KR100571120B1 - Three dimentional survey system which use the laser apparatus - Google Patents

Abstract

The present invention relates to a three-dimensional positioning system using a laser device, GPS for measuring the exact position irrespective of the stationary or moving object; An INS that measures the rotational angular velocity and the linear acceleration of the vehicle by a gyroscope and an accelerometer to provide current position, velocity, and attitude information of the vehicle; A laser device for measuring an elapsed time of returning the laser wave to the object and converting the distance into a distance; And calculating an external facial expression element based on the position and attitude information of the aircraft measured through the GPS and the INS, and calculating three-dimensional coordinates of the object based on the distance information measured by the laser device and the external facial expression element. computer; Characterized in that it comprises a.

According to the present invention, by using a laser wave directly from the indirect method as in the conventional aerial photographs, it does not go through a complicated process, thereby reducing the cost and time of the result calculation, as well as minimizing the occurrence of errors, the height of the forest terrain In addition, it has the effect of collecting high output three-dimensional position of the urban feature, and accurately generating DSM (Digital Surface Model) and DEM (Digital Elevation Model), which are the core of spatial geographic information.

GPS, INS, Kalman Filtering, External Expression

Description

Three-dimensional positioning system using a laser device {Three dimentional survey system which use the laser apparatus}

1 is a block diagram of a three-dimensional positioning system according to an embodiment of the present invention.

2 illustrates the components of a GPS in accordance with an embodiment of the present invention.

3 is a view showing a principle for measuring the position of the object using the GPS according to an embodiment of the present invention.

4 is a diagram illustrating a principle of measuring a relative position of an unknown point with respect to a known point using GPS according to an embodiment of the present invention.

5 is a view showing a model for converting the ground coordinates to three-dimensional local coordinates according to an embodiment of the present invention.

6 illustrates the components of an INS in accordance with one embodiment of the present invention.

7 is a block diagram of H-GPS (Hybrid GPS) incorporating GPS and INS according to an embodiment of the present invention.

Figure 8 is a block diagram showing a weak coupling scheme in H-GPS according to an embodiment of the present invention.

9 is a block diagram showing a strong coupling scheme in H-GPS according to an embodiment of the present invention.

10 is a view showing a diffusion angle of a laser wave according to an embodiment of the present invention.

11 is a view showing scanning of a laser wave using a reflecting mirror according to an embodiment of the present invention.

12 is a flow chart of onboard aerial sensor data in accordance with an embodiment of the present invention.

13 is a data processing diagram for obtaining a three-dimensional coordinate value according to an embodiment of the present invention.

The present invention is a three-dimensional positioning system, and more specifically, using a laser device for surveying three-dimensional coordinates of the ground feature by mounting a GPS, inertial navigation (INS) and a laser device on the aircraft A dimensional positioning system.

In relation to the conventional three-dimensional positioning system, a number of applications have been filed in addition to the Republic of Korea Patent Publication No. 2003-0005749 'three-dimensional position measuring apparatus and method thereof (hereinafter referred to as' prior patent').

The prior patent discloses obtaining optical image information for each of the objects from each of a plurality of digital cameras attached to a conveying means, processing each of the collected images as an electrical signal, and processing each of the processed signals. Storing the image; cutting the still image from each of the stored signals; subdividing the still image into left and right still images for each frame; and using a digital photogrammetry technique, And extracting and matching features of the right still image, determining external markers of the target objects using the matched image, and using the determined external markers to determine three-dimensional ground coordinates of the target targets. The above ground coordinates are converted into local coordinates by using a step of determining and a coordinate transformation algorithm, respectively. The introduction of an inertial navigation system and a positioning system using artificial satellites in each of the conversion as a parameter corresponding to the object to the local coordinates, and a step of databasing the image information.

However, the prior patent has a problem that takes a lot of time and cost, such as image processing, ground control point surveying, printing, drawing using a satellite image.

In addition, since the prior patent works in several steps, there is a lot of error occurs, and there is a problem that it is difficult to calculate the exact elevation for buildings in mountainous areas and downtown.

An object of the present invention is to solve the above problems, and to provide a system for displaying three-dimensional results using a laser device, GPS and INS without going through a complicated process.

