Ingus Mitrofanovs

Multiple Frequencies Precise GNSS RTK System Research in Dynamic Mode

Abstract High precision GNSS systems are widely used for geodetic measurement. Given research work presents the possibilities to use GNSS system with phase measurements and real time data correction to establish location of dynamic objects. Test was done by using specially equipped vehicle, which was equipped with high-precision two systems (GPS and GLONASS) phase meter Topcon GRS-1 and a realtime correction system, which used GSM GPRS data transfer format [1].

Development of the One Centimeter Accuracy Geoid Model of Latvia for GNSS Measurements

There is an urgent necessity for a highly accurate and reliable geoid model to enable prompt determination of normal height with the use of GNSS coordinate determination due to the high precision requirements in geodesy, building and high precision road construction development. Additionally, the Latvian height system is in the process of transition from BAS- 77 (Baltic Height System) to EVRS2007 system. The accuracy of the geoid model must approach the precision of about ~1 cm looking forward to the Baltic Rail and other big projects. The use of all the available and verified data sources is planned, including the use of enlarged set of GNSS/levelling data, gravimetric measurement data and, additionally, the vertical deflection measurements over the territory of Latvia. The work is going ahead stepwise. Just the issue of GNSS reference network stability is discussed. In order to achieve the ~1 cm precision geoid, it is required to have a homogeneous high precision GNSS network as a basis for ellipsoidal height determination for GNSS/levelling points. Both the LatPos and EUPOS® - Riga network have been examined in this article.

State and dynamic precision research using two GPS receivers with RTK

Given the research work presents the results of GPS systems for dynamic precision estimation, using the real time kinematic (RTK) phase measurements of position with two receivers. Receivers antennas have constant distance between them. The network of base stations EUPOS-Riga and LATPOS was used to correct errors. State estimation results are presented as well. The GPRS data exchange among correctional station and receivers was used. The results of precision estimation reveal that centimetre accuracy may be achieved using the fixed solution. Precision of state estimation (course and roll angles) depends on antennas base.

Changing the national height system and GEOID model in Latvia

AbstractAccording to the decision of IAG Reference Frame Sub-commission for Europe (EUREF) the EVRF2007 solution as the vertical reference has to be deployed in EU countries.The new height system LAS-2000,5 had been enacted as the European Vertical Reference System’s EVRF2007 realization in Latvia and the new geoid model LV’14 had been introduced by Latvian authority Latvian Geospatial Information Agency. However, the appreciation of the quality of quasi-geoid model LV’14 is rather contradictious among the users in Latvia. The independent estimate and comparison of the two Latvian geoid models developed till now has been performed by the Institute of Geodesy and Geoinformatics. Previous geoid model LV98 which was developed for Baltic-1977 height system almost 20 years ago is outdated now. Preparatory actions described in order to fulfil the task of comparison the geoids in two different height systems. The equations and transformation parameters are presented in this article for the normal height conversi...

Experimental results of attitude determination with high precision GNSS receivers

This article implies the results of attitude determination of land vehicle with high precision GNSS signal receivers. We analyze vehicle roll angle, heading and geometric centre determination possibility and precision. There are theoretical and practical results presented in the article. In aim to implement the practical part two precise GNSS receivers were installed on the roof of a vehicle. GNSS receivers use signals from GPS and GLONASS satellite systems and are supplemented with real time differential correction (RTK) from local network EUPOS-Riga. The given research has proven that it is possible to determine the road slope with accuracy 0.1 degree in static and 0.5 degree in dynamic mode.

GPS receiver with phase measuring precision estimation

Given research work presents the results of GPS systems receiver with phase measuring precision estimation in Riga, using the real time kinematic (RTK) measurements of position. the network of base stations EUPOS-Riga was used to correct errors, including five stations. The precision determination was made using the “floating solution” and “fixed solution”. The results of precision in DGPS mode are presented as well. The GPRS data exchange between correction station and receiver was used. The results of precision estimation reveal that centimetre accuracy may be achieved using the fixed solution.