【文章內(nèi)容簡(jiǎn)介】 g. The captured data can be provided to the wildlife researchers for their research and study purposes. It will be helpful to them to understand the needs of the endangered species, and the relationship these species share with the surroundings. The paper fundamentally discusses the hardware and software design architecture of the wildCENSE system at the node, base and network levels. In particular, it embodies the issues and constraints, which were met during the design and testing of the system. II. GPS BASED ANIMAL TRACKING SYSTEM The Barasingha is native to India and Nepal. Once it populated throughout the basins of the Indus, Ganges and Brahmaputra rivers, as well as parts of central India reaching out till the river Godavari. But in past few decades its population has declined significantly listing them as endangered species by IUCN from 1984 to 1996 and as vulnerable since 1996 [4]. Wildlife researchers while surveying Jhilmil Tall (Uttaranchal) area came across some 30 heads of the Barasingha on February 3, 2005 [5]. Trails indicate that they might have migrated across the Nepal border. But yet their exact migratory path is unknown。 hence it is important to monitor their movement and protect them. wildCENSE is an attempt towards discovering this path along with helping the researchers know more about their habitat. The input for the design of the system came from wildlife researchers. In the system proposed, specially designed lightweight collar, with sensor node attached, would be put on the animal. These collars would collect data about the desired parameters from the vicinity of the animal. The data may then be sent to other nodes or the base station, depending on the availability of either (base station getting a preference in case of both being available). The prime requirement is to track the migratory movement of the animal which is done using a Global Positioning System (GPS). Besides the location, the animal39。s habitat and its ambient environment parameters are of interest. Also a study of the animal’s activities viz. the grazing patterns of the animal needs to be recorded. Since the area under surveillance is large, the acquired data needs to be propagated on a node to node basis until it is transferred to a base station. Lastly the system needs to run continuously for a minimum of 12 months, so the power supply design and its usage need optimization. Positional Logs: The GPS reading needs to be accurate and precise, in view with the migration pattern of the animal. As researchers specify, a location reading every 3 hours would be enough to draw a close enough movement track of the animal over a year. Ambient Environment: With the animal covering a lot of ground during its migration over the year, the researchers also need to monitor the environment in which the animal dwells and grazes. Sensors for measuring the temperature, humidity, and light as well as animal activity are embodied in the system. Data Transmission and Recovery: To collect the dispersed data for analysis by the researchers, it needs to be transmitted to the base station(s). Since the Barasingha has a fairly large movement track it is not possible to equip the entire region with numerous base stations. To address this issue, the data needs to be moved through the network, employing node to node munications as was attempted in Zebranet[2]. In order to pensate for high latency, the node has a large external flash to acmodate data generated on the node as well as acquired through peer interaction. Section discusses the munication in more detail. Energy harvesting: The nodes need to be alive for a minimum of a year, tracking the migration path, avoiding any human intervention. Their only contact is the wireless link with other nodes or the base station as the case may be. Also, since there is a limitation on the weight of the node, a bulky power supply is forbidden. Hence, the node needs to have lightweight power back up system. Given that the animal will mostly be in large fields under open skies, the required power supply could be equipped with solar energy harvesting features. With careful energy management policy, supplemented by harvesting, the energy requirements can be easily met. The power supply is discussed in more detail in Section III. System Overview Broadly the wildCENSE system is divided as in Figure 1, namely the hardware, related system software and drivers, middleware servers with data logging and web hosting services and finally the browser based visualization software. 1) Hardware Architecture The plete sensor node along with the battery recharging system is in the form of a collar to be worn by the animal. Hardware system architecture of wildCENSE node is as depicted in Figure 2. The design issues as discussed in Section 2 have been carefully met. Each ponent has been carefully selected based on earlier prototypes to meet accuracy, power, voltage patibility and cost considerations [6]. The ponents that make up a single node are as follows:Microcontroller – ATMega1281V [7], with 128K bytes program memory, is the core processing unit of our design. It has 4K bytes of EEPROM and 8K bytes of SRAM. The availability of 2 USART ports enables independent Figure 1. wildCENSE System Overviewmunication of GPS and Radio transceiver with the core processing unit simultaneously. This allows us to remove the multiplexing overhead as described in the software section . The internal resonator is not accurate enough for serial munication, so a