Another object of the present invention is to provide a system for minimizing the occurrence of errors by directly processing using a laser device and GPS and INS, and measuring three-dimensional coordinates of ground objects by linking the position and attitude information of the aircraft. .

The present invention for achieving the above object relates to a three-dimensional positioning system using a laser device, GPS for measuring the exact position irrespective of the stationary or moving of the object; An INS that measures the rotational angular velocity and the linear acceleration of the vehicle by a gyroscope and an accelerometer to provide current position, velocity, and attitude information of the vehicle; A laser device for measuring an elapsed time of returning the laser wave to the object and converting the distance into a distance; And calculating an external facial expression element based on the position and attitude information of the aircraft measured through the GPS and the INS, and calculating three-dimensional coordinates of the object based on the distance information measured by the laser device and the external facial expression element. computer; Characterized in that it comprises a.

And preferably, the computer integrates the GPS and INS information by Kalman filtering to calculate an external facial expression for the point at which the laser wave was fired.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

Equipment configuration of the three-dimensional positioning system according to an embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1, the three-dimensional positioning system includes a GPS 10, an INS 20, a computer 30, and a laser device 40.

The GPS 10 is an automatic satellite positioning system, which can be referred to as a global positioning system, and performs a function of measuring an accurate position regardless of a stationary or moving object.

The INS 20 measures the rotational angular velocity and linear acceleration of the vehicle by means of a gyroscope and an accelerometer called an inertial sensor and uses these outputs to provide the vehicle's current position, velocity and attitude information with respect to the reference navigation coordinate system without external assistance. It performs the function.

The computer 30 performs a function of receiving and storing signals from the GPS, the INS, and the sensors of the laser devices during the flight.

The laser device 40 measures the elapsed time that the laser wave shot from the aircraft has a very short wavelength and returns to the ground object, and converts the time into a distance by using the formula (speed of laser x elapsed time) / 2. It performs the function.

2 is a diagram illustrating components of a GPS according to an embodiment of the present invention.

As shown in FIG. 2, the GPS is composed of a space part 50, a control part 60, and a user part 70.

The space portion 50 is composed of GPS satellites that continuously transmit navigation messages required for position calculation to a user through a carrier wave. The carrier is transmitted to the user in two frequencies L1 (1575.42MHz) and L2 (1227.6MHz) in the L band.

There are a total of 24 GPS satellites, three of which are configured as reserve satellites. The satellite is located about 20,200 km above the Earth's surface, and the satellite's orbit has a total of six orbits at the equator and 55 ° tilt, with four to five satellites placed on each orbit, with an orbital period of 11 hours. It is spinning around the earth twice a day for 58 minutes. Each satellite is equipped with two cesium atomic clocks and two rubidium atomic clocks.

The control part 60 tracks and monitors the GPS satellites through various control stations widely distributed around the world, estimates the position of the satellites as accurately as possible, and transmits various correction information to the satellites. As part of the transmission to the user continuously.

The user portion 70 is essentially provided with one or more receivers for receiving the GPS satellite signals and calculating the position, and is composed of various devices developed to achieve each specific purpose by applying this.

GPS positioning principle is briefly described as follows.

GPS receives the radio waves from satellites that know the exact location by tracked orbit, and measures the time of arrival of the satellites from the satellites to determine the spatial location of the viewpoints.

GPS satellites have an atomic clock, so if the clock on the satellite and the clock on the receiver are exactly the same, the distance from the three satellites can determine the three-dimensional position. Atomic clocks on GPS satellites are very expensive, and receivers use inexpensive, relatively inexpensive clocks, and receive radio waves from four satellites to eliminate the unknown time difference between satellite and receiver time.

)로 이루어지는 총 4개의 미지량을 결정해야 하는데, 이를 해결하기 위해 최소한 4개 이상의 위성을 확보하여야 한다.In order to determine the three-dimensional position of GPS, three position unknowns (X, Y, Z) and one clock error unknown for satellite and receiver (

A total of four unknowns should be determined, which requires at least four satellites to resolve.

