Montana State Reference Network



What is the MTSRN?

Montana State Reference Network (MTSRN) is the state owned real time positioning network, operated with the cooperation of partners that includes (but is not limited to), Tribal Nations, the Montana State Department of Transportation (MDT), Montana State Library (MSL), CORS of the National Geodetic Survey, scientific stations of the Earthscope Plate Boundary Observatory (PBO, operated by UNAVCO), Counties, Educational Institutions, and private entities who maintain, operate, or otherwise contribute to the operation of this statewide array of over 50 GNSS reference stations. These GPS/GNSS stations provide raw GNSS observation data for both development of real-time corrections and logging of static files for high precision positioning. Static data is free to the public, with real-time services available for authorized partners, or parties interested in possibly joining the MTSRN.

How the MTSRN Pilot Works

The MTSRN is a pilot, a test RTN was set up to operate during the first half of 2019 with the help of Washington State Reference Network (WSRN), and currently has been migrated to and launched from Montana owned server hosted at Trimble cloud service. It is a network of 50+ reference stations feeding raw observation data to the Montana State Reference Network (MTSRN). The raw GNSS observations are processed on MTSRN servers to create static files for download, and real-time corrections in standard formats. These are delivered by an 'NTRIP Caster'. This caster can allow thousands of users to request correction streams from a network through a single portal. This service is being made available to interested GPS/GNSS users for the period of the pilot. This service is non-proprietary. Your gear (unless very old) will be useable on the MTSRN: almost without exception, manufacturers of high precision GNSS field equipment (built in the past 10-15 years) supports the use of standard RTN correction streams and static files.

See current map of MTSRN (pdf). You can find other downloads on the website:

Real-Time Networks (RTN) - a Geospatial Amenity

There are over 400 Real-Time Networks (RTN) worldwide, some covering entire countries. Utilization is spreading beyond surveying and mapping to utilities, emergency response, agriculture, forestry, public safety, transportation, machine control for construction, environmental, and scientific research. Cost savings can be substantial. High accuracies are available, in real-time. By following proper procedures, users can observe locations (to centimeters) in seconds. Users are encouraged to take multiple measurements to ensure repeatable results.

Using the MTSRN Pilot - Post-Processing Users

If you are a GPS/GNSS post-processing user, you can go to the website and download static files from any of the stations in the pilot by choosing the 'Reference Data Shop'. You will need to choose 'Login' on the left side of this page, and then log in as a 'Guest'; put in 'guest' (all lowercase) in box for 'User name', and guestguest in box for 'Password'. Then choose 'Reference Data Shop' on the left side of the page. Follow the prompts to make custom data downloads for single, or groups of stations. You can choose different time periods, intervals, and data formats (Rinex, DAT, etc). When you make an order, take note of the order number. Depending on the size of the order, it could take as long as 30 minutes to process. You can always leave the page and log in later to look for your order number. The Reference Data Shop is simply a convenient way to make custom static file orders. You can also use post-processing service for your static files by choosing ‘Online Post Processing’ link on the page.

Using the MTSRN Pilot - Real-Time Users - Single Base

There are multiple options for using 'real-time corrections' from the MTSRN pilot. If you prefer, you can obtain singe base RTK corrections for an individual station (e.g. 'BKFB' in Browning). When you look at the NTRIP caster source table in your field rover data collector software you may see multiple entries for each station. These represent different correction 'flavors' you can choose from. If you see a 4-character station name with no suffix like 'BKFB', then it is outputting 'CMR+' (used by some older rovers). If you see a '3' suffix, like 'BKFB3' then it also has an RTCM3.1 output for GPS+GLONASS if that station is tracking both (see map). RTCM3.1 is a common international standard output compatible with nearly every rover built in the past 10 years. The results between CMR+ and RTCM3.1 will not be different, just different flavors for different rovers. If you see an 'MSM' or ‘CMRx’ suffix, it means that the station has multiple (3+) constellations: GPS+GLONASS+GALILEO+BEIDOU; the 'MSM output is RTCM3.2-MSM, and ‘CMRx output is Trimble proprietary’: if your rover supports multiple constellations, you will be able to use this to add the newer satellites to your RTK solution. Remember that single base solutions degrade over distance from a base, and from day to day as ionospheric and tropospheric conditions change. Network RTK (NRTK, VRS etc.) was developed (and has grown over the past 20+ years) to enable wider spacing of stations, and model out the iono and tropo.

