On magnetometer heading updates for inertial pedestrian navigation system

A magnetometer is often used to aid heading estimation of a low-cost Inertial Pedestrian Navigation System (IPNS) without which the latter will not be able to accurately estimate heading for more than a few seconds, even with the help of Zero Velocity Update (ZVU). Heading measurements from the magnetometer are typically integrated with gyro heading in an estimation filter such as Kalman Filter (KF) — to best estimate the true IPNS heading, resulting in a better positioning accuracy. However indoors the reliability of these measurements is often questionable because of the magnetic disturbances that can disrupt the measurements. To solve this problem, a filtering method is often used to select the best measurements. However, the importance of the frequency of these measurement updates has not been highlighted. In this paper, the impact of frequency of magnetometer updates on the overall accuracy of the navigation system is presented. The paper starts by discussing the use of a magnetometer in a low-cost IPNS. An exemplary filter to extract reliable heading measurements from the magnetometer is then described. From real field trial results, it will be shown that even if reliable heading measurements may be obtained indoors, it is still insufficient to increase the positioning accuracy of the low-cost IPNS unless it is reliable on every epoch

Generic programming

Abstract. Generic programming depends on the decomposition of programs into components which may be developed separately and combined arbitrarily, subject only to well-defined interfaces. Among the interfaces of interest, indeed the most pervasively and unconsciously used, are the fundamental operators common to all C++ built-in types, as extended to user-defined types, e.g. copy constructors, assignment, and equality. We investigate the relations which must hold among these operators to preserve consistency with their semantics for the built-in types and with the expectations of programmers. We can produce an axiomatization of these operators which yields the required consistency with built-in types, matches the intuitive expectations of programmers, and also reflects our underlying mathematical expectations

Stepanov, “Effect of uncertainty on continuous path planning for an autonomous vehicle

IEEE IEE

CA), pp 237–251. Loge: a self-organizing disk controller

While the task of organizing data on the disk has traditionally been performed by the file system, the disk controller is in many respects better suited to the task. In this paper, we describe Loge, a disk controller that uses internal indirection, accurate physical information, and reliable metadata storage to improve I/O performance. Our simulations show that Loge improves overall disk performance, doubles write performance, and can, in some cases, improve read performance. The Loge disk controller operates through standard device interfaces, enabling it to be used on standard systems without software modification....only craft and cunning will serve, such as Loge artfully provides. — Richard Wagner, Das Rheingold, Scene II

Algorithm-Oriented Generic Libraries

generic algorithms, algorithmic abstraction, software libraries, abstract datatypes, C++, templates We outline an approach to construction of software libraries in which generic algorithms (algorithmic abstractions) play a more central role than in conventional software library technology or in the object-oriented programming paradigm. Our approach is to consider algorithms first, decide what types and access operations they need for efficient execution, and regard the types and operations as formal parameters that can be instantiated in many different ways, as long as th

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