CN104101869A - Ground wave radar moving object simulation modeling method in polar coordinate - Google Patents

Abstract

The invention relates to a ground wave radar moving object simulation modeling method in a polar coordinate. The ground wave radar moving object simulation modeling method under a polar coordinate is used for analyzing, validating and evaluating the performance of methods of object track, integration and the like tracking. The method includes the steps of firstly, establishing a motion model corresponding to a uniform acceleration model in the polar coordinate with a radar station as a pole for an object to obtain actual motion parameters of the object at different time; secondly, introducing measurement errors of a ground wave radar system to correct the actual motion parameters obtained in the first step, and simulating to obtain observation motion parameters of the object; thirdly, introducing environmental clutter on the base of the observation motion parameters of the object in the second step, and simulating to obtain point trace data of the moving object.

Description

Ground wave radar moving target simulation modeling method under a kind of polar coordinates

Technical field

The present invention is applied to movement overseas targeted surveillance monitoring field, ground wave radar moving target simulation modeling method under a kind of polar coordinates has been proposed, the method can be simulated and generate the target data that ground wave radar is measured, and can be used for the Study and estimate of the methods such as Track In Track, fusion.

Background technology

High-frequency ground wave radar radiothermy (3～30MHz) is in the conduction ocean surface diffraction propagation little feature that decays, adopt vertical polarized antenna radiation electric wave, the following moving targets such as naval vessel, aircraft, iceberg and guided missile that occur of energy over-the-horizon detection sea level sight line, more than operating distance can reach 300km.Simultaneously, high-frequency ground wave radar utilizes ocean surface to the single order scattering of frequency electromagnetic waves and second order dispersion mechanism, can from radar return, extract the sea situation information such as wind field, Lang Chang, flow field, realize to marine environment on a large scale, high precision and round-the-clock Real-Time Monitoring.

Radiowave is during towards emission of sea surface, in seawater surface, can there is a kind of electromagnetic wave propagation model, be called earthwave (Ground Wave), be a kind of surface wave (Surface Wave), so high-frequency ground wave radar is also called high frequency surface wave radar (HF Surface Wave Radar).Propagation of ground wave decay in medium wave and short-wave band seawater surface is very little, and earthwave to a certain extent can be along crooked earth surface propagation, and the following far place of arrival point horizontal line, realizes over-the-horizon propagation.Therefore utilize high-frequency ground wave radar that earthwave over-the-horizon propagation characteristic surveys also referred to as earthwave over-the-horizon radar (Over-The-Horizon Radar), detection range difference can reach 200～500km conventionally according to emissive power and frequency.The over-the-horizon radar of other two types is respectively sky-wave OTH radar and the microwave radar that utilizes atmospheric duct feature, the former realizes the detection to the outer targets of thousands of kilometer by ionosphere to the reflection of high frequency radio wave, and the latter can survey the target outside 100 kilometers.

Chinese patent CN101206260 discloses the disposal route of radar target information in navigating tube automatization system, this patent is mainly the processing accuracy that solves Target Tracking System, utilize the conversion between air traffic control radar polar coordinates (distance, orientation, highly) report and processing planimetric rectangular coordinates, reduce the error of calculation of common transfer algorithm.

Chinese patent CN102508238 discloses a kind of radar tracking method based on Rotating Transition of Coordinate, it is based on stochastic variable related coefficient and Rotating Transition of Coordinate principle, to reach on the basis of nonlinear degree of the measurement equation in quantitative measurement radar filtering system model, reduce the measurement equation nonlinear degree in radar filtering system model, thereby improve radar tracking effect.

But all relating to, above-mentioned technology how the movement overseas target of earthwave radar detection is not set up to corresponding realistic model, to the methods such as Track In Track, fusion are analyzed, evaluated.

Summary of the invention

Object of the present invention is exactly the problem that at present Moving Target Exploitation in earthwave Radar Sea is lacked the platform of simulation modeling for solving, by the ground wave radar moving target simulation modeling method under polar coordinates, thereby the performance of the methods such as targetpath tracking, fusion is analyzed, verified with evaluation foundation is provided.

