April 2012
Beginner
232 pages
5h 51m
English
Chapter 7
Human User Effects on GNSS Antennas
7.1 Interaction of Human Body and GNSS Antennas
The GNSS devices in wireless body area networks (WPANs) and wireless personal area networks (WBANs) typically operate either in on-body positions (held by the user) or in near-body positions (working in the proximity of the human body). In either case, the presence of the human body in the vicinity degrades the performance of the embedded GPS antennas of such devices.
It is now a well-established phenomenon that the human body is a very lossy medium that affects the performance of the antenna in three ways: reduction in efficiency due to electromagnetic absorption in the tissues; degradation of the radiation pattern; and variation in the feed point impedance [1–7]. Characterisation of these effects is a challenging but necessary task to provide guidelines for the design of an optimal performance antenna resilient to these degrading factors [8–11].
Following the land mobile antennas, the performance of GPS antennas also tends to deteriorate when placed near the human body [12]. It increases the magnitude of degradations in the mobile terminal GPS antennas operating in the multipath environment, that already have been suffering from reflections, diffraction and scattering of the incoming radio waves from surrounding objects [13, 14]. This results in attenuation, delay and distortion of the communication link. To guarantee a reliable navigation system that can also meet the Federal Communications ...
