A projectile navigation method based on dual data link assistance

Abstract

This invention relates to the field of inertial navigation technology, and particularly to a missile navigation method based on dual data link assistance. The method includes: a ground signal receiver acquiring the distance between the missile's position and the ground signal receiver at two adjacent moments via a data link; projecting the distances at the two moments onto the launch coordinate system to calculate the trajectory at each moment; converting the trajectory information to a geodetic rectangular coordinate system, and then to a geographic coordinate system; using the longitude, latitude, altitude, and heading angle in the geographic coordinate system, combined with the inertial navigation's azimuth velocity, eastward velocity, northward velocity, longitude, latitude, and altitude, as observations for Kalman filtering; correcting the missile's position information through Kalman filtering to obtain the final missile position; this invention employs a data link-assisted navigation system to ensure high-precision flight trajectory and attitude of the missile even when GPS is interfered with.

Description

Technical Field

[0001] This invention relates to the field of inertial navigation technology, and in particular to a projectile navigation method based on dual data link assistance. Background Technology

[0002] As a positioning and navigation device, the navigation system provides accurate attitude, velocity, and position information for missile launch, enabling precise target hits. It is a crucial component of the missile launch process. During missile flight, the surrounding airflow is turbulent and complex, and the airspeed measured by the missile's dynamic pressure sensors exhibits a fixed deviation, severely impacting the accuracy of the conductive navigation system. A data link-assisted navigation system can provide the target azimuth angle of the missile relative to the launch point or the data link observation point, improving the missile's navigation position accuracy even in the absence of GPS or with large airspeed measurement errors. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention proposes a projectile navigation method based on dual data link assistance, specifically including the following steps:

[0004] The ground signal receiver obtains the distance between the projectile's position and the ground signal receiver at two adjacent moments via a data link;

[0005] The distance between the two moments is projected onto the launch coordinate system, and the trajectory at the two moments is calculated. The trajectory information is then converted to the geodetic rectangular coordinate system and then to the geographic coordinate system.

[0006] The longitude, latitude, altitude, and heading angle in the geographic coordinate system, combined with the inertial navigation's azimuth velocity, eastward velocity, northward velocity, longitude, latitude, and altitude, will be used as the observations for Kalman filtering.

[0007] The projectile's position information is corrected by Kalman filtering to obtain the final projectile position.

[0008] Furthermore, the distances between the projectile and the ground signal receiver at two adjacent moments are projected onto the launch coordinate system, including:

[0009]

[0010]

[0011]

[0012] in, Let P1 be the coordinates of the projectile in the launch frame; For the projectile located at P t+1 The coordinates of the time in the launch frame; R L1R represents the distance of the projectile relative to the ground control station when it is located at P1. L2 For the projectile located at P t+1 q1 is the distance relative to the ground control station; q2 is the elevation angle of the missile body relative to the origin ground control station in the launch coordinate system; ψ is the heading angle of the missile body in the launch coordinate system.

[0013] Furthermore, the process of converting track information to a geodetic rectangular coordinate system includes:

[0014]

[0015] Among them, (x e ,y e ,z e R represents the geocentric rectangular coordinates of the projectile's real-time position; N Let (λ,L,h) be the radius of curvature of the meridian circle, and (λ,L,h) be the coordinates output by the navigation system, where λ represents longitude, L represents latitude, and h represents altitude. This represents the coordinates of the projectile in the launch frame. This is the transformation matrix between the launch coordinate system and the geocentric rectangular coordinate system.

[0016] Furthermore, the transformation matrix between the launch coordinate system and the geocentric rectangular coordinate system. Represented as:

[0017]

[0018] Where α is the launch azimuth angle.

[0019] Furthermore, during flight, when the projectile receives heading angle observation data from dual data links, the observation data adjusts the predicted heading angle of the inertial measurement unit (IMU) to obtain the optimal estimate of the measured parameter. This optimal estimate is then used as the initial value for the IMU at the next moment, and the simulated heading angle is obtained by integration. When encountering dual data link observation data at the next moment, the above steps are repeated to continuously predict and update the model. Specifically, this includes the following steps:

[0020]

[0021]

[0022]

[0023]

[0024]

