Surveying system and positioning device

Abstract

This surveying system comprises: a ground control point (12) disposed on land to be surveyed; and a positioning device (14) which is provided with a GNSS receiver and a memory and which is placed on the upper surface of the ground control point (12), wherein the positioning device (14) performs GCP positioning by receiving satellite radio waves via the GNSS receiver while placed on the upper surface of the ground control point (12), and stores GCP positioning data acquired as a result of the positioning in the memory.

Description

Surveying systems and positioning devices

[0001] The present invention relates to a surveying system and a positioning device.

[0002] Photogrammetry using cameras mounted on aircraft, drones, and other flying objects is a well-known method for surveying construction sites. In photogrammetry, the aircraft takes aerial photographs of the site to be surveyed. After the aerial photographs are completed, the captured images are analyzed to generate survey data. Before the aircraft takes the aerial photographs, information on ground control points (GCPs), which are reference points for correcting the position coordinates of the captured images, is used to accurately calculate the position of the captured images. A GCP is a reference point whose position coordinates are known and which has a distinctive shape or pattern that is visible on the image. An airborne marker with a specific shape or pattern is installed on the ground as a GCP. The position coordinates of the airborne marker installed on the ground are measured using a total station, a Global Navigation Satellite System (GNSS) surveying instrument, or the like. After the above preparations are completed, the aircraft takes aerial photographs. After the aerial photographs are completed, point cloud data is created based on the captured images. The created point cloud data can be used to create a highly accurate 3D model by applying GCP to correct image distortion or by stitching together multiple images to correct the entire point cloud data.

[0003] In the above-mentioned aerial photography survey, the preparatory work prior to the aerial photography involves installing numerous aerial markers on the ground and measuring their positions, which requires expensive measurement equipment and skilled personnel, resulting in a time-consuming and labor-intensive process. To address this issue, Patent Document 1 discloses a tracking mat on the ground that displays aerial markers on its top surface and includes a GPS (Global Positioning System) tracking unit, a microcontroller, a memory unit, a wireless network connection unit, and a power source. The installation position is acquired from the GPS tracking unit, and the acquired position data is stored in the memory unit. This simplifies the process of measuring the positions of installed aerial markers before aerial photography.

[0004] U.S. Pat. No. 1,108,6025

[0005] However, the above technology requires the preparation of multiple tracking mats, each equipped with a GPS tracking unit or the like, as anti-aircraft markers. These tracking mats are more expensive than regular anti-aircraft marker sheets with specific patterns, and procuring multiple such tracking mats requires significant costs. Furthermore, these tracking mats are larger and heavier than regular anti-aircraft markers and cannot be folded, so transporting multiple tracking mats to the site, setting them up on the ground, and retrieving them is laborious.

[0006] The present invention has been made in consideration of the above circumstances, and aims to install an anti-aircraft beacon and perform GCP positioning at low cost without requiring labor for carrying, installing, and retrieving.

[0007] In order to achieve the above object, the surveying system of the present invention comprises an aerial marker placed on land to be surveyed, and a positioning device equipped with a GNSS receiving unit and a memory unit and mounted on the upper surface of the aerial marker, wherein the positioning device, while mounted on the upper surface of the aerial marker, receives satellite radio waves using the GNSS receiving unit to perform GCP positioning, and stores the GCP positioning data obtained by positioning in the memory unit.

[0008] According to the present invention, a positioning device equipped with a GNSS receiver is placed on an airborne marker placed on the ground to perform GCP positioning, which makes it possible to install the airborne marker and perform GCP positioning at low cost and without requiring effort for carrying, installing, and retrieving it.

[0009] FIG. 1 is a diagram showing an overview of a surveying system according to an embodiment of the present invention. FIG. 2 is a flowchart showing the process of surveying by the surveying system according to an embodiment of the present invention. FIG. 3 is a diagram showing the configuration of a positioning device according to an embodiment of the present invention. FIG. 4 is a diagram showing an overview of the process of GCP positioning according to an embodiment of the present invention. FIG. 5 is a flowchart showing GCP positioning processing according to an embodiment of the present invention. FIG. 6 is a diagram showing an overview of image uploading according to an embodiment of the present invention. FIG. 7 is a flowchart showing image upload processing according to an embodiment of the present invention. FIG. 8 is a flowchart showing image upload data extraction processing according to an embodiment of the present invention.

[0010] A surveying system according to an embodiment of the present invention will be described in detail below with reference to the drawings.

