KR100898617B1 - Construction method for digital elevation model of area coexisting the ground and water through verification of tin data of lidar and mbes measure value - Google Patents

Abstract

The present invention constructs the digital elevation model data of the land using an air laser survey (LiDAR), and builds the numerical elevation model data of the water depth using a multi-beam echo sounder (MBES), and then measures the LiDAR survey and MBES survey values. By performing interpolation performance verification of TIN interpolation, interpolating numerical elevation model data of different survey values based on numerical data of survey values with higher accuracy, and integrating them, the land part and the depth part coexist together. To build a precise numerical elevation model for

According to the method of the present invention, it is possible to construct a numerical elevation model of a region where the land and the depth co-exist together more quickly and accurately with less manpower. Therefore, by constructing the bottom sediment management system based on the established digital elevation model, it is possible to prevent inadvertent dredging work and establish flood prevention measures in connection with the flood prediction system. Also, the digital elevation model can be used as terrain analysis data using 3D image.

Digital elevation model, aviation laser instrument, multibeam acoustic echo sounder, performance verification

Description

 Construction method for Digital Elevation Model of Area Coexisting the Ground and Water Through through verification of irregular triangular network (TIEN) interpolation performance of LID survey and MBES survey values Verification of TIN Data of LiDAR and MBES Measure Value}

The present invention relates to a method for constructing a digital elevation model of an area where a land part and a depth part coexist, and more specifically, to construct a digital elevation model data of a land part using an air laser survey (LiDAR), and to multi-beam acoustic echo sounder. After constructing the numerical elevation model data of the depth area using (MBES), verifying the random interpolation performance of the LiDAR survey and MBES survey values, and verifying the numerical elevation model data of the survey values with higher accuracy. By interpolating and integrating numerical elevation model data of different survey values as a reference, a method of constructing an accurate numerical elevation model of a region where land and water depths coexist.

Water is an indispensable resource that is indispensable throughout the birth, growth, reproduction, and extinction of all living things, including mankind. While many countries around the world are expected to become water scarce countries, 20% of the world's population (about 1.1 billion people) cannot drink clean water due to the failure of global water resource management policies. In Korea, the annual amount of renewable water resources per capita by country is 130th out of 153 countries. The necessity of water resource management is increasing. In particular, the importance of dam and river management, which will be the main infrastructure for water resource management, is expected to be emphasized. do. In Korea, the average annual rainfall per capita is 2,705㎥, which is only 1/10 of the world average of 26,800㎥. In particular, rainfall is segregated by age, season, and region, and it is a characteristic of mountainous terrain with steep slopes. In normal times, there is a problem in the water supply due to the lack of river water, and unlike the foreign countries with even rainfall throughout the year, the need for river management will continue to increase due to frequent floods and droughts. Therefore, in order to perform the role of rivers properly, the importance of technology for precisely identifying and managing rivers is increasing, and precise river surveying technology, which provides basic data on river conditions, has emerged as an important issue. In the future, river surveying techniques will require greater accuracy, speed, and database, and the technology is expected to evolve.

River surveying is to clarify the situation of rivers when constructing data for hydrological analysis, the number of rivers, and other constructions.These include level surveying, reference surveying, current surveying, water depth surveying, and flow measurement. Work is included. Today's river surveying technology is based on the flat plate and allyid in the field, and after the classic plate surveying step, the base station and the current surveying step by total station, and the lower reference point using the precision global post system (GPS) Surveying, present-day surveys, and bottom-level depth surveying using acoustic echo sounders have been established.

With the development of GPS surveying system, researches on real-time surveying using GPS (Kang Chang-mo 1995), three-dimensional topographical analysis (Shin Sang-chul 2001) and digital terrain model generation (Kang Gil-sun 2004) have been conducted, and river surveying using GPS and total station ( Choi Bo-yong (2007), surveying using GPS and echo sounder (Kim Hyun-ho 2005), etc., are also in progress. The study of surveying technology using a light detection and Ranging (LiDAR) system introduced in Korea in early 2000 was carried out to evaluate the accuracy of aviation LiDAR surveying methods (Lee Yoon-soo 2005, Chang-bok Lee 2006) and the efficiency of aviation LiDAR surveying In addition, research has been carried out in various areas, including aviation LiDAR surveying and performance collection using single beam echo sounder (Oh, Yoon-Seok 2005).

In addition, research using the Multi Beam Echo Sounder (MBES), which was developed for military use in the US Navy and used for precise seabed surveying of seabeds, includes error analysis (Park Yo-Seop 2004) and accuracy improvement (Kim Yeon-su 2005), subsea structures. Research has been carried out in various fields such as Hyung-Keun Park (2007).

In order to maximize the efficiency of new surveying techniques and efficiency in the development of such an extension ratio, researches are being conducted by national institutions, various research groups, schools, etc., but using precision surveying equipment such as GPS, aviation LiDAR, MBES, etc. There have been no surveys of rivers and coastal areas, where the maritime department coexists.

Accordingly, the present inventors construct numerical elevation model data of the land using an air laser survey instrument (LiDAR), and digital elevation model data of the depth portion using a multi-beam acoustic echo sounder (MBES), and then each numerical elevation model We have built a precise numerical elevation model for the region where land and water co-exist.

