GNSS positioning system and GNSS positioning method

Abstract

To provide a GNSS positioning system in which errors of a receiver itself are reduced.SOLUTION: Provided is a GNSS positioning system 100 comprising an antenna 20 for receiving a positioning signal from a GNSS satellite, and a control computation unit 35 for calculating the location of center O of the antenna 20 on the basis of the positioning signal. The antenna 20 includes three small antennas 21a, 21b, 21c. The three small antennas 21a, 21b, 21c are arranged so as to form an equilateral triangle on a circle centering on the center O of the antenna 20. The control computation unit 35 calculates the respective positions of the three small antennas 21a, 21b, 21c from the respective positioning signals, and calculates the center of gravity G4 of a calculated triangle 42, with calculated positions of the three small antennas 21a, 21b, 21c as its vertices, as the center position of the antenna 20.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a GNSS positioning system and a GNSS positioning method for measuring a position by receiving ranging signals transmitted from GNSS (Global Navigation Satellite System) satellites such as GPS (Global Positioning System) satellites. [Background technology]

[0002] Conventionally, positioning using GNSS has been widely used. A GNSS receiver receives ranging signals from four or more GNSS satellites and performs positioning based on these ranging signals. Patent Document 1 discloses a GNSS positioning system that measures the coordinates of a measurement point using GNSS satellites. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-056013 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, causes of errors in GNSS positioning include satellite position deviations, satellite clock errors, propagation delays of ranging signals such as temperature, air pressure, and satellite position, as well as receiver errors. Receiver errors are caused by the presence of obstacles in the vicinity, antenna pinching, poor cable contact, and the accuracy of the receiver itself. Conventionally, one receiver is equipped with only one antenna, and if an error occurs in the antenna, there is no way to eliminate the error, and there has been a demand for the development of technology to reduce the receiver error itself.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a GNSS positioning system and a GNSS positioning method in which errors in the receiver itself are reduced. [Means for solving the problem]

[0006] In order to achieve the above object, a GNSS positioning system according to one embodiment of the present invention has the following configuration.

[0007] 1. A GNSS positioning system comprising an antenna that receives a ranging signal from a GNSS satellite and a control and calculation unit that calculates the position of the center of the antenna based on the ranging signal, wherein the antenna comprises three small antennas that are arranged to form an equilateral triangle on a circumference centered on the center of the antenna, and the control and calculation unit calculates the position of each of the three small antennas from the ranging signal received by each of the three small antennas, and calculates the center of gravity of a calculated triangle whose vertices are the calculated positions of the three small antennas as the position of the center of the antenna.

[0008] 2. In the configuration 1 above, it is also preferable that the configuration further includes a pole supporting the antenna, the distance from the tip of the pole to the center of the antenna is known, the pole is arranged so that the central axis of the pole passes through the center of the antenna, and the control and calculation unit calculates the coordinates of a measurement point abutting the tip held vertically.

[0009] 3. In the above configuration 1 or 2, it is also preferable that the control and calculation unit overlays the calculated triangle on the placement triangle so that the center of gravity of the calculated triangle coincides with the center of gravity of the placement triangle, which is an equilateral triangle formed by the three small antennas, adjusts the positions of the two triangles from the state in which the placement triangle and the calculated triangle are overlaid, finds a minimum-deviation placement in which the deviation of corresponding vertices is minimized, and calculates the center of gravity of the placement triangle resulting in the minimum-deviation placement as the position of the center of the antenna.

[0010] 4. In the above configuration 3, it is also preferable that the control and calculation unit performs weighting in accordance with the variation in the calculated position of each small antenna when calculating the minimum deviation arrangement.

[0011] 5. In configurations 2 and 3 and 4 which have configuration 2 above, it is also preferable that the control and calculation unit calculates the plane in which the small antenna is located based on the calculated position of each small antenna, thereby calculating the inclination of the pole, and calculating the coordinates of the measurement point taking into account the inclination.

