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Real-time GNSS Correctors

Oregon Real-time GNSS Network (ORGN) partners and subscribers with valid ORGN Rover Accounts have access to Real-Time Kinematic (RTK) correctors computed by Leica Spider software. These correctors are served over the internet and accessed by the user via a cell modem connected to a GNSS rover in the field.
ORGN Spider provides Network multi-base correctors on ports 9881 (GPS) and 9882 (GNSS). Single Reference Station survey accuracy (dual-frequency) correctors on port 9879.  In addition, a single frequency GPS-only corrector is provided for users of resource/mapping accuracy GPS receivers; however, most current resource accuracy receivers can utilize all correctors provided by the ORGN.
 
Network RTK Corrections:
 
A network-based RTK corrector is based on using several reference stations to compute the corrector.  A network-based corrector resolves distance dependent errors including ionospheric, tropospheric, and emphemeris errors better than a corrector based upon a single reference station, thereby allowing the rover user to travel farther from any single reference station than would be possible when using a single reference station.
 
A user must be within or only slightly outside the confines of the network for a network-based corrector to be effective.
 
ORGN provides a network corrector called MAX, in the non-proprietary RTCM version 3.x format, to rovers that are RTCM 3.x-capable.  The MAX network correctors take full advantage of the additional network messages available in the RTCM 3.x format.
 
For older GPS rovers that are not version RTCM 3.x-capable, a network corrector called i-MAX is provided using the non-proprietary RTCM 2.3 format.
 
For a rover to use either the MAX or i-MAX network corrector, it must be configured by the user to send the rover position back to the ORGN server using the NMEA GGA format.  In other words, the rover must be set to "send GGA".
 
Single Reference Station RTK Corrections:
 
If the user is working very far outside the confines of the RTK network, they will not be able to use a network-based correction effectively; however, rover users will still be able to receive a corrector based upon a single reference station up to about 10 Km from the single base they are receiving correctors from.  The same distance dependent errors apply as when using a single base RTK from a temporary base station, so the users must take the responsibility to ensure they don't travel so far from a single base that they exceed their error budget on a project.  Even though the user of a single base station solution will not be able to work as far from the reference station as when using a network-based MAX or i-MAX solution, the user will still realize considerable cost savings by not having to buy a base station receiver and set it up and monitor it everyday of a project.  In addition, common error sources associated with the use of a portable base station, including incorrect input of base coordinates, base antenna not plumbed correctly over station mark, and incorrect height of base antenna, are avoided by the use of a permanent ORGN reference station.
 
ORGN provides "nearest site" RTK correctors in the non-proprietary RTCM 2.3 format.
 
For a rover to use the "nearest site" RTK correctors, it must be configured by the user to send the rover position back to the ORGN processing center using the NMEA GGA format.  In other words, the rover must be set to "send GGA".
 
DGPS:
 
Resource-grade mapping GNSS users can access RTCM correctors from the ORGN GNSS network via cell phone modem.
 
ORGN provides single frequency "nearest site" RTCM correctors for mapping resource GNSS receivers in the non-proprietary RTCM 2.3 format; however, most current resource accuracy receivers can utilize all correctors provided by the ORGN.
 
For a single frequency GNSS receiver to use the "nearest site" RTK correctors, it must be configured by the user to send the rover position back to the ORGN processing center using the NMEA GGA format.  For example, for the Trimble GeoXT, the RT corrector type should be set to "VRS" under RT settings/External Port Settings in order to send GGA.
 
ORGN Rover Accounts: Partner/Subscriber Information
 
Real-time correction products will be provided to users with valid Rover Accounts.
 
 All rover users will be issued a Rover Account at no direct charge; however, ODOT reserves the right to charge a nominal Rover Account fee in the future to cover operations and maintenance of the ORGN only, not to cover development costs of the ORGN.   In the event that ODOT must start charging for Rover Accounts, ORGN partners will continue to receive Rover Accounts at no charge.
 
A partner is defined as an individual, agency, or business that contributes substantially to the infrastructure of the Oregon Real-time GNSS Network (ORGN).  An individual, agency or business may qualify as a partner of the ORGN by providing a GNSS reference sensor and antenna  and/or a site for a reference station for the ORGN.
 
In order to access the real-time correctors from ORGN, you will need a GNSS rover that is capable of receiving real-time correctors in RTCM 2.3 or RTCM 3.x format.  Both formats are non-proprietary as it is the policy of the ORGN not to send out correctors in any manufacturer proprietary format; however, we do provide correctors in the Trimble CMR+ format.
 
Each Rover Account will be issued an NTRIP user name and password for authentification which allows the rover to log onto the ORGN server that streams real-time correctors.  NTRIP is an acronym for "Networked Transport of RTCM via Internet Protocol" and is an application-level protocol for streaming Global Navigation Satellite System (GNSS) data over the Internet.  NTRIP is a generic, stateless protocol based on the Hypertext Transfer Protocol (HTTP).
  
You must also have a cellular modem or data-capable cell phone that is connected to your rover and you must purchase a data service plan from a cellular provider.  Both CDMA (example: Verizon, Sprint) and GSM (examples: Cingular, Unicel) cellular formats are capable of accessing the ORGN server that streams RTK correctors.  You should pick a cellular provider based on which provider provides the best data service coverage in the area where you will be working most.
 
The rover user will be responsible for purchasing, configuring, and maintaining the appropriate GNSS rover, cell modem, and cellular data service.  ORGN_Support will provide general support, but cannot provide support for configuring and using specific GNSS equipment, specific cellular modems, or data service.  Please contact your GNSS equipment manufacturer or vendor for GNSS support and your cellular provider for cellular service support.  We will post support documents for specific equipment and FAQ's as they become available.

 

GNSS Data for Post-Processing

Hourly RINEX files at a 5 second data rate from each reference station are posted to this website and are made available on-line for a period of one month for users, then it will be archived off-line.  The RINEX files are available at no charge to all users, whether partners/subscribers or not.
 
If an ORGN partner is already providing RINEX files on-line for their site; i.e., the partner site is a National Geodetic Survey Coop CORS site, we will not duplicate those RINEX files on the ORGN website; however, we will provide a link to the partner's RINEX data by clicking on the station on our Station Status page or by clicking on a station on one of the clickable ORGN maps.
 
The nominal epoch rate for ORGN RINEX files if 5 seconds; however, users may request  RINEX files with a faster epoch rate on a project-by-project  basis, for example, an aerial photography project using airborne GNSS control.  Contact ORGN_Support in advance of your project if you have such a need.  Users may also request archived RINEX data that is older than one month by contacting ORGN_Support.
 
To learn more about our RINEX products, please visit the About Rinex page for more information, or proceed directly to our RINEX Data Downloads page for access to the RINEX files.