GPS aided Geo Augmented Navigation system (GAGAN):

• A satellite-based facility aimed at enhancing safety and efficiency of aircraft operations
• Expected to be installed in all airports in the country by June 2013.
• Joint venture b/w AAI and ISRO.
• Will improve air traffic management via timely information on aircraft movement.
• Once it is implemented, India would be the 4^th nation in the world to have a satellite-based navigation system after USA, Japan and European Consortium.
• Human intervention will be minimized or eliminated for navigational leading both at Air Traffic Control room and aircraft cockpit, by virtue of this system.
• The system would raise safety and effectiveness of aircraft operations via better situational cognizance and safety alerts/tools for the Air Traffic Controllers.
• Under ISRO's guidance, AAI had installed ground reference stations in 15 strategic locations all over India and all airports would be networked via them.
• The national GAGAN Centre would be located in Bangalore.
• Apart from air navigation applications, GAGAN would also be helpful to other service providers like the Indian Railways, Survey of India, Geological Survey of India, and Archaeological Survey of India etc. And even to the Navy and Indian Coast Guard.

{Reference: Double ITCZs - Journal of Geophysical Research, Vol. 106 No. D11, by Chidong Zhang}

The ocean-atmospheric phenomenon called Double Inter Tropical Convergence Zone (DITCZ) investigated by the Researchers at the National Institute of Oceanography, Goa, have investigated over the Western Indian Ocean, for its meteorological characteristics.

What is DITCZ?

• A Double Inter Tropical Convergence Zone is a phenomenon featured with two ITCZs, one at each side of the equator.
• About 10 degrees north or south of the equator there forms a region of convective activity which is called the Inter Tropical Convergence Zone (ITCZ). Sometimes, on the opposite side of the equator, another ITCZ forms which is short-lived (November-December) in the western Indian Ocean and this phenomenon is called Double Inter Tropical Convergence Zone (DITCZ).

When and Where are DITCZs found?

• The most identifiable double ITCZ is found over the eastern Pacific during boreal spring, mainly in March and April. Weak signals of a double ITCZ exist over the Indian Ocean during November, but only infrequently. Over the western and central Pacific, signatures of a double ITCZ can often be found, but mostly during June through September. No double TTCZ is found over the Atlantic Ocean.
• The existence of double ITCZs is nothing new. Those who follow closely tropical weather and climate have long recognized that a double ITCZ occurs frequently over the eastern Pacific during boreal spring.
• On the basis of the limited observations, it is proposed that double ITCZs in the Pacific are more causally related to surface thermal conditions than atmospheric internal dynamics alone.

Why is this Study important?

• The study derives significance as former studies found weak signals of the DITCZs over the Indian Ocean in November. Yet, the temporal evolution of these in the Indian Ocean could not be assured, primarily because of dearth of data.
• Double ITCZs are significant climatological features of the tropics because of their repeating occurrence at certain longitudes and during certain seasons. Double ETCZs deserve more research attention than they have received, especially in the context of interpreting climate simulations of GCMs and theoretically understanding the ITCZ.

How did the researchers investigate?

Read on...

The Government has instructed all cell phone manufacturers to include radiation tags in mobile handsets to display Specific Absorption Rate, SAR value by the first of September 2012. All the indigenous manufactures have been instructed to make necessary changes in the design, software and packaging in compliance with these instructions within the stipulated time.

A radiation tag is a device embedded within a cell phone for checking radiation emitting from it.

China successfully launched 2 more satellites for its proposed Beidou Global Navigation and Positioning Network being built to counter the US Global Position System (GPS).
With these two satellites, China has so far launched 13 satellites to form part of the Beidou system.

The Beidou-2 satellites, launched from the Xichang Satellite Launch Center in the southwestern province of Sichuan, was boosted by a Long March-3B carrier rocket and has entered the scheduled orbit. It is the first time that China has launched two navigation satellites with one rocket, and the two satellites will help to improve the accuracy of the Beidou, or Compass system.

What is BeiDou Navigation System?

• The BeiDou Navigation System or BeiDou (Compass) Navigation Satellite System - a project by China to develop an independent satellite navigation system.
• Refers to either one or both generations of the Chinese navigation system.
• BeiDou Global Navigation and Positioning Network being built to counter the US Global Position System (GPS).
• China: BeiDou-1, BeiDou-2; Europe: Galileo Systems; Russian: GLONASS ; US: GPS
• BeiDou-1: The first BeiDou system (officially called BeiDou Satellite Navigation Experimental System, or known as BeiDou-1) - consists of 3 satellites and has limited coverage and applications. Offering navigation services mainly for customers in China and from neighbouring regions since 2000.
• Difference with others: Unlike the American GPS, Russian GLONASS, and European Galileo systems, which use medium Earth orbit satellites, BeiDou-1 uses satellites in geostationary orbit. This means that the system does not require a large constellation of satellites, but it also limits the coverage to areas on Earth where the satellites are visible.
• Compass or BeiDou-2: The 2nd generation of the system, known as Compass or BeiDou-2, which will be a global satellite navigation system consisting of 35 satellites, is still under construction. It became operational with coverage of China in December 2011 with 10 satellites in use. It is planned to offer services to customers in Asia-Pacific region by 2012 and the global system should be finished by 2020.

The PM Dr. Manmohan Singh heralded the successful launch of PSLV carrying RISAT-1 and preened the scientists linked with the project. India's first indigenous all-weather Radar Imaging Satellite (RISAT-1), whose images will facilitate agriculture and disaster management, was launched successfully on board the PSLV-C19 from Sriharikota in the early hours on April 26, 2012. It was the 20^th consecutive successful launch of the PSLV, thus a vital milestone in India's space programme and it demonstrates ISRO’s mastery of the complex launch vehicle technology.

More on RISAT-1:

http://www.gktoday.in/risat-1-all-set-for-launch-at-sriharikota/

http://www.gktoday.in/unique-radar-imaging-satellite-or-risat-1-ready-for-launch/