大气环境下，雷达容易出现低空超视距探测。Using the PEM-SSFA comprehensive numerical model, the numerical calculation of the radar electromagnetic waves in the measured evaporative waveguide environment is carried out, and the spatial distribution of the one-way propagation loss is obtained, as shown in Figure 7. It is an approximation to regard the single-point measured evaporation duct environment as the single environment of the radar detection area, and this approximation is reasonable in open seas or seas with good horizontal uniformity of the atmosphere. It can be seen that the height of the evaporative waveguide is greater than the height of the radar antenna, and the propagation characteristics of "trapping" appear. The propagation loss in the waveguide layer is smaller than that in the standard atmospheric environment, and the radar is prone to low-altitude over-the-horizon detection.

雷达主要探测海面的船舶目标，假定目标为大型船舶，RCS为20000m²，目标无起伏或慢起伏。雷达虚警概率为10-6，探测概率要求为0.9，利用传播损耗计算公式得到传播损失门限阈值T_single为139.1dB。利用这一门限值对图7的传播损失空间分布进行阈化处理，得到雷达对大型船舶目标的探测概率空间分布，实际上，单门限值阈值处理的结果只有“能”和“不能”探测到目标两种结果。The radar mainly detects ship targets on the sea surface. It is assumed that the target is a large ship with an RCS of 20,000m ² and the target has no or slow fluctuations. The radar false alarm probability is 10-6, and the detection probability requirement is 0.9. Using the propagation loss calculation formula, the propagation loss threshold T _single is 139.1dB. Use this threshold value to threshold the spatial distribution of propagation loss in Figure 7 to obtain the spatial distribution of radar detection probability of large ship targets. In fact, the results of single threshold threshold processing are only "can" and "cannot". There are two results of detecting the target.

对于指定目标高度的单门限阈化处理，可以直接对该指定高度上单程传播损失随距离分布中进行雷达最大探测距离的评估。从图7中分别提取17.5m和25m高度上的计算结果得到单程传播损失随距离的变化，如图8中圆标志和框标志实线所示。为了与标准大气环境下进行对比，数值计算标准大气环境下的传播损失的空间分布，同样提取17.5m和25m两个高度上传播损失随距离的变化，如图8中三角标志和正号标志虚线所示。满足探测概率和虚警概率所要求的门限为139.1dB，如图8中的无标志线。图8中可以分析雷达在不同传播环境下对不同高度目标的最大探测距离（门限直线与传播损失距离变化曲线最远相交的距离）。For single-threshold thresholding at a specified target height, the radar maximum detection range can be directly evaluated from the distribution of one-way propagation loss with distance at the specified height. Extract the calculation results at heights of 17.5m and 25m from Figure 7 to obtain the variation of one-way propagation loss with distance, as shown by the circle mark and the solid line of the frame mark in Figure 8. In order to compare with the standard atmospheric environment, numerically calculate the spatial distribution of the propagation loss in the standard atmospheric environment, and also extract the variation of the propagation loss with the distance at the two heights of 17.5m and 25m, as shown by the dotted line of the triangle mark and the plus sign in Figure 8 Show. The threshold required to meet the detection probability and false alarm probability is 139.1dB, as shown in Figure 8 without a marker line. In Figure 8, the maximum detection distance of the radar to targets at different heights under different propagation environments can be analyzed (the farthest intersection distance between the threshold straight line and the propagation loss distance change curve).

由于雷达主要探测海面的船舶目标，通常以船舶有效高度以下所有高度上的最大探测距离中最大一个作为雷达性能评估的结果，从图8的数值计算结果可以看出，雷达在试验蒸发波导环境下，在17.5m高度上具有最大探测距离。下表说明了雷达对17.5m高度目标在不同传播环境下的探测能力对比。Since the radar mainly detects ship targets on the sea surface, the maximum detection distance at all heights below the effective height of the ship is usually used as the result of radar performance evaluation. From the numerical calculation results in Fig. , with a maximum detection range at a height of 17.5m. The following table illustrates the comparison of the radar's detection capabilities for targets at a height of 17.5m in different propagation environments.

表中雷达视距R_hor是利用视距方程算得到，是雷达视距探测的理想最大作用距离，为35.2km；标准大气环境下满足虚警率10-6、探测概率0.9条件下雷达的最大距离，为25.4km；而实测的蒸发波导环境下，评估雷达能够探测80.1km处的大型船舶目标，远远超出理想视距和标准大气环境下的探测距离。The radar line-of-sight R _hor in the table is calculated by using the line-of-sight equation, which is the ideal maximum operating distance of radar line-of-sight detection, which is 35.2km; under the standard atmospheric environment, the radar’s maximum detection rate is 10-6 and detection probability is 0.9 The distance is 25.4km; and under the measured evaporative waveguide environment, the evaluation radar can detect large ship targets at 80.1km, which is far beyond the detection distance under the ideal line-of-sight and standard atmospheric environment.

