The Federal Aviation Administration (FAA) recently decommissioned two WAAS GPS satellites and activated two replacement satellites. This means the WAAS firmware in certain older and some current model GPS receivers are no longer able to receive WAAS correction signals. There are a number of ways to determine if your GPS receiver is receiving signals from the new satellites. If your GPS unit has a satellite status page, which most do, check to see if it is receiving data from satellite #51 on the east coast and/or satellite #48 on the west coast. If you are not receiving the data, you will need to either upgrade the firmware in your present GPS, change some settings or replace it entirely to obtain the improved accuracy provided by WAAS corrections.