[0011] The surveying system 1 uses an unmanned aerial vehicle (UAV) 10, such as a drone equipped with a camera, to take aerial photographs of land 11 to be surveyed, and generates survey data for the land 11 to be surveyed based on the multiple captured images. As shown in Figure 1, the surveying system 1 includes a plurality of anti-aircraft markers 12 placed on the land 11 to be surveyed, the aircraft 10, and an information processing device 13 that generates survey data for the land 11 to be surveyed based on the multiple captured images taken by the aircraft 10. In addition, a positioning device 14 is installed as a fixed station that generates correction information for the position of the aircraft 10.

[0012] The anti-aircraft marker 12 is an inexpensive, lightweight sheet made of rubber-based resin, vinyl-based resin, metal, wood, or the like, bearing a distinctive identification pattern that is visible in images captured by the aircraft 10. Therefore, the sheet is easy to carry, and does not require much effort to set up and retrieve.

[0013] The aircraft 10 is a UAV such as a drone, and includes a camera for capturing images of the land 11 to be surveyed, a GNSS receiver for receiving radio waves from a satellite 15, and other components. The aircraft 10 also includes a card slot for connecting a removable storage medium, such as a Secure Digital (SD) memory card. The GNSS receiver includes a GNSS antenna and acquires position information such as latitude and longitude, and date and time information based on radio waves from the satellite 15. While only one satellite 15 is shown in FIG. 1 , multiple satellites actually exist, and the GNSS receiver receives radio waves from these multiple satellites. Image data captured by the camera and the position information and date and time information of the aircraft 10 at the time of capturing the image, acquired by the GNSS receiver, are associated with each other and stored in a removable storage medium connected to the aircraft 10.

[0014] The positioning device 14 is a mobile device equipped with a GNSS receiver and a storage unit for storing position information received from satellites 15. The positioning device 14 can be used as a mobile station, and the position of the positioning device 14 is corrected based on correction information generated by a fixed station. The positioning device 14 can also be used as a fixed station, and by fixing to a known position, generates correction information for correcting position information acquired by the aircraft 10. In FIG. 1 , the positioning device 14 is installed as a fixed station at a location whose position is known and near the land to be measured. Here, the positioning device 14 is installed on a pole 16 so that it can easily receive radio waves from satellites 15. The positioning device 14 will be described later.

[0015] The information processing device 13 is a computer that analyzes and processes image data captured by aerial photography, etc. The information processing device 13 is installed in an office or the like away from the site of the survey object.

[0016] Next, the process of surveying using the surveying system 1 described above will be described with reference to the flowchart of FIG. 2 . First, as a preparatory step prior to aerial photography surveying, anti-aircraft markers 12 are installed on the land 11 to be surveyed (step S101). Multiple anti-aircraft markers 12 are installed, for example, at the four corners and the center of the land 11 to be surveyed, as well as at equal intervals. Once installation of the anti-aircraft markers 12 is complete, GCP positioning is performed for each of the multiple anti-aircraft markers 12 (step S102). The surveying of the anti-aircraft markers 12 will be described later. Once the surveying of all the anti-aircraft markers 12 is complete, the aircraft 10 is driven to begin flight and aerial photography is taken from above the land 11 to be surveyed (step S103). The aircraft 10 is controlled by operating a remote control unit (promo) or according to a flight program preset in the aircraft 10. The aircraft 10 captures images using an onboard camera to acquire image data, and receives radio waves from satellites 15 to acquire information about its own location and information about the date and time, which are then stored in a built-in removable storage medium. When the aerial photography is complete, the image data, location information, and date and time information stored in the removable storage medium are sent to the information processing device 13, which performs analysis processing based on this data and creates a three-dimensional model (step S104). This generates measurement data.

[0017] As described above, as preparatory work prior to the aerial photography survey, the processes of steps S101 and S102 are carried out, that is, the anti-aircraft beacon 12 is installed and the installed anti-aircraft beacon 12 is surveyed. Next, the details of this preparatory work will be described.

[0018] As a preparatory step, the user first places a plurality of anti-aircraft markers 12 within the land 11 to be surveyed. As described above, the anti-aircraft markers 12 are commonly used sheets that are easy to carry, inexpensive, lightweight, and do not have any special structure, such as rubber. Once the installation of the anti-aircraft markers 12 is complete, the user then determines the positions of the installed anti-aircraft markers 12, i.e., the GCPs.

[0019] The positioning of each GCP is performed by placing a positioning device 14 with a built-in GNSS receiver on the top surface of the anti-aircraft sign and then receiving radio waves from satellites 15 to obtain information about the position, and the user obtains information about the positions of all the anti-aircraft signs 12 by moving the positioning device 14 sequentially around each anti-aircraft sign 12. Here, the positioning device 14 is used as a mobile station.

[0020] 3 shows the configuration of the positioning device 14. The positioning device 14 includes a GNSS receiving unit 141, a control unit 142, a storage unit 143, a wireless communication module 144, an operation unit 145, a display unit 146, and an interface unit 147.

