GLONASS signals enabled users to obtained positioning from GNSS constellation. Receiving signals from GNSS allows users to evaluate and
control the positioning performance and data collected session. In this paper, the position performance of a baseline observed for nearly 3-hours
has a length of 205 km was assessed. Precise and broadcast ephemeris from GPS only and form GLONASS and GPS combination (GNSS) were
used. Data processing using LGO (Leica Geo Office 8.4) under different processing conditions and different session of data collection (0.5,1, 2, and
3 - hours) was done to obtain the positions of the unknown point (s2) related to the reference one (s1) for the selected baseline. Results indicate that
systematic bias exists between GNSS and GPS-only for all conditions. In the smallest time observation (0.5-hour) only GNSS ephemeris has the
capability of solving baseline ambiguity and obtain accepted position performance. A slight change in position performance within a few
millimeters noted using ephemeris from GNSS and GPS (precise and broadcast ephemeris) in the case of using the entire full observation session
(3-hours). 1- and 2-hours observations session got results very close to each other, only a few millimeter's deference indicated in 3-hour of the
observation. The paper indicates that there is no solution before half of the hour of observation session except using GNSS broadcast ephemeris for
this baseline length. Compared the solutions from GPS-only, the integration of GPS and GLONASS data can improve the 3-dimensional positions
accuracy and reduced observation to 1/6 in baselines Within 200 km length. |
