Advancing Vietnam's Geodetic Infrastructure with Nationwide GNSS Reference Networks

Spanning 1,650 kilometres from north to south, Vietnam presents a varied landscape of forested mountains, fertile river deltas, extensive coastline, and rapidly developing urban areas. Ensuring Vietnam’s geodetic infrastructure is modern and reliable is crucial for national surveying and mapping activities based on GNSS technologies. 

However, the impact of a strong infrastructure extends further: when GNSS positioning data is accurate and easily accessible, it supports a range of other applications, from infrastructure development to environmental monitoring, atmospheric research, and much more. Today’s extensive Continuously Operating Reference Station (CORS) in Vietnam, comprised of Leica Geosystems technologies, make all this possible with centimetre-level, real-time and post-processing positioning data available across the country. 

Transforming Vietnam’s national mapping with GNSS reference station networks

In 2016, the Department of Survey, Mapping and Geoinformation Viet Nam (DOSMVN), the nation’s geospatial data authority, embarked on an ambitious project to construct a GNSS network throughout the country. To achieve these goals, the DOSMVN needed to establish CORS at a national scale, comprised of a combination of GNSS receivers and antennas and sophisticated software to continuously log, process, and provide accurate positioning data in real-time. 

This initiative would overhaul Vietnam's geodetic infrastructure, leveraging the advanced capabilities of real-time GNSS positioning technology to refine surveying and mapping processes and enhance the national coordinate and projection system. 

"The deployment of the CORS network across Vietnam was an important step towards harnessing the full spectrum of GNSS data for our national mapping efforts,” explains Tran Phuc Thang, Director of the Centre for Investigation – Processing of Survey and Mapping Data at the DOSMVN. 

“The network connects satellite positioning stations nationwide into a unified system to optimise equipment, minimise investment, and expand operational capabilities for various applications,” continues Thang. “It ensures compliance with the International GNSS Service (IGS) network and networks of other GNSS organisations worldwide.”

 

National GNSS network benefits industry and infrastructure development

This project showcases the evolution from traditional methods to the latest solutions and exemplifies the benefits of adopting a nationwide GNSS reference network for advancing surveying and mapping along with a range of other industry applications.

“In addition to modernising our mapping, we wanted to achieve high precision in Real-Time Kinematic Positioning (RTK) and Network RTK services applicable across various industries," says Thang. 

Many industries across Vietnam depend on accurate geospatial data to use advanced technologies and to ensure project data is complete. This ranges from survey work, like using GNSS rovers to measure property boundaries or drones to take aerial surveys of construction sites, to autonomous machine control applications, infrastructure development, and more.  

Providing easily accessible 24/7 network RTK corrections to companies across Vietnam presents several economic and infrastructure development benefits. Continually and widely available RTK data reduces cost incurred by businesses that would otherwise have much higher cost of operations without such service available. This leads to cost savings in sectors such as civil engineering, construction, agriculture, and transport - helping spur economic growth.

Additionally, reducing the cost of acquiring high-precision spatial data helps the planning and accurate execution of large-scale infrastructure projects important to adapting to Vietnam’s growing urban populations. 

Scientific research and environmental monitoring with GNSS

Researchers in areas such as environmental science, geology, and cartography also benefit, as they can carry out more extensive and accurate studies. The CORS in Vietnam has notably improved the ability to measure array displacement speeds and contributed valuable data for meteorological and ionospheric research.

CORS provide a way to measure ionospheric levels, using receivers to collect information about the ionospheric delay GNSS signals experience along their path. This allows experts to calculate the total electron count (TEC) and map ionospheric electron density. Ionospheric activity directly affects the accuracy of GNSS-based systems for surveying, navigation, telecommunications, and more. Monitoring the ionosphere enables experts to assess the reliability of these systems and take mitigation measures when possible.

The network also provides valuable information about atmospheric conditions, including the amount of water vapour in the atmosphere – especially significant for the high rainfall areas in Vietnam. Similar to measuring ionospheric activity, CORS receivers record the delay GNSS signals experience when travelling through the atmosphere due to water vapour. By comparing the estimated and actual arrival times of GNSS signals at CORS receivers, it is possible to estimate the water vapour levels. This method provides unique meteorological observations, which contribute to weather forecasting and climate studies.

Additionally, Vietnam’s extensive network makes it possible to monitor movements in the earth’s crust and the speed of these movements over time with GNSS. As a seismically active region, this is an especially valuable resource for recording and predicting ground movements.