阅读说明：本技术 基于单观察哨数字望远镜的运动目标航迹获取方法 (Moving target track acquisition method based on single observation whistle digital telescope ) 是由 张敬卓 陈杰生 季军亮 于 2019-11-04 设计创作，主要内容包括：本发明提供了一种基于单观察哨数字望远镜的运动目标航迹获取方法,解决低空超低空近程机动目标的定位问题,以弥补低空雷达探测盲区。“观察哨”手持数字望远镜录取原始空情,原始空情仅包含方位角、高低角两坐标信息,且信息数据存在较大误差。本发明方法建立了目标运动数学模型,并利用非线性函数拟合算法估计目标角度变化参数,在目标运动规律基础上,估计目标真实方位角和高低角,进一步对目标距离进行估计,从而获得目标航迹。本发明适用于地面观察哨空情系统,为地面雷达提供目标指示。(The invention provides a moving target track acquisition method based on a single observation whistle digital telescope, which solves the positioning problem of a low-altitude ultra-low-altitude short-range maneuvering target so as to make up a low-altitude radar detection blind area. The handheld digital telescope of the observation whistle is used for recording original air conditions, the original air conditions only comprise azimuth angle and elevation angle coordinate information, and larger errors exist in information data. The method establishes a target motion mathematical model, estimates target angle change parameters by using a nonlinear function fitting algorithm, estimates the real azimuth angle and the elevation angle of the target on the basis of the target motion rule, and further estimates the target distance so as to obtain the target track. The invention is suitable for a ground sentry air condition observation system and provides target indication for a ground radar.)

1. The moving target track acquisition method based on the single observation whistle digital telescope is characterized by being suitable for a non-small-route shortcut target and comprising the following steps of:

step 1) continuously tracking a moving target by using a digital telescope, acquiring observation data and transmitting the observation data to a command information center platform end; the observation data comprises real-time azimuth angle theta and elevation angle of the moving target

Step 2) establishing an angle information change rule of the moving target based on the observation data:

the change rule of the azimuth angle is as follows:

θ＝arctan[a(t-t_x)]+θ_x

the change rule of the high and low angles is as follows:

in the formula:

t is the time variable observed for a moving object, { a, t_x,θ_xThe azimuth angle change rule parameter of the target is adopted, and the motion state of the target is assumed to be kept unchanged when observing whistle pair null observation, { a, t_x,θ_xThe three parameters are constants; wherein a is v/r_xV is the velocity of the target, r_xA target airway shortcut is taken; t is t_xIs the time theta corresponding to the flying time of the target to the short-cut of the air route_xThe azimuth angle parameter corresponding to the target route shortcut is obtained;

{a,b,t_xthe elevation angle change rule parameters of the target are used as the elevation angle change rule parameters; wherein, b is h/r_xH is the height of the target;

step 3) solving the azimuth angle change rule parameters and the elevation angle change rule parameters of the moving target:

observing a time sequence of angle data of the moving target based on an observation whistle digital telescope, estimating azimuth angle change rule parameters { a, t) of the target according to the angle information change rule in the step 2) and by utilizing a Levenberg-Marquardt algorithm_x,θ_xAnd elevation angle change law parameter { a, b, t }_x}；

Step 4) obtaining the azimuth angle change rule parameters { a, t) of the target obtained in the step 3)_x,θ_xAnd elevation angle change law parameter { a, b, t }_xSubstituting the azimuth angle of the moving target into a corresponding angle change rule formula in the step 2), and calculating an estimated value of the azimuth angle of the moving target at the moment tAnd the estimated value of the elevation angle at the time t

And 5) calculating the slant distance R of the moving target relative to the digital telescope according to the angle estimation result in the step 4):

in the formula:

v₀is the estimated velocity of the moving object;

step 6) using 5-10 latest time sampling observation data as input, and iteratively estimating the distance of the moving target according to steps 3), 4) and 5) to obtain a moving target slope distance time sequence R ═ R₁,R₂,…,R_nDetermine the track of the moving object