From the above-described positioning principle, the earth center to the station is a vector from the earth center to the satellite (U _i ) obtained through the satellite signal and the distance vector (r _i ) from the receiver to the satellite received from the satellite signal from the satellite signal. Calculate the position vector of R _p .

3 is a view showing a principle for measuring the position of the object using GPS according to an embodiment of the present invention.

As shown in FIG. 3, the distance from four satellites 80, 90, 100, and 110 to a point P on the earth is simultaneously observed to determine the coordinates of point P (Xp, Yp, Zp). ) Can be obtained.

That is, general formula

으로부터

From

Where r _i : distance to satellite and station r _i = V × Δt _i (V: Propagation Speed, Δt _i: Propagation Time)

X _i , Y _i , Z _i : three-dimensional position of the satellite

X _n , Y _n , Z _n : the position of the station to find

: 위성과 수신기의 시계오차가 얻어지고, 이것으로부터 측점 P의 좌표(X,Y,Z)를 간단히 계산할 수 있다.

The clock error of the satellite and the receiver is obtained, and the coordinates (X, Y, Z) of the station P can be simply calculated from this.

On the other hand, the fifth dimension of positioning by GPS includes the stability of the satellite atomic clock, the accuracy of the predicted satellite orbit, the propagation delay of the ionosphere, the propagation delay of the troposphere, the noise of the receiver, and the number of channels of the receiver. Generally known accuracy is about 100m when using C / A code and about 10m when using P code for absolute position measured by one receiver. and the error occurs ¹⁰ will have a high degree of accuracy ^6.

4 is a diagram illustrating a principle of measuring a relative position of an unknown point with respect to a known point using GPS according to an embodiment of the present invention.

GPS positioning methods include one-point positioning using one receiver and relative positioning using two or more receivers.

As shown in FIG. 4, relative positioning is a method of measuring a difference in radio wave arrival time by receiving a carrier wave transmitted from a satellite at a plurality of receivers and measuring a phase of a carrier wave or a code. Find the position by obtaining the vector to the point where we want to know the position, install the receiver at the known point, and calculate the position by comparing and analyzing the satellite information received from both the receiver and the unknown point.

One-point positioning is mainly used for the positioning of high-speed moving objects such as automobiles, aircrafts and satellites, and for relatively low positional accuracy such as sea position.

5 is a view showing a model for converting the ground coordinates to three-dimensional local coordinates according to an embodiment of the present invention.

Coordinate transformations are the most fundamental part of mutual and absolute representations of real-time survey systems, and the results obtained from coordinates on the WGS-84 coordinate system need to be converted to various coordinates.

The global coordinate transformation is described in detail as follows.

The result by GPS is represented by the value on the WGS-84 ellipsoid. The latitude and longitude elevation coordinates for any one point are expressed in equation (A), (B), (C) on a three-dimensional rectangular coordinate system.

X = (N + H) cosψ cosλ ..... (A)

Y = (N + H) cosψ sinλ ..... (B)

Z = {N (1-e ² ) + H} sinλ ..... (C)

Here, e ² = (a ² -b ² ) / a ² , a: long radius of the ellipsoid, b: short radius of the ellipsoid.

: 모유선의 곡률반경이다.

: The radius of curvature of the mother wire.

In contrast, the three-dimensional rectangular coordinates of a point are converted into longitude and latitude coordinate systems through equations (D), (E), and (F).

..... (D)

..... (D)

..... (E)

..... (E)

..... (F)

..... (F)

here,

(e ') ² = (a ² -b ² ) / b ² ,

Projection conversion of the WGS-84 to the Bessel ellipsoid used in South Korea derives the deviations of the geodesic coordinate components of the WGS-84 and Bessel coordinates for the satellite observation points on the two reference systems from the Molodensky transformation equation and corrects them. Means to perform the conversion. The equation for calculating the amount of deviation of geodetic coordinate components between two different ellipsoids is shown in equations (G), (H) and (I).

..... (G)

..... (G)

..... (H)

..... (H)

..... (I)

..... (I)

Here, Δψ, Δλ, ΔH are deviations of the geodetic coordinate components between the input ellipsoid and the transformed ellipsoid, and the output-input unit is seconds.

