Displacement Observation System

Abstract

To provide a displacement observation system that can suppress communication costs and ensure robustness of observation data even if displacement observation is performed using a large number of mobile stations.SOLUTION: A displacement observation system 1 includes: a reference station 2; a plurality of mobile stations 3; and a positioning server 5 that measures displacement of a location of each of the mobile stations 3 on the basis of observation data from the reference station 2 and each of the mobile stations 3. The displacement observation system 1 further includes: a plurality of relay stations 4, which temporarily stores mobile station observation data D2 of the mobile stations 3 in a mobile station group GP, grouped into the mobile station group GP consisting of the plurality of mobile stations 3, and transmits the temporarily stored mobile station observation data D2 to the positioning server 5 in a lump every predetermined time. The positioning server 5 synchronizes the mobile station observation data D2 transmitted from the relay stations 4 and reference station observation data D1 transmitted from the reference station 2 to perform positioning operations to determine displacement of the position of each of the mobile stations 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a displacement observation system that can reduce communication costs and ensure the robustness of observation data even when performing displacement observation using a large number of mobile stations. [Background technology]

[0002] Positioning using the Global Navigation Satellite System (GNSS) is used in a variety of situations, including monitoring the dynamics of slopes, detecting the shaking of high-rise buildings due to long-period seismic motion, and grasping the positions of people and moving objects. Among these, for dynamic monitoring of embankments and cuts at construction sites and slopes on expressways, GNSS equipment is installed in areas of the slope that are at risk of being enveloped, and the displacement of each GNSS equipment is managed according to prescribed management standards. For monitoring the dynamics of slopes using GNSS equipment, positioning is required in quasi-real time, for example, every 3 hours or once a day.

[0003] Interferometric positioning (RTK: Real Time Kinematic GPS) uses carrier phase as the distance between a satellite and a moving object. Carrier phase has higher distance measurement accuracy than the pseudo distance used by GPS positioning, and allows positioning to within a few mm to a few cm. Interferometric positioning is generally a method of determining the relative position of a mobile station with respect to a fixed reference station whose coordinates are known. Interferometric positioning can eliminate clock errors by determining the double phase difference (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-119818 A Summary of the Invention [Problem to be solved by the invention]

[0005] When slope dynamics observations are performed in quasi-real time using a large number of mobile stations, each mobile station transmits observation data in real time to a positioning server that performs positioning calculations. However, this results in a huge amount of communication traffic, which increases communication costs and creates the problem that there is a high possibility that observation data will be lost due to wireless communication failures, etc.

[0006] The present invention has been made in consideration of the above, and aims to provide a displacement observation system that can reduce communication costs even when performing displacement observation using a large number of mobile stations, and ensure the robustness of the observation data. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the present invention provides a displacement observation system comprising a reference station whose position is known and which receives satellite signals from a plurality of positioning satellites, a plurality of mobile stations which receive satellite signals from a plurality of positioning satellites, and a positioning server which measures the displacement of the position of each mobile station based on observation data from the reference station and each mobile station, the system further comprising a plurality of relay stations which temporarily store mobile station observation data of mobile stations in a mobile station group which is composed of a plurality of mobile stations, and transmit the temporarily stored mobile station observation data to the positioning server in a lump at predetermined intervals, the positioning server synchronizing the mobile station observation data transmitted from the relay stations with the reference station observation data transmitted from the reference station, and performing positioning calculations to measure the displacement of the position of each mobile station.

[0008] In the above-mentioned invention, the relay station compresses the mobile station observation data of each mobile station received within the predetermined time period and transmits the compressed data to the positioning server.

[0009] In the above-mentioned invention, the present invention is characterized in that the mobile stations in each mobile station group and the relay station are connected by wire.

[0010] In the above-mentioned invention, the mobile stations in the mobile station group are disposed in a dispersed manner on the surface of the earth where displacement is to be observed. Effect of the Invention

[0011] According to the present invention, even when displacement observation is performed using a large number of mobile stations, communication costs can be reduced and the robustness of observation data can be ensured. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram showing the configuration of a displacement observation system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of a mobile station and a relay station arranged on a ground surface where a slope has been constructed. [Diagram 3] FIG. 3 is a diagram showing an outline of the configuration of a mobile station. [Figure 4] FIG. 4 is a sequence diagram showing a displacement observation processing procedure performed by the displacement observation system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0014] <System configuration> Fig. 1 is a block diagram showing the configuration of a displacement observation system 1 according to an embodiment of the present invention. As shown in Fig. 1, in the displacement observation system 1, a reference station 2 and a plurality of mobile stations 3 are connected to a positioning server 5. The reference station 2 transmits reference station observation data D1 to the positioning server via a network N. Each mobile station 3 transmits mobile station observation data D2 to the positioning server 5 via a relay station 4 and the network N. The positioning server 5 performs positioning calculations for each mobile station 3 based on the received reference station observation data D1 and mobile station observation data D2.

