The article presents the results of an experiment aimed at investigating the influence of the horizon cutoff angle (mask angle) on the accuracy of GPS determinations. This issue has already been addressed in publications concerning satellite navigation; however, increasingly accurate ionospheric and tropospheric models justify, in the author’s opinion, conducting periodic research in this area. The mask angle is set by the GPS receiver operator, so it is worth considering what its value should be. This article is a contribution to the discussion, and the presented experimental results seem to challenge the generally prevailing opinions in this regard.The horizon cutoff angle (mask angle) allows the user of a satellite navigation system receiver to determine the minimum topocentric elevation of satellites to be used in the process of determining position coordinates. Satellites whose elevation above the horizon plane is less than the entered mask angle value are ignored by the receiver – pseudorange measurements made to them are not included in the system of observation equations. It is believed that a single-frequency pseudorange measurement performed using the code method to a satellite with a low topocentric elevation is subject to a greater error, resulting from ionospheric and tropospheric refraction, than to a satellite located higher. Hence the idea of introducing a mask angle in the receiver. (…)
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Source: Logistyka Magazine