A target absolute geographic coordinate calculation method of known target azimuth and distance information

Abstract

The application relates to the technical field of target orientation, in particular to a target absolute geographic coordinate calculation method of known target orientation distance information, which comprises the following steps: S1: calculating the parameters A of a reference point a 、 A b 、 A R ; S2: estimating the longitude and latitude coordinates (x T ,y T ) of the target according to (theta, rho); S3: calculating the corresponding estimated orientation distance coordinates (theta T , rho T ) according to the estimated longitude and latitude coordinates (x T ,y T ) of the target; S4: calculating the orientation and distance estimation deviation (delta θ , delta ρ ), establishing feedback and updating (theta, rho); S5: substituting the updated (theta, rho) into steps S2-S4, circularly calculating and observing the estimation deviation (delta θ , delta ρ ); S6: if (delta θ , delta ρ ) meets the design index, the cycle is exited, and the estimated longitude and latitude (x T ,y T ) of the target is given. The technical scheme provides a recursive solution method of iterative feedback control. The method has clear physical meaning, fast convergence speed, small iteration number and can quickly and accurately solve the longitude and latitude information of the target.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of target orientation, and particularly relates to a target absolute geographic coordinate calculation method based on known target orientation distance information. BACKGROUND

[0002] 1. Basic situation of traditional technology

[0003] When a sonar detects a target, the orientation-distance measurement information of the target is directly given. In multi-period detection, people not only care about the orientation-distance information of the target, but also care about the mutual position relationship of the target between multiple periods. Converting the orientation-distance information into absolute geographic coordinate information represented by latitude and longitude can directly and intuitively give the target track in multi-period observation, thereby being beneficial to the motion information research and judgment of the target. The existing methods for converting the orientation-distance into latitude and longitude coordinates mainly include the following two ways:

[0004] (1) Approximate rectangular coordinate conversion method: the method regards the earth surface of the sonar as an infinite plane. The coordinate conversion is directly performed according to the conversion mode of polar coordinates into rectangular coordinates.

[0005] (2) Table lookup method: an approximate calculation formula and a net format geographic coordinate mass data are set in advance. The database is looked up according to the current measurement value, and the target track is approximately calculated.

[0006] 2. Defects of traditional technology

[0007] (1) The earth surface is an ellipsoid surface. With the increase of the action distance of the sonar and the accurate analysis demand for the motion elements of the target, the analysis error of the approximate rectangular coordinate conversion method is too large, and the method is not conducive to the acquisition of the fine track of the target.

[0008] (2) The table lookup method has large error of the approximate formula. Especially for the sonar on the autonomous unmanned platform, the data capacity is limited. In the case of limited data capacity, the analysis error is further deteriorated. SUMMARY

[0009] In view of the defects of the prior art, the application provides a target absolute geographic coordinate calculation method based on known target orientation distance information. A model is established according to a standard geographic ellipsoid surface. An accurate calculation formula of latitude and longitude coordinates into orientation-distance coordinates is given (see step S3). In view of the difficulty in analytically expressing the conversion relationship formula of the orientation-distance coordinates into the latitude and longitude coordinates of the geographic ellipsoid surface, the technical solution provides a recursive solution method of iterative feedback control. The method has clear physical meaning, fast convergence speed, small iteration number, and can quickly and accurately solve the latitude and longitude information of the target.

[0010] The application is implemented by the following technical solutions:

[0011] A target absolute geographic coordinate calculation method of known target azimuth distance information, comprising the following steps:

[0012] S1: Calculate the parameters A related to the reference point a , A b , A R ;

[0013]

[0014] S2: Estimate the longitude and latitude coordinates (x T , y T ) of the target according to (θ, ρ);

[0015]

[0016] S3: Calculate the corresponding estimated azimuth distance coordinates (θ T , ρ T ) according to the estimated target longitude and latitude coordinates (x T , y T );

[0017]

[0018] Wherein

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025] S4: Calculate the azimuth and distance estimation deviation (Δ θ , Δ ρ ), establish feedback, and update (θ, ρ);

[0026] Δ θ = θ T - θ

[0027] Δ ρ = ρ T - ρ

[0028] Δ θ = θ T - θ

[0029] Δ ρ = ρ T-ρ

[0030] S5: the updated (θ, ρ) is substituted into steps S2-S4, loop calculation, and the estimated deviation (Δ θ , Δ ρ ) is observed;

[0031] S6: if (Δ θ , Δ ρ ) meets the design index, the loop is exited, and the estimated target longitude (x T , y T ) is given.

[0032] Preferably, in the step S1, the longitude and latitude coordinates (x A , y A ) of the reference point A, the earth major axis a, the earth minor axis b, the target T reference true north direction θ, the distance ρ, and the sign represent the sign function.

