Understanding Key Satellite Applications

Satellites have become indispensable tools across the globe, serving a multitude of purposes. Their applications are diverse, ranging from satellite television and radio to satellite phones, live maps, surveillance, navigation, weather monitoring, and the capture of detailed satellite images. Let’s explore some of these key applications in more detail:

Satellite for Surveillance

Satellites play a crucial role in surveillance and observation of Earth’s resources and environment. This is achieved through specialized cameras and sensors specifically designed for deployment on satellites.

• Cameras: These cameras capture images of the Earth’s surface and transmit them back to ground stations.
• Infrared Sensors: These sensors detect heat sources on the Earth.

For example:

• Meteorological Satellites: Capture images of cloud formations to aid in weather forecasting.
• Geodetic Satellites: Take photographs of the Earth’s surface for mapping and surveying.
• Land and Ocean Monitoring Satellites: Help in determining the state of crops, lakes, forests, and other features.

Satellite for Navigation

One of the most well-known and useful applications of satellites is navigation, exemplified by the Global Positioning System (GPS). Let’s delve into how GPS works.

The GPS system consists of a constellation of 24 Low Earth Orbit (LEO) satellites strategically spaced around the world. Each satellite transmits a unique signal back to Earth on low microwave frequencies (1.57542 GHz and 1.2276 GHz).

Receivers on the ground pick up signals from at least four satellites simultaneously. This allows the receiver to determine its exact position, displaying its latitude, longitude, and altitude.

Satellite for Television Distribution

Traditionally, coaxial cables and microwave relay links were used to transmit TV signals. However, communication satellites have revolutionized TV signal distribution, making it incredibly easy to relay signals directly to homes via dish antennas.

Satellites transmit digitally encoded TV signals using the Ku band. Consumers only need to purchase a satellite receiver (or set-top box) along with a parabolic dish antenna to connect to their standard TV set.

Satellite Phone

The Iridium system is a prime example of satellite phone technology. It comprises 66 satellites orbiting approximately 420 miles above the Earth. These satellites communicate directly with handheld cell phones anywhere within their coverage area.

These Low Earth Orbiting Satellites (LEOs) utilize the L band and digital technology for voice and data communications.