KR20190070696A - PPP-RTK Service Method for Port Navigation using State Space Representation in DGNSS Medium Frequency Wave - Google Patents

Abstract

The present invention relates to a precise point positioning-real time kinematic (PPP-RTK) service system for port navigation using state space representation in a differential global navigation satellite system (DGNSS) medium wave which provides a PPT-RTK service. The PPP-RTK service system for port navigation using state space information in a DGNSS medium wave comprises: a DGNSS reference station for receiving available data by using a GPS signal received from a satellite and generating differential global positioning system (DGPS) pseudo range correction (PRC) and state space representation (SSR) messages; a DGNSS data format processing unit for receiving PRC and SSR messages from the DGNSS reference station to perform a formatting process; a modulation unit for modulating data processed by the DGNSS data format processing unit; and a data link transmitter for transmitting the modulated data to a desired client side. Therefore, a PPP-RTK service can be provided.

Description

[0001] The present invention relates to a position-independent real-time service system for port navigation using state space information in a DGNSS medium wave.

The present invention relates to a precision autonomous positioning-real-time service system for port navigation using state space information in DGNSS (Medium Global Navigation Satellite System) medium, and more particularly, to a precision single positioning- Real-time service system for port navigation using state-space information in DGNSS intermediate-frequency waves serviced by Positioning-RealTime Kinematic, PPP-RTK.

Accurate positioning techniques to meet PNT (position, navigation, time) information requirements for position and navigation in recent marine applications have received international attention. In particular, the horizontal position accuracy requirements of IMO resolution A.915 (22) for port navigation present marine policy and the requirement for future GNSS is 1 m.

Automatic docking, water level survey, dredging, construction and cargo handling applications require accurate location services. RTK (Real-Time Kinematic), a precise positioning service solution, has limited service coverage and two-way communication.

Conversely, the precise point positioning (RTK) technology, which incorporates the concept of RTK, uses unidirectional communication for satellite orbit and clock correction and has the advantages of wide coverage and absolute positioning. However, the Precise Stand-Alone Positioning (PPP-RTK) technology based on the RTK network (PPP-RTK) overcomes the RTK and PPP limitations and provides centimeter accuracy and short convergence times. PPP-RTK uses state-space information to remove individual GNSS errors in satellite orbit, satellite clock, ionosphere, and troposphere. The update rate of the State Space Representation (SSR) differs from each error factor, but within 3 hours for the satellite orbit and 10 seconds for the satellite clock.

IGN GNSS-05, USA (Proceedings of the 18th International Technical Meeting), pp. 159-164, pp. .) In the case of SSR (State Space Representation), the variable range can be chosen in relation to the expected range of individual physical error components. The bandwidth requirement for state space information for a service area of 1000 km x 1000 km is 1500 bps. Currently, the DGNSS service uses medium waves, so it can cover a very large area. There are 17 DGNSS reference stations in Korea, and DGNSS reference stations are broadcast nationwide and coastal. In particular, the service of DGNSS reference station uses medium wave and transmission rate is 200bps. The main task of the DGNSS reference station is to provide the pseudo range correction (PRC) of the GNSS.

Therefore, the correction age of the pseudo distance correction information is a very important factor. When state space information is transmitted with pseudorange correction (PRC) information, it necessarily affects the correction age of the pseudorange correction (PRC).

In other words, the horizontal accuracy of the system for port services in IMO resolution A.915 (22) requirement is one meter. Differential GNSS (Differential GNSS) generally uses a harbor navigation system and ensures meter-level accuracy. However, it does not guarantee 1m accuracy horizontally. In addition, RTKs that use carrier phase measurements and ensure level accuracy in centimeters have limited coverage.

Precision Unique Position-Real-Time Service (PPP-RTK) uses observations from a single receiver and provides additional information on individual GNSS errors in the Global Navigation Satellite System (GNSS) network.

1 is a system configuration diagram schematically showing a configuration of a general maritime precision position measuring system.

Referring to Fig. 1, various recent maritime precise positioning systems require a marine precision position with a horizontal accuracy of 10 cm. Current users typically use satellite calibration information through the International GNSS Service (IGS) website. However, IGS is mostly used in post-processing systems. Or the user uses satellite information through the International GNSS Service-Real Time Simulation (IGS-RTS). IGS-RTS is used in real-time or almost real-time systems. Satellite information is one of the status information for a particular GNSS error. Precise Point Positioning (PPP) systems generally use the Networked Transport of RTCM Via Internet Protocol (NTRIP) service through the Internet Protocol (RTCM). However, NTRIP service is not operated in port or marine environment. One of the other communication methods is satellite-based services, but these communication methods have the drawback of requiring additional cost and infrastructure.