However, the present inventors confirm the accuracy of the TIN interpolation performance of LiDAR survey values and the TIN interpolation performance of MBES surveys based on the local survey values measured before field integration. And interpolate the digital elevation model (DEM) data of other survey values based on the digital elevation model (DEM) data of the survey value with a TIN interpolation performance that is more consistent with the local survey values. Integrating the model confirmed that it was possible to build a digital elevation model (DEM) with higher accuracy and completed the present invention.

An object of the present invention is to provide a method for constructing a digital elevation model of an area where the land and water depths coexist with improved accuracy and reliability.

In order to achieve the above object, the present invention comprises the steps of (a) surveying the coordinates and altitude by using an aircraft equipped with GPS / INS and LiDAR to the land part of the area where the land part and the depth part coexist together ; (b) surveying coordinates and depths using a vessel to which a DGPS and a multi-beam echo sounder (MBES) are attached to a depth portion of an area where the land portion and the depth portion coexist; (c) converting the LiDAR and MBES measurement values measured in the steps (a) and (b) to the height level; (d) constructing respective digital elevation model (DEM) data based on the LiDAR and MBES survey values converted from the normal elevation in step (c); (e) performing local inspection by selecting an area having a length of at least 50 m and a length of at least 5 m in a region in which a plurality of land and water depths in which the LiDAR survey and the MBES survey are co-existed overlap with each other; step; (f) After performing the interpolation of the irregular triangle network (TIN) of the LiDAR survey values and the interpolation of the random triangle network (TIN) of the MBES survey values, based on the local survey values measured in the field survey in step (e). Respectively checking the accuracy; (g) Determine the equality of the highest and lowest points of each survey value by analyzing the longitudinal and cross-sectional surfaces of the TIN interpolation performance of the LiDAR survey values and the TIN interpolation performance of the MBES survey values. Making; (h) a digital elevation model (DEM) of another survey value based on the digital elevation model (DEM) data of the survey value having a random interpolation (TIN) interpolation performance that is more consistent with the local survey value identified in step (f). ) Interpolating the data; And (i) integrating the digital elevation model (DEM) data of the LiDAR measurement values constructed in step (d) with the digital elevation model (DEM) data of the MBES measurement values interpolated in step (h) based on the Integrating the digital elevation model (DEM) data of the MBES survey values constructed in step d) with the digital elevation model (DEM) data of the LiDAR measurement values interpolated in step (h) based on this, wherein the land and water depths coexist together. How to build a digital elevation model for an area where land and depth coexist by verifying LiDAR survey and MBIN survey's irregular triangular network (TIN) interpolation performance including the step of building a regional digital elevation model (DEM) To provide.

According to the method of the present invention, it is possible to construct a numerical elevation model of a region where the land and the depth co-exist together more quickly and accurately with less manpower. Therefore, by constructing the bottom sediment management system based on the established digital elevation model, it is possible to prevent inadvertent dredging work and establish flood prevention measures in connection with the flood prediction system. Also, the digital elevation model can be used as terrain analysis data using 3D image.

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

Digital elevation model (DEM) refers to data represented by three-dimensional coordinates used to construct geographic information system (GIS), among which digital terrain model (DTM) and digital terrain (DTD) Data) and DTED (Digital Terrain Elevation Data). The digital elevation model is used as basic data for dam, road and railway construction in various civil engineering fields, and also for the construction of transmission towers for the transmission of radio waves through the analysis of visible areas at arbitrary locations and for the proper selection of radar facilities. It is also used for quite a few analysis.

In one aspect, (a) surveying the coordinates and altitude using the aircraft equipped with GPS / INS and LiDAR to the land portion of the area where the land portion and the depth portion coexist; (b) surveying coordinates and depths using a vessel to which a DGPS and a multi-beam echo sounder (MBES) are attached to a depth portion of an area where the land portion and the depth portion coexist; (c) converting the LiDAR and MBES measurement values measured in the steps (a) and (b) to the height level; (d) constructing respective digital elevation model (DEM) data based on the LiDAR and MBES survey values converted from the normal elevation in step (c); (e) performing local inspection by selecting an area having a length of at least 50 m and a length of at least 5 m in a region in which a plurality of land and water depths in which the LiDAR survey and the MBES survey are co-existed overlap with each other; step; (f) After performing the interpolation of the irregular triangle network (TIN) of the LiDAR survey values and the interpolation of the random triangle network (TIN) of the MBES survey values, based on the local survey values measured in the field survey in step (e). Respectively checking the accuracy; (g) Determine the equality of the highest and lowest points of each survey value by analyzing the longitudinal and cross-sectional surfaces of the TIN interpolation performance of the LiDAR survey values and the TIN interpolation performance of the MBES survey values. Making; (h) a digital elevation model (DEM) of another survey value based on the digital elevation model (DEM) data of the survey value having a random interpolation (TIN) interpolation performance that is more consistent with the local survey value identified in step (f). ) Interpolating the data; And (i) integrating the digital elevation model (DEM) data of the LiDAR measurement values constructed in step (d) with the digital elevation model (DEM) data of the MBES measurement values interpolated in step (h) based on this. The land part and the depth part together by integrating the digital elevation model (DEM) data of the MBES survey values constructed in step (d) with the digital elevation model (DEM) data of the LiDAR measurement values interpolated in the step (h). Construct a digital elevation model for the region where the land and water co-exist together through verification of LiDAR survey and irregular triangular network (TIN) interpolation of MBES survey values, including the step of constructing a digital elevation model (DEM) of the coexisting region. It is about how to.

