Unmanned Aircraft Systems (UAS), i.e. drones, have been commercially
successful in both the consumer and industrial sectors in part due to the wide
variety of applications they benefit. In environmental monitoring and precision
agriculture, UASs can be utilized for data collection from rural IoT sensor
networks. These networks frequently operate over some variant of the IEEE
802.15.4 standard, taking advantage of the standard’s low power usage.
Consumer 802.15.4 radios are widely available in compact form factors, making
them ideal for application in environmental and agricultural sensor networks.
Unlike other wireless standards, 802.15.4 is well studied on the ground but has
not received rigorous evaluation in three dimensional aerial communication,
which introduces new challenges, such as antenna radiation patterns and extreme
ranges. This paper provides an initial look at the performance of 2.4GHz
802.15.4 for data collection from a UAS. We provide experimental performance
measurements using an outdoor aerial testbed, examining how factors, such as
antenna orientation, altitude, antenna placement, and obstruction affect signal
strength and reception rate of packets. We find that these parameters play a
significant role in reception rate, but have a much weaker impact on received
signal strength. We conclude by discussing some takeaways on sensor network
configuration for aerial data collection.