2 is a diagram showing the current DGNSS infrastructure status in Korea.

Referring to FIG. 2, in the case of the Korean DGNSS infrastructure, there are 11 maritime reference stations and 10 maritime surveillance stations. The services of the Maritime Reference Bureau and the Surveillance Bureau can be up to 180 km from the coast. Therefore, the Maritime Reference Bureau is able to provide service to the coast of Korea and the ocean. There are also six inland reference stations and five inland monitoring stations. In addition, two Loran-C stations (Long Range Navigation-C Station) and two Loran-C monitoring stations are operated and controlled by one control station. The communication distance of the inland DGNSS reference station can be up to 70 km. Therefore, when an inland reference station can be used for communication, Korean users can receive communication services from anywhere in the country.

References 1: Gerhard W. Bbena, Martin Schmitz and Andreas Bagge (2005), "PPP-RTK: Precise Point Positioning Using State-Space Representation in RTK Networks", proceedings of 18th International Technical Meeting, ION GNSS-05, USA.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the conventional art and it is an object of the present invention to provide an apparatus and method for providing state space information through a DGNSS medium wave capable of serving as a precise point positioning real time kinematic (PPP-RTK) Real-time service system for the port navigation.

In addition, the present invention uses a minimum shift keying (MSK) modulator and a demodulator, which are directly connected to the experiment, to avoid the noise of medium waves. As a result, the validity of the state space information transmission through the medium wave, Real time service system is provided for port navigation using state space information in DGNSS intermediate frequency wave which can transmit data through medium wave and maximum pseudo distance correction age does not exceed 30 seconds. .

In order to accomplish the above object, the present invention provides a precision autonomous positioning-real-time service system for port navigation using state space information in a DGNSS medium wave, comprising: a DGNSS (Differential Global Navigation Satellite System) reference station for receiving data received from satellites; A DGNSS data format processing unit for generating and performing a DGPS (Differential Global Positioning System) pseudorange correction (PRC) and state space representation (SSR) message from the GPS information received from the DGNSS reference station; A modulator for modulating data processed by the DGNSS data format processor; And a data link transmitter for transmitting the modulated data to a desired client side.

The formatting process may be to use the 1060 message as GPS orbit and clock correction information to process the message type format.

In the message 1060, up to twelve satellite clock correction information and up to two satellite orbit correction information may be transmitted.

The correction information type 9 generated by the DGNSS reference station may be composed of a GPS partial correction information set.

The DGNSS reference station may be to broadcast correction information including state space information.

Therefore, the precision autonomous positioning-real-time service system for the port navigation using the state space information in the DGNSS medium-wave of the present invention can serve as a precise point positioning-real time kinematic (PPP-RTK) service.

In addition, the precision single positioning-real-time service system for port navigation using the DGNSS medium-frequency signal in the DGNSS medium-wave of the present invention is used to avoid the mid-wave noise due to a directly connected MSK (Minimum Shift Keying) modulator and demodulator, It is effective to verify the possibility of transmission of SSR information and PRC correction age through satellite, and to make accurate satellite orbit and satellite clock correction information broadcast through medium wave and maximum PRC correction age not exceeding 30 seconds.

1 is a system configuration diagram schematically showing a configuration of a general maritime precision position measuring system.
2 is a diagram showing the current DGNSS infrastructure status in Korea.
3 is a diagram illustrating an age of pseudo distance correction information according to an exemplary embodiment of the present invention.
4 is a diagram illustrating a configuration of a precision autonomous positioning-real-time service system for port navigation according to an embodiment of the present invention.
5 is a diagram illustrating a DGPS pseudorange correction value in a pseudo distance correction broadcasting only DGPS correction information according to an exemplary embodiment of the present invention;
6 is a diagram illustrating a DGPS horizontal error for broadcasting only DGPS correction information according to an embodiment of the present invention.
7 is a diagram illustrating a DGPS pseudorange correction value using correction information including state space information according to an exemplary embodiment of the present invention,
8 illustrates a DGPS horizontal error using correction information including state space information according to an embodiment of the present invention.
FIG. 9 is a diagram illustrating a precise autonomous positioning position error using an RTCM transmission service over an Internet protocol in accordance with an embodiment of the present invention; FIG.
FIG. 10 is a diagram illustrating a precision single positioning result using a message designed in a DGNSS medium frequency band for a satellite clock according to an embodiment of the present invention; FIG.

