Positioning system

Abstract

To solve the conventional problems, that is, to provide a positioning system that can determine the coordinates of an object to be positioned with higher accuracy than conventional technology by using edge-based RTK positioning.SOLUTION: The positioning system of the present invention is a system for locating the position of an object by using a positioning satellite, and is equipped with an observation station, a base station, communication means, and coordinate calculation means. The coordinate calculation means installed in the observation station is means for performing baseline analysis based on the edge observation data acquired by the observation station and the base station observation data received by the communication means, and for determining target coordinates of the target to be positioned based on real-time kinematic positioning. The coordinate calculation means calculates the target coordinates based on the reception time related to the base station observation data and the edge observation data related to the same reception time.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a technology relating to satellite positioning, and more specifically, to a positioning system that determines the displacement of an observation point placed at an object to be positioned. [Background technology]

[0002] It has been pointed out that the construction infrastructure (hereafter referred to as "construction infrastructure"), which was developed intensively during the period of high economic growth, is already considerably deteriorated. In 2014, the "Proposal for full-scale implementation of measures against deterioration of roads (Council for Social Capital Development)" was compiled, and citing the example of the Sasago Tunnel in 2012, it sounded a warning that "in the near future, it will lead to fatal incidents involving human lives and social facilities, such as the collapse of bridges," and strongly advocated the importance of maintaining and managing construction infrastructure. In this context, the government promulgated a ministerial ordinance amending part of the Road Act Enforcement Regulations, and formulated regular inspection guidelines that show specific construction infrastructure inspection methods, areas to look for in major abnormalities, and photos of judgment examples. For example, with regard to bridges, the target is bridges with a length of 2.0 m or more, which is said to amount to about 700,000 bridges, and the initial inspection is to be carried out within two years of the start of service, and regular inspections are to be carried out once every five years thereafter.

[0003] Typical examples of construction infrastructure include road structures such as tunnels and bridges, as well as road slopes. The total length of roads in use in Japan exceeds 1.2 million km, including approximately 9,000 km of national expressways, and it is said that approximately 30% of these roads are located in mountainous areas, which means that a large number of road slopes need to be maintained.

[0004] Regular inspections are essential for the proper maintenance of road slopes, but in the past, they tended to be carried out only when large-scale slope disasters occurred, such as the bus accident that fell off the Hida River on National Highway 41 in 1968, the landslide accident on National Highway 56 in 1981, and the rockslide accident on National Highway 305 in 1989. As a result, the Hida River bus accident, which caused particularly severe damage, prompted the institutionalization of road disaster prevention inspections and advance traffic restrictions. Also, in 1996, an 11,000m2 slope inspection was carried out near the entrance to the Toyohama Tunnel on National Highway 229. 3 Following the rockslide, emergency road disaster prevention inspections were carried out across the country that year.

[0005] In recent years, road slope inspections are conducted periodically (once every five years as a rule), and are carried out under a systematic system in which the results of the inspections are recorded for each slope. For example, a stability survey sheet was introduced after the Naruto Rockfall Accident on National Route 11 in 1990, and since 1996, when a comprehensive road disaster prevention inspection was carried out, a system has been introduced in which an overall evaluation consisting of "measures required," "medical record response," and "no measures required" is recorded on the stability survey sheet.

[0006] By inspecting road slopes in this way, it is possible to grasp the condition of each slope and to confirm the policy for subsequent countermeasures. However, as mentioned above, there are a large number of road slopes that require maintenance, so it is not realistic to conduct full-scale inspections frequently. In addition, the current road slope inspections are based on the visual evaluation of the inspector, which means that the results are qualitative and vary depending on the inspector's experience and knowledge, which is a problem that can be pointed out.

[0007] In road slopes that are at risk of collapse or that show signs of landslides, in addition to regular inspections, observations to monitor their movement (so-called dynamic observations) are sometimes conducted. For example, in slopes that show signs of landslides, observations using extensometers and punching plates, observations using borehole inclinometers, and measurements of ground surface displacement have been carried out. However, observations using extensometers and punching plates are only effective if they are installed over the entire landslide boundary (especially the head), and borehole extensometers are only effective if the depth of the landslide surface is accurately estimated, and there are problems with installing them in multiple locations, as they are costly. In other words, these observation methods can only be carried out on slopes where the landslide surface can be estimated to some extent, and cannot be adopted for slopes where the landslide surface cannot be estimated or slopes that are at risk of collapse.

