LatPos

LatPos a Global Navigation Satellite System Continuously Operating Network of Latvia
LatPos system includes continuously operated 25 GNSS base stations evenly distributed in territory of Latvia. Average distance between stations is 70 km. Data processing center located in Riga. Data from GNSS each receiver every second has been sent to data processing center. All data are processed and distributed with different message types to users









Each reference station contains a receiver capable of receiving a signal transmitted by NAVSTAR (NAVigationSystem with Timing and Ranging – the GPS system of the U.S. Department of Defense) on L1, L2  and L5 frequencies. In the future, it is expected that signals will also be received from GLONASS (GLObal’nayaNAvigatsionnaya Sistema Svyazi – the satellite navigation system of the Russian Ministry of Defence, which is analogous to the U.S. GPS system) and GALILEO (the European GNSS system)

A GNSS reference station makes it possible for a user’s GNSS receiver to establish co-ordinates with the accuracy of two centimetres in real time and with the accuracy of five millimetres if stored data are used. Data over a longer period are also available for scientific purposes

The stations have been equipped with geodetic choke ring antennas with a dome above them,which reduce the multi-path effect of the reflected signal that may interfere with the accuracy of the measurements. All antennas have been positioned to have maximum exposure towards the sky, enabling them to receive signals from all possible satellites

Antenna of LatPos


The co-ordinates of the GNSS reference stations have been calculated in the Latvian co-ordinate system, LKS-92 TM, and linked up with the State Geodetic Network

The receivers installed at the reference stations have been placed in lockable metal compartments to prevent unauthorised access. Each receiver is connected both to a computer and to the power grid. A power supply module with built-inautonomous power supply ensures uninterrupted operation of the receiver for 48 hours. This allows surveyors to receive post-processed data under any circumstances

Equipment of LatPos station


Built-in memory allows data to be stored up to seven days. In the case of interruptions in the computer network, data are stored within the receiver and,as soon as the connection resumes, they are downloaded to the central server of the LatPos system.Each station receives satellite signals and stores the received information in hour-long files. The data frequency within the files is one second. Files with one-second frequency are stored for two months. Files with five and 30-second intervals are stored for a longer period

Two types of LatPos GNSS network data are available:
  • real-time data (transmitted immediately to the user’s GNSS receiver)
  •  post-processed data in files that can be used for calculating precise co-ordinates using geodetic software
You may apply to receive real-time data via e-mail: latpos[at]lgia.gov.lv      
Satellite data stored by the LatPos GNSS network for post-processing are available online. The data are available in RINEX format, supported by all manufacturers of GNSS systems. Registration is required in order to receive the data



Changed: 2016.03.07. 15:00


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