In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings showing embodiments of the present invention.

DGPS and RTK correction is the Observation Space Representation (OSR), a distance-dependent state parameter that is combined with the reference reference station. Therefore, it is necessary for each satellite and reference station. However, the correction information of PPP and PPP-RTK in independent navigation has satellite orbit, satellite clock, troposphere delay and ionospheric delay. They do not need to generate correction information for each reference station. This correction information is state space information (SSR). In the Radio Technical Commission for Maritime Service (RTCM) standard for maritime services, state space information (SSR) is an individual GNSS error component and provides all GNSS errors directly to the user. The state space information message enables basic PPP as shown in Table 1.

Message Type Message name 1057 SSR GPS orbital correction information 1058 About GPS Clock Calibration 1059 GPS code bias 1060 Combine GPS Track and Clock Compensation 1061 GPS URA (GPS user distance accuracy) 1062 About GPS High Speed Clock Calibration 1063 GLONASS Orbital Calibration Information 1064 About GLONASS Clock Calibration 1065 GLONASS code bias 1066 GLONASS Combined Orbit and Clock Calibration Information 1067 GLONASS URA (GPS user distance accuracy) 1068 GLONASS High Speed Clock Calibration Information

Multiple calibration services

The present invention proposes a port PPP-RTK service using DGNSS medium frequency wave in Korea.

The system can broadcast correction information including DGPS and state space information. Therefore, the user uses both DGNSS and PPP in the DGNSS communication range. The DGNSS reference station broadcasts the reference station location, signal status, and correction information as shown in Table 2 and broadcasts message types 1, 3, 5, 7, 9, and 18 in general.

Message type Current Status title One fixing About DGPS Calibration 3 fixing Location of GPS reference point 5 fixing GPS signal status 7 fixing DGPS Radio Beacon Alma Nakal 9 fixing GPS partial correction information set 18 fixing RTK uncorrected carrier phase

One of the representative DGPS calibration information messages is type 9. This message is partial pseudorange correction and pseudorange change rate correction information. Message type 9 is used for the same purpose as message type 1. Type 1 is a message containing all satellites. Type 9 is a maximum of three satellite messages taking into account the calibrated age.

3 is a diagram illustrating an age of pseudo distance correction information according to an exemplary embodiment of the present invention. 4 is a diagram illustrating a configuration of a precision autonomous positioning-real-time service system for a port navigation according to an embodiment of the present invention.

Referring to FIGS. 3 and 4, the correction age is the correction time difference between the past and the present in the same satellite.

Table 3 shows the age of pseudo range correction information at 100 bps.

Number of satellites Type 1 Type 9 4 5.4s 5.4s 6 7.2s 6.3s 8 9.6s 8.1s 9 10.2 8.4s

Transmission times between Type 1 and Type 9 are shown in Table 3. Table 3 shows that type 9 is faster than type 1. In Korea DGNSS infrastructure, type 9 pseudorange correction (PRC) transmission time corresponding to three satellites is almost 1.2 seconds, and type 9 PRC transmission time is less than 7s for 12 satellites. Thus, we can see that a minimum of 23 seconds is required.

Referring to FIGS. 3 and 4, the DGNSS reference station 20 receives GPS signals from the satellite 10.

The DGNSS reference station 20 generates the DGPS correction information pseudorange information and the state space information message using the GPS signal received from the satellite 10. The functions are shown in Tables 1 and 2 above. The DGNSS reference station 20 may broadcast correction information including state space information. The user uses both DGNSS and PPP in the DGNSS communication range.

The DGNSS reference station 20 broadcasts a message including the DGNSS correction information and the status space information message using the DGNSS medium wave. However, the system has three requirements: the age of the pseudorange correction (PRC) is less than 30 seconds, the satellite orbit correction information update is less than 3 hours, and the satellite clock correction information update is less than 10 seconds.

The DGNSS data format processing unit 30 received from the DGNSS reference station 20 receives the DGPS pseudorange correction and state space information message. The DGNSS data format processing unit 30 can format the 1060 message among the message types of Table 1 described above. The first step is a DGPS PRC message type 9 with maximum satellite 3 being transmitted. Up to twelve satellite clock correction information and up to two satellite orbit correction information were transmitted in SSR message 1060 (combining GPS track and clock correction). The last DGPS PRC message type 9 is sent again. Step 3 is a one cycle schedule of messages.

