Centre county Pennsylvania, USA | Attached graphic shows FAA's Vertical Protection Level (VPL) for aircraft that are currently using WAAS. Note that WAAS is providing about 20 meters VPL for most of US, To estimate WAAS accuracy degradation in your area find the the VPL from that map for your area, then divide that VPL by 20 meters, if that ratio is one then WAAS service is as good as can be anywhere. Higher ratios are an indication of severity of WAAS degradation for that area. The sharp cutoff in northeast US and eastern Canada are the limit of coverage for AOR-W (PRN 122) in it's new Pacific ocean position. When FAA certifies the new WAAS satellite (PRN 135) for service (sometime this fall), that sharp cutoff will move further east. Not all WAAS enable Ag receivers are programmed to receive PRN 135 so your receiver may need a firmware upgrade before it can take advantage of better eastern coverage that will be provided by PRN 135.
 (WAAS Vertical Protection Level coverage.jpg)
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 WAAS Vertical Protection Level coverage.jpg (57KB - 474 downloads)
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Waas signal in Ontario (Eastern parts)
