NL2035443B1

NL2035443B1 - System and method for monitoring a dyke

Info

Publication number: NL2035443B1
Application number: NL2035443A
Authority: NL
Inventors: Duijts Camiel; Duijts Dennis; Wouters Eva
Original assignee: Deltaiot B V
Priority date: 2023-07-20
Filing date: 2023-07-20
Publication date: 2025-01-30
Also published as: WO2025017163A1

Abstract

A system and method for monitoring the shape and size (deformation) of a dyke is disclosed. This method employs the monitoring of settlement plate position by an unmanned aerial vehicle UAV.

Description

Reference: DeltaloT 2s — 30.06.2023

System and method for monitoring a dyke

Field of the invention [1 The present invention relates to a system and method to determine and monitor the profile, size and shape (deformation) of a dyke or similar terrain over a time period.

Background art

[2] Patent document US8138970B2 discloses a multi-antenna global navigation satellite system (GNSS) receiver system and method provide earth-referenced GNSS heading and position solutions. The system and method compensate for partial blocking of the antennas by using a known attitude or orientation of the structure, which can be determined by an orientation device or with GNSS measurements. Multiple receiver units can optionally be provided and can share a common clock signal for processing multiple GNSS signals in unison. The system can optionally be installed on fixed or slow-moving structures, such as dams and marine vessels, and on mobile structures such as terrestrial vehicles and aircraft. This system requires the individual receivers to be connected by a network of cables. Cables can easily damaged in an environment in which construction work is performed.

[3] Measuring heights and positions of portions of a landscape is well known in the field of geological monitoring. Patent document US2020/0326187A1 discloses a monitoring method wherein: a target is prepared using terrain model data including terrain location information; at a first time, an image of the target is picked up by means of an image pickup unit of a surveying device, and first image data is generated; at a second time after the first time, an image of the target is picked by means of the image pickup unit of the surveying device, and second image data is generated; and displacement of the target is detected using a first image based on the first image data, and a second image based on the second image data. The system of

US2020/0326187A1 employs GNSS receivers to determine if the position of a location to be monitored has changed. In this system a unmanned aerial vehicle (UAV) is employed before the monitoring, to photograph a wide-area observation object to be observed using a camera. Then, terrain model data is generated from the obtained aerial photographs, and one or more observation objects are selected from the wide-area observation object using the terrain model data. The monitoring is performed by a survey instrument, such as a total station theodolite (TST).

Survey instruments such as a TST require an unobstructed line of sight to the targets to be monitored. Therefore, such a system can monitor only one side of a dyke.

[4] Autonomous unmanned aerial vehicles can be stored in an individual housing. Such systems are known as “Drone in a Box’, see https://en.wikipedia.org/wiki/Drone_in_a_ Box and are widely commercially available, e.g. .https://dronehub.ai/solutions/.

[5] In the field of monitoring ground constructions, settlement plates are commonly used for holding geological survey equipment. Such a settlement plate, suitable for holding for holding survey equipment on a terrain to be monitored is known from https ://www.geokon.com/content/datasheets/4625 Settlement Plate.pdf. This online document

Reference: DellalaT 03 — 30.06.2023 -2- describes a settlement plate having a base plate made from plywood or steel and a modular extension rod.

[6] The inventors overcame the deficiencies of the prior art by utilizing a set of settlement plates equipped with visual markers and optionally with GNSS receivers.

Summary of the invention

[7] According to the present invention, settlement plates are installed in the region of the dyke to be monitored in a regular pattern. These settlement plates are provided with a unique visual marker on top of the settlement plate’s rod. Settlement plates at strategically important reference. positions, such as the outer corners of the area to be monitored, will additionally be equipped with GNSS receivers. The monitoring of the settlement plate positions will be performed by at least one UAV in regular intervals. The at least UAV records images from the visual markers and stores said imaged together with metadata. A computing unit will then calculate from the image data and the metadata the top-position of each settlement plate and thereby determine the deformation of the underlying dike body and outer shape and size of the terrain of the dyke body.

[8] One advantage of the present invention is that the system can monitor a large area without the need of installing any infrastructure. The size of the area is limited by the capabilities of the UAV in terms of flight time and speed only. The UAV may be programmed with a predetermined flight path, such that communications to a control station is not necessary, which would allow the UAV to reach beyond the radio horizon of the control station.

[9] The UAV returns to its control station, once a monitoring missing in finished. At the control! station the UAV may automatically charged.

