Aerospace and Electronic Systems Magazine March 2017 - 2

In This Issue - Technically
REFINING FAULT TREES USING AVIATION DEFINITIONS FOR CONSEQUENCE SEVERITY
As an alternative to conventional fault trees, where system components are classified as either faulted or fault-free, this paper
introduces a multi-level analysis that maps directly into aviation definitions for consequence severity (including minor, major,
hazardous and catastrophic conditions). The key enabler for the new method, which we dub Consequence Severity Level (CSL)
analysis, is the substitution of specialized modifier gates in place of the traditional AND gate used in binary fault-trees. An unmanned aircraft example demonstrates how accounting for severity levels can relax certain design requirements by as much as
two orders of magnitude.

COLTANO: THE FORGOTTEN STORY OF ONE OF MARCONI'S EARLY POWERFUL INTERCONTINENTAL STATION
"There, do you see Admiral?" Marconi stated. "On that far plain, behind Leghorn, a large Italian radio station could be built, even
larger than the British station in Poldhu." There the story begins. On September 8, 1902, at the dawn of wireless telegraphy age,
Marconi was looking at the Tuscan coast from the cruiser "Carlo Alberto," back from a long trip where he successfully carried
out many radio experiments in the northern seas. While passing in front of Leghorn Marconi expressed to the Admiral Mirabello
his intention to build a powerful intercontinental station in the plain behind that city. The station, which would be the first in Marconi's home country (and one of the first in the world, too) was intended to provide radiotelegraphic connections with Africa and
America in the very low-frequency (VLF) band, i.e., using carrier frequencies below 100 kHz, which, at the time, were believed
to be the sole option for long-distance radio communications.

DESIGN AND IMPLEMENTATION OF CLOSED LOOP CONTROL SYSTEM FOR BUCK CONVERTER USING DIFFERENT
TECHNIQUES
A DC-DC buck converter is employed to develop a regulated voltage or current, derived from an unregulated power supply, or a
battery. Instances of these applications include battery chargers, electronic air purifiers, emergency exit signs, distributed power
systems, and renewable energy solar cell. This paper presents different control techniques for voltage mode controlled (VMC)
DC-DC switching buck converter. These controllers are Integral (I) controller, proportional plus integral (PI) controller, fuzzy
logic controller (FLC)and tuned fuzzy logic controller (TFLC).The design and simulation of a buck converter using MATLAB/
Simulink, Proteus and miKroC programs are presented. Comparative study results show that TFLC is superior compared with
the other control strategies, because of the fast transient response, and good disturbance rejection under various variations of the
operating conditions.

COMPLEMENTARY PAIR RADAR WAVEFORMS - EVALUATING AND MITIGATING SOME DRAWBACKS
Radar waveforms based on complementary pulse pairs produce the highly desired sidelobe-free range response. Yet their use is
limited because of several drawbacks: (a) Strong sensitivity to Doppler; (b) Incompatibility to pulse cancellers, an important processing step in Moving Target Identification (MTI); (c) High spectral sielobes, associated with phase coding. This tutorial paper
demonstrates those drawbacks and suggests mitigation methods to the latter two.

THE ROLE OF CHIEF TECHNOLOGY OFFICE (CTO) IN A MODERN DEFENSE COMPANY
The Chief Technology Office (CTO) is one of the key roles within any company. It is quite interesting to note that many interpretations exist for the responsibilities and related tasks assigned to the CTO, see for reference. This article outlines the duties of the CTO
within a modern defense company, relying on the multi-year experience gained by the authors in acting as CTO at different levels
of a company organization. The numerous and far-reaching duties of the CTO suggest that a "distributed" CTO functions spread
over various organization levels within a company, as opposite to a more conventional central CTO function is the most effective.

AUTONOMOUS QUADROTOR FOR ACCURATE POSITIONING
work shows the design of an autonomous Unmanned Aerial Vehicle (UAV) capable of executing takeoff, flight and landing without the need of a qualified pilot. A companion computer was embedded into the UAV to perform calculations based on image
algorithms tracking a marker where the vehicle should land. The algorithms were developed in Robot Operating System (ROS),
which is a well-known framework for robotics development. An optical flow module was used with the Global Positioning System (GPS) data to enhance the UAV geolocation estimation. The enhancement was around 56%.

IEEE A&E SYSTEMS MAGAZINE

MARCH 2017

Table of Contents for the Digital Edition of Aerospace and Electronic Systems Magazine March 2017