>What does a six-channel GPS receiver even mean? Is more channels more better?The operating principle of GPS is more complex than I can usefully summarise in a comment, but essentially the satellites are continuously broadcasting an extremely accurate time signal that the receiver uses to calculate the time-of-flight to each satellite. GPS receivers need signals from a minimum of four satellites to provide a location fix.
There are usually more than four satellites visible, so additional channels allow for more than the minimum number of signals to be received. this can provide improved accuracy, faster time-to-first-fix and better resilience to interference. If you're receiving five or six signals, you don't lose your positioning fix when one of the satellites moves below the horizon or is obstructed by terrain. Reflected signals can cause error, because the time-of-flight of the signal will be greater than the actual distance to the satellite; extra channels allow these errors to be compensated for.
For a long time, GPS receivers typically had no more than 12 channels, which was the maximum number that would actually be useful given the limited number of satellites in the original GPS constellation. Since then, many other navigation satellite constellations have launched, so between 40 and 60 navigation satellites are typically visible at any moment. Receivers have commensurately improved, with even basic receivers often having upwards of 48 channels.