Handbook of Propagation Effects for Vehicular and ... - Courses

Investigations from Different Countries 7-17
acquired employing a helicopter as the transmitter platform. In Figure 7-21 through
Figure 7-24 are given similar type distributions acquired at L-Band (1.5 GHz) [Goldhirsh
and Vogel, 1989; 1995]. In Figure 7-21, the MARECS B-2 geostationary satellite was
used as the transmitter platform (elevation = 21°), whereas the other figures were derived
from measurements using the helicopter transmitter platform. The legend information in
these figures has the following significance. The “star” curve in Figure 7-18 is denoted
by 295 S, RL, HR. These symbols represent the case in which the sampled route was 295
south (295 S), the vehicle was traveling in the right lane (RL), and the helicopter was to
the right of the driver (HR). The legend information for the other curves has analogous
definitions. The solid curve showing no data points in each of these figures corresponds
to the EERS model, which is approximately representative of the median of the measured
distributions. The variability of the measured distributions is noted to generally be within
± 5 dB vis-à-vis the EERS model.
Percentage of Distance Fade > Abscissa
100
9
8
7
6
5
4
3
2
10
9
8
7
6
5
1
4
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2
Legend
295 S,RL,HR
295 N, RL, HR
295 S, LL, HR
295 N, LL, HR
108 SW, HL
108 NE, HL
32 N, HL
32 S, HL
EERS Predicted
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Fade (dB)
Figure 7-18: Cumulative distributions at UHF (870 MHz) for elevation angle = 30° from
mobile measurements made with a helicopter transmitter platform along eight roads in
central Maryland [Goldhirsh and Vogel, 1989]. Solid curve is EERS prediction.