Sensor Localization Using Time of Arrival Measurements in a Multi-Media and Multi-Path Application of In-Situ Wireless Soil Sensing

The problem of localization of nodes of a wireless sensor network placed in different physical media (anchor nodes above ground and sensor nodes underground) is addressed in this article. We use time of arrival of signals transmitted between neighboring sensor nodes and between satellite nodes and sensor nodes as the ranging measurement. The localization problem is formulated as a parameter estimation of the joint distribution of the time of arrival values. The probability distribution of the time of arrival of a signal is derived based on rigorous statistical analysis and its parameters are expressed in terms of the location coordinates of the sensor nodes. Maximum likelihood estimates of the nodes’ location coordinates as parameters of the joint distribution of the various time of arrival variables in the network are computed. Sensitivity analysis to study the variation in the estimates with respect to error in measured soil complex permittivity and magnetic permeability is presented to validate the model and methodology.

New data on the age of the Middle Palaeolithic site of Proniatyn (Podolian Upland)

The Middle Palaeolithic site Proniatyn is geomorphologically located on the near-watershed slope of the right bank of the Seret River. The history of its archaeological research began in 1977. During numerous expedition seasons of works conducted with using of methods of natural sciences and archaeology (until 2015), rich flint material was found on the site, which was located in the deposits of the over-Horokhiv deluvial solifluction stratum, i.e. not in situ, but was moved down the slope. The upper chronological limit of the cultural horizon was determined as 85±7 ka (according to V. Shovkoplias) by TL-dating of the Upper Pleistocene loess, which overlaps the over-Horokhiv deluvial solifluction stratum. In 2015, the Proniatyn site became the subject of scientific excursion of the international loess seminar «Loesses and Palaeolithic of Podillia». To clarify the age of the site, survey pit 5, located directly next to the main excavation, in the southern part of the site was expanded and deepened. The main goal of the work was to search for artifacts in the Horokhiv fossil pedocomplex (MIS 5), which is only slightly disturbed by deluvial-solifluctional processes. Two artifacts were found in the eluvial horizon of this complex, the third one was found in its humus horizon. Detailed analysis of the finds shows that the additional flint artifacts discovered in 2015 do not contradict the conclusion that technical, morphological and typological features of these three flints are completely identical to several thousand previously excavated flints from this site and represent the flake-blade Levallois industry. In general, all discovered artifacts from Proniatyn form a single monocultural complex of the site. Based on research conducted in 2015 is clearly established that the age of Proniatyn cultural horizon does not correspond to the age of deluvial-solifluctional strata, as previously thought, but is older than it. It is associated with the eluvial horizon of the Horokhiv fossil soil complex, the age of which is estimated at 112,0±11,2 ka and 106,7±11 ka according to TL-dating (the Palaeolithic site Yezupil I), 110±18 ka according to TL-dating and 102±16 ka according to OSL-dating (Palaeolithic site Mariampil I). Key words: Middle Palaeolithic, artifact, Mousterian, loess-palaeosol sequence, deluvial-solifluctional processes, Podillia.