Implausible Time Records

At 15:56 26 May 2019, Dan Marotta wrote:

As to the published interference testing times, I didn't check, but the
only dropouts I had were up around Las Vegas (the northeast part of the
flight).Â* Once moving south again, I did not see them again. As stated
before, I lost GPS on everything in the cockpit - all of my stuff and my
copilot's iPad, as well.Â* I'd bet on jamming.Â* I'll try to do better on

what and when next time.

Interestingly, in your flight 2019-05-04-CNI-V8Q-01, not only were there
lots of loss of 3D logging (dropouts), but around 22:23:09 (UTC) the GPS
altitude rose to an amazing 163,215 feet (Eat you heart out Perlan).

Sure would be nice if the gps engines could filter out the worst of
this. 16K to 0 or 160K in a second seems rather umm implausible.

If it is jamming, as it sounds like, expect it to get nothing but worse.


On 5/26/19 9:56 AM, Dan Marotta wrote:
I tried to change either the logging interval or just the interval that
is downloaded after the flight but it was not intuitive after the
flight.Â* I guess a little ground study is in order.

As to the published interference testing times, I didn't check, but the
only dropouts I had were up around Las Vegas (the northeast part of the
flight).Â* Once moving south again, I did not see them again. As stated
before, I lost GPS on everything in the cockpit - all of my stuff and my
copilot's iPad, as well.Â* I'd bet on jamming.Â* I'll try to do better on
what and when next time.

On 5/26/2019 4:04 AM, Tim Newport-Peace wrote:
At 02:38 26 May 2019, kinsell wrote:
On 5/25/19 6:58 PM, Dan Marotta wrote:
I turned on my CN2 and CNvXC 20 minutes before engine start today. Then
it was another 15 minutes to warm up the engine before take off.ÂÂ* Even
though I had several GPS drop outs during the flight, it scored
perfectly.ÂÂ* BTW, all other devices in the cockpit, including my
buddy's
iPad also lost GPS for those times.ÂÂ* Looks like the work around is to
let the GPSs get time synchronized before take off.

Basically, the Time in the IGC file originates in the GPS Engine. At
power-up it comes from the RTC, but once 'Satellite Time' has been
received
and the correct number of Leap Seconds applied, the source switches to
that.

The difference can be in the order of 2 seconds, and this causes the
out-of-sequence times that OLC seems objects to.

There are two workarounds and you can use either or both.

1. Set the logging interval to 4 seconds or more, which will conceal the
2-second jump.

2. As you said, Switch on well in advance. 15 minutes is about right
IMHO.
10 minutes is the time it takes to be assured that the time is
correct, and
5 more to be sure that the FR has not back-logged the jump.

Adding anecdotal evidence to the startup idea... I had my first-ever "implausible time record" failure on my ClearNav two weeks ago. It was an unusual flight, as I realized after takeoff that I didn't have the right databases loaded (turnpoints and airspace) since I was flying "off the map" from our typical task area (it was a really good day). About 45 minutes into the flight I went to load the full US Airspace file, and the ClearNav locked up. I power cycled it and it cleared everything, but a few minutes after the approximate point of the power cycle I got the implausible time record. I did get another one later in the flight as well, but all flights before and since have been fine.

P3

How to change the igc flight log time interval on CN2:
https://youtu.be/AkJwwCbGMZQ

CN2 stores logs internally at 1 second. You can d/l to USB at 1, 2, 4 or 10 second intervals.

Please pay close attention to the voice over. There is one especially non-obvious press of the down arrow key.

We think that d/l at 4 second interval solves (really: masks) the discontinuity that occurs when the UTC - GPS time offset update is received from the GPS system.

best regards,
Evan Ludeman for CNi

Thanks, Evan.

I figured it out at home using the CN2 simulator.

On 5/28/2019 9:48 AM, Tango Eight wrote:
How to change the igc flight log time interval on CN2:
https://youtu.be/AkJwwCbGMZQ

CN2 stores logs internally at 1 second. You can d/l to USB at 1, 2, 4 or 10 second intervals.

Please pay close attention to the voice over. There is one especially non-obvious press of the down arrow key.

We think that d/l at 4 second interval solves (really: masks) the discontinuity that occurs when the UTC - GPS time offset update is received from the GPS system.

best regards,
Evan Ludeman for CNi

--
Dan, 5J

Well, here I am in Cordele with R5S starting on Monday and got the OLC time error message after submitting my ClearNav II log for yesterday’s flight.
So, downloaded CN vario version and got the same error message. For thrills I loaded a flight on 5/15/19 and although OLC advised late, accepted the flight into the system. I have changed nothing nor updated either unit since 5/15 so why then, not now?
I will look at and change the interval to 4 secs and try again ( as mentioned by T8 in this thread).
Questions and request...
Will I have issues with scoring during the contest (winscore)?
I would appreciate if someone would post an update summary of do and don’t and ideas in a simple to grasp way that even an airline pilot might follow.
Many thanks.
R

On 5/30/19 6:01 AM, wrote:
Well, here I am in Cordele with R5S starting on Monday and got the OLC time error message after submitting my ClearNav II log for yesterday’s flight.
So, downloaded CN vario version and got the same error message. For thrills I loaded a flight on 5/15/19 and although OLC advised late, accepted the flight into the system. I have changed nothing nor updated either unit since 5/15 so why then, not now?

