Accuracy of Lightweight Satellite Telemetry: A Case Study in the Iberian Peninsula

Abstract

Here we provide the first assessment of the accuracy of lightweight satellite transmitters (,80 g) under actual operating conditions and the performance of the Argos system in southern Europe. To estimate transmitter accuracy we used transmitters equipped with a Global Positioning System (GPS) and compared the location estimates provided by Argos with the estimates provided by the GPS. Using the 68th percentile to define the accuracy of locations estimates, observed accuracy was 4 km for Location Class (LC) 1, 15 km for LC 0, 20 km for LC A, and 59 km for LC B, which is in line with estimates reported by other authors. Yet, the error of the remaining 32% of the data ranged between 4 km and 11 km, 15 km and 217 km, 20 km and 145 km, and 59 km and 493 km, respectively, suggesting that using the 68th percentile to estimate accuracies might give misleading confidence on the accuracy of location estimates. Using the 90th percentile is probably more appropriate. Less than 10% of the locations we obtained corresponded to the more accurate LCs (3, 2, and 1), with Argos failing to provide a position estimate in 45% of the attempts. The low number of high-quality location estimates is likely a consequence of the electromagnetic interference reported for our study area, rather than a defect of the Platform Transmitter Terminals (PTTs), which under good conditions of signal reception seem to be as reliable as heavier ones. The recent advent of lightweight GPS transmitters overrides most of these problems. Yet, whereas the smallest Argos-GPS PTTs weigh 30 g, which restricts their use to animals weighting .1,000 g, conventional PTTs can be as small as 9.5 g, allowing their use with animals weighting

Attachment and performance of Argos satellite tracking devices fitted to black cockatoos (Calyptorhynchus spp.)

“…The accuracy of the location fixes provided by the tracking devices exceeded expectations based on previously published studies using Argos systems (Britten et al 1999;Soutullo et al 2007;Dubinin et al 2010), where it is common for the lower accuracy classes to dominate results and for the accuracy of location classes to not be as great as that reported by Argos (Meyburg and Fuller 2007;Douglas et al 2012;Boyd and Brightsmith 2013). There are several factors that may explain the better performance of the Argos tracking devices during the present study.…”

The Spring Migration of Adult North American Ospreys

“…All the Doppler-based satellite telemetry units (ARGOS PTTs) were programmed to transmit data for an 8-or 10-hr period followed by a 20-72-hr off period. Accuracy of ARGOS provided location estimate depends on a variety of factors which have been commented on by other researchers (see Keating et al 1991, Britten et al 1999, Vincent et al 2002, Soutullo et al 2007). …”

Global positioning system and associated technologies in animal behaviour and ecological research

“…This increases data transfer and power efficiency for the system. When GPS transfer via Argos is applied to birds, solar charging often is used to prolong unit operation life (Soutullo et al 2007). …”