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How Does GPS Actually Work?

How Does GPS Actually Work?

Practically everyone uses GPS at some point during the day. Even during your personal time, you might use GPS to get efficient driving directions, track your exercise, or find stores and restaurants in your area.

Businesses also use GPS for a wide range of applications that include:

  • Improving supply chain resilience
  • Finding items in warehouses
  • Tracking employee performance and safety (especially when they drive company vehicles)

GPS has applications in industries from home health care to law enforcement. If you manage a business, reliable GPS units can probably improve some aspect of your operations.

Although people rely on GPS daily, not everyone understands what makes GPS work. It's such a common technology that you might never think about what happens "behind the scenes" to make your GPS units effective.

The following post explains how GPS satellites and units work together to make the technology successful.

The Basics of GPS

GPS technology relies on three parts:

  • Satellites
  • Ground stations
  • Receivers

The satellites constantly send signals that describe their locations. Ground stations track satellites to ensure they know their true locations instead of transmitting inaccurate information. Receivers include devices like smartphones and stand-alone GPS units like the LandAirSea 54.

Satellites in the Global Positioning System (GPS)

GPS relies on a system of more than 30 low-orbit satellites currently managed by the US Space Force. The satellites contain atomic clocks that maintain extremely accurate time. Satellites constantly transmit signals that contain information about their locations and when the signals were sent.

Interestingly, GPS is just one group of satellites within the Global Navigation Satellite System (GNSS). The other parts of GNSS include:

  • Galileo, managed by the European Union
  • BeiDou Navigation Satellite System, managed by China
  • Global Navigation Satellite System (GLONASS), managed by Russia

Eventually, India plans to make its Indian Regional Navigation Satellite System (IRNSS) part of the global system.

Additionally, Japan's Quasi-Zenith Satellite System (QZSS) helps enhance GPS accuracy for receivers in Asia-Oceania. Japan plans to have seven QZSS satellites in orbit by the end of 2023.

The Role Ground Stations Play in How GPS Works

The Ground-Based Augmentation System helps ensure that satellites communicate accurate information to receivers.

Although satellites contain highly reliable clocks, they can become slightly inaccurate. Over time, these small inaccuracies could compound into misinformation that would make GPS and similar systems more dangerous than useful.

When satellites come within range of a ground station, the station sends a radio signal that bounces off the satellite and returns to the station. The ground station can then compare its measurement with the satellite's signal. If ground stations find differences in the signals, they can correct the satellite to ensure it communicates accurate information to receivers.

Most ground stations are located near airports, which lets them update inaccurate information and maintain safety for aircraft as they land, leave, and circle the area. However, there are other ground stations that perform this service, especially in low-population areas without large airports.

How GPS Units Operate

GPS units use satellite signals to calculate locations and movements. Some GPS units only describe locations in two dimensions (latitude and longitude). Calculating 2D locations requires signals from three satellites.

More sophisticated GPS units can calculate locations in three dimensions (latitude, longitude, and altitude). This requires signals from at least four satellites.

Most GPS units can calculate time regardless of whether they use 2D or 3D locations. However, you can expect more accurate estimates with 3D locations because they account for changes in altitude. Instead of using a flat, two-dimensional map, you get a three-dimensional representation. You will need the third dimension when using GPS units with aircraft, large warehouses, and any other use case that requires knowing an object's height.

Companies often make GPS units that perform highly specific functions, such as calculating:

  • Speed
  • Trip distance
  • The remaining distance to a destination
  • Location with an accuracy of up to about 6 feet

Software Plays a Critical Role in GPS Services

Government agencies oversee the accuracy of satellites and ground receivers, so you don't need to think much about how those parts of GPS operate. Unless a major disaster occurs, you can count on them to work.

However, you do need to compare GPS units to choose options that suit your needs. A stand-alone GPS unit typically offers better accuracy than a smartphone app. Your smartphone must dedicate processing power to several tasks simultaneously. A stand-alone unit only needs to address the requirements of GPS.

Software also plays a critical role in the quality of GPS services. Software determines what features you can expect from your GPS unit. For example, LAS's Silvercloud app lets you:

  • View all the devices you manage
  • Activate and manage the GPS units you own
  • View location histories of your GPS units
  • Create fences that send alerts when a GPS unit crosses a boundary
  • Share locations with authorized users
  • Receive alerts when employees drive recklessly or spend excess time idle
  • Turn a GPS unit's lights on or off (an important feature when you want to track an item or vehicle covertly)
  • View all your active devices on a map

Silvercloud works on Android and iOS devices. You can also access the cloud-based app via any web browser, making it easy for you to manage units and employees from any location with an internet connection.

All LAS GPS units are compatible with Silvercloud, so you can choose the device that matches your needs best. Topsellers include:

  • LAS 54, an affordable, discrete GPS unit tough enough to survive practically any environment
  • LAS Sync, which connects directly to any vehicle's OBD-II port
  • LAS Overdrive, a compact unit with an extended battery life

Find the Right GPS Unit for Your Needs

LAS designs and manufactures all of our products in the United States to ensure the highest levels of accuracy and longevity. If you're not sure which GPS unit matches your needs, feel free to reach out to ian.conley@landairsea.com. We'll review how you plan to use your device and help you decide which LAS unit fits best!

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