[0012] 6. In the configurations 2 and 3 to 5 having the configuration of 2 above, it is also preferable that a display unit is further provided, and the control and calculation unit calculates a plane on which the small antennas are located based on the calculated positions of each small antenna, calculates the inclination of the plane, and displays the inclination on the display unit.

[0013] A GNSS positioning method according to another embodiment of the present invention has the following configuration.

[0014] 7. The method includes a receiver having an antenna for receiving ranging signals from GNSS satellites, the receiver having three small antennas arranged to form an equilateral triangle on a circumference centered on the center of the antenna, a step of receiving the ranging signals at each small antenna and converting them into electrical signals, a step of a computer calculating each small antenna's position from the ranging signals received by each small antenna, and a step of the computer calculating the position of the center of gravity of the three small antennas as the position of the center of the antennas.

[0015] 8. In the above configuration 7, it is also preferable that the configuration be equivalent to the above configurations 2 to 6. Effect of the Invention

[0016] According to the above aspect, it is possible to provide a GNSS positioning system and a GNSS positioning method in which errors in the receiver itself are reduced. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1A is a diagram showing a schematic configuration of a GNSS positioning system according to an embodiment of the present invention, and FIG. 1B is a diagram explaining the arrangement of antennas in a receiver constituting the system. [Diagram 2] FIG. 2 is a block diagram of the system. [Diagram 3] 4 is a flowchart of a position calculation method using the system. [Figure 4] 13(A) to 13(E) are diagrams illustrating the position calculation method. [Diagram 5] 13 is a flowchart of a method for measuring measurement points using the system. [Figure 6] 11A and 11B are diagrams illustrating another modified example of the position calculation method. [Figure 7] 13 is a flowchart of a measurement method according to the modified example. [Figure 8] FIG. 13 is a diagram showing an example of a screen displayed on a display unit of a GNSS positioning system according to another modified example. [Figure 9] FIG. 11 is a configuration block diagram of a GNSS positioning system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. In addition, in each embodiment, the same components are given the same reference numerals, and duplicated descriptions are omitted.

[0019] I. First embodiment 1. Overall structure Fig. 1(A) is a diagram showing a schematic configuration of a GNSS positioning system (hereinafter simply referred to as a system) 1 according to a first embodiment of the present invention. Fig. 1(B) is a plan view showing a schematic arrangement of antennas inside a receiver 2 constituting the system 1. Fig. 2 is a block diagram of the GNSS positioning system. The system 1 according to the illustrated example is a GNSS positioning system used for RTK surveying.

[0020] The system 1 generally includes a receiver 2, a data processing device 3, and a pole 4. In the illustrated example, the receiver 2 and the data processing device 3 are configured separately and are connected to each other so as to be able to communicate with each other wirelessly or via a wire.

[0021] The pole 4 is a rod-shaped member having a predetermined length Ah and has a disk 4a at its upper end. The length Ah of the pole is known. The pole 4 is suspended from the disk 4a so that its central axis passes through the center of the disk 4a. The pole 4 is supported so that the center of the disk 4a is the center of the receiver 2, i.e., the center O of the antenna 20. The tip 4b of the lower end of the pole 4 is tapered. With the tip 4b in contact with the measurement point P and the pole 4 held vertically, the receiver 2 receives a ranging signal from a GNSS satellite to determine the position coordinate of the center O of the antenna 20, and the position coordinate of the measurement point P can be measured based on the length Ah of the pole and the position coordinate of the center O.

[0022] 2. Receiver The receiver 2 receives a ranging signal transmitted from a GNSS satellite and measures the position coordinates of its center O. The receiver 2 includes an antenna 20 and a receiver communication unit 25. The antenna 20 includes three small antennas (a first small antenna 21a, a second small antenna 21b, and a third small antenna 21c). Each of the three small antennas 21a, 21b, and 21c includes an antenna for receiving a ranging signal transmitted from a GNSS satellite and a receiver body for converting the received ranging signal into an electrical signal. The three small antennas 21a, 21b, and 21c are each connected to the receiver communication unit 25. Each of the small antennas 21a, 21b, and 21c receives ranging signals from at least four GNSS satellites.