ΔX, ΔY, ΔZ: Ellipsoid origin shift amount of input ellipsoid and transformed ellipsoid

a: long radius of the input ellipsoid

f: flattening of input ellipsoid

Δa, Δf: Difference between input ellipsoid and transform ellipsoid parameters

e: ecentricity

e ² : 2f-f ²

Plane Inspector of the plane rectangular coordinate origin in order to replace the orthogonal coordinate system by latitude and longitude coordinate system also coordinates (λ _0, ψ _0), the line scale factor S ₀ = flat Cartesian coordinates at the time spent to ^{0.9999 (X N, Y E)} , the meridian and milk, If the radius of curvature of the line as each of R _1, N _1, to obtain points of longitude λ, ψ latitude and true north azimuth (or meridional aberrations) γ is given by the formula (J), (K), (L).

... (J)

... (J)

... (K)

... (K)

... (L)

... (L)

Where ρ = 206264.806247 ″, η ₁ = e ' ² cos ² ψ ₁ (e' ² : Second eccentricity),

ψ ₁ : The latitude of the foot of the waterline at the meridian passing through the coordinate origin at the point to be found.

Given the estimated value of ψ ₁ and ψ _n , obtain Bψ from it or calculate ψ _{n + 1} . This computation ψ _{n + 1} - is the ψ _{n + 1} at that time to ψ ₁ is repeated until a satisfactory ^{_{5 - ψ n <2 "×}} 10.

..... (M)

..... (M)

B ψ = length of the meridian arc from the equator to ψ ₁ , the (X ^N , Y ^E ) coordinates at any point in the latitude and longitude coordinates (λ, ψ) Obtained from the fields

로 놓으면

If you put it

..... (N)

..... (N)

..... (O) 이다.

..... (O).

here,

Next, we look at coordinate transformation using 7-parameters.

The 7-Parameters Method is a method of performing a transformation between two different Cartesian coordinate systems by calculating seven transform parameters using the least squares method.

As illustrated in FIG. 5, a conversion equation between the coordinate system X _GP represented by the coordinates to be converted and the coordinate system X _th represented by the coordinates to be converted may be configured as in Equation (P) using a Helmert transformation.

Α ₁ , α ₂ and α ₃ represent rotations in the X-axis, Y-axis, and Z-axis directions, respectively.

X _GP = S.R.X _th + Δ ..... (P)

Where X _GP = [X _{GP ,} Y _{GP ,} Z _GP ] ^T , X _th = [X _th , Y _th , Z _th ] ^T , Δ is the amount of parallel movement of the origin of two coordinate systems, equal to [ΔXΔYΔZ] ^T , and R Is the rotation matrix between two coordinate systems. Formula (P) is specifically shown as Formula (Q).

..... (Q)

..... (Q)

Where X _GP , Y _GP , Z _GP : transformed coordinates,

X _th , Y _th , Z _th : Coordinates to convert

S: scale factor

γ 11, γ 12,..., γ 33: rotation matrix coefficient

ΔX, ΔY, ΔZ: The amount of parallel movement.

In addition, the components of the rotation matrix R are the same as in the formula (R).

..... (R)

..... (R)

Here, ω, φ, and x denote rotation angles on the X, Y, and Z axes, and the rotation matrix is a square matrix, so that R · R ^T = 1.

F (X) = _{S.R.X th} + ΔX-X _GP = 0 ..... (S)

Equation (S) is a nonlinear function, so linearize it using the Taylor series and take up to the first term to form a linearized equation as shown in equation (T).

..... (T)

..... (T)

..... (U)

..... (U)

X ₀ in formula (T) Is the initial approximation of the 7-parameter and dX is the correction for X ₀ . X is also a 7-parameter. The conditional equation is constructed using equation (U) and expressed as a determinant.

AV + BΔ + f = 0 ..... (V)

Where A = I, V = [V _th V _GP ] ^T ,

Δ = [ΔωΔφΔxΔX ₀ ΔY ₀ ΔZ ₀ ] ^T

Δω, Δφ, Δx: Correction amount for rotating element

ΔX _{0 ,} ΔY _{0 ,} ΔZ ₀ : Correction amount for parallel movement.

For I points, assuming the unit weight ratio (P = I) and interpreting equation (V), the correction amount of the seven transform elements can be calculated.

