عنوان مقاله [English]
نویسنده [English]چکیده [English]
Instantaneous application of distance corrections in the DGPS relative positioning method has led to increase of precision and validity of this method. While great errors such as atmospheric delays and unusual fluctuations in satellite clocks’ behavior and orbital information can affect relative and movable positioning by GPS, application of DGPS method and its instantaneous corrections brings about precisions of the order of one meter and less for dynamic aims. In this method, instantaneous relative positioning of still receiver with known coordinates is like a pseudo-satellite that can send waves and encoded messages similar to codes sent from satellites to moving receivers. The major advantage of this encoding is prevention of measuring a broad spectrum of waves in a distance from pseudo-satellite in frequency band of GPS wavelengths, namely around 1 to 2 GHz, which propagate in a direct line in atmosphere. Therefore, pseudo-satellite concepts can be used in applications such as aerial surveying and photogrammetry.