[0025] in, M is the predicted heading angle of the projectile at time k+1; k,k+1 The state transition relationship from time k to time k+1; Let k be the analyzed value of the projectile's heading angle at time k; Let be the error covariance matrix of the predicted value at time k+1; For M k,k+1 transpose; Let Q be the error covariance matrix of the analyzed values ​​at time k; k Obtain the error variance matrix of the heading angle for dual data links; The state analysis value of the projectile's heading angle at time k+1; K represents the predicted heading angle of the projectile at time k+1; k+1 Let be the gain matrix at time k+1; H is the observed heading angle at time k+1; k+1 For observation operators, that is, the functional relationship between observed values ​​and state values; Let be the error covariance matrix of the predicted value at time k+1; Let be the error covariance matrix of the analytical values ​​at time k.

[0026] Furthermore, the trajectory R at two adjacent moments in the dual data link... L The heading angle ψ of the projectile in the launch coordinate system is calculated using differential calculation. This heading angle at time k+1 is then used as the observation value for Kalman filtering. The calculation process for the heading angle includes:

[0027] Ψ = arctan(Δy / Δx)

[0028] Where Δy is the value obtained through the trajectory R L The difference in the vertical axis distance calculated by differential calculation, Δx is the distance through the track R. L The difference in horizontal axis distance calculated using differential calculation.

[0029] The present invention provides a navigation system based on dual data links that can acquire the position information of the missile relative to the observation point during its flight. Furthermore, it can obtain the missile's flight speed by integrating the missile's trajectory over time between two adjacent moments. Using this position and speed information, the system can make short-term corrections to the missile's position and speed, enabling precise navigation of the missile in situations where GPS signals are temporarily unavailable due to weather or other environmental factors, and allowing it to hit the target. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the model used in the projectile navigation method based on dual data links of the present invention;

[0031] Figure 2 This is a schematic diagram illustrating the calculation of the heading angle observations during the Kalman filtering process in this invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] To overcome the shortcomings of existing technologies, this invention proposes a projectile navigation method based on dual data link assistance, such as... Figure 1 Specifically, it includes the following steps:

[0034] The ground signal receiver obtains the distance between the projectile's position and the ground signal receiver at two adjacent moments via a data link;

[0035] The distance between the two moments is projected onto the launch coordinate system, and the trajectory at the two moments is calculated. The trajectory information is then converted to the geodetic rectangular coordinate system and then to the geographic coordinate system.

[0036] The longitude, latitude, altitude, and heading angle in the geographic coordinate system, combined with the inertial navigation's azimuth velocity, eastward velocity, northward velocity, longitude, latitude, and altitude, will be used as the observations for Kalman filtering.

[0037] The projectile's position information is corrected by Kalman filtering to obtain the final projectile position.

[0038] In this embodiment, addressing the issues of GPS being susceptible to interference due to environmental factors such as weather during missile flight, which affects the accuracy of the navigation system, this invention provides a navigation system based on dual data links. This system can provide precise position information of the missile and trajectory information between two adjacent moments, providing strong technical support for fused navigation and ensuring that the navigation system can maintain high-precision flight and target hit even without GPS.

[0039] Before the projectile is launched, the transformation matrix between the geocentric rectangular coordinate system (e-frame) and the launch coordinate system (f-frame) needs to be calculated, as shown in the following formula:

[0040]

[0041] In the formula Let f be the transformation matrix from the n-system to the f-system; α is the transformation matrix from the e-system to the n-system; (λ,L,h) represents the location information of the launch point in the geographic coordinate system; α is the launch azimuth angle.

[0042] Navigation information conversion includes position information, velocity information, and attitude information. The specific calculation method is as follows:

[0043] (1) Location information conversion

[0044] The conversion of position information requires the geocentric rectangular coordinates of the launch point, the geocentric coordinates of the projectile's real-time position, and the transformation matrix. The specific calculation method is as follows:

[0045]

[0046]

[0047]

[0048] In the formula (x f ,y f ,z f (x) represents the real-time position of the projectile in the launch coordinate system; e ,y e ,z e (x) represents the geocentric rectangular coordinates of the projectile's real-time position, which can be obtained by substituting the navigation system output data (λ,L,h) into equation (3); 0ef ,y 0ef ,z 0ef The coordinates of the launch point are the geocentric rectangular coordinates, which can be obtained by substituting the geographic coordinates (λ0, L0, h0) of the launch point into equation (3); R N Let R be the radius of curvature of the meridian, which is the semi-major axis of the Earth. e The Earth's oblateness e and latitude L are calculated from this.

