5,228 research outputs found

    Position and Orientation Estimation through Millimeter Wave MIMO in 5G Systems

    Get PDF
    Millimeter wave signals and large antenna arrays are considered enabling technologies for future 5G networks. While their benefits for achieving high-data rate communications are well-known, their potential advantages for accurate positioning are largely undiscovered. We derive the Cram\'{e}r-Rao bound (CRB) on position and rotation angle estimation uncertainty from millimeter wave signals from a single transmitter, in the presence of scatterers. We also present a novel two-stage algorithm for position and rotation angle estimation that attains the CRB for average to high signal-to-noise ratio. The algorithm is based on multiple measurement vectors matching pursuit for coarse estimation, followed by a refinement stage based on the space-alternating generalized expectation maximization algorithm. We find that accurate position and rotation angle estimation is possible using signals from a single transmitter, in either line-of- sight, non-line-of-sight, or obstructed-line-of-sight conditions.Comment: The manuscript has been revised, and increased from 27 to 31 pages. Also, Fig.2, Fig. 10 and Table I are adde

    Spectral estimation on a sphere in geophysics and cosmology

    Full text link
    We address the problem of estimating the spherical-harmonic power spectrum of a statistically isotropic scalar signal from noise-contaminated data on a region of the unit sphere. Three different methods of spectral estimation are considered: (i) the spherical analogue of the one-dimensional (1-D) periodogram, (ii) the maximum likelihood method, and (iii) a spherical analogue of the 1-D multitaper method. The periodogram exhibits strong spectral leakage, especially for small regions of area A4πA\ll 4\pi, and is generally unsuitable for spherical spectral analysis applications, just as it is in 1-D. The maximum likelihood method is particularly useful in the case of nearly-whole-sphere coverage, A4πA\approx 4\pi, and has been widely used in cosmology to estimate the spectrum of the cosmic microwave background radiation from spacecraft observations. The spherical multitaper method affords easy control over the fundamental trade-off between spectral resolution and variance, and is easily implemented regardless of the region size, requiring neither non-linear iteration nor large-scale matrix inversion. As a result, the method is ideally suited for most applications in geophysics, geodesy or planetary science, where the objective is to obtain a spatially localized estimate of the spectrum of a signal from noisy data within a pre-selected and typically small region.Comment: Submitted to the Geophysical Journal Internationa

    PEER Arizona strong-motion database and GMPEs evaluation

    Get PDF
    This report summarizes the products and results of a study on the collection, processing, and analysis of earthquake ground-motions recorded in Arizona at several recording stations within 200 km from the Palo Verde Nuclear Generating Station in central Arizona. The recorded ground motion in Arizona were compiled and processed according to the Pacific Earthquake Engineering Research Center’s (PEER) record-processing standards. Shear wave velocity profiles at ten recording stations were measured through the spectral analysis of surface wave dispersion technique. Additionally, “kappa” a measure of energy dissipation in the top 1 to 2 km of the crust, was estimated by three methodologies. The average κ0 (kappa at zero-kilometer distance) was estimated from all sites as 0.033 sec. Finally, response spectra of the recorded ground motions in Arizona were compared with those predicted by the NGA-West2 ground motion prediction equations at large distances in Arizona. The comparison showed that overall the recorded 5% damped response spectral ordinates were over predicted by the NGA-West2 models by a range of 0-0.35 natural log units for events occurring in Central California, and by a range of 0.2-0.7 natural log units for events occurring in Southern California and the Gulf of California
    corecore