KR20150083161A - Method and Apparatus for Error Correction of Global Navigation Satellite System Signal using Imaging Sensor - Google Patents

Abstract

The present invention relates to a method and an apparatus to calibrate errors of GNSS positioning signals inevitably generated due to signal disturbance due to GNSS signal shielded area, the mechanical limits of GNSS receivers in readiness state, disposition of a satellite and a ground object using an image sensor.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method and an apparatus for correcting an error of a satellite navigation system signal using an image sensor,

The present invention relates to a method and an apparatus for correcting an error of a positioning signal in a Global Navigation Satellite System (GNSS) such as a Global Positioning System (GPS), and more particularly, And more particularly, to a method and apparatus for correcting a positioning error of a GNSS signal inevitably caused by a satellite arrangement and a signal disturbance caused by a ground object by using an image sensor.

Due to the continuous development of the GNSS, the position information calculated from the GNSS signal provides high positioning accuracy. As the use of personal GNSS equipment such as navigation and smart phone equipped with GPS receiver is increasing, . However, it is not easy to receive GNSS signals from satellites stably in all regions due to environmental factors such as GNSS satellites, receiver mechanical limitations, atmospheric conditions, or satellite positioning.

At least four visible satellites must be secured for stable GNSS signal measurements. In urban areas, however, it is difficult to obtain the number of visible satellites, which causes frequent signal occlusion. Also, the performance of the GNSS in the urban area is significantly degraded due to the multipath errors received on the surface of the building. Nevertheless, the use of satellite navigation systems in urban areas is still increasing and has attracted attention as an infrastructure technology for precision navigation. Therefore, it is necessary to develop a navigation technology that can maintain high accuracy by correcting the GNSS signal.

In order to correct the error of the GNSS signal, a first receiver is installed at a known coordinate reference point by a method called DGPS (Differential GPS), that is, a relative positioning using two or more GNSS receivers, A method of accurately calculating the distance error correction value of the second receiver and using it for error correction of the second receiver has been used. Also, a method of broadcasting a distance error correction value of an individual satellite by using a satellite broadcasting or other broadcasting means, receiving it by a receiver, and using it for error correction of a receiver is used. Also, a method has been proposed in which a receiver (or an object) broadcasts a corresponding position using a communication device mounted on a receiver (or an object) that knows an accurate magnetic position and corrects the position error by receiving the receiver. However, the above-mentioned DGPS method or individual satellite distance error correction broadcasting methods are still based on the reception of the GNSS signals, and thus can not be applied to the GNSS signal-blocking areas such as the urban areas. In the case of the self- It is difficult to identify the object corresponding to the signal.

There have been attempts to compensate GNSS error using an image sensor. However, there have been cases in which the relative position estimation between the moving object and the target, the feature point matching, the edge extraction or the lane extraction have been performed, but the relationship between the image coordinate and the real world coordinate is not accurately estimated And did not achieve a level of accuracy to compensate for the GNSS error.

As a related prior art, Korean Registration No. 10-1241171 (published on Mar. 11, 2013) can be referred to.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to overcome the limitations of the existing GNSS and to provide a GNSS signal-blocking region, a mechanical limit of the GNSS receiver, a standby state, And correcting a positioning error of a GNSS signal using an image sensor in a situation where a GNSS signal is not received or an error occurs due to a signal disturbance caused by a signal of the GNSS signal.

According to another aspect of the present invention, there is provided a method of correcting an error of a GNSS signal, the method comprising: storing image information on a landmark in a database, Storing information; Calculating image coordinates of the landmark included in the image photographed using the image sensor and calculating a photographing position of the image sensor from the image coordinate and the ground position information; And correcting a positioning error of the GNSS signal using the photographing position of the image sensor.

In order to calculate the image coordinates of the landmark, the most similar landmark image among the candidate landmark images of the database within a predetermined distance from the corresponding position of the GNSS positioning information is searched in the image photographed using the image sensor , And analyzes the image coordinates of the corresponding landmark image.

The photographing position of the image sensor is calculated according to the following equation,

Here, the landmark position information (X, Y, Z) of the landmark, the photographing position S _x , S _y , S _{z of the} image sensor, the image coordinates (x, y) of the landmark, ), A ratio coefficient (s), and an element value (r ₁₁ to r ₃₃ ) of the rotational movement transformation matrix.

Wherein the correcting step comprises: calculating a position error between a photographing position of the image sensor and GNSS positioning information at the time of photographing the image by the image sensor; And correcting the GNSS positioning information at a position where the landmark stored in the database does not exist in the image photographed by the image sensor using the position error.

According to another aspect of the present invention, there is provided a positioning apparatus comprising: an image sensor; A database for storing image information on landmarks and corresponding ground position information; A photographing position calculating unit for calculating image coordinates of the landmark included in the image photographed by the image sensor and calculating a photographing position of the image sensor from the image coordinates and the ground position information; And a position correcting unit for correcting the GNSS positioning information using the photographing position of the image sensor. And a GNSS module for generating the GNSS positioning information.

