CN104457756B - A kind of sea surface drag localization method based on two-shipper ranging - Google Patents

Abstract

The invention relates to a sea surface object positioning method based on two-aircraft ranging. The method uses two aircrafts to measure their own position information in real time, and uses airborne ranging equipment to measure the distance between the aircraft and the sea surface object. The data fusion technology realizes the time unification of the measurement data. On this basis, the position equations of the sea surface objects are established by using the distance measurement intersection principle, the solution of the equations is solved iteratively, and the fuzzy solutions of the equations are filtered out, and finally the sea surface objects are obtained. Coordinates in the WGS-84 coordinate system, this method reduces the dimensionality of distance measurement information, reduces the complexity of the system, makes the data processing process simpler and more reliable, and enhances real-time performance.

Description

A Sea Surface Object Location Method Based on Dual-aircraft Ranging

technical field

The invention relates to a sea surface object method based on two-machine distance measurement, which is suitable for detecting and locating sea surface objects, and belongs to the field of space-earth information integration information detection.

Background technique

At present, the positioning methods of sea surface objects mainly include the following two types: aircraft carrying a single active radar positioning, multi-radar cooperative passive positioning based on radiation sources, and aircraft carrying visible light/infrared + laser ranging positioning and other positioning methods.

Among them, the positioning of the aircraft carrying a single active radar is to use the active radar to measure the azimuth, pitch angle and distance of the object relative to the aircraft, supplemented by the position and attitude information of the platform to realize the positioning of the target. The positioning accuracy of a single active radar is easily affected by multiple factors such as the position parameters of the platform, the attitude information of the platform, the radar angle measurement information, and the radar ranging information. It is very difficult to achieve precise positioning of objects. In addition, active radar is easily affected by the material of objects.

Passive positioning based on multiple radars is only related to the position information of the aircraft, the time from the radiation source to the radar, and the time synchronization of each aircraft. This method has the advantages of long range and good concealment, but this method requires that the object must radiate Electromagnetic waves cannot locate objects without radiation sources.

The aircraft carries visible light/infrared + laser ranging and positioning method uses visible light/infrared imaging to measure the azimuth and pitch angle of the object relative to the aircraft, and then combines the distance measured by the laser rangefinder with the yaw angle, roll angle and Pitch angle to realize the positioning of the object. This method has high requirements on the accuracy of angle measurement information, and is easily affected by external factors such as weather, and can only locate one target at a time.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a method for locating sea objects based on dual-aircraft ranging. The airborne positioning equipment determines the position of the aircraft itself, combines the above measurement information to establish a set of equations about the position of objects on the sea surface, and solves the set of equations to realize the positioning of the object. This method reduces the dimensionality of ranging information and reduces the complexity of the system. The data processing process is simpler and more reliable, and the real-time performance is enhanced.

Above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

A method for locating objects on the sea surface based on two-machine ranging, comprising the following steps:

Step (1), continuously measuring the positions of the two aircrafts and recording the corresponding measurement moments, obtaining a series of measured values of the aircraft measurement positions and the corresponding measurement moments;

Step (2), using two aircrafts to continuously measure the sea surface objects and record the corresponding ranging time and ranging direction, and obtain a series of ranging values, ranging directions and corresponding measuring values at the ranging time;

Step (3), using the linear interpolation method to obtain the measured position coordinates P ₁ (x ₁ , y ₁ , z ₁ ), P ₂ (x ₂ , y ₂ , z ₂ ); the distance measurement values r ₁ , r ₂ between the two aircraft and the sea surface object;

Step (4), using the WGS-84 ellipsoid model, position coordinates P ₁ (x ₁ , y ₁ , z ₁ ), P ₂ (x ₂ , y ₂ , z ₂ ), the distance between the two aircraft and the sea surface object From the ranging values r ₁ and r ₂ , establish the position equations of sea surface objects, the specific method is as follows:

(1) The representation of the WGS-84 ellipsoid model is as follows:

in:

N is the radius of curvature of the local Maoyou circle;

The long radius of the earth a=6378137m;

The square of the first eccentricity e ² =0.00669437999013;

L _T is the longitude in the WGS-84 earth geodetic coordinate system;