2. the method for acquiring the moving target track based on the single observation whistle digital telescope according to the claim 1, characterized in that, between the steps 1) -2), the observation data acquired by the digital telescope is preprocessed, specifically as follows:

A. removing repeated data in the observation data, and interpolating:

will t₁The observed data of the time are recorded as

B. rejecting excessively deviated data in the observed data, and interpolating:

b1, continuously observing any moving target for multiple times by using a digital telescope to obtain corresponding observation data;

b2, calculating the deviation variance between the observation data and the azimuth angle and elevation angle estimated value of the moving target respectively for the observation data obtained by each continuous observation

b3, calculating the average value of the variance of the deviation of all the observation angle data obtained in the step B2 and the angle estimation value of the moving targetAnd

b4, respectively enabling the azimuth angle and the elevation angle corresponding to each moment in the observation data in the step 1) to be respectively equal to the standard deviation average value obtained in the step B3

3. The method for acquiring the track of a moving object based on a single-observation whistle digital telescope as claimed in claim 2, wherein in step B2, the variance of the deviation of the observation data from the azimuth and elevation estimation values of the moving object is calculated according to the following formula:

wherein:

is t_iAn azimuthal observation of the time;

is t_iA time elevation angle observation value;

4. The method for acquiring the track of the moving target based on the single observation whistle digital telescope as claimed in claim 1, wherein the azimuth angle variation law parameter { a, t) of the target in the step 2)_x,θ_xAnd elevation angle change law parameter { a, b, t }_xThe specific estimation method comprises the following steps:

first, a function e is constructed_θAnd

wherein:

theta (t) is a specific parameter optimal azimuth angle change rule function to be searched and solved; theta is an observed value of the azimuth angle of the moving target;

Technical Field

The invention relates to a moving target track acquisition method based on a single observation whistle digital telescope, which belongs to the field of low-altitude target detection, solves the positioning problem of low-altitude and ultra-low-altitude short-range maneuvering targets, makes up the detection blind area of a low-altitude radar, is suitable for a ground observation whistle-sky-situation system, and provides target indication for a ground radar.

Background

The low-altitude target detection is mainly dominated by high-end products with complex technologies, such as low-altitude radars, photoelectric composite detection equipment and the like. The product has the prominent problems of high price, complex technology, limited use and popularization and the like. Due to the limitation of various factors such as electromagnetic interference, earth curvature and complex terrain, the ground-based radar has a short discovery distance to low-altitude targets, and a firepower unit cannot effectively respond to the low-altitude targets in a short time. For low-altitude and ultra-low-altitude anti-air-attack targets, the ground-based radar basically cannot complete air condition guarantee, and the contradiction is more acute for targets with stealth characteristics and interference characteristics or environments in mountain jungle regions. The laser ranging measurement distance is limited, the returned laser signal is weak due to the diffuse reflection effect of the surface of the target, usually only targets within 3000 meters are supported, and for maneuvering targets, the problem of poor ranging stability exists, and the distance parameter cannot be continuously recorded.

At present, the available digital telescope of novel ground "observation whistle" and wireless network can survey the sky information such as azimuth, high-low angle of target in real time to report to command information center platform end, but its original data precision of admission is low, the shake is big, non-steady, lacks target distance information moreover, fixes a position the target and obtains the track and awaits a urgent solution.

Disclosure of Invention

The invention provides a moving target track acquisition method based on a single observation whistle digital telescope, and aims to solve the technical problems that the accuracy of the original data of the empty information acquired by the digital telescope on the ground is low, the jitter is large, the data are not stable, and the target distance information is lacked, so that the moving target track cannot be acquired.

The invention conception of the invention is as follows:

assuming that the air moving target keeps horizontal uniform linear motion in a short time, establishing a ground rectangular coordinate, as shown in fig. 1; in the figure, the point O is the origin of coordinates and is the position where the whistle is observed; the Ox points to the positive north direction in a horizontal plane passing through the origin point to be positive; oy is vertical to the horizontal plane, and the upward pointing direction is positive, so that the height of the moving target is represented; oz is perpendicular to Ox and Oy and points to the right east as positive according to the right hand rule.

