KR20050014463A - Method for estimaing target location in location estimating system - Google Patents

Abstract

PURPOSE: A method for calculating a position of a target position tracking device is provided to obtain an accurate position of a target quickly by obtaining various position information from a GPS(Global Positioning System), a gravity sensor, a laser position measuring instrument and a compass. CONSTITUTION: Information received from a GPS(Global Positioning System) is accumulated to calculate horizontal/vertical positions of a user. An orientation angle of a laser distance detector is calculated by an orientation angle sensor. Two latitude angle measurers calculate latitude of a direction normal to the orientation angle of the laser distance detector. A position of a target is calculated by using the laser distance detector.

Description

Method for calculating the location of the target location tracking device {Method for estimaing target location in location estimating system}

The present invention relates to a method for calculating the position of a target position tracking device to observe the position of the target to calculate the coordinates of the target, and more particularly, to determine the position by the GPS system, the horizontal deviation angle of the device by the gravity sensor The present invention relates to a method for calculating a position of a target position tracking device configured to calculate a target position by combining measurement, azimuth measurement function using a compass and distance measurement using a laser range finder.

Recently, various location tracking devices using GPS systems have been developed and widely used in civil and defense fields. However, the GPS system is generally equipped with a GPS receiver to calculate the position and speed of the user using the navigation data received from the satellite, or move in consideration of the propagation time while communicating with a mobile terminal with a base station equipped with a GPS receiver. The location of the terminal is tracked. These location tracking devices are equipped with a GPS receiver on the target itself, or can be a location tracking system only by sending and receiving information through communication of the target.

However, since the artillery cannot communicate with enemy targets in the field, when the artillery fires, it receives the enemy's position on the map from the observer and fires the artillery by measuring the enemy's position and allies' positions, and measuring the distance. If the fired shell does not hit the enemy, it will be re-corrected and subjected to trial and error until it comes out of the effective shell, which is not only inconvenient and inaccurate due to manual labor but also requires highly skilled personnel. In particular, there is a problem in that it takes a relatively long time, especially in the situation of fast accuracy.

The present invention has been invented in view of the above-described circumstances. In order to obtain the position of a target observed by an observer, the magnetic position check using a GPS receiver, the magnetic north azimuth angle obtained by a compass, and two perpendicularly installed directions When a target position tracking device is developed, which is configured to accurately calculate the position value of the target using two elevation values obtained by the gravity sensor and the distance value to the target measured by the laser range finder, it is applied to the device. The purpose is to provide a method for calculating the target position.

The target position tracking device used to realize the above object comprises: a GPS positioning device that receives navigation data from a GPS satellite and outputs its own vertical / horizontal position data; An azimuth sensor capable of compensating for the distortion of the magnetic north angle measured by the surrounding metal component in the field by using an electronic compass and immediately storing the data in a data format; Elevation sensor consisting of two elevation sensors for measuring the front elevation and the perpendicular elevation facing the laser rangefinder; A laser range finder for measuring a distance to a target by using a time difference between the time of firing the laser and the reflected time; Compute the position of the target from the input information from the GPS positioning device, azimuth sensor, elevation sensor, laser range finder, accumulate GPS information to increase the position accuracy, and correct the error of the azimuth sensor, The position information includes a position calculator having a function of obtaining a straight line directed by the laser range finder using the elevation information input from the sensor to calculate the position information of the observed target.

In addition, the calculated position information of the target is characterized in that it further comprises a wireless transmitter to be transmitted using an embedded modem after the MSK modulation after the encryption and the error recovery code is added.

In addition, the wireless transmission modem is characterized in that the 2400 BPS, MSK modulation type.

In addition, the laser range finder is characterized in that the aiming scope, such as a general sight, infrared / thermal scope.

On the other hand, the target position calculation method according to the present invention, calculating the horizontal / vertical position by continuously accumulating the information collected from the GPS in the GPS positioning device, the azimuth angle directed by the laser range finder by the azimuth sensor Comprising the step of calculating the elevation angle of the direction perpendicular to the direction the laser rangefinder is directed by the two elevation measuring device and calculating the position of the target of the distance measured by the laser rangefinder.

1 is a block diagram according to the present invention,

2a to 2d are coordinates for explaining the coordinate conversion method according to the present invention,

<Description of the symbols for the main parts of the drawings>

10-position calculator, 12-GPS positioning device,

14-azimuth sensor, 16-elevation sensor,

18-laser rangefinder, 20-indicator,

22-modem, 24-radio.

Hereinafter, the configuration and operation of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 shows an overall configuration diagram of a device to which the present invention is to be applied. The present invention is not intended for the device according to FIG. 1 but for a calculation method for entering a position calculator in the accompanying drawings.

