Does The GPS system has an accuracy drift no matter the corrections applied to it?
anuraganimax asked:
I heard from somewhere that due to unknown reasons the GPS system suffers an accuracy drift of 1 ns/day and sometimes randomly. If this is the case will the GPS system stop working someday??
I heard from somewhere that due to unknown reasons the GPS system suffers an accuracy drift of 1 ns/day and sometimes randomly. If this is the case will the GPS system stop working someday??
The orbit of GPS satellites will eventually all decay without more boost to keep them in orbit due to the VERY thin distribution of particles still about, even in space, which slows down the satellites.
However modern GPS equipment takes this and the relativistic affects of the signal travel into account so a simple Lorentz transformation plus a small correction factor (long term) would fix any signal read error. (Plus Satellites periodically do a relativistic time-resynchronization with their ground communication systems)
Plus, 1E-9 seconds a day won’t exactly make your Garmin give you bad directions….and I’d also think that poor atmospheric conditions can easily cause a signal to be 1E-9 seconds slower to reach the ground, accounting for that “randomness” factor. (Think of the Refractive index with snell’s law… the speed of the wave changes in each new medium) GregTheGymnast
The GPS signal can be “differential corrected” which puts it dead-on within the limits of the accuracy of the equipment. A known receiver (It knows where it is in 3 dimensions) gets where the GPS system thinks it is. The receiver then corrects the position. This information can then be broadcast to correct other receivers OldPilot
Short answer: No.
The GPS system has all sorts of an accuracy errors, how many of these can be corrected depends on how much time and money you are willing to spend on the problem. These errors change depending on all sorts of things like time of day and recent sunspot activity but there is no consistent drift if you average over a long enough time. GPS accuracy is going to get worse over the next few years due to where we are in the ~11 year solar cycle but then it will start to get better again.
Individual GPS satellites do have clock drifts and orbital drifts. The GPS ground control stations monitor these, calculate the corrections that need to be applied due to these drifts and upload that data to the satellite which then includes it as part of it’s transmission.
Assuming the system is running as intended any drift over time is canceled out in this way.
If some some reason all of the the ground control stations stopped working then the correction information would become out of date and GPS accuracy would start to decrease over time.
However if something had happened that simultaneously knocked out 4 different US military bases scattered all over the globe then your GPS being a few meters less accurate than it used to be is probably not going to be your biggest concern. Andrew A