GPS is a satellite-based navigation system using 29 satellites (minimum of 24 active satellites). The full name of the system is “Navigational Satellite Timing and Ranging – Global Positioning System – NAVSTAR-GPS." Originally, this system was developed by the US Department of Defense. The system officially launched in 1995. All satellites move about in an exact orbit to receive signals from 6-10 satellites from every position in the world, and a minimum of 4 at the same time. Every GPS satellite sends C/A coded data with 1575.42 MHz in the civil L1 frequency band. Besides position and time, a special satellite code is also sent to clearly differentiate from other satellites. The GPS receiver decodes these signals (CDMA). The highly precise military P/Y code is not public
If the GPS sensor receives signals from a minimum of 3 satellites, the position can be precisely analyzed by the sensor: latitude and longitude. Signals from 4 satellites allow calculation of altitude as well (= height above sea level). In aviation, “height” is generally used to measure the distance between the sensor and the ground. The more satellites, the higher the accuracy.
When powering up the QuantumX system and the GPS sensor for the first time, it will begin searching for satellites. This process can last up to 5 minutes. After the GPS has been initialized it usually takes less than a minute to get all the signals. This is checked by software.