[0008] In contrast, ground surface displacement measurement determines the three-dimensional coordinates of many observation points installed on a slope and monitors the movement of the slope by detecting displacement over time, making it possible to directly identify abnormalities, and has the advantage that its effectiveness does not depend on the location of the instrument, as does the extensometer or borehole inclinometer.However, if the observation points are located manually using a total station or similar, it requires a lot of effort and cost.

[0009] In view of this, Patent Documents 1 and 2 disclose inventions for monitoring slopes by performing dynamic observation using a global navigation satellite system (GNSS).

[0010] By utilizing the inventions disclosed in Patent Documents 1 and 2, it is possible to monitor not only slopes that are at risk of collapse or show signs of a landslide, but also slopes where no particular movement is observed, and furthermore, it is possible to directly and quantitatively grasp abnormalities, and has the advantage of not requiring the large effort and cost required by total station measurements.

[0011] By the way, the methods for obtaining the coordinates of an observation point using GNSS positioning are divided into two categories: "single point positioning methods (absolute single point positioning and differential positioning)" and "interferometric positioning methods." Of these, it is known that the interferometric positioning method can obtain results with higher accuracy. Interferometric positioning methods include static positioning and kinematic positioning. Of these, static positioning is a method in which multiple receivers observe four or more satellites. It can obtain the coordinates of an observation point with high accuracy (horizontal accuracy of about 5 to 10 mm), but it has the disadvantage that it requires a long observation time (for example, one hour), and therefore takes a long time to obtain results. On the other hand, kinematic positioning is less accurate than static positioning (horizontal accuracy of about 20 to 30 mm), but it allows observation in a short time (for example, 120 to 3,600 points / hour), and therefore it can detect changes in the observation target quickly.

[0012] Real-time kinematic positioning (RTK positioning) is the mainstream method of kinematic positioning used to monitor slopes. This RTK positioning is a method of performing baseline analysis using observation data acquired from an observation station installed on the observation target (e.g., a slope) and observation data acquired from a reference station installed at a location distant from the observation target, to determine the coordinates and displacement of the observation point (i.e., the observation station). Conventionally, the "cloud method" in which baseline analysis is performed on a cloud server has been widely used. In other words, the observation data from the observation station and the reference station are sent to the cloud server, and the results of the baseline analysis are provided to a specified user.

[0013] In recent years, with the advancement of computer performance and miniaturization, the "edge method" of performing baseline analysis at the observation station has also been adopted. As disclosed in Patent Document 3, this edge method is a method in which observation data from a reference station is transmitted to the observation station and baseline analysis is performed on a device at the observation station. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] JP 2003-217054 A [Patent Document 2] JP 2017-203650 A [Patent Document 3] JP 2016-102789 A Summary of the Invention [Problem to be solved by the invention]

[0015] Usually, RTK positioning uses the latest observation data (i.e., the most recently received observation data), that is, the baseline analysis is performed using the latest observation data acquired by the observation station and the latest observation data acquired by the reference station. For example, in the case of RTK positioning using the edge method, as shown in Patent Document 3, the baseline analysis is performed using the latest observation data acquired by the observation station and the latest of the observation data sent from the reference station to determine the coordinates and displacement of the observation point.

[0016] However, it takes time for the observation data to reach the observation station from the reference station. In other words, when comparing the "latest observation data acquired by the observation station" and the "latest observation data sent from the reference station", their reception times are different, and more specifically, the observation data of the reference station is received at an earlier time by the amount of time it took to transmit. For example, in Figure 6, the reference station and the observation station each receive a signal from the satellite every second, and it takes one second for the observation data to reach the observation station from the reference station. Then, the baseline analysis is performed using the latest observation data related to the observation station and the latest observation data related to the reference station. For example, the baseline analysis is performed using the observation data Ds_04 received by the observation station at 10:35:04 and the observation data Dm_03 received by the reference station at 10:35:03. In this way, in the conventional technology, the baseline analysis was performed using observation data originating from different reception times.