First, in order to construct a numerical elevation model for the area where the land and depth coexist, the coordinates and altitude are measured by using a GPS / INS and a LiDAR-attached aircraft. Survey

Light Detection and Ranging (LiDAR) is equipped with a laser scanner on an aircraft to scan the laser pulses on the ground and observe the arrival time of the reflected laser pulses to calculate the spatial position coordinates of the reflection points. Surveying techniques to extract information about

The LiDAR system consists of a laser scanner, a GPS, and an INS. The laser scanner is further divided into a distance surveying unit and a scanning unit, which are integrated and operated by a control unit. The basic principle of LiDAR's positioning is to determine the three-dimensional X, Y, and Z coordinates of the elevation of the surface by observing the position of the sensor, GPS, and the position of the sensor, and the laser scanner by observing the distance between the sensor and the surface. to be.

LiDAR can now measure a wider area by rotating the mirror attached to the front of the laser sensor, or by scanning the surface using a Palmer scan, fiber scanner, or rotating polygon, and can measure the scan angle, scanning frequency, flight altitude, and flight speed. In addition, the number of measurements per second, etc., determines the density and characteristics of the survey. It can also be equipped with video and survey cameras as ancillary equipment for data integration.

The laser scanner can calculate the distance between the ground surface and the laser scanner by scanning a laser wave having a constant swath width in the form of a pulse, and at this time, it is also possible to adjust the points density. According to the laser scanning method, the laser scanner can be classified into oscillating mirrors, rotating mirrors, nutating mirrors (palmer scan), and optical fiber methods. The general form of scan-line obtained by each method is zigzag-line or parallel-line for oscillating mirrors, parallel-line for rotating mirrors, and elliptical form for nutating mirrors (palmer scan). In the case of optical fiber, it forms a parallel line. Laser scanning is used to acquire the data in the right and left directions of the flight path with the scan angle and the scan width according to the altitude, and the shape of the scanline on the ground is not only the scanning method but also the flight direction and flight speed. Is also affected.

 The position of the plane and the position of the laser are determined as 3D coordinates using DGPS. This requires high-accuracy GPS equipment to be installed on the plane, as well as the installation of a GPS base station.

Laser devices are generally fixed so that they are perpendicular to the ground while the aircraft is flying horizontally. However, laser beams are not always emitted vertically due to various aircraft roll, pitch and yaw changes during flight. Therefore, INS using high-precision gyroscope is used for attitude measurement of aircraft, and this attitude data is used for 3D coordinate determination of LiDAR data.

The area where the land part and the depth part coexist together is an area where the quantity changes with time, and examples thereof include rivers, rivers, reservoirs, dams, and the sea. In other words, rivers, rivers, reservoirs, dams, and the sea may be different from the land or depth zones affected by precipitation, seasonal changes, and artificial factors that affect floods and droughts over time. In the case of the sea, the land and the depths coexist with the repeated high and low tide.

In the present invention, the LiDAR survey is preferably measured when the water level of the depth portion of the area where the land portion and the water depth portion coexists below the average water level. That is, since the LiDAR survey is measured on the land, it is preferable to measure the time when there is little rainfall and when there is no pool or the like that causes the reflection of the LiDAR pulse.

Next, coordinates and depths are surveyed using a ship equipped with a DGPS and a multi-beam echo sounder (MBES) for a depth part of an area where the land part and the depth part coexist.

The MBES survey is preferably measured when the water level of the depth portion of the area where the land part and the depth part coexist together is above the average level. In other words, since the MBES survey is measured at the depth of the water, it is preferable to measure at the time of heavy rainfall.

In the present invention, the multi-beam echo sounder (MBES) is different from the conventional single beam acoustic echo sounder, which emits a fan-shaped sound wave and measures the depth of the depth of 3 to 5 times at the same time to take a picture of the shape of the sea bottom. It is an advanced equipment that can draw the bottom of the sea.

The MBES system is composed of a plurality of sonar transducer arrays. By adjusting the phase difference of each sonar array, a beam having a pointing angle may be generated. In general, when generating sound waves, a fan-shaped beam which is wide in the current direction and a narrow beam width in the bow direction is generated and fired, and when received, multiple beams are received in a direction orthogonal thereto. Observation of the orthogonal time point to measure the inclination distance.

The shallow sea MBES is composed of a transmitter consisting of a projector having a center frequency characteristic of 100 KHz or more, a receiver composed of a hydrophone for receiving a signal reflected from the bottom of the sea and a processing system for signal processing ( It consists of three parts. The waveform of the scanning beam from the sound source is characterized by a constant scanning width (Swath Angle: 90 to 160 °) in the vertical direction with respect to the traveling direction of the irradiation line and the characteristics of a split beam beam (0.5 to 3.0 ° in the bow and stern directions). The transmitter and receiver are designed to show). The signal reflected back from the sea bottom measures the depth of the center point with respect to a certain surface of the scan width at fine time intervals according to the hydrophone arrangement of the receiver. The processing system consists of hardware such as DSP (Digital Signal Processor) board, computer operating device and recording device that digitally converts analog signal.