[0021] The GNSS receiver 141 includes a GNSS antenna and acquires position information such as latitude and longitude, and date and time information based on radio waves from the satellites 15. The control unit 142 includes a computer having a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and the like. The control unit 142 performs various controls by reading various operating programs stored in the ROM and executing them on the RAM. The memory unit 143 stores the position information and date and time information of each anti-aircraft beacon 12 acquired by the GNSS receiver 141. When the positioning device 14 is used as a fixed station, the memory unit 143 also stores log data of signals received from the satellites 15 for generating correction information. The wireless communication module 144 includes an interface for communicating with mobile terminal devices such as tablets and smartphones via a wireless local area network (LAN) such as Wi-Fi (registered trademark), Bluetooth (registered trademark), or the like, and wirelessly communicates with the mobile terminal devices via an antenna (not shown). The operation unit 145 is a device for inputting various instructions to the control unit 142, and includes operation buttons for starting and stopping measurement, a keyboard, a touch panel, etc. The display unit 146 includes a display device such as an LCD (Liquid Crystal Display) panel or an organic EL (Electro-Luminescence) panel that displays screens showing the execution results of various processes, operation screens, etc. The interface unit 146 is a USB (Universal Serial Bus) interface, and includes a USB receptacle for connecting a USB memory or the like, and stores the location information and date and time information stored in the storage unit in the USB memory.

[0022] Next, measurement of the installation position of each anti-aircraft beacon 12, i.e., the GCP positioning process of step S102 in Fig. 2, will be described with reference to Fig. 4 and Fig. 5. Fig. 4 shows an overview of the process of placing the positioning device 14 on the upper surface of the anti-aircraft beacon 12 and performing GCP positioning, and Fig. 5 is a flowchart showing the GCP positioning process.

[0023] First, the portable terminal device 21, such as a tablet or smartphone, requests a wireless communication connection from the positioning device 14 in accordance with setting information, such as a Wi-Fi connection ID and password, stored in ROM or RAM, and establishes a wireless communication connection between the portable terminal device 21 and the positioning device 14 (step S201). Once the wireless communication connection is established, the portable terminal device 21 transmits setting information, such as a positioning method and a mask angle, to the positioning device 14 via a wireless communication module. The portable terminal device 21 also sets the number of installed anti-aircraft beacons 12, i.e., the number of GCPs to be measured. Upon receiving the setting information transmitted from the portable terminal device 21, the positioning device 14 performs various settings in accordance with the setting information (step S202).

[0024] Here, post-processing kinematic positioning (PPK) is used as the positioning method. In kinematic positioning, both a GNSS receiver at a fixed station installed at a known point and a GNSS receiver at a mobile station (an unknown point) observe the phase of the carrier wave from the satellite. The fixed station generates correction information from the observed carrier wave phase information and the position information of the known point where the fixed station is installed. The phase information of the carrier wave observed at the fixed station and the phase information of the carrier wave observed at the mobile station are analyzed to determine the positional relationship between them from the phase difference, and the position of the unknown point, the mobile station, is determined from the position information of the known point where the fixed station is installed. In post-processing kinematic positioning (PPK), observation data observed at the fixed station and the mobile station are temporarily stored and later analyzed to determine the position of the mobile station. Note that for fixed stations, observation data from electronic reference points or virtual reference points can be downloaded from a distribution site and used later instead of observation data from the GNSS receiver.

[0025] Once the settings are complete, the user moves the positioning device 14 to the location of the anti-aircraft beacon 12. In Fig. 4, the user moves the positioning device 14 in the direction of the arrow and places it in the center of the top surface of the anti-aircraft beacon 12. After placing the positioning device 14, the user presses the measurement button from among the buttons on the operation unit 145 provided on the positioning device 14 (step S203).

[0026] By pressing the measurement button, the positioning device 14 performs GCP positioning of the anti-aircraft beacon 12 on which it is placed (step S204). The positioning device 14 receives radio waves from the satellite 15 using the built-in GNSS receiver 141 to acquire observation data. The observation data includes carrier phase information, date and time information at the time of positioning obtained from the signal code, and uncorrected position information. Here, because the positioning device 14 is located higher than the ground, the measured position is higher than the position of the anti-aircraft beacon 12. Therefore, information indicating its own height from the ground is input and stored as pre-setting information in the positioning device. Based on this height information, the position measured by the positioning device 14 is corrected to the position of the anti-aircraft beacon 12.