B _T is the latitude in the WGS-84 earth geodetic coordinate system;

H _T is the height in the WGS-84 earth geodetic coordinate system;

For objects floating on the sea surface, its elevation H _T =0, therefore, the WGS-84 ellipsoid model can be rewritten as the following standard form:

(2), according to the measurement position coordinates P ₁ (x ₁ , y ₁ , z ₁ ), P ₂ (x ₂ , y ₂ , z ₂ ); the distance measurement values r ₁ , r between the two aircraft and the sea surface object ₂ Establish the measurement sphere model of the sea surface object, the specific expression form is as follows:

(xx ₁ ) ² +(yy ₁ ) ² +(zz ₁ ) ² ＝r ₁ ² (4)

(3), combine the formulas (3), (4), and (5) together to establish the position equations of the sea surface object, as follows:

Step (5), calculate the position coordinates T (x, y, z) of the sea surface object, the specific method is as follows:

(1) Set the initial position coordinates T ₀ (x ₀ , y ₀ , z ₀ ) of the sea surface object;

(2), substitute the latitude _BT of any aircraft of measurement into formula (2) and calculate and obtain the radius N of the circle;

(3), put N into the formula (6) to get the ternary quadratic equations, solve the two sets of x, y, z values, that is, get the position coordinates of the two sea surface objects, keep the same position coordinates as the distance measurement direction T'(x', y', z'), remove another position coordinate, and calculate the difference between two position coordinates T ₀ (x ₀ , y ₀ , z ₀ ) and T'(x', y', z') the distance between

(4), whether the distance calculated in the judgment step (3) is less than the set threshold;

(5) If it is less than the set threshold, the position coordinate T'(x', y', z') of the sea surface object is the final position coordinate T(x, y, z) of the sea surface object, if it is greater than the set threshold , then calculate the latitude B' _T corresponding to the position coordinates T'(x',y',z') of the sea surface object, substitute the latitude B' _T into the formula (2) to calculate the radius N of the Maoyou circle, and return to step (3).

In the above sea surface object positioning method based on dual-machine ranging, the position T (x, y, z) of the sea surface object obtained in step (5) in the WGS-84 earth rectangular coordinate system is transformed into the WGS-84 earth coordinate system Under the coordinates T (B, L, H), the specific method is as follows:

In the formula, a is the major radius of the earth ellipsoid, b is the short radius of the earth ellipsoid, and e is the first eccentricity of the ellipsoid;

(B, L, H) are the coordinates of the sea surface object in the WGS-84 geodetic coordinate system.

In the above-mentioned sea surface object positioning method based on two-plane ranging, the position of the plane in step (1) is measured using GPS, BD-2 or inertial navigation information.

In the above sea surface object positioning method based on two-machine ranging, the continuous ranging method in step (2) adopts a laser range finder or an active radar ranging method.

The beneficial effect of the present invention compared with prior art is:

(1), the present invention measures the position information of oneself in real time by two aircrafts, and utilizes the airborne ranging equipment to measure the distance between the aircraft and the sea surface object, and realizes the time unification of the measurement data through the multi-source data fusion technology, in On this basis, the position equations of sea surface objects are established by using the ranging intersection principle, the solutions of the equations are iteratively solved, and the fuzzy solutions of the equations are filtered out, and finally the coordinates of sea surface objects in the WGS-84 coordinate system are obtained. Compared with the existing method, the present invention utilizes the principle of ranging intersection to locate the object, and utilizes the feature that the altitude of the object is zero, thereby reducing the dimensionality of the ranging information and reducing the complexity of the system;

(2), the present invention only uses ranging information and positioning information in the positioning process, which reduces the high-precision requirements for attitude measurement information in the traditional method, and reduces the number of devices used, making the data processing process simpler and more reliable , real-time enhancement;

(3), the present invention can locate a single target, and can also realize the simultaneous positioning of multiple objects within the visible range on the sea surface, and has high positioning efficiency for cluster targets and strong practicability;

(4) The present invention is compatible with ranging equipment such as active radar and laser ranging, and is easy to realize all-weather and all-weather working ability;

(5), the present invention adopts iterative method to calculate the position coordinates of sea surface objects, and adopts defuzzification method to remove invalid data, can solve equation group under the situation of insufficient information amount, improves the applicability of solution method.

