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 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.
© 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 point of F9P as an RTK reference station. Tutorial of using this reference station is also available.
| Mount point | F9P | ROV |
|---|---|---|
| Protocol | RTCM 3.2 | RTCM 3.2 |
| Frequency band｜L1 and L2 | L1 | |
| Antenna position | Latitude 34.44010565 N Longitude 132.41478259 E Ellipsoidal height 233.057 m | Latitude 34.44010 N Longitude 132.41478 Ellipsoidal height 232.4 m |
| Satellite systems | GPS, GAL, GLO, QZS, BDS, SBAS | GPS, GAL, GLO, QZS, SBAS |
| Equipment | u-blox ZED-F9P Javad GrAnt-G5T | u-blox NEO-M8T (Emlid Reach) Tallysman TW-4721 |
| Comment | RTK 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 on June 19, 2019 using MADOCA-PPP. 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 | Mount point F9P | Mount point ROV |
|---|---|---|---|
| 1005 | Station coordinates XYZ for antenna reference point and antenna height. | 10 | |
| 1019 | GPS Ephemeris | 10 | 10 |
| 1020 | GLONASS Ephemeris | 10 | 10 |
| 1042 | BDS Ephemeris | 10 | |
| 1044 | QZSS Ephemeris | 10 | 10 |
| 1045 | Galileo Ephemeris F | 10 | 10 |
| 1046 | Galileo Ephemeris I | 10 | 10 |
| 1077 | GPS MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution) | 1 | 0.2 |
| 1087 | GLONASS MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution) | 1 | 0.2 |
| 1097 | Galileo MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution) | 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 | 0.2 |
| 1127 | BeiDou MSM7 (Full pseudo-ranges, carrier phases, Doppler and signal strength, high resolution) | 1 |
Tutorial is presented for using famous freeware RTKLIB.
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.