Self-made RTK correction with RTCM data

What is RTCM correction data?

RTCM SC-104 is a standard that defines the data structure for differential correction information for a variety of differential correction applications. It was developed by the Radio Technical Commission for Maritime Services (RTCM) and has become an industry standard for communication of correction information.
 

How do I get data from RTCM?

Setup SNIP to log RTCM data



Use the username and password which you have received from the provider. Connect to the correct mountpoint. If the mountpoint is unknown or more than one option is possible, you can hit the button “Get Mount Points” to receive a list of all active ones for this station.

How does RTK correction work?

Quote from video: It computes its location also using the gnss. And computes the error in this measurement by comparing it to its precise. Location. These errors are transmitted in real time to the rover.

Do you need a base station for RTK?

It is possible to get live RTK data over NTRIP without a base station of any kind by using an internet-connected NTRIP stream. This process requires an internet connection on the job site either through local Wi-Fi, a Wi-Fi hotspot, or a dedicated 4G attachment to the controller.
 

How does RTCM work?

Technically, RTCM is just a protocol. We, however, will be using the term RTCM to mean the bytes of correction data related to GPS timing anomalies. The contents of RTCM frames can be decoded but you, the user, rarely need to. Instead you simply pass the bytes to the GPS receiver and it will parse the correction data.

What is the difference between RTK float and RTK fixed?

Comparisons of the repeated data points show that RTK fixed solutions have the best repeatability (accuracy better than one decimeter). RTK float solutions can be as repeatable as fixed solutions, but can also be out by up to five meters, with no way to tell unless surveying a known point.

How do I connect my GPS to my RTK?

RTK Connection Process



The RTK GPS connection is essentially plug and play: Start QGroundControl and attach the base RTK GPS via USB to the ground station. The device is recognized automatically. Start the vehicle and make sure it is connected to QGroundControl.

How many satellites do you need with RTK?

For RTK initialization, 5 satellites are required. This is no problem if the whole sky is visible, and, as already shown, dual frequency GPS-only RTK performance is similar to single-frequency GG-RTK when the whole sky is visible.

How is RTK calculated?

At a very basic conceptual level, the range is calculated by determining the number of carrier cycles between the satellite and the rover station, then multiplying this number by the carrier wavelength.

What does the acronym RTCM stand for?

The Radio Technical Commission for Maritime Services (RTCM) is a non-profit international standards organization. Although started in 1947 as a U.S. government advisory committee, RTCM is now an independent organization supported by its member organizations from all over the world.

What are RTCM messages?

RTCM Type 1 messages contain pseudorange correction data for GPS satellites. They are used in both the VERIPOS Standard and Standard+ calculations. RTCM Type 31 messages contain pseudorange correction data for GLONASS satellites. They are used in both the VERIPOS Standard GLONASS and GLONASS Only calculations.

What is RTK data?

RTK stands for Real-Time Kinematic and is a technique that uses carrier-based ranging and provides ranges (and therefore positions) that are orders of magnitude more precise than those available through code-based positioning.