A target positioning method combining vision and satellite navigation

Abstract

The present invention provides a method for joint visual and satellite navigation target positioning, belonging to the field of passive target positioning. This method uses a binocular camera and employs a satellite navigation terminal and an electromagnetic compass to achieve real-time estimation of the position of a non-cooperative target. This method obtains the current position coordinates of the carrier through the satellite navigation terminal, obtains the angle between the normal of the binocular camera and the true north direction through the electronic compass, and calculates the current position of the target through the deviation of the target's projection on the two cameras, the carrier position, and the angle with the true north. This method has the characteristics of simple implementation, small computational amount, and low cost, and has a certain value for popularization.

Description

Technical Field

[0001] The present invention relates to a method for target positioning by combining vision and satellite navigation, which can effectively improve the efficiency of measuring the target position and belongs to the field of passive target positioning. Background Art

[0002] Satellite navigation systems play an important role in determining the position of the carrier itself. With the emergence of various enhancement technologies, the positioning accuracy has also been greatly improved. At the same time, by deploying two sets of satellite navigation receiving systems, the azimuth angle of the carrier can also be determined, and the angle between the carrier direction and true north can be obtained. However, relying on the satellite navigation system can only obtain the information of the position where the navigation terminal itself is located.

[0003] Vision technology imitates human binoculars to perceive distance. By using two cameras with the same parameters but different positions to replace human eyes, synchronous image acquisition of the same target is carried out. By comparing the position differences of the target in the two images, the distance information of the target is calculated. However, this technology can only obtain the distance between the target and the observation point and cannot obtain the absolute position information of the target.

[0004] Therefore, it is necessary to combine the functions of the vision and satellite navigation systems and propose a method for jointly determining the absolute position information of the observed target. However, such a solution does not exist in the prior art. Summary of the Invention

[0005] Aiming at the problem of measuring the true position of the target, the present invention provides a method for target positioning by combining vision and satellite navigation. This method is a passive method for measuring the target position. It adopts a combined positioning method of vision and satellite navigation, uses satellite navigation to determine the absolute position and orientation of the observation point, and uses visual range observation to measure the true position of the target in the coordinate system without actively emitting electromagnetic waves.

[0006] The object of the present invention is achieved as follows:

[0007] A method for target positioning by combining vision and satellite navigation. This method performs target positioning through an observation device mainly composed of a satellite navigation receiver and a binocular camera. The antenna of the satellite navigation receiver is located at the center of the baseline of the two cameras in the binocular camera, and an electronic compass is also provided on the observation device. The method includes the following steps:

[0008] (1) Use the satellite navigation receiver to determine the absolute position (x M , y M , z M ) of the observation device;

[0009] (2) Determine the angle α between the true north direction and the normal of the current binocular camera according to the electronic compass on the observation device;

[0010] (3) Calculate the positions of the optical centers of the two cameras based on the positioning result of the satellite navigation receiver and the included angle α; assuming the baseline length is d, then there are:

[0011] z L = z M

[0012] z R = z M

[0013] Among them, O L = (x L , y L , z L ) is the position of the optical center of the left camera, and O R = (x R , y R , z R ) is the position of the optical center of the right camera;

[0014] (4) Extract the projection points of the target on the two cameras. The projection points of the target on the left and right cameras are respectively defined as P L = (c x , c y ), and P R = (c' x , c' y );

[0015] (5) Calculate the current position coordinates of the target; if the left camera is used as the reference benchmark, the current position coordinates (x0, y0, z0) of the target are:

[0016]

[0017]

[0018]

[0019] If the right camera is used as the reference benchmark, the current position coordinates (x0, y0, z0) of the target are:

[0020]

[0021]

[0022]

[0023] Among them, f is the focal length of the binocular camera, and T x is the external parameter of the camera.

[0024] The beneficial effects of the present invention are as follows:

[0025] 1. The present invention adopts a passive method, without the need to actively transmit signals, which can effectively improve the measurement efficiency and enhance the concealment of the observation system, and has good application prospects in reconnaissance and target positioning.

