Working of GPS

Global Positioning System or GPS is a system that is commonly used nowadays to get from one place to another, creating a hassle-free experience. It has a variety of other uses besides navigation too, like

• Location- finding the position of a place or subject

• Mapping- Creating world maps

• Timing- availability of precise time measurements

• Tracking- Monitoring the movement of an object or a person

The applications of these functions are far and plentiful; it plays a major role in emergency response during disasters- mapping, and predicting weather patterns, in reducing response times for first responders. It also plays a crucial role in military, naval operations, maritime and land transportation services, health and fitness apps and even in entertainment, for example in games using augmented reality like Pokemon Go.

We generally open up our phones, or the navigation systems on our cars, put in a location and set off based on the route shown to us by the map. But have you ever wondered how the gadgets we use know this route? How are they more reliable as navigators than the signs on the roads?

Well, it’s story time people.

The GPS was introduced by the U.S.A and it has three major elements-

• Space Segments- They refer to the 32 GPS satellites that orbit the earth collecting and transmitting information in the form of signals to the earth. The radio transmitters on them send unique signals to the GPS receivers.
• Control Segments- They are the monitoring stations on earth which helps in tracking, operating and checking the overall welfare of the satellites and its transmissions. The data collected from the stations are uplinked to the satellites in order to transmit it back to the users.
• User Segments- They include any GPS receivers that are used both in the military and civilian communities. GPS has been integrated into flights, submarines, tanks, helicopters and other equipment. Along with this, they are also seen in aiding aircrafts and ships with navigation, used in delivery monitoring systems to track packages. Mostly commonly it is seen in in-car navigation systems, in smartphones.

The How Behind GPS- Trilateration

• The satellites that roam the earth send information about its current locations and time to the monitoring stations at fixed times, which is then transmitted to the receiver devices as radio signals. Their locations are determined by computing the difference between the time signals are sent and the time it is received, thus finding the satellites closest to the location. The timings are extremely precise due to the usage of atomic clocks.
• The signals sent by the satellites also encode the timings within them enabling the receivers to continuously determine the signal broadcast timing. Signals transmitted from the satellites also contain accurate data that is required to compute their respective locations for determining the exact position.
• The receiver device determines the time difference between the reception of the signals and its broadcast timing to calculate the distance or range from the receiving end to the satellites.
• In order to calculate the location accurately the GPS requires signals from a minimum of 3 satellites based on which it is pinpointed. With a 4 satellite the need for an atomic clock can be avoided. Each satellite creates a spherical area and when all the spheres overlap, it provides the position of the place on earth’s surface.
• The four satellites can work in tandem to compute the latitude, longitude, altitude and time and transmit it to the receiver. This entire process is termed as trilateration.
• The accuracy of GPS is dependent on a variety of factors, like the number of satellites available, atmospheric conditions, physical obstructions like buildings, mountains, trees etc.

With advancements in every field rolling in matter of minutes and seconds, it is safe to say that GPS will keep getting better and better in terms of navigation accuracy, speed and still have a widening arena of usage. Navigating through the world gets easier by the day with newer inventions that make it possible. GPS is one such invention with vast potential and usage on an everyday basis. We can go a long way with a little help and guidance, or GPS, so set a location and have a fun, safe ride!