Experimental impulse radio IEEE 802.15.4a UWB based wireless sensor localization technology: Characterization, reliability and ranging

Ultra Wide Band (UWB) transmission has recently been the object of considerable attention in the field of next generation location aware wireless sensor networks. This is due to its fine time resolution, energy efficient and robustness to interference in harsh environments. This paper presents a thorough applied examination of prototype IEEE 802.15.4a impulse UWB transceiver technology to quantify the effect of line of sight (LOS) and non line of sight (NLOS) ranging in real indoor and outdoor environments. Results included draw on an extensive array of experiments that fully characterize the 802.15.4a UWB transceiver technology, its reliability and ranging capabilities for the first time. A new two way (TW) ranging protocol is proposed. The goal of this work is to validate the technology as a dependable wireless communications mechanism for the subset of sensor network localization applications where reliability and precision positions are key concerns.

Stair na Gaeilge i gContae Thiobraid Árann 1700-1901

Stair na Gaeilge i gCo. Thiobraid Árann i rith na tréimhse 1700-1901 atá á ríomhadh sa tráchtas seo. Tar éis a cúlra agus a comhthéacs a shuíomh i gCaibidil a hAon, déantar scríobhaithe an cheantair a áireamh, fara tráchtaireacht orthu, i gCaibidil a Dó. I gCaibidlí a Trí agus a Ceathair, féachtar ar thionchar na hEaglaisí Caitlicí agus Eaglais na hÉireann (i measc eaglaisí Protastúnacha eile) ar an dteangain. I gCaibidil a Cúig, faightear spléachadh ar ghnéithe éagsúla de shaíocht an chontae, ag tabhairt léargais ar tháirgí na scríobhaithe, ar leabhair a clóbhualadh sa réigiún, agus ar fhilí móra na háite, leithéidí Liam Daill Uí Ifearnáin, ag sonrú limistéir faoi leith, an t-oirdheisceart, mar shampla. Léirítear éifeacht na gcumann Gaelach agus na ndíograiseoirí iomadúla a bhain leo. Ábhar suime, leis, feidhm na Gaeilge sna cúirteanna dlí. Tugtar faisnéis i gCaibidil a Sé ar fhianaise cuairteoirí ar an Ghaeilge mar urlabhra i dTiobraid Árann. Is anseo chomh maith a deintear anailís ar Dhaonáirimh na mblianta 1861-1901, le mórchuid adhmaid á baint as ceann 1901 go háirithe. Breactar as ainmneacha sagart agus múinteoirí le Gaeilge, agus tráchtar ar aicmí suntasacha eile, na póilíní agus na saighdiúirí a raibh an teanga sin ina mbéal acu. Tugtar le chéile dá réir na snáithíní difriúla eolais ar an dúiche ar bhealach nár tharla cheana don gcontae casta fairsing seo le haghaidh na tréimhse atá idir lámha ag an saothar.

Algorithms for indoor localization based on IEEE 802.15.4-2011 UWB and inertial sensors

In this thesis, extensive experiments are firstly conducted to characterize the performance of using the emerging IEEE 802.15.4-2011 ultra wideband (UWB) for indoor localization, and the results demonstrate the accuracy and precision of using time of arrival measurements for ranging applications. A multipath propagation controlling technique is synthesized which considers the relationship between transmit power, transmission range and signal-to-noise ratio. The methodology includes a novel bilateral transmitter output power control algorithm which is demonstrated to be able to stabilize the multipath channel, and enable sub 5cm instant ranging accuracy in line of sight conditions. A fully-coupled architecture is proposed for the localization system using a combination of IEEE 802.15.4-2011 UWB and inertial sensors. This architecture not only implements the position estimation of the object by fusing the UWB and inertial measurements, but enables the nodes in the localization network to mutually share positional and other useful information via the UWB channel. The hybrid system has been demonstrated to be capable of simultaneous local-positioning and remote-tracking of the mobile object. Three fusion algorithms for relative position estimation are proposed, including internal navigation system (INS), INS with UWB ranging correction, and orientation plus ranging. Experimental results show that the INS with UWB correction algorithm achieves an average position accuracy of 0.1883m, and gets 83% and 62% improvements on the accuracy of the INS (1.0994m) and the existing extended Kalman filter tracking algorithm (0.5m), respectively.