In the echo sounding method, the sound velocity in seawater changes depending on the state of seawater temperature, salinity, pressure, and the like. That is, the speed of sound is not constant by time and location of water masses, but changes by season, sea area, and depth. To get a more accurate depth, it is important to know the distribution of sound velocity in detail at the location when measuring depth. Sound velocity measurement methods include Bar-Check method, calculation method, and sound velocity measurement method. It is necessary to obtain such correction data by selecting this method depending on the area of conduct of the survey, the degree of sounding, the conditions of the equipment used, and the conditions of data cleanup and performance. In the method of measuring the velocity of a sound, a sound velocity measuring device (SVP) is dropped in water and measured and applied to the MBES, or a sound velocity measuring sensor is attached to a survey ship bottom to measure and apply the velocity in real time.

Next, to correct the error of the LiDAR and MBES measurement values, and to improve the accuracy, the normal elevation conversion is performed. The normal elevation can be calculated by fabricating the geoid model through local surveying in accordance with conventional methods.

When the normal elevation conversion of the LiDAR and MBES measurement values is performed, respective Digital Elevation Model (DEM) data are constructed for the LiDAR and MBES measurement values which have been converted from the normal elevation. The digital elevation model (DEM) data can be constructed using commercially available software. For example, Bentley's Micro Station Ver8.1, Terrasolid's TerraScan and TerraModel can be used to build LiDAR survey DEMs, and Navipac S / W can be used to build MBES survey DEMs.

The digital elevation model (DEM) data of the LiDAR and MBES survey values may be constructed independently after the LiDAR or MBES survey, or may be performed simultaneously after both surveys are completed. That is, in the present invention, the order of constructing the digital elevation model (DEM) data of LiDAR and MBES measurement values may be performed before the integration of the digital elevation model (DEM) data without particular limitation.

Next, among the areas where the land and water depths in which the LiDAR survey and the MBES survey are carried out coexist, the local survey is performed by selecting an area having a length of 50 m or more and a 5 m or more length in which the survey values overlap each other. When the lengths of the horizontal and vertical portions of the overlapping portions are less than the reference, it is determined that the data for the performance verification are not valuable.

The field detection is preferably a total station, it is possible to measure the local survey values, such as coordinates, altitude of the selected area.

In the present invention, after performing the field detection, after performing the triangulation of irregular triangle network (TIN) of LiDAR survey value and the irregular triangle network (TIN) of MBES measurement value based on the field measurement value measured by field inspection, Check the accuracy of each. Therefore, by comparing the local survey value and the LiDAR survey value or by comparing the local survey value and the MBES survey value, it is possible to confirm which of the three survey values is correct.

In general, when there is a bush in the measuring area, irregular TIN is formed by reflecting LiDAR pulses by the bush, and when the measuring area is composed of sand, the topographical change may occur as water enters or falls out.

When the accuracy of the survey values is confirmed, the peaks of the survey values and the cross-sections of the cross-sections and the cross-sections of the irregular triangular network (TIN) interpolation results of the LiDAR survey values and the irregular triangular network (TIN) interpolation results of the MBES survey values are determined. It is desirable to confirm whether or not the lowest point is identical. If you integrate their Digital Elevation Model (DEM) data when the peaks and troughs of each survey value are not the same, the accuracy and reliability of the data will be lower. In the present invention, the step of determining whether or not the highest point and the lowest point of the measurement value may be performed after interpolation of the following digital elevation model (DEM) data.

When the accuracy of the survey values is confirmed, the digital elevation model (DEM) data of the other survey values are based on the digital elevation model (DEM) data of the survey values having a TIN interpolation performance that is more consistent with the local survey values. Interpolate That is, when the survey value having a TIN interpolation result that is more consistent with the local survey value is a LiDAR survey value, the MBES numerical elevation based on the LiDAR numerical elevation model (DEM) data constructed in step (d) MBES numerical model (DEM) constructed in step (d) when interpolating model (DEM) data and the survey value having a random interpolation (TIN) interpolation result that is more consistent with the local survey value is an MBES survey value. ) Interpolate LiDAR numerical elevation model (DEM) data based on the data.

Finally, the digital elevation model (DEM) data of the LiDAR measurement value constructed in step (d) and the digital elevation model (DEM) data of the MBES measurement value interpolated in step (h) are integrated based on the Integrating the digital elevation model (DEM) data of the MBES survey values constructed in step d) with the digital elevation model (DEM) data of the LiDAR measurement values interpolated in step (h) based on this, wherein the land and water depths coexist together. Build a regional digital elevation model (DEM).

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not to be construed as being limited by these examples.

Chungju Multi-purpose Dam Reservoir was selected as the study area for riverbed and bottom survey survey using LiDAR and MBES (see Fig. 1). The Han River basin is located in the central part of the Korean Peninsula, which spans 36 ° 30 'to 38 ° 55' north latitude and 126 ° 24 'to 129 ° 02' longitude. The area of about 160.7km from the confluence of the Han River and the Island River is 200-700m above sea level, which is located in the flat lowlands between most valleys and forms a gradient of about 0.1-0.2m / km. The target area was selected.

Example 1 Aviation LiDAR Data Surveying

1-1. Aviation LiDAR Calibration

LiDAR calibration was performed after the equipment was mounted on the aircraft as an essential process to determine and correct the self-errors of the system and to calculate the exact 3D position coordinates of the terrain. After the installation, the separation distance between each sensor (aviation LiDAR, GPS receiver, INS equipment) was measured using a total station, and the actual flight data of the test site prepared in advance was corrected according to the base coordinates. In addition, the measured value obtained by using the instrument on the ground to obtain the distance information by calculating the constant value of the equipment. 2 is a photograph showing the measurement of the X, Y, Z axis and the separation distance of the system visually, Figure 3 is a photograph showing a monitor screen to obtain the separation distance through the measurement value.