For achieving the above object, the present invention adopts following technical scheme:

A ground wave radar moving target simulation modeling method under polar coordinates, its detailed process is:

Step 1, sets up the corresponding motion model of even acceleration model take under the polar coordinates that radar station is limit to target, obtain not the real motion parameter of target in the same time;

Step 2, the real motion parameter that the measuring error of introducing ground wave radar system obtains step 1 is revised, and emulation obtains target observation kinematic parameter;

Step 3, introduces environment clutter on the target observation kinematic parameter basis obtaining in step 2, and emulation obtains moving target point mark data.

In described step 1, under polar coordinates, the motion model of target is as follows:

$\left\{\begin{array}{c}{r}_t=\sqrt{r_0^2+{(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)}^2+2r_0(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)\cos \mathrm{\α}}\\ {\mathrm{\θ}}_t=\mathrm{\Φ}-\mathrm{arc}\sin (r_0\sin (\mathrm{\Φ}-{\mathrm{\θ}}_0)/r_t)\\ v_{\mathrm{rt}}=(v_0+\mathrm{at})\cos \left(\mathrm{arc}\sin (r_0\sin (\mathrm{\Φ}-{\mathrm{\θ}}_0)/r_t)\right)\end{array}\right.$

Wherein, r _tfor the radial distance between t moment target location and radar station; r ₀for the radial distance between initial time target location and radar station; Motion constantly t is usingd the sweep spacing of radar as base unit; A is acceleration; α represents the angle between initial time target travel direction and target radial speed direction; θ _tfor t constantly target location vector and radar method to angle; Ф be target travel direction and radar method to angle ,-π≤Ф≤π; θ ₀for target initial orientation angle; v ₀for target initial velocity; v _rtradial velocity for t moment target; Target travel direction and target radial speed angular separation are β=arcsin (r ₀sin (π-Φ+θ ₀)/r _t), corresponding β is 0 ° of < β <90 ° of acute angle; Target travel direction and target radial speed angular separation are β=π-arcsin (r ₀sin (π-Φ+θ ₀)/r _t), corresponding β is 90 °, obtuse angle < β <180 °;

According to target in radar method to the right or left side motion, according to β angle, be acute angle or obtuse angle simultaneously, determine the condition that motion model is carried out to corresponding correction:

During >0 ° of (1) 90 ° of > Φ,

During >90 ° of (2) 180 ° of > Φ, critical angle δ=Φ-90 ° >0, works as θ ₀during < δ,

(3), during >-180 ° of-90 ° of > Φ, critical angle δ=Φ+90 ° <0, works as θ ₀during > δ,

(4) 0> Φ >-90 ° time,

In above-mentioned four kinds of situations, when β is acute angle, modus ponens β=arcsin (r ₀sin (π-Φ+θ ₀)/r _t) expression-form, when β is obtuse angle, modus ponens β=π-arcsin (r ₀sin (π-Φ+θ ₀)/r _t) expression-form, described motion model is revised.

In described step 2, suppose the observation noise Gaussian distributed of earthwave radar measurement, the target component observing is expressed as:

$\left\{\begin{array}{c}{r}_{\mathrm{observe}}=r_{\mathrm{orignal}}+{\mathrm{\&sigma;}}_{r}n\\ v_{\mathrm{observe}}=v_{\mathrm{original}}+{{\mathrm{\&sigma;}}_v}^{}n\\ {\mathrm{\&theta;}}_{\mathrm{observe}}={\mathrm{\&theta;}}_{\mathrm{original}}+{\mathrm{\&sigma;}}_{\mathrm{\&theta;}}n\end{array}\right.$

Wherein, r _observe, v _observe, θ _observerepresent respectively radial distance, radial velocity and azimuthal observed reading, r _original, v _original, θ _originalthe actual value that represents respectively three, σ _r, σ _v, σ _θthe standard deviation that represents respectively radial distance, radial velocity and azimuth measurement error, n represents that average is zero, variance is 1 normally distributed random variable, by adjusting measuring error standard extent, the disturbance of change to each measurement parameter, obtains the observed reading of the ground wave radar detection of a target under polar coordinates.

