JP2022053432A - Low cost RTK-GNSS - Google Patents

Abstract

To provide a low cost RTK-GNSS that, by constructing a dedicated NTRIP Caster for exchanging information between two points, a base station and a mobile station, realizes transmission and reception of observation data and correction data of a GNSS via the Internet and enables inexpensive and continuously stable operation.SOLUTION: An NTRIP system of the present invention is divided into a TCP Server and a TCP Client, the TCP Server is a dedicated TRIP Caster, and the TCP Client is an NTRIP Server (base station) and an NTRIP Client (rover station). Data received by the NTRIP Server (base station) is transmitted to an NTRIP Caster which is the TCP Server via the Internet, whereas the NTRIP Client (rover station) is connected to the NTRIP Caster, and the data is received and analyzed. Dedicated NTRIP Caster software installs and operates a virtual dedicated server (VPS).SELECTED DRAWING: Figure 1

Description

Detailed description of the invention

By constructing a dedicated NTRIP Castor that exchanges information between two points between the base station and the mobile station, transmission and reception of GNSS observation data and correction data can be realized via the Internet, and it is inexpensive and continuously stable. We provide low-cost RTK-GNSS to be operated.

Background of the invention

[Overview of low-cost RTK-GNSS]
RTK-GNSS surveying is a technology that has already been put into practical use. In particular, network-type RTK-GNSS surveying has been available since April 2013 for GPS (US), Quasi-Zenith Satellite (Japan) and GLONASS (Russia). Since the data became available, it is used and widely used in the 3rd and 4th grade reference point surveys of public surveying. However, the high cost of GNSS receivers and the high running costs have been confronted as barriers that are difficult for small and medium-sized enterprises to introduce. On the other hand, in recent years, inexpensive and high-performance GNSS receivers have become commercially available, and research on their use for autonomous driving and surveying is rapidly progressing.

[Principle of GNSS]
As shown in FIG. 26, the mechanism of GNSS is calculated from the distances from the three satellites and the position of the surface of the earth. The (signal code) radio wave transmitted from the GNSS satellite reaches the ground at a speed of light of 299,792.458 rn / s (about 300,000 kilometers per second). By measuring the time of transmission and the time of arrival, the distance from the satellite is measured as follows. This is called rangeing. Radio wave arrival time (receiver from GNSS satellite) x radio wave speed (speed of light) = distance from GNSS satellite Once the distance from the GNSS satellite is known, it is somewhere on a spherical surface whose radius is the distance centered on that satellite. It will be. Since the position (orbit) of a satellite is transmitted from GNSS and known, by knowing the distances from multiple satellites, the intersection of the spherical surfaces is the current location. In other words, the principle of triangulation requires at least three satellites. It is also called a code positioning method because it uses a signal code. An atomic clock is required to accurately measure the arrival time of the signal code of the speed of light. Two or more atomic clocks are mounted on the GNSS satellite, but it is difficult to mount them on the GNSS receiving side in terms of cost and size. Therefore, a crystal oscillator clock is used on the receiver side, but due to poor accuracy, measurement is performed while correcting for the time that arrives from the satellite. In other words, at least four satellites are required to correct the time. The arrangement status of GNSS satellites is represented by a numerical value called DOP (Diltion of Precision: accuracy reduction rate). When the number of satellites received is small and the GNSS satellite positions are not far apart, the error becomes large because the crossing angle becomes small according to the principle of triangulation. If the satellites are not placed properly in the sky, the accuracy will deteriorate. There are the following types of DOP. (1) GDOP: Geometric accuracy decrease rate, (2) PDOP: Position accuracy decrease rate, (3) HDOP: Horizontal accuracy decrease rate, (4) VDOP: Vertical accuracy decrease rate, (5) TDOP: Time accuracy decrease rate , (6) RDOP: Relative accuracy reduction rate.

[GNSS surveying method]
As shown in FIG. 27, there are several types of GNSS surveying methods depending on the accuracy and positioning method. Among these, RTK-GNSS (real-time kinematics) is usually used in information-oriented construction (i-Construction).

Independent positioning; As shown in FIG. 28, by receiving information such as the position and time of the satellite transmitted from the GNSS satellite with one antenna, it is necessary from the time when the radio wave is transmitted from the satellite to the time when it reaches the receiver. Measure the time and convert it to a distance. The position of the observation point is determined by simultaneously knowing the distances from four or more satellites to the observation point, using the GNSS satellite whose position is known as a moving reference point. In this method, the position is determined with an error of about 10 m due to the position error of the satellite and the delay of the radio wave when the radio wave from the satellite passes through the troposphere and the ionosphere. It is used as a navigation system for ships, airplanes, and automobiles. By receiving information such as the position and time of the satellite transmitted from the GNSS satellite with one antenna, the time required from the transmission of radio waves from the satellite to the arrival at the receiver is measured and converted into distance. .. The position of the observation point is determined by simultaneously knowing the distances from four or more satellites to the observation point, using the GNSS satellite whose position is known as the moving reference point. This method cannot be used for surveying because the position is determined with an error of about 10 m due to the position error of the satellite and the delay of the radio wave when the radio wave from the satellite passes through the troposphere and the ionosphere. It is used as a navigation system for airplanes and automobiles.

Relative positioning; As shown in FIG. 29, two or more receivers are used to observe four or more same GNSS satellites at the same time. Relative positioning is a method of measuring the time difference between the radio signals from the GNSS satellites reaching each receiver based on the position of the GNSS satellites and obtaining the relative positional relationship between the two points. Since the radio waves of the same satellite are received at each observation point and the radio waves emitted from the satellite pass through the same weather conditions, observation is performed by taking the difference between the observation values of the two points. The satellite position error and troposphere / ionospheric delay included in the value are eliminated. High-resolution radio waves are used for surveying. By knowing the difference in the time it takes for the radio waves emitted from the satellite to reach each antenna by the phase difference, the relative positional relationship between the two points can be determined with an accuracy of 1 in 1,000,000 (1 cm error at 10 km). I understand.

DGNSS positioning; As shown in FIG. 30, in DGNSS (differential GNSS) positioning, GNSS observation is performed simultaneously at a reference station whose position is known and an observation point for which a position is to be obtained, and the data observed at the reference station is observed by radio or the like. It can be transmitted to the point in real time, and the position of the observation point can be obtained in real time based on the position result of the reference station. DGNSS performs independent positioning at both points, obtains the difference between the position result and the observed coordinate value at the reference station, and sends it to the observation point as correction information. Since various error factors are eliminated by this observation method, the position is determined with an error of several meters.

