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Old August 7th 14, 09:15 PM posted to rec.aviation.soaring
jfitch
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Posts: 1,134
Default Another mid-air (UK)

On Thursday, August 7, 2014 8:49:07 AM UTC-7, Stats Watcher wrote:
At 15:04 07 August 2014, jfitch wrote:



Isn't the Flarm GPS WAAS corrected? The WAAS standard of


performance is

1.6M nominal horizontal (95%). When the NDGPS system is


functional (and GPS

engines take advantage of it) this will be reduced to 15 cm.






Not in Europe as WAAS is US only. A search of the Powerflarm

website returned 0 (zero) occurrences of the term 'WAAS'. So it

seems unlikley.... Same result for NDGPS, so that seems unlikely

too.. If someone finds something different I will obviously be wrong

but until that point it's still +-16m (ie a whole wingspan) at 99%

confidence


From the Flarm.com product page:

"FLARM incorporates a high-precision WAAS 16-channel GPS receiver and an integrated low-power radio transceiver. Static obstacles are included in FLARM's database."

Nevertheless, WAAS is intended to correct for atmospheric and geometric anomalies, to improve absolute position accuracy. For gliders in close proximity, these errors are tracking. The fact is, the Flarm GPS has several times the accuracy required to perform the expected function.