[0023] 1(B), the three small antennas 21a, 21b, and 21c are arranged to form an equilateral triangle on a circumference centered on the position of the center O of the antenna 20. As a result, the center of gravity G of the equilateral triangle coincides with the center O of the antenna 20.

[0024] The receiver communication unit 25 is a communication interface that enables wired or wireless data exchange with the processing device communication unit 33 of the data processing device 3. The receiver communication unit 25 transmits the ranging signals received by the three small antennas 21a, 21b, and 21c and converted into electric signals to the communication unit of the data processing device 3.

[0025] 3. Data Processing Device The data processing device 3 is a so-called computer. The data processing device 3 includes a display unit 31, an input unit 32, a processing device communication unit 33, a storage unit 34, and a control and calculation unit 35.

[0026] The display unit 31 is, for example, a liquid crystal display, an organic EL display, or the like. The input unit is, for example, a keyboard, a mouse, a touch panel, or other input device. In the illustrated example, the display unit 31 and the input unit 32 are integrally configured as a touch panel display. The display unit 31 displays information to be provided to the user, such as the measurement results by the system 1, the measurement conditions, and other information related to the measurement. The input unit 32 enables the user to input instructions, conditions, information, and the like for the system 1 to the control and calculation unit 35.

[0027] The processing device communication unit 33 is a communication interface equivalent to the receiver communication unit 25. Under the control of the control and arithmetic unit 35, the processing device communication unit 33 enables wired or wireless transmission and reception of information between the data processing device 3 and the receiver 2.

[0028] The control calculation unit 35 includes at least one processing circuit. The processing circuit may be a processor such as a CPU (Central Processing Unit). When the processing circuit is a CPU, a program for executing each function of the control calculation unit 35 described below is read into a memory to realize each function in a software manner. For this purpose, the control calculation unit 35 may include at least one memory (storage medium) such as an SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory). In addition, the control calculation unit 35 may include, as a processing circuit, a PLD (Programmable Logic Device) such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array) that realizes part or all of the functions of the control calculation unit 35 in a hardware manner.

[0029] The control and calculation unit 35 calculates the position coordinates of the center O of the receiver 2 based on the distance measurement signal input from the receiver 2. A method for calculating the position coordinates of the center O of the receiver 2 will be described later. The control and calculation unit 35 displays on the display unit 31 information to be provided to the user, such as the measurement results by the system 1, the measurement conditions, and other information related to the measurement.

[0030] The storage unit 34 is a computer-readable storage medium such as a hard disk drive (HDD) or a flash memory. The storage unit 34 stores a program for executing the data processing device 3. The storage unit 34 also stores various data such as raw data, which is an electrical signal received from the receiver 2, and calculation results of position coordinates by the control and calculation unit 35.

[0031] 4.Position calculation method Fig. 3 is a flowchart of the position calculation method by the system 1. Fig. 4 is a diagram for explaining the position calculation method. The position calculation method is executed by the control and calculation unit 35 using the reception signal input from the receiver 2.

[0032] When calculation is started, first, in step S01, the control calculation unit 35 calculates the position coordinates of each small antenna 21a, 21b, 21c from the distance measurement signals acquired at the same time by each small antenna (first small antenna 21a, second small antenna 21b, third small antenna 21c). Here, the three actual small antennas 21a, 21b, 21c are arranged to form an equilateral triangle (hereinafter referred to as the arrangement triangle 22) having a center of gravity G2 with vertices 22a, 22b, 22c corresponding to the small antennas 21a, 21b, 21c, as shown in Fig. 4(A).

[0033] Next, in step S02, the control calculation unit 35 uses the calculated position coordinates of each small antenna 21a, 21b, 21c to obtain a calculated triangle 42, and calculates the center of gravity G4 of the calculated triangle 42. Fig. 4(B) is a diagram showing the calculated triangle 42, in which vertices 42a, 42b, 42c correspond to position coordinates calculated from the received signals of the first small antenna 21a, the second small antenna 21b, and the third small antenna 21c, respectively. Since the calculated values ​​of the position coordinates each contain an error, the calculated triangle 42 is not an equilateral triangle, as shown in Fig. 4(B).