In described step 3, the preparation method of moving target point mark data is:

On a certain moment observation moving target data basis obtaining in step 2, within the scope of target detection, add the clutter point of some.Wherein, the number of clutter point is obeyed Poisson distribution, and the average of Poisson distribution determines by the product of clutter number in the detection area of radar and unit area, and the clutter number in unit area (being noise intensity) can be set according to actual needs; The kinematic parameter of clutter point generates at random.

The present invention, in order to study better the methods such as the tracking of ground wave radar targetpath, fusion, verifies its validity, has proposed the ground wave radar moving target simulation modeling method under a kind of polar coordinates, has following characteristics:

(1) can directly generate the Targets Dots under polar coordinates, the error of having avoided coordinate conversion and having introduced thus, practical;

(2) can emulation plurality of target forms of motion, above-described embodiment be take uniformly accelrated rectilinear motion as example, with other motion model or after model combination replaces, can obtain multi-form target travel result, as target maneuver etc.;

(3) observation noise, environment clutter add the feature that has taken into full account ground wave radar target detection, make the target of emulation more approach real ground wave radar result of detection;

(4) observation noise and environment noise intensity can be changed flexibly, with the target detection result under emulation varying environment.

Accompanying drawing explanation

The Track In Track flow process of Fig. 1 based on the modeling of ground wave radar moving target simulation;

The motion model (direction of motion and radar method to acutangulate) of Fig. 2 target under polar coordinates;

The motion model of Fig. 3 target under polar coordinates (direction of motion with radar method to becoming obtuse angle);

Five moving target real motion track emulation results of Fig. 4 a;

The partial enlarged drawing of Fig. 4 b Fig. 4 a;

Five moving target observed reading simulation results of Fig. 5 a;

The partial enlarged drawing of Fig. 5 b Fig. 5 a;

The simulation result of Fig. 6 target 1;

Fig. 7 target velocity change curve;

The moving target simulation result that Fig. 8 a comprises clutter;

The partial enlarged drawing of Fig. 8 b Fig. 8 a;

Fig. 9 clutter point and impact point simulation result;

Figure 10 targetpath tracking results example.

Embodiment

Below in conjunction with accompanying drawing and embodiment, the present invention will be further described.

Track In Track treatment scheme based on ground wave radar moving target simulation data as shown in Figure 1.Wherein, in dashed rectangle, be depicted as moving target simulation flow process (dotted line frame is not emulation modelling method of the present invention, conventionally can adopt existing techniques in realizing, repeats no more) outward.Give the initial motion parameter (position, speed etc.) that sets the goal, utilize motion model (linear uniform motion, uniformly accelrated rectilinear motion, motor-driven model etc.) can obtain target in real motion parameter in the same time not; Consider the measuring error of ground wave radar system, in target real motion parameter, add corresponding measuring error, can emulation obtain the kinematic parameter of target observation; On the basis of target observation kinematic parameter, introduce environment clutter, just can obtain simulation objectives point mark.The moving target point mark data of utilizing emulation to obtain, utilize Track In Track Processing Algorithm to process the flight path that can obtain target.The movement locus of the targetpath obtaining and real goal is contrasted, can provide foundation for analysis, the evaluation of Track In Track algorithm performance.

Generally, the motion state of movement overseas target does not have too large motor-driven situation, therefore, conventionally its motion model is assumed to linear uniform motion.In order to reflect that more accurately less motor-driven situation may appear in moving target, the even acceleration model (Constant Acceleration, CA) of take carries out the derivation of target state as example.

Figure 2 shows that the motion schematic diagram of a moving target under polar coordinates.The original state of hypothetical target is: radial distance r ₀, azimuth angle theta ₀, speed v ₀, acceleration a, along with radar method to becoming Φ (π≤Φ≤π) angle to do uniformly accelrated rectilinear motion.

In Fig. 2, θ _tfor t constantly target location vector and radar method to angle, r _tfor the radial distance between t moment target location and radar station, v _tfor the true velocity of t moment target, v _rtradial velocity for t moment target.Wherein, t is usingd the sweep spacing of radar as base unit.

As shown in Figure 2,

α＝Φ-θ ₀，ω＝π-α＝π-(Φ-θ ₀) (1)

α represents the angle between initial time target travel direction and target radial speed direction.

