RTK reference station

Summary

A RTK (realtime kinematic) reference station is in operation at Hiroshima City University. Real-time centimeter-order positioning can be expected using the observation data of the RTK reference station. For real-time positioning with the observation data, you may need a receiver measuring the carrier phase and an internet connection.

The observation data can be used for free without any prior notice. Please note that the service may be interrupted due to the software updates, equipment failures, power outages, and so on.

The observation data cannot be used for official surveying.

RTK reference station

RTK would be available at a location about 10 km from the reference station. You may use the observation data in most of places of central Hiroshima.

circle of 10 km from the reference station

© OpenStreetMap contributors

You may find more RTK reference stations at Volunteer RTK reference stations other than this reference station.

Information for connection

Details are as follows:

address and port ntrip.phys.info.hiroshima-cu.ac.jp:80
Service type NTRIP Caster (version 1)
User name none (blank)
Password none(blank)
Protocol RTCM 3.2

Following mount points are in public. Please use the mount point of OEM7 or F9P as an RTK reference station. Tutorial of using this reference station is also available.

Mount point OEM7 F9P ROV
Protocol RTCM 3.2 RTCM 3.2 RTCM 3.2
Frequency band|L1, L2, and L5 L1 and L2 L1
Antenna position Latitude 34.4401061 N
Longitude 132.4147804 E
Ellipsoidal height 233.362 m
same as left Latitude 34.44010 N
Longitude 132.41478
Ellipsoidal height 232.4 m
Satellite systems GPS, GAL, GLO, QZS, BDS, SBAS same as left GPS, GAL, GLO, QZS, SBAS
Equipment RTKLIB 2.4.3b34
u-blox ZED-F9P
Javad GrAnt-G5T
RTKLIB 2.4.3b34
NovAtel OEM729
Javad GrAnt-G5T
RTKLIB 2.4.3b34
u-blox NEO-M8T (Emlid Reach)
Beitian BT-200
Comment reference station reference station rover station

Mount point F9PR is also broadcasted for the u-blox raw message regarding the mount point F9P. The antenna positions were determined using GSI CORS Hiroshima 2A station on March 13rd - 17th 2021 (updated on 2021-03-27). The antennas are on the top of the Information Processing Center at Hiroshima City University (3-4-1 Ozuka-Higashi, Asa-Minami, Hiroshima, Japan).

The RTCM messages broadcasted from the server are as follows:

Type Description OEM7 F9P ROV
1005 Station coordinates XYZ for antenna reference point and antenna height. 10 10
1019 GPS Ephemeris 10 10 10
1020 GLONASS Ephemeris 10 10 10
1033 Receiver and antenna descriptor 10 10
1042 BDS Ephemeris 10 10
1044 QZSS Ephemeris 10 10 10
1045 Galileo Ephemeris F 10 10 10
1046 Galileo Ephemeris I 10 10 10
1077 GPS MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution) 1 1 0.2
1087 GLONASS MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution) 1 1 0.2
1097 Galileo MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution) 1 1 0.2
1107 SBAS MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution) 1 0.2
1117 QZSS MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution) 1 1 0.2
1127 BeiDou MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution) 1 1

Tutorial is presented for using famous freeware RTKLIB.

Observation data archive

You can obtain the archive data from below address:

https://phys.info.hiroshima-cu.ac.jp/gnss/f9p/
https://phys.info.hiroshima-cu.ac.jp/gnss/oem7/
The URI error regarding OEM729 archive was corrected on 2021-04-17

What is GNSS, and why RTK

As positioning satellites, not only GPS (Global Positioning System) in the US but also GLONASS in Russia, Galileo in the European Union, BeiDou in China, and Quasi-Zenith Satellite System (QZSS) in Japan can also be used. These positioning satellites are collectively called GNSS (Global Navigation Satellite System). Anyone can use these satellite signals free of charge. If more satellites are available, the validity and availability of the positioning results will increase. NAVIC (Navigation for Indian Constellation) in India is expected to be available as GNSS soon.

RTK is a method that aims at positioning with a precision of several centimeters at a mobile station using GNSS radio wave observation results at a “reference station” with known latitude and longitude. GNSS signal observation results at the reference station are transmitted to the mobile station via the Internet or mobile radio communication. On the other hand, the GNSS signal is also observed at the mobile station, and the uncertainty of the positioning result at the mobile station can be reduced by correcting the observation result at the mobile station or elsewhere.