About GPS Satellite Quality and Status

When there is obstruction between the GPS antenna and the GPS satellites, signals cannot be received. Since at least three signals must be simultaneously received to establish your position, Navigation cannot establish your position by GPS in the following locations.

When an obstruction (a load or the like) exists on or in the vicinity of the GPS antenna, it may not be possible to receive signals from the satellites.

• Since the GPS satellites orbit the earth, the reception of signals at a given position varies with time. Note also that signals from satellites close to the horizon are susceptible to the effects of obstructions.

• GPS satellites are managed by the US Department of Defense and their accuracy is sometimes reduced deliberately.