Sensor separation distance values of the calculated equipment are shown in Table 1 below.

TABLE 1

equipment X Y Z GPS 0.208 m 0.002m -1.275m IMU -0.269m 0.207 m -0.004m

As shown in FIG. 4, the system was calibrated through a one-way aviation laser survey in Budang-dong, Cheonan-si, Chungcheongnam-do. The regional selection conditions of Cheonan include relatively flat urban areas and a few hills, making it easy to measure ground control points and level points, and have the optimal conditions for aviation laser survey correction. Factors to adjust the system error through the test field are Pitch, Roll, Scale and Offset.

In order to calculate the correction amount for roll, pitch, and heading, tie point observation was performed for overlapping area. Tie point was observed 30 ~ 50 points per line on road and flat land, not on slope and outside of building. Roll, Pitch, Heading correction amount calculation results are shown in Table 2 below.

TABLE 2

division Roll Pitch Heading Machine Spec (deg) 0.0042 0.0042 0.0194 Standard deviation (deg) ± 0.0018 ± 0.0026 ± 0.0110 Correction value (deg) -0.5458 0.1695 -0.0603

1-2. GPS Ground Station

When using the GPS / INS to conduct aerial LiDAR surveying, the GPS ground reference station operates the GPS data reception at 2Hz intervals from the aircraft's take-off until landing to ensure accurate positioning of the onboard laser scanner. Two points of reference station were installed at a position that can minimize cycle slip within 30 km, and the coordinate values of the ground reference station are shown in Table 3 below.

TABLE 3

point Latitude Hardness Oval height CH00 36 ° 59'59.51472 "N 128 ° 07'45.42431 "E 197.454 m CH01 36 ° 59'12.86334 "N 127 ° 54'34.68149 "E 108.003m

1-3. Aviation LiDAR Surveying

Coordinates and altitudes of the Chungju Dam area (see Table 5) were measured using an aircraft equipped with GPS / INS and an air laser survey instrument (LiDAR).

1-4. Elevation Survey

In order to establish the normal elevation of the aviation LiDAR, an elevation survey was conducted. At this time, the error of the aviation LiDAR was corrected using only the ground surface point of the ground reference point.

Since the calculated three-dimensional point data uses GPS / INS data in the process of processing, the height value is calculated from the ellipsoid height based on the WGS84 ellipsoid. Therefore, geoid model was created and local elevation was calculated from local survey results for conversion to normal elevation value. In order to work smoothly during GPS survey and baseline analysis, ground reference point survey was conducted with GPS equipment that can receive both L1 and L2 (2 frequencies).

The process of surveying the normal height conversion by GPS survey was observed for more than 30 minutes in each session. The data was downloaded from the National Geographic Information Institute, and the network adjustment was performed after combining with the GPS observation data. The normal elevation value was calculated using the ellipsoid height and the elevation deviation as shown in FIG.

The static elevation transformation survey layout was arranged to be evenly distributed in the study area as shown in FIG. 6.

1-5. Data Processing

For DEM construction, the GPS / INS raw data, the most basic data surveyed by aircraft, was converted to GrafNav format as shown in FIG. 7 (a), and in order to convert RAW data into LAS data as shown in FIG. 7 (b). Similarly, ALS PP (ALS Post Processol) was used for IMPORT. Then, the imported RAW data was converted into LAS data in the ALS PP as shown in Fig. 7C.

Then, we generated an irregular triangle network (TIN) from the extracted key points (Model KeyPoint), searched the same height points with TIN, and extracted contour lines with a 1m interval by applying B-spline interpolation. 8 is a diagram illustrating an example of DEM construction through reflection wave extraction and ground classification.

In other words, after preprocessing and postprocessing the LiDAR survey values, Pentudo-Grid, Digital Surface Model (DSM), and Digital Elevation Model (BMS) are available through programs such as Bentley's Micro Station Ver8.1, Terrasolid's TerraScan, and TerraModel. DEM).

9 is a diagram showing the results of the digital elevation model (DEM) fabrication of LiDAR measurement values.

Example 2 MBES Data Surveying

SeaBat 8125 (Reson) was used as the MBES system for the survey of the depth, Trimble's DSM132 was used as the DGPS satellite, and Octans III Surface System was used for the Gyrocompass and Motion Sensor.

2.1 MBES Setting

Octans, DGPS antennas and transducers were installed in the closest position based on the ship's center of gravity for accurate sounding data acquisition. One basic coordinate system (the distance of X, Y, Z) was substituted into Navi-Pac. The fixed offsets installed in the basic coordinate system and survey line of the MBES System are shown in FIG. 10.

TABLE 4

division X Y Z DGPS 0 0 m -2.27 m Octan 0 0.57 m 0 m Transducer 0 0 m 0.27 m

2-2. MBES Calibration

In order to offset the error value according to the alignment state between the Gyro and the Motion Sensor and the MBES transducer in order to reduce the error of the surveying performance, the correction value between the bow direction, the string direction, and the direct direction was calculated and substituted.

2-3. Sound Compensation

Sound Velocity Profiler used Reason's SVP15 and set the sound velocity to be acquired at 0.5m intervals of direct water by dropping directly from the surface. Sound velocity correction was obtained at intervals of about 3 hours after acquiring sound velocity before surveying and at the end of the survey.