The GPS positioning device 12 is a device for confirming vertical / horizontal position information. The confirmed position information is transmitted to the position calculator 10 as described below and continues to use the cumulative average to reduce the error. In the embodiment of the present invention, for example, about one minute of information collection is made to ensure accuracy within a few m.

The azimuth sensor 14 uses an electronic compass to immediately collect the distortion of the magnetic north angle measured by the surrounding metal component in the field, store the data in a data format, and compensate for this. The position calculator 10 which receives the azimuth signal from the azimuth sensor 14 basically includes a program for correcting the difference between magnetic north and north according to the current position difference. In order to correct the correction by the main altitude or feature known in advance, the preferred embodiment of the present invention is to maintain the observation error within a few m within the observation distance (about 20km).

Elevation sensor 16 is composed of two elevation sensors for measuring the front elevation and the right-angle elevation facing the laser rangefinder, when using the two elevation sensors, the observer is a device employing the present invention (hereinafter 'invention device) ), There is no need to waste time trying to level itself with gravity. In addition, the position calculator 10 may calculate correct measurement positions even in areas where gravity is distorted, such as at the base of a high mountain, including the difference data between the geoid plane and the ellipsoid plane of the operating area. have.

The laser range finder 18 measures the distance to the target by using the difference between the time at which the laser is fired and the time at which the laser arrives as the most basic part of the invention device for measuring the position of the target.

The position calculator 10 receives information from the GPS positioning device 12, the azimuth sensor 14, the elevation sensor 16, the laser range finder 18, and the like, and calculates the position of the target to display the display device 20. Or it is made of a microprocessor to perform the role of transmitting to the location information application system via the modem (22). To this end, the position calculator 10 accumulates GPS information, including a program for obtaining coordinates of the most basic target, a program for increasing position accuracy, a program for correcting an error of an azimuth sensor, and using elevation information input from two elevation sensors. In addition, a program for calculating the formula of the straight line that the laser range finder aims at is additionally included. The information obtained is encrypted, then subjected to MSK modulation, an error recovery code is added, and transmitted to the radio using the built-in modem.

Modem 22 is a device for modulating the position information of the target calculated by the position calculator 10 to transmit, for example, to an application system located at a remote location. In case of using a P999K radio, 2400 BPS, MSK modulation type may be preferable.

For example, the radio 24 may be usefully used when the observer wants to observe and transmit the location information of the enemy to the artillery unit in a remote location by using the invention device for military use.

When the laser range finder 18 is equipped with various sights 18a such as a general sight and an infrared / thermal sight, the laser range finder 18 can be used in all weather conditions in various environments.

Hereinafter, the position calculation method according to the present invention will be described in detail.

First, a method of obtaining a GPS position average will be described.

The GPS positioning device 12 uses a world geodetic system (WGS-84) -based rectangular coordinate system as a structure for averaging X, Y, and Z, respectively.

The reason why the Cartesian coordinate system is used is that the longitude, latitude, and altitude of three values are different in the longitude and latitude coordinate system. Because. If the three equations are the same, but only X is given to avoid duplicate explanation, for example,

newAveX = (1-a) * oldAveX + a * inputValueX;

inputValueX: New incoming input X value

oldAveX: the previous newAveX value

newAveX: Newly generated mean (not arithmetic mean)

a: A coefficient controlling the degree of influence of the past value on the average. The value defined as 99.5% of the value of the inputValueX value collected up to 10 minutes ago on newAveX.

By applying the above equation to Y and Z in the same way, the magnetic position of the invention device by GPS can be accurately calculated by calculating the average value of X, Y and Z values for magnetic position.

Next, a description will be given of a method for obtaining the nature and position of the angle information input by the azimuth sensor 14 and the elevation sensor 16.

There are three ways to obtain the azimuth value.

First, the most common method is to obtain information from a 3-axis compass built into the system. The value obtained here is magnetic north azimuth angle, and the difference value with North Korea is different according to longitude and latitude. Therefore, first, the value between Dobuk and Magnetic North should be calculated using the position value obtained from the GPS positioning device 12. The following equation is used.

Here, the position of the device is P _{(x, y, z)} , the north-east position is G _{(x, y, z)} : 0,0, z, the magnetic north position is M _{(x, y, z)} , and the origin is O _{(x , y, z)} : 0,0,0, The normal vector of the device-northplane is N _{O (x, y, z), and} the normal vector of the device-northeast plane is N _{G (x, y, z)} In addition, obtain a vector heading toward the center of the earth from the current position and a vector heading toward the magnetic north (the position of magnetic north should be corrected every year since the position of magnetic north always changes). Find the normal vector based on the location of the device.

=

=

The angle between the two normals is obtained by scalar multiplying two normal vectors starting from the position of the invention device.