In fig. 1, an included angle between a connecting line between the horizontal projection of the target and the digital telescope and the due north direction is an azimuth angle, and is marked as θ; the included angle between the horizontal plane and the line between the target and the digital telescope is recorded as the elevation angle

Azimuth angle theta and elevation angle

The data can be acquired by using a digital electronic telescope and are all known data, and the azimuth time sequence of the acquired observation data is recorded as theta ═ theta₁,θ₂,…,θ_nAnd the high and low angle time series are recorded as

The target slant distance R is an unknown parameter and is a target parameter for the key solution of the invention, and if the solution obtains the distance information R of the target observed at the corresponding moment, the slant distance R of the target is determined to be { R ═ R-₁,R₂,…,R_n}. In order to improve the track quality, the motion rules of the azimuth angle and the elevation angle of the target are deduced, the information of the target angle is estimated according to the observation data, the true value is replaced by the estimated value, and the target track is finally obtained

The technical scheme of the invention is as follows:

the moving target track acquisition method based on the single observation whistle digital telescope is characterized by being applicable to non-small-route shortcut targets and comprising the following steps of:

step 1) continuously tracking a moving target by using a digital telescope, acquiring observation data and transmitting the observation data to a command information center platform end; the observation data comprises real-time azimuth angle theta and elevation angle of the moving target

Step 2) establishing an angle information change rule of the moving target based on the observation data:

the change rule of the azimuth angle is as follows:

θ＝arctan[a(t-t_x)]+θ_x

the change rule of the high and low angles is as follows:

in the formula:

t is the time variable observed for a moving object, { a, t_x,θ_xThe azimuth angle change rule parameter of the target is used as the { a, t } time when the observation whistle is empty, and the target motion state is assumed to be unchanged in a short time_x,θ_xThe three parameters are constants; wherein a is v/r_xV is the velocity of the target, r_xA target airway shortcut is taken; t is t_xIs the time theta corresponding to the flying time of the target to the short-cut of the air route_xThe azimuth angle parameter corresponding to the target route shortcut is obtained;

{a,b,t_xthe elevation angle change rule parameters of the target are used as the elevation angle change rule parameters; wherein, b is h/r_xH is the height of the target;

step 3) solving the azimuth angle change rule parameters and the elevation angle change rule parameters of the moving target:

observing a time sequence of angle data of the moving target based on an observation whistle digital telescope, estimating azimuth angle change rule parameters { a, t) of the target according to the angle information change rule in the step 2) and by utilizing a Levenberg-Marquardt algorithm_x,θ_xAnd elevation angle change law parameter { a, b, t }_x}；

Step 4) obtaining the azimuth angle change rule parameters { a, t) of the target obtained in the step 3)_x,θ_xAnd elevation angle change law parameter { a, b, t }_xSubstituting the azimuth angle of the moving target into a corresponding angle change rule formula in the step 2), and calculating an estimated value of the azimuth angle of the moving target at the moment t

And the estimated value of the elevation angle at the time t

And 5) calculating the slant distance R of the moving target relative to the digital telescope according to the angle estimation result in the step 4):

in the formula:

v₀is the estimated velocity of the moving object;

step 6) using 5-10 latest time sampling observation data as input, and iteratively estimating the distance of the moving target according to steps 3), 4) and 5) to obtain a moving target slope distance time sequence R ═ R₁,R₂,…,R_nDetermine the track of the moving object

Wherein the content of the first and second substances,

further, between the steps 1) -2), the observation data acquired by the digital telescope is preprocessed, specifically as follows:

A. removing repeated data in the observation data, and interpolating:

will t₁The observed data of the time are recorded as

t₂The observed data of the time are recorded as

The observed data of the time are recorded as

If t_iTime and t_jTime of day, theta_i＝θ_j，

Then order

The i ≠ j, i ≠ 1,2, … n, j ≠ 1,2, … n;

B. rejecting excessively deviated data in the observed data, and interpolating:

b1, continuously observing any moving target for multiple times by using a digital telescope to obtain corresponding observation data;

b2, calculating the deviation variance between the observation data and the azimuth angle and elevation angle estimated value of the moving target respectively for the observation data obtained by each continuous observation