2-4. Water level correction

In order to observe the water level for the correction of the depth measurement of Chungju Dam, the observation data is collected by installing temporary test stations to use the basic data by identifying the tidal difference at the three entrances near Chungju Dam Main Dam, Cheongpung Bridge, and Danyang as shown in Table 5 below. Analyze

 TABLE 5

location Utilization reference point Observation period Tide standard Observation instrument Main Dam Entrance Main Dam Level 1 Reference Point 2007.12.28 Level 1 reference point height Pressure checker Near Cheongpung Bridge  No.1047 2007.12.28  No.1047 Reference point height Pressure checker Danyang   No.1041 2007.12.28 No.1041 Reference Point Height Pressure checker

Tide was obtained by using a tester (XR-420-TG, RBR) at intervals of 10 minutes, and the water level difference between the three points was measured by a pressure method.

2-5. Elevation conversion

The peak elevation conversion survey of MBES survey was performed after observing dam level (dam level check by Korea Water Resources Corporation).

2-6. Data Processing

The measured multibeam data was stored as raw data in * .SBD format through a Navi-PAC program and Navi-Scan as shown in FIG. After saving the raw data through the Navi-edit program, a series of correction processes such as level correction, sound speed correction, and depth correction were performed and converted into final results. At this time, the files were converted into X, Y, Z files and NED files according to the necessary purpose, and the grid performance was derived through the Contour program for conversion to DEM, and the three-dimensional representation of the terrain was implemented.

That is, the detailed process of MBES depth surveying first obtains WGS-84 coordinates using a real-time DGPS receiver to determine the sea position of the sounding line, then corrects the position conversion (UTM projection) to TokyoDatum with Navipac S / W. The position of the surveying line in Hangzhou was determined by the linear guide method. Calibration was performed to verify the position of the DGPS, and the DGPS and MBES survey values were processed using Navipac S / W. The measurement value was corrected in real time by checking the sound velocity (Sound Velocity), and the noise was removed from the MBES automation system and the data was automatically processed by the digital continuous output method. The water level was corrected by acquiring the results obtained by real-time tide observation at the site. Next, a digital elevation model (DEM) was fabricated using Navipac S / W.

FIG. 13 is a diagram illustrating a DEM generation process using NaviScan S / W, and FIG. 14 is a diagram showing DEM fabrication performance of MBES measurement values.

Example 3 Verification of Irregular Triangular Interpolation (TIN) Interpolation of LiDAR and MBES Survey Values through On-Site Detection

The overlapping values of the survey values of the regions where multiple land and water depths coexist with LiDAR survey and MBES survey were confirmed. As a result, the survey values of 110m horizontally and 10m vertically overlapped at the entrance of the main dam of Chungju Dam, while the survey values of approximately 80m horizontally and 10m vertically overlapped in the vicinity of Cheongpung Bridge. It was confirmed.

3-1. Check the performance error with LiDAR survey and MBES survey

In order to evaluate the accuracy of LiDAR and MBES survey data acquired at the main dam entrance of Chungju Dam and near Cheongpung Bridge, the field survey was conducted with a total station, and the performance error between LiDAR survey and MBES survey values based on the local survey values was checked. The results are shown in Tables 6 to 9.

Table 6 shows the local survey values and LiDAR survey performance errors at the main dam entrance of Chungju Dam.

TABLE 6

Store name Local survey reference point LiDAR Survey Performance X Y Z H (L) Dz (Z-H) GCP1 117191.1487 379701.7051 127.412 - - GCP2 117193.0249 379699.4791 127.926 127.57 0.356 GCP3 117194.9598 379697.4874 128.223 128.05 0.173 GCP4 117196.8946 379695.0856 128.523 128.203 0.320 GCP5 117199.1226 379693.0353 128.614 128.259 0.355 GCP6 117201.5851 379691.0436 128.669 128.239 0.430 GCP7 117203.6372 379688.8176 128.796 128.348 0.448 GCP8 117205.6307 379686.7673 128.718 128.245 0.473 GCP9 117208.0346 379684.4241 128.544 128.17 0.374 GCP10 117210.204 379681.9638 128.569 128.145 0.424 GCP11 117211.8457 379679.562 127.504 - - GCP12 117214.1323 379677.0431 128.552 128.033 0.519 GCP13 117216.2431 379675.2271 128.691 - - RMSE RMS 0.398

Table 7 shows the local survey values and the MBES survey performance errors at the main dam entrance of Chungju Dam.

TABLE 7

Store name Local survey reference point MBES Survey Performance X Y Z H (L) Dz (Z-H) GCP1 117191.1487 379701.7051 127.412 - - GCP2 117193.0249 379699.4791 127.926 127.661 0.265 GCP3 117194.9598 379697.4874 128.223 128.078 0.145 GCP4 117196.8946 379695.0856 128.523 128.3 0.223 GCP5 117199.1226 379693.0353 128.614 128.475 0.139 GCP6 117201.5851 379691.0436 128.669 128.472 0.197 GCP7 117203.6372 379688.8176 128.796 128.509 0.287 GCP8 117205.6307 379686.7673 128.718 128.586 0.132 GCP9 117208.0346 379684.4241 128.544 128.602 -0.058 GCP10 117210.204 379681.9638 128.569 128.628 -0.059 GCP11 117211.8457 379679.562 127.504 - - GCP12 117214.1323 379677.0431 128.552 128.617 -0.065 GCP13 117216.2431 379675.2271 128.691 128.454 0.237 RMSE RMS 0.182

From Table 6 and Table 7, it can be seen that the root mean square (RMS) of the LiDAR survey value at the entrance of the main dam of Chungju Dam was worse than the RMS of the MBES survey value. As confirmed during the field inspection, there was a pool of 10 to 20 cm or more in the measurement area, and it was determined that the LiDAR pulse was reflected on the pool to form an irregular TIN.