Description of drawings

Fig. 1 is the flow chart of the sea surface object positioning method of two-machine ranging of the present invention;

FIG. 2 is a schematic diagram of multi-source data time registration in the present invention;

Fig. 3 is a principle diagram of sea surface object positioning according to the present invention.

Specific implementation examples

Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

As shown in Figure 1, it is the flow chart of the sea surface object positioning method of the two-plane ranging of the present invention. The object positioning method of the present invention is mainly divided into aircraft position measurement, aircraft-sea surface object distance measurement, object position equation set-up, intersection equation set solution The specific implementation steps are as follows:

(1) Aircraft position measurement

The position of the aircraft can be measured by GPS, BD-2, inertial navigation information, etc. The position of the aircraft needs to be described in the WGS-84 earth rectangular coordinate system. If the measured aircraft position is not in the WGS-84 earth rectangular coordinate system, coordinate conversion , transform the coordinates to the WGS-84 earth Cartesian coordinate system. While measuring the position of the aircraft, it is necessary to record the measurement time of the position of the aircraft, and obtain a series of measured values of the measured position of the aircraft and the corresponding measurement time.

(2) Distance measurement between aircraft and sea surface objects

Use the ranging equipment carried by the aircraft to measure the distance and measurement direction between the two aircraft and the sea surface object. If there are multiple sea surface objects, the distance between the aircraft and multiple objects can be measured at the same time. While measuring the distance and direction, it is necessary to record the corresponding measurement time to obtain a series of distance measurement information, measurement direction and corresponding measurement values at the time of distance measurement. The distance can be measured using active radar or laser range finder.

(3) Establishment of object position equations

(1), time registration

Figure 2 is a schematic diagram of time registration of multi-source data according to the present invention. The aircraft-sea surface object distance information and the aircraft position information must be measurement information at the same time. Since the position measurement time of the two aircrafts and the measurement time of the distance between the aircraft and the sea surface object may be inconsistent, if they are inconsistent, the measurement data needs to be registered in time. The time registration method adopts the linear interpolation method. The present invention adopts the linear interpolation method to obtain the measured position information P ₁ (x ₁ , y ₁ , z ₁ ), P ₂ (x ₂ , y ₂ , z ₂ ); the ranging information r ₁ , r ₂ between the two aircraft and the sea surface object.

For example: select the distance r ₂ as the time reference, and unify the other three measurement information on the distance r ₂ time reference. Methods as below:

Calculation method of distance r ₁ : According to the ranging information at time t' _m-1 and t' _m as r' _m-1 and r' _m , calculate the distance r ₁ corresponding to β ₁ , as shown in Figure 2, the formula is as follows:

Similarly, the positions β ₃ and β ₂ of the aircraft 1 and the aircraft 2 at time t _m can be calculated.

(2), WGS-84 ellipsoid model

The representation of the WGS-84 ellipsoid model is as follows:

In the formula,

N is the radius of curvature of the local Maoyou circle;

The long radius of the earth a=6378137m;

The square of the first eccentricity e ² =0.00669437999013;

L _T is the longitude in the WGS-84 earth geodetic coordinate system;

B _T is the latitude in the WGS-84 earth geodetic coordinate system;

H _T is the height in the WGS-84 earth geodetic coordinate system.

For objects floating on the sea surface, its elevation H _T =0, therefore, the WGS-84 ellipsoid model can be rewritten as the following standard form:

(3) Sea surface object measurement spherical model

According to the position coordinates P ₁ (x ₁ , y ₁ , z ₁ ), P ₂ (x ₂ , y ₂ , z ₂ ) and The distances r ₁ and r ₂ to the sea surface object measured by the two planes can establish the measurement sphere model of the sea surface object, and the expression form is as follows:

(xx ₁ ) ² +(yy ₁ ) ² +(zz ₁ ) ² ＝r ₁ ² (4)

(4) Combine formulas (3), (4) and (5) together to establish the position equations of sea surface objects, as follows:

(4) Calculate the position T(x, y, z) of the sea surface object

As shown in Fig. 3, it is a principle diagram of sea surface object positioning according to the present invention, in which P ₁ and P ₂ points are the positions of two aircrafts, and T is a sea surface object. The WGS-84 ellipsoid model is an ellipse in the figure, and the center of the circle is the center of mass of the earth. The measurement sphere model determined by the two aircraft is shown in the dotted circle.