Δ = [Σ (B ^T B _i )] ^-1 [Σ (B ^T F _i )] ..... (W)

In addition, the cofactor matrix Qc is configured as follows.

Qc = A ^T PA = A ^T A = (1 + S ₀ ² ) I

In addition, since matrix Q _dd is an inverse of the matrix of the arguments, it is the same as equation (X).

Q _dd = Q _c ^-1 = (1 + S ₀ ² ) [Σ (B _i ^T B _i )] ^-1 ..... (X)

Therefore, knowing the seven conversion parameters ΔX, ΔY, ΔZ, ω, φ, x, S can transform the coordinates on two different coordinate systems.

6 is a view showing the components of the INS according to an embodiment of the present invention.

As shown in FIG. 6, the INS is composed of a sensor unit 21 consisting of a gyroscope for measuring the rotational angular velocity of the antibody, an accelerometer for measuring the linear acceleration, and a navigation computer unit 22 for performing a navigation program.

The gyroscope is the most important sensor that determines the performance of the INS. It is the object that sees the rotation of the earth and is commonly called the gyro. The gyro may include a rotary gyro using precession, an oscillating gyro using coliolihim, and an optical gyro using a sagnac effect.

The gyro has a structure in which a stable support (Gimbal) supports a rotor that is rotating at a high speed about a rotation axis. A gyro supported by a stable support around two orthogonal axes is called a two-axis degree of freedom gyro, and a gyro equipped with a rotor that does not have a torsional moment due to friction and imbalance, is called a free gyro around two axes. . In addition to the rotation axis, the one-axis degree of freedom gyro has one output shaft and one input shaft, and the three axes are perpendicular to each other.

Vibration gyro has the advantage of long life and short preparation time for operation because there is no rotor, but has a disadvantage of large lift by temperature.

The optical gyro uses the Signac effect, which represents the path difference that occurs when the segmented rays converge at a slight time difference as the circular path rotates.

The refractive index of the optical path is assumed to be 1. In the case where the gyro rotates at an angular velocity ω, the time difference Δt required for the two lights incident at one point to rotate one turn in the opposite direction along the circular optical path is represented by equation (Y).

Δt = t _cw -t _ccw = 4πR ² ω / (C ² -R ² ω ² ) ..... (Y)

Where C is the speed of light and C >> Rω. S is the area surrounded by the circular light path. The optical path difference ΔL using Δt of formula (Y) is the same as that of formula (Z).

ΔL = CΔt = 4S / Cω ..... (Z)

An accelerometer is a device that observes the specific force required to accelerate unit mass. It uses the inertia of an object to observe the acceleration of a payload equipped with an accelerometer.

The accelerometer consists of an integrated gyro accelerometer with an integrated gyro, an experimental mass body accelerometer using a test object mounted in a small friction box, an oscillating string accelerometer using two thin metal tapes, and an optical fiber accelerometer using an optical fiber.

Integral gyro accelerometers use the phenomenon that the torsional moment around the output axis causes precession around the input axis in a gyro with 1 degree of freedom. The linear acceleration generated along the input axis of the integrated gyro accelerometer generates a torsional moment on the output axis of the rate gyro and precession occurs in a cylinder perpendicular to the input axis of the gyro.

The experimental mass accelerometer is a small mass that moves freely from side to side in a tube and is connected to a spring that can limit movement and a brake to prevent large swings.

Vibrating string accelerometers monitor acceleration by connecting strings of thin metal tape to the left and right sides of movable objects. The magnet serves to keep the tape at a nominal frequency and to maintain a constant vibration. When the outer box is accelerated along the reaction axis, the moving object generates different tensions so that the two tapes can vibrate with different frequencies, and the acceleration is proportional to the difference in the vibration frequencies of the two tapes.

An optical fiber accelerometer is a device for observing a force that causes acceleration in an object. When acceleration occurs, the frequency of the micro band is generated, and the intensity of optical force is modulated in the optical fiber. Receive.

The gyro keeps the accelerometer fixed in the inertial system, and since the accelerometer does not sense gravity acceleration, it needs a gravitational effect based on the gravitational model to compensate for the deficiencies of the accelerometer. Using a computer and gravity model, gravity can be calculated as a function of position, and position can be obtained by integrating the observed acceleration twice.