Using the MTSRN Pilot - Real-Time Users - Network Solutions

There are multiple options for using 'real-time corrections' from the MTSRN pilot with 'network corrections' in addition to the single-base options outlined above. If you look at the MTSRN map you will see some small clusters of stations linked together. These are VRS 'subnets'. For instance, the NWMTVRSRTCM3 mountpoint is the VRS solution you can use in that subnet in the Blackfeet area. Eventually, when more stations are connected, the six subnet areas on the map (NE, NW, SC, NC, NE and SE) will have more stations in the respective VRS solutions. In the interim, if you are working inside an area of linked stations, you can use a network solution (e.g. NWMTVRSRTCM3), but if outside of those areas you should stick to single base solutions. When an entire state or subnet is covered with linked stations, many users only need to choose one mountpoint for all their work. During this pilot there may only be a few areas of network solution; it might take a while (and lots of partners) to build out the whole state. The naming convention for the VRS subnets is the area of the state (e.g., NWMT) plus the solution type (e.g., VRS) plus the correction format (e.g., RTCM3.2MSM). So 'NWMTVRS_MSM' is a VRS solution, output in RTCM3.2MSM with GPS+GLONASS+GALILEO+BEIDOU (if your rover supports multiple constellations). Network RTK has some advantages over single-base in that it can work further from a base, it can model-out changes in iono and tropo from day to day over a broad area; it works as if the base is very near to your location.

Geodetic Reference Framework - NAD83 (2011) epoch 2010.00

The geodetic policy of the MTSRN is to constrain all MTSRN stations to the National Spatial Reference System (NSRS) of the National Geodetic Survey (NGS). Some of the MTSRN stations are NGS CORS, and the rest are constrained to NGS CORS through a rigorous network adjustment. Note that many of the stations with 'P[number]' naming convention (e.g. Earthscope Plate Boundary Observatory, or 'PBO' stations like P047 and P722) are already NGS CORS, and many of the MDT stations (most are prefixed with 'MT') have been submitted to the NGS for inclusion as NGS CORS and have just been accepted. All non-CORS stations have been rigorously constrained to existing CORS.

By default, GNSS rovers output ellipsoid heights. With a geoid model (e.g., GEOID18) applied on your field rover software you can output NAVD 88 orthometric heights. The geoid application does NOT happen on the RTN side. The same goes for 'state plane coordinates'. The MTSRN does not (nor any RTN) broadcast 'state plane coordinate' references; those are derived/projected in your data collector or office software. Consult your rover vendor for settings specifics - the MTSRN does NOT support your hardware and software.

MTSRN Partnerships & Sustainability

The MTSRN is just a pilot at this time. The idea behind this pilot is to demonstrate the viability of an RTN for Montana, and to help the interested parties find more partners, and the backing needed from Federal and State agencies as well as Private parties to establish a sustainable RTN in MT.

If you would like to have your organization or company join in and help this initiative move forward, contact Kazi - see contact info below:

Kazi Arifuzzaman is the Montana RTN Coordinator. Contact him: -

Like to host, or help find a site for a new reference station?

If you see a hole in the current status map of Montana and have a potential reference station site in mind (even if only temporarily to help with the MTSRN pilot) please contact us. If you have a stable place to mount an antenna (bedrock or non-alluvial stable ground on which to construct a pillar or drill brace mount, or a solid, preferably single-story building, or other solid structure to mount an antenna, contact us. It could be your business location, local school, or other facility as long as there is reliable power (120V 5A is sufficient) and some means to get the data to the internet. There are lots of options that do not require firewall holes, like your own Wifi router.

Like to try out the MTSRN?

Pilot Login Requests:


Use of MTSRN pilot services, applications and features of this website, or any information contained on this website or through any links provided on this website is at the user's sole risk. The MTSRN, MTSRN partners and MSL provides MTSRN Services on an 'as is' basis. Neither MTSRN members, nor MSL, its officers, employees, vendors, or third-party service providers (collectively or individually) makes any express or implied representation or warranty of any kind with respect to MTSRN Services. By way of example and not of limitation, there is no representation or warranty (a) that MTSRN Services will be uninterrupted or error-free, (b) that the results obtained from using MTSRN Services will be accurate, reliable, complete or current, or (c) of merchantability or fitness for a particular purpose. MTSRN Services and information related thereto are subject to change without prior notice.

Neither MSL nor the subscriber, or MTSRN members, is liable for any damages arising out of or in connection with MTSRN Pilot and MTSRN Services, including without limitation mistakes, omissions, interruptions, deletion of files, errors, defects, viruses, delays in operation or transmission, or failures of the Continuously Operating Reference Stations (CORS). This is a comprehensive limitation of liability that applies to all damages of any kind, including compensatory, direct, indirect or consequential damages, loss of data, income or profit, loss of or damage to property and claims of third parties.


Acknowledgment: WSRN operator, Mr. Gavin Schrock