In the coordinate equations of the sea surface object constructed in step 3 (4), there are 4 unknowns and 3 equations, and the analytical solution of the equations cannot be obtained. Taking the position measured by any aircraft as the prior point, iteratively solve the equations, and carry out the following calculation process:

(1) Set the initial position T ₀ (x ₀ , y ₀ , z ₀ ) of the sea surface object;

(2), substitute formula (2) with the latitude _BT of any aircraft of measurement and calculate and obtain the radius N of the circle;

(3), put N into formula (6) to get the ternary quadratic equations, solve the two sets of x, y, z values, that is, get the position coordinates of the two sea surface objects, keep the same position as the measurement direction at this moment Coordinate T'(x', y', z'), remove another position coordinate, calculate two positions according to T ₀ (x ₀ , y ₀ , z ₀ ) and T'(x', y', z') distance between coordinates;

(4), judge whether the distance that step (3) obtains is less than the set threshold;

(5) If it is less than the set threshold, the position T'(x', y', z') of the sea surface object is the position T(x, y, z) of the sea surface object; if it is greater than the set threshold, then Calculate the latitude B' _T corresponding to the position T'(x',y',z') of the sea surface object, and substitute the latitude B' _T into formula (2) to calculate the radius N of the Maoyou circle, and return to step (3).

(5) Coordinate transformation of sea surface objects

The position T (x, y, z) of the sea surface object obtained in step (4) under the WGS-84 earth coordinate system is transformed into the coordinate T (B, L, H) under the WGS-84 earth coordinate system, the specific method as follows:

In the formula, a is the major radius of the ellipsoid, b is the minor radius of the ellipsoid, and e is the first eccentricity of the ellipsoid.

(B, L, H) are the coordinates of the sea surface object in the WGS-84 geodetic coordinate system. When locating multiple sea surface objects at the same time, it can be realized by repeating the above process for each object.

Compared with the traditional method, the positioning method of the present invention reduces the use of 2-3 sets of aircraft and measuring equipment, reduces the cost by 30% to 50%, and can realize simultaneous positioning of multiple targets without reducing measurement accuracy and real-time performance.

The above description is only the best specific implementation mode of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of changes or modifications within the technical scope disclosed in the present invention. Replacement should be covered within the protection scope of the present invention.

The content that is not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims (4)

1. a kind of sea surface drag localization method based on two-shipper ranging, it is characterised in that comprise the following steps：

Step (1), two airplane positions are carried out test constantly and to record the corresponding measurement moment, obtain a series of aircrafts and survey Measure the measured value of position and corresponding measurement moment；

Step (2), continuous ranging is carried out to sea surface drag respectively using two airplanes and corresponding ranging moment and ranging is recorded Direction, obtains a series of measured value in distance measurement values and ranging direction and corresponding ranging moment；

Step (3), corresponding two airplane of synchronization obtained under WGS-84 earth right angle coordinate systems using linear interpolation method Measurement position coordinate P₁(x₁, y₁, z₁)、P₂(x₂, y₂, z₂)；Distance measurement value r between two airplanes and sea surface drag₁、r₂；

Step (4), utilize WGS-84 ellipsoidal models, position coordinates P₁(x₁, y₁, z₁)、P₂(x₂, y₂, z₂), two airplanes and sea Distance measurement value r between object₁、r₂, sea surface drag position equation group is set up, specific method is as follows：

(1), the representation of WGS-84 ellipsoidal models is as follows：

$\left\{\begin{array}{c}{x}_{T,e}=\left(N+H_T\right)\cos B_T\cos L_T\\ y_{T,e}=\left(N+H_T\right)\cos B_T\sin L_T\\ z_{T,e}=\[N\left(1-e^2\right)+H_T\]\sin B_T\end{array}\right.---\left(1\right)$

