Design of an image radiation monitor for ILS glide slope

The design of a monitor that measures changes in ground reflected image radiation is presented. This monitor is shown to be theoretically capable of determining the effects of snow cover and standing water in the vicinity of an Instrument Landing System (ILS) image-type glide slope, thereby reducing the number and length of outages. A discussion of errors and calibration are presented, along with an example of a practical design     

Status of the Stratospheric Observatory for Infrared Astronomy (SOFIA)

The Stratospheric Observatory for Infrared Astronomy (SOFIA), a joint US/German project, is a 2.5-m infrared airborne telescope carried by a Boeing 747-SP that flies in the stratosphere at altitudes as high as 45,000 ft (13.72 km). This facility is capable of observing from 0.3 μm to 1.6 mm with an average transmission greater than 80% averaged over all wavelengths. SOFIA will be staged out of the NASA Dryden Flight Research Center aircraft operations facility at Palmdale, CA. The SOFIA Science Mission Operations (SMO) will be located at NASA Ames Research Center, Moffett Field, CA. First science flights began in 2010 and a full operations schedule of up to one hundred 8 to 10 hour-long flights per year will be reached by 2014. The observatory is expected to operate until the mid-2030s. SOFIA’s initial complement of seven focal plane instruments includes broadband imagers, moderate-resolution spectrographs that will resolve broad features due to dust and large molecules, and high-resolution spectrometers capable of studying the kinematics of atomic and molecular gas at sub-km/s resolution. We describe the SOFIA facility and outline the opportunities for observations by the general scientific community and for future instrumentation development. The operational characteristics of the SOFIA first-generation instruments are summarized. The status of the flight test program is discussed and we show First Light images obtained at wavelengths from 5.4 to 37 μm with the FORCAST imaging camera. Additional information about SOFIA is available at http://www.sofia.usra.edu and http://www.sofia.usra.edu/Science/docs/SofiaScienceVision051809-1.pdf.     

Evaluation of image-type glide slope performance in the presence ofsnow cover

A formulation for the effects that the ground-reflected signal has on the far-field performance of image-type glide slope is developed using geometrical optics. The effects of snow cover are then related to the formulation and analyzed. Results indicate that it is possible for certain types of dry snow to cause glide slope system performance to exceed U.S. Flight Inspection Manual (USFIM) tolerances at depths below existing Federal Aviation Administration (FAA) plowing criteria