What is the impact of platform altitude, can it be limited?
The location calculation assumes that the platform is at a fixed pre-defined altitude. An error on platform altitude translates into an error varying between half and four times this error on longitude. To enhance location accuracy, CLS applies a digital elevation model (DEM) from the USGS to all location calculations for terrestial mobiles and birds. Composed of basic squares of 30 seconds of an arc (900 meters at the equator) for which the altitude is known, the DEM is used to estimate PTT altitude and enhance location accuracy.