Interference positioning; In interference positioning, as shown in FIG. 31, GNSS antennas are installed at known points and unknown points, the baseline vectors of both points are measured using the deviation of satellite radio wave arrival, and the coordinate data of the unknown points are obtained. This is the method to be sought. The observation methods are classified into static method, shortened static method, kinematic method, RTK method and the like.

RTK-GNSS positioning; RTK-GNSS positioning, as shown in FIG. 32, has an error of several meters in GNSS generally used in smart phone and car navigation. This is because the distance to the GNSS satellite is long, and various physical phenomena that occur in outer space and the atmosphere cause fluctuations in the arrival time of radio waves. In addition, radio waves are blocked in urban areas, and factors such as multipath reflecting on buildings also cause deterioration in accuracy. In RTK-GNSS (real-time kinematic GNSS) positioning, the phase is measured at both points and the phase data observed at the reference station is transmitted to the observation point. The GNSS receiver at the observation point determines the position of the observation point by analyzing the received data and the data transmitted from the reference station in real time. Since various error factors are eliminated by this method as well, the position is determined with an error of several centimeters. If RTK-GNSS technology is used, it is expected to have various applications such as high-precision surveying in civil engineering work by mounting it on a drone or tractor. Recently, Japan's quasi-zenith satellite system QZSS (Quasi-Zenith Satellite System) Michibiki has been successfully launched, and since November 2018, it has become a four-machine system. In the new "Space Basic Plan" formulated in January 2015, it is decided that "operation will start with a system of seven aircraft capable of continuous positioning by 2023." Unlike satellites such as the United States (GPS), China (BeiDou), and Russia (GLONASS), QZSS alternates and is always located at the zenith of Japan. If the altitude is low, you will receive the signal from the diagonal side, but if you are located at the zenith, you can receive the signal directly even in the urban area surrounded by buildings, so you can reduce the deterioration of accuracy. .. RTK-GNSS has 1/100 accuracy compared to conventional single positioning. That is, it is possible to obtain the distance between the reference station and the mobile station with an accuracy of 1 cm or less. In principle, the minimum resolution is 0.744 mm, which corresponds to 1/256 of the wavelength of 19.0425 cm of the carrier wave transmitted by the satellite. However, even in the case of RTK-GNSS positioning, there is a fluctuation factor, so an error of about 1 cm is obtained. This is the same even if the reference station and the mobile station are separated by about 10 km. As a matter of course, RTK-GNSS technology requires a reference station whose coordinates are known in mm in addition to the satellite signal. The RTK-GNSS technology is not so new, and has been used for civil engineering surveys and non-agricultural machinery for a long time, and is the latest technology that is expected to improve convenience in the future. However, the system so far has been a large-scale system that costs several million yen. The system used in the RTK study group is an inexpensive module called ZED-F9P released by u-blox, which enables high-precision surveying.

Network-type RTK-GNSS positioning; As shown in FIG. 33, network-type RTK-GNSS surveying is not good at RTK-GNSS by correcting errors included in observations using real-time observation data of electronic reference points. It enables surveying of long-distance baselines and has the same positioning accuracy as RTK-GNSS of short-distance baselines. Several methods have been proposed for network-type RTK-GNSS surveying, which have already been put into practical use in several countries including Japan, but the disadvantages are that the equipment itself is expensive and running costs are high. ..

[Principle of RTK-GNSS and observation method]
The main components of RTK-GNSS are a base station, a data transmission system, and a mobile station installed at known points. FIG. 34 is a principle diagram of RTK-GNSS, but the receiver of the reference station installed at a known fixed point always receives radio waves from a visible satellite and measures the integrated value data of the carrier phase. Then, the positioning data including those data is transmitted to the mobile station via the Internet or a wireless device. Similarly, the carrier phase of a mobile station is measured and used together with the positioning data transmitted from the reference station to obtain the three-dimensional position of the mobile station in real time. It is said that if the distance from the reference station is within 10 km, the position of the mobile station can be obtained with an accuracy of 1 cm. On the other hand, the number of positioning satellites is increasing year by year, and it is expected that measurement can be performed even in areas with limited aerial visibility such as building streets and mountainous areas. The observation method is to connect a personal computer to the antenna and receiver for analysis. The time required for analysis is 10 seconds after Fix, and observation analysis is performed while moving the observation point.

Conventional example

Patent Document 1 (Japanese Patent Laid-Open No. 2019-203812) states that "in a positioning system, precision position data is acquired using positioning information collected from a plurality of base stations, and the acquired precision position data is distributed to the base station. In the positioning system, the base station that is the position reference station can always hold the precise position data based on the result data of the precision measurement. In the positioning system, the base station whose precise position is known can be used as the position reference station. For example, since RTK positioning is performed with the mobile station, the position of the mobile station can be measured with high accuracy. Further, in the positioning system, in addition to the communication handover, for example, with the position reference station for RTK positioning. Since the base station can be switched, it is possible to always perform high-precision positioning even when the mobile station moves at high speed. " In addition, we will realize a positioning technology that can measure the position with high reliability, high accuracy, and high speed. "

However, in this Patent Document 1, "... the data received at the base station is transmitted to a TCP Server called NTRIP Caster via the Internet with an IP address or the like, and the same is true on the mobile station side. It connects to the NTRIP Castor with an IP address, etc., receives and analyzes the data, installs and operates the NTRIP Caster software on the VPS (virtual dedicated server), and is a base near the mobile station for positioning. Both stations receive common satellite radio waves, and the fixed base station consists of an antenna, receiver, personal computer, and wireless LAN router (Wi-FI router), and the receiver is GPS / QZSS (L1, L2). ), GLONASS (G 1.G2), Galileo (E1, E5b) The ZED-F9P module, which is a dual-frequency multi-GNSS receiving chip corresponding to the signals of BeiDou (BI, B21), was installed and arrived at the transmitted time. By measuring the time, the position of the observation point is determined by the principle of triangulation to determine the distance from a plurality of satellites ... "The point is not described at all, and the present invention is described from this Patent Document 1. I can't easily recall.

Patent Document 2 (Japanese Unexamined Patent Publication No. 2018-169285) states that "the reference station base 20 includes a base member 21, a storage unit 22, and a transmission unit 23. The base member 21 is fixedly provided with respect to the earth. The storage unit 22 stores the position coordinates indicating the installation location of the base member 21. The transmission unit 23 stores the storage unit when the portable GNSS reference station device 30 is attached to the base member 21. It is described that the position coordinates stored in 22 can be transmitted to the GNSS reference station device 30, thereby reducing the installation cost of the reference station and reducing the labor and burden on the user during installation. ..

