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mccordia

US Performance Competition - Acro Invitational (November 2011)

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was there a GPS repetitor inside the plane (like a relay antenna) ?
we had that even in the Porter for the trackingderby competitions



It could be but is that really needed? Modern GPS devices are capable to make a hot-start in 1s. You suppose to start and get a signal lock on the ground before boarding. Your device should be able to get signal lock in 1sec after your exit.

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The Flysights have been used at numerous European competitions without issue, as far as i know being in the US shouldn't change anything (unless there is a military facility in the vicinity of Elsinore?)

What exactly were the problems / errors encountered? Spiky data? Between Michael, LukeH, Klaus, Kallend, LouD and all the other techies that read this forum we should be able to sort it out for the sake of the next US event.

DSE could you post one of the faulty .csv files? (as this shows the # of satellites, accuracy etc)
BASEstore.it

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What exactly were the problems / errors encountered? Spiky data? Between Michael, LukeH, Klaus, Kallend, LouD and all the other techies that read this forum we should be able to sort it out for the sake of the next US event.



Yes let´s take this opportunity and figure out what could help preventing this major problems on further events.

I checked the RAIM Status Reports (forecasts and actualls) for that day that our airline uses and there was no issues with the sattelites reported. so the problems must have been somewhere else.

on most of the competitions i have competed in wintec gps were used and we experienced barely any problems. maybe its flysight related?

@lurch: sorry i said jarno was third in speed. i was just reminded that you were but i got confused with the unsorted data here on the ppc website.

http://www.paralog.net/ppc/showevent_compact.php?event=U.S.%20Performance%20Cup%202011

i guess the organizers are working on it to present the results any minute.
You see things; and you say, 'Why?' But I dream things that never were; and I say, "Why not?"

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The units used are the same ones used in Hungary, Gransee, Holland etc for other competitions, and used the exact same way.

Regardless of placement, switch on (they all aquired signal on the ground first) they didnt aquire a fix untill 30 to 40 seconds after exit, or often not at all. The graphs showed insane spikes of up to 4000 kmh forward, glide up to 9:1 (without dive/flare) and freefall times of nearly 2 mins within the altitude window in some extreme cases.


The graphs showing no spikes, no weird peakdata (insane glide preceding without dive/flare etc) where the only onrd used in scoring the final results. Luckely it was a pretty obvious thing to see in the results, as also Klaus confirmed over skype with Lurch files sent to him as an example.
JC
FlyLikeBrick
I'm an Athlete?

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I brought up the subject of implementing a repeater in the plane while we started having the problems. Issue with this is that it would have to be a very specific antenna to broadcast the band in which the GPS transmitter operates on.

Has anyone look at pure logistics and terrain in this area before? You have a valley that is approx. 1,247 from sea level and Mountains at each side that peak at approx. 3,500 feet in the West and 2,300 on the Northeast. That’s approx. 4,747 feet in the West of DEAD SPACE and 3,547 feet in the Northeast.

The particular terrain in the Lake Elsinore area could potentially create a funnel in which a Clear Point of Sight to obtain a GPS signal might not be possible if the satellite isn't directly over the area. At a rate of one rotation around the earth every 12 minutes I wouldn’t see a problem, but if there was maintenance being conducted by our friends in Gov. this could possibly minimize the availability of GPS signaling. Just food for thought.

On my drive back to LAX from Lake Elsinore on Monday morning, my phone didn’t actually get a GPS signal until I left the mountain terrain and came to close proximity of LA away from elevation.
~Migs~

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Regardless of placement, switch on (they all aquired signal on the ground first) they didnt aquire a fix untill 30 to 40 seconds after exit



sounds like they were unable to aquire a signal as long as they were not outside under clear sky.normally its not a problem to aquire a signal in a plane.of course there are different qualitys in gps. while my cheap garmin car gps never gets a signal in any building my better (and more expensive) one which is used for climbing and hiking in mountains easily picks up a signal in my house.

thats why i am thinking (and its just a guess) that there are maybe more reliable gps out there for the job. they might have worked on previous events, but they , lets put it this way, were obviously at least "involved" in this disaster.

so where are you at right now with the troubleshooting? whats your guess what happened?
final results and ranking coming up soon on the ppc webpage?
You see things; and you say, 'Why?' But I dream things that never were; and I say, "Why not?"

