The Bad Elf GNSS Surveyor uses an RTCM 2.3Radio Technical Commission for Maritime feed delivered through an NTRIP client from a reference station to differentially correct the GPS signal and improve the positional accuracy reported. Using the built-in NTRIPNetworked Transport via Internet Protocol client in the Bad Elf iOS application, one can connect directly to a reference station network. This write up outlines the configuration of a typical NTRIP connection.
DGPS is a technique to improve the location accuracy of the Global Positioning System. DGPS uses a network of fixed, ground-based reference stations to broadcast the difference between the positions indicated by the GPS satellite systems and the known fixed positions.
Note: The GNSS Surveyor only supports corrections of the coarse-acquisition (C/A) code (broadcast in the L1 signal)
Note: Accuracy of DGPS decreases with distance from the reference station. If the user and the station are unable to see the same satellites, this problem is further exacerbated.
Note: Where the GNSS Surveyor is configured to use differential correction data (e.g. via an RTCM stream), the receiver's coordinate frame will switch to whatever frame the source of correction data is using. For example, if the reference station is using NAD83 (2011) the locations provided by the GNSS Surveyor will shift to that datum.
The following steps demonstrate the typical steps one would use to configure the NTRIP client.