However, in this Patent Document 2, "... the data received at the base station is transmitted to a TCP Server called NTRIP Caster via the Internet with an IP address or the like, and the same is true on the mobile station side. It connects to the NTRIP Castor with an IP address, etc., receives and analyzes the data, installs and operates the NTRIP Caster software on the VPS (virtual dedicated server), and is a base near the mobile station for positioning. Both stations receive common satellite radio waves, and the fixed base station consists of an antenna, receiver, personal computer, and wireless LAN router (Wi-FI router), and the receiver is GPS / QZSS (L1, L2). ), GLONASS (G 1.G2), Galileo (E1, E5b) The ZED-F9P module, which is a dual-frequency multi-GNSS receiving chip corresponding to the signals of BeiDou (BI, B21), was installed and arrived at the transmitted time. By measuring the time, the position of the observation point is determined by the principle of triangulation to determine the distance from a plurality of satellites ... "The point is not described at all, and the present invention is described from this Patent Document 2. I can't easily recall.

Patent Document 3. In (Actual No. 3197633), "A measuring device 1 is provided at an upper position of an amphibious construction machine via an impact shock absorber, and the measuring device is equipped with a wireless positioning system mobile station 13, and is an amphibious construction machine. Data calculation processing that receives and performs calculation processing of position data transmitted from the wireless positioning system reference station 2 as a reference for acquiring the position data of the measuring device at different positions, and the wireless positioning system mobile station and the wireless positioning system reference station. It is equipped with a device 3 and a construction status reference monitor 4 for displaying the result of its arithmetic processing. " While running, it is possible to obtain the position information of amphibious construction machines and accurate three-dimensional information of the ground in shallow water, and it is possible to automatically measure the finished shape of the ground after construction, and the finished work after construction in real time. We will provide a construction support system for amphibious construction machines that can inform the operator of the condition of the ground at the time of construction with respect to the design value of the shape. "

However, in this Patent Document 3, the "Base Station" and the Mobile Station (Rover Station) of the present invention have two receivers, and GNSS observation data for exchanging information between these two points in real time. It is an NTRIP that realizes transmission and reception of correction data via the Internet, and the data received at the base station is sent to the TCP Server called NTRIP Castor via the Internet with an IP address, etc., and the same IP is used on the mobile station side. It connects to the NTRIP Castor with an address, etc., receives and analyzes the data, installs and operates the NTRIP Castor software on the VPS (virtual dedicated server), and is a base station located at a short distance from the mobile station for positioning. The fixed base station consists of an antenna, a receiver, a personal computer, and a wireless LAN router (Wi-FI router), and the receiver is GPS / QZSS (L1, L2). , GLONASS (G 1.G2), Galileo (E1, E5b) Equipped with ZED-F9P module, which is a dual frequency multi-GNSS receiving chip corresponding to BeiDou (BI, B21) signals, transmitted time and arrival time There is no description about "low-cost RTK-GNSS" in which the position of the observation point is determined by the principle of triangular measurement based on the distance from a plurality of satellites by measuring the data, and the present invention can be easily described from Patent Document 3. I can't recall.

US Pat. The separation distance in the direction is obtained. By this, it is determined whether the positioning point is in the position of the out-of-track area or the in-track area of the railway track area, and whether the in-track position is a caution zone or a dangerous zone. , Gives accurate information about the position and safety of each worker in the railway track area. " Accurately classify and grasp areas such as (outside the track), caution areas (outside the construction limit inside the track), dangerous areas (within the construction limit inside the track), etc., and provide appropriate warnings and displays according to the classification. " It is explained.

However, in this Patent Document 4, "... NTRIP, which is NTRIP, and the data received at the base station is transmitted to a TCP Server called NTRIP Castor via the Internet with an IP address or the like, and is a mobile station. On the side, it connects to the NTRIP Castor with the same IP address, etc., receives and analyzes the data, and installs and operates the NTRIP Caster software on the VPS (virtual dedicated server), and is close to the mobile station for positioning. Both base stations at a distance receive common satellite radio waves, and the fixed base station consists of an antenna, a receiver, a personal computer, and a wireless LAN router (Wi-FI router), and the receiver is GPS / QZSS (Wi-FI router). The ZED-F9P module, which is a dual-frequency multi-GNSS receiving chip corresponding to the signals of L1., L2), GLONASS (G1.G2), Galileo (E1, E5b) BeiDou (BI, B21), is installed and transmitted. There is no description about "Low-cost RTK-GNSS" that determines the position of the observation point based on the principle of triangular measurement based on the distance from multiple satellites by measuring the time of arrival. The present invention cannot be easily recalled.

In Patent Document 5 (Japanese Patent Laid-Open No. 10-082848), "a reference station 1 for transmitting pseudo-distance correction information and carrier phase phase correction information calculated based on received satellite signals to each mobile station 2 and a precise position are known. It has a calibration facility 3 having a certain calibration point and scattered in large numbers, and the mobile station 2 has a DGNSS positioning function of a normal pseudo-distance correction method and a cycle ambiguity removal by a normal initial baseline analysis. It is composed of a mobile station 2 having an unnecessary RTK positioning function, and when the mobile station 2 automatically detects a calibration point approached within a certain range by DGNSS positioning while moving, the built-in switch is used as the calibration point. By pressing and turning it on, cycle ambiguity is automatically removed based on the position information of the calibration point, and continuous RTK positioning is performed based on the carrier phase correction information sent from the reference station 1. " It is stated that this will "provide a satellite positioning system that can remove the cycle ambiguity generated during movement with an inexpensive and simple configuration".

However, in this Patent Document 5, "... the data received at the base station is transmitted to a TCP Server called NTRIP Caster via the Internet with an IP address or the like, and the same is true on the mobile station side. It connects to the NTRIP Castor with an IP address, etc., receives and analyzes the data, installs and operates the NTRIP Caster software on the VPS (virtual dedicated server), and is a base near the mobile station for positioning. Both stations receive common satellite radio waves, and the fixed base station consists of an antenna, receiver, personal computer, and wireless LAN router (Wi-FI router), and the receiver is GPS / QZSS (L1, L2). ), GLONASS (G1.G2), Galileo (E1, E5b) Equipped with ZED-F9P module, which is a dual frequency multi-GNSS receiving chip corresponding to BeiDou (BI, B21) signals, transmitted time and arrival time The low-cost RTK-GNSS in which the position of the observation point is determined by the principle of triangular measurement based on the distance from a plurality of satellites by measuring the data is not described at all, and the present invention can be easily described from Patent Document 5. I can't recall.