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Here is more food for thought folks Provided by NAVCENT/US Coast Guard:

TEST PERIOD APPROVED BY DEPARTMENT OF DEFENSE JOINT CHIEFS OF STAFF.
TEST LOCATION
EXACT DATES AND TIMES OF TESTING, DURING APPROVED PERIOD, WILL BE DETERMINED BY TEST RANGE EVENT PLANNERS.
GPS NAVIGATION SIGNAL WILL BE UNRELIABLE
WITHIN A: xxx NM Radius of Position


China Lake, CA
(CHLK 11-13)
07 NOV 11 - 16 DEC 11 (Dates/Distance are Approximate)
100 NM RADIUS OF POSITION:
36 09 18N; 117 37 32W
~Migs~

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Just for FYI:

I used my Flysight last Febuary for about 5 performance runs at Elsinore when I first got it and never had a problem. Actually I never have had a run not record in the 6 months I used the Flysight before I went on my vacation to Afghanistan. Also, Spot occasionally uses his Flysight and as far as I know never had an issue. It likely has to be a "freak" non-consistant occurance based on past use of the Flysight unit at the same location. I guess for the next competition other GPS units could be present to prove there is an issue with the Flysight units if the same issues come about, but I think it is unlikely.
Base# 1638

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Here is more food for thought folks Provided by NAVCENT/US Coast Guard:

TEST PERIOD APPROVED BY DEPARTMENT OF DEFENSE JOINT CHIEFS OF STAFF.
TEST LOCATION
EXACT DATES AND TIMES OF TESTING, DURING APPROVED PERIOD, WILL BE DETERMINED BY TEST RANGE EVENT PLANNERS.
GPS NAVIGATION SIGNAL WILL BE UNRELIABLE
WITHIN A: xxx NM Radius of Position


China Lake, CA
(CHLK 11-13)
07 NOV 11 - 16 DEC 11 (Dates/Distance are Approximate)
100 NM RADIUS OF POSITION:
36 09 18N; 117 37 32W



After doing a Radius measurement from China Lake to Lake Elsinore... it is only 23 NM outside of the testing range. This is very possibly that this was the cause of all the signal conflicts over the weekend.
~Migs~

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on most of the competitions i have competed in wintec gps were used and we experienced barely any problems. maybe its flysight related?



I have seen that the Wintec was used a lot in the past and have no idea if this would have offered a different result? Separate from if it would have been different, It brings up an interesting question though as to what advantage that the Flysight offers? Having not looked into them much since I don't own either unit, my only perception of the difference is that the Flysight can offer audible signals to provide performance feedback real time during a flight. I think it can even give directions to a waypoint, though that is being beta tested I hear. There might be more to it but is the data outputted to paralog the same?

The event was fun and I think the organizers did a good job dealing with the technical issues. It was great to see a lot of old and new friends and I look forward to another opportunity to participate in an event like this....

Scott C.
"He who Hesitates Shall Inherit the Earth!"

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"In this event, to prevent cheating etc the flysights where provided by the organization, and hence giving a 0 for no data or inaccurate data is a little harsh in my opinion.. "

Why so? What else could they possibly do, cancel the whole thing?
-B



No, but at USPA Nationals you get a rejump if the error was not something you caused.. And in RW there need to be at least a certain number of valid rounds by all teams to call the competition, and indeed if these minimum requirement are not met, there simply is no winner, but I don't beleive this ever happened.

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GPS NAVIGATION SIGNAL WILL BE UNRELIABLE
WITHIN A: xxx NM Radius of Position

China Lake, CA
(CHLK 11-13)
07 NOV 11 - 16 DEC 11 (Dates/Distance are Approximate)
100 NM RADIUS OF POSITION:
36 09 18N; 117 37 32W



After doing a Radius measurement from China Lake to Lake Elsinore... it is only 23 NM outside of the testing range.



