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The BAARA (Biological AutomAted RAdiotracking) system: a new approach in ecological field studies.

Řeřucha Š, Bartonička T, Jedlička P, Čížek M, Hlouša O, Lučan R, Horáček I - PLoS ONE (2015)

Bottom Line: This new approach to a tracking system was tested for its applicability in a series of field and laboratory tests.BAARA has been tested within fieldwork explorations of Rousettus aegyptiacus during field trips to Dakhla oasis in Egypt.The results illustrate the novel perspective which automated radiotracking opens for the study of spatial behaviour, particularly in addressing topics in the domain of population ecology.

View Article: PubMed Central - PubMed

Affiliation: Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, CZ 612 64 Brno, Czech Republic.

ABSTRACT
Radiotracking is an important and often the only possible method to explore specific habits and the behaviour of animals, but it has proven to be very demanding and time-consuming, especially when frequent positioning of a large group is required. Our aim was to address this issue by making the process partially automated, to mitigate the demands and related costs. This paper presents a novel automated tracking system that consists of a network of automated tracking stations deployed within the target area. Each station reads the signals from telemetry transmitters, estimates the bearing and distance of the tagged animals and records their position. The station is capable of tracking a theoretically unlimited number of transmitters on different frequency channels with the period of 5-15 seconds per single channel. An ordinary transmitter that fits within the supported frequency band might be used with BAARA (Biological AutomAted RAdiotracking); an extra option is the use of a custom-programmable transmitter with configurable operational parameters, such as the precise frequency channel or the transmission parameters. This new approach to a tracking system was tested for its applicability in a series of field and laboratory tests. BAARA has been tested within fieldwork explorations of Rousettus aegyptiacus during field trips to Dakhla oasis in Egypt. The results illustrate the novel perspective which automated radiotracking opens for the study of spatial behaviour, particularly in addressing topics in the domain of population ecology.

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Related in: MedlinePlus

RSSI recording from individual antennas, averaged signal used for pulse detection (in red), the result of the convolution function (blue) and the best match (black): a) strong signal, good signal-to-noise ratio (35.1dB); b) weak signal, but recognisable (3.2dB); c) too weak signal (1dB), signal is lost and the detection fails; d) good signal but due to the inaccurate pulse timing, the detection fails.
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pone.0116785.g003: RSSI recording from individual antennas, averaged signal used for pulse detection (in red), the result of the convolution function (blue) and the best match (black): a) strong signal, good signal-to-noise ratio (35.1dB); b) weak signal, but recognisable (3.2dB); c) too weak signal (1dB), signal is lost and the detection fails; d) good signal but due to the inaccurate pulse timing, the detection fails.

Mentions: The first step of the position evaluation is a detection of the repetitive pulse pattern as it is generated by the telemetry transmitter. For this step, the signals from all antennas are summed together to form an averaged RSSI recording (note the red waveform in Fig. 3a–d). Note that the averaging reduces the random noise in the RSSI and yields more data for further steps. Using a numeric convolution [23], this sum is then compared with the expected pulse waveform (given by known pulse timing), to detect the pulses in the noise background. The detected coincidence (the bold blue waveform in Fig. 3a–d) enables the estimation of the RSSI during the pulse (RSSIon) and during the silence period (RSSIoff) and their difference is referred to as the signal-to-noise ratio. When the ratio, referred to as an acceptance threshold, is higher than ~4 dB (the precise threshold is estimated for each terrain deployment as shown later in this text), the position reading is considered valid. Fig. 3a shows the pulse detection on a strong signal; note that the result of the convolution function has one strong peak. Near the detection threshold (Fig. 3b), there is only a slight indication of the pulses in the averaged signal and almost no clue in the signals from individual antennas; the detection is still reliable. When the ratio is even lower (Fig. 3c), the pulses are indistinguishable from the noise. One very important aspect is the correct timing setting: the detection fails for signals with slightly changed pulse timing (by 5%, Fig. 3d) and indicates a low signal-to-noise ratio.