Second, there is a way to find the Dobuk azimuth angle from the known point. This method is much more accurate than the information obtained from the three-axis compass mounted on the inventive device. The observer selects a feature that can be identified at the current location, then aims the feature through the sight and inputs the coordinates of the feature in the input window. At this time, the location calculator 10, which is an embedded processor, calculates and sets the azimuth angle of the feature currently being aimed by using its location and the location information of the relative feature obtained from the GPS positioning device 12. Calculation of this value is, firstly, the position value of the magnetic north in the above equation as a difference value between the position of the invention device itself and the plane including the known point position and origin, and the position of the device and the plane including the dobuk position and origin. Is obtained by substituting for the position value of the known point.

In terms of the normal vector starting from the position of the invention device formed by the plane including the position of the known point, the azimuth value is the angle substituted into

Becomes

Third, the method using the Inertial Navigation System (INS) is difficult to use during normal operation (during combat operation) .If the azimuth angle between the INS and the invention device is exactly matched, and then measured for several hours using the INS, accurate As a method of setting the north of the invention device by using this generated principle, it is a method for removing the intrinsic error component of the three-axis compass built in the invention device, and is mainly used in a factory producing the invention device.

In a preferred embodiment of the present invention, a calculation is not required as a method of directly obtaining an angle obtained by a formula in the first and second methods.

Next, a method of obtaining elevation is described.

Elevation requires elevation in the direction the sight is aimed at and elevation in the perpendicular direction. Orientation direction elevation has a direct effect and the elevation direction has a relatively small effect. If the device of the present invention is installed exactly horizontally on gravity, the elevation component in the right direction always becomes "0" and does not affect it. Do not. However, the reason for adding the vertical elevation component is to free the equipment operation environment by not requiring the observer to operate horizontally to operate the observation equipment.

The method for obtaining the position of the target will be described.

First, the abbreviations are defined as follows to clarify the calculation. The alphabetic characters in parentheses indicate the meaning of the subscript.

φ _NA : North-Azimuth

θ _ND : North-Declination of the north direction of the angle formed by the azimuth plane of the invention device with the earth's gravity

θ _WD : West-Declination perpendicular to the west of the angle formed by the azimuthal plane of the invention device with the earth's gravity

θ _AD : High angle in the direction of aiming in the azimuth plane of the invention device (with gravity sensor coupled to sight, Aiming Declination)

θ _OAD : Orthogonal Aiming Declination in the direction perpendicular to the right side when looking at the invention device from the direction in the azimuth plane of the invention device

θ _E : The angle of rotation to the east in a straight line from the earth's center through the equatorial longitude “0” degrees from the earth's center

φ _N : angle in the north direction from the equator plane

θ _SNA : Setting North Azimuth when looking at a specific area through sight

θ _SWA : Setting West Azimuth of another coordinate axis at right 90 degrees when looking at the coordinate system from a particular feature in θ _SNA .

r: Earth's radius (about 6370 km). This part can be replaced by the radius from the cut through the anode in the WGS-84 ellipsoid to the surface of the ellipsoid ellipsoid.

R: Distance measured by laser range finder

A method of converting a coordinate system of the invention apparatus placed arbitrarily into a coordinate system perpendicular to the earth's gravity and having the north-north direction as one axis will be described.

First, the instantaneous values θ _AD and θ _OAD , which are obtained from the built-in gravity sensor, are converted into angles θ _ND and θ _WD at right angles to each other in the exact coincidence direction. This action is set through the input window at the initial azimuth setting.

That is, the θ _AD and θ _OAD are both angles at the time of setting the azimuth angle in the stationary process of the first invention and all subsequent values are values at the time of actual measurement.

For example, the angles at which the known feature at a particular location is θ _SNA and θ _SWA, and the elevations at that time are θ _AD and θ _OAD , respectively.

1) When 0 ≤ 1600 mil (90 degrees) (6400mil = 2 π)

Referring to FIG. 2A, θ _ND is The azimuthal variation of as a comparison that indicates whether the altitude has changed angle θ _AD ingot much when the azimuth θ _SNA changes to -θ _SNA to a situation in which changes to π-θ θ _{AD OAD} in a ratio based on a formula.

