【正文】 ity 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 an external crystal of MHz is used. (limiting baud error to zero percent [7]). Real Time Clock DS3231 [8] For node discovery, all the nodes need to wake up at the same time requiring them to be synchronized. External RTC is required to accurately synchronize these nodes. It also generates periodic interrupts to wake up the microcontroller from its “Power Down” sleep mode. Features like extreme accuracy, integrated temperature pensated crystal oscillator (TCXO), I2C interfacing at different baud rates make the device ideal for this application. Any mismatch in the time in the system (between two interacting nodes) can cost a lot of power in network synchronization. RTC running on different nodes are skewed due to the environment. To maintain the accuracy of node to node munications, the RTC is synchronized by the GPS device every five days, keeping the clock skew within 1 sec. GPS – Lassen iQ GPS Receiver with antenna [9] – It has a small footprint, low energy consumption (89mW at ) in active mode. To achieve high accuracy, it uses twelve processing channels to track the GPS satellite signals. Lassen iQ GPS supports the required NMEA protocol with GPRMC message format, which contains all the required information namely date, latitude, longitude and time. It serially municates with the microcontroller at 4800 bps. Our GPS is used in On/Off mode since readings are taken every 3 hours. To utilize “Warm start” feature of GPS, we use a battery backup mechanism. Radio Transceiver – XBeePro [10] This DigiKey munication module is based on ZigBee/IEEE standard. It operates at (only freely available ISM band in India), providing a range of more than a kilometer. While using this frequency results in higher power consumption for same range pared to 900 MHz, we gain in terms of much higher data rate and smaller pact antenna. Low cost, low power and ease of use are among the other advantages. It also provides five sleep modes to meet various needs of different applications. We use lowest power sleep mode as it is not a time but power critical system. Delay of few milliseconds of wake up are well within the system’s toleranceFigure 2. wildCENSE Hardware setup depicting various ponents, their interfacing and power supply. Memory – ATMEL AT45DB16B Data flash [11] A high memory storage is required to plement the long latency of munication between the base and the node. For our WSN, a node needs to collect data from its peers, asking for a higher memory capacity. AT45DB16B, with SPI interfacing looks quite promising for the scenario. An operational inhouse developed file system [12], based on UCBs Matchbox file system [13], is being used, which makes the storage system simple and efficient. Additional sensors To collect the ambient environment parameters of the animal, the node mostly incorporates digital sensors, as from the experiences of Great Duck Island Experiment [1]. The humidity sensor has an inbuilt heater to evaporate absorbed water. Among the set of sensors are the Sensirion’s SHT11 [14] which is a digital temperature and humidity sensor (Resolution: 176。 Wireless Sensor Networks。雖然GPS和無線電收發(fā)器等單元要消耗相當(dāng)大的能源，但是利用太陽能充電機(jī)制，節(jié)點(diǎn)壽命將大為提高。