Referring to the analysis of the position of the object using the INS as follows.

The navigation method is to adjust the position of the payload to the known mark, to estimate the position using extrapolation from the observed series of speed increase, and to observe the position of the celestial body for a certain time. Position of the mount using astronomical navigation to determine its current position, radio navigation to interpret the position of the object in relation to the time when electromagnetic waves emitted from the transmitter reach the receiver and return to the receiver. There is an inertial navigation that interprets.

Inertial navigation is the process of determining the speed and position of the payload relative to the starting point of the base by observing and integrating the acceleration of the payload. An accelerometer is a device that senses acceleration, and acceleration is a vector quantity with direction and magnitude.

The basic functions of the inertial navigation system are sensing, computing and outputting. Accelerometers and gyros perform sensing and transmit observations such as acceleration and angular rotation to a computer. The computer uses this data to calculate speed, position, posture, rate of change, orientation, and altitude. The output function is to output the appropriate data for the user's purpose.

INS is a navigation system that uses the inertial information from the gyro and accelerometer to determine the position, velocity, and posture of antibodies without external assistance. It provides very accurate navigation solution in a short time, but over time, bias error, initial alignment error Navigation errors increase rapidly due to such factors.

On the other hand, GPS provides accurate navigation solution for a long time because there is no accumulated error over time, but it may be impossible to operate normally due to external disturbance signal.

As described above, since GPS and INS have complementary error characteristics, it is possible to construct a high-precision navigation system by integration.

7 is a block diagram of H-GPS (Hybrid GPS) incorporating GPS and INS according to an embodiment of the present invention.

As shown in FIG. 7, the H-GPS is an inertial measurement unit (IMU) that detects the rotation angle and the traveling distance of the antibody and corrects and outputs the error, and the position, velocity, and posture of the antibody based on these information. Navigation part to calculate the error, Kalman filter to compensate for systematic error and non-systematic error, and GPS receiver to compensate for errors generated in INS during long time measurement. It consists of.

The Kalman filter is an optimal state prediction process applied to dynamic systems that generate random fluctuations. It is an iterative algorithm that estimates the transient state of a linear dynamic system disturbed by Gaussian white noise, and calculates the mean and covariance. The state equations and observation equations for constructing these algorithms are as follows.

X _{k +1} = φ _k X _k + W _k (state equation)

Z _k = H _k X _k + V _k (Observation equation)

Where X _k is the (n × 1) state vector at time t _k .

φ _k : (n × n) transition matrix from time k to k + 1

W _k is a (n × 1) white sequence with a known covariance, the mean of which the constituents are zero, and are not correlated with other variables

Z _k : (M × 1) observation vector at time point t _k

H _k : Vector (m × m) that connects the observation vector and the state vector at time t _k

V _k : (M × 1) observation error with known covariance and not correlated with W _k

The general algorithm of the Kalman filter is as follows.

, 공분산 오차행렬

입력한다.Initialization phase: Enter initial data (predicted value

, Covariance error matrix

Enter it.

Kalman Profit Calculation: Calculate Kalman profit from initial data.

State Vector Update: Update State Vector Estimation Using Observation Vector Z _k

Covariance calculation: Covariance calculation for updated predictions

Forward-looking predictions: future forecasts

The Kalman filter is an algorithm that shows excellent predictive power in future travel time based on irregular data and continuously reduces errors by covariance by using KALMAN GAIN to obtain the observation equation.

8 to 9 are block diagrams of the weak coupling method and the strong coupling method in H-GPS according to one embodiment of the present invention.

H-GPS system is divided into loosely-coupled system and tightly-coupled system according to the degree of coupling between the two systems.

As shown in Fig. 8, the weak coupling scheme includes a GPS receiver with a Kalman filter and has an IMU with 15 to 18 state Kalman Filters, a navigation processor, and a Δθ's, Δν's from the IMU. Contains a navigation equation that transforms the platform's attitude, position, and velocity.

