Mircea Cernat and Teodor-Viorel Chelaru
The paper analyses the evolution of rockets used to prevent hailstone formation in turbulent atmospheric conditions. After general definitions of the turbulent atmosphere and working hypotheses, a model of a uniform and linear turbulent atmosphere, obtained from analytical relations, is presented in detail. From this model, the components of velocity of turbulence are deduced as functions of time. Introducing the components of velocity into the model of simulation of the rocket flight, a fascicle of the trajectories is obtained. The fascicle is analysed as a statistical function in six different stages. The novelty in this work is in the technique used to model the turbulent atmosphere influence on unguided rocket flight.
Jill L. Drury and Erika Darling
Before modernizing any information-intensive system, it is important to understand how people are performing their jobs using that system. This understanding is built not simply by observing what people are doing, but by digging into how people think about their jobs, what coordination they need to do, and the dependencies among subtasks that together dictate a workflow. Building a thorough understanding of complex tasks takes weeks or months rather than days, but we needed to get as much of an understanding as possible in three days of a real-time command and control centre for military unmanned vehicles. To help structure our investigation, we used a technique called Applied Cognitive Task Analysis (ACTA) [14]. To the best of our knowledge, ours is the first use of ACTA to study a military command and control centre in such a time-compressed fashion. We describe our application of ACTA and the types of recommendations we were able to generate from our analysis, and provide reflections on the study process. Another contribution of this paper is based on the fact that we were able to gain access to a facility that is not usually open to researchers; hence the ACTA results may be of interest to those who would benefit from knowing about the major cognitive challenges facing members of the Predator Unmanned Aircraft System community.
Paul Axon, Steve Szybowski, Lesley Stanger, Allan Savins, Emmanuel de la Haye, John Phillips, and Craig Fuller
This paper describes the candidate technologies, processes and system engineering practices used by the Thales Australia Concept Technology Demonstrator (CTD SEA1660 project) on behalf of the Commonwealth of Australia for the investigation, design and testing of a broadband Naval Tactical Trunk (NTT) and report on progress to date. The objective is to enhance the capability of the Royal Australian Navy with mobile communications at speeds of greater than 2Mbps as high data-rate trunk communications accessible to military units operating within a littoral battlespace as well as in blue-water formation. We focus on the enhancement of high data-rate, mobile line-of-sight (LOS) communications available to military groups operating within the littoral zone, amphibious landings and deployments, naval task groups and mobile land forces considering the environmental, Defence spectrum management and link budget issues for both ship-to-ship and ship-to-shore scenarios. Although not intended for use as a capability system the NTT must satisfy all mandatory operational and safety requirements for testing and demonstration on board RAN ships. Three test terminals will demonstrate wideband communications channel technologies and algorithms for amphibious and at-sea communications and data capture within Thales’s Australian Transformation and Innovation Centre (ATiC) to provide a visual demonstration of the effectiveness of the NTT to support Network Centric Warfare operations.
Michael Tyson and Carlo Kopp
We present a Lightweight GNSS (Global Navigation Satellite System) Support Protocol (LGSP), which has been devised at Monash University. LGSP aims to comprehensively address limitations in the traditional GNSS model, such as low signal availability in urban environments, receiver initialisation delays and bandwidth restrictions, by offering an alternative secure distribution channel for GNSS data. This gives compatible receivers an alternate means for acquiring GNSS data, resulting in enhanced robustness, efficiency and availability of GNSS systems. Development of LGSP is nearing completion, and a protocol specification has been released as an Internet Draft to the IETF. This paper presents the rationale behind the development of LGSP and discusses the protocol’s architecture, message formats and definitions.
Zahir A. Daya and Daniel L. Hutt
Defence Research and Development Canada—Atlantic conducted co-operative infrared (IR) surveillance of research vessel Quest from the air in October 2006 near Halifax harbour. A Canadian Forces Military Patrol Aircraft imaged the Quest in the mid-wave IR band using the Wescam MX-20 IR camera. The Quest cruised along headings such that the sun’s azimuthal position was directly astern, perpendicular, and at 45 to the ship heading. For each of the ship-sun orientations, the aircraft executed a flight pattern that consisted of starboard and port passes that transected the Quest at nominal altitudes of 30 m and 300 m. An additional pass along the ship heading from stern to bow was made at an altitude of 150 m. Wide field-of-view IR images were collected from ranges typically exceeding 5 km with a 640 512 pixel resolution. From the digital video, we have extracted the background radiance and the total contrast signature of the Quest for the various ship-sun-pass configurations. The background sky-to-sea profiles reveal a strong increase in mid-wave IR sea radiance with steepening viewing angle. The total contrast mid-wave IR signature has an approximate power-law decay with distance for ranges between about 1–10 km. At close ranges, we qualitatively note contributions to the signature by the radiance from the wake and from reflections of the ship in the sea surface.
Shahid Baqar, Mark Richardson, and Robin Jenkin
In light of the increasing terrorist surface-to-air missile (SAM) threat to civil and military aircraft, there is a continuing need for a high-fidelity, low-cost, PC-based, infrared (IR) signature scene modelling and simulation capability which could be used for development, testing, and evaluation of IR systems. An IR signature simulator has been developed utilizing the MATLAB Virtual Reality Toolbox software with the ability to adapt to rapidly changing tactical environments. It can model the IR signature of military targets in a 3D environment with special effects.