[0017] As a result of repeated testing and investigation, the inventors of the present application found that when observation data derived from different reception times is used, the analysis results (i.e., coordinate values ​​and displacement amounts) vary greatly, i.e., the accuracy and reliability decrease.

[0018] The object of the present invention is to solve the conventional problems, that is, to provide a positioning system that can determine the coordinates of an object to be positioned with higher accuracy than conventional technology by edge-based RTK positioning. [Means for solving the problem]

[0019] The present invention focuses on the fact that the reception time of the observation data from the observation station is aligned with the reception time of the observation data from the reference station, and then baseline analysis is performed at the observation station, and is an invention based on an idea that has not been seen before.

[0020] The positioning system of the present invention is a system for positioning a target using a positioning satellite, and includes an observation station, a base station, a communication means, and a coordinate calculation means. The observation station located at the target acquires edge observation data by receiving radio waves from the positioning satellite, and the base station located at a location different from the target acquires base station observation data by receiving radio waves from the positioning satellite. The communication means provided at the observation station is a means for receiving the base station observation data acquired by the base station. The coordinate calculation means provided at the observation station is a means for performing baseline analysis based on the edge observation data acquired by the observation station and the base station observation data received by the communication means, and for determining the target coordinates of the target based on real-time kinematic positioning. The coordinate calculation means determines the target coordinates based on the reception time related to the base station observation data and the edge observation data related to the same reception time.

[0021] The positioning system of the present invention may further include a displacement calculation means arranged in the object to be positioned. This displacement calculation means is means for calculating an object displacement related to the object to be positioned based on object coordinates at two times.

[0022] The positioning system of the present invention may further include an error processing means for determining a corrected displacement by performing error processing on a plurality of target displacements.

[0023] The positioning system of the present invention can also be configured to measure the ground such as a slope. In this case, the error processing means is disposed at a location different from the target to be measured. The error processing means receives the target displacement transmitted by the communication means, and calculates a corrected displacement based on the received multiple target displacements. The error processing means is a means for determining a corrected displacement by performing error processing on a plurality of target displacements.

[0024] The positioning system of the present invention may also be configured to measure the position of a moving body such as an automobile, etc. In this case, the displacement calculation means is disposed in the moving body. Effect of the Invention

[0025] The positioning system of the present invention has the following advantages. (1) The coordinates of the target can be determined with greater accuracy than conventional edge-based RTK positioning. (2) Because the edge method is adopted, it is not necessary to use a cloud server, and as a result, the position of the target object can be determined at low cost. (3) The use of RTK positioning enables observations to be made in a short period of time, and as a result, changes in the object of observation can be detected quickly. [Brief description of the drawings]

[0026] [Figure 1] 1 is a block diagram showing the main configuration of a positioning system according to the present invention; [Diagram 2] FIG. 1 is a model diagram for explaining a baseline analysis according to the present invention. [Diagram 3] FIG. 11 is a flow diagram showing the flow from receiving base station observation data to error processing. [Figure 4]FIG. 1(a) is a graph plotting one day's worth of target displacement obtained by conventional technology when there is a two-second difference in the reception time between the edge observation data and the base station observation data, FIG. 1(b) is a graph plotting one day's worth of target displacement obtained by conventional technology when there is a one-second difference in the reception time between the edge observation data and the base station observation data, and FIG. 1(c) is a graph plotting one day's worth of target displacement obtained by the present invention. [Diagram 5] Graph (a) is a plot of changes in target displacement in the north-south direction obtained by the conventional technology and the present invention over a period of approximately one month. Graph (b) is a plot of changes in target displacement in the east-west direction obtained by the conventional technology and the present invention over a period of approximately one month. Graph (c) is a plot of changes in target displacement in the vertical direction obtained by the conventional technology and the present invention over a period of approximately one month. [Figure 6] FIG. 1 is a model diagram for explaining conventional baseline analysis. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] An example of an embodiment of the positioning system of the present invention will be described with reference to the drawings. The present invention is a technology that can grasp the position coordinates and displacement of a "positioning target," and in particular, is a positioning system that employs RTK positioning by an edge method that performs baseline analysis using a device at an observation station. Here, the positioning target is an object whose position coordinates and displacement are to be measured, and various objects can be the positioning target, including "ground" such as natural slopes, cut slopes, or flat ground, as well as "fixed structures" such as bridges, dams, retaining walls, office buildings, and apartment buildings, and "moving objects" such as automobiles and pedestrians. For convenience, an example will be described in which a slope (natural slope, cut slope, embankment slope, etc.) is the positioning target.