Where θ _HX means (High angle X) and means only the change value

here Because of

θ _WD is It is a comparative equation that shows how much the elevation angle θ _OAD changed when the azimuth angle θ _SWA changed to −θ _SNA as a reference ratio based on the situation where the elevation angle changed from θ _OAD to θ _AD .

here Because of

2) When 1600 ≤ 3200 mil (180 degrees)

Referring to FIG. 2B, θ _ND is The azimuthal variation of as much as, the elevation of π-θ _AD much when altitude is changed to π-θ _AD π- _SNA θ of the azimuth θ π- _SNA to the situation with reference to the rate of change in the π-θ _OAD It is a comparison equation that indicates whether it has changed.

here Because of

θ _WD is The azimuthal variation of as much as, the elevation in the azimuth θ _SNA to the changing conditions in π- θ from θ _{AD AD} with the reference ratio It is a comparative equation that shows how much the elevation, θ _AD , changes by.

here Because of

3) When 3200 ≤ 4800 mil (270 degrees)

Referring to FIG. 2C, θ _ND is By changing the azimuth angle by π-θ _AD from π-θ _AD to θ _OAD as a reference ratio, how much the elevation angle of π-θ _AD changed when the azimuth angle π-θ _SNA changed from θ _SNA -π It is a comparative formula.

here Because of

θ _WD is The azimuthal variation of as much as, the elevation in the π- θ _SNA azimuth to the reference for changing conditions in π- θ _OAD ratio in π- θ _AD It is a comparative equation that shows how much the elevation of π-θ _AD is changed by.

here Because of

4) When 4800 ≤6400 mil (360 degrees)

Referring to FIG. 2D, θ _ND is A comparison formula indicates whether the change in the azimuth angle as, the elevation of the elevation θ _AD has changed much when the azimuth angle θ changes to _SNA 2π- θ _SNA to a situation in which changes to θ in the θ _{AD OAD} as a reference ratio.

here Because of

θ _WD is Azimuth angle with θ _SNA -π as the reference ratio, with the change of the azimuth angle from π-θ _OAD to θ _OAD It is a comparative equation that shows how much the elevation of π-θ _AD is changed by.

here Because of

Using θ _ND and θ _WD obtained as described above, conversion of the coordinate system of the invention device to the earth coordinate system is completed as follows.

First, a conversion equation of a coordinate system having an XY plane perpendicular to gravity is obtained at a position represented by φ _N (latitude), θ _E (longitude), and h (altitude) measured by the GPS positioning device 12. . Where X is the direction of true east at that location, Y is the north direction at that location, Z is the altitude, r is the radius of the earth (approximately 6370 km), and r 'is the point projected from the Earth's midpoint when projected to the equator plane at that location. The distance to each is shown.

Because of

Over , , The value is the coordinate value where the invention device is located in the geostationary coordinate system.

= A

The equation obtained above is the conversion equation between the earth coordinate system and the earth system coordinate system. However, the inventive device is not horizontal to the earth's surface and must be converted again. The equation is as follows.

Coordinate transformation of the coordinate system of the invention apparatus is completed by the above equation.

Over , , The value is the target coordinate value in the invention reference frame.

Based on the above equation, the coordinate value of the actual target position is obtained by substituting the values of A, B, and C in the equation below.

As described above, the present invention continuously accumulates the information collected from the GPS to obtain an accurate magnetic position, and then quickly and accurately using the azimuth, elevation, and distance information to the target input from the azimuth sensor, the elevation sensor, and the laser range finder. It is effective to find the position of the target in the earth coordinate system.

Claims (4)

Calculating the horizontal / vertical position by continuously accumulating and averaging information collected from the GPS in the GPS positioning device, calculating an azimuth angle directed by the laser range finder by the azimuth sensor, and laser distance by the two elevation measuring instruments And calculating a position of the target whose distance is measured by a laser range finder after calculating the elevation of the direction perpendicular to the direction in which the measuring device is directed. The method of claim 1, wherein the calculating of the azimuth angle includes one's own position, magnetic north position, and earth's center point by using its position calculated by the GPS positioning device and an azimuth value calculated by the azimuth sensor. Assume the plane, another plane including its own location, the North-Eastern location (the North Pole), and the Earth's midpoint, find the normal vectors of the two planes starting from its location, and then use the scalar product of the two vectors to And azimuth angle difference between the magnetic north and the magnetic north). The method according to claim 1, wherein the position and the position of the target are known using the coordinate value of the feature knowing the coordinates, the azimuth value based on the device support frame, and the own position information calculated by the GPS positioning device. A plane containing the feature's position and the earth's center point, and another plane containing its own location, the North Pole position (the North Pole), and the earth's center point are assumed, and the normal vectors of the two planes starting from its position are obtained. A method for calculating the position of a target position tracking device that accurately calculates an azimuth by obtaining an actual difference between an azimuth aimed at an aiming angle and a north angle using a scalar product of two vectors, and compensating this value by subtracting an azimuth value based on a device support frame. The method of claim 1, wherein the step of calculating the position of the target includes first converting the counterpart position obtained from the device coordinate system into angle and distance information, and then converting the coordinate into a coordinate system having a horizontal axis of gravity and an arctic axis. And calculating the position of the target by converting the coordinates into actual coordinates.