The BAARA (Biological AutomAted RAdiotracking) system: a new approach in ecological field studies.

Řeřucha Š, Bartonička T, Jedlička P, Čížek M, Hlouša O, Lučan R, Horáček I - PLoS ONE (2015)

RSSI recording from individual antennas, averaged signal used for pulse detection (in red), the result of the convolution function (blue) and the best match (black): a) strong signal, good signal-to-noise ratio (35.1dB); b) weak signal, but recognisable (3.2dB); c) too weak signal (1dB), signal is lost and the detection fails; d) good signal but due to the inaccurate pulse timing, the detection fails.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4340905&req=5

pone.0116785.g003: RSSI recording from individual antennas, averaged signal used for pulse detection (in red), the result of the convolution function (blue) and the best match (black): a) strong signal, good signal-to-noise ratio (35.1dB); b) weak signal, but recognisable (3.2dB); c) too weak signal (1dB), signal is lost and the detection fails; d) good signal but due to the inaccurate pulse timing, the detection fails.
Mentions: The first step of the position evaluation is a detection of the repetitive pulse pattern as it is generated by the telemetry transmitter. For this step, the signals from all antennas are summed together to form an averaged RSSI recording (note the red waveform in Fig. 3a–d). Note that the averaging reduces the random noise in the RSSI and yields more data for further steps. Using a numeric convolution [23], this sum is then compared with the expected pulse waveform (given by known pulse timing), to detect the pulses in the noise background. The detected coincidence (the bold blue waveform in Fig. 3a–d) enables the estimation of the RSSI during the pulse (RSSIon) and during the silence period (RSSIoff) and their difference is referred to as the signal-to-noise ratio. When the ratio, referred to as an acceptance threshold, is higher than ~4 dB (the precise threshold is estimated for each terrain deployment as shown later in this text), the position reading is considered valid. Fig. 3a shows the pulse detection on a strong signal; note that the result of the convolution function has one strong peak. Near the detection threshold (Fig. 3b), there is only a slight indication of the pulses in the averaged signal and almost no clue in the signals from individual antennas; the detection is still reliable. When the ratio is even lower (Fig. 3c), the pulses are indistinguishable from the noise. One very important aspect is the correct timing setting: the detection fails for signals with slightly changed pulse timing (by 5%, Fig. 3d) and indicates a low signal-to-noise ratio.

Bottom Line: This new approach to a tracking system was tested for its applicability in a series of field and laboratory tests.BAARA has been tested within fieldwork explorations of Rousettus aegyptiacus during field trips to Dakhla oasis in Egypt.The results illustrate the novel perspective which automated radiotracking opens for the study of spatial behaviour, particularly in addressing topics in the domain of population ecology.

View Article: PubMed Central - PubMed

Affiliation: Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, CZ 612 64 Brno, Czech Republic.

ABSTRACT
Radiotracking is an important and often the only possible method to explore specific habits and the behaviour of animals, but it has proven to be very demanding and time-consuming, especially when frequent positioning of a large group is required. Our aim was to address this issue by making the process partially automated, to mitigate the demands and related costs. This paper presents a novel automated tracking system that consists of a network of automated tracking stations deployed within the target area. Each station reads the signals from telemetry transmitters, estimates the bearing and distance of the tagged animals and records their position. The station is capable of tracking a theoretically unlimited number of transmitters on different frequency channels with the period of 5-15 seconds per single channel. An ordinary transmitter that fits within the supported frequency band might be used with BAARA (Biological AutomAted RAdiotracking); an extra option is the use of a custom-programmable transmitter with configurable operational parameters, such as the precise frequency channel or the transmission parameters. This new approach to a tracking system was tested for its applicability in a series of field and laboratory tests. BAARA has been tested within fieldwork explorations of Rousettus aegyptiacus during field trips to Dakhla oasis in Egypt. The results illustrate the novel perspective which automated radiotracking opens for the study of spatial behaviour, particularly in addressing topics in the domain of population ecology.

Show MeSH
Related in: MedlinePlus