[0028] 1 is a block diagram showing the main components of a positioning system 100 according to the present invention. As shown in this figure, the positioning system 100 according to the present invention is mainly composed of an observation station 110 and a base station 120, which are connected by wireless communication means, wired communication means, or mobile communication means such as 5G / 4G / LTE. The observation station 110 is placed on the object to be positioned (in this case, a slope), while the other base station 120 is placed at a location away from the slope, and can use, for example, a nearby electronic reference point.

[0029] The observation station 110 includes a communication means (hereinafter referred to as "edge communication means 111") for transmitting and receiving data to and from the base station 120, and a coordinate calculation means 112, and may further include a displacement calculation means 113, an edge receiver 115, observation data extraction means 116, power generation means 117, observation data storage means 118, and displacement data storage means 119. The base station 120 may further include a base station receiver 121 and a base station communication means 122. The positioning system 100 may further include a cloud server, in which case the error processing means 114 may be provided in the cloud server.

[0030] The coordinate calculation means 112, the displacement calculation means 113, the observation data extraction means 116, and the error processing means 114 can be manufactured as dedicated means, or a general-purpose computer device can be used. In other words, the processing of the various means is performed by making the computer device execute arithmetic processing according to a specified program. This computer device is equipped with a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), memories such as ROM and RAM, and some also include input means such as a mouse and a keyboard, and a display, and can be configured, for example, by a personal computer (PC) or a server.

[0031] The observation data storage means 118 and the displacement data storage means 119 can use a storage device of a general-purpose computer (for example, a personal computer) or can be constructed in a database server. When constructed in a database server, they can be placed in a local network (LAN: Local Area Network) or can be a cloud server that stores data via the Internet.

[0032] Below, each of the main elements constituting the positioning system 100 of the present invention will be described in detail.

[0033] (Receiver) The edge receiver 115 constituting the observation station 110 and the base station receiver 121 constituting the base station 120 are each used for GNSS positioning, that is, they are devices that receive radio waves (carrier waves) from positioning satellites ST. The edge receiver 115 is installed at multiple observation points planned on a slope (positioning target), while the other base station receiver 121 is installed at a base station 120 away from the slope. These edge receiver 115 and base station receiver 121 can simultaneously receive signals from four or more satellites and are capable of kinematic positioning (especially real-time kinematic positioning).

[0034] The edge receiver 115 acquires observation data (hereinafter referred to as "edge observation data") by receiving a carrier wave from the positioning satellite ST, and similarly, the base station receiver 121 acquires observation data (hereinafter referred to as "base station observation data") by receiving a carrier wave from the positioning satellite ST. The edge observation data is then stored in the observation data storage means 118 (Figure 1). For convenience, the time when the edge receiver 115 receives the carrier wave from the positioning satellite ST is referred to as the "edge reception time", and the time when the base station receiver 121 receives the carrier wave from the positioning satellite ST is referred to as the "base station reception time".

[0035] The power generation means 117 generates electricity to be supplied to the edge communication means 111, coordinate calculation means 112, displacement calculation means 113, edge receiver 115, and observation data extraction means 116 that constitute the observation station 110, and may be, for example, a solar power generation device. By installing the power generation means 117, the use of commercial power can be avoided, and furthermore, power distribution lines on the slope can be omitted, which is preferable in terms of scenery and maintenance. Of course, instead of the power generation means 117, a commercial power source may be used, or a rechargeable battery or a dry cell may be used.

[0036] (Method of extracting observed data) The observation data extraction means 116 constituting the observation station 110 is a means for extracting edge observation data according to the base station observation data acquired by the base station 120 (base station receiver 121). Hereinafter, the process of extracting edge observation data by the observation data extraction means 116 will be described in detail with reference to Figs. 2 and 3.

