GNSS Surveying
The Global Navigation Satellite System (GNSS) refers to a constellation of satellites providing signals from space that transmit positioning and timing data to GNSS receivers.
GNSS include Europe’s Galileo, the USA’s NAVSTAR Global Positioning System (GPS), Russia’s Global'naya Navigatsionnaya Sputnikovaya Sistema (GLONASS) and China’s BeiDou Navigation Satellite System.
The performance of GNSS is assessed using four criteria:
- Accuracy: the difference between a receiver’s measured and real position, speed or time;
- Integrity: a system’s capacity to provide a threshold of confidence and, in the event of an anomaly in the positioning data, an alarm;
- Continuity: a system’s ability to function without interruption;
- Availability: the percentage of time a signal fulfils the above accuracy, integrity and continuity criteria.
For the purpose of airborne LiDAR mapping project, all the ground control points will be established using Trimble Geodetic GNSS products. This equipment were design by Trimble for high precision multiple correlate L1 and L2 pseudo range measurements.
TAC provides the most accurate Airborne LiDAR data in Malaysia as the ground control points established using high-end technology from Trimble products.
