RTK reference station


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 portntrip.phys.info.hiroshima-cu.ac.jp:80
Service typeNTRIP Caster (version 1)
User namenone (blank)
ProtocolRTCM 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 pointOEM7F9PROV
ProtocolRTCM 3.2RTCM 3.2RTCM 3.2
Frequency band|L1, L2, and L5L1 and L2L1
Antenna positionLatitude 34.4401061 N
Longitude 132.4147804 E
Ellipsoidal height 233.362 m
same as leftLatitude 34.44010 N
Longitude 132.41478
Ellipsoidal height 232.4 m
Satellite systemsGPS, GAL, GLO, QZS, BDS, SBASsame as leftGPS, GAL, GLO, QZS, SBAS
EquipmentRTKLIB 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
Commentreference stationreference stationrover 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:

1005Station coordinates XYZ for antenna reference point and antenna height.1010
1019GPS Ephemeris101010
1020GLONASS Ephemeris101010
1033Receiver and antenna descriptor1010
1042BDS Ephemeris1010
1044QZSS Ephemeris101010
1045Galileo Ephemeris F101010
1046Galileo Ephemeris I101010
1077GPS MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution)110.2
1087GLONASS MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution)110.2
1097Galileo MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution)110.2
1107SBAS MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution)10.2
1117QZSS MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution)110.2
1127BeiDou MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution)11

Tutorial is presented for using famous freeware RTKLIB.

Observation data archive

You can obtain the archive data from below address:

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.