试验过程中，导航雷达观测到了大量视距外的目标回波，表中还列举了雷达观测到的典型海上船舶目标（上海港外的大型船只）。事实上，雷达还观测到了大量100km外的海面岛屿、建筑及地形回波，典型的如观测到127.8km外的东方明珠电视塔、124.1km外的金山回波等，探测实物照片如图9所示，船舶所处的位置如图10所示。During the test, the navigation radar observed a large number of target echoes beyond the visual range, and the table also lists typical maritime ship targets (large ships outside Shanghai Port) observed by the radar. In fact, the radar also observed a large number of sea islands, buildings, and terrain echoes 100km away. Typical examples include the Oriental Pearl TV Tower 127.8km away, and Jinshan echoes 124.1km away. The actual detection photos are shown in Figure 9 , the position of the ship is shown in Figure 10.

此处即为本发明一个意想不到的技术效果，即能够准确的获得海岸线的轮廓，可以在海面蒸发波导存在的情况下，精确的探测海岸线的轮廓，方便船只及时规避。Here is an unexpected technical effect of the present invention, that is, the outline of the coastline can be accurately obtained, and the outline of the coastline can be accurately detected in the presence of the sea surface evaporation waveguide, so that ships can avoid it in time.

从雷达最大探测距离评估结果与雷达实际探测效果的比较来看，两者吻合较好，这也说明蒸发波导环境下雷达具有低空超视距探测能力，同时也说明基于PEM-SSFA的综合数值模式及雷达性能评估方法的准确性。From the comparison of the evaluation results of the maximum detection distance of the radar and the actual detection effect of the radar, the two are in good agreement, which also shows that the radar has low-altitude over-the-horizon detection capability in the evaporative waveguide environment, and also shows that the comprehensive numerical model based on PEM-SSFA and the accuracy of radar performance evaluation methods.

然而，在试验数据的处理过程中，使用了目标假设以及单一蒸发波导环境近似处理，这些假设与近似都与实际并不完全相符，如船舶目标反射截面积的假设，考虑超视距探测情况下，电磁波被限制在波导层内，此时电磁波照射只能照射到波导层高度以下船体上，这些特征必然引起超视距探测时船舶目标RCS的一些变化。另外，海上的蒸发波导环境具有一定的时空分布特征，这些必然为雷达性能评估带来一定的误差。However, in the process of processing the test data, the target assumption and the approximate processing of the single evaporation waveguide environment are used. These assumptions and approximations are not completely consistent with the actual situation. , the electromagnetic wave is limited in the waveguide layer, at this time, the electromagnetic wave irradiation can only irradiate the hull below the height of the waveguide layer, these characteristics will inevitably cause some changes in the RCS of the ship target during over-the-horizon detection. In addition, the evaporative duct environment at sea has certain temporal and spatial distribution characteristics, which will inevitably bring certain errors to radar performance evaluation.

以上所述，仅为本发明较佳的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，根据本发明的技术方案及其发明构思加以等同替换或改变，都应涵盖在本发明的保护范围之内。The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims

1. waveguide over-the-horizon radar has:

Measure the sensor unit of the hydrometeorological data that comprise sea table water temperature, sea atmospheric temperature, wind speed and atmospheric humidity at least;

According to the described environmental parameter that described sensor unit is gathered, calculate described atmospheric stability by calculating Richardson number Ri and Monin-Obukhov scale length L '; Under the state of different atmospheric stabilities, calculate the waveguide computing module of the Atmospheric corrections refractive index of sea evaporation waveguide height and sea evaporation waveguide;

According to sea evaporation waveguide height and the Atmospheric corrections refractive index of described waveguide computing module output, judge whether current radar has the over the horizon assessment mould module of over the horizon performance;

During work, described over the horizon evaluation module is according to described duct height and Atmospheric corrections refractive index, calculate the trapping frequency of current sea evaporation waveguide, when described trapping frequency during greater than the natural frequency of current radar, and duct height is higher than height of radar antenna, judges that current radar has the over the horizon performance.

2. a kind of waveguide over-the-horizon radar according to claim 1, be further characterized in that and have the radar range evaluation module: by the radar return power of more different transmission ranges and the minimum detectable signal power of radar: if at the radar return power of inner certain distance of the sea evaporation waveguide minimum detectable signal power greater than radar, then current distance is the detectable distance of radar.

