GPS approaches with VNAV vertical guidance

"Barry" wrote in message ...
The plate shows a catagory of "GLS PA DA", which I decode as "GPS
Landing System, Precision Approach, Decision Altitude" (with minimums
shown as NA). Is that the same as the LPV you're talking about?

GLS does stand for "GPS Landing System," and would provide capability
equivalent to CAT I ILS (200 ft decision height/altitude). WAAS was
originally supposed to provide this, but due to integrity issues is only good
down to 250 ft, which is the limit for LPV approaches. Current plans for WAAS
upgrades include better coverage and redundancy, but not GLS. There are
tentative plans to modernize GPS and add a new civil frequency; if this is
done, then WAAS might provide GLS at some time after 2013.

Just a nitpick:

GLS actually stands for "GNSS Landing System." The intention is have
the term encompass any satellite navigation system, of which "GPS"
(the U.S. based system) is (currently the only certified operational)
one.

It can eventually apply to the European, Japanese, Indian, etc.,
systems if/when those systems support it.