Frequently Asked Questions
RTN is a real time positioning network that provides centimeter or better accuracy in latitude, longitude, and 2-5 centimeter accuracy in ellipsoid height at any given time (barring geomagnetic storm/solar flare).
Montana State Reference Network (MTSRN)
March 12, 2022
RTN provides a common correction on national datum for the entire state with improved accuracy and fewer conversion errors. RTNs provide machine guidance for grading or superelevation and benefits construction and transportation for critical engineering infrastructure, land surveying, precision agriculture, energy and utility, mining, drones, robotics, public safety and more.
The State of Montana owns the MTSRN under the legal authority of the Montana State Library. The Montana Department of Transportation (MDT) is a major partner for establishing the bulk of base stations. The MTSRN is also partnered with Montana Tribal Nationals, city and county governments, and the University of Montana. 15 stations from UNAVCO have been added to the network as well.
MTSRN is run on Trimble's Pivot software which is hosted in Trimble's cloud server.
2011 realization of North American Datum of 1983 or NAD 83(2011), epoch 2010.0.
Yes, the default output of the MTSRN is latitude, longitude, and ellipsoid height. You need a National Geodetic Survey (NGS) geoid difference model installed in your software to receive orthometric height. We recommend using the latest geoid model which is GEOID18.
MTSRN provides RTN correction through NTRIP (Network Transport of RTCM via Internet Protocol) which supports wireless internet access through any mobile IP networks (GSM or CDMA). There are NTRIP clients in most survey/mapping grade rover receivers/data collectors with standard fields to enter NTRIP IP/Port along with login credentials. - Users can login to MTSRN website (www.mtsrn.org) using the same login credentials.
About 120 stations. However, the density of base stations may change depending on the NGS recommendations of spacing geometry, relief discrepancy (gravity dependent), and availability of construction sites and needs.
Long separation between stations prohibits creating network solution. Subnets are formed to create network solution using a cluster of closely spaced base stations.
There are currently five (5) subnets in the network. These are named geographically such as NEMT for northeast Montana or SCMT for southcentral Montana.
NEMT, NCMT, NWMT, SWMT, and SCMT
Virtual Reference Station (VRS) is a station created close to a Rover Receiver as if this virtual station is providing the correction to the rover.
A VRS solution format, or a single base broadcast format provided by NTRIP caster is called a mountpoint. An NTRIP client rover connects to a mountpoint and receives correction from the specific mountpoint.
VRS is the name of the network solution. VRS follows the subnet name, such as NEMTVRS or SCMTVRS. To differentiate between Trimble proprietary solution or international standard solution format suffixes are added. For example, CMRx is added (example: NWMTVRSCMRx) to indicate Trimble proprietary multi-constellation non-proprietary international solution format. International standard (RTCM3.1 - RTCM3.3) solution format is compatible for any rovers built in the last decade.
CMR+ and RTCM3.1 are Trimble proprietary and international solution formats respectively for GPS/GLONASS only receivers. In MTSRN, for example, mountpoint NEMTVRSCMR is added to indicate CMR+, and mountpoint NEMTVRSRTCM3 is added to indicate RTCM3.1 VRS solutions. For Single base solutions, BKFB is added to indicate CMR+ and BKFB_3 to indicate RTCM3.1 solution.
Training Resources
The video below provides helpful GIS/UAS trainings in the form of a webinar presented by the Montana State Library. This is video 1 in an 11 video series available on our YouTube channel.
The video below is a webinar training provided for land surveyors. This is video 1 in a 10 video series available on our YouTube channel.
MTSRN Coordinator
Kazi Arifuzzaman
Montana State Library
mtsrn@mt.gov
406-444-0240