[0037] As described above, in the conventional technology, the latest edge observation data and the latest base station observation data were used, and therefore baseline analysis was performed using observation data with different reception times as shown in FIG. 6. In contrast, in the positioning system 100 of the present invention, as shown in FIG. 2, appropriate edge observation data is extracted from the edge observation data stored in the observation data storage means 118 and then baseline analysis is performed. That is, when the edge communication means 111 receives base station observation data from the base station 120 (Step 201 in FIG. 3), it queries the observation data storage means 118 for the base station reception time related to the base station observation data. The query-receiving observation data storage means 118 extracts edge observation data having the same time as the base station reception time or the closest edge reception time (Step 202 in FIG. 3). The timing at which the base station observation data extracts the edge observation data can be when the edge communication means 111 receives the base station observation data, or can be specified to be performed periodically at a predetermined period, or can be specified to be performed in response to an operator operation.

[0038] In this way, the edge observation data and base station observation data relating to the same (or similar) reception time can be combined by the observation data extraction means 116. Then, using the edge observation data and base station observation data that are so-called time-synchronized, it is possible to calculate the position coordinates (hereinafter simply referred to as "target coordinates") of the slope (particularly the observation point) as described below (Step 203 in FIG. 3), and it is possible to calculate the displacement (hereinafter simply referred to as "target displacement") of the slope (particularly the observation point) using the target coordinates at two different times (Step 204 in FIG. 3), and furthermore it is possible to obtain a corrected displacement (hereinafter simply referred to as "target displacement") by performing error processing on a plurality of target displacements.

[0039] (Coordinate calculation means) The coordinate calculation means 112 is a means for calculating the target coordinates of a slope (particularly an observation point) using edge observation data and base station observation data relating to the same (or similar) reception time (hereinafter referred to as "time-synchronized edge observation data and base station observation data.") In other words, the coordinate calculation means 112 finds the three-dimensional coordinates of the slope by performing real-time kinematic positioning based on the edge observation data and base station observation data.

[0040] (Displacement calculation means) The displacement calculation means 113 is a means for calculating the target displacement based on the target coordinates at two times on the slope (particularly the observation point). The displacement calculation means 113 can calculate the difference between the "initial (installation) target coordinates" and the "target coordinates related to the current positioning" as the target displacement, or the difference between the "target coordinates related to the previous positioning" and the "target coordinates related to the current positioning" as the target displacement. Since the target coordinates handled here are three-dimensional coordinates, the target displacement can also be obtained as a displacement vector having a magnitude (amount of displacement) and a direction (direction of displacement). The displacement calculation means 113 can be disposed in the observation station 110, or, depending on the circumstances, can be disposed in a place away from the observation station 110, such as a cloud server. The target displacement calculated by the displacement calculation means 113 is stored in the displacement data storage means 119 (FIG. 1).

[0041] (Error processing means) The error processing means 114 is a means for obtaining a "corrected displacement" by performing error processing on a plurality of target displacements. As a method for this error processing, various conventional methods can be adopted, such as the "population moving average method" and the "sidereal day difference method" shown in JP2017-203650A. The error processing means 114 is preferably provided at a location away from the observation station 110, such as a cloud server, and the edge communication means 111 is preferably configured to transmit the target displacement to the error processing means 114.

[0042] (Mobile) So far, an example has been described in which a slope is the target of positioning, but as already mentioned, the positioning system 100 can also target "fixed structures (bridges, etc.)" and "moving bodies (automobiles, etc.)". When a moving body is the target of positioning, the observation station 110 is naturally provided on the moving body, that is, the edge communication means 111, coordinate calculation means 112, edge receiver 115, and observation data extraction means 116 are provided on the moving body, and the displacement calculation means 113 is also located on the moving body. In this case, it is desirable that the timing at which the base station observation data extracts the edge observation data is when the edge communication means 111 receives the base station observation data (i.e., in real time).

[0043] (Test Results) 4 and 5 are diagrams showing the results of tests carried out by the inventors of the present application. Of these, FIG. 4 is a graph plotting one day's worth of target displacement, where (a) and (b) show the target displacement acquired by edge-based RTK positioning using conventional technology, and (c) shows the target displacement acquired by the present invention. In FIG. 4(a), there is a 2-second difference between the reception times of the edge observation data and the base station observation data (the base station reception time is older), and in FIG. 4(b), there is a 1-second difference between the reception times of the edge observation data and the base station observation data (the base station reception time is older). Also, FIG. 5 is a graph plotting the change in target displacement acquired by the conventional technology (first half) and the present invention (second half) over a period of about one month, where (a) shows horizontal displacement in the north-south direction, (b) shows horizontal displacement in the east-west direction, and (c) shows horizontal displacement in the vertical direction.

