Bear Ethology Around Romania

Environmental factors which cause difficulty with, for example, GPS and/or Galileo signal reception include tree canopies and urban canyons. This project developed strategies to mitigate some of these environmental factors. Such problems arise naturally from the study of animal behaviour. The experimental 'vehicles' for this project were bears in the Transylvanian Alps. The project methodology was based on the comparison of different techniques for animal tracking – high sensitivity (multiple-correlators) and post-processing of pseudo-range signals. In practice, four bears were equipped with multi-mode receivers so that tracking signals could be compared. In addition, innovative algorithms were developed and evaluated for 'height-aiding'. In parallel, the bears were tracked by foresters and monitored visually. The major innovation related to post-processing techniques for the individual pseudo-range signals.

There is a problem with signal availability in environments where there is extensive tree cover. The purpose of the BEAR project was to develop improved tracking techniques for use in difficult GNSS environments. A secondary set of activities that was related to wildlife management used data derived from the core aspects of the project.

Description

The work had five components:

1. Developing tracking collars and the associated telemetry system to capture, store and transmit full pseudo-range information from the hostile environment of the Transylvanian mountains. Because of the initial uncertainties, provision was made for three types of telemetry and tracking: GSM radio based on SMS (the preferred option but problematic due to low signal strength in mountainous regions), UHF (less desirable due to the need to be relatively close to the bear(s) in order to download the data stream), and VHF (the least preferred solution as this requires triangulation and does not provide a data stream).
2. Ground survey and mapping of the terrain to be used by the bears, recognising that they are free to roam at will.
3. Analysis of the data to evaluate the performance of different types of receiver in a forested environment – specifically high-gain GPS receives utilising multiple correlators, and 'normal' receivers using standard technology.
4. Development and evaluation of new algorithms which exploit the concept of 'height-aiding' i.e. utilising knowledge of the terrain morphology (specifically its altitude) along tracks used by the bears.
5. Visual tracking and monitoring of the bears so that their behaviour could be correlated with the GPS results. This included diary records of the flora and fauna through which the bears travelled.

Objectives

The BEAR project relates to the development of innovative algorithms to improve signal availability for tracking in harsh GNSS environments. It includes the comparative evaluation of differing receiver strategies based on GPS and EGNOS: the innovation is based on the concept of advanced signal processing to derive improved tracking information from knowledge of the three-dimensional terrain and past history (time and spatial) of the track.

The experimental 'vehicles' were bears located in the mountains of Transylvania. The choice was dictated by the need to carry a relatively heavy payload in a difficult GNSS environment in terms of signal availability and continuity of coverage. It also provided a level of unpredictability of spatial behaviour that demanded true innovation from the algorithmic approach to signal processing.