表1 節(jié)點(diǎn)壽命估計(jì)IV 總結(jié)本文提出了一種用于監(jiān)測野生動物的無線傳感網(wǎng)操作原型。在表1中，我們將用“TX”代表發(fā)送模式，“RX” 代表接收模式和“PD”代表斷電模式。在一個(gè)月的時(shí)間里，該節(jié)點(diǎn)把它的所以數(shù)據(jù)都傳輸給基站。?假設(shè)，大部分的時(shí)候，沼鹿活動在露天的環(huán)境里，可得到一個(gè)明確的GPS位置信息。這是通過電源開關(guān)TPS2092[19]來實(shí)現(xiàn)的。但是，因?yàn)樽詮脑撃K在我們的設(shè)計(jì)中不需要以后，我們已經(jīng)把它永久關(guān)閉，確保進(jìn)一步降低 “斷電”睡眠模式的供電。當(dāng)節(jié)點(diǎn)處于非活動狀態(tài)時(shí)，野外感知系統(tǒng)采用微控制器的“關(guān)機(jī)”睡眠模式，從而節(jié)省了大量的能源。此外，未用引腳和數(shù)字輸入緩沖器分別被配置成輸出引腳和禁用，最大限度地減少他們的能源泄漏。為這樣復(fù)雜的系統(tǒng)設(shè)計(jì)一個(gè)簡單的電源供應(yīng)器是一個(gè)巨大的挑戰(zhàn)。在本節(jié)中，我們將在軟件和硬件水平上討論我們的能源管理技術(shù)，和野外感知體系。微控制器和無線收發(fā)信機(jī)之間的通訊波特率被設(shè)置為57600，雖然這個(gè)無線電收發(fā)機(jī)也支115200的波特率。當(dāng)GPS處于開機(jī)狀態(tài)，并在修理的過程， 如果附近有節(jié)點(diǎn)/基站則可以無線電進(jìn)行數(shù)據(jù)的傳輸。以一個(gè)產(chǎn)生周期性中斷的實(shí)時(shí)時(shí)鐘（RTC）為基礎(chǔ)，從的傳感器和GPS上收集所需的數(shù)據(jù)。節(jié)點(diǎn)的大小為56平方厘米，僅重34gms。為了降低ADC的噪聲，一個(gè)LC濾波器（L =10MH和C=）已被添加到的ADC引腳的微控制器。我們使用一個(gè)TAOS的TSL2561t[15]這是一款高靈敏度的數(shù)字光傳感器。濕度傳感器有內(nèi)置的加熱器用于蒸發(fā)吸收水。對于我們的無線傳感器網(wǎng)絡(luò),一個(gè)節(jié)點(diǎn)需要收集的數(shù)據(jù)來自同行,這要求更高內(nèi)存容量。它還提供了五個(gè)睡眠模式來滿足不同應(yīng)用場合的需求。無線電收發(fā)機(jī)——XBeePro[10]——這個(gè)數(shù)碼網(wǎng)絡(luò)關(guān)鍵通信模式是基于IEEE ZigBee /標(biāo)準(zhǔn)。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(shí)間。為了維護(hù)節(jié)點(diǎn)與節(jié)點(diǎn)之間通信的準(zhǔn)確性,RTC與GPS設(shè)備每五天實(shí)現(xiàn)一次同步,保持1秒內(nèi)的時(shí)鐘偏差。它還產(chǎn)生周期性的中斷來將微控制器從“斷電”睡眠模式中喚醒。當(dāng)連續(xù)通信是，內(nèi)部諧振器是不夠準(zhǔn)確， MHz的晶振。這個(gè)組件由如下的一個(gè)單個(gè)節(jié)點(diǎn)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(jì)。III．系統(tǒng)概述大體上生物傳感網(wǎng)系統(tǒng)分為如圖1所示的幾個(gè)部分,即硬件、相關(guān)系統(tǒng)軟件和驅(qū)動器,中間設(shè)備服務(wù)器連接數(shù)據(jù)記錄和web主機(jī)服務(wù)設(shè)備最后基于瀏覽器的可視化軟件。而且,由于在節(jié)點(diǎn)的重量上有一個(gè)限制,就不能提供一個(gè)巨大的電源供應(yīng)。為了解決這個(gè)問題,我們需要通過移動網(wǎng)絡(luò),采用點(diǎn)對點(diǎn)通信方式是試圖在無線卡插槽上傳輸數(shù)據(jù)[2]。研究人員指定的位置每3個(gè)小時(shí)能發(fā)生三次GPS位置信息就足以繪畫出這個(gè)動物的近一年的運(yùn)動軌跡周圍環(huán)境:由于在過去的一年里沼鹿的遷徙受地面植被的覆蓋率的影響,所以研究人員還需要監(jiān)控動物的居住和覓食環(huán)境。也可以說成是一項(xiàng)對動物的活動的研究。這個(gè)項(xiàng)圈會從附近動物中收集到科學(xué)研究所需要的數(shù)。特別是它把設(shè)計(jì)和測試系統(tǒng)時(shí)遇到的問題也體現(xiàn)了出來。這個(gè)系統(tǒng)中配有GPS、無線收發(fā)器和其他各種傳感器、硬件為支持野生動物監(jiān)控的需要而設(shè)計(jì)的。通過以上經(jīng)驗(yàn)的學(xué)習(xí)，我們可以知道生物感知網(wǎng)絡(luò)的構(gòu)建也是出于同樣的出發(fā)點(diǎn)。它不僅費(fèi)時(shí)而且需要花費(fèi)大量的資金來跟蹤動物遷移以及其飲食習(xí)慣。首先,研究物種時(shí)要做到完全避免人類干擾幾乎是不可能的。過去已經(jīng)見過各種各樣的無線傳感器網(wǎng)絡(luò)應(yīng)用于棲息地監(jiān)控、地震檢測,環(huán)境監(jiān)測、健康系統(tǒng)監(jiān)統(tǒng)等,這些領(lǐng)域很少會遇到移動節(jié)點(diǎn),動態(tài)網(wǎng)絡(luò)拓?fù)?通信失敗,電力供應(yīng)有限,惡劣的環(huán)境條件變化等情況。把微型傳感器、微控制器、無線電收發(fā)機(jī)和一種帶有電源,低功耗和廉價(jià)的傳感器節(jié)點(diǎn)(我們將簡單地稱之為節(jié)點(diǎn))結(jié)合可以用于監(jiān)視物理或環(huán)境的條件,如不同位置上的溫度、聲音、振動、壓力、運(yùn)動等。無線電收發(fā)機(jī)通過點(diǎn)對點(diǎn)的通信協(xié)議將數(shù)據(jù)傳送到基站?；臼褂镁W(wǎng)關(guān)，將收集到的所有數(shù)據(jù)上傳到互聯(lián)網(wǎng)上的一個(gè)數(shù)據(jù)庫和用基于可視化軟件的瀏覽器將這些信息描繪出來。該系統(tǒng)將收集微氣候以及動物的位置信息，并將這些信息以數(shù)據(jù)流的方式使用點(diǎn)對點(diǎn)網(wǎng)絡(luò)傳達(dá)到基站。一個(gè)外部數(shù)據(jù)閃存空間將會用于記錄從傳感器和網(wǎng)絡(luò)節(jié)點(diǎn)上獲取的數(shù)據(jù)。關(guān)鍵詞：GPS跟蹤；野外感知系統(tǒng)；無線傳感網(wǎng)，野生動物跟蹤，微型氣候感知器無線傳感器網(wǎng)絡(luò)(WSN)總是使用從分布式自治節(jié)點(diǎn)空間獲得的感知。這篇文章的重點(diǎn)就是如何通過對數(shù)據(jù)的處理，改善無限傳感網(wǎng)的設(shè)計(jì)來突破無限 傳感網(wǎng)在能量方面的束縛。有許多理由去解釋為什么頻繁的到現(xiàn)場去做調(diào)查是困難和不明智的。最后, 如果不使用專用的低成本傳感器網(wǎng)絡(luò)設(shè)備。一