【正文】 ment. In this section we discuss our techniques for energy management, at the software level and the hardware level as well for wildCENSE. An instance of the node’s power consumption is shown in Figure 4. The details of energy consumption calculation are given in part C of this section. A. Hardware Level Energy Management The desired node is populated by number of sensors along with other peripheral including RTC, external flash memory and radio transceiver. Designing a simple power supply for such plex system was a challenge. All ponents and sensors were carefully selected to have low energy profile and almost similar input supply range with as the mon voltage. The system is powered by a rechargeable Liion battery, which can safely have voltages from V to V. Solar power is being added to further enhance the node life. Also the unused pins and digital input buffers are configured as output pins and disabled respectively, to minimize their energy leakage. The decision of using a mon voltage () not only made the power supply for the node simple but also saved lots of energy, which otherwise, would have been wasted in regulating it for different voltages. To utilize the battery energy to the maximum, a DC/DC converter, TPS63001 buck booster from Texas Instruments [17], is used. It provides a constant output with a maximum of of current。第 5 列 ―T‖給所采取的傳感器及其它外 設(shè)單次讀出 的典型時間（單位為秒）。 隨著微控制器 ，其他 外圍設(shè)備也提出休眠模式，以最大限度地減少能源的使用 。 圖 4 野外感知系統(tǒng)節(jié)點的功耗必比例圖 級別 的能源管理 理想的檢測 節(jié)點 包涵一定 數(shù)量的傳感器沿與其他外圍設(shè)備， 如 RTC，外部 閃存和無線電收發(fā)信機(jī)。節(jié)點 大部分時間 都 保持在休眠 /無效模式。 附加 的傳感器 ,為了收集沼鹿周圍 環(huán)境 的參數(shù) ， 從大鴨島上的經(jīng)驗試驗 [1]中得知我們需要在節(jié)點上安裝數(shù)字傳感器 。拉森 IQ GPS 支持 NMEA 協(xié)議的 GPRMC 通信形式。這個組件 由如下的 一個單個節(jié)點 組成 : 微控制器 ——ATMega1281V[7],128 k 字節(jié)程序內(nèi)存 ,是核心處理單元的設(shè)計。 用于測量溫度、濕度 ,和光線以及動物活動的傳感器也同時安裝在了 系統(tǒng) 里 。捕獲的數(shù)據(jù) 可以提供給野生動物研究人員讓他們完成 研究 和學(xué)習(xí)的目 。 為了從對野生動物監(jiān)測中尋到解決問題的方法 和了解 動物與其周圍環(huán)境的 復(fù)雜的關(guān)系 ,科學(xué)家必須 親自到現(xiàn)場去收集所需要的數(shù)據(jù) ?；?GPS的 動物跟蹤系統(tǒng) 1摘要： 野外 感知系統(tǒng) 是一種用于監(jiān)測沼澤鹿行為和遷徙模式的無線傳感網(wǎng)。在某些情況下 將無線電發(fā)射機(jī)安置動物身上能讓研究 變得更加容易 ,但是 圖像 的大部分仍然不能被標(biāo)記出來，因為缺少 有 效的數(shù)據(jù)收集 。它將有助于他們理解瀕危物種的 需求 ,以及這些物種與周圍的環(huán)境 關(guān)系 。 數(shù)據(jù)傳輸和恢復(fù) : 分散的數(shù)據(jù)只有在被傳播到基站 (s)的情況下才能被科學(xué)家收集起來用于分析 。它有 4 k 字節(jié)的 eepm 和 8 k 字節(jié)的存儲器。這一通信協(xié)議包涵了所有需要的內(nèi)容， 即日期、緯度、經(jīng)度和時間。濕度傳感器有內(nèi)置的加熱器 用于 蒸發(fā)吸收水。 以 一個產(chǎn)生周期性中斷 的 實時時鐘（ RTC）為 基礎(chǔ) ， 從的傳感器和 GPS 上收集所需的數(shù)據(jù) 。 為這樣復(fù)雜的系統(tǒng) 設(shè)計一個簡單的電源供應(yīng)器是一個 巨大的 挑戰(zhàn)。當(dāng) 節(jié)點是在睡眠模式 時 GPS 被關(guān)閉。最后一列，即 ―C‖是 在不同的模式下 各個組件 每天 的 電流 需 求（ mAh）。 being rated up to 96 percent efficient. Figure 4. Power Consumption breakdown of a wildCENSE node B. Software Level Energy Management wildCENSE employs ―Power Down‖ sleep mode of the microcontroller for the time the node is inactive, thereby saving substantial amount of energy. Another option could be to use a dual clock scheme instead of sleep mode, but while using an external Real Timer Clock, we are able to save the required power in our ―Power Down‖ sleep mode itself. The Power Down mode features putting everything to a plete shutdown, including the clock source [7] and typically consumes less than 10uA of current with ―Watchdog‖ enabled at . Brownout detector remains the only analog module in terms of power consumption during a sleep mode state [18]. But since even this module is not required in our design we have turned it permanently off ensuring further lower powered “ Power Down‖ sleep mode. Another power saving mode, the “ Power Save‖ sleep mode is employed when smaller delays are required between processing and reading sensors. Along with microcontroller other peripheral are also put to sleep mode to minimize energy usage. The GPS is switched off while the node is in sleep mode. This is implemented by the use of power switch, TPS2092 [19]. The application being not very time critical gives us the opportunity to put the radio transceiver in lowest power mode which consume about 5 times less power than the other modes. C. Node lifetime estimation Table 1 explains the power requirement of various ponents of the node. The following assumptions have been taken in estimating the energy requirements of the node for it to survive minimum of one year: ? The node takes measurements every 3 hrs. ? It is assumed that most of the time, the Barasingha, would be under open skies, getting a clear GPS lock. ? The node tries to discover other nodes/base every hour, synchronized by the RTC. ? Only 70 percent of the total rated Liion battery energy has been assumed usable [20]. ? Lastly, we assume that a node per day will receive a maximum of 7 pages from its peers and transfer one page to the other. In a month’s time the node will transfer all its content to the base With the above assumptions and using the stated hardware, the node requires a total of energy per day or 7040 mAh in a year. To meet the above requirements, Liion battery pack of 8Ah capacity is sufficient. Solar charging would further improve the life time of nodes. In the Table 1 we will represents Transmit mode by ―Tx‖, Receive mode by ―Rx‖ and Power Down by ―PD‖. The average current (in milli Ampere) requirements of ponents in different modes are given in Column 4. Column 5 ―T‖ gives the typical time (in sec) taken by sensors and other peripheral to take single reading. Last column . ―C‖ is the per day current requirements (mAh) of ponents in different mode. TABLE I. NODE LIFETIME ESTIMATION IV. CONCLUSION This paper presents an operational prototype for wildlife monitoring using WSN. wildCENSE is pact, accurate and does energy efficient sensing. Besides being energy efficient, it provides detailed position logs with a very high accuracy. The software protocols and the hardware implementation have all been carefully crafted to optimize the systems energy requirement. Though units like the GPS and Radio transceiver consume considerable energy, utilizing the sol。 野外感應(yīng)是一種 緊湊，準(zhǔn)確，高效節(jié)能的感