ICORN (coming 2027)

Free trial

Not published (restricted network, not open to the public)

Discounts / exemptions

Not published (restricted network, not open to the public)

What's included

Not published (restricted network, not open to the public)

Where it works

State-run network for Illinois.

Stations

Not published (restricted network, not open to the public)

Official coverage map

Open map →

Needs cell signal?

Yes: NTRIPNTRIPThe standard way RTK corrections are sent over the internet. Think of it as internet radio for correction data.Full definition needs internet at the roverRoverThe receiver that moves around the job, like a survey pole or a drone. It uses the base's corrections to find its exact spot.Full definition (cell data or a phone hotspot). General rule, not an operator statement.

Network

Station spacing 35-50 km, statewide deployment in progress

NTRIP caster

Mount types

Not published (restricted network, not open to the public)

Correction formats

RTCM 3RTCMThe common format RTK corrections are written in, so different brands can understand each other.Full definition.x via NTRIP

Satellites (constellationsConstellationOne family of navigation satellites, like GPS, GLONASS, Galileo or BeiDou. More constellations means more satellites to use.Full definition)

GPSGPSThe US satellite navigation system. People often use "GPS" to mean all satellite positioning.Full definition, GLONASS, Galileo, BeiDou, QZSS

Datum / epochEpochOne moment of GPS measurement. A receiver logging at 1 Hz records one epoch every second.Full definition / geoidGeoidA lumpy, imaginary "sea level" surface around the whole Earth. Elevations are measured from it.Full definition

Aligned with ITRFITRFInternational Terrestrial Reference Frame. A worldwide datum. In the US it's about a meter different from NAD 83.Full definition and NGSNGSNational Geodetic Survey. The part of NOAA that runs the official US coordinate system, CORS and OPUS.Full definition standards

Must send GGAGGAA short message your rover sends with its rough location. VRS and nearest-station streams need it to know where you are.Full definition position?

Not published (restricted network, not open to the public)

Accuracy

Not published (restricted network, not open to the public)

Receivers that work

Not published (restricted network, not open to the public)

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How long approval takes

Not published (restricted network, not open to the public)

Terms / user agreement

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Support

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Last checked

Oct 16, 2026