GPS is everywhere! You have probably used and benefitted from GPS. They are found in most of the smartphones, many new automobiles and now even in smart watches. It helps you to get where you want to go. These tiny devices can give your position and time simultaneously almost anywhere on the planet.

But what is GPS? In this guide we will give an insight of what is GPS, how it works and what are the applications of a GPS module. 

What is GPS  

GPS (Global Positioning System) is a satellite-based navigation system. It provides time and location-based information to a GPS receiver, located anywhere on or near the earth surface. GPS works in all weather conditions. 

The satellite system consists of a constellation of 24 satellites in six Earth-centered orbital planes, each with four satellites, orbiting at 13,000 miles (20,000 km) above Earth and traveling at a speed of 8,700 mph (14,000 km/h).

While we only need three satellites to produce a location on earth’s surface, a fourth satellite is often used to validate the information from the other three.

The GPS modules have become small over the years. These modules have tiny processors and antenna that receive data sent by the satellites and compute your position and time.

Working of GPS

GPS works through a technique called trilateration. Trilateration is the process of determining your position based on the intersection of spheres. When a receiver receives a signal from one of the satellite, it calculates its distance from the satellite considering a 3-D sphere with the satellite located at the center of the sphere. Once the receiver does the same with 3 other GPS satellites, the receiver then proceeds to find the intersection point of the 3 spheres to calculate it’s location. Used to calculate location, velocity and elevation, trilateration collects signals from satellites to output location information.

 The GPS module receives a timestamp from each of the visible satellites, along with data on where in the sky each one is located (among other pieces of data). From this information, the GPS receiver now knows the distance to each satellite in view. If the GPS receiver’s antenna can see at least 4 satellites, it can accurately calculate its position and time. 

A single satellite broadcasts a microwave signal which is picked up by a GPS device and used to calculate the distance from the GPS device to the satellite. Since a GPS device only gives information about the distance from a satellite, a single satellite cannot provide much location information. Satellites do not give off information about angles, so the location of a GPS device could be anywhere on a sphere’s surface area.

When a satellite sends a signal, it creates a circle with a radius measured from the GPS device to the satellite.

When we add a second satellite, it creates a second circle, and the location is narrowed down to one of two points where the circles intersect.

With a third satellite, the device’s location can finally be determined, as the device is at the intersection of all three circles.

Applications of GPS

GPS is a powerful and dependable tool for businesses and organizations in many different industries. Surveyors, scientists, pilots, boat captains, first responders, and workers in mining and agriculture, are just some of the people who use GPS on a daily basis for work. They use GPS information for preparing accurate surveys and maps, taking precise time measurements, tracking position or location, and for navigation. GPS works at all times and in almost all weather conditions. There are main uses of GPS:

• Location - Determining a position.
• Navigation - Getting from one location to another.
• Tracking - Monitoring object or personal movement.
• Mapping - Creating maps of the world.

Parameters for Selecting the Right GPS Module

1. GPS Pulse Accuracy

This is the accuracy of 1Hz pulse received from GPS module or chipset.

2.      GPS Sensitivity

Minimum level of signal that allows GPS receiver to acquire or track the GPS signal.

3. Acquisition sensitivity

 Minimum level to successfully get GPS signal information while system powers up first time. 

4. Tracking sensitivity

 Minimum level to maintain location fix once it has been attained

5.      Interface Type

When we use any GPS chipset or GPS module, then over some interface, we need to get the GPS packet information. That interface could be UART, I2C, SPI etc.

6.      Operating Supply Voltage

This is the voltage over which GPS module or chipset works.

7.      Operating Temperature Range

If using GPS module for outdoor applications, then minimum and maximum operating temperature range shall be checked.

Given Below is a list of some of the best GPS modules that can be used for various applications and projects.

1.      SIM808 GSM/GPRS/GPS Bluetooth Compatible Development Board With GPS Antenna

2.      Ublox NEO-M8N GPS with Compass for Pixhawk with extra connector for APM

3.      SIM7600EI 4G LTE High-Speed Modem GPS/GNSS IoT board

To explore more such GPS modules Click Here.