We're going to look at two bands, the L1 and L5, since these were the two mentioned by Apple in the iPhone 14 Pro and Apple Watch Ultra event. L1 is the oldest of the GPS signals, and is actually made up of two different signals:Precision Code (P-code): This is reserved for military useCoarse/Acquisition Code (C/A): The signal that's open for civilian useNow, L1 is reliable and highly accurate. It's fitted to countless devices, and we've been using it for years. But it has a limitation.The signal doesn't pass through obstacles all that well. Buildings, big trees, and even dense foliage can weaken or block the signal. GPS signals can also be reflected off buildings or walls, resulting in what's known as multipath error.This is where L5 comes in. This is a newer signal designed to eliminate many of the weaknesses associated with the L1 signal and adding the ability for greater signal processing to remove erroneous data.