Development of a robust real-time filtering algorithm for inertial sensor based navigation systems with zero velocity update

Currently many GPS (Global Positioning System) satellites orbit the Earth providing users with information on position anywhere in the world and in all weather conditions. Information is gathered from the orbiting satellites and is merged with information from base towers on earth to locate a person’s position. Although GPS is leading the navigation system industry it does suffer in that GPS signals are unable to pass through solid structures. This means GPS is unable to accurately work in dense urban areas or indoor environments. This research aims to develop a sensor based standalone indoor navigation system using a robust real-time filtering algorithm to accurately provide a person’s positions and movement. Despite the numerous research and development on indoor navigation systems, little work has been done on maximizing the accuracy of the indoor navigation systems for achieving pin-point localization. The system proposed within utilizes a foot mounted IMU (inertial measurement unit) comprised of several inertial sensors capable of tracking a wearer’s movements without satellite signals. IMU based systems, as with most other indoor navigation technologies, suffer from sensor “drift” during longtime navigation, which can cripple the system. This research aims to filter sensory data collected by an IMU system through an EKF (extended Kalman filter) to correct drift. An EKF is an optimal estimation algorithm capable of estimating dynamic variables of indirect and uncertain measurements. In the team’s endeavor to maximize the accuracy and efficiency of the algorithm they have found the integration of an EKF to be largely efficacious in mitigating drift error. As of right now, major drift error is still observed which overtime accumulates into false mapping, but solutions are in the process to mitigate this error. We feel that inertial based navigation systems, when paired with a real-time filtering algorithm, offer an alternative to GPS navigation far more conducive to indoor environment

Experimental Development of a Bat Inspired Obstacle Mapping System

This paper presents the development of an experimental method for obstacle detection using modified bat inspired navigation. Effective obstacle detection is vital to the efficient operation of many autonomous vehicles, mobile robotics and navigation systems. Varieties of sensors and sensor array combinations have been purposely developed to effectively detect and map obstacles and barriers during navigation [1][2]. Among these, ultrasonic sensors provide an inexpensive solution to distance and obstacle sensing. This is vital for industries such as automotive and transportation in which cost is a significant factor [3]. This work enhances the abilities of testing object classification capabilities of ultrasonic sensors through verification and proof of concept for bat-inspired, time of flight (TOF) based algorithms. Just as bats utilize acoustic echo to detect objects while navigating, this bat inspired system utilizes two static ultrasonic receivers and one central dynamic emitter. In our system, the electronic setup implemented was designed to activate a 40kHz emitter, capture the echo milliseconds later and incrementally move the emitter via the stepper motor. Upon activation of the emitter, the measurement device was triggered and the two distinct receiver signals were acquired. Receiver signals were then passed through a virtual low-pass filter and curve fitting algorithm in order to effectively and consistently determine the TOF values. Internal circuitry delays between trigger time and time of emission was accounted for through a test case with known orientation and speed of sound. Lastly the inherent nature of a diffuse detection surface permitted the detection of reflected signals from all emitter orientations. The experimental methodology developed in this research was successfully tested for detecting walls with a low cost ultrasonic emitter and receiver, setting a basis for analysis of future TOF based detection algorithms. The outcome of this research has the potential to provide effective barrier detection systems for autonomous navigation systems

Grammar-based object representations in a scene parsing task.

This paper addresses the nature of visual representations associated with complex structured objects, and the role of these representations in perceptual organization. We use a novel experimental paradigm to probe subjects intuitions about parsing a scene consisting of overlapping two-dimensional objects. The objects are generated from an abstract 2-dimensional image grammar, which specifies the set of possible configurations of object parts. We show that participants' performance on the task depends on prior experience with the object class, and based on structural cues. This indicates that structural representations exerted a top-down influence on parsing. To address the question of representation type, we used a computational model of object matching in conjunction with various probabilistic representational models. Our simulations indicate that grammar-based representations derived from the original grammars are superior to more restrictive exemplar-based representations in explaining human performance on this task, as well as to more inclusive, over-generalizing grammar-based representations