[10] Further, the image data and metadata may be offloaded when the drone is parked at the control station. Offloading of the image data and metadata can also happen during the flight, either with a direct communication link to the control station or by means of wireless communication technology such as 3G, 4G and 5G. When using the latter, the UAV can leave the communication radius of its control station, while still be able to offload data in essentially real time.

[11] In a further embodiment, settlement plates are only installed on particular important strategic reference positions in the terrain to be monitored. The monitoring of the terrain will be performed by at least one UAV in regular intervals. The at least UAV records images from the visual markers and the surrounding terrain surface. This image data is stored together with metadata. A computing unit will calculate from the image data and the metadata the position of the settlement plate in the reference position. The deformation of the underlying dike body and outer shape and size of the terrain of the dyke body will be determined by photogram-metric computations of the image data, whereby the positions of the settlement plates serve as points of reference.

[12] This embodiment has the advantage that fewer settlement plates are needed to monitor a dyke of terrain.

Reference: DellalaT 03 — 30.06.2023 -3-

Brief description of the drawings

[13] The present invention will be discussed in more detail below, with reference to the attached drawings, in which:

[14] Fig. 1 depicts a monitoring system for a dyke according to the first embodiment of the invention.

[15] Fig. 2 depicts a monitoring system for a dyke according to the second embodiment of the invention.

Detailed description of preferred aspects of the invention

[16] In a first embodiment of the present invention, see Fig. 1, settlement plates 12 being installed in the region of the dyke 7 to be monitored in a regular pattern. In this first embodiment, the settlement plates are placed essentially equidistant to one another over the expanse of the dyke to be monitored. Preferably the settlement plates are installed along lines 10 were cross sections of the dyke need to be measured.

[17] The settlement plates are provided with a unique visual marker 3, 4 each, on top of the settlement plate’s rod. Said markers being unique in the sense that every marker is equipped with a unique identifying pattern, such a QR code, barcode or ring code. Said identifying patter will be used in the analysis to identify the individual settlement plate and its position on the terrain.

[18] Settlement plates at strategically important reference positions, such as the outer corners of the area to be monitored, will additionally be equipped with stand-alone GNSS receivers 11 on top of the settlement rods. Those GNSS receiver determine their own position on a regular basis and serve references for the monitoring system. Receivers of this kind are known from ntips:/ideltaiot.nlien/deltacube-2/.

[19] Those settlement plates being equipped with said GNSS receivers are also provided with a specific unique marker 3 known as Ground Control Point (GCP) marker. The GCPs will serve as a reference points for the determination of all other settlement plates and their positions.

[20] In addition to the GNSS receivers at the GCPs, the system may be provided with a GNSS reference station 2 installed on a stable object, outside the terrain to be monitored. This allows for a truly absolute fixed reference for all measurements.

[21] The monitoring of the settlement plate positions will be performed by at least one UAV 5 in regular intervals during flights over the terrain to be monitored. The at least one UAV is parked at a “Drone in a Box” control station. Said control station may be able to electrically charge the

UAV. The control station may further be provided with a data connection to the UAV when the

UAV is parked at the control station. At the control station, a redetermined flightpath 6 may be communicated to the UAV before the flight of the at least one UAV.

[22] The person skilled in robotics will understand that such a flightpath is optional. Often in robotics, randomly generated motions are used, for example in the control of some robotic vacuum cleanser. Random paths and flightpaths have the advantage of avoiding systematic errors during a measurement. In the scenario of the randomly generated flightpath, the at least one UAV will recognize the boundaries of the terrain to be measure by the GCP markers.

Reference: DellalaT 03 — 30.06.2023 -4-

[23] During its flight on a flightpath, the at least UAV records image data from the visual markers and stores said image data together with metadata in a data storage. Said metadata may contain the position of the at least one UAV, the attitude of the at least one UAV, the altitude of the at least one UAV, the velocity of the at least one UAV and more. The attitude data of the at least one UAV may contain pitch, roll and yawl information.

[24] Since the at least one UAV stores all metadata, a randomly generated flightpath will be recorded in the metadata, which allows for precise determination of the settlement plates’ locations.

[25] Once the at least one UAV is about to concluded the flight, the at least one UAV retums to the “Drone in a Box” control station. Here the drone may charged and prepared for the next flight. Also at the control station, image data and metadata may be offloaded from the UAVs data storage.

