|
The Pseudorange (from pseudo and range, nothing to do with the fruit!) is a first-approximation measurement for the distance between a satellite and a navigation satellite receiver - for instance Global Positioning System (GPS) receivers.
To determine its position, a satellite navigation receiver will determine the ranges to (at least) three satellites as well as their positions at time of transmitting. Knowing the satellites' orbital parameters, these positions can be calculated for any point in time. The pseudoranges are then the time the signal has taken from there to the receiver, multiplied by the speed of light.
To measure this time, the relationship between the local time (derived from a cheap quartz oscillator) and GPS time must be known. This is done by introducing t into the positional computation, requiring one extra satellite signal. With four signals, solutions for the receiver's position along the x-, y-, z- and t- axis can be computed.
Following the laws of error propagation, the ranges are not computed exactly, making it sensible to speak about pseudoranges, rather than ranges.
| This article belongs in one or more categories. Please categorize this article so that others may find this article from other articles in the same categories. Once this article has been properly categorized, please remove this notice.
|
|