15 is a view showing the LiDAR TIN performance and MBES TIN performance of the main dam entrance to Chungju Dam.

Table 8 shows the local survey values and LiDAR survey performance errors near Cheongpung Bridge.

TABLE 8

Store name Local survey reference point LiDAR Survey Performance X Y Z H (L) Dz (Z-H) GCP1 110594.701 390023.821 127.976 128.264 -0.288 GCP2 110606.029 390012.097 129.146 129.262 -0.116 GCP3 110603.600 390014.441 129.102 129.019 0.083 GCP4 110600.211 390019.663 128.392 - - GCP5 110597.997 390021.121 128.785 128.731 0.054 GCP6 110608.079 390009.659 129.304 129.308 -0.004 GCP7 110610.838 390066.694 129.468 - - GCP8 110613.307 390003.569 129.405 129.422 -0.017 GCP9 110616.696 390000.349 129.862 129.901 -0.039 GCP10 110619.123 389997.825 130.047 130.105 -0.058 GCP11 110621.132 389995.884 130.269 130.325 -0.056 GCP12 110621.937 389994.313 130.049 130.293 -0.024 GCP13 110622.386 389991.246 129.031 129.153 -0.122 GCP14 110623.787 389989.151 128.836 128.936 -0.100 GCP15 110625.494 389985.964 128.354 128.396 -0.042 GCP16 110627.293 389981.352 127.304 127.54 -0.236 RMSE RMS 0.119

Table 9 shows the local survey values and MBES survey performance errors near Cheongpung Bridge.

TABLE 9

Store name Local survey reference point MBES Survey Performance X Y Z H (L) Dz (Z-H) GCP1 110594.701 390023.821 127.976 128.407 -0.431 GCP2 110606.029 390012.097 129.146 128.981 0.165 GCP3 110603.600 390014.441 129.102 128.931 0.171 GCP4 110600.211 390019.663 128.392 - - GCP5 110597.997 390021.121 128.785 128.771 0.014 GCP6 110608.079 390009.659 129.304 129.203 0.101 GCP7 110610.838 390066.694 129.468 - - GCP8 110613.307 390003.569 129.405 129.46 -0.055 GCP9 110616.696 390000.349 129.862 129.972 -0.110 GCP10 110619.123 389997.825 130.047 130.15 -0.103 GCP11 110621.132 389995.884 130.269 130.256 0.013 GCP12 110621.937 389994.313 130.049 130.141 -0.092 GCP13 110622.386 389991.246 129.031 129.109 -0.078 GCP14 110623.787 389989.151 128.836 129.008 -0.172 GCP15 110625.494 389985.964 128.354 128.574 -0.220 GCP16 110627.293 389981.352 127.304 127.492 -0.188 RMSE RMS 0.167

From Tables 8 and 9, it can be seen that the root mean square (RMS) of the LiDAR measurement values near the Cheongpung Bridge is almost similar to the RMS of the MBES measurement values. As it was confirmed during the field inspection, the measurement area is a rocky terrain where grass does not grow, so the two measurements are almost identical regardless of the data acquisition time.

FIG. 16 is a view showing LiDAR TIN performance and MBES TIN performance near Cheongpung Bridge.

3-2. Surface and cross-sectional surface analysis of TIN interpolation performance of LiDAR and MBES survey values

The peaks and troughs of each survey value are analyzed by longitudinal and cross-sectional surface analysis of the irregular triangular network (TIN) interpolation results of the LiDAR survey values and the triangular interpolation (TIN) interpolation results of the MBES survey values. The identity of the was confirmed.

As a result, as shown in FIG. 17, the peak and trough points of the irregular triangle network (TIN) interpolation performance of LiDAR survey value and the TIN interpolation performance data of MBES measurement value at the entrance of the main dam of Chungju Dam were analyzed in the cross section / cross section surface. Through the same can be confirmed that.

Example 4 Digital Elevation Model (DEM) Integration of LiDAR and MBES

As confirmed in Example 3, the numerical elevation model (DEM) data of the LiDAR survey value is interpolated based on the numerical elevation model (DEM) data of the MBES survey value that is more consistent with the local survey value, and the numerical value of the MBES survey value is interpolated. The digital elevation model (DEM) was constructed at the entrance of the main dam in Chungju Dam, which is the area where the land and water depths coexist by integrating the elevation model (DEM) data with the interpolated LiDAR survey values.

So far, the embodiments of the present disclosure have described a method for constructing a digital elevation model of an area where a land part and a depth part coexist by verifying a TIN interpolation performance of a LiDAR measurement value and an MBES measurement value according to the present invention. In the present specification and drawings, preferred embodiments of the present invention have been disclosed, and although specific terms have been used, these are merely used in a general sense to easily explain the technical contents of the present invention and to help the understanding of the present invention. It is not intended to limit the scope. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

1 is a photograph of a region (a Chungju multi-purpose dam reservoir area) where the land and water depths coexist for measuring the digital elevation model according to an embodiment of the present invention.