What do you think LouD?
BASEstore.it

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Here is more food for thought folks Provided by NAVCENT/US Coast Guard:

TEST PERIOD APPROVED BY DEPARTMENT OF DEFENSE JOINT CHIEFS OF STAFF.
TEST LOCATION
EXACT DATES AND TIMES OF TESTING, DURING APPROVED PERIOD, WILL BE DETERMINED BY TEST RANGE EVENT PLANNERS.
GPS NAVIGATION SIGNAL WILL BE UNRELIABLE
WITHIN A: xxx NM Radius of Position


China Lake, CA
(CHLK 11-13)
07 NOV 11 - 16 DEC 11 (Dates/Distance are Approximate)
100 NM RADIUS OF POSITION:
36 09 18N; 117 37 32W



After doing a Radius measurement from China Lake to Lake Elsinore... it is only 23 NM outside of the testing range. This is very possibly that this was the cause of all the signal conflicts over the weekend.



So far the most plausible explanation, although we were competing on the 5th of november.. Any way we can contact these guys and get them to confirm they were testing last weekend?

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I've got easily 100 jumps with the Flysight at Elsinore, and this is the first time it's been any kind of issue.
On Mon, Tues, Wed (yesterday) I jumped with two and three units, stored in my pant pocket, neck bag, and stocking. No issues presented themselves, and the units weren't powered up until we were doing the 10K gear check (they'd been powered up on the ground).
GPS access in this area is generally pretty good on my Droid, although there are places near the pass and of course at the mouth of the Ortega highway where it's not visible.

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Here is more food for thought folks Provided by NAVCENT/US Coast Guard:

TEST PERIOD APPROVED BY DEPARTMENT OF DEFENSE JOINT CHIEFS OF STAFF.
TEST LOCATION
EXACT DATES AND TIMES OF TESTING, DURING APPROVED PERIOD, WILL BE DETERMINED BY TEST RANGE EVENT PLANNERS.
GPS NAVIGATION SIGNAL WILL BE UNRELIABLE
WITHIN A: xxx NM Radius of Position


China Lake, CA
(CHLK 11-13)
07 NOV 11 - 16 DEC 11 (Dates/Distance are Approximate)
100 NM RADIUS OF POSITION:
36 09 18N; 117 37 32W



After doing a Radius measurement from China Lake to Lake Elsinore... it is only 23 NM outside of the testing range. This is very possibly that this was the cause of all the signal conflicts over the weekend.



So far the most plausible explanation, although we were competing on the 5th of november.. Any way we can contact these guys and get them to confirm they were testing last weekend?



Here is the contact link and numbers:
http://www.navcen.uscg.gov/?pageName=gpsUserInput

Also, scheduled testing:

http://www.navcen.uscg.gov/pdf/gps/gpsnotices/GPS_Interference.pdf
~Migs~

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I know you had Klaus from Paralog involved all the time. I recently tried to download a week's data from Lodi, Hollister and Elsinore into Paralog and had a lot of failures (about 50% or more) although I had clear audible feedback and green light on the FlySight during the jumps. When looking at the files with Explorer they showed reasonable size and table data but Paralog still would not accept them. Just saying, not wanting to blame the Flysight-Paralolg link.

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You're right, one reason for it. And KrisflyZ: yes, blinking.

Edit to add: How many of you have turned off the FlySight while under canopy, turning off the camera also because you knew that of the 16GB space a lot was used already and you have had so many landings filmed already? I have, I admit it and I know there's a lot out there that I know not yet!

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@Sam: No offense taken. I'm not so prickly or ego reliant that I can't stand having somebody misquote how well I did. In 2 years' time, who's going to remember anyway? It was just a Bronze. Looks good on my wall. I'm happy with it.

Re: trouble:
I'm thinking most likely its that DOD testing thing.
Things I noticed:

1: In Gransee we powered each unit up until blinky light right before getting in the plane, shutting it off, then restarting at 9k. No jumps were lost, I got green blinking every time, -in- the plane regardless of where in the plane it was. I know the things were ground tested here but I don't think anyone was following that exact procedure to start. When my first data dump got nothing, I started doing this. One jump later I started getting results... may be just coincidence, maybe not. May just be they quit the interference-causing activity at that time. No way to tell.