[0027] When measurement of the position of one anti-aircraft beacon 12 is completed, the positioning device 14 stores the acquired observation data in the memory unit 143. The measured anti-aircraft beacon 12 and the observation data of that anti-aircraft beacon 12 are stored in association with each other. For example, a number is assigned to each anti-aircraft beacon 12, and the number is associated with the observation data. When measurement of the position of one anti-aircraft beacon 12 is completed, it is determined whether measurement of the positions of all installed anti-aircraft beacons 12 has been completed (step S205). As described above, the number of installed anti-aircraft beacons 12 is preset by the mobile terminal device 21. The positioning device 14 compares the number of set anti-aircraft beacons 12 with the number of anti-aircraft beacons 12 for which measurement has actually been completed. If the comparison shows that the number of anti-aircraft markers 12 that have actually been measured does not reach the set number of anti-aircraft markers 12, i.e., if the measurement of the positions of all anti-aircraft markers 12 has not been completed (step S205: No), the positioning device 14 displays on the display unit 146 a message indicating that the measurement of the positions of all anti-aircraft markers 12 has not been completed, e.g., the number of remaining anti-aircraft markers 12 for which measurement has not been completed. Furthermore, each time the measurement of the position of each anti-aircraft marker 12 is completed, the positioning device 14 displays on the display unit 146 a diagram showing the relative positional relationship between the anti-aircraft markers 12 and the other anti-aircraft markers 12 that have been measured, based on the acquired position information. This display allows the user to recognize anti-aircraft markers 12 for which measurement has not been completed. Furthermore, if an anti-aircraft marker 12 placed in the same position is accidentally measured twice, the positioning device 14 may leave the remaining number displayed unchanged and display a message indicating that the measurements are duplicated. The user moves the positioning device 14 from the position of the anti-aircraft sign 12 for which measurement has been completed toward an anti-aircraft sign 12 that has not yet been measured, and places it at the center of the top surface of that anti-aircraft sign 12 (step S206).

[0028] When the positioning device 14 is placed on the top surface of the next anti-aircraft beacon 12, the positioning process of the above-mentioned steps S203 and S204 is performed, and when the measurement is completed, the user checks whether GCP positioning has been performed for all anti-aircraft beacons 12 (step S205), and repeats the processes of steps S203 to S206 until there are no unmeasured anti-aircraft beacons 12. When the positions of all anti-aircraft beacons 12 have been measured (step S205: Yes), the user ends the GCP positioning process.

[0029] As described above, after installing a plurality of commonly used sheet-like anti-aircraft markers 12 on the ground, the positioning devices 14 are placed on the plurality of anti-aircraft markers 12 in sequence to measure the position of each anti-aircraft marker 12. Therefore, GCP positioning can be performed by placing the positioning devices 14 in sequence without using special anti-aircraft markers 12, thereby enabling inexpensive and easy GCP positioning. Furthermore, since measurements are performed by placing the positioning devices 14 in sequence, only one positioning device 14 is required, thereby reducing the cost required for GCP positioning. GCP positioning may be performed using not only one but also multiple positioning devices 14. In this case, the time required for GCP positioning can be shortened. Furthermore, while the above measurement is performed before aerial photography by the aircraft 10, GCP positioning may also be performed simultaneously while the aerial photography is being performed. Furthermore, in the above measurement, the positioning device 14 is recovered after the measurement is completed and before the aerial photography is performed, but the aerial photography may be performed while the positioning device 14 is still placed on the anti-aircraft marker 12.

[0030] Once the above preparation work is completed, aerial photography is performed using the aircraft 10. Here, the GNSS-based positioning method used is post-processed kinematic positioning (PPK). In FIG. 1 , the positioning device 14 used for the GCP positioning process in the preparation work is installed as a fixed station at a known point, and the aircraft 10, which serves as a mobile station and serves as an observation point, moves while determining the relative position of the observation point with respect to the known point. When using the positioning device 14 as a fixed station, input is made via the operation unit 145 to set it to fixed station mode for use as a fixed station. The positioning device 14 is installed near the land 11 to be measured and receives radio waves from a satellite 15 to acquire observation data. The positioning device 14 is installed on a pole 16 to facilitate reception of radio waves from the satellite, but it may also be installed directly on the ground. When installed on a pole 16, information on the height of the pole 16 is stored in the memory unit 143 within the positioning device 14.

[0031] The aircraft 10 begins flight by operation via a remote control or automatic control according to preset flight path information. Upon arriving at the surveying location, the aircraft 10 acquires mobile station observation data, which is observation data generated by receiving radio waves from satellites 15 with a GNSS receiver built into the aircraft 10, and generates image data by photographing the land to be surveyed with a camera mounted on the aircraft 10. Here, the mobile station observation data includes carrier wave phase information, image date and time information obtained from the signal code, and uncorrected position information, as described above. The aircraft 10 acquires image data and mobile station observation data at predetermined intervals while flying above the land to be surveyed. The acquired data is stored in a memory unit within the aircraft 10. During aerial photography, the positioning device 14 installed at a fixed point acquires fixed station observation data (hereinafter referred to as PPK log data), which is observation data generated by receiving satellite radio waves with the built-in GNSS receiver 141. The acquired fixed station observation data is stored in a memory unit 143 within the positioning device 14. When the aerial photography by the aircraft 10 is completed, the aircraft 10 reads out the image data and mobile station observation data stored in the memory unit and writes them to a removable storage medium connected to the aircraft 10.

