GPS problems are not that common anymore as GPS units have significantly improved in both terms of reliability and software. The electronics has improved as have most things and the system is no longer subject to deliberate degradation. The modern boat GPS is generally very reliable if properly installed and setup in accordance with manufacturers instructions. But there are factors that are beyond the average boaters control. But if your navigation depends on accurate GPS information you do need to understand the larger factors.
Errors can be as great as 20-30 meters during the day and 5 meters at night. There is the Multipath Effect which occurs when signals from a satellite travelling to a receiver arrive at slightly different times due to reflection or alteration. The effect is that positions may be derived off the “bad” signal, resulting in an inaccuracy. Finally there is satellite integrity where the signal being transmitted from a satellite is corrupt due to a malfunction, and not very common.
The GPS has inherent errors that decrease accuracy. There are GPS Clock Errors. Each GPS satellite has two atomic clocks and these are monitored against terrestrial atomic clocks. Based on this information, the entire GPS system is continually calibrated against UTC. There are ionosphere or space weather effects. Like radio signals, both ionosphere and troposphere conditions can affect GPS accuracy. That is where space weather impacts come in.
Space weather is real and can cause problems with GPS. Errors occur in signal transmission times that can impose signal propagation delays. This signal refraction introduces timing errors that cause positional inaccuracies. Like radio propagation it alters given changes in atmospheric conditions, solar activity, etc. This can include ionospheric scintillation. The space weather can be from geomagnetic storms on the sun, increased sunspot activity, Coronial mass ejections (CME’s), solar flares and so on.
The sun earth environment has a role to play in many issues. This is the region extending from the sun’s surface to the earths ionosphere and magnetic field. It is dominated by electromagnetic radiation and electrically charged particles emanating from the sun. The sun is by its’ violent nature prone to dramatic and violent changes, with events such as solar flares, and the resultant blast streams of radiation and energized particles that stream towards earth. The effects of space weather are dramatic on our communications systems and GPS marine navigation systems and all are affected by space weather. Understand the affects and how to deal with it. More great boat GPS information from fishing and boats.