Take ZebraNet sensor nodes [28] as an example. On average,
one GPS location fix requires turning on the GPS chip
for 25 seconds at 462mW power consumption, which dominates
its energy budget. As a result, the unit is equipped with
a 540-gram (1.2 pound) solar cell array and a 287-gram (0.6
pound) 2A-h lithium-ion battery in order to support one GPS
position reading every 3 minutes. Power generation and storage
accounts for over 70% of the sensor unit’s total weight
of 1151 grams (2.5 pounds).