And

b3, calculating the average value of the variance of the deviation of all the observation angle data obtained in the step B2 and the angle estimation value of the moving target

And

the mean value of standard deviation is obtained by evolution

And

b4, respectively enabling the azimuth angle and the elevation angle corresponding to each moment in the observation data in the step 1) to be respectively equal to the standard deviation average value obtained in the step B3

Andmaking a comparison, if a certain time t_kCorresponding azimuth angle theta_kDeviation from its estimated value by a value equal to or greater than the mean of the standard deviations

3-5 times of the azimuth angle theta_kIf the deviation is too large, let

If a certain time t_gCorresponding high and low angles

Deviation from its estimated value by a value equal to or greater than the mean of the standard deviations

3-5 times of the angle of elevation, representing the elevation angleIf the deviation is too large, let

Further, in step B2, the variance of the deviation of the observation data from the azimuth and elevation estimation values of the moving object is calculated according to the following formula:

wherein:

is t_iAn azimuthal observation of the time;

is t_iA time azimuth angle estimation value;

is t_iA time elevation angle observation value;

is t_iThe elevation angle estimate of the time.

Further, the azimuth angle change rule parameters { a, t) of the target in the step 2)_x,θ_xAnd elevation angle change law parameter { a, b, t }_xThe specific estimation method comprises the following steps:

first, a function e is constructed_θAnd

then search through the known azimuth and elevation observation data using Levenberg-Marquardt algorithm such that function e_θAnd

minimized parameter set { a, t_x,θ_xAnd { a, b, t }_xObtaining a motion rule parameter of the moving target;

wherein:

theta (t) is a specific parameter optimal azimuth angle change rule function to be searched and solved; theta is an observed value of the azimuth angle of the moving target;

obtaining the optimal high-low angle change rule function of the specific parameters for searching;

and (4) obtaining the observed value of the elevation angle of the moving target.

The invention has the advantages that:

a target motion rule is established, and the target motion rule can be used for estimating target positioning information at any moment;

the LM algorithm is used for fitting a nonlinear function, target azimuth angle and elevation angle change rule parameters can be obtained only by a small number of samples (5-10 observation data), the operation speed is high, and the real-time performance is strong;

after acquiring the target azimuth angle and the change rule parameters of the elevation angle, carrying out track extrapolation according to the change rule of the target angle;

according to the target angle change rule, the observation data can be smoothed, the problem of poor quality of the observation data can be effectively solved, and the track quality is improved.

Drawings

Fig. 1 is a schematic diagram of a ground rectangular coordinate system established by the present invention.

Fig. 2 is a flow chart of the observation whistle for acquiring the air by using a digital telescope.

Fig. 3 is a schematic diagram of target motion simulation parameter settings.

FIG. 4 is a graph of a typical target azimuth change.

Fig. 5 is a graph of typical target elevation angle variation.

FIG. 6 is a schematic diagram of the observed azimuth and the estimated value of the target.

FIG. 7 is a diagram illustrating observed elevation and dip angles of a target and an estimated value.

FIG. 8 is a schematic diagram of estimating target slope distance from measured data.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

The invention provides a moving target track acquisition method based on a single observation whistle digital telescope, which comprises the following steps:

step 1, the ground observation post continuously tracks a moving target by using a digital telescope, acquires observation data and transmits the observation data to a command information center platform end through a wireless network.

As shown in figure 1, the ground observation whistle is positioned at the origin of a coordinate system in the northeast, and when the handheld digital telescope stably tracks a target, the angle data of the target can be recorded. The data sampling period can be flexibly set according to the moving condition of the target, and when the moving target is far away, the observed data change is slow, and the sampling interval is properly increased; when the moving target is closer and the state of the moving target changes rapidly, the sampling frequency should be properly increased and the sampling interval should be decreased. After the target air condition data is recorded, the target air condition data is transmitted to the command center platform through a wireless network, as shown in fig. 2.

