Although the Relative Global Navigation Satellite System (GNSS) positioning
technique provides high accuracy, it has several drawbacks. The scarcity of
control points, the long baselines, and using of ultra-rabid and rabid products
increased position errors. This study has designed a New MATLAB Program that
helps users automatically select suitable IGS stations related to the baseline
lengths and the azimuth between GNSS points and IGS stations. This study
presented criteria for the length of the baselines used in Egypt and an advanced
estimated accuracy before starting the project. The experimental test studies
the performance of the position accuracy related to the relation between three
factors: observation session, final, rabid, and ultra-rabid products, and the
baseline lengths. Ground control point mediates Egypt was selected as a test
point. Nine surrounding IGS stations were selected as reference stations, and
the coordinates of the tested point were calculated based on them. Baselines
between the tested point and the IGS stations were classified regarding proposal
criteria. The coordinates of the tested point were obtained in different
observation sessions (0.5, 1, 2, 4, 5, 6, 7, 7.5 h). The results indicated that
the lengths of the baseline in Egypt were classified short (less than 600 km),
medium (600–1,200 km), and long (greater than 1,200 km) and required a
minimum observation time of 4, 5, and 7 h to obtain accuracy 10, 19, 48 mm
sequentially. The position accuracy was superior for the rapid and the final
than the ultra-rapid products by 16%. A short baseline was at the best case;
there was a performance in position accuracy with a 57% deduction in observation
time compared with the long baseline.