Implausible Time Records

On Tuesday, May 7, 2019 at 4:30:05 AM UTC-4, Tim Newport-Peace wrote:
... I have seen similar time sequence errors in other recorders over the years...

IIRC I've seen this from a number of GPS engines;
certainly I've got some Garmin engine logs like this.
The problem is naive software that doesn't filter
'obviously' wrong stuff from the GPS engine, including
time going backwards and stupendous position jumps.
Some nice example traces here momentarily detour
from Montana into the North Atlantic for example...

None of my collected examples were (to my best
understanding) related to jamming.

Its important not to trust too much the inputs ;-)

See ya, Dave

On 5/7/19 10:10 AM, Dave Nadler wrote:
On Tuesday, May 7, 2019 at 4:30:05 AM UTC-4, Tim Newport-Peace wrote:
... I have seen similar time sequence errors in other recorders over the years...

IIRC I've seen this from a number of GPS engines;
certainly I've got some Garmin engine logs like this.
The problem is naive software that doesn't filter
'obviously' wrong stuff from the GPS engine, including
time going backwards and stupendous position jumps.
Some nice example traces here momentarily detour
from Montana into the North Atlantic for example...

None of my collected examples were (to my best
understanding) related to jamming.

Its important not to trust too much the inputs ;-)

See ya, Dave


I can't fault software for failing to filter out bad data. Having
submitted a number of logs to OLC from a cell phone, I don't see the
type of errors described here. Maybe better gps engines are in order?
Seems like producing good data is better than filtering out bad data.

I can't fault software for failing to filter out bad data.Â* Having
submitted a number of logs to OLC from a cell phone, I don't see the
type of errors described here.Â* Maybe better gps engines are in order?
Seems like producing good data is better than filtering out bad data.

What you say has merit, but I can't see opening up my ClearNav computer
and vario and attempting to replace the GPS engines.

Since both and my PowerFlarm portable experience the drop outs, I've got
three new antennae on order.Â* We'll see how that works.

Funny how this just started happening in the end of April...
--
Dan, 5J

On Wed, 08 May 2019 08:58:39 -0600, Dan Marotta wrote:

Funny how this just started happening in the end of April...

I thought: have you got another logger you could leave running on the
field away from the runway but where it gets a decent signal?

If that also gets the time hiccup, then you'll know the problem is
outside the Stemme.


--
Martin | martin at
Gregorie | gregorie dot org

I have a Dell Streak in the cockpit (right side) for my wife's use. It
also records an igc file which I can post on skylines.org.Â* It is not
acceptable to OLC due to no ENL recorder.Â* Maybe the XCSoar troops would
write a module to access the Streak's microphone and record engine
noise...Â* Or maybe one of the XCSoar clones already does that?

On 5/8/2019 12:16 PM, Martin Gregorie wrote:
On Wed, 08 May 2019 08:58:39 -0600, Dan Marotta wrote:

Funny how this just started happening in the end of April...

I thought: have you got another logger you could leave running on the
field away from the runway but where it gets a decent signal?

If that also gets the time hiccup, then you'll know the problem is
outside the Stemme.



--
Dan, 5J

I see a flight on Jan 27 this year that had the same highly compressed
altitude graph, so something wasn't right well before end of April.

Sounds like you've got problems due to jamming, in addition to at least
one other issue.

Should be plenty of other gliders flying out of Moriarty to compare logs
with. Suppose you could submit one from the Dell Streak and lie about
the glider type, then delete it after seeing how OLC likes it.

-Dave



On 5/8/19 4:28 PM, Dan Marotta wrote:
I have a Dell Streak in the cockpit (right side) for my wife's use. It
also records an igc file which I can post on skylines.org.Â* It is not
acceptable to OLC due to no ENL recorder.Â* Maybe the XCSoar troops would
write a module to access the Streak's microphone and record engine
noise...Â* Or maybe one of the XCSoar clones already does that?

On 5/8/2019 12:16 PM, Martin Gregorie wrote:
On Wed, 08 May 2019 08:58:39 -0600, Dan Marotta wrote:

Funny how this just started happening in the end of April...

I thought: have you got another logger you could leave running on the
field away from the runway but where it gets a decent signal?

If that also gets the time hiccup, then you'll know the problem is
outside the Stemme.

Good idea.Â* I noticed the time compression some time ago but chalked it
to OLC doing something new.Â* It's cloudy and rainy today but I need to
go to the airport anyway.Â* I'll get the Streak.

On 5/8/2019 7:58 PM, kinsell wrote:
I see a flight on Jan 27 this year that had the same highly compressed
altitude graph, so something wasn't right well before end of April.

Sounds like you've got problems due to jamming, in addition to at
least one other issue.

Should be plenty of other gliders flying out of Moriarty to compare
logs with.Â* Suppose you could submit one from the Dell Streak and lie
about the glider type, then delete it after seeing how OLC likes it.

-Dave



On 5/8/19 4:28 PM, Dan Marotta wrote:
I have a Dell Streak in the cockpit (right side) for my wife's use.
It also records an igc file which I can post on skylines.org.Â* It is
not acceptable to OLC due to no ENL recorder.Â* Maybe the XCSoar
troops would write a module to access the Streak's microphone and
record engine noise...Â* Or maybe one of the XCSoar clones already
does that?

On 5/8/2019 12:16 PM, Martin Gregorie wrote:
On Wed, 08 May 2019 08:58:39 -0600, Dan Marotta wrote:

Funny how this just started happening in the end of April...

I thought: have you got another logger you could leave running on the
field away from the runway but where it gets a decent signal?

If that also gets the time hiccup, then you'll know the problem is
outside the Stemme.





--
Dan, 5J