Wherein the photographing position calculating section calculates the photographing position of the landmark in the image captured by using the image sensor in the same manner as that of the candidate landmark images of the database within a predetermined distance from the corresponding position of the GNSS positioning information, Searches the landmark image, and analyzes the image coordinates of the landmark image.

The photographing position calculating unit calculates the photographing position of the image sensor according to the following equation,

Here, the landmark position information (X, Y, Z) of the landmark, the photographing position S _x , S _y , S _{z of the} image sensor, the image coordinates (x, y) of the landmark, ), A ratio coefficient (s), and an element value (r ₁₁ to r ₃₃ ) of the rotational movement transformation matrix.

Wherein the position correction unit calculates a position error between a photographing position of the image sensor and a positioning information of the GNSS module at the time of photographing the image by using the position error, And corrects the positioning information of the GNSS module at a position where there is no landmark stored in the database.

According to the method and apparatus for compensating the error of a GNSS signal according to the present invention, it is possible to prevent the occurrence of a GNSS signal due to a GNSS signal blocking region, a mechanical limit of the GNSS receiver, a standby state, a satellite arrangement, , Accurate positioning can be performed stably by correcting the positioning error of the GNSS signal in real time using the image sensor.

1 is a view for explaining a positioning apparatus using a GNSS according to an embodiment of the present invention.
2 is a flowchart illustrating an operation of a positioning apparatus using a GNSS according to an embodiment of the present invention.
3 is a reference diagram for explaining the positioning correction process of FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

1 is a view for explaining a positioning apparatus 100 using a GNSS according to an embodiment of the present invention.

1, a GNSS-based positioning apparatus 100 according to an embodiment of the present invention includes a database 110, a photographing position calculating unit 120, an image sensor 121, a position correcting unit 130, And a GNSS module 140.

Here, the GNSS module 140 is a module having a Global Navigation Satellite System (GNSS), which receives signals from a plurality of satellites and provides GNSS signals, which are positioning information. The GNSS module 140 may be a module for generating a plurality of GPS satellite signals and generating positioning information, a module for receiving a plurality of Global Navigation Satellite System (GLONASS) satellite signals or a plurality of Gallileo satellite signals, Lt; / RTI > Also, the GNSS module 140 may include a module for receiving satellite signals of various types of navigation satellites such as GPS and GLONASS and generating positioning information.

In the database 110, image information on a template image or the like for one or more landmarks such as road signs, traffic lights, traffic signs, and the like present in the real world and real-world terrestrial position information corresponding thereto (e.g., (X, Y, Z)) are stored in advance in the form of a database (S110 in FIG. 2).

The image sensor 121 is a photographing means including a CMOS image sensor, a CCD image sensor, and the like, and captures an image including the above landmark (S120 in FIG. 2).

The photographing position calculating unit 120 refers to the database 110 and when the image captured by the image sensor 121 includes a landmark, the photographing position calculating unit 120 calculates the photographing position of the landmark based on the image coordinate system (two- (x, y) of the corresponding landmark and the image coordinates (x, y) of the corresponding landmark and the ground position information (X, Y, Z) of the corresponding landmark stored in the database 110 (S _x , S _y , S _z ) of the image sensor 121 (S 130 in FIG. 2).

For example, using the initial GNSS signal (or positioning information) acquired by the GNSS module 140 at a position where the image sensor 121 captures, the photographing position calculation unit 120 calculates the photographing position (For example, landmark images within a predetermined distance from the corresponding position according to the corresponding GNSS positioning information) that may exist in the image photographed by the image sensor 121 among a plurality of the plurality of landmarks, And can be set as a comparison target template image.

The photographing position calculation unit 120 calculates the photographing position of the most similar template image (landmark image) set as a candidate in the image (input image) captured by the image sensor 121 The image matching method for searching the wavelet image (the template image in FIG. 3) and analyzing the image coordinates (x, y) is to compare the pattern of the pixel value in the corresponding template image with the pattern of the pixel value of the input image, A pixel correlation based image matching method for finding similar points of pixel value patterns based on similarity, a feature point based image matching method for detecting feature points in a template image and an input image, and determining similarity rolls between feature points, A color information based image matching method for finding a point where the most similar color exists using the color information between the blit image and the input image and determining based on the similarity degree, A frequency-based image matching method in which the frequency characteristics on the frequency domain are analyzed and the frequency domain is estimated from the conversion relationship between the two images. In the detailed image matching method for finding the image coordinates (x, y) in the input image of the template image (landmark image), any one or more of the above methods may be used, or another method may be used.

When the image sensor 121 calculates the image coordinates (x, y) of the landmark of the image photographed by the image sensor 121, the photographing position calculating unit 120 obtains the ground position information of the corresponding landmark stored in the database 110 (S _x , S _y , S _z ) of the image sensor 121 can be calculated by using Equation (1), Y,

[Equation 1]

F is a constant proportional to the focal distance or focal length of the image sensor 121, s is a scale factor, and r ₁₁ to r ₃₃ are rotation speeds for converting an image coordinate system to a ground coordinate system, The element value of the motion transformation matrix.

