Autonomous airborne wildlife tracking using radio signal strength

Abstract

In wildlife radio tagging, small radio transmitters attached to animals are located by human operators using directional antennas and analog receivers which provide audio output. The location of the transmitter is determined by listening to the signal and scanning the area while closing in. This procedure can be very tedious, especially in rough terrain. Searching radio tags with autonomous unmanned aerial vehicles (UAVs) offers a number of advantages, including better line-of-sight signal reception, terrain-independence and faster localization. In this paper we continue upon previous work by presenting a received-signal-strength (RSS) sensor implementation based on a modified commercial wildlife tracking receiver that is designed to operate on an autonomous fixed-wing UAV. Furthermore, an extension of the search and tracking framework for multiple targets that are undistinguishable from the sensors' point of view is proposed. After a brief system overview and a summary of the particle filter based approach, the signal processing theory and realization of the RSS sensor are outlined, including strategies for frequency tracking and receiver gain control. The paper also presents experimental results.

Online Localization of Radio-Tagged Wildlife with an Autonomous Aerial Robot System

“…Although a full rotation is needed, the resulting high-quality bearing estimate allows for better localisation accuracy than has been achieved with directional antennas offline in similar applications [16]. We also found that our system achieved a detection range that is similar to hand-held systems due to the elevation of the UAV.…”

“…Wagle and Frew [29] propose a Gaussian process-based method and show experimental results from data collected by a fixed-wing UAV. Korner et al [16] report on offline estimation experiments using a directional antenna and a deterministic range-bearing sensor model. Soriano et al [26] propose a UAV system for tracking eagles that uses particle filter estimation evaluated using a ground-based testbed.…”

“…Popular loop aerials [12,28] are known to be inefficient, especially for low frequency signals. Standard horizontally-mounted directional antennas [16,22] are affected by unmanned aerial vehicle (UAV) rotors which cause unpredictable irradiance.…”

Wildlife research and management methods in the 21st century: Where do unmanned aircraft fit in?

“…Initial work focused on developing the technique's conceptual and mathematical framework, along with computer simulations and limited ground-based testing without animals (Posch and Sukkarieh 2009;Soriano et al 2009;Korner et al 2010). Other efforts have focused specifically on the case of tracking radio-tagged fish Leonardo et al 2013;Jensen et al 2014), including mathematical modeling, computer simulations, the design of a UAS-borne telemetry tracking payload and live flight tests (without real animals).…”

Bat flight analysis around wind turbines : a feasibility study

“…Studying bat behaviour therefore should be done at three different spatial scales: on the scale of an larger scale (Lagerveld et al in prep, Francis et al 2016, Janssen et al 2016, Kays et al 2011, Körner et al 2010, Rerucha et al 2014, Sjöberg et al 2015, Smolinsky et al 2013 3) Can reliable estimates be obtained of the number of bats which pass through offshore wind farms and over the southern North Sea in general, when behavioural data is combined with bat detector data?…”