Integrated Navigation System: Not a Sum of Its Parts

Similar to the evolutionary process for living organisms, marine navigation systems are becoming increasingly complex and sophisticated. Both by design and function, shipboard and shore-based navigation systems are no longer individual equipment components operating independently. Instead, the trend is toward integration, data fusion and synergy. One example of this are new Performance Standards being considered by IMO to achieve a “harmonized” presentation of all navigation-related information on the display of an integrated navigation system (INS). Unlike a dedicated display for ECDIS or radar, the new INS displays will be a task-oriented composite presentations that enable the mariner to configure the display for an operational situation by selecting specific chart, radar, radar plotting aids (ARPA) and AIS information that is required for the task-at-hand. This paper gives a brief overview of the trend toward the development of INS. In addition to a brief summary of IMO performance standards for navigation equipment/systems, specific mention is made about a BSH (Germany) report on the “Functional Scope and Model of INS.” A discussion is provided about the challenges of providing navigation safety information that goes beyond traditional boundaries of products and services. Currently, many agencies continue to produce individual products and services on a component basis. Hydrographic offices grapple with trying to provide multiple products and services for paper charts, raster navigational charts (RNCs) and electronic navigational charts (ENCs) while a same time, Coast Guard and Maritime Safety agencies focus on improving Aids-to-Navigation (AtoN), Vessel Traffic Services (VTS), AIS networks -- and more recently, port security. In some respects, the continued concentration on separate products and services represents an organizational reluctance to change. This in turn, results in a fragmented, sub-optimal approach to the safety-of-navigation caused by the inability to provide mariners with “seamless” information at reasonable cost. In particular, hydrographic offices must be willing to recognize that chart information can no longer be considered to be separate, individual products. When it comes to the provision and use of chart-related information for use in an INS, the focus needs to shift to what information is actually desired, how it will be provided, what other information it will be used with, and whether it is truly up-todate

Ground support, data analysis and associated research and development for the rocket grenade experiment Final report, 16 Aug. 1961 - 31 May 1965

Ground support, noise level measurements, data analyses, and equipment developed for sound ranging arrays in rocket grenade experimen

The preparation of metallic boron

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1940.Includes bibliographical references (leaf 31).by James F. Levis.B.S

Aeroheating Measurements of BOLT Aerodynamic Fairings and Transition Module

The Air Force Office of Scientific Research (AFOSR) has sponsored the Boundary Layer Transition (BOLT) Experiments to investigate hypersonic boundary layer transition on a low-curvature, concave surface with swept leading edges. This paper presents aeroheating measurements on a subscale model of the BOLT Flight Geometry, aerodynamic fairings, and Transition Module (TSM) in the NASA Langley 20-Inch Mach 6 Air Tunnel. The purpose of the test was to investigate and identify any areas of localized heating on the TSM for inclusion in the BOLT Critical Design Review (CDR). Surface heating distributions were measured using global phosphor thermography, and data were obtained for a range of model attitudes and free stream Reynolds numbers. Measurements showed low heating on the fairings and TSM. Additional analysis was completed after the CDR to compare heating on the TSM for the nominal BOLT vehicle reentry angle-of-attack with heating on the TSM for possible reentry angle-of-attack excursions. The results of this analysis were used in conjunction with thermal analyses from Johns Hopkins Applied Physics Lab (JHU/APL) and the Air Force Research Laboratory (AFRL) to assess the need for thermal protection on the flight vehicle TSM

On Measuring the Infrared Luminosity of Distant Galaxies with the Space Infrared Telescope Facility

The Space Infrared Telescope Facility (SIRTF) will revolutionize the study of dust-obscured star formation in distant galaxies. Although deep images from the Multiband Imaging Photometer for SIRTF (MIPS) will provide coverage at 24, 70, and 160 micron, the bulk of MIPS-detected objects may only have accurate photometry in the shorter wavelength bands due to the confusion noise. Therefore, we have explored the potential for constraining the total infrared (IR) fluxes of distant galaxies with solely the 24 micron flux density, and for the combination of 24 micron and 70 micron data. We also discuss the inherent systematic uncertainties in making these transitions. Under the assumption that distant star-forming galaxies have IR spectral energy distributions (SEDs) that are represented somewhere in the local Universe, the 24 micron data (plus optical and X-ray data to allow redshift estimation and AGN rejection) constrains the total IR luminosity to within a factor of 2.5 for galaxies with 0.4 < z < 1.6. Incorporating the 70 micron data substantially improves this constraint by a factor < 6. Lastly, we argue that if the shape of the IR SED is known (or well constrained; e.g., because of high IR luminosity, or low ultraviolet/IR flux ratio), then the IR luminosity can be estimated with more certainty.Comment: 4 pages, 3 figures (2 in color). Accepted for Publication in the Astrophysical Journal Letters, 2002 Nov

The Stellar Populations and Evolution of Lyman Break Galaxies

Using deep near-IR and optical observations of the HDF-N from the HST NICMOS and WFPC2 and from the ground, we examine the spectral energy distributions (SEDs) of Lyman break galaxies (LBGs) at 2.0 < z < 3.5. The UV-to-optical rest-frame SEDs of the galaxies are much bluer than those of present-day spiral and elliptical galaxies, and are generally similar to those of local starburst galaxies with modest amounts of reddening. We use stellar population synthesis models to study the properties of the stars that dominate the light from LBGs. Under the assumption that the star-formation rate is continuous or decreasing with time, the best-fitting models provide a lower bound on the LBG mass estimates. LBGs with ``L*'' UV luminosities are estimated to have minimum stellar masses ~ 10^10 solar masses, or roughly 1/10th that of a present-day L* galaxy. By considering the effects of a second component of maximally-old stars, we set an upper bound on the stellar masses that is ~ 3-8 times the minimum estimate. We find only loose constraints on the individual galaxy ages, extinction, metallicities, initial mass functions, and prior star-formation histories. We find no galaxies whose SEDs are consistent with young (< 10^8 yr), dust-free objects, which suggests that LBGs are not dominated by ``first generation'' stars, and that such objects are rare at these redshifts. We also find that the typical ages for the observed star-formation events are significantly younger than the time interval covered by this redshift range (~ 1.5 Gyr). From this, and from the relative absence of candidates for quiescent, non-star-forming galaxies at these redshifts in the NICMOS data, we suggest that star formation in LBGs may be recurrent, with short duty cycles and a timescale between star-formation events of < 1 Gyr. [Abridged]Comment: LaTeX, 37 pages, 21 figures. Accepted for publication in the Astrophysical Journa