Background
Despite the increasing worldwide use of global positioning system (GPS) telemetry in wildlife research, it has never been tested on any freshwater diving animal or in the peculiar conditions of the riparian habitat, despite this latter being one of the most important habitat types for many animal taxa. Moreover, in most cases, the GPS devices used have been commercial and expensive, limiting their use in low-budget projects.
Methodology/Principal Findings
We have developed a low-cost, easily constructed GPS GSM/GPRS (Global System for Mobile Communications/General Packet Radio Service) and examined its performance in stationary tests, by assessing the influence of different habitat types, including the riparian, as well as water submersion and certain climatic and environmental variables on GPS fix-success rate and accuracy. We then tested the GPS on wild diving animals, applying it, for the first time, to an otter species (Lutra lutra). The rate of locations acquired during the stationary tests reached 63.2%, with an average location error of 8.94 m (SD = 8.55). GPS performance in riparian habitats was principally affected by water submersion and secondarily by GPS inclination and position within the riverbed. Temporal and spatial correlations of location estimates accounted for some variation in the data sets. GPS-tagged otters also provided accurate locations and an even higher GPS fix-success rate (68.2%).
Conclusions/Significance
Our results suggest that GPS telemetry is reliably applicable to riparian and even diving freshwater animals. They also highlight the need, in GPS wildlife studies, for performing site-specific pilot studies on GPS functioning as well as for taking into account eventual spatial and temporal correlation of location estimates. The limited price, small dimensions, and high performance of the device presented here make it a useful and cost-effective tool for studies on otters and other aquatic or terrestrial medium-to-large-sized animals.
I. INTRODUCTION, METHODOLOGY & PRODUCT DEFINITIONS
Study Reliability and Reporting Limitations I-1
Disclaimers I-2
Data Interpretation & Reporting Level I-2
Quantitative Techniques & Analytics I-3
Product Definitions and Scope of Study I-3
Land-Based Applications I-3
Aviation Applications I-4
Marine Applications I-4
Timing Applications I-4
II. EXECUTIVE SUMMARY
1. GLOBAL MARKET OVERVIEW II-1
Introduction II-1
Commercial GPS Gains Prominence II-2
Impact of Recession: In Retrospect II-2
Market Stages Quick Recovery in 2010 II-3
Outlook II-4
Developing Markets to Lend Traction in the Short to Medium
Term Period II-5
Trends & Issues II-5
Automobile Navigation Systems Gain Popularity II-5
GPS Technology Commands Increasing Usage in Fleet Management II-5
GPS Car Security Systems: Getting Smaller and Simpler II-6
Driverless Cars - A Bright Prospect for High- End GPS Based
In-Vehicle Navigation Systems II-6
Latest Mapping/Surveying Technologies Create New Market
Opportunities II-6
Low-Budget GPS Devices Rise in Popularity II-6
Personal Navigation Systems & Smartphones to Challenge
Dedicated GPS Units in the Commercial Market II-7
Trends in Mobile GPS Units that Threaten Superiority of
Stand-Alone Commercial GPS II-7
Mobile GIS Gaining Ground II-7
Technological Advancements & Price Declines Make Handheld
GPS Devices a Mass Market Proposition II-7
GPS Technology in Cellular Phones: New Frontiers II-8
Smartphone Mobile Navigation Increases II-9
GPS Chipsets to Form Integral Component of Cellular Phones II-9
Hardware Implementations Drive GPS Growth in the Cellular
Phone Market II-9
Smarter GPS Devices Outwit Traditional GPS Units - Attract
New Opportunities II-9
Tight Budgetary Conditions Help A-GPS Devices Score Over
Stand-Alone GPS Devices II-10
Challenged by GPS Enabled SmartPhones Traditional GPS Unit
Manufacturers Look to Innovate II-10