Thermal sights for infantry weapons

The Thermal Revolution
March 4, 2011: Back in the 1990s, thermal sights for infantry weapons were unheard of. But now the second generation of these sights have been in combat for three years, and new models keep arriving with improvements in range, detail, zoom and reliability. Some of the latest models can be clipped on day sights, without requiring zeroing the combined sight all over again. 
It was only four years ago that the second generation of thermal weapons sights began reaching the troops. The new sights revolutionized the way troops fight at night, since "thermals" sense heat, and are effective anywhere (the old night sights depended on amplifying available light). Thermal sights are particularly popular because they also identify any warm machinery, at long distance, by detecting heat, and they can be used in caves (and other places that lack any light to amplify) as well as in situations like sandstorms and fog.
The U.S. TWS I (officially the AN/PAS-13 weapons-mounted thermal sight) has been around for a nearly a decade, but the new version addresses a long list of user complaints and suggestions. Basically, TWS II is lighter, easier to use, and easier to keep supplied with batteries. The TWS II comes in three sizes; light (for M-16 type rifles, weighs .86 kg/1.9 pounds and is good out to 550 meters), medium (for light machine-guns, weighs 1.27 kg/2.8 pounds and is good out to 1,100 meters) and heavy (for .50 caliber weapons and 40mm grenade launchers, weighs 1.73 kg/3.8 pounds and is good out to 2,200 meters). The light sight batteries last 5-25 hours, while the heavier models are good for 6.5-18 hours.
Compared to TWS I, the new versions are about a third lighter, and use standard AA batteries. This was something the troops were emphatic about. TWS I used special batteries, which, too often, the users could not get replacements for. But you can always get AAs. Even during combat, troops have found local Iraqi or Afghan shops selling AAs, and were able to keep their electronic gear going as a result.
Over 20,000 TWS II sights have been produced so far. And everyone wants one. The army alone expects to eventually spend over $2 billion on new thermal sights, and it will be another three years before production catches up with demand for helmet and weapons mounted thermals
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AN/APG-71 fire-control radar for the F-14D (United States), Airborne radar systems

Description (From Jane's Avionics)
AN/APG-71, in part derived from the AN/APG-70 FCR in the Boeing F-15E Strike Eagle, replaced the AN/AWG-9 radar originally fitted to F-14A/B aircraft.Compared with the AWG-9, the APG-71 provided for better overland performance, expanded velocity search capability, a larger target engagement zone, a raid assessment mode and programmable electronic countermeasures and clutter control features.The APG-71 introduced greatly improved ECM performance, acknowledging the new and vastly more sophisticated jamming technologies that appeared since design of the F-14 was frozen. New modes included medium-PRF all-aspect capability, monopulse angle tracking, digital scan control, target identification and raid assessment while the number of Line Replaceable Units (LRUs) reduced from 26 to 14. The system also employed elements developed by Hughes for the AN/APG-70; for example the APG-71 signal processor was 86 per cent common (in modules) with that in the APG-70. The AWG-9's transmitter, power supply and aft cockpit tactical information display were retained for the APG-71.The APG-71 also incorporated Non-Co-operative Target Recognition (NCTR), by which radar contacts may be identified as friendly or hostile, at beyond visual range, through close examination of the raw radar returns at high resolution; this technique alleviates problems with deficiencies and ambiguities in IFF equipment.The APG-71's antenna retained the gimbal system of the AWG-9 and added a new array with low sidelobes and a guard channel to eliminate sidelobe penetration of ground clutter and electronic warfare interference. The APG-71 also provided an improved radar master oscillator which significantly increased the number of radar channels and provided frequency-agile

From Wikipedia, the free encyclopedia

The AN/AWG-9 and AN/APG-71 radars are all-weather, multi-mode X-Band pulse doppler radar systems designed for the F-14 Tomcat. It is a very long-range air-to-air system with the capability of guiding several AIM-54 Phoenix or AIM-120 AMRAAMmissiles at the same time using its track while scan mode. The primary difference between the AWG-9 and APG-71 is the replacement of the former's analog electronics with all-digital units. Both the AWG-9 and APG-71 were designed and manufactured by Hughes Aircraft; contractor support is now being provided byRaytheon.

The AN/AWG-9 offers a variety of air-to-air modes including long-range continuous wave velocity search, range-while-search at shorter ranges, and the first use of an airborne track-while-scan mode with the ability to track up to 24 airborne targets, display 18 of them on the cockpit displays, and launch against 6 of them at the same time. This function was originally designed to allow the Tomcat to shoot down formations of bombers at long range.

The F-14 AN/AAS-42 IRST (Infrared Search and Track)

The F-14 AN/AAS-42 IRST (Infrared Search and Track) is a passive long-wave infrared sensor system that searches for and detects heat sources within its field of view. Operating in six discrete modes, the AN/AAS-42 provides the aircraft mission computer track file data on all targets while simultaneously providing infrared imagery to the cockpit display. The AN/AAS-42 gives the aircrew unprecedented on-board situational awareness while significantly enhancing the engagement range of modern high-performance weapons such as the AIM-120

aerosols

Schematic diagram of the many interactions of aerosols in the environment and with clouds.

Focus Area Lead - Steve Ghan

The role of aerosols in climate forcing is a critical factor in assessment and prediction of climate changes, as well as in advancing climate modeling frameworks. Aerosol forcing has two major components, direct and indirect. Direct effects of aerosols are the influence of the aerosols on the planet's radiation balance by the scattering of solar radiation, which result in the cooling of the Earth's surface. Aerosols can also have an indirect effect on climate, based on the ways in which aerosols interact with surrounding clouds. Direct effects of aerosols on the climate system are much better understood and quantified than the indirect effects.