RTK land measurement uses an external GNSS receiver and correction data. Dipper displays its fix status and accuracy estimate on iPhone, iPad and Android. These help assess each point; an RTK fixed solution alone does not guarantee accuracy.
1. An RTK GNSS receiver
An external receiver with RTK, connected to the phone over Bluetooth LE or Wi-Fi. See Choosing a GNSS receiver and Connect a GNSS receiver.
Multi-band RTK can help in difficult conditions. Check the model’s specifications; it does not guarantee a fixed time to initialize.
2. An NTRIP correction account
For single-base RTK, a shorter baseline generally helps. There is no universal distance limit; check the receiver specifications and the correction service’s coverage. Network RTK can work differently.
- A government or university network (CORS). Many countries, states and provinces run one, often free after registration.
- A commercial RTK service, by monthly or yearly subscription, usually with wider coverage.
- Your own base station, or a community caster nearby.
The service gives you a caster address, port, username and password to enter in the app. See Set up RTK corrections (NTRIP).
3. Internet on the phone while you measure
The app receives the corrections over the phone's internet connection, mobile data or Wi-Fi, and passes them on to the receiver. They have to keep arriving for as long as you measure: when they stop, the receiver soon drops back from centimeter level. In the field that usually means mobile data with coverage where you work.
The phone's internet isn't needed if the receiver gets corrections by itself, for example over radio from your own base station, or through its own SIM card.
Then wait for the fix
Time to RTK fixed varies with the receiver, baseline, satellite visibility, multipath and correction data. Wait for a stable solution and check its accuracy estimate.
Fix levels and accuracy · Why isn't RTK fixing?