The use of visual cues for vehicle control and navigation

At least three levels of control are required to operate most vehicles: (1) inner-loop control to counteract the momentary effects of disturbances on vehicle position; (2) intermittent maneuvers to avoid obstacles, and (3) outer-loop control to maintain a planned route. Operators monitor dynamic optical relationships in their immediate surroundings to estimate momentary changes in forward, lateral, and vertical position, rates of change in speed and direction of motion, and distance from obstacles. The process of searching the external scene to find landmarks (for navigation) is intermittent and deliberate, while monitoring and responding to subtle changes in the visual scene (for vehicle control) is relatively continuous and 'automatic'. However, since operators may perform both tasks simultaneously, the dynamic optical cues available for a vehicle control task may be determined by the operator's direction of gaze for wayfinding. An attempt to relate the visual processes involved in vehicle control and wayfinding is presented. The frames of reference and information used by different operators (e.g., automobile drivers, airline pilots, and helicopter pilots) are reviewed with particular emphasis on the special problems encountered by helicopter pilots flying nap of the earth (NOE). The goal of this overview is to describe the context within which different vehicle control tasks are performed and to suggest ways in which the use of visual cues for geographical orientation might influence visually guided control activities

Orientation with a Viking sun-compass, a shadow-stick, and two calcite sunstones under various weather conditions.

It is widely accepted that Vikings used sun-compasses to derive true directions from the cast shadow of a gnomon. It has been hypothesized that when a cast shadow was not formed, Viking navigators relied on crude skylight polarimetry with the aid of dichroic or birefringent crystals, called "sunstones." We demonstrate here that a simple tool, that we call "shadow-stick," could have allowed orientation by a sun-compass with satisfying accuracy when shadows were not formed, but the sun position could have reliably been estimated. In field tests, we performed orientation trials with a set composed of a sun-compass, two calcite sunstones, and a shadow-stick. We show here that such a set could have been an effective orientation tool for Vikings only when clear, blue patches of the sky were visible

Oceanographic and underwater acoustics research conducted during the period 1 May 1961-31 October 1961

Research during this six month period was performed during cruises of the CHAIN to the Romanche Trench, to the Puerto Rico Trench, and to the Mediterranean Sea, and during a cruise of the BEAR to the Gulf of Maine. New instrumentation aboard the CHAIN included the 12, 000 joule Boomer and a 25, 000 joule Sparker for continuous Seismic reflection profiles and other research in hydroacoustics. A semiautomatic data recording system for shipboard use was in.stalled and operated by IBM and, to facilitate launching and retrieving deep gear, a closed circuit television system was used . Also the navigational system, GEON, was installed and tested. Prior to the cruises of the summer and fall redesign and refinement of the instrumentation and equipment entailed overhaul of the thermistor chain and contouring temperature recorder, modification of the heat probe for thermal gradient measurements to lessen lowering time, and improvement of the inverted echo-sounding equipment. Research at sea included collecting samples of rock and sediment and photographing the ocean floor in support of research into the structure and dynamics of the Romanche and Puerto Rico Trenches and the Mid-Atlantic Ridge , observing internal waves in the North Atlantic studying water circulation in the Mediterranean, the dynamics of flow through the Strait of Gibraltar (concentrating this year on internal waves there), observing the behavior and measuring the sound scattering properties of deep scattering layers in the Mediterranean, measuring heat flow from the inner Earth across the Mid-Atlantic Ridge and in the western Mediterranean, and studying the relationship between sound transmission and the physical properties of the water and sea floor in the eastern Mediterranean. At Woods Hole various analysis programs progressed. Several of these used programs of digital computing which have been prepared lately at Woods Hole. The precision time source for remote control reported earlier was improved and tested ashore. A tape recording system for Scuba divers was devised and tested satisfactorily in thirty feet of water.Undersea Warfare Branch Office of Naval Research Contracts Nonr-1367(00)NR 261-102 and Nonr-2129(00)NR 261-10

Conceptual design for Mobile Geological Laboratory position and heading fix system

Conceptual design of position fixing system for Mobile Geological Laboratory in Lunar Mobile Laboratory simulatio

Urban Planning in the First Unfortified Spanish Colonial Town: The Orientation of the Historic Churches of San Cristóbal de La Laguna

The city of San Cristóbal de La Laguna in the Canary Island of Tenerife (Spain) is of exceptional value as the first unfortified colonial city to follow regular plan - a grid, outlined by straight streets that form squares - in the overseas European expansion. It constitutes a historical example of the so-called "Town of Peace", the archetype of a city-republic in a new land that employed its own natural boundaries to delimit and defend itself. Founded in 1496, the historical centre of the old city was declared a World Heritage Site by UNESCO in 1999 (UNESCO World Heritage Committee, n.d.). We analyse the exact spatial orientation of 21 historic Christian churches currently existing in the old part of La Laguna, which we take as a good indicator of the original layout of the urban lattice. We find a clear orientation pattern that, if correlated with the rising or setting Sun, singles out an absolute-value astronomical declination slightly below 20°, which, within the margin of error of our study, might be associated with the 25th July feast day of San Cristóbal de Licia, the saint to whom the town was originally dedicated. We also discuss at some length some recent proposals which invoke somewhat far-fetched hypotheses for the planimetry of the old city and conclude with some comments on one of its outstanding features, namely its Latin-cross structure, which is apparent in the combined layout of some of its most emblematic churches.Fil: Gangui, Alejandro. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Belmonte, Juan Antonio. Instituto de Astrofísica de Canarias; Españ

Study of celestial/inertial test facility Final report

Test facility and equipment for evaluation of optical sensors employed in celestial navigation and guidance system

Displays, instruments, and the multi-dimensional world of cartography

Cartographers are creators and purveyors of maps. Maps are representations of space, geographical images of the environment. Maps organize spatial information for convenience, particularly for use in performing tasks which involve the environment. There are many different kinds of maps, and there are as many different uses of maps as there are spatial problems to be solved. Maps and the display instrument dichotomy are examined. Also examined are the categories of map use along with the characteristics of maps

Design study of a low cost civil aviation GPS receiver system

A low cost Navstar receiver system for civil aviation applications was defined. User objectives and constraints were established. Alternative navigation processing design trades were evaluated. Receiver hardware was synthesized by comparing technology projections with various candidate system designs. A control display unit design was recommended as the result of field test experience with Phase I GPS sets and a review of special human factors for general aviation users. Areas requiring technology development to ensure a low cost Navstar Set in the 1985 timeframe were identified