[0032] As described above, once the aerial photography is completed, the user removes the removable storage medium storing the image data, etc., from the aircraft 10 and transmits the image data, etc. stored on the removable storage medium to the information processing device 13. The information processing device 13 then performs an analysis process to create a three-dimensional model based on the transmitted data. Furthermore, for the analysis, in addition to the aerial image data and the mobile station observation data of the aircraft 10, PPK log data, which is fixed station observation data, and GCP positioning data installed within the land to be surveyed are required. Image data, etc., is typically transmitted to the information processing device 13 from a personal computer installed in an office or the like that is communicatively connected to the information processing device 13. Image data, etc., is transmitted to the personal computer by connecting a removable storage medium storing the image data, etc., to the personal computer. However, it is inconvenient to travel to a location far from the surveying site to transmit data. In this embodiment, image data, etc., is transmitted to the information processing device 13 from a portable terminal device 21, such as a tablet or smartphone, that can be carried to the surveying site without going through the personal computer. This allows the user to transmit image data and the like to the information processing device 13 without having to travel to a location far from the surveying site, thereby increasing convenience.

[0033] Next, transmission of acquired image data and the like to the information processing device 13 will be described with reference to Fig. 6 and Fig. 7. Fig. 6 shows an overview of uploading image data and the like to the information processing device 13.

[0034] As shown in FIG. 6 , image data and the like are transmitted to the information processing device 13 via a portable terminal device 21, such as a tablet or smartphone, that has been configured for the positioning device 14. The portable terminal device 21 is equipped with a wireless communication module, such as Wi-Fi, and communicates wirelessly via an antenna (not shown). The portable terminal device 21 connects to the positioning device 14 via the wireless communication module and reads PPK log data and the like from the positioning device 14. The portable terminal device 21 also has a slot for connecting a removable storage medium, and connects the removable storage medium removed from the aircraft 10 to read stored image data and the like. Furthermore, the portable terminal device 21 establishes an external wireless communication connection via the wireless communication module and transmits the PPK log data and the like read from the positioning device 14 and the image data and the like read from the removable storage medium to the information processing device 13 via the network 22.

[0035] Next, a procedure for transmitting acquired image data, etc. to the information processing device 13 will be described. The mobile terminal device 21 executes connection processing with the information processing device 13 using an installed application program, and executes processing for transmitting image data, etc. acquired from the aircraft 10 and PPK log data, etc. acquired from the positioning device 14 to the information processing device 13. Figure 7 is a flowchart showing the processing for uploading image data, etc. to the information processing device 13.

[0036] 7 , first, the mobile terminal device 21 requests a wireless communication connection from the positioning device 14, and establishes a wireless communication connection such as Wi-Fi between the terminal device and the positioning device 14 (step S301). Once the wireless communication connection is established, the mobile terminal device 21 requests PPK log data from the positioning device 14 via the wireless communication module, and the positioning device 14 reads the PPK log data from the storage unit 143 and transmits it to the mobile terminal device 21 (step S302). The mobile terminal device 21 also requests GCP positioning data from the positioning device 14, and the positioning device reads the GCP positioning data from the storage unit 143 and transmits it to the mobile terminal device 21. As a result, the mobile terminal device 21 acquires the PPK log data and GCP positioning data from the positioning device 14.

[0037] After reading the necessary data from the positioning device 14, the mobile terminal device 21 disconnects the wireless communication connection with the positioning device 14 and then wirelessly connects to a hotspot such as a Wi-Fi spot (step S303). The hotspot is connected to an external network 22 such as the Internet, and is connected to the information processing device 13 via the network 22. Therefore, the mobile terminal device 21 connects to the hotspot via the wireless communication module, and is able to communicate with the information processing device 13 via the hotspot and the network 22.

[0038] Next, the user removes the removable storage medium from the aircraft 10 and connects the removable storage medium to the portable terminal device 21 by inserting the removable storage medium into a slot provided in the portable terminal device 21 (step S304).

[0039] Next, the user operates an upload button displayed on a display screen such as a liquid crystal display of the portable terminal device 21 (step S305). By operating the upload button, the portable terminal device 21 reads out the image data and mobile station observation data stored in the removable storage medium, and also reads out the PPK log data and GCP positioning data stored in the positioning device 14. The portable terminal device 21 uploads the data by transmitting the data read out from the removable storage medium and the positioning device 14 to the information processing device 13 (step S306).

