GPS interference and contests

It seems as if GPS interference testing is becoming more widespread.
See: http://www.navcen.uscg.gov/gps/gpsno...terference.pdf

I wonder if anyone has thought of what might happen if one of these 'tests'
happened near the time an place of a sechduled contest. Basically, you
would lose all GPS systems including loggers. Back to photos? Anyone
thinking about contingencies?

Bill Daniels

Bill Daniels wrote:
It seems as if GPS interference testing is becoming more widespread.
See: http://www.navcen.uscg.gov/gps/gpsno...terference.pdf

I wonder if anyone has thought of what might happen if one of these 'tests'
happened near the time an place of a sechduled contest. Basically, you
would lose all GPS systems including loggers. Back to photos? Anyone
thinking about contingencies?

This schedule covers days when someone thinks they might want to run a
test, in practice, there are somewhat fewer live tests. The contest
staffs here check NOTAMs daily, if there is notice of a test, they'd
task away from the affected area, or cancel the day if not possible.

I have an IGC file (which I'd be hard pressed to find) from a day when
there was a NOTAMed test at China Lake (roughly 200 miles to the south
of my location), not much to see, except for a few gaps of a couple of
minutes each...

Marc

On Jan 17, 9:28 am, Marc Ramsey wrote:
Bill Daniels wrote:
It seems as if GPS interference testing is becoming more widespread.

As Marc noted, China Lake have been conducting these tests for a
while. It started out mostly on weekdays, bur Saturdays are possible
too.
Several of us have logged flights with holes in them, some quite
large. It does not put a hole in the pressure altitude trace, but may
eliminate your turnpoint. That's the only concern.
One flight last year I was able to campare notes with pilots flying
out of Minden, while I was just North of China Lake. The Minden pilots
had no interference, but my signal was really broken up. The Cambridge
gear seemed to come online rapidly afterwards, but WinPilot had to be
restarted to give me any useful information (I knew the winds were not
at 80 or 90 knots for example)
Watching these logs on SeeYou is interesting. The glider stops,
hovers up and down for a while, then shoots forward 5 miles or so.
Jim

On Jan 17, 2:25*pm, JS wrote:
On Jan 17, 9:28 am, Marc Ramsey wrote:

Bill Daniels wrote:
It seems as if GPS interference testing is becoming more widespread.

* As Marc noted, China Lake have been conducting these tests for a
while. It started out mostly on weekdays,

Bill and all,

Yes, this has been reality in the US for several years.
I managed to warn the 1-26 Nationals about 3 seasons ago, when they
faced blanking/testing for their national contest from Moriarty, NM.
I offered guidance for conversations, and they worked wtih the staff
at
White Sands to adjust the local tests to be prior to launch/flight/
task times.
Otherwise, you are right. Achieving turns could only have been
verified by cameras, again.

I raised the discussion to IGC level, about the possibility of world
record attempts
(which are possible from my site) having pre-launch authorization
possible for
antiquated validation/recording devices ( analog equipment!), but was
pooh-poohed as not having an authentic concern. At that point in
time,
we were hosting the Perlan glider with Fossett/Enevoldsen and it
was a VERY real concern for us. And it still is.

We are fortunate to have a close working relationship, and know on
any given week if jamming will occur for the following calendar week,
locally. It adds to the flight planning considerations.
I can have world class weather, military airspace permission and IGC
approved recording devices, and have a data file that is worthless
for
record documentation.

So, yes, we have tried for contingency planning. They work, within
the US.
And yes, your SSA airspace and technical folks ARE trying to serve
glider pilot interests in the larger sense.

Cindy Brickner
Region 12 Director
SSA Airspace Committee

On Jan 17, 7:53 pm, CindyB wrote:
I raised the discussion to IGC level,
snip
I can have world class weather, military airspace permission and IGC
approved recording devices, and have a data file that is worthless
for
record documentation.

So, yes, we have tried for contingency planning. They work, within
the US.
And yes, your SSA airspace and technical folks ARE trying to serve
glider pilot interests in the larger sense.

Cindy Brickner

Is it worthwhile for us to keep carrying cameras and barographs to
have ammunition that might convince IGC that this IS an authentic
concern? Or maybe ask the Navy to jam GPS near a European contest? :-
P

I agree, the baro part of the logger SHOULD be uninterrupted, making
the more painful camera operations critical in showing the case to
IGC.