Prior literature

Japanese Unexamined Patent Publication No. 2019-203812 Japanese Unexamined Patent Publication No. 2018-169285 Jitsuto 3197633 Gazette Japanese Unexamined Patent Publication No. 2006-224737 Japanese Unexamined Patent Publication No. 10-082848

Problems to be solved by the invention

By constructing a dedicated NTRIPCaster that exchanges information between two points between the base station and the mobile station, it is possible to send and receive GNSS observation data and correction data via the Internet, and operate it inexpensively and continuously and stably. An object of the present invention is to provide a low-cost RTK-GNSS.

Means to solve problems

The invention of claim 1 has two receivers, a base station and a mobile station, and sends and receives GNSS observation data and correction data that exchange information between these two points in real time. Is an NTRIP that realizes via the Internet, and the data received at the base station is transmitted to the TCP Server called NTRIP Caster via the Internet, and at the mobile station side, it is connected to the NTRIP Castor to receive and analyze the data. Therefore, the NTRIP Castor software is installed and operated on the VPS (virtual dedicated server), and both the mobile station for positioning and the base station at a short distance receive common satellite radio waves, and the fixed base station The receiver is equipped with a multi-band GNSS module, which is a dual-frequency multi-GNSS receiving chip, and by measuring the transmitted time and the arrival time, the distance from multiple satellites can be determined by the principle of triangular measurement. It provides a low cost RTK-GNSS to be determined.

In the present invention, by constructing a dedicated NTRIP Castor that exchanges information between two points between a base station and a mobile station, transmission / reception of GNSS observation data and correction data can be realized via the Internet, and can be continued inexpensively. It is possible to provide a low-cost RTK-GNSS protocol that enables stable operation.

The invention of claim 2 uses the temporary coordinates of the second fixed base station obtained from the fixed base station, and the temporary coordinates are used as the coordinates of the second fixed base station, and a nearby public reference point is positioned by a mobile station. By using the public reference point as a mobile station from the second fixed base station (temporary coordinates) and verifying the deviation between the coordinates of the public reference point and the coordinates obtained from the second fixed base station, this deviation is fixed second. It provides a low-cost RTK-GNSS that determines the coordinates on the earth of the antenna center of a fixed base station so as to be consistent with a public reference point by correcting and positioning from the temporary coordinates of the base station.

In the present invention, by ensuring consistency between the public reference point and the reference point, it is possible to confirm the positioning observation result in real time and shorten the work process using a conventional surveying instrument or the like.

In the invention of claim 3, the fixed base station includes an antenna, a receiver, a personal computer, a wireless LAN (Wi-Fi router), etc., and the receiver is a dual-frequency multi-GNSS receiving chip, and a multi-band GNSS module is ZED-F9P. The low-cost RTK-GNSS according to claim 1 or 2 is provided in which a board on which a module is mounted is used.

In the present invention, the price of the receiver is reduced, the receiver can receive two frequencies of the L1 band and the L2 band, the position calculation is quick, and the error of the positioning position due to the reception condition is reduced.

4. The invention provides the low-cost RTK-GNSS according to claim 1 to 3, wherein the deviation between the coordinates of a plurality of public reference points and the coordinates obtained from the second fixed base station is verified. be.

In the present invention, by achieving consistency between the public reference point and the reference point, it is possible to confirm the positioning observation result in real time and shorten the work process using a conventional surveying instrument or the like.

Low-cost RTK-GNSS can be positioned if there is a receiver and a personal computer that can use the Internet as a mobile station, but the overall mechanism is quite complicated, and NTRIP is required to exchange correction information between the base station and the Internet. Is. Here, the construction of the NTRIP Caster, the setting method and the positioning of the base station and the mobile station will be described.

RTK-GNSS positioning uses two receivers, a base station and a mobile station, but in order to exchange information between the two points in real time, an external radio or NTRIP (Networked) TT ・ satellite of RTCM via Internet Protocol] is required to realize the transmission and reception of GNSS observation data and correction data via the Internet. NTRIP generally uses a paid or free data distribution service by NTRIP Castor. However, in this embodiment, a dedicated NTRIP Caster is constructed for continuous and stable operation (Fig. 1). In the NTRIP method, both the base station and the mobile station are called TCP Clients and are received by the base station. Data is sent to a TCP Server called NTRIP Castor via the Internet with an IP address, port number, Moon Point, ID, and password. Next, on the mobile station side, the IP address, port number, Unit Point, ID, The NTRIP Caster is connected to the NTRIP Castor with a password, and the data is received and analyzed. In the embodiment of the present application, the NTRIP Castor software is installed and operated on two VPS (virtual dedicated servers) (one is a spare).

In a base station, if the radio waves of a common satellite are received by both the mobile station to be positioned and the base station at a certain short distance, the fluctuation of the arrival time of the radio waves, which is an error factor of GNSS single positioning, can be eliminated, so that the accuracy is high. Good positioning is possible. However, the accuracy of 1 cm can be achieved when the position of the mobile station is within a radius of 10 km from the base station whose latitude and longitude are accurately known, and the positioning accuracy is higher when using the base station as close as possible. Become. Assuming that the distance between the base station and the mobile station is D km, the accuracy is 1 cm + 2 ppm × D, and the accuracy decreases and the Fix rate also deteriorates as the distance from the base station increases. The equipment configuration of a fixed base station consists of an antenna, a receiver, a personal computer, and a wireless LAN router (Wi-Fi router). The receiver uses a board equipped with a ZED-F9P module manufactured by u-blox as a multi-band GNSS module. As for the personal computer, if the open source software RTK-GNSS library group RTKLIB can be executed, the minimum specifications are sufficient, but since the Windows machine is frequently updated, the learning computer in this embodiment is used. The popular Raspberry Pi (Raspberry P1) and software use RTKLIB str2str. The ZED-F9P is a dual-frequency multi-GNSS receiving chip corresponding to GPS / QZSS (L1., L2), GLONASS (G1.G2), Galileo (E1, E5b) BeiDou (BI, B21) signals.

The coordinate determination method for fixed base stations will be described below. In RTK-GNSS positioning, it is necessary to determine the coordinates of the antenna center of the fixed base station on the earth in order to obtain the relative positional relationship between the base station and the mobile station. The position error of the base station appears as the position error of the mobile station. Therefore, it is important that the position data of the base station is accurate, and it is generally obtained by the following method.
(1) A method of obtaining by RTK-GNSS with reference to other base stations.
(2) A method by PPK (Post Processing Kinematic) survey using an electronic reference point.
(3) A method of acquiring positioning data in a state of positioning for several days in the PPP Static (Precise Point Positioning Static) mode.
(4) Surveying by TS or VRS (Visual Reference Station: network type RTK-GNSS service).