[0040] As described above, the portable terminal device 21 can be carried around, allowing the user to collect image data and transmit it to the information processing device 13 directly from the surveying site, thereby improving convenience.

[0041] The information processing device 13 performs analysis using SfM (Structure from Motion) analysis software based on the received image data to generate a 3D model of the land 11 to be surveyed. Prior to generating the 3D model, the information processing device 13 performs post-processing analysis to correct errors in the mobile station's position based on PPK log data received by the fixed-station positioning device 14 from satellites 15 during aerial photography and mobile station observation data received by the mobile-station aircraft 10 from satellites 15. The information processing device 13 also performs post-processing analysis to correct errors in the position of the airborne beacon 12 measured by the mobile-station positioning device 14, i.e., the GCP position, based on GCP positioning data for the airborne beacon 12 received by the positioning device 14 from satellites 15 during GCP positioning, and observation data for electronic reference points or virtual reference points downloaded from a distribution site serving as a fixed station. For fixed stations, another positioning device 14 may be installed at a known point and observation data received by the other positioning device 14 from satellites 15 during GCP positioning may be used.

[0042] Therefore, in order to generate a three-dimensional model of the land to be surveyed, in addition to the image data and mobile station observation data stored on a removable storage medium, PPK log data of the fixed station at the time of imaging and GCP positioning data installed within the land 11 to be surveyed are required.

[0043] However, while the aerial image data, etc., are stored on a removable storage medium within the aircraft, the PPK log data and GCP positioning data are stored in the memory unit 143 within the positioning device 14, which is a separate medium from the removable storage medium within the aircraft. In such cases, the aerial image data, etc., and the PPK log data and GCP positioning data may be data for a different piece of land than the same measurement target land 11. Furthermore, even if the data is for the same piece of land, it may be data from different dates and times. In this case, if data for a different piece of land and a different date and time is mistakenly collected and analyzed, a 3D model that differs from the actual one will be generated. Therefore, it is necessary to ensure that the image data, etc., uploaded from the mobile terminal device 21 to the information processing device 13 is data for the same or corresponding location and image date and time.

[0044] 7, the upload button is operated and data is uploaded in step S306, and at this time, data read from the removable storage medium and data read from the positioning device 14 that corresponds to the data read from the removable storage medium are uploaded. Fig. 8 shows the process of the mobile terminal device 21 extracting and uploading data to be uploaded in steps S305 and S306 of Fig. 7.

[0045] 8, with the upload button displayed on the display screen, the mobile terminal device 21 determines whether the upload button has been operated (step S401). If the user operates the upload button and it is determined that the upload button has been operated (step S401: Yes), the mobile terminal device 21 displays a list of data files stored in the removable storage medium on the display screen (step S402). If it is not determined that the upload button has been operated (step S401: No), the processing of step S401 is repeated.

[0046] When the list of data files is displayed on the display screen, the user selects a data file to be uploaded to the information processing device 13 from the displayed list of data files. At this time, the mobile terminal device 21 determines whether a data file to be uploaded has been selected (step S403). If it is determined that a data file has been selected (step S403: Yes), the mobile terminal device 21 extracts location information and date and time information from the selected data file (step S404). If it is determined that a data file has not been selected (step S403: No), the processing of step S403 is repeated.

[0047] A data file is created for each project (site), and includes aerial image data and mobile station observation data acquired by the GNSS receiver at the time of image capture. The observation data includes carrier phase information, date and time information calculated from the signal code, and uncorrected location information. The data file also includes the project name in its file name. Note that the file name may include date and time information or location information instead of or in addition to the project name.

[0048] In step S404, the mobile terminal device 21 extracts location information and date and time information from the date and time information and pre-corrected location information included in the mobile station observation data of the selected data file. Regarding location information, the project name may be extracted from the file name and used as location information. Furthermore, if date and time information or location information is included in the file name, the date and time information and location information may be extracted from this.

[0049] Next, the mobile terminal device 21 extracts corresponding PPK log data and GCP positioning data from the PPK log data and GCP positioning data read out from the positioning device 14 based on the extracted position and date and time information (step S405).

[0050] In step S302, the mobile terminal device 21 reads the PPK log data and GCP positioning data from the positioning device 41 and stores them in a memory unit within the mobile terminal device 21. The PPK log data and GCP positioning data each have a data file for each project. The PPK log data data file includes the project name, location information of the installation location of the fixed station (known point), and fixed station observation data acquired by the GNSS receiver during imaging. The fixed station observation data includes carrier phase information and date and time information calculated from the signal code. The data file includes the project name in its file name. Note that the file name may include date and time information or location information instead of or in addition to the project name. The GCP positioning data data file includes the project name and observation data acquired by the GNSS receiver during GCP positioning. The observation data includes carrier phase information, date and time information calculated from the signal code, and uncorrected position information. Like the PPK log data, the data file includes the project name in its file name. Instead of or in addition to the project name, the file name may include date and time information or location information.

