The Research Project
The CHCNAV’s i50 GNSS smart antenna and N72 GNSS reference station have been used by Turkish researchers in their study about the “Analysis of the contribution of multi-GNSS to long-distance RTK.”
The effects of baseline length on GNSS position accuracy
GNSS, as it is commonly referred to, is the acronym for Global Navigation Satellite System, which can provide users with a fast, economical and reliable positioning service with global coverage. With the introduction of the RTK technology, GNSS has become a practical tool for real-time and accurate positioning in many engineering applications. However, the accuracy of GNSS RTK measurements depends on the baseline length between the GNSS reference station and the GNSS rover. With new emerging satellite systems such as GALILEO and BEIDOU, it is possible to explore the potential impact of multi-GNSS on the long baseline RTK accuracy.
An 80 km baseline used for the GNSS RTK research project
A field trial was conducted on an 80 km baseline using different combinations of satellite constellations with the CHCNAV i50 and N72 GNSS* receivers. Researchers performed two surveys - a one-hour RTK survey and a five-hour static GNSS survey - on the rovers and reference stations respectively. Both the CHCNAV’s i50 and N72 GNSS receivers can record continuous GNSS raw data observations. With the capability to track the signal of all available GNSS systems, they were able to evaluate various satellite constellations mix. The GNSS RTCM corrections were transmitted over the NTRIP protocol (Networked Transport of RTCM via Internet Protocol) with a GSM data link. In practice, CHCNAV provides additional proprietary APIS and standard TCP protocols, using the data controller's Internet access or the internal 4G network data link of the receivers as desired.
Multi-constellations GNSS enables centimeter accuracy at long distances
The tests results demonstrated that an accuracy of +/- 5 cm horizontally and +/- 10 cm vertically can be achieved. Moreover, under open sky conditions, with sufficient numbers of satellites in view, the different mix of GNSS configurations gave almost identical results.
The paper was published on the Intercontinental Geoinformation Days (IGD) in November 2020 and is available for download at https://zcu.io/zgHD