In this dissertation we consider the problem of localization of wireless devices in environments
and applications where GPS (Global Positioning System) is not a viable
option. The rst part of the dissertation studies a novel positioning system based
on narrowband radio frequency (RF) signals of opportunity, and develops near optimum
estimation algorithms for localization of a mobile receiver. It is assumed that a
reference receiver (RR) with known position is available to aid with the positioning
of the mobile receiver (MR). The new positioning system is reminiscent of GPS and
involves two similar estimation problems. The rst is localization using estimates
of time-dierence of arrival (TDOA). The second is TDOA estimation based on the
received narrowband signals at the RR and the MR. In both cases near optimum
estimation algorithms are developed in the sense of maximum likelihood estimation
(MLE) under some mild assumptions, and both algorithms compute approximate
MLEs in the form of a weighted least-squares (WLS) solution. The proposed positioning
system is illustrated with simulation studies based on FM radio signals.
The numerical results show that the position errors are comparable to those of other
positioning systems, including GPS.
Next, we present a novel algorithm for localization of wireless sensor networks
(WSNs) called distributed randomized gradient descent (DRGD), and prove that in
the case of noise-free distance measurements, the algorithm converges and provides
the true location of the nodes. For noisy distance measurements, the convergence
properties of DRGD are discussed and an error bound on the location estimation
error is obtained. In contrast to several recently proposed methods, DRGD does
not require that blind nodes be contained in the convex hull of the anchor nodes,
and can accurately localize the network with only a few anchors. Performance of
DRGD is evaluated through extensive simulations and compared with three other algorithms,
namely the relaxation-based second order cone programming (SOCP), the
simulated annealing (SA), and the semi-denite programing (SDP) procedures. Similar
to DRGD, SOCP and SA are distributed algorithms, whereas SDP is centralized.
The results show that DRGD successfully localizes the nodes in all the cases, whereas
in many cases SOCP and SA fail. We also present a modication of DRGD for mobile
WSNs and demonstrate the ecacy of DRGD for localization of mobile networks with
several simulation results. We then extend this method for secure localization in the
presence of outlier distance measurements or distance spoong attacks. In this case
we present a centralized algorithm to estimate the position of the nodes in WSNs,
where outlier distance measurements may be present.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-04102014-142821 |
| Date | 09 May 2014 |
| Creators | Chacon Rojas, Gustavo Andres |
| Contributors | Naraghi-Pour, Morteza, Guoxiang, Gu, Wei, Shuangqing, Liang, Xuebin, Wilmot, Chester |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-04102014-142821/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
Page generated in 0.0014 seconds