[0034] Next, in step S03, the control calculation unit 35 superimposes the layout triangle 22 on the calculation triangle 42 so that the center of gravity G4 of the calculation triangle 42 coincides with the center of gravity G2 of the layout triangle 22, as shown in FIG. 4(C).

[0035] Next, in step S04, the control calculation unit 35 calculates the arrangement of the arrangement triangle 22 in which the deviation between each vertex 42a, 42b, 42c of the overlapped calculated triangle 42 and each vertex 22a, 22b, 22c of the arrangement triangle 22 is minimized. Specifically, as shown in FIG. 4(D), while adjusting the position of the arrangement triangle 22 with respect to each vertex 42a, 42b, 42c of the calculated triangle 42, the deviation between each vertex 42a, 42b, 42c and each vertex 22a, 22b, 22c is calculated each time. Then, when the deviation becomes minimum, the position adjustment is converged. This arrangement, illustrated in FIG. 4(E), is called the minimum deviation arrangement.

[0036] Next, in step S05, the control calculation unit 35 calculates the center of gravity G2 of the arrangement triangle 22 resulting in the minimum deviation arrangement as the center of gravity G of the three small antennas 21a, 21b, and 21c, i.e., the coordinates of the center O of the antenna 20 (the coordinates of the center O of the receiver 2), and terminates the processing.

[0037] The position coordinates of the center O of the receiver 2 obtained in this manner use the three small antennas 21a, 21b, and 21c, so the errors are averaged, and the error is reduced compared to when a distance measurement signal is received using one antenna. On the other hand, even if three antennas are used for the purpose of averaging the errors, it is actually impossible to arrange the antennas in the same place due to three-dimensional obstacles. Therefore, the small antennas are arranged to form an equilateral triangle with a wide area in a plane, and the center of gravity G4 is calculated as the center O of the receiver 2 to be measured, thereby making it possible to reduce the error by averaging the errors caused by the three small antennas 21a, 21b, and 21c. In addition, by arranging the small antennas 21a, 21b, and 21c in an equilateral triangle with a wide area in a plane within the same receiver 2, the influence of the radio wave reception state (reception accuracy) caused by the presence of obstacles nearby is also different for each. Therefore, the influence on the measurement value is averaged and reduced compared to when only one antenna is used. Therefore, it is possible to calculate position coordinates with higher accuracy than before.

[0038] This is particularly advantageous when, for example, there is an obstacle nearby and some of the small antennas cause large errors, as the effect of this can be reduced compared to using one antenna.

[0039] In the calculation of the arrangement with the minimum deviation in step S04, the convergence of the position adjustment may be determined by calculating the variation (e.g., RMS (Root Mean Square)) using data acquired continuously for a predetermined time or acquired multiple times at predetermined intervals in the calculation of the position coordinates of each small antenna, and weighting according to the variation. Specifically, for example, the convergence may be determined by giving priority to the arrangement with the smallest deviation for the vertex corresponding to the small antenna with the smallest variation.

[0040] In this way, the accuracy of the arrangement with the minimum deviation is improved, and the position coordinates can be calculated with higher accuracy.

[0041] 5. Surveying method using System 1 We will now explain how to use the system 1. The system 1 determines the position coordinates of the measurement point P by abutting the tip 4b of the pole 4 of the receiver 2 against the measurement point and receiving a signal from a GNSS satellite while holding the pole 4 vertically. A spirit level may be provided on the pole 4 to hold the pole 4 vertically.

[0042] 5 is a flowchart of a surveying method using the system 1. When measurement is started, in step S11, the tip 4b of the pole 4 is brought into contact with the measurement point, and while the pole 4 is held vertically, the small antennas 21a, 21b, and 21c of the receiver 2 receive ranging signals from at least four GNSS satellites.