The observation data acquired by the digital telescope comprises real-time azimuth angle theta and elevation angle of the moving targetThe digital telescope automatically records station numbers of observation points and automatically generates batch numbers of observation targets, and the types of the targets are manually selected by an observer. The observation data acquired by the digital telescope is a time sequence.

And 2, preprocessing the observation data (the step is a step for further improving the track precision and can be omitted):

2.1) removing repeated data in the observation data, and interpolating:

due to human factors, when a moving target is observed, repeated data can be generated when the telescope is stopped, and t is transmitted₁The observed data of the time are recorded as

t₂The observed data of the time are recorded asThe observed data of the time are recorded asIf t_iTime and t_jTime of day, theta_i＝θ_j，

Then order

The i ≠ j, i ≠ 1,2, … n, j ≠ 1,2, … n;

2.2) eliminating the excessively deviated data in the observed data, and interpolating:

2.2.1) continuously observing any moving target for many times by using a digital telescope to obtain a large amount of observation data;

2.2.2) calculating the deviation variance between the observation data and the azimuth angle and elevation angle estimated values of the moving target by using the following formulas respectively for the observation data obtained by each continuous observation;

wherein:

is t_iAn azimuthal observation of the time;

is t_iA time azimuth angle estimation value;is t_iA time elevation angle observation value;

is t_iThe elevation angle estimate of the time.

2.2.3) calculating the average value of the variance of the target azimuth angle and elevation angle observation data in the step 2.2.2), and recording the average value as

And

the mean value of standard deviation is obtained by evolution

And

2.2.4) observing said step 1)Comparing the azimuth angle and the elevation angle corresponding to each moment in the data with the average value obtained in the step 2.2.3), and if a certain moment t_kThe corresponding azimuth deviation (deviation of azimuth from its estimated value) is greater than or equal to the average value

3-5 times of the azimuth angle theta_kIf the deviation is too large, letIf a certain time t_gCorresponding high and low angles

The deviation (the deviation of the elevation angle from its estimated value) is equal to or greater than the average value

3-5 times of the angle of elevation, representing the elevation angle

If the deviation is too large, let

Step 3, establishing an angle information change rule of the moving target:

in a short time, assuming that the motion state of the target remains unchanged, according to the geometric relationship in fig. 1, the change rule of the azimuth angle is derived by using the triangle correlation theorem:

θ＝arctan[a(t-t_x)]+θ_x

similar to the azimuth angle, the change rule of the elevation angle is deduced:

in the formula: { a, t_x,θ_xThe azimuth angle change rule parameter is the target azimuth angle change rule parameter, and for a target (a, t) in uniform linear motion_x,θ_xThe three parameters are constants; the specific meanings of the parameters are: a-v/r_xV is the velocity of the target, r_xIs a shortcut for the airway; t is t_xIs the time theta corresponding to the flying time of the target to the short-cut of the air route_xThe azimuth angle corresponding to the target route shortcut is obtained; { a, b, t_xThe method is characterized in that the parameters of the high-low angle change rule of the target are { a, b, t, for the target which moves linearly at a constant speed }_xThree parameters are constants, where b is h/r_xH is the height of the target; as shown in figure 3, the parameters corresponding to the motion of the target are set, the initial azimuth angle of the target is pi/4, the flight direction is pi, the horizontal distance between the target and the observation whistle is 5000m, the target speed is 240m/s, and the target height is 1000m, and the azimuth angle and elevation angle change curves can be obtained according to the target motion rule formula, as shown in figures 4 and 5, while in reality, the target motion rule parameters are unknown.

Step 4, solving the azimuth angle change rule parameters { a, t of the moving object_x,θ_xAnd elevation angle change law parameter { a, b, t }_x}：

Azimuth angle theta of moving object recorded by digital telescope ═ theta₁,θ₂,…,θ_nAnd high and low anglesAfter the data time sequence, theoretically only three groups of data are needed, and the azimuth angle change rule parameters { a, t) of the target can be solved according to the equation set in the step 3)_x,θ_xAnd elevation angle change law parameter { a, b, t }_x}; in practice, the parameters { a, t } are accurately estimated_x,θ_xAnd { a, b, t }_xMore observation data is needed, because the observation data has certain error with the actual motion track of the target, the quality of the information of the empty situation is related to a plurality of factors, and the observation result of the target is a non-stable random process.

