Antenna actuation for radio telemetry in remote sensor networks

We present a radio telemetry solution for remote sensor networks that uses rotational actuation of directional antennas. The benefits of this solution over either omnidirectional or fixed directional antennas for intra-nodal communications include greater energy efficiency, sparse node deployment, and robustness to node failure. Four strategies for minimizing link acquisition time are presented. Each strategy uses a search algorithm tailored to a unique combination of radio hardware to provide nodes with coordination and/or geolocation capabilities. These strategies are implemented on a two-node testbed and their performance is measured in a realistic field trial. Results show that the use of secondary radios for search coordination and geolocation provide an order of magnitude reduction in search duration. In particular, the strategy using only search coordination yields performance that is independent of node separation while performance of the strategy using only geolocation is strongly dependent on range.