دراسة تحليلية لصور الرادار الروسي "الماز" المأخوذة لمدينة الرياض

الملخص EN

Almaz satellite ,flown by the Russian Space Corporation in 1991, was the first Russian satellite to carry a side-looking radar onboard for commercial purposes.

One image of this satellite covering the city of Riyadh and surroundings was made available to the author for the purpose of attesting the cartographic accuracy of this new system for urban security, intelligence-gathering and related civilian mapping applications.

The image was subjected to a series of experiments ranging from simple visual interpretation to applying highly sophisticated mathematical models to transform radar image coordinates from image system to ground coordinate system.

The results showed that this Russian satellite radar system suffers from a multitude of geometric errors that seriously affected locational data-gathering.

The interpretational part of the test revealed the fact that because of the special imaging characteristics of the radar system ,many of the important information could not be discerned.

Furthermore, and because of the same reasons, a linear feature could, or could not, be identified simply because of its orientation with respect to the satellite ground track.

Taking all of this into consideration, it is concluded that information-gathering from this system is possible only at scales 1/250 000 and smaller .

Nevertheless, such information could be useful in cases when it is impossible or difficult to obtain data from other sources eg.

during persistent dust storms or heavy rainfall since radar is immune from these natural events.