3. a kind of waveguide over-the-horizon radar according to claim 1, be further characterized in that and have radargrammetry error evaluation module: whether receive the initial elevation angle that current sea evaporation waveguide height that described waveguide computing module draws and Atmospheric corrections refractive index judge current radar greater than zero, calculate the total length in multilayer waveguide space (comprising sea evaporation waveguide and space waveguide), propagated at the ray that radar antenna sends and the overall height in multilayer space according to ray theory, compare apart from the actual range of radar and the apparent height of target with target, obtain height error and the distance error of radargrammetry.

4. a kind of waveguide over-the-horizon radar according to claim 1, be further characterized in that: have adjustable for height radar antenna: the sea evaporation waveguide height and the current antenna height that calculate according to described waveguide computing module, rise or fall radar antenna, described radar wave is propagated in waveguide.

5. a kind of waveguide over-the-horizon radar according to claim 1, be further characterized in that: the radar antenna with changeable frequency, the trapping frequency of the current sea evaporation waveguide that calculates according to described over the horizon assessment mould module, adjustment to self frequency is carried out makes described radar frequency greater than the trapping frequency of current sea evaporation waveguide.

6. a kind of waveguide over-the-horizon radar according to claim 1, be further characterized in that: have the target identification module: calculate radar wave regularity of energy distribution in the evaporation waveguide pipe of sea by the radar emission power meter, for the over the horizon target, according to the energy of echo strength divided by this point of radar emission power in waveguide, just can judge the size of over the horizon target, target sizes can be divided into general objective, middle target and little target.

7. a kind of waveguide over-the-horizon radar according to claim 1 is further characterized in that: the computing formula that described waveguide computing module calculates Richardson number Ri is:

R_{i} = \frac{g}{T} \cdot \frac{&PartialD; θ / &PartialD; z}{{(&PartialD; u / &PartialD; z)}^{2}}

When 0＜Ri＜1, current atmosphere is in neutrality or steady state (SS), when Ri＜0, judges that current atmosphere plays pendulum;

The Monion-Obukhov length L ' computing formula be:

L^{'} = \frac{u^{*} &PartialD; u / &PartialD; T}{kg &PartialD; θ / &PartialD; T},

U wherein ^*Be friction velocity

u^{*} = \sqrt{\frac{τ}{ρ}},

τ is shearing stress;

Sea evaporation waveguide height for (0＜Ri＜1) under neutral and the stable atmospheric conditions:

Z^{*} = \frac{{ΔN}_{P}}{- 0.125 (\log_{e} (\frac{h_{1}}{h_{0}}) + \frac{5.2 h_{1}}{L^{'}}) - \frac{5.2 {ΔN}_{p}}{L^{'}}},

Wherein

L^{'} = \frac{u^{*} &PartialD; u / &PartialD; T}{kg &PartialD; θ / &PartialD; T}

Np is the potential index of refraction, h ₀Be sea level height, h ₀=0.00000015, h ₁Be sensor height;

Work as z ^*＜0 o'clock or

The time, then:

Z^{*} = \frac{{ΔN}_{P} (1 + 5.2) + 0.65 h_{1}}{- 0.125 \log_{e} (\frac{h_{1}}{h_{0}})}

For (R under the instability condition _i＜0 o'clock) sea evaporation waveguide height:

Z^{*} = \frac{1}{\sqrt[4]{φ^{4} - \frac{18}{L^{'}} φ^{3}}}

φ is flux profile function

Wherein

φ = \frac{- 0.125 B}{{ΔN}_{p}},

B = \log_{e} [\frac{h_{1}}{h_{0}}] - ψ

B is flux profile parameter, and ψ is flux profile function;

The Atmospheric corrections refractive index of evaporation waveguide is under stable or neutral atmosphere state

M (h) = M_{s} + \frac{h}{8} - [\frac{0.125 Z^{*}}{1 + \frac{5.2 Z^{*}}{L^{'}}}] [\log_{e} (\frac{h_{0} + h}{h_{0}}) - \frac{5.2 h}{L^{'}}]

Under the rough atmosphere state, the Atmospheric corrections of evaporation waveguide refraction ladder is

M (h) = M_{s} + \frac{h}{8} - [\frac{0.125 Z^{*}}{φ (\frac{Z^{*}}{L^{'}})}] [\log_{e} (\frac{h_{0} + h}{h_{0}}) - ψ (\frac{Z^{*}}{L^{'}})]

, wherein Ms is at h ₀The Atmospheric corrections refractive index of height can directly be measured.