[0026] 2. The present invention adopts a positioning method combining vision and satellite navigation. Without actively transmitting electromagnetic waves, it can determine the true position of the target in the coordinate system, enhance the concealment of the observation system, and improve the measurement efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flowchart of the target positioning method combining vision and satellite navigation in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The present invention will be further described in detail below with reference to the accompanying drawings.

[0029] As Figure 1 shown, a target positioning method combining vision and satellite navigation performs target positioning through an observation device mainly composed of a satellite navigation receiver and a binocular camera. The antenna of the satellite navigation receiver is located at the center of the baseline of the two cameras in the binocular camera, and an electronic compass is also provided on the observation device; it includes the following steps:

[0030] (1) Use the satellite navigation receiver to determine the absolute position (x M , y M , z M ) of the observation device;

[0031] (2) Determine the angle α between the true north direction and the normal of the current binocular camera according to the electronic compass on the observation device;

[0032] (3) Calculate the positions of the optical centers of the two cameras according to the positioning result of the satellite navigation receiver and the angle α; assuming the baseline length is d, then there are:

[0033] z L = z M

[0034] z R = z M

[0035] Among them, O L =(x L , y L , z L ) is the optical center position of the left camera, O R =(x R , y R , zR ) is the optical center position of the right camera; z L = z R = z M It is assumed that the binocular cameras are on the same horizontal plane;

[0036] (4) Extract the projection points of the target on the two cameras. The projection points of the target on the left and right cameras are defined as P L = (c x , c y ), P R = (c' x , c' y );

[0037] (5) Calculate the current position coordinates of the target; If the left camera is used as the reference benchmark, the current position coordinates (x0, y0, z0) of the target are:

[0038]

[0039]

[0040]

[0041] If the right camera is used as the reference benchmark, the current position coordinates (x0, y0, z0) of the target are:

[0042]

[0043]

[0044]

[0045] Among them, f is the focal length of the binocular camera, and T x is the external parameter of the camera.

[0046] Furthermore, substituting the position coordinates of the carrier with the left camera as the reference benchmark, we can get:

[0047]

[0048]

[0049]

[0050] In summary, the method of the present invention utilizes a binocular camera and employs a satellite navigation terminal and an electromagnetic compass to achieve real-time estimation of the position of a non-cooperative target. This method obtains the current position coordinates of the carrier through the satellite navigation terminal, obtains the angle between the normal of the binocular camera and the true north direction through the electronic compass, and calculates the current position of the target based on the deviation of the target's projection on the two cameras, the position of the carrier, and the angle with the true north. This method is characterized by simple implementation, small computational amount, and low cost, and has a certain value for popularization.

Claims

1. A target positioning method combining vision and satellite navigation, characterized in that, Target positioning is performed through an observation device mainly composed of a satellite navigation receiver and a binocular camera. The antenna of the satellite navigation receiver is located at the center of the baseline of the two cameras in the binocular camera, and an electronic compass is also provided on the observation device; the method includes the following steps: (1) Determine the absolute position (x M , y M , z M ) of the observation device using a satellite navigation receiver; (2) Determine the angle α between the true north direction and the normal of the current binocular camera according to the electronic compass on the observation device; (3) Calculate the positions of the optical centers of the two cameras according to the positioning result of the satellite navigation receiver and the angle α; assuming the baseline length is d, then there is: Among them, O L =(x L , y L , z L ) is the optical center position of the left camera, and O R =(x R , y R , z R ) is the optical center position of the right camera; (4) Extract the projection points of the target on the two cameras. The projection points of the target on the left and right cameras are respectively defined as P L =(c x , c y ), P R =(c' x , c' y ); (5) Calculate the current position coordinates of the target; if the left camera is used as the reference benchmark, the current position coordinates (x0, y0, z0) of the target are: If the right camera is used as the reference benchmark, the current position coordinates (x0, y0, z0) of the target are: where f is the focal length of the binocular camera, and T x is the external parameter of the camera.

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