Maintenance of official time in Bosnia and Herzegovina — UTC(IMBH)
Time is one of the base units of the International System of Units (SI). The international time reference is the Coordinated Universal Time (UTC). Laboratory for time and frequency in the Institute of Metrology of Bosnia and Herzegovina (IMBIH) realizes local approximation of SI unit for time, participates in calculation of UTC and generates national time scale in Bosnia and Herzegovina — UTC(IMBH). System for generation UTC(IMBH), hardware used and the operating principle of the time transfer system are presented first. Then, the IMBIH's time scale steering algorithm is briefly described. Finally, the accuracy and stability of obtained time scale are presented.
Analysis of the Ionospheric Effect for Time Offsets per GPS Code Measurements
This paper shows the analysis results of time offsets using P1, P2 and P3 code in GPS time transfer. The r2cggtts program has been used in GNSS Time Transfer and use the P3 ionosphere free combination of P1 and P2 code measurements. We modified the r2cggtts program in order to calculate and write all kinds of time offsets P3 as well as P1 and P2. The result of the modified r2cggtts program shows that time offsets using P1 and P2 are of wide distribution comparing to time offsets using P3. In order to Figure out the error factors for wide distributions of P1 and P2, we analyze and present the relation between the elevation angle and time offsets in this paper.
Ionospheric models comparison for single-frequency GNSS positioning
Broadcast Ionospheric Correction Algorithms (ICA) are used in Global Navigation Satellite System (GNSS) single frequency receivers positioning to compute the satellite signal delay due to the propagation through ionosphere. In this paper two ionospheric models are considered: Klobuchar model used by the U.S. Global Positioning System (GPS) and NeQuick model adopted by the European Galileo system. The goal of this paper is to investigate the validity and efficiency of the examined models by analyzing their performances in single frequency GNSS receiver.