By the cosine law, can try to achieve r _t,

$\begin{array}{c}{r}_t=\sqrt{r_0^2+{(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)}^2-{2r}_0(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)\cos \mathrm{\&omega;}}\\ =\sqrt{r_0^2+{(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)}^2-{2r}_0(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)\cos (\mathrm{\&pi;}-(\mathrm{\&Phi;}-{\mathrm{\&theta;}}_0))}\\ =\sqrt{r_0^2+{(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)}^2+{2r}_0(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)\cos (\mathrm{\&Phi;}-{\mathrm{\&theta;}}_0)}\end{array}---\left(2\right)$

Wherein, t=(n-1) T, T is integration time, n is scanning times, n=1,2,3 ..., n is natural number.

Easily know θ _t=Φ-β.By sine, can try to achieve β:

$\frac{r_t}{\sin \mathrm{\&omega;}}=\frac{r_0}{\sin \mathrm{\&beta;}}---\left(3\right)$

Meanwhile, can obtain v _rt,

v _rt＝v _tcosβ＝(v ₀+at)cosβ (5)

$\begin{array}{c}{v}_{\mathrm{rt}}=(v_0+\mathrm{at})\cos \left(\mathrm{arc}\sin (r_0\sin (\mathrm{\&pi;}-\mathrm{\&Phi;}+{\mathrm{\&theta;}}_0)/r_t)\right)\\ =(v_0+\mathrm{at})\cos \left(\mathrm{arc}\sin (r_0\sin (\mathrm{\&Phi;}-{\mathrm{\&theta;}}_0)/r_t)\right)\end{array}---\left(6\right)$

Thus, show that under polar coordinates, the motion model of target is as follows:

$\left\{\begin{array}{c}{r}_t=\sqrt{r_0^2+{(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)}^2+2r_0(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)\cos \mathrm{\&alpha;}}\\ {\mathrm{\&theta;}}_t=\mathrm{\&Phi;}-\mathrm{arc}\sin (r_0\sin (\mathrm{\&Phi;}-{\mathrm{\&theta;}}_0)/r_t)\\ v_{\mathrm{rt}}=(v_0+\mathrm{at})\cos \left(\mathrm{arc}\sin (r_0\sin (\mathrm{\&Phi;}-{\mathrm{\&theta;}}_0)/r_t)\right)\end{array}\right.---\left(7\right)$

In above model process of establishing, because the calculating of angle relates to arcsin function, choosing of angle value need to divide different situations to discuss.

The field of definition of arcsin function is [1 ,+1], and codomain is [0, pi/2], therefore, in above-mentioned model inference process according to formula β=arcsin (r ₀sin (π-Φ+θ ₀)/r _t) carry out value be corresponding β be the situation of acute angle (0 ° of < β <90 °).

When β is obtuse angle (90 ° of < β <180 °), its value should be

β＝π-arcsin(r ₀sin(π-Φ+θ ₀)/r _t) (8)

When Fig. 3 is >90 ° of 180 ° of > Φ, situation when β is obtuse angle, now,

β＝π-arc sin(r(0)sin(π-Φ+θ(0))/r(t)) (9)

In like manner, when target is when radar method is moved to the left, also should consider in two kinds of situation.

By above analysis, obtain following four kinds of situations (its schematic diagram is identical with Fig. 3 principle with Fig. 2, no longer draws at this):

During >0 ° of (1) 90 ° of > Φ,

During >90 ° of (2) 180 ° of > Φ, critical angle δ=Φ-90 ° >0 °, works as θ ₀during < δ,

(3), during >-180 ° of-90 ° of > Φ, critical angle δ=Φ+90 ° <0 °, works as θ ₀during > δ,

During >-90 ° of (4) 0 ° of > Φ,

In above-mentioned four kinds of situations, when β is acute angle, the expression-form of modus ponens (3), when β is obtuse angle, the expression-form of modus ponens (8).By above model, just can obtain the dreamboat simulation result under different motion situation.