It's likely OLC just recently added the check for bad time records.


I will look at and change the interval to 4 secs and try again ( as mentioned by T8 in this thread).

That should work. You have 48 hrs after flight ended to delete bad data
and try again.


Questions and request...
Will I have issues with scoring during the contest (winscore)?

It's highly unlikely a program like Winscore would have have problems,
even if you turn in a log with a glitch. No reason to turn in a log
with the glitch.

I would appreciate if someone would post an update summary of do and don’t and ideas in a simple to grasp way that even an airline pilot might follow.

You can either download with the 4 second intervals, or you can turn on
your loggers early. I would wait until you get a 3D lock indication,
then add ten minutes before takeoff. You can do both if you want.

Dave


Many thanks.
R

Hi Henry,

There will be no issue with Winscore.

What's going on he

1. UTC and GPS time are not the same. The current offset is 18 seconds.

2. When the GPS starts up, it starts with an offset programmed in firmware.. This offset is less than 18 seconds.

3. After GPS lock, the GPS receiver gets the current offset from the system, typically about 5 minutes after GPS lock. It applies the new offset immediately, and the jump causes one out of sequence B record if the flight recorder is recording. It doesn't start recording until you are flying.

4. OLC picks up the out of sequence B record if it exists.

Since the offset change is 2 or 3 seconds, it can be masked by setting the igc file fix interval to 4 seconds. You can avoid the jump altogether by powering up 5 minutes before flying.

If you get a bad OLC result, you can fix it by downloading your flight again at either 4 or 10 second interval and resubmitting.

best regards,
Evan Ludeman


On Thursday, May 30, 2019 at 8:01:58 AM UTC-4, wrote:
Well, here I am in Cordele with R5S starting on Monday and got the OLC time error message after submitting my ClearNav II log for yesterday’s flight.
So, downloaded CN vario version and got the same error message. For thrills I loaded a flight on 5/15/19 and although OLC advised late, accepted the flight into the system. I have changed nothing nor updated either unit since 5/15 so why then, not now?
I will look at and change the interval to 4 secs and try again ( as mentioned by T8 in this thread).
Questions and request...
Will I have issues with scoring during the contest (winscore)?
I would appreciate if someone would post an update summary of do and don’t and ideas in a simple to grasp way that even an airline pilot might follow.
Many thanks.
R

Thanks to the brain trust for the easy to understand summary.....the sport has improved due to the smart guys.
I will save and pass on to others.
Great flights!

R

I've made two flights since experiencing the problem.Â* Since then, I've
turned on my CN devices 20 or so minutes before takeoff and have not
seen a repeat of the problem.

On 5/30/2019 6:46 AM, Tango Eight wrote:
Hi Henry,

There will be no issue with Winscore.

What's going on he

1. UTC and GPS time are not the same. The current offset is 18 seconds.

2. When the GPS starts up, it starts with an offset programmed in firmware. This offset is less than 18 seconds.

3. After GPS lock, the GPS receiver gets the current offset from the system, typically about 5 minutes after GPS lock. It applies the new offset immediately, and the jump causes one out of sequence B record if the flight recorder is recording. It doesn't start recording until you are flying.

4. OLC picks up the out of sequence B record if it exists.

Since the offset change is 2 or 3 seconds, it can be masked by setting the igc file fix interval to 4 seconds. You can avoid the jump altogether by powering up 5 minutes before flying.

If you get a bad OLC result, you can fix it by downloading your flight again at either 4 or 10 second interval and resubmitting.

best regards,
Evan Ludeman


On Thursday, May 30, 2019 at 8:01:58 AM UTC-4, wrote:
Well, here I am in Cordele with R5S starting on Monday and got the OLC time error message after submitting my ClearNav II log for yesterday’s flight.
So, downloaded CN vario version and got the same error message. For thrills I loaded a flight on 5/15/19 and although OLC advised late, accepted the flight into the system. I have changed nothing nor updated either unit since 5/15 so why then, not now?
I will look at and change the interval to 4 secs and try again ( as mentioned by T8 in this thread).
Questions and request...
Will I have issues with scoring during the contest (winscore)?
I would appreciate if someone would post an update summary of do and don’t and ideas in a simple to grasp way that even an airline pilot might follow.
Many thanks.
R

--
Dan, 5J