Each has its own advantages and disadvantages, and considering the crustal movements that move from several mm to several cm per year, it is actually difficult to determine the position of the base station with an accuracy of 1 cm.
The method (1) is the simplest, but if the base station is not within 10 km, the accuracy will be poor.
The method (2) is reliable and highly accurate, but it requires observation for 24 hours or more, and the post-processing is complicated and troublesome.
The method (3) takes time, and finally, positioning can be performed only with an accuracy of several tens of centimeters or less.
The method (4) is certain, but it requires a certain amount of cost.

In this embodiment, the following methods have been examined and verified as methods for solving the problems of the above methods (1) to (4). Although it is a unique surveying method, it was confirmed that it is consistent with the local coordinates surveyed by TS.
(1) Find the location of the fixed base station (Daiichi Institute of Technology Aira Bureau) by the method (2) above.
Using the coordinate values of the fixed base station obtained in (2) and (1) as temporary coordinates, the coordinates of the nearby reference points are positioned by the mobile station.
The coordinate difference between the coordinates measured in (3) and (2) is corrected to the temporary coordinates of the I fixed base station in (1), and the coordinates of the first fixed base station are determined.

The coordinates of the reference point (class 2 reference point) near the first fixed base station are different from the base station obtained by GNSS due to the survey error of the reference point itself, the difference in the survey method, or the crustal movement. Since construction work is carried out based on national reference points and public reference points, it is necessary to match the coordinates of the reference points as much as possible.
(4) For the second fixed base station and below, obtain the temporary coordinates from the fixed base station (fixed base station as close as possible) obtained before that, and follow the procedure of (2) ▼ (3) to the nearby national reference point. Or, observe from the public reference point and correct and confirm the temporary coordinates.

The antenna of the fixed base station must be installed in a place where the sky view is open and there is no radio interference. A reception test was conducted based on the Aira base station of the first fixed base station at the antenna installation location of the Isa station, which is the second fixed base station. After that, the antenna wire was pulled into the room and the base station was set. Observe on the national reference point or public reference point near the base station, and correct the coordinate deviation to the temporary coordinates of the fixed base station and confirm. Tables 1 and 2 show the decision data of the I fixed station (Aira station) and the 2nd fixed station (Isa station). FIG. 2 is a flow chart of the above (1) to (4). FIG. 3 is a map showing a fixed base station installed by the coordinate determination method of the fixed base station. In addition, Daiichi Institute of Technology has a fixed base station monitoring monitor.

Next, the initial setting method of the receiver ZED-F9P is shown below.
(1) Connect the antenna and receiver to the PC and start u-center.
(2) Initialize with Configuration View.
(3) Connect to COM and open Messages View.
(4) Set Bad-Rate.
(5) Set the BeiDou B2 band decoder (not necessary if BeiDou is not used)
(6) View → Generation Connection View setting.
(7) View → Massages view → UBX → CFG → MSG
(8) Precision survey setting NMEA
(9) PRT setting

Next, regarding the installation of the field base station, unlike the fixed base station, the field base station is installed at a known point where the coordinates are known, but the equipment configuration is an antenna pole with a spirit level, a tripod for fixing the pole, and a tablet. A personal computer, a smart phone capable of Wi-FI tethering, or a mobile router is required. As with fixed base stations, the minimum specifications are sufficient for tablet PCs. A raspberry pie can be used instead of a tablet computer, but a Windows-equipped tablet is easy to use because of its portability and operability in the field. The software uses RTKLIB's strsvr.

For the setting of the field base station, the setting method in RTKLIB (strsvr) is described below for reproducibility.
(1) Start strrsvr (update etc. in advance).
(2) (0) Set Input Type to Serial and click Opti (Port is the port of the current PC).
(3) 2) Set the Output Type to NTRI Server and click Opti.

Regarding the setting of raspberry pie, Raspberry Pi has low power consumption and there is almost no update like Windows PC. RTK-GNSS is suitable for use as a fixed base station or a field base station. There are more than 10 types of Os based on the Linux system, and the general one is Raspbian. The types of Raspberry Pi are Raspberry Pi 3, Raspberry Pi 4. Many models are on sale, including the Raspberry P1 Zero. The keyboard and mouse are connected via USB or Bluetooth for use. In addition, the LAN port and WiFi are used to connect to the Internet. Here, the setting of the Raspberry Pi 3 will be described, but the Raspberry Pi 4 is basically the same as the Raspberry Pi 3. The personal computer used for installation is a Windows 10 personal computer.

Raspberry Pi basic settings and RTKLIB settings (1) Download OS image file;
Download URL; https: // www, raspberrypi. org / downloads / raspbian /
(2) When decompressed, a file with the extension img is created.
(3) Win32DiskImager is used to write Os to the SD card.
(4) -Search for "Win32 Disk Imager-1.0.0-instatl.exe" to download and install the win32 Disk Imager.
-Insert the SD card formatted with FAT32 into the personal computer and write the OS image.
(5) Insert the SD card into the Raspberry Pi and start it; install the OS according to the installation procedure of the Raspberry Pi.
(6) Install the text editor leafpad (7) Install RTKLIB (8) Create a shell script for executing a fixed base station

Next, wake up the sleep mode.
(1) Modification of LXDE-autostart (2) lightdm. Modification of conf (3) Restart Raspberry Pi

There are several types of auto-start methods using Raspberry Pi, but here we will explain the auto-start method using Systemd.
(1) Creation of script file; From the command line, start script file str2str. Create sh.
(2) Creation of Unit file (service setting).
(3) Service confirmation and registration.
Start the created "a. Service" and check the operation.

Next, the equipment configuration of the mobile station is almost the same as that of the base station, but the antenna (same type as the base station), receiver (same as the base station), two legs, RTK-GNSS pole, tablet, Wi-FI tethering. It consists of a possible smart phone or mobile router.

Explaining the method of setting the mobile station (RTKLIB), the elevation mask of the satellite and the SNR (Signal to Noise Ratio) indicating the signal strength from the satellite were adjusted by changing the combination, but in the end, 25 degrees, respectively. It is set to 30 dB. It depends on the satellite condition at the time of measurement, the weather, and the environment of the site, so tune according to the situation.
(1) Start rtknavi.
(2) Click "I" on the upper right to check Rover and Base Station.
(3) (I) Click "Opt" of Rover, and Port is COM at the time of setting.
(4) (2) Click "OPT" of Base Station to match NTRIP Caser Host 153.127.15.161 Port; 443 Password; User ID Mountpoint base station.
(5) Click "0" on the upper right to save the positioning data.
(6) Click the Option ... button at the bottom of the rtknavi top screen.
(7) Setting of SNR Mask.
(8) Setting of Setting2. Make it 3.0 or higher.
(9) Position settings. Enter the base station coordinates.

