Deciding which unit is best is a subjective choice. In general, users asking this question are usually trying to avoid GPS units with unacceptable performance rather than trying to buy the absolute best GPS unit. Nearly all of the GPS receivers work reasonably well. The main differences between GPS units are associated with the amount of time it takes to determine a fix from available satellites, the accuracy of the position fix, and the sensitivity of the GPS receiver
. Other factors to consider are the ability to log where you've been, the ability to download route data from the receiver (generally a feature of all-in-one handheld units), and form factor. Many users have reported great success with the Rikaline and BU-303 models.
There are some features which can affect accuracy or might be desirable. WAAS stands for "Wide Area Augmentation System" and will provide a more accurate fix than one without this feature. Some devices are receivers only without displays
so will require a connection with your computer, however they typically can be mounted outside so have a better view of the GPS satellites. If you want to "take it with you" you will need one with a display. Some include maps onboard
, some require them be downloaded from a PC. If you have a map-capable GPS and plan on traveling outside the USA (even Canada or Mexico), you might want to check if such maps are available. Some units have no external interface, but if you just want a stand-alone navigation
unit they might be better than one that can talk to your PC. Most GPS units update once per second. Garmin and others make 5Hz (updates 5 times per second) GPS modules which increase precision and update speed of tracking.
A thread that compares receivers side by side