Re: Garmin GPSMAP 60CS Accuracy Question

The satellites required for WAAS accuracy augmentation are orbiting in
Geosynchronous orbit over the equator.

They are already low in the sky as far north as Omaha. In Michigan they might
be near impossible for the receiver to see without a good external auto antenna.

If you can find a high point, hill, overlook, building, or other place with a
clear view of the open southern sky, you might be able to get the GPS to see the
WAAS satellite (should be #35 around where you are) and get the 6-7ft accuracy
that is possible.

I normally see 6-7' epe travelling down the interstate (open skies) with my
external roof antenna connected.

Standing near any sort of cover or disruption that goes higher than 25 degrees
above the level southern horizion will probably block out your view of the WAAS
satellite.

http://www.garmin.com/aboutGPS/waas.html

Read the section "Who benefits from WAAS"
There follows your "frozen lake" scenario.

http://www.treasurewise.com/catalog/gps/p3020.htm

I have seen EPE as low as 9ft without WAAS but that was during the Iraq wars
when the USAF was updating the satellites own position data a lot more
thoroughly than they normally do.