In order to simulate more truly the measurement of ground wave radar, need to consider the observation noise of radar system.In realistic model, suppose the observation noise Gaussian distributed of earthwave radar measurement, the target component observing can be expressed as:

$\left\{\begin{array}{c}{r}_{\mathrm{observe}}=r_{\mathrm{orignal}}+{\mathrm{\&sigma;}}_{r}n\\ v_{\mathrm{observe}}=v_{\mathrm{original}}+{{\mathrm{\&sigma;}}_v}^{}n\\ {\mathrm{\&theta;}}_{\mathrm{observe}}={\mathrm{\&theta;}}_{\mathrm{original}}+{\mathrm{\&sigma;}}_{\mathrm{\&theta;}}n\end{array}\right.---\left(10\right)$

Wherein, r _observe, v _observe, θ _observerepresent respectively radial distance, radial velocity and azimuthal observed reading, r _original, v _original, θ _originalthe actual value that represents respectively three, σ _r, σ _v, σ _θthe standard deviation that represents respectively radial distance, radial velocity and azimuth measurement error, n represents that average is zero, the normally distributed random variable that variance is 1.By adjusting measuring error standard extent, can change the disturbance to each measurement parameter.

By (10) formula, can be obtained the observed reading of the ground wave radar detection of a target under polar coordinates.

2, emulation experiment

(1) real goal emulation

In order to verify the correctness of the moving target analogy method of proposition, respectively 5 targets with different motion parameter are carried out to emulation.The direction of motion of 5 targets and radar method to angle Φ be respectively 0 °, 90 °, 10 °, 120 ° ,-150 °, respectively along radar method to, to vertical direction, radar normal axis clockwise direction, radar normal axis, counterclockwise move with radar method, utilize the target movement model of setting up to carry out moving target simulation, result is as shown in Fig. 4 a, 4b.

(2) observed object emulation

For ground wave radar that is virtually reality like reality measures, when producing target observation value, take into full account the measuring error of radar system.The feature measuring in conjunction with earthwave radar target and known to the statistical study of a large amount of actual measurement ground wave radar data, its velocity survey precision is the highest, and measuring error is 0.02m/s left and right; Radial distance precision is taken second place, and measuring error is 3km left and right; Azimuth accuracy is minimum, and measuring error is 3 ° of left and right.The statistical value of reference measure error, the measuring noise square difference of setting different motion target component.

On the basis of real goal, measurement noise is taken into account, obtain target observation result as shown in Fig. 5 a, 5b.

For the motion state of display-object more clearly, the motion state of target 1 is shown as shown in Figure 6 separately.

Fig. 7 has provided the speed change curves of target, from known this target of change curve of speed actual value, is to do uniformly accelerated motion, matches with the even acceleration model of setting up.Speed measuring value fluctuates near actual value, on overall trend, can think the uniformly accelerated motion with noise.

(3) target simulator in clutter environment

Clutter in high-frequency ground wave radar target detection result is counted and obey Poisson distribution in each scanning.If equally distributed clutter density is λ/km ², can obtain equally distributed number of echoes in investigative range.

The clutter of emulation and Targets Dots distribute as shown in Fig. 8 a, 8b.

For the motion state of display-object more clearly, the motion state of the target that comprises clutter point 1 is presented in Fig. 9 separately.

(4) Track In Track result

Utilize the realistic model of setting up to obtain the actual value of target and the simulation result of measuring value, this simulation result is applied to, in Track In Track experiment, obtain an embodiment.Figure 10 is the tracking results of utilizing the target 1 that Track In Track algorithm obtains.Can carry out Track In Track experiment for different targets.

Claims (4)

1. the ground wave radar moving target simulation modeling method under polar coordinates, is characterized in that, its detailed process is:

Step 1, sets up the corresponding motion model of even acceleration model take under the polar coordinates that radar station is limit to target, obtain not the real motion parameter of target in the same time;

Step 2, the real motion parameter that the measuring error of introducing ground wave radar system obtains step 1 is revised, and emulation obtains target observation kinematic parameter;

Step 3 is introduced environment clutter on the target observation kinematic parameter basis of step 2, and emulation obtains moving target point mark data.