Wherein：

N is local radius of curvature in prime vertical；

$N=\frac{a}{\sqrt{1-e^2{\sin }^2{B}_T}},---\left(2\right)$

Earth major radius a=6378137m；

First eccentricity square e²=0.00669437999013；

L_TFor the longitude under WGS-84 earth ground coordinate systems；

B_TFor the latitude under WGS-84 earth ground coordinate systems；

H_TFor the elevation under WGS-84 earth ground coordinate systems；

For in offshore floating object, its elevation H_T=0, therefore, rewritable WGS-84 ellipsoidal models are following canonical form：

$x^2+y^2+\frac{z^2}{{(1-e^2)}^2}=N^2---\left(3\right)$

(2), according to measurement position coordinate P₁(x₁, y₁, z₁)、P₂(x₂, y₂, z₂)；Distance measurement value between two airplanes and sea surface drag r₁、r₂The measurement sphere model of sea surface drag is set up, form is embodied as follows：

(x-x₁)²+(y-y₁)²+(z-z₁)²=r₁ ² (4)

(x-x₂)²+(y-y₂)²+(z-z₂)²=r₂ ² (5)

(3), by formula (3), (4), (5) simultaneous, the position equation group of sea surface drag is set up, it is as follows：

$\left\{\begin{array}{c}{x}^2+y^2+\frac{z^2}{{(1-e^2)}^2}=N^2\\ {(x-x_1)}^2+{(y-y_1)}^2+{(z-z_1)}^2={r_1}^2\\ {(x-x_2)}^2+{(y-y_2)}^2+{(z-z_2)}^2={r_2}^2\end{array}\right.;---\left(6\right)$

Step (5), resolving draw the position coordinates T (x, y, z) of sea surface drag, and specific method is as follows：

(1) the initial position co-ordinates T of sea surface drag, is set₀(x₀, y₀, z₀)；

(2), with the latitude B of any airplane of measurement_TSubstitute into formula (2) calculating and obtain prime vertical radius N；

(3), bring N into formula (6) and obtain ternary quadratic equation group, solve two groups of x, y, z values, that is, obtain two sea surface drags Position coordinates, reservation and ranging direction identical position coordinates T ' (x ', y ', z '), another position coordinates is removed, two are calculated Individual position coordinates T₀(x₀, y₀, z₀The distance between) and T ' (x ', y ', z ')；

(4), judgment step (3) calculates whether obtained distance is less than given threshold；

(5) if less than the threshold value of setting, sea surface drag position coordinates T ' (x ', y ', z ') is the final position of sea surface drag Coordinate T (x, y, z), if more than the threshold value of setting, calculating sea surface drag position coordinates T ' (x ', y ', z ') corresponding latitude B '_T, by latitude B'_TSubstitute into formula (2) calculating and obtain prime vertical radius N, return to step (3).

2. a kind of sea surface drag localization method based on two-shipper ranging according to claim 1, it is characterised in that：By step (5) position T (x, y, z) of the sea surface drag obtained under WGS-84 earth right angle coordinate systems is transformed to WGS-84 geodetic coordinates Coordinate T (B, L, H) under system, specific method is as follows：

$B=\arctan \frac{z+{\mathrm{be}}^2{\sin }^{3}U}{\sqrt{x^2+y^2}-{\mathrm{ae}}^2{\cos }^{3}U}$

$L=\arctan \frac{y}{x}$

$H=\frac{\sqrt{x^2+y^2}}{\cos B}-N$

In formula,A is the major radius of earth ellipsoid, and b is that the earth is ellipse The short radius of ball, e is the first eccentricity of ellipsoid；

(B, L, H) is coordinate of the sea surface drag under WGS-84 earth coordinates.

3. a kind of sea surface drag localization method based on two-shipper ranging according to claim 1, it is characterised in that：The step Suddenly aircraft position is measured using GPS, BD-2 or inertial navigation information in (one).

4. a kind of sea surface drag localization method based on two-shipper ranging according to claim 1, it is characterised in that：The step Suddenly the continuous distance-finding method in (two) uses laser range finder or Active Radar distance-finding method.