Next, the conventional survey by TS and level and the RTK-GNSS survey will be compared. The reference points and benchmarks set up in design work, etc., have a considerable period of time from design to ordering, and there is a possibility that the coordinate values of the reference points and the elevation of the benchmarks will deviate. Therefore, in the pre-construction survey, inspection surveys and cross-sectional surveys of reference points and benchmarks will be carried out. Here, after conducting an inspection survey of the construction reference point according to the TS and level and confirming the deviation, the problems in the work of the conventional survey by TS and level and the RTK-GNSS survey are compared for the cross-sectional survey.

In the inspection by TS in the inspection of the construction reference point, the construction reference point is usually set at the site by the 4th grade reference point survey. In order to confirm the coordinates, the TS was installed on the HT-11, and the existing reference point was observed by the radiation method with the HT10 as the rear viewpoint (Fig. 4). Table 3 shows the difference between the coordinates of the construction reference point and the inspection by TS observation. The distance of the construction reference point result (Fig. 5) was obtained by the net average, and was corrected by several mm to several cm to the measured value, which was also confirmed in the inspection results.

In the inspection by direct leveling, the elevation of the construction reference point is carried out by direct leveling, and in order to confirm the elevation of the existing reference point and clarify the problems of the on-site work, it was inspected by direct leveling. .. Starting from HT-10, the level was set in the center of the reference point, and round-trip observations to HT-13 were carried out. Since the distance marker 5/800 was inserted between HT-11 and HT-12 for observation (confirmation of consistency between the construction reference point and the existing point), the error was eliminated by setting the number of instrument installations to an even number in direct leveling. HT-14 is not observed because of the relationship. FIGS. 6 and 4 show the results of direct leveling and satisfy the accuracy of class 3 to 4 leveling.

The cross-sectional survey by RTK-GNSS will be described. Observation is possible by one person, but considering safety, it was carried out by two people. The time required for each point is 10 seconds for installation and 20 seconds for measurement, and the time required for installation can be reduced, which greatly improves the efficiency of measurement. In addition, if there are no vegetation that blocks satellite radio waves, there is no need for logging or weeding for visibility. On the contrary, if there is a place where satellite radio waves are reflected by mountains or buildings and generate multipaths that propagate through multiple routes, or if there are tall trees, slopes, structures, etc. that block the radio waves, the positioning error will be large. Since positioning becomes impossible, it is necessary to determine whether the conditions are suitable for RTK-GNSS and introduce it.

Next, positioning and data analysis by RTK-GNSS will be described. RTKLIB is used for the positioning calculation of RTK-GNSS. By the time the Fix solution that guarantees the positioning accuracy of several centimeters is obtained, a solution called the Float solution is obtained on the way until it converges on the Fix solution with the passage of time. If the distance between the base station and the mobile station is long, or if there are few common satellites with good reception between the base station and the mobile station, it takes a long time to derive the Fix solution, or the Fix solution cannot be obtained. Sometimes.

In reference point surveying, when using RTK-GNSS, after measuring one new reference point, measure the same point (constituent point) again and see the difference between one measured value for the same point. The procedure is to check if the value is an abnormal value. However, when RTK-GNSS is used for finished product measurement, the work efficiency, which is the merit of RTK-GNSS, can be expected to be halved and the introduction effect can be expected by the method of returning to the first measurement point and re-measuring after one measurement. It disappears. As an alternative measure for confirming the measurement accuracy, a method of periodically measuring a known point in the middle of the measurement route to confirm the measurement accuracy is certain at present. Therefore, the construction reference point was measured using this low-cost RTK-GNSS and its accuracy was verified. The method described below is the concept of accuracy confirmation, not a simple comparison method with known results. However, the accuracy was confirmed during the actual work by the magnitude of the coordinate deviation in consideration of speed and efficiency.

(1) In the result of the construction reference point, the distance between the points is corrected by about 10 mm to the measured distance between each point by the strict net average (see Fig. 5). That is, it is considered that the construction reference point itself has an error of 10 mm or more.
(2) Therefore, in order to confirm the construction reference point, TS was installed on HT-11, and the coordinates of HT-12, HT-13 and HT-14 were radiated and observed with HT-10 as the rear viewpoint (Fig.). 4). Although an error in inspection is possible, it was confirmed from this result (see Table 4 above) that there is an error of 10 mm or more in the horizontal position of the existing point.
(3) Next, the construction reference point was observed by RTK-GNSS. The results are shown in Table 5.

From the average deviation in this table, the difference between the RTK and the existing reference point is a maximum of 25 mm at the X coordinate, 17 mm at the Y coordinate, and 6 mm at H (elevation).
(4) In satellite positioning, the coordinate system at the site and the GNSS coordinate system are different, so it is not possible to simply compare by the coordinate difference. Furthermore, even from the above results, it is not appropriate to judge the accuracy based on the coordinate difference from the reference point. Therefore, the distance was obtained from the positioning coordinate values of RTK-GNSS, and the difference from the measured distance of TS was calculated (Table 6). Distances should be compared at diagonal distances as much as possible.

The distance difference ΔS of HT-13 is a little large, but other than that, the nominal measurement accuracy ± (20 mm + 2 x ^10-6 x D) D is in the km unit, and sufficient accuracy equal to or higher than that of expensive VRS can be obtained. There is. The elevation difference ΔH is obtained by subtracting the result (direct leveling) from the observed value of RTK-GNSS, but the accuracy of the elevation is equal to or higher than the accuracy of the horizontal position. It has been confirmed that the altitude accuracy is also good in the observation when setting the coordinates of the base station. It is presumed that the number of satellites that can be received by becoming a multi-GNSS receiver increased and the VDOP became low, and the accuracy was extremely good.

Regarding the effect on positioning accuracy due to the difference in distance between the base station and the mobile station, the fixed base station (Isa station) 1.1 km away from the trial site and the fixed base station (Aira station) 36.5 km away from the trial site (Fig. 6). Then, based on the on-site base station installed in the trial site, the construction reference point was measured, and the influence on the accuracy due to the difference in the distance from the base station was confirmed (Fig. 7, Fig. 8, Table 7, Table 8). .. The accuracy is determined by the distance deviation and the altitude deviation, and the numerical values in each table are values based on the reference point HI-10. From this result, the accuracy of the horizontal position (distance) was within 2 cm regardless of the distance from the base station, and there was almost no effect on the accuracy even if the Sora station, which was 36.5 km away, was used as the base station. .. The altitude accuracy of the on-site base station was within 1 cm, and there was no significant difference between the Isa station, which is 1.1 km away, and the Aira station, which is 36.5 km away. However, the fixed base station has the shortest Fix time of several seconds. The Isa station 1.1 km away took about 10 seconds, and the Aira station 36.5 km away took about 30 seconds, and the ratio did not rise to 999.9 during positioning.