[0015] The reference station 2 has a receiver 21 and an antenna 22, receives satellite signals from multiple positioning satellites S of the GNSS 100, and transmits the received satellite signals as reference station observation data D1 to the positioning server 5. Meanwhile, each mobile station 3 has a receiver 31 and an antenna 32, receives satellite signals from multiple positioning satellites S of the GNSS 100, and transmits the received satellite signals as mobile station observation data D2 to the relay station 4 of its own mobile station group GP.

[0016] Here, each relay station 4 temporarily stores mobile station observation data D2 of the mobile stations 3 in the mobile station group GP, which is grouped into a mobile station group GP consisting of a plurality of mobile stations 3, and transmits the temporarily stored mobile station observation data D2 to the positioning server 5 all at once at predetermined time intervals. In this embodiment, eight mobile stations 3 are connected to one relay station 4 in each mobile station group GP. In each mobile station group GP, the relay station 4 and each mobile station are connected by wire, for example, with a LAN cable. Note that the number of mobile stations 3 in each mobile station group GP is set to eight for the sake of processing by the relay station 4, but is not limited to this. Also, the number of mobile stations 3 in each mobile station group GP may be different. Also, the predetermined time is set to about several minutes to several tens of minutes.

[0017] Each relay station 4 has a control unit 41, a temporary storage unit 42, and a communication processing unit 43. The control unit 41 connects each mobile station 3 in its own mobile station group GP by wire, stores mobile station observation data D2 sent from each mobile station 3 in the temporary storage unit 42, and after a predetermined time has elapsed, compresses the mobile station observation data D2 stored in the temporary storage unit 42 by ZIP or the like, and transmits the compressed data collectively to the positioning server 5 via the communication processing unit 43 and the network N. The control unit 41 is, for example, an ultra-compact single board computer such as Raspberry Pi (registered trademark) used in IOT, and is equipped with a real-time operating system.

[0018] The positioning server 5 synchronizes the mobile station observation data D2 transmitted from the relay station 4 with the mobile station observation data D2 of each mobile station 3 transmitted from each relay station 4, and performs positioning calculations for each mobile station 3 to measure the displacement of the position of each mobile station 3.

[0019] The positioning server 5 includes a control unit 51 and a storage unit 54. The control unit 51 includes a positioning calculation unit 52 and a data conversion unit 53. The storage unit 54 stores the reference station observation data D1, the mobile station observation data D2, and the positioning result data D3. The positioning server 5 may be placed on a cloud.

[0020] Since the reference station observation data D1 and each mobile station observation data D2 are not sent simultaneously, the positioning calculation unit 52 performs positioning calculation using the RTK positioning method when the reference station observation data D1 and each mobile station observation data D2 are received.

[0021] The data conversion unit 53 converts the positioning data calculated by the positioning calculation unit 52 into a plane Cartesian coordinate system to generate positioning result data D3, and stores the data in the storage unit 54.

[0022] <Example of placement of mobile stations and relay stations> Fig. 2 is a diagram showing an example of mobile stations 3 and relay stations 4 arranged on a ground surface 101 where slope construction has been performed. In Fig. 2, 16 mobile stations 3 are distributed on the ground surface 101, and two mobile station groups GPa and GPb are formed, with eight mobile stations 3 in each mobile station group. Relay stations 4a and 4b are provided in each mobile station group GPa and GPb, respectively, and the eight mobile stations 3 in each mobile station group are connected by a LAN cable L.

[0023] <Overview of the mobile station> Fig. 3 is a diagram showing an outline of the configuration of the mobile station 3. As shown in Fig. 3, the mobile station 3 has an antenna 32 and a receiver 31 covered in a housing 34, and is connected to the relay station 4 via a LAN cable L from the housing 34. A stake 35 made of resin or the like is provided at the bottom of the housing 34, and the mobile station 3 is installed upright on the ground surface 101 by inserting the stake 35 into the ground surface 101.

