Continuously Operating Reference Stations (CORS): The reference stations are equipped with GNSS receivers and Choke-ring antennas to collect GNSS raw data (Carrier Phase and Pseudorange Code) at a sample rate of 5 sec (Static) and 1 sec (RTK).
Uninterruptible Power Supply (UPS) are installed at each of the CORS to ensure the GNSS receivers can work continuously even with power failure. The routers will transfer the GNSS data, meteorological observation and tilt data to the SatRef Data Centre via 64k data link. The backup GSM modems can take up the data transfer in case the network transmission failed.
SatRef Data Centre: The Reference Station Management Server set, Database & Positioning Server set and Web Server set in the Data Centre shares the main functions of SatRef. The Reference Station Management Server can remotely control the operation of CORS and collect the raw observations from the GNSS receivers, meteorological sensors and tilt sensors. The Database & Positioning Server set will process the GNSS observations and generate the correctional data for real-time positioning services. The Web Server set is used for the delivery of real-time correction messages generated via internet. It also provides a web-based interface for automatic data computation and GNSS data downloading service. Each set of servers contains 2 set of hardware for high availability to keep the system operating continuously.
Firewall and Intrusion Detection Services (IDS) are used to protect the SatRef system from being attacked by hackers.
SatRef Control Centre: The Control Centre is set up at the Office of Geodetic Survey Section, Lands Department. The system operators at the Control Room will continuously monitor the operation of the whole SatRef system using remote connections. The monitoring includes the power management, data transfer, real-time baseline checking, differential correction performance and high-precision baseline solutions of the system. The Bernese Software will perform high-precision post-processing of the GNSS data using precise orbit obtained from the International GNSS Services (IGS). The processed data could help operators to monitor the quality of the raw data. Both the Data Centre and the Control Centre will have backup facilities to allow fast recovery of service and data loss due to accidents.
Video - SatRef Control Centre: Download this video (WMV, Cantonese Only: 5.72MB)