[26] A computing unit calculate from the stored image data and metadata the position of each settlement plate and thereby determine the deformation of the underlying dike body and outer shape and size of the terrain of the dyke body. Such calculations may be performed hy triangulation of any other methods suitable. Such methods are widely known in the field of surveying and are therefore not discussed in detail in this document.

[27] The system of the present invention can monitor a large area without the need of installing any infrastructure. The size of the area is limited by the capabilities of the at least UAV in terms of endurance and speed only. The UAV may be programmed with a predetermined flight path, such that communications to a control station is not necessary, which would allow the at least one UAV to reach beyond the radio horizon of the control station. Most UAVs are presently provided with a “auto home” function, which utilizes GNSS signals to determine the home position. Said home position is the position of the control station. Thereby, the at least one UAV would always be able to return to the control station, even in the control station of beyond the radio horizon of the UAV.

[28] In order to increase the surface area to be monitored, a plurality of UAVs may be employed. Each of the plurality of UAVs having its own docking station one or more control stations.

[29] While, as previously described, the image data and metadata may be offloaded when the drone is parked at the control station, offloading of the image data and metadata may also happen during the flight, either with a direct communication link to the control station or by means of wireless communication technology such as 3G, 4G and 5G. When using the latter, the UAV can leave the communication radius of its control station, while still be able to offload data in essentially real time.

[30] In a second embodiment, see Fig. 2, settlement plates are only installed on particular important strategic reference positions in the terrain to be monitored. The settlement plates are provided with particular Geodetic Top layer barcode Control Point (TCP) markers 9.

[31] In the second embodiment, strategically important positions, such as the outer corners of the area to he monitored, may be equipped with settlement plates which are additionally equipped

Reference: DellalaT 03 — 30.06.2023 -5- with stand-alone GNSS receivers 11 on top of the settlement rods. Those GNSS receiver determine their own position on a regular basis and serve as references for the monitoring system.

[32] Those settlement plates being equipped with said GNSS receivers are also provided with a specific unigue marker 3 known as Ground Control Point (GCP) marker. The GCPs will serve as a reference points for the determination of all other settlement plates and their positions.

[33] In addition to the GNSS receivers at the GCPs, the system may be provided with a GNSS reference station 2 installed on a stable object, outside the terrain to be monitored. This allows for a truly absolute fixed reference for all measurements.

[34] In the second embodiment of the present invention, a few settlement plates are installed in the terrain to be monitored. Said settlement plates are equipped with visual markers 9 essentially at a minimum height over surface of the terrain to be monitored. Said markers 9 are mounted in an adjustable manner on the settlement rod, such that the height of the visual marker can be changed during the monitoring campaign. Said markers serve as Geodetic Top layer barcode Control Point (TCP).

[35] The monitoring of the settlement plate positions will be performed by at least one UAV 5 in regular intervals during flights over the terrain to be monitored. The at least one UAV is parked at a “Drone in a Box” control station. Said control station may be able to electrically charge the

[36] The person skilled in robotics will understand that such a flightpath is optional. Often in robotics, randomly generated motions are used, for example in the control of some robotic vacuum cleanser. Random paths and flightpaths have the advantage of avoiding systematic errors during a measurement. In the scenario of the randomly generated flightpath, the at least one UAV will recognize the boundaries of the terrain to be measure by the GCP markers.

[37] The monitoring of the terrain will be performed by at least one UAV in regular intervals. In the second embodiment, the at least UAV records images from the visual markers and the surrounding terrain surface. Said image data of the terrain surface and the visual makers is stored together with metadata.

[38] Once the at least one UAV is about to concluded the flight, the at least one UAV returns to the “Drone in a Box" control station. Here the drone may charged and prepared for the next flight. Also at the control station, image data and metadata may be offloaded from the UAV’s data storage.

[39] A computing unit will calculate from the image data and the metadata the position of the settlement plate in the reference position. The shape and size (deformation) of the terrain or dyke will be determined by photogrammetric computations of the image data. In these calculations, the positions of the settlement plates, known as TCP, and the positions of the GNSS receivers, known as GCP, serve as points of reference for the photogrammetric evaluation of the image data.

Reference: DellalaT 03 — 30.06.2023 -6-

[40] Photogrammetric methods to determine the shape and size (deformation) of terrain or man-made structures are known . Patent document WO2022173285A1 discloses a system and method for monitoring quay walls. The system is arranged to record image data of a quay wall.