2 is a photograph showing the X, Y, Z axis and GPS antenna and LiDAR separation distance measurement of the system of the present invention.

3 is a photograph showing a monitor screen for obtaining a separation distance through a measured value according to an embodiment of the present invention.

4 is a map showing a region (a member of Budang-dong, Cheonan-si, Chungcheongnam-do) selected for aviation laser survey calibration according to an embodiment of the present invention.

5 is an explanatory diagram for calculating the normal elevation using the ellipsoid height and the elevation deviation.

6 is a layout diagram of a normal elevation transformation survey according to an embodiment of the present invention.

7 is a photograph showing a data processing process of LiDAR survey data according to an embodiment of the present invention (a: GPS / INS raw data conversion to GrafNav format, b: RAW data ALS PP (ALS Post Processol) data) Conversion, c: ALS PP to LAS data).

FIG. 8 is a diagram illustrating an example of DEM construction through reflected wave extraction and ground classification (a: Terrascan LAS data lead, b: pre-classified LAS data, c: first reflected wave, d: second reflected wave, and e: Ground classification).

9 is a diagram showing the results of the digital elevation model (DEM) fabrication of LiDAR measurement values.

10 is an explanatory diagram showing the position and correction value for each MBES equipment according to an embodiment of the present invention.

11 is an explanatory diagram showing a calibration of an MBES system according to an embodiment of the present invention.

12 is a photograph showing a data processing process of MBES survey data according to an embodiment of the present invention (a: Navi-PAC program, b: Navi-Scan program, c: Navi-Scan program).

13 is a diagram illustrating a DEM generation process using NaviScan S / W according to an embodiment of the present invention.

14 illustrates DEM fabrication results of MBES measurement values according to an embodiment of the present invention.

15 is a view showing the LiDAR TIN performance and MBES TIN performance of the main dam entrance to Chungju Dam.

FIG. 16 is a view showing LiDAR TIN performance and MBES TIN performance near Cheongpung Bridge.

17 is a diagram confirming whether the highest and lowest points are identical through longitudinal / cross-sectional surface analysis of irregular triangular network (TIN) interpolation performance data of LiDAR and MBES survey values at the entrance of the main dam of Chungju Dam.

18 is a view showing a DEM manufacturing performance integrating LiDAR DEM construction performance and MBES DEM construction performance according to an embodiment of the present invention.

Claims (6)

To build a digital elevation model for a region where the land and depth coexist by verifying the TIN interpolation of LiDAR and MBES survey values, including: (a) surveying coordinates and altitude using an aircraft equipped with a GPS / INS and an air laser survey instrument (LiDAR) to a land part in an area where the land part and the depth part coexist; (b) surveying coordinates and depths using a vessel to which a DGPS and a multi-beam echo sounder (MBES) are attached to a depth portion of an area where the land portion and the depth portion coexist; (c) converting the LiDAR and MBES measurement values measured in the steps (a) and (b) to the height level; (d) constructing respective digital elevation model (DEM) data based on the LiDAR and MBES survey values converted from the normal elevation in step (c); (e) The LiDAR survey and the MBES survey are both co-located with a plurality of land and water depths in which the LiDAR survey and the MBES survey have been conducted. Selecting an area of 5 m or more in length and performing local inspection; (f) After performing the interpolation of the irregular triangle network (TIN) of the LiDAR survey values and the interpolation of the random triangle network (TIN) of the MBES survey values, based on the local survey values measured in the field survey in step (e). Respectively checking the accuracy; (g) Determine the equality of the highest and lowest points of each survey value by analyzing the longitudinal and cross-sectional surfaces of the TIN interpolation performance of the LiDAR survey values and the TIN interpolation performance of the MBES survey values. Making; (h) if the survey value having a random interpolation (TIN) interpolation result that is more consistent with the local survey value identified in step (f) is a LiDAR survey value, the LiDAR numerical elevation model constructed in step (d) ( MBES digital elevation model (DEM) data are interpolated based on the DEM data, and a survey value having an irregular triangular network (TIN) interpolation result that is more consistent with the local survey value identified in step (f) is an MBES survey value. In this case, interpolating LiDAR numerical elevation model (DEM) data based on MBES numerical elevation model (DEM) data constructed in step (d); And (i) superimposing the digital elevation model (DEM) data of the LiDAR measurement values constructed in step (d) with the digital elevation model (DEM) data of the MBES measurement values interpolated in step (h) based on the On the basis of this, the digital elevation model (DEM) data of the MBES survey values constructed in step d) and the digital elevation model (DEM) data of the LiDAR measurement values interpolated in step (h) are superimposed so that the land part and the depth part coexist together. Build a regional digital elevation model (DEM). The method of claim 1, wherein the area where the land part and the depth part coexist together is an area where the quantity of water changes over time. The method of claim 1, wherein the land and water depths coexist together is selected from the group consisting of rivers, rivers, reservoirs, dams and the sea. The method of claim 1, wherein the airborne laser survey (LiDAR) survey of the step (a) is measured when the water level of the depth portion of the area where the land portion and the depth portion coexist together is below the average level. 2. The method of claim 1, wherein the multi-beam echo sounder (MBES) survey of the step (b) is measured when the water level of the area where the land part and the depth part coexist together is above the average level. delete

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