2. the ground wave radar moving target simulation modeling method under polar coordinates as claimed in claim 1, is characterized in that, in described step 1, under polar coordinates, the motion model of target is as follows:

$\left\{\begin{array}{c}{r}_t=\sqrt{r_0^2+{(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)}^2+2r_0(v_{0}t+\frac{1}{2}{\mathrm{at}}^2)\cos \mathrm{\&alpha;}}\\ {\mathrm{\&theta;}}_t=\mathrm{\&Phi;}-\mathrm{arc}\sin (r_0\sin (\mathrm{\&Phi;}-{\mathrm{\&theta;}}_0)/r_t)\\ v_{\mathrm{rt}}=(v_0+\mathrm{at})\cos \left(\mathrm{arc}\sin (r_0\sin (\mathrm{\&Phi;}-{\mathrm{\&theta;}}_0)/r_t)\right)\end{array}\right.$

Wherein, r _tfor the radial distance between t moment target location and radar station; r ₀radial distance for initial time and radar station; T moves constantly, usings the sweep spacing of radar as base unit; A is acceleration; α represents the angle between initial time target travel direction and target radial speed direction; θ _tfor t constantly target location vector and radar method to angle; Ф be target travel direction and radar method to angle ,-π≤Ф≤π; Initial orientation angle θ ₀; Initial velocity v ₀; v _rtradial velocity for t moment target; Target travel direction and target radial speed angular separation are β=arcsin (r ₀sin (π-Φ+θ ₀)/r _t), corresponding β is 0 ° of < β <90 ° of acute angle; Target travel direction and target radial speed angular separation are β=π-arcsin (r ₀sin (π-Φ+θ ₀)/r _t), corresponding β is 90 °, obtuse angle < β <180 °;

According to target in radar method to the right or left side motion, according to β angle, be acute angle or obtuse angle simultaneously, determine the condition that motion model is carried out to corresponding correction,

During >0 ° of (1) 90 ° of > Φ,

During >90 ° of (2) 180 ° of > Φ, critical angle δ=Φ-90 ° >0 °, works as θ ₀during < δ,

(3), during >-180 ° of-90 ° of > Φ, critical angle δ=Φ+90 ° <0 °, works as θ ₀during > δ,

During >-90 ° of (4) 0 ° of > Φ,

In above-mentioned four kinds of situations, when β is acute angle, modus ponens β=arcsin (r ₀sin (π-Φ+θ ₀)/r _t) expression-form, when β is obtuse angle, modus ponens β=π-arcsin (r ₀sin (π-Φ+θ ₀)/r _t) expression-form, described motion model is revised.

3. the ground wave radar moving target simulation modeling method under polar coordinates as claimed in claim 1, is characterized in that, in described step 2, supposes the observation noise Gaussian distributed of earthwave radar measurement, and the target component observing is expressed as:

$\left\{\begin{array}{c}{r}_{\mathrm{observe}}=r_{\mathrm{orignal}}+{\mathrm{\&sigma;}}_{r}n\\ v_{\mathrm{observe}}=v_{\mathrm{original}}+{{\mathrm{\&sigma;}}_v}^{}n\\ {\mathrm{\&theta;}}_{\mathrm{observe}}={\mathrm{\&theta;}}_{\mathrm{original}}+{\mathrm{\&sigma;}}_{\mathrm{\&theta;}}n\end{array}\right.$

Wherein, r _observe, v _observe, θ _observerepresent respectively radial distance, radial velocity and azimuthal observed reading, r _original, v _original, θ _originalthe actual value that represents respectively three, σ _r, σ _v, σ _θthe standard deviation that represents respectively radial distance, radial velocity and azimuth measurement error, n represents that average is zero, variance is 1 normally distributed random variable, by adjusting measuring error standard extent, the disturbance of change to each measurement parameter, obtains the observed reading of the ground wave radar detection of a target under polar coordinates.

4. the ground wave radar moving target simulation modeling method under polar coordinates as claimed in claim 1, is characterized in that, in described step 3, the preparation method of moving target point mark data is:

On a certain moment observation moving target data basis obtaining in step 2, within the scope of target detection, add the clutter point of some; Wherein, the number of clutter point is obeyed Poisson distribution, and the average of Poisson distribution determines by the product of clutter number in the detection area of radar and unit area, and the clutter number in unit area is that noise intensity is set according to actual needs; The kinematic parameter of clutter point generates at random.