[0044] Looking at the "2 second delay" in Figure 4(a), there is a large overall variation, with some large jumps. Also, in the "1 second delay" in Figure 4(b), slight jumps are observed and the plots are more concentrated than the "2 second delay", but the variation is still not small. In contrast, in the "present invention" in Figure 4(c), no clear jumps are observed and the plots are more concentrated than the "1 second delay". As a result, it was confirmed that by performing analysis using time-synchronized edge observation data and base station observation data as in the present invention, it is possible to suppress the variation in the target displacement, i.e., it is possible to obtain highly accurate and stable target displacement.

[0045] In Fig. 5(a)-(c), the results of edge-based RTK positioning using conventional technology are shown before the "boundary period" (left side in the figure), and the results of the present invention are shown after the "boundary period" (right side in the figure). In the first half of the conventional technology, there is a 2-second difference between the reception time of the edge observation data and the base station observation data (the base station reception time is older). Looking at this figure, it can be seen that in the first half of the period related to the conventional technology, there are many jumps overall and the variation is large. On the other hand, in the second half of the period related to the present invention, the jumps are clearly reduced and the variation is also smaller. From these results, it was confirmed that the variation of the target displacement can be suppressed by analyzing using time-synchronized edge observation data and base station observation data as in the present invention, that is, a highly accurate and stable target displacement can be obtained. [Industrial Applicability]

[0046] The positioning system of the present invention can be used for various positioning targets, including fixed structures such as bridges, dams, retaining walls, office buildings, and apartment buildings, as well as moving objects such as automobiles and pedestrians, and is particularly suitable for use on slopes such as natural slopes, cut slopes, and embankment slopes. Considering that the present invention can prevent accidents caused by slopes such as collapses and landslides, and can detect abnormalities in construction infrastructure such as bridges in advance, it can be said that the present invention is not only applicable to industry, but is also expected to make a great contribution to society. [Explanation of symbols]

[0047] 100 Positioning system of the present invention 110 (Navigation System) Observation Station 111 (Positioning System) Edge Communication Means 112 (Positioning system) coordinate calculation means 113 (Positioning System) Displacement Calculation Method 114 (Positioning system) error processing means 115 Edge receiver (for navigation systems) 116 (Navigation System) Observation Data Extraction Means 117 (Positioning System) Power Generation Means 118 (of the positioning system) Observation data storage means 119 (of the positioning system) Displacement data storage means 120 (Positioning System) Base Station 121 (Positioning System) Base Station Receiver 122 (Positioning System) Base Station Communication Means ST positioning satellite

Claims

1. A system for locating a position of a positioning target using a positioning satellite, an observation station that is disposed in the positioning target and receives radio waves from the positioning satellite to obtain edge observation data; a base station that is disposed at a location different from the target to be positioned and that acquires base station observation data by receiving radio waves from the positioning satellite; a communication means provided in the observation station for receiving the base station observation data acquired by the base station; a coordinate calculation means provided in the observation station for performing a baseline analysis based on the edge observation data acquired by the observation station and the base station observation data received by the communication means to determine an object coordinate of the object to be positioned based on real-time kinematic positioning; the coordinate calculation means calculates the target coordinates based on a reception time related to the base station observation data and the edge observation data related to the same reception time; A positioning system comprising:

2. The method further includes a displacement calculation means arranged on the target to be positioned and calculating a target displacement related to the target to be positioned based on the target coordinates at two times.

2. The positioning system according to claim 1 .

3. The method further includes an error processing unit for performing error processing on the plurality of target displacements to obtain a corrected displacement.

3. The positioning system according to claim 2.

4. The positioning object is a ground including a slope, the error processing means is disposed at a location different from the location of the object to be positioned, The error processing means receives the target displacements transmitted by the communication means, and calculates the corrected displacements based on the received target displacements.

4. The positioning system according to claim 3.

5. the positioning object is a moving object, The displacement calculation means is disposed on the moving body, 3. The positioning system according to claim 2.

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