What is a GPS? How Does it Works

The Global Positioning System (GPS) is a satellite navigation system that provides precise location and time data in all weather conditions, anywhere on earth. For GPS to work there should be an unobstructed line of sight to 4 or more GPS satellites. GPS provides capabilities to military, civil, and commercial users around the globe.
GPS


Components of a GPS

 

A GPS has three segments i.e space, control, and user segments as given below:


 

Space Segment (GPS Satellites):

 

  • This segment has 24 satellites deployed on six orbits around the earth at an altitude of 20,000 Km. These satellites revolve around the earth at intervals of 12 hours.

 

Control Segment (Ground Control Stations):

 

  • Ground control stations have 5 unmanned monitor stations and 1 Master control station which constantly monitor, control and maintain satellite orbits. Their work is to make sure that deviations of satellites from orbits are within the tolerance level.

 

User Segment (GPS Receivers):

 

  • This segment has civilian or military users. The number of users of GPS is limitless.


Working of GPS device


The orbits of the satellites are adjusted in such a manner that a GPS receiver on the earth can receive signals from at least 4 satellites at any given time. A position on earth can be calculated by measuring the distances to 3 satellites simultaneously.


GPS Working and application

The satellites used to find the current position are equipped with atomic clocks, allowing precise measurement of time. The signals sent by satellite contain encrypted data on the exact moment of transmission. A receiver on the earth contains a memory with the coordinates of each satellite. The time difference between sending and receiving the signal can be calculated by (s=c*t).

  • In the space, if you know your distance from the satellite, you are somewhere on a sphere of that radius.
  • If two satellite distances are known, the only locations that are at the right distance from both satellites form a circle where the two surfaces intersect.
  • If a third satellite distance is known, you must be on its sphere as well as the intersection circle of the first two. Now there are two positions say A and B that can lie on the three spheres at the same time. 
  • The earth is a fourth sphere having position A in space and position B on the earth.


The time measured by clocks in GPS receivers is not precise and accurate as the time measured by atomic clocks in GPS satellites. Hence, a 4th satellite is used to minimize the margin of error in position accuracy. Of course, if the measurement involves a constant unknown error, we need to understand four unknown terms in 3-D space:
  • Longitude (X)
  • Height (Z)
  • Latitude (Y)
  • Time Error (dT)


Uses of a GPS in Daily Life


Global positioning system has many daily uses:


5 Best Uses Of GPS Tracking Devices

  • It is used for navigation on water, land, and air.
  • It helps in map designing of a place.
  • It is used in self-driving automobiles.
  • The speed of an object can be measured by this technology.
  • Change in position of glaciers, mountain heights can be located easily.
  • It helps in maintaining standard time over the world.
  • It is used for tracking animals, birds, and insects by attaching a GPS device on their bodies.
  • It helps in controlling air traffic.
  • It helps visually impaired people in locating their destinations.

Popular Posts

Conducting Polymers: Definition, Examples, Properties and Applications

Image
What are Conducting Polymers? As the name suggests organic polymers that conduct electricity are known as conducting polymers. They are also known as intrinsically conducting polymers (ICPs) and they have alternating single and double bonds along the polymer backbone (conjugated bonds) or that are composed of aromatic rings such as Phenylene, naphthalene, anthracene, pyrrole, and thiophene which are connected through carbon-carbon single bonds. Examples: Polyacetylene, Polypyrrole, Polyaniline, etc What is the reason behind conducting nature of these polymers? Conducting polymers comes in two forms that are doped conducting polymers and non-doped conducting polymers. The conductivity of non-doped conjugated polymers is due to the existence of a conductivity band similar to a metal. In a conjugated polymer, three of the four valence electrons form strong sigma bonds through sp² hybridization where electrons are strongly localized. The remaining unpaired electron of each carbon atom re
Read more

Crime Scene: Definition, Types and Characteristics

Image
What is a Crime Scene ? A place where the crime is committed or where the maximum physical evidence related to crime is found is known as a crime scene. A crime scene is a starting point of the investigation which provides information about the suspect and the victim. This helps to reconstruct the crime and fast resolution of the case. It is noted that the crime scene is not limited to a single place but may extend to a wider area depending upon the nature of the crime committed. For example, In a murder case where murder is done at one place and the body is disposed on another place. In this case, we have two crime scenes that give information about the crime. Types of Crime Scene Based on evidence found on the crime scene: 1. Primary Crime Scene The crime scene where the actual crime occurred or where more usable pieces of evidence were found is known as the primary crime scene. For example, A murder scene, theft, assault, etc. 2. Secondary Crime Scene The crime scene which is some
Read more

Raman Spectroscopy: Principle, Instrumentation and Applications

Image
What is Raman Spectroscopy? Raman spectroscopy was given by an Indian Physicist Sir C.V Raman , which is based on inelastic scattering of monochromatic light with the sample. The resulting light will have a different frequency than incident light due to this inelastic scattering.  This technique is widely used to analyze vibrational, rotational, and other low-frequency interactions in the molecule. This significantly helps in the elucidation of molecular structure, identifying functional groups, etc. Principle of Raman Spectroscopy Raman spectroscopy is based on the inelastic scattering of electromagnetic radiation with the molecule. We have two types of scattering that are elastic and inelastic scattering.  Elastic scattering obeys the Rayleigh law that states that there will be no loss of energy and momentum of the incidence radiation and scattered radiation. That's why this scattering is also known as Rayleigh scattering. Whereas, there will be some conditions (1 in million
Read more