The image data is recorded from a plurality of angles, providing a plurality of perspectives, creating multi-perspective image data. The multi-perspective image data is analysed to determine deformations and/or displacement of the quay wall to be monitored. The present application utilizes this method to monitor dykes and similar terrain.

[41] An additional advantage may be obtained in the second embodiment of the present invention, when a swarm of UAVs is deployed. This increases the amount of multi-perspective image data for the above mentioned calculation, thereby increasing the accuracy of the monitoring.

[42] The second embodiment has the further advantage that fewer settlement plates are needed to monitor a dyke of terrain. Since settlement plates cannot be removed if the monitoring campaign has concluded, less material is left to pollute the terrain. Further, with fewer settlement plates to be installed on the terrain, according to the second embodiment of the present invention, a monitoring campaign will be commissioned in a relationally shorter time compared to the commissioning of a monitoring campaign, according to the first embodiment of the present invention.

List of reference signs 1 Drone in the box control station 2 GNSS sensor reference station. 3 GNSS sensor "Ground Control Point” (GCP) 4 Geodetic Settlement barcode Measurement Point (SMP) 5 Autonomous drone (UAV). 6 Flightpath UAV 7 Dyke Body 8 Waterway 9 Geodetic Top layer barcode Control Point (TCP) 10 Cross section 11 GNSS receiver 12 Settlement plate rod

Claims

Conclusions 1 A system for terrain surveillance, the system consists of: at least one control station (1), at least one reference station (2), a number of beacons (12) and at least one unmanned aerial vehicle UAV (5).

2 The system of claim 1, wherein the bag beacons are provided with visual markings (3, 4, 9).

3 The system of claim 2, wherein the pocket beacons (12) are arranged in a regular pattern.

4 The system of claim 3, wherein the settlement beacons are provided with a Geodetic Settlement barcode Measurement Point (SMP) (4).

5 The system of claim 2, wherein the bag beacons are installed at specific locations.

6 The system of claim 5, wherein the bag beacons are provided with a Geodetic Top layer barcode Control Point (TCP) (9).

7 The system of claims 2 to 6, wherein some of the pocket beacons are provided with GNSS receivers (11).

8 The system of claim 7, wherein the pocket beacons provided with a GNSS receiver are provided with a visual marker indicating a Ground Control Point (GCP) (3).

9 The system of claim 1, wherein the reference station is equipped with a GNSS receiver.

10 The system of claim 1, wherein the control station is equipped with infrastructure to park and charge the UAV.

11 The system of claim 1, wherein the control station and the reference station are located in the same building.

12 The method of monitoring a site, the method comprising the steps of: providing at least one control station (1), providing at least one reference station (2), providing a plurality of location plates (12) and providing at least one unmanned aerial vehicle UAV (5).

The method according to claim 12, wherein the bag beacons are provided with visual markers (3, 4, 9).

The method of claim 13, wherein the pocket beacons (12) are arranged in a regular pattern.

15 The method of claim 14, wherein the pocket beacons are provided with a Geodetic Settlement barcode Measurement Point (SMP) (4).

16 The method of claim 13, wherein the bag beacons are installed at specific locations.

17 The method according to claim 16, wherein the bag beacons are provided with a Geodetic Top layer barcode Control Point (TCP) (9).

18 The method according to claims 13 to 17, wherein some of the pocket beacons are provided with GNSS receivers (11).

19 The method according to claim 18, wherein the bag beacons provided with a

GNSS receiver shall be equipped with a visual marker indicating a Ground Control Point GCP (3).

The method according to claim 12, wherein the reference station is equipped with a GNSS receiver.

21 The method of claim 12, wherein the control station is equipped with

20 infrastructure to park and charge the UAV.

22 The method according to any of claims 12 to 15 and 18 to 21, wherein the shape and size (deformation) of the terrain is determined and monitored by evaluating from image data and metadata the position of the visual markers for the Geodetic Settlement barcode Measurement Points (SMP) (4) relative to the positions of the reference station (2) and the visual marker indicating a Ground Control Point (GCP) (3), using suitable methods such as triangulation.

23 The method according to any of claims 12, 13 and 16 to 21, wherein the shape and magnitude (deformation) of the terrain is determined and monitored by evaluating from image data and metadata the shape of the terrain relative to the positions of the Geodetic Top layer barcode Control Point (TCP) (9), the reference station (2) and the visual marker indicating a ground control point (GCP) (3), the evaluation of the image data being performed by a suitable photogrammetric method.