[0043] In step S12, the receiver 2 outputs the received distance measurement signal to the data processing device 3 (the control and calculation unit 35 thereof).

[0044] Next, in step S13, the control and calculation unit 35 of the data processing device 3 measures the position coordinates of the center O of the receiver 2 through steps S01 to S05.

[0045] Next, in step S14, the control and calculation unit 35 calculates the position coordinates of the measurement point P based on the position coordinates of the center O of the receiver 2 calculated in step S13 and the known length Ah of the pole 4, and then ends the process.

[0046] 6. Variation 1 The system 1 according to this embodiment can be modified as follows. 6(A) and (B) are diagrams for explaining the positional relationship between the pole in the system 1 and the plane α on which the three small antennas 21a, 21b, and 21c are placed.

[0047] As shown in Fig. 6(A), the three small antennas 21a, 21b, and 21c are arranged on a plane α perpendicular to the pole 4. By determining the position coordinates of the three small antennas 21a, 21b, and 21c, it is possible to determine the plane α on which the three small antennas 21a, 21b, and 21c are placed. As a result, it is also possible to determine the inclination β of the plane α (i.e., the pole 4).

[0048] FIG. 7 is a flowchart of a measurement method using the system of the first modified example.

[0049] When measurement starts, in steps S21 to S23, similar to steps S11 to S13, distance measurement signals are received by each of the small antennas 21a, 21b, and 21c, and the coordinates of the center O of the receiver 2 are calculated similar to steps S01 to S05.

[0050] Next, in step S24, the control calculation unit 35 calculates the plane α, and calculates the inclination β of the pole 4.

[0051] Next, in step S25, the control and calculation unit 35 calculates the coordinates of the measurement point P taking into account the inclination β, and then ends the process.

[0052] For example, as disclosed in Patent Document 1, in a conventional GNSS positioning system, an inclination sensor is provided to correct errors caused by the inclination of the pole. In this embodiment, since three small antennas are provided, it is possible to calculate the measurement point coordinates taking into account the inclination of the pole 4 without providing an inclination sensor.

[0053] 7. Variation 2 In addition, the following modification may be applied using the inclination β of the small antenna mounting plane α calculated in the first modification.

[0054] FIG. 8 is a diagram showing a display screen 50 displayed on the display unit 31 of the data processing device 3 according to the second modification.

[0055] In the data processing device 3 according to the present modified example 2, in addition to measurement data 51 such as the measurement values ​​of the measurement points, the tilt β of the pole 4 is displayed as a round bubble tube 52 on the display screen 50 of the display unit 31. A bubble 53 indicating the tilt β of the pole 4 is displayed in the bubble tube 52. In addition, the display screen 50 may also display an indication 54 indicating the reception state of the GNSS signal, an indication 45 indicating the measurement time, and the like.

[0056] While checking the position of bubble 53, the operator can adjust the inclination of pole 4 so that bubble 53 is in the center of bubble tube 52, thereby holding pole 4 vertically. In this way, even without providing an inclination sensor, the verticality of pole 4 can be ensured, enabling measurements with reduced error.

[0057] II. Second embodiment 9 is a configuration block diagram of a GNSS positioning system 100 according to the second embodiment. In the system 100, the receiver 102 has an antenna 20 having the same configuration as that of the system 1, but includes a receiver storage unit 27 and an I / O unit 28 instead of or in addition to the communication unit 26. The data processing device 103 includes an I / O unit 36 ​​instead of or in addition to the processing device communication unit 33.

[0058] The receiver storage unit 27 is a computer-readable storage medium such as a hard disk drive (HDD) or a flash memory. The receiver storage unit 27 stores data, which is obtained by converting the distance measurement signals measured by the small antennas 21a, 21b, and 21c into electrical signals, each time the data is acquired. The I / O units 28 and 36 are equivalent USB ports or the like, and enable input and output of data by connecting with a USB cable. Alternatively, the I / O units 28 and 36 may be communication means using short-range wireless communication such as Bluetooth (registered trademark).

