Development of GNSS Receiver for Mobile CORS with RTK Correction Services Using Cloud Server

Abstract

Requirements for precise Real Time Kinematic (RTK) positioning have been significantly growing in Indonesia since early 2010, resulting from the national programs on village mapping, land cadastre certification, infrastructure developments, and one map policy. The activities require a sub-decimetre level of positioning accuracy to produce detail maps to the scale of 1:500. RTK positioning with CORS should be the most reliable technique to meet the accuracy level. However, the existing distribution of Indonesia CORS Network, consisting of 150 active stations, is still far from adequate since the inter-station distances are of around 500 km while an ideal range should be less than 50 km. This paper related to an initiative for the development of a GNSS receiver that can be transportable and easily set up in the field as a base station to provide RTK CORS correction services with local contents. The initiative supports national efforts on the densification of Indonesia CORS Network to better distribution. The development was started using the Tersus OEM GNSS board series BX305, including the integration of the board to a mini PC. Further developments have been made covering the following, namely: i) to add a long-term stable power supply in the receiver, ii) customization of receiver command settings, iii) to add a GSM modem and internet protocol for data communication from the receiver to a cloud server, iv) installation of SNIP software in a cloud server to provide CORS corrections with NTRIP caster, and v) testing the NTRIP client performance in the rover receiver. Results from the land cadastre surveys carried out in Bandung, Padang and Tangerang Cities show that the length of time for the fixed positioning with resolved ambiguities could be obtained within less than 5-7 seconds with the rover locations less than 10 km from the base station. A longer time to obtain fixed solutions required for the distance at the range of 10 to 20 km, and it is becoming more difficult to get fixed solutions over 20 km. Further developments would be carried out using affordable price GNSS OEM boards provided by different manufacturers.