[0033] The beneficial effects of the present application are:

[0034] 1. The present application adopts a standard geographic ellipsoid earth longitude and latitude model, which is more in line with the actual situation and is suitable for multi-cycle accurate trajectory description of a sonar target at a large detection distance.

[0035] 2. The present application provides a bearing-distance-to-longitude and latitude coordinate conversion algorithm, which fully considers the sign changes of north-south latitude and east-west longitude, is universal for the entire earth surface, and is suitable for the current national strategy demand of China's deep blue.

[0036] 3. The present application provides an adaptive error feedback control system, which gradually converges through several loop iterations, has a fast convergence speed, and is suitable for real-time solution of target trajectory.

[0037] 4. The present application provides a bearing and distance error precision reaching the order of magnitude of one ten-thousandth, which is far superior to the demand for accurate description of target trajectory. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0039] Fig. 1 is a comparison chart of longitude and latitude estimation and true value in the present application;

[0040] Fig. 2 is a longitude estimation deviation chart in the present application;

[0041] Fig. 3 is the absolute azimuth deviation map in the present application;

[0042] Fig. 4 is the absolute azimuth deviation map in the present application;

[0043] Fig. 5 is the relative distance deviation map in the present application. DETAILED DESCRIPTION

[0044] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0045] Embodiment one:

[0046] Please refer to Figs. 1-5 , the embodiment specifically discloses a technical solution of a target absolute geographic coordinate calculation method with known target azimuth and distance information,

[0047] including the following steps:

[0048] S1: calculating the parameters A related to the reference point a , A b , A R ;

[0049]

[0050] S2: estimating the longitude and latitude coordinates (x T , y T ) of the target according to (θ, ρ);

[0051]

[0052] S3: calculating the corresponding estimated azimuth and distance coordinates (θ T , ρ T ) according to the estimated longitude and latitude coordinates (x T , y T ) of the target;

[0053] wherein

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060] S4: Calculate the azimuth, distance estimation deviation (Δ θ , Δ ρ ), establish feedback, update (θ, ρ);

[0061] Δ θ = θ T - θ

[0062] Δ ρ = ρ T - ρ

[0063] Δ θ = θ T - θ

[0064] Δ ρ = ρ T - ρ

[0065] S5: Substitute the updated (θ, ρ) into steps S2-S4, loop calculation, observe the estimation deviation (Δ θ , Δ ρ );

[0066] S6: If (Δ θ , Δ ρ ) meets the design index, exit the loop and give the estimated target longitude (x T , y T ).

[0067] Preferably, in step S1, the longitude and latitude coordinates (x A , y A ) of the reference point A, the earth's major axis a, the earth's minor axis b; the target T reference true north azimuth is θ, the distance is ρ, and Sign represents the sign function.

[0068] The reference point longitude is 122.9944 and the latitude is 28.7937. The target parameters are shown in Table 1:

[0069] Table 1 Target parameter values

[0070]

[0071] According to the known azimuth-distance information, after 10 loop iterations, the comparison of the calculated longitude and latitude estimates with the true values, the longitude estimation deviation, the latitude estimation deviation, the distance relative error, and the azimuth absolute error are respectively as followsFigs. 1-5 as shown.

[0072] The target azimuth-distance information conversion method provided by the technical solution is practical, fast in convergence, small in calculation error, and accurate in latitude and longitude information obtained through calculation.

[0073] The above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for calculating absolute geographic coordinates of a target with known target azimuth and range information, applied to multi-cycle track detection of an underwater target by a sonar device, characterized in that, The method comprises the following steps: S1: Obtain the reference point A longitude and latitude coordinates (x A ,y A ) of the sonar device, and calculate the reference point related parameters A a , A b , A R based on the long diameter a and short diameter b of the geographic ellipsoid surface earth longitude and latitude model; S2: Estimate the longitude and latitude coordinates (x T ,y T ) of the target from the (0, p) measured by the sonar device; S3: Calculate the corresponding estimated azimuth-range coordinates (Θ T , ρ T ) from the estimated target latitude-longitude coordinates (x T , y T ); Wherein S4: Calculate the azimuth, distance estimation bias (Δ θ ,Δ ρ ), establish an adaptive error feedback control system, update (θ,ρ); Δ θ = θ T - θ Δ ρ = p T - p Δ θ = θ T - θ Δ ρ = p T - p S5: the updated (θ, ρ) is substituted into steps S2-S4, the calculation is cycled, the estimated deviation (Δ θ ,Δ ρ ) is observed; the error is gradually converged through the iterative cycle to solve the target track in real time; S6: If (Δ θ ,Δ ρ ) meets the design index, exit the loop, and give the estimated target longitude and latitude (x T ,y T ); In the step S1, the target T has a true north direction θ and a distance ρ, and Sign represents a sign function.

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