In satellite positioning, since the on-site coordinate system and the GNSS coordinate system are different, it is necessary to perform localization (coordinate conversion) to convert the GNSS coordinate system into the on-site coordinate system (Fig. 9). If it is set first at the site, the measured values converted to the coordinates of the site will be displayed by using the setting during the subsequent construction period. The measured value of RTK-GNSS fluctuates by more than ± 1 cm. Therefore, it is considered that the measurement accuracy at the time of localization affects the measurement accuracy of the entire subsequent measurement. As a countermeasure, it is considered that the accuracy of the entire measurement can be ensured by performing the measurement at a known point for localization at a time zone with high accuracy or by taking a long time. The flow of the localization program is shown in FIG.

In FIGS. 11 to 13, the construction reference points set by TS observation were observed 5 times with RTK-GNSS at different times, and the observed coordinate values of TS were subtracted from the observed coordinate values of RTK-GNSS. , Y, H. The RTK-GNSS base station was installed at the reference point HT-2, about 500 m southeast of the center of the site. The difference between the XY coordinates was about 3 cm on average, and the difference between the maximum value and the minimum value was about 10 cm. In addition, there was a tendency to increase to the right as the distance from the reference station increased. The difference in elevation values was large over all points in the first observation, and was extremely large, especially at point HT-4, at 35 cm. There is a possibility of Miss Fix. In other observations, the difference between the maximum and minimum values was about 3 cm. FIG. 14 is a vector diagram showing the deviation of the horizontal position of each point obtained by the first RTK-GNSS observation value. The point HT-14 is the farthest from the reference station, but except for the first three points, the amount of deviation increases as the distance from the reference station increases, and the TS tends to shift while rotating counterclockwise from the southeast direction. It is considered that there is an influence due to the difference between the coordinate system and the RTK-GNSS coordinate system. FIG. 15 shows the X-direction movement amount: + 4 mm, the Y-direction movement amount: -10 mm, the rotation angle: -20 ", and expansion / contraction based on the east end point HT-2, the center point HT-8, and the west end point HT-14. It is a vector diagram which performed Helmart conversion at a rate of 1.000003. After the conversion, the deviation is about 10 mm as a whole.

In addition, a ready-made survey and a UAV aerial survey by RTK-GNSS will be described. The UAV aerial survey depends on the performance of the UAV camera, but with the camera equivalent to the UAV (Mavic 2pro manufactured by DJI) used here, when a still image is taken at an altitude of 40 m to the ground and made three-dimensional, the accuracy is about 10 cm. It has been confirmed that it can be measured. UAV aerial surveying requires a reference point called a control point on the ground, and conventional surveying was done with TS, but with RTK-GNSS, positioning of 20 seconds per point is sufficient, and the final Not only as-built surveying but also daily as-built surveying is possible, and the effect of introducing RTK-GNSS can be expected. According to the "Public Survey Manual Using UAV (Revised March 2017)", the distance between the outer control points is within 100 m, and when applied to this trial site, it will be within 10 points including the verification points. .. Here, the measurement of the station as shown in FIG. 16, including the finished product measurement, could be completed in about 2 hours. The order of work when carrying out daily finished survey by UAV aerial photography is that after installing the anti-aircraft sign, UAV aerial photography and control point measurement by RTK-GNSS are efficient, and aerial photography in a bright time before sunset. It can be done (Fig. 17).

As shown in FIG. 18, the UAV aerial survey is a shooting position / course when shooting at an altitude of 40 m above the ground, an overlap of 80%, and a side raf of 60%. The flight course was set in the vertical and horizontal directions so that there would be no omission of photography, the flight time was 10 minutes, and the total number of photographs was 420. As the SfM processing software, Metashape manufactured by Agisoft was used. FIG. 19 is SfM (three-dimensional reconstruction). Further, FIG. 20 is an orthophotograph, and various visual information obtained by the UAV aerial survey is also effective for daily confirmation of the finished product. However, 3D software that can be used online is still expensive and cannot be said to be widespread. Therefore, we have made it possible to share 3D point cloud data by using Potree, which is a point cloud viewer system that can handle 3D and point cloud data on a browser. Although FIG. 21 is a Portree screen, distances, areas, volumes, cross-sectional views, and the like can also be created. Note that Potree has been developed on GitHub, and data can be exported from Metashape.

In addition, the local topography (finished form) was randomly measured by RTK-GNSS, and the point cloud data of the three-dimensional coordinate values was acquired. In order not to disturb the finished surface of the construction as much as possible, one point of data was acquired every 1 m on the slope conversion line. ArcGIS was used for 3D data processing.

Data acquisition FIG. 22 shows a log of about 1 hour while walking at a distance of about 1 m / sec while holding RTK-GNSS. It was received in a fixed state based on a fixed base station, but data loss was observed for several seconds. It is presumed that the Wi-Fi radio wave of the fixed base station was interrupted.

FIG. 23 is a diagram made by two-dimensional CAD software (JW CAD) based on the log data. In addition, FIG. 24 is a 3D display by the Arc Scene of Esri's ArcGIS. ArcScene can also process UAV 3D point cloud data, it is easy to create cross-sectional views, and it is necessary to confirm the expansion accuracy, but I think that it can also be used for finished product management. Even the freeware QGIS, which has the same function as ArcGIS, can display three dimensions in the same way as ArcGIS 1S.

Next, regarding the improvement of RTKLIB and the software development of RTK-GNSS, the analysis program used is "RTKLIB ver. 2.4.3]. The patch program of various changes is provided by the program developer, and rtklib. The one provided in -2.4.3-b33 was used. However, since it was not developed only for the purpose of surveying, it is indispensable to improve RTKLIB and develop software for post-processing. ..

In RTKLIB (rtknavi), the latitude and longitude conversion display of WGS84 is possible from the earth center / earth fixed Cartesian coordinate system, but there is no function to convert to plane orthogonal coordinates. To convert to plane rectangular coordinates, the "Surveying calculation site" of the Geographical Survey Institute will be used, but since coordinate values may be required in real time at the site, it has been improved so that plane rectangular coordinates can be displayed.

Regarding the conversion program from latitude and longitude to plane rectangular coordinates, the improvement of RTKLIB (rtknavi) is only the plane orthogonal coordinate display, and the solution is saved as latitude and longitude. It is possible to use the "Surveying calculation site" of the Geographical Survey Institute, but the format of the log file of the solution of RTKLIB does not support it, and it must be processed manually. Therefore, we created a WEB program that can be downloaded by CSV by batch converting the Cartesian solution file to Cartesian coordinates.

