You might want to consider the implications of WAAS. I have no direct
experience, but the principle is that you take an external signal and use it
to 'correct' the GPS location to another place - hopefully more accurate.
But what is to stop you sending bogus 'corrections' and making the GPS think
its somewhere else entirely ? The WAAS signals are much easier to generate
than the original GPS satellite signals. Sounds an easy way to cheat to me.

--
Regards,

Adrian Jansen
J & K MicroSystems
Microcomputer solutions for industrial control
"Ivan Kahn" wrote in message
news:hFPwb.225716$mZ5.1710772@attbi_s54...
"Tim Newport-Peace" ] wrote in message
...
X-no-archive: yes
In article _1vwb.96689$Dw6.473262@attbi_s02, Ivan Kahn
writes
I was wondering if any of the manufacturers are considering submitting
for
IGC approval a GPS WAAS system that does not incorporate a barograph?
Seems
to me that such system is far more accurate then those that incorporate
a
barograph, and should also never need calibration.

Ivan


Most unlikely as it the Technical Specification requires a barometric
record.

While I have no intention of entering into a long discussion on why
barometric traces are required, the comparison between barometric and
GPS altitude is a useful check and in the event of GPS signal being lost
temporarily, the barometric trace will prove flight continuity.

GPS altitude cannot be used for checking for Airspace Infringements and
this would invalidate it's use in many competitions.

Tim Newport-Peace

"Indecision is the Key to Flexibility."

I agree, why traces are needed is really the point. But I believe a GPS
with
WAAS is far more accurate than a barograph and should also be more cost
effective. But unless someone seeks approval then I would not expect any
specification to change. I was just wondering if there is any movement in
this area.

Ivan