[0051] The mobile terminal device 21 compares the location information and date and time information extracted from the removable storage medium with the location information and date and time information contained in the PPK log data and GCP positioning data stored in the memory unit, and identifies the PPK log data and GCP positioning data necessary for analyzing the image data.

[0052] For example, it is determined whether the location represented by the location information included in the PPK log data is within a predetermined range from the imaging location represented by the location information extracted from the removable storage medium. Because the PPK log data is data acquired when the positioning device 14 is used as a fixed station, the location represented by the location information included in the PPK log data is somewhat distant from the imaging location of the image data. Therefore, the predetermined range is set taking into account the distance from the fixed station. If the location represented by the location information included in the PPK log data is determined to be within a predetermined range from the imaging location of the image data, it is identified as the same measurement target site. Furthermore, if a project name is stored in the data file or the file name includes the project name, the project name can be read from these to similarly identify the same measurement target site.

[0053] Furthermore, for the GCP positioning data, it is determined whether the position indicated in the position information is within a predetermined range from the imaging position of the image data. The predetermined range is set taking into consideration the size of the site of the measurement target, measurement error, etc. If it is determined that the position indicated in the position information included in the GCP positioning data is within a predetermined range from the imaging position of the image data, it is identified as the site of the same measurement target. Furthermore, if a project name is stored in the data file of the GCP positioning data or if the project name is included in the file name, it is possible to similarly identify the site of the same measurement target by reading out the project name.

[0054] Furthermore, it is determined whether the date and time indicated in the date and time information included in the PPK log data and the GCP positioning data is within a predetermined range from the image capture date and time of the image data. Since the date and time at which the PPK log data is acquired is approximately the same as the image capture date and time, the predetermined range is set narrower. In contrast, for the GCP positioning data, the data may be measured simultaneously with the image capture date and time, but may also be measured before or after the image capture date and time, so the predetermined range is set wider than for the PPK log data.

[0055] If it is determined that the location indicated in the location information included in the PPK log data is within a predetermined range from the imaging location of the image data, and if it is determined that the date and time indicated in the date and time information included in the PPK log data is within a predetermined range from the imaging date and time of the image data, the determined PPK log data is identified as the PPK log data to be uploaded together with the data file stored on the removable storage medium for which upload selection has been made.

[0056] Furthermore, if it is determined that the position indicated in the position information included in the GCP positioning data is within a predetermined range from the imaging position of the image data, and if it is determined that the date and time indicated in the date and time information included in the GCP positioning data is within a predetermined range from the imaging date and time of the image data, the determined PPK log data is identified as the GCP positioning data to be uploaded together with the data file stored on the removable storage medium for which upload selection has been made.

[0057] When the PPK log data and GCP positioning data to be uploaded are identified, the identified PPK log data and GCP positioning data are extracted, and the extracted PPK log data and GCP positioning data are sent to the information processing device together with the data file stored in the selected removable storage medium (step S406).

[0058] As a result, when generating a 3D model of the land to be surveyed, image data, etc., along with the corresponding PPK log data and GCP positioning data, are sent together to the information processing device, so that the information processing device does not generate an incorrect 3D model, and instead generates a correct 3D model.

[0059] Prior to generating the three-dimensional model, the information processing device 13 determines the position of the aircraft 10 by post-processing analysis based on the PPK log data received from the mobile terminal device 21 and the mobile station observation data of the aircraft 10. In addition, based on the GCP positioning data received from the mobile terminal device 21 and the observation data of electronic reference points or virtual reference points downloaded from a distribution site serving as a fixed station, the information processing device 13 determines the position of the anti-aircraft beacon 12, i.e., the position of the GCP, by post-processing analysis.

[0060] The information processing device 13 executes an analysis process using SfM analysis software based on the received image data to generate a 3D model of the land 11 to be surveyed. In the SfM analysis, the imaging position and imaging attitude of the camera are calculated using bundle calculation for the image data, and a 3D model composed of point cloud data is generated. Here, the position information of the aircraft 10 is used in the bundle calculation. By applying a GCP to the generated point cloud data, a correction process is performed to associate the coordinate system of the relative positional relationship with the geographic coordinate system, and a highly accurate 3D model is generated.

[0061] In this way, the information processing device 13 can receive PPK log data and GCP positioning data corresponding to image data taken from the air of the land 11 to be surveyed from the mobile terminal device 21 all at once, so there is no need to search for PPK log data and GCP positioning data corresponding to the image data later, and the risk of performing analysis work using incorrect PPK log data and GCP positioning data is reduced, making it possible to generate a correct three-dimensional model of the land 11 to be measured.

