Thread: "Flarm, no GPS"
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Old July 6th 15, 06:54 AM posted to rec.aviation.soaring
jfitch
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Default "Flarm, no GPS"

On Sunday, July 5, 2015 at 10:00:07 AM UTC-7, Tim Newport-Peace wrote:
At 00:31 05 July 2015, jfitch wrote:
On Thursday, July 2, 2015 at 10:12:49 PM UTC-7, jfitch wrote:
I am getting this bitching Betty alarm every so often. It may do it for

a=
minute or so, then goes away, then comes again.=20
=20
Looking at the Flarm IGC file, there are comment lines that look like

thi=
s:
=20
LFLA213757GPS 7 45=20
=20
Which I believe represents GPS status (7 satellites?)
=20
Then I get some that look like this:
=20
LFLA213857GPS 0 0
=20
No satellites? The B field time stamps show a lat and long 4 seconds

befo=
re and 4 seconds after. In the flight today I got 14 of these and about
tha=
t many warnings (I didn't count the warnings).=20
=20
This didn't happen last year, started coincident with the 6.0.2

firmware
=
"upgrade".=20
=20
Can anyone shed any light on this? Can't find any spec from Flarm that

de=
scribes it.

I have now written an XL parser for the Flarm IGC file, which counts the
in=
stances of dropped fixes. I found no dropped fixes at all from flights in
2=
013. I found dropped fixes in one flight in 2014, 56 dropped on one
particu=
lar flight, none in any others. I have now 3 flights in 2015 with the new
f=
irmware. 1st flight shows 19 dropped fixes, 2nd flight 373 dropped fixes,
3=
rd flight 882 (and all fairly short flights too). Not an encouraging
trend.=
=20

The reason I am now aware of it, is that the new Flarm firmware announces
b=
ad fixes with the Lxxxxxx GPS 0 0 comment line, and the Air Vario
announces=
it to me with a voice warning. Didn't do that before.

Not beyond the bounds of possibility that reporting No GPS in the L-record
is a new feature Introduced with Version 6?


As I said, this was introduced in V6. The same information was available in the B record in prior versions, but you had to dig for it a bit more. Of course the Vario is not looking at the IGC file, only the serial stream, which I do not have the equipment to directly capture, so I do not know what changes where made to it, and what changes to the interpretation.