Multipath Measurement System (MMS) A System to detect Multipath Effects and the causing Reflectors

Dierk Hickmann

Abstract:	Electromagnetic waves travel through the atmosphere with the speed of light. In addition to the direct connection between the transmitter and the receiver there is very often a connection through reflected waves, called multipath. Because of the additional detour path, the reflected signal hits the receiver delayed in comparison to the direct signal and can interfere the receivers function. These disturbances can cause malfunctions in radio based equipment, for example navigation aids on airports or harbours. The Multipath Measurement System registers the time delay between the direct signal and the reflection and uses this data to calculate the detour length of the reflected signal. Additionaly it marks potential reflectors (e.g. fences, buildings) on a digitized map. With the Multipath Measurement System it is for example possible to find out the areas on an airport‘s runways, taxiways and aprons which are influenced by multipath effects. The number of the reflections can be shown for any measured location. Various kinds of screens and zoom functions give the advanced user the possibility to analyse the situation in more detail. Therefore it is for example possible to view the strength of the single reflections in a measurement position and to mark the causing reflectors. With the Multipath Measurement System it is also possible, to examine the installation sites of planned ground components of radio equipment on an airport (for example DGNSS reference stations or pseudolites) for multipath effects. If an already installed radio device is influenced by mutlipath effects, it is possible to find alternative locations for the antennas which might be less effected.
Published in:	Proceedings of the 11th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1998) September 15 - 18, 1998 Nashville, TN
Pages:	1075 - 1082
Cite this article:	Hickmann, Dierk, "Multipath Measurement System (MMS) A System to detect Multipath Effects and the causing Reflectors," Proceedings of the 11th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1998), Nashville, TN, September 1998, pp. 1075-1082.
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