Assessing the accuracy of small satellite transmitters on free‐living flying‐foxes

McKeown, Adam; Westcott, David A.

doi:10.1111/j.1442-9993.2011.02276.x

Cited by 11 publications

(10 citation statements)

References 36 publications

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“…First, camps are never dropped from our monitoring, even when they haven’t been occupied for long periods, so there is no shift of monitoring to an urban focus that might result from easier sampling. Second because non-urban camps are more likely to be overlooked than urban camps, we would expect an initial bias towards urban camps that would decrease as the population became better known through broad-scale searches, reports from the public [22] and telemetry studies [36] , [50] . Instead we have seen the shift towards urban camps increase.…”

Section: Discussionmentioning

confidence: 99%

Are Flying-Foxes Coming to Town? Urbanisation of the Spectacled Flying-Fox (Pteropus conspicillatus) in Australia

et al. 2014

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Urbanisation of wildlife populations is a process with significant conservation and management implications. While urban areas can provide habitat for wildlife, some urbanised species eventually come into conflict with humans. Understanding the process and drivers of wildlife urbanisation is fundamental to developing effective management responses to this phenomenon. In Australia, flying-foxes (Pteropodidae) are a common feature of urban environments, sometimes roosting in groups of tens of thousands of individuals. Flying-foxes appear to be becoming increasingly urbanised and are coming into increased contact and conflict with humans. Flying-fox management is now a highly contentious issue. In this study we used monitoring data collected over a 15 year period (1998–2012) to examine the spatial and temporal patterns of association of spectacled flying-fox (Pteropus conspicillatus) roost sites (camps) with urban areas. We asked whether spectacled flying-foxes are becoming more urbanised and test the hypothesis that such changes are associated with anthropogenic changes to landscape structure. Our results indicate that spectacled flying-foxes were more likely to roost near humans than might be expected by chance, that over the period of the study the proportion of the flying-foxes in urban-associated camps increased, as did the number of urban camps. Increased urbanisation of spectacled flying-foxes was not related to changes in landscape structure or to the encroachment of urban areas on camps. Overall, camps tended to be found in areas that were more fragmented, closer to human habitation and with more urban land cover than the surrounding landscape. This suggests that urbanisation is a behavioural response rather than driven by habitat loss.

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Section: Discussionmentioning

confidence: 99%

Are Flying-Foxes Coming to Town? Urbanisation of the Spectacled Flying-Fox (Pteropus conspicillatus) in Australia

et al. 2014

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“…The realism of Argos-quoted location errors has been the subject of substantial investigation (e.g., [16], [17], [18], [20], [21], [22], [23]). Uniformly, these papers have reported that the 1-dimensional error estimates provided by Argos greatly underestimate the observed errors using a variety of different PTTs at different sites.…”

Section: Introductionmentioning

confidence: 99%

Error Properties of Argos Satellite Telemetry Locations Using Least Squares and Kalman Filtering

Boyd

Brightsmith

2013

PLoS ONE

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Study of animal movements is key for understanding their ecology and facilitating their conservation. The Argos satellite system is a valuable tool for tracking species which move long distances, inhabit remote areas, and are otherwise difficult to track with traditional VHF telemetry and are not suitable for GPS systems. Previous research has raised doubts about the magnitude of position errors quoted by the satellite service provider CLS. In addition, no peer-reviewed publications have evaluated the usefulness of the CLS supplied error ellipses nor the accuracy of the new Kalman filtering (KF) processing method. Using transmitters hung from towers and trees in southeastern Peru, we show the Argos error ellipses generally contain <25% of the true locations and therefore do not adequately describe the true location errors. We also find that KF processing does not significantly increase location accuracy. The errors for both LS and KF processing methods were found to be lognormally distributed, which has important repercussions for error calculation, statistical analysis, and data interpretation. In brief, “good” positions (location codes 3, 2, 1, A) are accurate to about 2 km, while 0 and B locations are accurate to about 5–10 km. However, due to the lognormal distribution of the errors, larger outliers are to be expected in all location codes and need to be accounted for in the user’s data processing. We evaluate five different empirical error estimates and find that 68% lognormal error ellipses provided the most useful error estimates. Longitude errors are larger than latitude errors by a factor of 2 to 3, supporting the use of elliptical error ellipses. Numerous studies over the past 15 years have also found fault with the CLS-claimed error estimates yet CLS has failed to correct their misleading information. We hope this will be reversed in the near future.

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“…Available technologies, such as Platform Terminal Transmitter (PTT) and GPS tags [18], cannot hope to achieve these goals because their power demands conspire to make the tags useful for only single aspects of the study described above. That is, they can either collect a handful of daytime fixes at regular intervals over long-periods, or they can collect high-frequency movement data over short periods.…”

Section: Motivating Applicationmentioning

confidence: 99%

Camazotz

Jurdak

Sommer

Kusý

et al. 2013

Proceedings of the 12th International Conference on Information Processing in Sensor Networks

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Long-term outdoor localisation with battery-powered devices remains an unsolved challenge, mainly due to the high energy consumption of GPS modules. The use of inertial sensors and short-range radio can reduce reliance on GPS to prolong the operational lifetime of tracking devices, but they only provide coarse-grained control over GPS activity. In this paper, we introduce our feature-rich lightweight Camazotz platform as an enabler of Multimodal Activity-based Localisation (MAL), which detects activities of interest by combining multiple sensor streams for fine-grained control of GPS sampling times. Using the case study of long-term flying fox tracking, we characterise the tracking, connectivity, energy, and activity recognition performance of our module under both static and 3-D mobile scenarios. We use Camazotz to collect empirical flying fox data and illustrate the utility of individual and composite sensor modalities in classifying activity. We evaluate MAL for flying foxes through simulations based on retrospective empirical data. The results show that multimodal activity-based localisation reduces the power consumption over periodic GPS and single sensor-triggered GPS by up to 77% and 14% respectively, and provides a richer event type dissociation for fine-grained control of GPS sampling.

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Assessing the accuracy of small satellite transmitters on free‐living flying‐foxes

Cited by 11 publications

References 36 publications

Are Flying-Foxes Coming to Town? Urbanisation of the Spectacled Flying-Fox (Pteropus conspicillatus) in Australia

Are Flying-Foxes Coming to Town? Urbanisation of the Spectacled Flying-Fox (Pteropus conspicillatus) in Australia

Error Properties of Argos Satellite Telemetry Locations Using Least Squares and Kalman Filtering

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