1. LATVIA POSITIONING SYSTEM BASE STATION INSTALLATION IN VALKA “Geoforum 2015“ April 22-24 Armands Celms Aivars Ratkevičs Elita Eglāja Latvia University of Agriculture 1

2. EUPOS - RIGA Fig.1.EUPOS – Riga base stations locations in Riga, Latvia 2

3. Trimble VRS now TEC Fig.2.Trimble VRS now TEC network base stations locations in Latvia 3

4. LatPos - a Global Navigation Satellite System Continuously Operating Network of Latvia Fig.3. LatPos base station locations in Latvia 4

5. Fig.4. Baselines to the nearest base stations, forming triangles 5

6. LatPos BASE STATION INSTALLATION IN VALKA 6

7. Palsmane – 43 kilometers Valmiera – 44 kilometers The nearest base stations Fig.5. The nearest base stations to Valka 7

8. Control measurements in Real Time (RTK) National geodetic points (Class 1) – Burga – Tilikas – Kalki National geodetic points (Class 2) – 4009 – 40114016 Fig.6. National geodetic point – Class 1 - Tilikas 8

9. Fig.7. Surveyed the National Geodetic Network coordinate linear difference 9

10. Conclusions Present situation  Valka is located in the border zone, ther by the LatPos signal is to weak for geodetic measurements.  The average fixation time 2-4 minutes,  The average Root Mean Square accuracy ( RMS) 4 – 9 cm. 10

11. Expected results in Valka and its neighbourhood: Fixation time to 30 seconds; measurement accuracy of 2 centimetres; a good cooperation in the field of geodesy with neighbour country - Estonia. 11

12. 12 THANK YOU FOR YOUR ATTENTION !