The estimation of parameters of the variation rule of the azimuth angle and the elevation angle of the target is the basis of distance tracking. Solving the angle information change rule of the maneuvering target is a nonlinear optimization problem, and firstly, a function e is constructed_θAnd

then using LM algorithm, search the observation data by knowing azimuth angle and elevation angle to make function e_θAndminimized parameter set { a, t_x,θ_xAnd { a, b, t }_xObtaining a motion rule parameter of the moving target;

wherein:

theta (t) is a specific parameter optimal azimuth angle change rule function to be searched and solved; theta is an observed value of the azimuth angle of the moving target;

obtaining the optimal high-low angle change rule function of the specific parameters for searching;

and (4) obtaining the observed value of the elevation angle of the moving target.

It should be noted that the motion state of the aerial target changes in real time, and the target motion parameters must be estimated online by using short-time observation data to improve the tracking accuracy of the target distance.

LM (Levenberg-Marquardt, Levenberg-Marquardt method) algorithm for solving target motion law parameter { a, t_x,θ_xAnd { a, b, t }_xThe algorithm belongs to one of hill climbing methods, is the most widely used nonlinear least square parameter estimation algorithm, and has the advantages of a gradient method and a Newton method.

Step 5, the target obtained in the step 4 is processedAzimuthal variation law parameter { a, t_x,θ_xAnd elevation angle change law parameter { a, b, t }_xSubstituting the obtained value into a corresponding angle change rule formula in the step 3 to calculate an estimated value of the azimuth angle of the moving target at the moment t

And the estimated value of the elevation angle at the time t

The air condition quality of actual observation data is influenced by various factors and has certain jitter, the observed value and the estimated value of the angle information of the target in a certain experiment are respectively compared in the images 6 and 7, obviously, the estimated value is smoother, the actual observation data fluctuates up and down around the estimated value, the target slope distance is calculated by utilizing the estimated values of the azimuth angle and the elevation angle, and the accuracy is higher.

And 6, calculating the slant distance R of the moving target relative to the digital telescope by using the estimated values of the azimuth angle and the elevation angle:

in the formula:

v₀the estimated speed of the moving target is a key parameter influencing the estimation precision of the target distance. The target speed is required to be preset according to the type of the target before distance estimation, and because the low altitude penetration target usually adopts a high-speed horizontal linear motion mode, the estimated speed v of the engineering target₀190-240m/s can be taken. Fig. 8 is a target slope distance variation curve obtained in a certain experiment.

Step 7, in order to adapt to the tracking of the high maneuvering target, a small amount of latest time sampling observation data is used as input, the slope distance of the moving target is iteratively estimated, and the slope distance time sequence R of the moving target is obtained, wherein R is { R ═ R {₁,R₂,…,R_nDetermine the track of the moving object

As shown in the following tableShown in the figure.

It should be noted that the calculation of the target slant range is not applicable to the small-route short-cut target, in an extreme case, the target route short-cut is zero, the azimuth angle is not changed, and the tracking of the small-route short-cut moving target distance needs to be considered separately.

For the judgment of whether the target is a small-route shortcut target or a non-small-route shortcut target, the following method is adopted:

estimating a target motion rule by using N observation points, wherein the value of N is related to the target speed and the observation sampling period, the suggested value of N is 5-10, and if the azimuth angles of the N observation points meet the following conditions: theta_i+N-1-θ_i∈(θ_l,θ_u)，θ_iIs the azimuth angle (i.e. t) of the ith observation point_iAzimuthal observation of time), θ_i+N-1Is the azimuth angle (i.e. t) of the i + N-1 th observation point_i+N-1Azimuthal observation of time), θ_lIs a lower limit value of θ_uIf the target is the upper limit value, the moving target is considered to be a small navigation path shortcut target, otherwise, the moving target is a non-small navigation path shortcut target.