2: Last jump I kept the GPS turned on all the way up and physically held to the window most of the ride up and watched it. I don't think mountains had anything to do with problem... I had green blinky for most of the ride, then in the last 3000 feet of the climb it began blinking erratically, visibly gaining and losing satellite lock every few seconds. Window view or not, it did it.
Joel was sitting opposite side of plane from me. He had two, both working fine, and offered one to me since it looked like mine was about to conk out entirely. When I reached over to his side of the plane, (left/pilot side) I had mine in hand, and as long as I held it in the same space Joel and Robi were occupying on that side of the plane the erratic blinking stopped and mine worked as well.
I ended up physically holding my wing with both GPS's in it, (one in wing pocket one dropped into wing root) into the left half of the plane's interior so they could get a view out the left windows in the last minutes before exit. Result: Both units worked and recorded roughly the same track. I didn't look at it myself but when Jarno checked em he said they both got stuff and the stuff agreed with each other.

What I'm thinking is either busy/tested satellites making the devices selectively directional, or just the interference itself chewing up the signals on us in-flight.

The jump runs were awesome on this, naturally straight lines home. After every window, from 6000 feet on down was enough time to pull some nice long planeouts and run home. Those post-window planeouts were MUCH longer than the period on the ground in which I was booting the unit and making sure I had a lock. I had units inside my wing where in-flight they had a huge wide view of the sky for as long as they could have wanted. By all logic, even IF they had no lock when I exited, they should have long since got a perfect lock in midflight. Above the mountains, zero obstacles, nothing in between it and sky except 2 layers of nylon fabric. And still, I got nothin till second half of the comp.

Personally I'd put money on Migs' contribution, this DOD notification. Our stuff was getting chewed up in midflight. There was stuff we did differently than Gransee, (exit order, timing, number of jumps per run, whether or not each unit was pre-booted right before boarding) but none of that should have made squat for a difference 45 seconds after exit. But some of us all our stuff was completely wiped out. I'd bet if we held the comp today everything'd work fine. Seems kinda open and shut case to me... DOD says "we're fucking with it and it'll be unreliable today" and it was.

We were on the edge of their interference zone and I bet we got a good dose of it. I wouldn't be surprised if my directional observations in the plane actually meant that when I was holding the GPS to the pilots side, the bulk of the plane was shielding the device from some of the interfering signal. Maybe they were generating a lot of HF radio noise with some high energy multibilliondollar killer whizbang. The DOD is known to have a lot of such toys. China Lake wouldn't happen to be roughly due north or due south of us would it?

Anyway my bet is, we get no such issues with future comps unless the DOD happens to have issued such a notice that day, too.
-B
Live and learn... or die, and teach by example.

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China Lake wouldn't happen to be roughly due north or due south of us would it?

Anyway my bet is, we get no such issues with future comps unless the DOD happens to have issued such a notice that day, too.
-B



123 NM Northeast of Lake Elsinore.
~Migs~

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Here is more food for thought folks Provided by NAVCENT/US Coast Guard:

TEST PERIOD APPROVED BY DEPARTMENT OF DEFENSE JOINT CHIEFS OF STAFF.
TEST LOCATION
EXACT DATES AND TIMES OF TESTING, DURING APPROVED PERIOD, WILL BE DETERMINED BY TEST RANGE EVENT PLANNERS.
GPS NAVIGATION SIGNAL WILL BE UNRELIABLE
WITHIN A: xxx NM Radius of Position


China Lake, CA
(CHLK 11-13)
07 NOV 11 - 16 DEC 11 (Dates/Distance are Approximate)
100 NM RADIUS OF POSITION:
36 09 18N; 117 37 32W



This could very well be the reason and would fit my suspicion of jamming.

This could also explain why the units worked on side of the plane and not on the other. Was this maybe the side pointing to Crystal lake?

[Edit: From what Lurch describes (Signal was lost on the way up and re-aquired ont the way down): Is it possible the mountains were actually shielding the jamming signal?]

Does anyone know what kind of tests were performed? From the description it definitly sounds like jamming tests. Maybe someone wants to let the Army know how succesful they were? ;-)

FYI - the same units have worked flawlessly before without repeaters (which are absolutely unnecessary in normal jump planes like Otters, SkyVans, Caravans, etc.) and AFAIK Spot used the FS in Elsinore before without any problems as can be seen on PPC.

On the comments that there might be better units out there I think I can speak for Michael when saying the FS has the most modern receiver available on the consumer market: a u-blox 6 module.

@Sam [Edit: Mig]: Is there a public link for thess outage informations? Might be worthwhile to put it up on PPC... [Edit: - I see it's already up there]

Klaus

[Edit: 150nm from the Elsinore to the coordinates given]
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