Understanding the Functionality of Satellite Navigation Systems

Understanding How Satellite Navigation Systems Operate

To grasp how satellite navigation systems serve various purposes, it's essential to understand their basic working principles. This overview simplifies the complex technology behind these systems, focusing on the US GPS network, which is among the most reliable globally.

The GPS constellation includes 24 satellites orbiting Earth continuously, completing two orbits daily at an altitude of approximately 20,000 km and inclined at 55 degrees. This configuration guarantees that at least six satellites are visible from any location, with only three needed to pinpoint a user's position. This is part of the three main components: space segment, ground control segment, and user equipment.

Satellite navigation relies on triangulation, a technique dating back to traditional navigation methods involving landmarks, maps, and compasses.

In simple terms, if someone is lost in a wilderness, they can determine their location by identifying three landmarks, where their position lies at the intersection point of the circles centered on each landmark with radii equal to the distance from the person to each landmark.

Applying this principle to satellites, the receiver interacts with three orbiting satellites placed 20,000 km away. The receiver’s position is found at the intersection of three spheres, each with a radius corresponding to the satellite's distance. Determining the precise distance involves measuring the time taken for signals traveling at light speed (300,000 km/s) to reach the receiver. Corrections for atmospheric interference are also incorporated to enhance accuracy. The remaining calculations are handled within the receiver based on specific application needs.