[0024] <Displacement observation processing> Fig. 4 is a sequence diagram showing the displacement observation processing procedure by the displacement observation system 1. As shown in Fig. 4, first, a plurality of mobile stations 3 connected by wire to the relay station 4 transmit mobile station observation data D2 to the relay station 4 (step S110). On the other hand, the reference station 2 transmits reference station observation data D1 to the positioning server 5 (step S120).

[0025] Thereafter, the relay station 4 temporarily stores the received mobile station observation data D2 (step S120). Furthermore, the relay station 4 determines whether or not a predetermined time has elapsed (step S140), and if the predetermined time has not elapsed (step S140: No), the relay station 4 proceeds to step S120, and if the predetermined time has elapsed (step S140: Yes), the relay station 4 compresses the temporarily stored mobile station observation data D2 and transmits the compressed mobile station observation data D2 to the positioning server 5 in a lump (step S150).

[0026] The positioning server 5 judges whether the mobile station observation data D2 and the reference station observation data D1 have been uploaded (step S160). If they have not been uploaded (step S160: No), this judgment process is repeated. If they have been uploaded (step S160: Yes), the RTK positioning calculation process is performed (step S170). After that, the positioning data calculated by the positioning process is converted into a plane orthogonal coordinate system (step S180), and the converted positioning result data D3 is stored in the storage unit 54 (step S190), and this process is terminated. The above process is repeated. In step S130, the reference station observation data D1 is uploaded, but it is preferable that the positioning server 5 downloads the reference station observation data D1 from the reference station 2. In this case, the positioning server 5 temporarily stores the downloaded reference station observation data D1, and performs the positioning calculation process when the data is transmitted from the relay station 4 in a lump. The positioning calculation by the positioning server 5 is performed when the transmission from all relay stations 4 in a lump is completed.

[0027] In this embodiment, the mobile station observation data D2 of each mobile station 3 is not directly transmitted to the positioning server 5, but the relay station 4 compresses the mobile station observation data D2 of multiple mobile stations 3 and transmits it collectively to the positioning server 5, thereby reducing the amount of communication between the mobile station 3 and the positioning server 5, thereby reducing communication costs and simplifying the configuration of each mobile station 3. Furthermore, because the amount of communication between the mobile station 3 and the positioning server 5 is reduced, the probability of missing mobile station observation data due to communication failures or the like is reduced, and the robustness of the mobile station observation data can be ensured.

[0028] In addition, each configuration illustrated in the above embodiment is a functional schematic, and does not necessarily have to be physically configured as illustrated. In other words, the form of distribution and integration of each device and component is not limited to that illustrated, and all or a part of them can be functionally or physically distributed and integrated in any unit according to various usage conditions, etc. [Explanation of symbols]

[0029] 1. Displacement monitoring system 2 Reference station 3 Mobile Station 4, 4a, 4b Relay Station 5 Positioning Server 21,31 Receiver 22,32 Antenna 34 Case 35 stake 41,51 Control section 42 Temporary storage 43 Communication processing unit 52 Positioning calculation unit 53 Data Conversion Section 54 Memory section 101 Ground surface D1 Reference station observation data D2 Mobile station observation data D3 Positioning result data GP, GPa, GPb Mobile Station Group L LAN cable N Network S Positioning satellite

Claims

1. a reference station having a known position that receives satellite signals from a plurality of positioning satellites; A plurality of mobile stations receiving satellite signals from a plurality of positioning satellites; a positioning server that measures the displacement of each mobile station based on observation data from the reference station and each mobile station; A displacement observation system comprising: a plurality of relay stations which temporarily store mobile station observation data of mobile stations in a mobile station group which is composed of a plurality of mobile stations, and transmit the temporarily stored mobile station observation data to the positioning server at a time interval; A displacement observation system characterized in that, when the mobile station observation data transmitted from the relay station and the reference station observation data transmitted from the reference station are obtained, the positioning server synchronizes the data and performs positioning calculations using the RTK method to measure the displacement of the position of each mobile station.

2. 2. The displacement observation system according to claim 1, wherein the relay station compresses the mobile station observation data of each mobile station received within the predetermined time period and transmits the compressed data to the positioning server.

3. 3. The displacement observation system according to claim 1, wherein the mobile stations in each mobile station group and the relay station are connected by wire.

4. 4. The displacement observation system according to claim 1, wherein each of the mobile stations in the mobile station group is distributed over the surface of the earth that is the subject of displacement observation.

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