[0062] In the above embodiment, the portable terminal device 21 connects to the positioning device 14 via a wireless communication module and reads PPK log data, etc. from the positioning device 14, but this is not limiting; the portable terminal device 21 may also be connected to the positioning device 14 via a wired cable to read PPK log data, etc. from the positioning device 14. Also, in the above embodiment, the air vehicle 10 is configured to store image data, etc. in a removable storage medium, but if the air vehicle 10 is configured to store image data, etc. in a storage medium other than a removable storage medium and read image data, etc. via wireless communication such as Wi-Fi or via a wired communication connection to a terminal such as a USB, the portable terminal device 21 may connect to the storage medium via wireless communication or wired communication and read the stored image data, etc.

[0063] The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. Furthermore, the above-described embodiments are intended to illustrate the present invention and do not limit the scope of the present invention. In other words, the scope of the present invention is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and within the meaning of the disclosure equivalent thereto are considered to be within the scope of the present invention.

[0064] The present invention can be widely applied to surveying systems that generate three-dimensional models by installing anti-aircraft markers on land to be surveyed and taking aerial photographs.

[0065] 1 Surveying system, 10 Aircraft, 11 Land to be surveyed, 12 Airborne marker, 13 Information processing device, 14 Positioning device, 15 Satellite, 21 Terminal device, 22 Network, 141 GNSS receiving unit, 142 Control unit, 143 Memory unit, 144 Wireless communication module, 145 Operation unit, 146 Display unit, 147 Interface unit.

Claims

1. A surveying system comprising: an aerial marker placed on land to be surveyed; and a positioning device equipped with a GNSS receiving unit and a memory unit and mounted on the top surface of said aerial marker, wherein said positioning device, while mounted on the top surface of said aerial marker, receives satellite radio waves using said GNSS receiving unit to perform GCP positioning, and stores the GCP positioning data obtained by positioning in said memory unit.

2. The surveying system of claim 1, wherein there are a plurality of aerial markers, each placed at a different location on the land to be surveyed, and the positioning device repeats positioning of the GCP and storing the acquired GCP positioning data in the memory unit each time the positioning device is placed on each of the plurality of aerial markers in sequence.

3. The surveying system according to claim 1, wherein the anti-aircraft marker is a sheet having an identification pattern formed on its surface.

4. A surveying system as described in claim 1 or 2, comprising a terminal device and an information processing device that generates a three-dimensional model of the land to be surveyed, wherein the terminal device is communicatively connected to the positioning device, requests the GCP positioning data from the positioning device, receives the GCP positioning data from the positioning device, and then wirelessly connects to the information processing device and transmits the GCP positioning data to the information processing device.

5. The surveying system according to claim 4, wherein the terminal device is connected to an aircraft equipped with a camera and a GNSS receiver, and connects a storage medium storing image data of the land to be surveyed taken by the camera and observation data acquired by the GNSS receiver, reads out the image data and the observation data, extracts the GCP positioning data corresponding to the image data based on date and time information of the image data taken contained in the observation data and date and time information of positioning contained in the GCP positioning data, or location information of the image data taken contained in the observation data and location information of positioning contained in the GCP positioning data, and transmits the image data and the extracted GCP positioning data to the information processing device.

6. A positioning device that is placed sequentially on a plurality of airborne markers placed on land to be surveyed and measures the position of each airborne marker, comprising: an operation unit that instructs the measurement; a GNSS receiving unit that receives radio waves from satellites to perform GCP positioning and acquire GCP positioning data; a display unit that displays the relative positional relationship of each airborne marker based on the position information contained in the acquired GCP positioning data for the airborne markers from which the GCP positioning data has been acquired; and a memory unit that stores the acquired position information.

7. A positioning device as described in claim 6, which is fixed to a known point close to the land to be surveyed, acquires fixed station observation data which is observation data generated by receiving radio waves from a satellite with the GNSS receiving unit as a fixed station when the land to be surveyed is photographed from the air by an aircraft, and stores the acquired fixed station observation data in the memory unit.

8. A surveying system comprising: the positioning device of claim 7; an aircraft equipped with a camera and a GNSS receiver; an information processing device that processes image data of the land to be surveyed taken by the camera and mobile station observation data, which is observation data acquired by the GNSS receiver at the time of taking the image; and a terminal device, wherein the terminal device acquires the image data and the mobile station observation data from the aircraft, connects to the positioning device via communication to receive the GCP positioning data transmitted from the positioning device, and connects to the information processing device via wireless communication to transmit the image data, the GCP positioning data, the fixed station observation data and the mobile station observation data to the information processing device.

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