[0049] (2) Speed ​​information conversion

[0050] During the speed information conversion process, the speed information output by the navigation system can first be converted from the navigation coordinate system (n system) to the geocentric rectangular coordinate system (e system), and then converted to the launch coordinate system (f system).

[0051]

[0052] In the formula This represents the real-time velocity of the projectile in the launch coordinate system. Output speed information to the navigation system; The transformation matrix from the n-system to the e-system is calculated from the geographic coordinates (λ0, L0, h0) of the launch point and the launch azimuth angle α. The transformation matrix from the e-system to the f-system can be calculated from the real-time geographic coordinate system (λ,L,h) of the projectile.

[0053] (3) Attitude information conversion

[0054] If the missile's onboard control system uses the attitude angles in the launch coordinate system, then the orientation relationship between the missile's body coordinate system (b-frame) and the launch coordinate system (f-frame) must be determined.

[0055]

[0056] In the formula Let f be the transformation matrix from the b-system to the f-system.

[0057] During the missile's flight, dual data links assist in calculating the missile's position information in the launch coordinate system and its trajectory information between two time points. The specific steps are as follows:

[0058]

[0059]

[0060]

[0061] In the formula Let P1 be the coordinates of the projectile in the launch frame; For the projectile located at P t+1 The coordinates of the time in the launch frame; R L1 R represents the distance between the projectile and the ground control station when the projectile is at position P1, measured by the data link; L2 For the projectile located at P t+1 The distance relative to the ground control station is measured by the data link; q1 is the elevation angle of the missile body relative to the origin ground control station in the launch coordinate system; q2 is the elevation angle of the missile body relative to the origin ground control station in the launch coordinate system; ψ is the heading angle of the missile body in the launch coordinate system, obtained from the trajectory R of two adjacent moments in the dual data link. L This is derived from the difference principle.

[0062] (2) Calculate the position of the projectile in the geocentric rectangular coordinate system.

[0063]

[0064] Among them, (x e ,y e ,z e R represents the geocentric rectangular coordinates of the projectile's real-time position; N Let (λ,L,h) be the radius of curvature of the meridian circle, and (λ,L,h) be the coordinates output by the navigation system, where λ represents longitude, L represents latitude, and h represents altitude. This represents the coordinates of the projectile in the launch frame. This is the transformation matrix between the launch coordinate system and the geocentric rectangular coordinate system.

[0065] Transformation matrix between launch coordinate system and geocentric rectangular coordinate system Represented as:

[0066]

[0067] Where α is the launch azimuth angle.

[0068] (3) Kalman filtering for fusion navigation

[0069] The system combines the longitude, latitude, and altitude of the missile at a certain moment during its flight, obtained from the dual data links, the heading angle obtained from the track difference measured at two moments, and the velocity information measured by the airspeed meter. This information is then fused with Kalman filtering to obtain the optimal position, velocity, and heading information of the missile at a certain moment, thus enabling accurate navigation of the missile in the absence of GPS during its flight.

[0070] In this embodiment, during the flight of the missile, when heading angle observation data is obtained from dual data links, the observation data adjusts the predicted heading angle of the inertial measurement unit to obtain the optimal estimated value of the measured parameter. This optimal estimated value is used as the initial value of the inertial measurement unit at the next moment, and the simulated heading angle value is obtained by integration. When encountering dual data link observation data at the next moment, the above steps are repeated to continuously predict and update the model. Specifically, the following steps are included:

[0071]

[0072]

[0073]

[0074]

[0075]

[0076] in, M is the predicted heading angle of the projectile at time k+1; k,k+1 The state transition relationship from time k to time k+1; Let k be the analyzed value of the projectile's heading angle at time k; Let be the error covariance matrix of the predicted value at time k+1; For M k,k+1 transpose; Let Q be the error covariance matrix of the analyzed values ​​at time k; k Obtain the error variance matrix of the heading angle for dual data links; The state analysis value of the projectile's heading angle at time k+1; K represents the predicted heading angle of the projectile at time k+1; k+1 Let be the gain matrix at time k+1; H is the observed heading angle at time k+1; k+1 For observation operators, that is, the functional relationship between observed values ​​and state values; Let be the error covariance matrix of the predicted value at time k+1; Let be the error covariance matrix of the analytical values ​​at time k.