[0059] With the above configuration, in system 100, measurements are taken for a predetermined period at the location where receiver 102 is installed, and the measurement data is stored in receiver storage unit 27. After the measurement for the predetermined period, the user takes the receiver 102 back to an office or the like, connects receiver 102 to data processing device 103 via I / O units 28 and 36, and inputs the measurement data into data processing device 103 for processing in data processing device 103. In data processing device 103, the same processing as in data processing device 3 is carried out.

[0060] In this way, system 100 may be configured as a GNSS positioning system that performs static observations that perform long-term measurements at the location where receiver 102 is installed, rather than a GNSS positioning system that performs RTK observations that process ranging signals in real time and calculate position coordinates like system 1.

[0061] The above describes preferred embodiments of the present invention. However, the above embodiments are merely examples of the present invention, and these can be combined based on the knowledge of those skilled in the art, and such combinations are also included in the scope of the present invention. [Explanation of symbols]

[0062] 1,100:GNSS positioning system 2,102: Receiver 3,103: Data processing device (computer) 4: Paul 4b: Tip 20: Antenna 21a: First small antenna 21b: Second small antenna 21c: Third small antenna 22: Placement triangle 22a, 22b, 22c: Vertices (of a triangle) 31: Display section 35: Control calculation section 42: Mathematical triangle 42a, 42b, 42c: Vertices (of a mathematical triangle) G2: Center of gravity (of the arrangement triangle) G4: Center of gravity (of a mathematical triangle) O: Center α :plane β: Slope

Claims

1. An antenna for receiving ranging signals from GNSS satellites; a control and calculation unit for calculating a position of the center of the antenna based on the distance measurement signal; A GNSS positioning system comprising: The antenna comprises three small antennas; the three small antennas are arranged to form an equilateral triangle on a circumference centered on the center position of the antenna, The control and calculation unit calculates the positions of the three small antennas from the ranging signals received by each of the three small antennas, and calculates the center of gravity of a calculated triangle having the calculated positions of the three small antennas as vertices as the center position of the antenna. A GNSS positioning system comprising:

2. A pole supporting the antenna is further provided. The pole is provided such that a distance from a tip of the pole to a center of the antenna is known, and a central axis of the pole passes through a center of the antenna, The GNSS positioning system according to claim 1 , wherein the control and calculation unit calculates coordinates of a measurement point that abuts against the tip that is held vertically.

3. The control calculation unit is superimposing the arrangement triangle on the calculated triangle such that the center of gravity of the calculated triangle coincides with the center of gravity of the arrangement triangle, which is an equilateral triangle formed by the three small antennas; adjusting the positions of the two triangles from a state where the arrangement triangle and the calculated triangle are superimposed on each other to obtain a minimum deviation arrangement in which the deviation of the corresponding vertices is minimized; 3. The GNSS positioning system according to claim 1, wherein the center of gravity of the arrangement triangle that results in the minimum deviation arrangement is calculated as the position of the center of the antenna.

4. 4. The GNSS positioning system according to claim 3, wherein the control and calculation unit performs weighting in the calculation of the minimum deviation arrangement according to a variation in the calculated position of each small antenna.

5. The GNSS positioning system described in claim 2, characterized in that the control and calculation unit calculates the plane in which the small antenna is located based on the calculated position of each small antenna, thereby calculating the inclination of the pole, and calculating the coordinates of the measurement point taking into account the inclination.

6. Further, a display unit is provided, The GNSS positioning system according to claim 2, characterized in that the control and calculation unit calculates a plane on which the small antenna is located based on the calculated positions of each small antenna, calculates the inclination of the plane, and displays the inclination on the display unit.

7. A step of receiving the ranging signal from the GNSS satellite with each small antenna by using a receiver having an antenna, the receiver having three small antennas arranged to form an equilateral triangle on a circumference centered on the center of the antenna, and converting the ranging signal into an electrical signal; A computer calculates the location of each small antenna from the ranging signal received by each small antenna; and a step of the computer calculating the position of the center of gravity of the three small antennas as the position of the center of the antenna. A GNSS positioning method comprising:

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