TomTom 1650 GPS fix

it's not a program, it is the projected positions of the gps satellites for the next few days. supposed to help the pnd locate satellites faster.

blake7mstr is 100% correct. It is a DAILY free update service, the same as Map Share is. There is no need to update your unit daily. Just do so before you intend to use it.

I ignore the update and only include it if there is some other update. The time it takes to get a fix is negligible between the update or not.

Since it is a DAILY free update service, the same as Map Share is, there is always some other update to download with it.

Even though my GO930 and VIA 1535TM are pretty quick getting a fix without the update, I've noticed a slight improvement when I get a new GPS fix.

I dragged a tomtom 1 out of the cupboard and tried it, after 3 years in the cupboard there was still life in the battery, but it took 90seconds to find a satelite
gps fix applied, 5 seconds
the further out of dae the version, must be worse effect.
since the rotational errors would be tiny at first

There is very, very little air at the altitudes of the satellite orbits, but there is still a little, and drag of this air on the satellites can cause their locations to change with time. (There are other factors that also have an effect, but my understanding is that air drag is the largest factor.)
The GPS Fix information updates the probable locations of the satellites, making it possible to obtain your location more rapidly than would be the case without an approximate starting point for the satellite locations.

- Tom -

GPS satellites are in what is termed a LEO or low earth orbit which essentially means they will not be found in the same place in the sky every time. The big communications satellites used for voice and video transmissions are in a geostationary location which means their distance from the earth makes them appear to be always at the same relative location in respect to the horizon. Three or four Geosynchronous satellites can pretty much cover the entire earth (except near the poles) while it takes several satellites operating in low earth orbit to accomplish the same. The "fix" your GPS receives does, as you state, download a table which tells the GPS how many and at what position the 3 or more satellites it sees will be in and which satellites will be coming into "view" from your area and which ones will be leaving view.

Geosynchronous orbits are usually over the equator and at an altitude of 22,600 miles (36,370 km). These orbital "slots" are controlled by international treaty.