On a Garmin GPS product, is it better to use normal GPS mode or WAAS?

Question

On a Garmin GPS product (i5), is it better to use normal GPS mode or WAAS?

Answer 1

You won't get any benefit from using WAAS mode. You will very likely not be able to get the satellites which are very low on the horizon, which works well for airplanes but not for cars. Furthermore, using WAAS uses more power and drains your batteries faster if you're using battery mode.

Answer 2

Most likely it will not work. In order for a GPS to work out of the car, it must have certain features called pedestrian mode and/or off road mode. Pedestrian mode is a feature that some GPS models have that will enable the GPS user to switch the GPS from their car to foot - walking, hiking, bike riding, or any activity/sport that does not include wheels. Garmin is an activity specific brand GPS. Normally if you want a Garmin to be specific you would have to pay for that particular model. There is no such thing (really) as an all inclusive Garmin. Check to see if the Garmin that you own has pedestrian mode. If not, there is no chance that it will work for bicycle routes. You would probably need something like the Newelectronx Navigator GPS which has pedestrian mode and off road mode. These 2 features are essential for bicycling. If you plan to ride on the street then the Garmin should be perfect, but if you want to bike restricted trails and lanes then get something else more specific for that sport.

Answer 3

Let's step back for a minute and talk about what WAAS is. WAAS provides additional error correction to the information coming from the GPS satellites. It is only available in the USA and areas close to the USA. Basically a ground signal listens to the GPS satellites, figures out if any error correction needs to be applied, and then sends that information back to the satellites for them to distribute back to GPS users on the ground.



WAAS does more to increase the precision of the calculated location vertically than it does horizontally. So in that sense it doesn't do much for cars. It is true that WAAS will typically degrade battery life a little bit. If you are in the USA and your GPS isn't giving you as accurate of a position as you need (and you know it isn't a problem with the map accuracy) then WAAS could help. And if your GPS is always connected to a stable power source (versus batteries) then there is no harm turning it on.



Getting WAAS correction information isn't limited to satellites on the horizon. The correction information is sent up to basically all of the satellites which can then broadcast the correction information. On a 12 channel GPS receiver it isn't uncommon to be receiving WAAS correction information from say 8 satellites.



So in short... if you are running on battery power you should balance the need of slightly greater accuracy with reduced battery life. If you are using a stable power source and are within the WAAS coverage area (most of the USA) there is no harm leaving it on.