State-run network
$100
SOPAC / UC San Diego
Good to know: 1 account per organization: $100 one-time registration contribution; more access through a $1,000/yr data contribution
Where it works
1 stateState-run network for California.
All plans
| Plan | Price | Term |
|---|---|---|
| Single account | Free (1 account per organization; $100 one-time processing fee) | |
| Contributing member | $1,000/yr donation per extra NTRIPThe standard way RTK corrections are sent over the internet. Think of it as internet radio for correction data.Full definition account | Annual |
| Consortium member | $20,000/yr (any 20 sites, voting) | Annual |
| Statewide consortium | $150,000/yr (all sites) | Annual |
- Discounts / exemptions
- Universities and K-12 exempt from the fee with an institutional email
Coverage
- Where it works
- State-run network for California.
- Stations
- Not published; the public SourcetableThe list of every mount point a caster offers. Your app shows it when you connect without picking one.Full definition listed 681 mountpoints on Oct 17, 2026 (network products plus any single-station streams)
- Needs cell signal?
- Yes: NTRIP needs internet at the RoverThe 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.
Connection settings
NTRIP caster
host132.239.152.4
PortA number that tells your device which "door" on the caster server to use. For NTRIP it's often 2101.Full definition2102 (Zones 1-2), 2103 (Zones 3-4), 2104 (Zone 5), 2105 (Zone 6)
mountsDIXN_RTCM3, HCRO_RTCM3, P058_RTCM3, P134_RTCM3, P139_RTCM3, P140_RTCM3, P142_RTCM3, P143_RTCM3, P144_RTCM3, P146_RTCM3, P147_RTCM3, P149_RTCM3, P150_RTCM3, P154_RTCM3 … (681 in total)
Confirmed live: a public sourcetable request to 132.239.152.4:2102, 132.239.152.4:2103, 132.239.152.4:2104, 132.239.152.4:2105 answered on Oct 17, 2026 with 681 mountpoints.
- Mount types
- Single base (pick nearest station)
- Correction formats
- RTCMThe common format RTK corrections are written in, so different brands can understand each other.Full definition.0
- Datum / EpochOne moment of GPS measurement. A receiver logging at 1 Hz records one epoch every second.Full definition / GeoidA lumpy, imaginary "sea level" surface around the whole Earth. Elevations are measured from it.Full definition
- CSRS Epoch 2017.50 (NAD83) since Mar 1, 2018
- Must send GGAA short message your rover sends with its rough location. VRS and nearest-station streams need it to know where you are.Full definition position?
- Yes for VRSVirtual reference station. The network blends nearby stations to create a pretend base right next to you, which keeps the baseline short.Full definition / network / nearest-base mountpoints (your rover must send its position as an NMEAA common text format GPS receivers use to report position and status. GGA is one NMEA message.Full definition GGA message). General rule based on the mount types.
Sign-up steps
- Register on the CRTN form
- Pay the $100 contribution
- Email the confirmation to [email protected]
- Sign-up page
- Go to sign-up →
Fine print
- Support
- [email protected]
- Last checked
- Oct 17, 2026
Not really free: operator registration form asks for a $100 non-refundable contribution. The SOPAC site timed out.
States covered1
Not listed by the operator: free trial, what's included, a coverage map, which satellites and a few other details. Ask them before you sign up if these matter to you.
No user reliability reports yet. Used it in the field? Tell us how it went.