8. a kind of waveguide over-the-horizon radar according to claim 7 is further characterized in that: described over the horizon assessment mould module is calculated the electromagnetic maximum wavelength of described sea evaporation waveguide trapping and is:

λ_{\max} = \frac{8 \sqrt{2} \times 10^{- 3}}{3} \cdot {&Integral;}_{z_{0}}^{d} \sqrt{M (z) - M (d)} dz

（m）

All the time d is sea evaporation waveguide height, is described Z ^*, z represents differing heights, M(z) is the Atmospheric corrections refractive index of differing heights, z ₀Be sea level height;

Calculating the electromagnetic low-limit frequency of described evaporation waveguide trapping is:

f_{\min} = \frac{c}{λ_{\max}} = \frac{79.49449}{{&Integral;}_{z_{0}}^{d} \sqrt{M (z) - M (d)} dz}

(GHz) in the formula, c is the light velocity (2.997925.10 ⁸M/s).

9. a kind of waveguide over-the-horizon radar according to claim 3, be further characterized in that: the method for work of described radar range evaluation module is as follows:

The target echo power that radar receives can be write as the form of one-way propagation loss:

P _r＝-8.55+10log ₁₀(P _tσf ²)+2G-L _s-L _a-2L _single

Receive theory according to radar, the minimum detectable signal power of radar is S _Imin, determined by the radar receiver performance,

S_{i \min} = {kT}_{0} B_{n} F_{0} D_{0} = {kT}_{0} B_{n} F_{0} {(\frac{S_{0}}{N_{0}})}_{\min}

K is Boltzmann constant, k=1.38 * 10 ^-23(J/K); T is resistance temperature, with absolute temperature (K) metering, for 17 ℃ of room temperatures, T=T ₀=290K; B _nBe the passband of equipment,

τ is pulse width; F ₀Be the noise figure of receiver,

Be the minimum signal to noise ratio (S/N ratio) of receiver output terminal;

When the power P that receives _rGreater than S _IminThe time, radar could be found target reliably, works as P _rJust in time equal S _IminThe time, just obtain the maximum operating range R of this target of detections of radar _Max, and P _rLess than S _IminThe time, target is in the radar electromagnetism blind area.

10. a kind of waveguide over-the-horizon radar according to claim 3, be further characterized in that: the method for work of described error-detecting module is as follows:

Use ray theory, set up the evaluation profile-raytrace pattern of radar range finding and altimetry error.

By Snell rule, α ₂Can obtain by following formula,

\cos α_{2} = [1 + (N_{1} - N_{2}) \times 10^{- 6} - \frac{dir \cdot dh}{r_{0} + h_{1}}] \cos α_{1}

Dir is directions of rays, when ray is upwards propagated, and dir=1, when ray is propagated downwards, dir=-1, Ψ ₁Be bending of a ray angle,

Ψ_{1} = \frac{2 (N_{1} - N_{2}) \times 10^{- 6}}{\tan α_{1} + \tan α_{2}}

β is geocentric angle, according to Abel, and et.al, 1982,

β ₁＝Ψ ₁+α ₂-α ₁

According to the cosine law, TRGAPP1 represents that ray in the length of this sheaf space, can be obtained by following formula

{TRG}_{APP!} = \sqrt{{(r_{0} + h_{1})}^{2} + {(r_{0} + h_{2})}^{2} - 2 (r_{0} + h_{1}) (r_{0} + h_{2}) \cos β_{1}}

Calculate TRGAPP1 and the β of each layer by iteration ₁, the result adds up with gained, can obtain the total length TRG that ray is propagated in the space _APPWith total geocentric angle β _Total

{TAG}_{APP} = Σ_{l = 1}^{L} {TRG}_{APPl}

β_{total} = Σ_{l = 1}^{L} β_{1}

Target is TRG apart from the actual range of radar, is obtained by following formula:

TRG = \sqrt{{(r_{0} + h_{REL})}^{2} + {(r_{0} + h_{n})}^{2} - 2 (r_{0} + h_{REL}) (r_{0} {+ h}_{n}) \cos β_{total}} \cdot

Then the distance error of target is:

TRGERR＝TRG _APP-TRG

The apparent height of target is THTAPP, uses 4/3 equivalent earth's radius, and actual ray is become approximate straight line, and gained target apparent height is:

{THT}_{APP} = \sqrt{{[4 / 3 (r_{0} + h_{REL})]}^{2} + {TRG}_{APP}^{2} - 2 [4 / 3 (r_{0} + h_{REL})] {TRG}_{APP} \cos α_{0}} - 4 / 3 (r_{0} + h_{n})

Can obtain the height error of target:

THTERR＝THT _APP-h _n

Utilize above-mentioned formula, the program that the available simulation ray that programs is propagated in the space is assessed the height and distance error of radargrammetry.