를 계산하기 위해서는 복수 개의 영상좌표 (x, y)와 지상좌표 (X, Y, Z) 값이 필요하게 된다. 이를 위해서 본 발명에서는 랜드마크의 중심 위치뿐만 아니라 랜드마크의 가장자리 위치에 대한 실세계 지상위치정보가 모두 데이터베이스(110)에 저장되어 사용될 수 있다.(S _x , S _y , S _z ) of the image sensor 121 using Equation (1)

A plurality of image coordinates (x, y) and ground coordinates (X, Y, Z) are required to calculate the image coordinates. To this end, in the present invention, not only the center position of the landmark but also the real world terrestrial position information about the edge position of the landmark can be stored in the database 110 and used.

When the image sensor 121 photographs a plurality of images successively while moving the apparatus 100 while moving the image including the specific landmark, the image position of the landmark detected by the photographing position calculating unit 120 in the previous frame (x, y) and the movement of the device 100, the image coordinates of the image sensor 121 of the next frame may be estimated. The movement variation of the apparatus 100 can be calculated using the GNSS signal (positioning information) of the GNSS module 140. [

On the other hand, the position correcting unit 130 corrects the GNSS signal of the GNSS module 140 (S _x , S _y , S _z ) by using the real world photographing position (S _x , S _y , S _z ) of the image sensor 121 calculated by the photographing position calculating unit 120 Positioning information). Accordingly, it is possible to calculate an accurate position for each position of the section where the landmark does not exist in the image obtained through the image sensor 121. [

For example, the position correcting unit 130 corrects the position of the image sensor 121 based on the real-world photographing positions S _x , S _y , and S _z of the image sensor 121 and the position The difference between the GNSS signals (positioning information) (G _x , G _y , G _z ) of the GNSS module 140 can be calculated as position errors (d _x , d _y , d _z ). Accordingly, the position correcting unit 130 corrects the position (T _x , T _y , T _z ) at which the landmark stored in the database 110 does not exist in the image taken by the image sensor 121, The accurate position information can be estimated by correcting the GNSS positioning information (G _x , G _y , G _z ) using the position error (d _x , d _y , d _z )

&Quot; (2) "

_{(d x, d y, d} z) = (S x, S y, S z) - (G x, G y, G z)

&Quot; (3) "

_{(T x, T y, T} z) = (G x, G y, G z) + (d x, d y, d z)

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

Claims (9)

Storing image information on a landmark and corresponding ground position information in a database;
Calculating image coordinates of the landmark included in the image photographed using the image sensor and calculating a photographing position of the image sensor from the image coordinate and the ground position information; And
And correcting the satellite navigation system (GNSS) positioning information using the photographing position of the image sensor
And correcting the error of the GNSS signal. The method according to claim 1,
In order to calculate the image coordinates of the landmark, the most similar landmark image among the candidate landmark images of the database within a predetermined distance from the corresponding position of the GNSS positioning information is searched in the image photographed using the image sensor And analyzing the image coordinates of the corresponding landmark image. The method according to claim 1,
The photographing position of the image sensor is calculated according to the following equation,

Here, the landmark position information (X, Y, Z) of the landmark, the photographing position S _x , S _y , S _{z of the} image sensor, the image coordinates (x, y) of the landmark, ), The ratio coefficient (s), and the element values (r ₁₁ to r ₃₃ ) of the rotation movement transformation matrix are used. The method according to claim 1,
Wherein the correcting comprises:
Calculating a positional error between the photographing position of the image sensor and the GNSS positioning information at the time of photographing the image by the image sensor; And
Correcting the GNSS positioning information at a position where the landmark stored in the database does not exist in the image photographed by the image sensor using the position error
And correcting the error of the GNSS signal. Image sensor;
A database for storing image information on landmarks and corresponding ground position information;
A photographing position calculating unit for calculating image coordinates of the landmark included in the image photographed by the image sensor and calculating a photographing position of the image sensor from the image coordinates and the ground position information;
(GNSS) positioning information using the photographing position of the image sensor,
The positioning apparatus comprising: 6. The method of claim 5,
And a GNSS module for generating the GNSS positioning information. 6. The method of claim 5,
Wherein the photographing position calculating section calculates the photographing position of the landmark in the image captured by using the image sensor in the same manner as that of the candidate landmark images of the database within a predetermined distance from the corresponding position of the GNSS positioning information, Searches for a landmark image, and analyzes the image coordinates of the landmark image. 6. The method of claim 5,
The photographing position calculating unit calculates the photographing position of the image sensor according to the following equation,

Here, the landmark position information (X, Y, Z) of the landmark, the photographing position S _x , S _y , S _{z of the} image sensor, the image coordinates (x, y) of the landmark, ), The ratio coefficient (s), and the element value (r ₁₁ to r ₃₃ ) of the rotation movement transformation matrix. 6. The method of claim 5,
Wherein the position correcting unit comprises:
A position error between the photographing position of the image sensor and the positioning information of the GNSS module at the time of photographing the image is calculated and the landmark stored in the database in the image photographed by the image sensor And corrects the positioning information of the GNSS module at a position where the GNSS module does not exist.

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