From GPS to GNSS
In 1978, the first American satellite was launched into an earth orbit. Since then, determining one’s own position has been possible with this global satellite system. The term GPS (Global Positioning System) has since become the standard synonym for all satellite-based navigation systems. But the reason why it is incredibly important to talk about GNSS (Global Navigation Satellite System) nowadays and why GNSS enables a major increase in the performance of inertial navigation systems is explained in this whitepaper.
The Challenge
GNSS stands for Global Navigation Satellite System and includes the satellite systems GPS, GLONASS, GALILEO and BEIDOU. For a valid and very precise position solution, the GNSS receiver requires at least 6 different satellite signals. Modern GNSS receivers are capable of using all satellite systems simultaneously and intersecting the best satellite signals in each position. This enables navigation in situations where one satellite system alone would not be adequate, such as in urban canyons or tree-lined avenues. The situation becomes particularly critical when the GNSS receiver receives reflected satellite signals: the so-called multipath effect. In such cases, the receiver may include incorrect information when calculating the position solution, resulting in decreased accuracy. The more satellites the GNSS receiver can use for solution determination, the greater the likelihood of compensating for or eliminating these multipath effects.