The data formatted message by the DGNSS data format processing unit 30 is modulated by the modulator 40 and the data link transmitter 50 and broadcasted to the client side. DGPS processing for 12 satellite sets requires 2 cycles and satellite clock correction information for 12 satellites requires 1 cycle. And the twelve satellite orbital correction information requires six cycles.

Two message simulation tests were performed to verify the proposed message design and scheduling. The first test is a test in an environment with a maximum of 12 satellites visible. The second test is provided as actual data at the Daejeon Ship Offshore Plant Research Institute (KRISO), the applicant of the present invention. Table 4 shows the message simulation test results.

Environment Requirements Number of external satellites Actual data Maximum value Average Number of satellites - 12 11 8 Age of pseudo distance correction <30s 17s 16s 10.6s Satellite Clock Update <= 10s 10s 9s 6.9s Satellite Orbit Update <3 hr 50s 57s 30s

For the maximum number of satellites, the age of the PRC is 17 seconds, the satellite clock update is 10 seconds, and the satellite orbital correction information update is 50 seconds. For real data, the maximum number of satellites is 11 and the average number of satellites is 8. The average age of the DGPS is 10.6 seconds, the average satellite clock correction information update is 6.9 seconds, and the average satellite orbital correction information update is 30 seconds. Therefore, we can confirm that this result meets the calibration age requirement.

The second verification test is the DGPS zero baseline test. A zero baseline test was performed to confirm the DGPS location accuracy by applying design messages.

FIG. 5 shows a DGPS pseudorange correction value for broadcasting only DGPS correction information according to an embodiment, and FIG. 6 shows a DGPS horizontal error for broadcasting only DGPS correction information according to an embodiment.

Referring to Figures 5 and 6, the horizontal error is RMS 3 cm. The resulting environment was targeted to one recipient. Therefore, the horizontal error is more accurate than the other zero baseline tests.

FIG. 7 shows a DGPS pseudorange correction value using correction information including SSR information according to an exemplary embodiment of the present invention. FIG. 8 is a diagram illustrating a DGPS pseudorange correction value using SSR information according to an exemplary embodiment of the present invention. Error.

Referring to FIGS. 7 and 8, the DGPS pseudorange correction value is shown in the message. The pseudo distance correction value is similar to Fig. However, in FIG. 7, since the PRC correction age increases, the number of correction information decreases. Figure 8 shows the DGPS horizontal error using the correction information including the state space information. The result is RMS 7 cm. The age of the pseudo distance correction information has increased, but the horizontal accuracy has met the port requirement of 10m.

The third test is the Precise Point Position (PPP) result. The PPP test was performed to apply the designed message. Mar, 17, 2017 and GMV (Global Mobile Vision) satellite information for one day on March 17, 2017 were used. The GMV data includes 1060 messages.

FIG. 9 is a diagram illustrating an accurate single positioning position error using an RTCM broadcast service over an Internet protocol according to an embodiment of the present invention. FIG. And Fig.

The error in Fig. 9 is less than 10 cm. The satellite orbital correction information is not used in the result of FIG. The horizontal error in FIG. 10 is 11 cm. This result almost met the port navigation requirement of 10 cm.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that various modifications may be made without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: Satellite 20: DGNSS reference station
30: DGNSS data format processing unit 40: Modulator
50: Data link transmitter

Claims (5)

A DGNSS (Differential Global Navigation Satellite System) reference station receiving a GPS signal from a satellite and generating a DGPS (Differential Global Positioning System) Pseudo Range Correction (PRC) and a State Space Representation (SSR) message;
A DGNSS data format processor for receiving and formatting the DGPS pseudorange correction and state space information message from the DGNSS reference station;
A modulator for modulating data processed by the DGNSS data format processor; And
And a data link transmitter for transmitting the modulated data to a desired client side, wherein the DGNSS is a precision autonomous positioning-real-time service system for port navigation using state space information in a medium wave. 2. The method of claim 1, wherein the formatted processing comprises processing a format of a message type and using a 1060 message as GPS orbit and clock correction information, wherein the DGNSS medium- Real-time service system. 3. The method of claim 2, wherein in the message 1060,
Real - time point - of - sale service system for port navigation using state space information in DGNSS medium - wave, including up to 12 satellite clock correction information and up to two satellite orbit correction information. The method according to claim 1,
The calibration information type 9, which is generated by the DGNSS reference station, consists of a set of GPS partial correction information. A precision autonomous positioning-real-time service system for port navigation using state space information in the DGNSS medium wave. The base station of claim 1, wherein the DGNSS-
A precise autonomous positioning - real - time service system for port navigation using state - space information in DGNSS medium - wave broadcasting calibration information including state - space information.

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