As shown in FIG. 9, the strong coupling method receives pseudo range and satellite orbit information from GPS and performs everything in one navigation processor, and pseudo and pseudo distances of all traceable satellites are performed. Since the rate is used as a measure, integrated navigation is performed even if the number of visible satellites is less than four, without a sudden decrease in performance.

In the present invention, while using the Kolman filtering method of the strong coupling method, GPS and INS are integrated, while accurate position data is measured using GPS, and the amount of rotation and attitude data of each axis of the aircraft is measured using the INS, the aircraft is in flight. Obtain absolute position measurement and attitude information.

10 is a view showing a diffusion angle of a laser wave according to an embodiment of the present invention.

The laser amplifies the light by the induced emission of electromagnetic waves, which means that the electromagnetic waves generated by the induced emission method are amplified to have a large energy.

In order to generate a laser, a mirror (not shown) with different reflectances must be paralleled between special objects called a laser medium and energy is injected into the laser medium. The energy entering the laser medium is mainly strong light or electrical energy, which induces emission within the laser medium. The light generated by the induced emission is gradually increased in energy while reciprocating between the mirrors (not shown), and is transmitted through the mirrors (not shown) when it reaches a certain limit. Lasers can be divided into gas, liquid and solid lasers depending on the state of the laser medium.

As shown in Fig. 10, in the present invention, a solid state laser, Nd: YAG (1064 nm) laser, is used. Nd: YAG lasers enable high energy pulses to be realized at short time intervals, enabling accurate distance measurement, and narrowing the diffusion angle of the laser wave to 0.7 mrad or less, making it possible for small objects on the ground at high altitudes. Distance measurement is possible.

In this embodiment, the diffusion angle of the laser wave is set to 0.7 mrad or less, but the present invention is not limited thereto.

11 is a view showing scanning of a laser wave using a reflection mirror according to an embodiment of the present invention.

As shown in FIG. 11, when the laser device shoots a laser wave on an object on the ground, the laser device scans the laser wave on the object on the ground by using a reflection mirror moving by a predetermined angle φ from side to side.

12 is a flowchart of onboard aerial sensor data according to an embodiment of the present invention.

As shown in FIG. 12, the computer 30 receives signals (S2) and time from the sensors of the GPS 10, the INS 20, and the laser device 40 mounted on the aircraft (S2), and the INS ( 20) and time information of the laser device 40 sensor is stored as a computer time, and then synchronized to the GPS (10) time (S4).

The computer 30 receives the correct aircraft position and attitude information at every moment when a plurality of lasers are fired by using the complementary relationship between the GPS 10 and the INS 20 (S6), and receives the position and attitude of the received aircraft. The information and the range of the laser are stored after the integrated process (S8).

13 is a data processing diagram for obtaining a three-dimensional coordinate value according to an embodiment of the present invention.

As shown in FIG. 13, the computer 30 may store previously stored data and a time point at which the laser wave is fired using the Kalman filtering technique S10 of the GPS 10 and the INS 20 that are strongly coupled. An external facial expression element result is calculated (S12), and the obtained external facial expression element is integrated with distance information of the laser sensor (S14) to calculate a three-dimensional position of the object (S16).

According to the present invention as described above, by using a laser wave directly away from the indirect method, such as the conventional aerial photo, there is an effect of minimizing the occurrence of errors, as well as the cost and time reduction of the result calculation.

In addition, according to the present invention, it is possible to calculate the accurate elevation by collecting a high-power three-dimensional position for the topography of the city as well as the height of the forest topography using a laser device, and the DSM (Digital Surface) which is the core of spatial geographic information It has the effect of accurately creating the Model and Digital Elevation Model.

Claims (2)

In a three-dimensional positioning system, GPS for measuring accurate position regardless of stationary or moving object; An INS that measures the rotational angular velocity and the linear acceleration of the vehicle by a gyroscope and an accelerometer to provide current position, velocity, and attitude information of the vehicle; A laser device for measuring an elapsed time of returning the laser wave to the object and converting the distance into a distance; And The location and attitude information of the aircraft measured using the GPS and the INS are integrated through the Kalman filtering technique. A computer for calculating three-dimensional coordinates of an object based on information and the external facial expression elements; Three-dimensional positioning system using a laser device comprising a. delete

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