[0077] like Figure 2 The trajectory R between two adjacent moments in the dual data link L The heading angle ψ of the projectile in the launch coordinate system is calculated using differential calculation. This heading angle at time k+1 is then used as the observation value for Kalman filtering. The calculation process for the heading angle includes:

[0078] Ψ = arctan(Δy / Δx)

[0079] Where Δy is the value obtained through the trajectory R L The difference in the vertical axis distance calculated by differential calculation, Δx is the distance through the track R. L The difference in horizontal axis distance calculated using differential calculation.

[0080] In the description of this invention, it should be understood that the terms "coaxial," "bottom," "one end," "top," "middle," "other end," "upper," "side," "top," "inner," "outer," "front," "center," "both ends," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0081] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "rotation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0082] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A projectile navigation method based on dual data link assistance, characterized in that, Specifically, the following steps are included: The ground signal receiver obtains the distance between the projectile's position and the ground signal receiver at two adjacent moments via a data link; The distance between two moments projected onto the launch coordinate system includes: in,( () represents the coordinates of the projectile in the launch frame when it is located at P1; ) is the projectile located at P t+1 The coordinates of the time in the launch frame; R L1 R represents the distance of the projectile relative to the ground control station when it is located at P1. L2 For the projectile located at P t+1 q1 and q2 are the distances relative to the ground control station at two different moments in the launch coordinate system, and ψ is the elevation angle of the missile body relative to the origin ground control station. The flight paths at two different times are calculated, and the flight path information is converted to a geodetic rectangular coordinate system, and then to a geographic coordinate system. The longitude, latitude, altitude, and heading angle in the geographic coordinate system, combined with the inertial navigation's azimuth velocity, eastward velocity, northward velocity, longitude, latitude, and altitude, will be used as the observation values ​​for Kalman filtering. After Kalman filtering, the missile's position information is corrected. Specifically, during flight, when heading angle observation data from dual data links is available, the observation data adjusts the predicted heading angle of the inertial measurement unit (IMU) to obtain the optimal estimate of the measured parameter. This optimal estimate is then used as the initial value for the IMU at the next moment, and integration yields the simulated heading angle value. When encountering dual data link observation data at the next moment, the above steps are repeated to continuously predict and update the model. Specifically, the steps include: in, The predicted heading angle of the projectile at time k+1; The state transition relationship from time k to time k+1; Let k be the analyzed value of the projectile's heading angle at time k; Let be the error covariance matrix of the predicted value at time k+1; for transpose; Let be the error covariance matrix of the analytical values ​​at time k; Obtain the error variance matrix of the heading angle for dual data links; The state analysis value of the projectile's heading angle at time k+1; The predicted heading angle of the projectile at time k+1; Let be the gain matrix at time k+1; The heading angle observation value at time k+1; For observation operators, that is, the functional relationship between observed values ​​and state values; Let be the error covariance matrix of the analytical values ​​at time k+1; Let be the covariance of the observation noise at time k+1; The trajectory R between two adjacent moments of the dual data link L The heading angle ψ of the projectile in the launch coordinate system is calculated using differential calculation. This heading angle at time k+1 is then used as the observation value for Kalman filtering. The calculation process for the heading angle includes: Ψ = arctan(Δy / Δx) Where Δy is the value obtained through the trajectory R L The difference in the vertical axis distance calculated by differential calculation, Δx is the distance through the track R. L The difference in horizontal axis distance calculated using differential calculation.

2. The projectile navigation method based on dual data link assistance according to claim 1, characterized in that, The process of converting flight track information to a geodetic rectangular coordinate system includes: Among them, (x e ,y e ,z e R represents the geocentric rectangular coordinates of the projectile's real-time position; N Let (λ,L,h) be the radius of curvature of the meridian circle, and (λ,L,h) be the coordinates output by the navigation system, where λ represents longitude, L represents latitude, and h represents altitude. This represents the coordinates of the projectile in the launch frame. This is the transformation matrix between the launch coordinate system and the geocentric rectangular coordinate system.

3. The projectile navigation method based on dual data link assistance according to claim 2, characterized in that, Transformation matrix between launch coordinate system and geocentric rectangular coordinate system Represented as: in, This is the launch azimuth angle.

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