Utter bollocks
This is an excellent example of garbage marketing.
Yes, *in theory* use of the different band allows greater precision. But so does sampling more than 3 satellites. Given the GLONASS, Compass, Beidou, and other satellite positioning systems available, the feasibility of using many satellites vs. just 3 GPS ones is actually more feasible/easier.
More importantly, however, the problem in "concrete canyons" isn't the precision of the distance calculation and/or clock data. The problem is multi-path interference.
Since the GPS signals are radio, reflections of same signal off the ground, buildings, etc arrive at different times than the straight path signal. If the straight path signal is present, you can calculate the distance to the satellite and discard the longer paths (reflections). However, if the straight line path is not present - i.e. blocked by a tall building or whatnot, you *cannot* distinguish a multipath reflection from the straight line unless you have also know the position of the satellite vs observer plus an accurate 3D map of the buildings.
I can pretty much guarantee the chip doesn't do that.
Biting the hand that feeds IT
