How GPS Tracking Software Works

GPS Overview

The Global Positioning System (GPS) is a feat of modern-day technology that accurately provides the position of a tracked item regardless of the weather, at any time of day or night. Run and owned by the US Government, GPS is a satellite-based radio-navigation system comprising a total of 24 connected satellites that act as electronic waypoints to track items and people.

GPS System Applications

Common applications for the GPS system include:

• Navigation and map following for land-based vehicles.
• Package delivery tracking and time estimation.
• Inventory logistics and stock control.
• Military applications.
• Aviation and shipping identification and tracking.
• Geofencing and the identification of virtual barriers.
• Wayfinding in recreational activities such as mountain biking.
• The tracking of endangered species such as whales and rare birds.

Because the GPS system is always available, it is the perfect tool for tracking difficult subjects such as ocean-borne mammals and birds. In addition, GPS provides much-needed information for the delivery of military ordinance, making military operations much safer for civilians. On a more day-to-day level, most large industrial and commercial companies use GPS to control their stock. For example, Amazon uses these systems to not only move stock around their warehouses but also to follow deliveries to customers.

GPS Tracking Software

The network uses a CDMA spread-spectrum method where the low-bitrate message data is mixed with the high-rate pseudorandom code - a string of numbers known only to the satellite software - that is different for each satellite. The person on Earth needs to find the PRN codes for each satellite to create the right message data. The gadget can find its place accurately when it receives signals from at least three different satellites. This location changes as new satellites become visible and replace those that go out of sight. Figure 1, below, shows the basic operation of the GPS system.

Figure 1: Basics of GPS.

The GPS tracking satellites use a special software called the "Navigation Message Generator." This software has complicated formulas that work together to calculate and send accurate time and position information. GPS systems on Earth can determine their location by receiving messages from several satellites. This software is installed in the satellite's computer and can't be viewed by anyone who is not allowed to use it.

GPS System Functions

The GPS system has two main functions:

• It generates navigation signals containing specific information. This includes satellite clock time, orbital data, and system health, and transmits them between other satellites and Earth.
• It has a control system that is monitored by a network of ground-based stations. These stations can send updates to the satellites to maintain accuracy and adjust their positions if needed.

The system allows for precise control and reliable real-time position tracking. Each unit's signals are regularly checked and compared to expected data from ground control stations on Earth. Any differences between the two are automatically adjusted.

With the inter-satellite communications set, the main issue becomes the software link that is used to pair the GPS satellites to the Earth-based systems and thereby determine their position.

GPS Device Software

The base program that is responsible for the main functions of a GPS system is usually referred to as "GPS daemon" (GPSd). This program gathers data from a GPS receiver and then shares it with other applications over an IP network. This allows multiple programs to access location information at the same time. It is often used on operating systems that are similar to Unix software.

Modern GPS software is fairly simple in its structure and can be obtained from either paid-for or open-source code. The positional accuracy of either package is very much the same, but paid-for systems may have additional features such as travel history and saved locations.

All device-based GPS software packages have a number of features that are essential to the operation of the system. These are:

• Positioning capability: The onboard software identifies the location of the device being tracked using signals from multiple and linked satellites.
• Route planning features: The software must be able to calculate the best route based on the user's needs. This will include a starting point, a final destination, and the best route to get between the two. The software must also be able to replan the route if the user chooses to go another way.
• Location history: The software must have a tracking system to show where the unit has been.

This last feature requires that the software retain offline maps and route information and include bookmarking so that locations can be saved for future use. This feature allows users to store favourite locations - such as home or work - into their GPS tracking device and be given a route at the touch of a button.

GPS is a low-cost solution to the accurate tracking of vehicles and packages that relies on specialist software to operate the satellite system. The software also allows the satellites to communicate with the tracked items on Earth. Without any one of the essential components - satellites, inter-satellite software, communications software, and receiver/interpreter - the whole system would be ineffective.