A RANDOM THOUGHT ....

Life is a one word that can comprehend numerous meanings, meanings from the exist to exit, meanings from being one to been one. It is a thought of having something to loosing something, it is a mirror, it is an illusion, it is a sea but a desert as well.

Life itself is something that has thousands of faces and number of phases, the way a person pursue it the way it reveals itself. I personally think it is just a matter of perception that actually affects a person's life and experiences. 

Once, while doing documentary shoot at Mohatta palace, I got a chance to meet a labor working there. I asked him about his life and circumstances and I could not stopped me being inspired by his simple but precised view, he said, 

"Alhamdullillah, why should I be afraid? I am doing what I am supposed to do. My children wait for their father (him) at home my wife is simple and obedient, I have my parents and their prayers, I do not sleep hungry, who knows about another day?????? "

How many of us think and believe the same way? we are running after things even if we know that it's a wild goose chase but still we are not being able to decide where do we have to stop, what should be the priorities how should they be managed... we can't figure out the difference between pleasure and happiness. For pleasure of few moments we ruin the happiness and by pass it. 

We all should ponder and think, what are we doing? where are going ? what is actually happening around and how it should have been done ...!!!!!!!!!

What is GPS?

The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. GPS was originally intended for military applications, but in the 1980s, the government made the system available for civilian use. GPS works in any weather conditions, anywhere in the world, 24 hours a day. 

How does it works?

GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. GPS receivers take this information and use triangulation to calculate the user's exact location. Essentially, the GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. Now, with distance measurements from a few more satellites, the receiver can determine the user's position and display it on the unit's electronic map.

GPS Data simulation and calculation

A GPS receiver must be locked on to the signal of at least three satellites to calculate a 2D position (latitude and longitude) and track movement. With four or more satellites in view, the receiver can determine the user's 3D position (latitude, longitude and altitude). Once the user's position has been determined, the GPS unit can calculate other information, such as speed, bearing, track, trip distance, distance to destination, sunrise and sunset time and more.

3 satellites are being used to get 2D data

The GPS satellite system:

The 24 satellites that make up the GPS space segment are orbiting the earth about 12,000 miles above us. They are constantly moving, making two complete orbits in less than 24 hours. These satellites are travelling at speeds of roughly 7,000 miles an hour.

GPS satellites are powered by solar energy. They have backup batteries onboard to keep them running in the event of a solar eclipse, when there's no solar power. Small rocket boosters on each satellite keep them flying in the correct path.

Here are some other interesting facts about the GPS satellites (also called NAVSTAR, the official U.S. Department of Defense name for GPS):

• The first GPS satellite was launched in 1978.
• A full constellation of 24 satellites was achieved in 1994.
• Each satellite is built to last about 10 years. Replacements are constantly being built and launched into orbit.
• A GPS satellite weighs approximately 2,000 pounds and is about 17 feet across with the solar panels extended.
• Transmitter power is only 50 watts or less.

The Generic architecture of satellite

Constellation of GPS satellites

How GPS assits in aerial navigation of

Aircrafts:

GPS aircraft tracking solution needs a device embedded in the aircraft and made of a GPS sensor. It transmits in real time or not the GPS position received on board to a server on ground via a communication network. The server collects the data. Data received on ground can be recorded and/or used to display the aircraft real time position. Different kinds of communication networks are used to transmit data on ground:

• Network which is a hybrid of VHF, Satellite and HF networks.
• Transponder (Mode-S) ADS-B network.
• Satellite network (Globalstar, Thuraya, Iridium, etc).
• GSM network.

Systematic Over view of Data acquisition through satellite to obtain Aircraft cordinates

Devices installed in the aircraft are avionics components like ACARS, ADS-B or other solutions. In these cases, the receiving and transmitting antenna are usually located outside of the airframe.

When devices are not installed as avionics components they have to be completely independent from the aircraft. They are typically placed in the aircraft airframe in a location where the GPS and communication satellites are directly visible to the device, for example through the cockpit window. The output signal must also be able to go through the aircraft - most CAA require compliance with DO-160 for Audio Frequency Conducted Susceptibility and Induced Signal Susceptibility.

Authorities classify non-installed components as "Transmitting Portable Electronic Devices" and as such require them to be switched off during the critical phases of flight.

Global aerial view of data communication through GPS Satellite 

Benefits of GPS navigation aid in aviation:

There are numerous advantages of using GPS navigation in the field of aviation few of which are as follows:

•"Space-based navigation" will allow more aircraft in our airspace.

•Guarantee of 30 GPS satellites will reduce en-route and terminal spacing

•GPS will reduce fuel burn and greenhouse gas emissions. 

•More direct, time-based routings.

•GPS will enable safer operations due to position awareness.

•Reduce runway incursions.

•Provides greater situational awareness.

Smarter and better approach for path defining by using GPS satellite