Regarding the reverse hit point conversion (data creation for finished form evaluation) program, RTKLIB can read a GPX (GPs eXchange Form) file, which is a standard format for exchanging GPS data. This program can be used as 3D performance evaluation data by converting the basic design data into a GPX file and reading it into RTK-GNSS.

Further, when the RTKLIB is calculated as an RTK kinematic, the coordinates of the base station are input in degrees (decimal) instead of degrees, minutes, and seconds (sexagesimal). When converted with a calculator or the like, the second place can only be converted to the first decimal place, and if it is used as it is, a large error will occur. In order to input with an accuracy of 1 mm above the ground, numerical values of 5th and 6th place are required in seconds or less. This program is a WEB program that converts 5th and 6th data in seconds or less without losing digits.

This program is a localization program that translates 1 point, translates when inputting point coordinates, Helmart conversion when inputting 2 to 3 reference point coordinates, and affin conversion when inputting 4 or more reference point coordinates. At present, it is a post-processing calculation.

The invention's effect

The combination of the u-blox dual-frequency receiver ZED-F9P, which is a multi-band GNSS module used for measurement, and the analysis calculation software RTKLIB, obtained sufficient accuracy comparable to that of expensive VRS. In particular, the accuracy of altitude is said to be inferior to the accuracy of horizontal position, but the verification results when a base station was placed in the field showed extremely high accuracy within 1 cm. It is close to the vertical accuracy (within ± 10 mm in the vertical direction) required for shape management, and if the measurement method is devised, it is possible that the "height complement function" will not be necessary. It was verified that the effect of time reduction is also significantly reduced compared to the conventional technology. Since RTK-GNSS can be measured by one person, high work efficiency can be obtained. The method of positioning based on a fixed base station with RTK-GNSS is considered to be equivalent to the method of using a virtual reference point as a base station in VRS. Furthermore, the introduction cost can be suppressed. However, the same can be said for VRS, but in places where the Internet is not connected, such as in mountainous areas, it is necessary to perform positioning by wireless communication as before. RTK-GNSS positioning uses two receivers, a base station and a mobile station, but in order to exchange information between the two points in real time, a dedicated NTRIP Caster was built on the VPS (Virtual Private Server). The base station 40 and the mobile station 100 can be used at the same time.

In the present invention, by constructing a dedicated NTRIP Castor that exchanges information between two points between a base station and a mobile station, transmission / reception of GNSS observation data and correction data can be realized via the Internet, and can be continued inexpensively. It is possible to provide a low-cost RTK-GNSS that enables stable operation.

Further, in the present invention, by achieving consistency between the public reference point and the reference point, it is possible to confirm the positioning observation result in real time and shorten the work process using a conventional surveying instrument or the like.

Further, in the present invention, the price of the receiver is reduced, the receiver can receive two frequencies of the L1 band and the L2 band, the position calculation is quick, and the error of the positioning position due to the reception condition is reduced. ..

Further, in the present invention, by achieving consistency between the public reference point and the reference point, it is possible to confirm the positioning observation result in real time and shorten the work process using a conventional surveying instrument or the like.

Further, in the present invention, the system can be always operated without updating the system as compared with Windows, and can be obtained at a low cost.

Schematic diagram of the NTRIP method of the present invention Fixed base station installation method block diagram Map of the installed base station and 10km range Inspection map by TS Explanatory drawing showing a part of construction reference point results Explanatory diagram showing the results of direct leveling Map showing the distance from the base station Explanatory diagram showing the deviation of the distance from the base station Explanatory diagram showing the deviation of altitude from the base station Image of localization Localization program flow Explanatory diagram showing the difference of X coordinates Explanatory drawing showing the difference of Y coordinates Explanatory diagram showing the difference in H (elevation) Explanatory diagram showing the horizontal position difference between TS observation and RTK-GNSS observation Vector diagram after Helmart conversion As-built survey by RTK-GNSS and control point installation trajectory Block diagram showing the flow of UAV aerial photography and control point surveying Shooting course and shooting position (blue) SfM (MVS) seen from an angle Orthophoto (ortho image) Potree screen to share daily work on WEB Get logs while moving at a distance of about Im / sec (1 epoch / sec) Graphical by 2D CAD Three-dimensionalization by ArcG1S Explanatory drawing to estimate the position of the receiver by the principle of conventional triangulation Classification explanatory diagram of conventional GNSS survey Conventional single positioning explanatory diagram Conventional relative positioning explanatory diagram Conventional DGNSS positioning explanatory diagram Conventional interference positioning explanatory diagram Conventional RTK-GNN positioning explanatory diagram Conventional network type RTK-GNSS positioning explanatory diagram Explanatory drawing showing the principle of the conventional RTK-GNSS

Claims (4)

NTRIP that has two receivers, a base station and a mobile station, and realizes transmission and reception of GNSS observation data and correction data that exchange information between these two points in real time via the Internet. The data received at the base station is transmitted to the TCP Server called NTRIP Castor via the Internet, and the mobile station side connects to the NTRIP Castor to receive and analyze the data. VPS (virtual only) Install and operate the NTRIP Castor software on the server) to receive common satellite radio waves from both the mobile station for positioning and the base station at a short distance, and the fixed base station has a dual-frequency multi-GNSS receiver. A low-cost RTK equipped with a multi-band GNSS module that is a receiving chip and measures the time of transmission and the time of arrival to determine the position of the observation point based on the principle of triangular measurement for the distance from multiple satellites. -GNSS. The temporary coordinates of the second fixed base station obtained from the fixed base station are positioned by the mobile station, the obtained coordinates are used as the temporary coordinates of the second fixed base station, and the temporary coordinates of the second fixed base station are used in the vicinity. By positioning the public reference point or the reference point of the above, and correcting and correcting the deviation between the coordinates of the public reference point measured by the mobile station and the coordinates obtained from the second fixed base station, the public reference point and A low-cost RTK-GNSS that is consistent with the reference point, thereby determining the coordinates of the center of the antenna of the fixed base station on the earth and improving the consistency between the public coordinates and the reference point. The fixed base station consists of an antenna, a receiver, a personal computer, a wireless LAN (Wi-Fi router), etc., and the receiver uses a board on which a multi-band GNSS module, which is a dual-frequency multi-GNSS receiving chip, is equipped with a ZED-F9P module. The low-cost RTK-GNSS according to claim 1 or 2 above. The low-cost RTK-GNSS according to claim 1 to 3, wherein the deviation between the coordinates of a plurality of public reference points and the coordinates obtained from the second fixed base station is corrected and corrected.

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