Effects of environmental obstacles Consider a sensor field deployed at uniform node density,

d, which yields an intersensor spacing,

a, in a regular grid deployment. Let the area for which one sensor is responsible be denoted by A¼a2. Consider a circular obstacle of diameter, l,which blocks the coverage of the sensor. Suppose the area occluded by the obstacle is A0. Assume that the sensor is capable of limited mobility over a range that is a small multiple of l. Define the probability of missed detection as

Pmiss ¼
1 A Z A0 Z ftargetðx; yÞdx dy;
where ftarget (x, y) is the probability density of the target location within A.
Assume ftarget (x, y) to be uniform. Consider the position of the obstacle shown in Figure 12.17 is such that both the tangents from the sensor to the obstacle circle meet the top edge of the tile. Let 1 be the angle made by the tangent to the obstacle edge with the vertical line joining the sensor and the center of the obstacle. Let the distance of the obstacle center from the sensor be x.

(a) Calculate Pmiss for this scenario.

(b) If the sensor moves from the present location to 2l, what is Pmiss?

Transcribed Image Text:

x Figure 12.17 Occlusion geometry. 21