Research and Development of Real-time High-precision GNSS Receivers: A Feasible Application for Surveying and Mapping in Vietnam

In recent years, the Global Navigation Satellite System (GNSS) has been widely applied in surveying and mapping. Currently, in Vietnam, dual-frequency GNSS receivers are quite extensively applied with the real-time kinematic (RTK) measurement technique using a continuously operating reference station network. However, high-accuracy GNSS receivers are often expensive, sometimes not meeting the needs of users for specific applications. This research develops two types of low-cost highprecision GNSS receivers for RTK positioning for different purposes. First, the millimeter precision GNSS receiver used in real-time displacement monitoring is based on Trimble's BD970 mainboard technology and some other modules. These components are interconnected according to a standard design scheme and assembled in an enclosure to form a GNSS receiver. In addition, a GNSS data transmission in the National Marine Electronics Association standard format by Networked Transport of Radio Technical Commission for Maritime Services via Internet Protocol (NTRIP) has been designed and developed. The GNSS receiver after development is loaded with program code written in the C# programming language, using the Arduino programming tool. Second, the GNSS receivers have the centimeter accuracy for RTK positioning used in surveying and mapping based on U-blox's mainboard technology and some other modules. These modules are also connected together according to a standard design scheme and assembled in an enclosure to form a complete GNSS receiver. The evaluation results show that the designed and developed GNSS receivers completely meet the requirements of surveying and mapping in coal mines in Vietnam, such as real-time monitoring of landslides, surveying and topographical mapping and other surveying works to serve the mining process