Effect of geometric and material properties on Thermoelastic Damping (TED) of 3D hemispherical inertial resonator

High quality factor (Q-factor) is a crucial parameter for the development of precision inertial resonators. Q-factor indicates efficiency of a resonator in retaining its energy during oscillations. This paper explores the effects of different design parameters on Q-factor of a 3D hemispherical (wine-glass) inertial resonator. Thermo-elastic damping (TED) loss mechanisms in a 3D non-inverted wine-glass (hemispherical) shell resonator is systematically investigated and presented in this paper. We investigated TED loss resulting from the effects of hemisphere geometric parameters (such as thickness, height, and radius), mass imbalance, thickness non-uniformity, and edge defects. We used glassblowing to fabricate hemispherical 3D shell resonators. The results presented in this paper can facilitate selecting efficient geometric and material properties for achieving desired Q-factor in 3D inertial resonators. Enhancing the Q-factor in MEMS based 3D resonators can further enable the development of high precision resonators and gyroscopes

Search for Scalar Diphoton Resonances in the Mass Range 65−60065-600 GeV with the ATLAS Detector in pppp Collision Data at s\sqrt{s} = 8 TeVTeV

A search for scalar particles decaying via narrow resonances into two photons in the mass range 65–600 GeV is performed using $20.3\text{}\text{}{\mathrm{fb}}^{-1}$ of $\sqrt{s}=8\text{}\text{}\mathrm{TeV}$ $pp$ collision data collected with the ATLAS detector at the Large Hadron Collider. The recently discovered Higgs boson is treated as a background. No significant evidence for an additional signal is observed. The results are presented as limits at the 95% confidence level on the production cross section of a scalar boson times branching ratio into two photons, in a fiducial volume where the reconstruction efficiency is approximately independent of the event topology. The upper limits set extend over a considerably wider mass range than previous searches

Measurements of the Total and Differential Higgs Boson Production Cross Sections Combining the H??????? and H???ZZ*???4??? Decay Channels at s\sqrt{s}=8??????TeV with the ATLAS Detector

Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3~fb$^{-1}$ of $pp$ collisions produced by the Large Hadron Collider at a center-of-mass energy of $\sqrt{s} = 8$ TeV and recorded by the ATLAS detector. Cross sections are obtained from measured $H \rightarrow \gamma \gamma$ and $H \rightarrow ZZ ^{*}\rightarrow 4\ell$ event yields, which are combined accounting for detector efficiencies, fiducial acceptances and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be $\sigma_{pp \to H} = 33.0 \pm 5.3 \, ({\rm stat}) \pm 1.6 \, ({\rm sys}) \mathrm{pb}$. The measurements are compared to state-of-the-art predictions.Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3  fb-1 of pp collisions produced by the Large Hadron Collider at a center-of-mass energy of s=8  TeV and recorded by the ATLAS detector. Cross sections are obtained from measured H→γγ and H→ZZ*→4ℓ event yields, which are combined accounting for detector efficiencies, fiducial acceptances, and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be σpp→H=33.0±5.3 (stat)±1.6 (syst)  pb. The measurements are compared to state-of-the-art predictions.Measurements of the total and differential cross sections of Higgs boson production are performed using 20.3 fb$^{-1}$ of $pp$ collisions produced by the Large Hadron Collider at a center-of-mass energy of $\sqrt{s} = 8$ TeV and recorded by the ATLAS detector. Cross sections are obtained from measured $H \rightarrow \gamma \gamma$ and $H \rightarrow ZZ ^{*}\rightarrow 4\ell$ event yields, which are combined accounting for detector efficiencies, fiducial acceptances and branching fractions. Differential cross sections are reported as a function of Higgs boson transverse momentum, Higgs boson rapidity, number of jets in the event, and transverse momentum of the leading jet. The total production cross section is determined to be $\sigma_{pp \to H} = 33.0 \pm 5.3 \, ({\rm stat}) \pm 1.6 \, ({\rm sys}) \mathrm{pb}$. The measurements are compared to state-of-the-art predictions