I hope that we're not becoming "Logger Cripples" (unable to function
without GPS, Logger, SeeYou, etc.). I'm planning to keep flying with
my backup Replogle and camera -- but then I'm semi-old-fashioned and a
1-26 driver (some read that "masochist"). Isn't the chief function of
the camera to validate rounding the turnpoint (second being
documenting the declaration)? Several years ago, the 1-26 Association
Sweepstakes did away the requirement that turnpoints be "photo
friendly" (i.e., the turnpoint had to be a feature that could be
recognized by photo, leveling the playing field for those that used
cameras instead of GPS's). Similarly, it was just recently that the
1-26 Championships REQUIRED GPS for the contest, mainly in a bid to
reduce the costs (both time and money) generated by film development.
Years ago, my camera & barograph saved my Diamond Goal flight when I
fat-fingered an error in the lat-lon of the first turnpoint for the
logger declaration (though I'd still whine about the Volkslogger's
"comfortable DOS interface").

Many contest and world class pilots have recommended carrying TWO
loggers, for the eventual day when one of them fails. Unfortunately,
in the Jammed GPS environment, one "failure" would render both loggers
unusable (especially at the turnpoint). We as pilots should be able
to see this -- matching the out the window expectation with the GPS
indicated arrival of the turnpoint.

Even though I'm a 1-26'er, I enjoy the training and entertainment
value of loggers and software...and the compelling and "crippling"
moving map display on the PDA. As the seminar title suggests, "help,
my GPS sucked my brains out!"

Thanks for carrying the torch to IGC, even if they're pooh-poohing the
issue.

-Pete
#309

309 wrote:
Is it worthwhile for us to keep carrying cameras and barographs to
have ammunition that might convince IGC that this IS an authentic
concern? Or maybe ask the Navy to jam GPS near a European contest? :-
P

I'm curious, what exactly are you expecting the IGC or anyone else to
do? Are you really carrying a camera just in case someone randomly
decides to run a jamming test while you're in the midst of a world
record attempt?

Marc

On Jan 20, 2:31 pm, Marc Ramsey wrote:
I'm curious, what exactly are you expecting the IGC or anyone else to
do? Are you really carrying a camera just in case someone randomly
decides to run a jamming test while you're in the midst of a world
record attempt?

Marc

I am trying to complete my third diamond, for distance, in my 1-26.

Last I heard, the SSA still (for another year?) will award badges/
diamonds with camera and photo documentation.

I mainly fly in the Owens' Valley, which has been subject to at least
a NOTAM indicating that the Navy might jam GPS for each and every day
I've been able to soar there in the last 3 years. They're not random
about it at all. No, I'm not convinced that the Navy is angry with me
over something I did to them -- but that doesn't mean they aren't
angry with me...

FWIW, each of my previous diamond flights set Regional 1-26 Class
records (absolute altitude & gain of altitude in one, and speed over a
300 km closed course for the other). I did not have an IGC logger
aboard for the altitude flight. For the speed record (since shattered
by 1-26 Legend Doug Levy) probably would not have been possible
without GPS.

That third diamond is my secondary focus in any and all of my soaring
activities. Having fun (safely) is my primary objective.

I find it odd that IGC (and soon SSA) have chosen to recognize only
the latest technology for documentation, especially considering that
very few submissions go in "the old fashioned way." Is it laziness?
Both IGC and SSA push the lions' share of responsibility onto the
Official Observer for validating claims and achievements. How
difficult is it to look at the picture, ESPECIALLY given the
popularity of tools that help OO's and IGC do this easily (e.g.,
Google Earth)???

Slightly off topic, all the politics notwithstanding, I really admire
Dennis Wright for getting his silver distance the REALLY HARD way,
flying a 1-26, off of an auto-tow launch, with a honkin' headwind on
the return leg of a declared out and return. Double
Tough...especially considering he could have put on a glass slipper
and damn near coasted.

There have been other threads suggesting that IGC revise the diamond
criteria to take account of glider performance. It would seem to me
that this would be a much higher priority for IGC if you consider the
fact that when the original diamond criteria were conceived, a 30:1
ship wasn't even in anybody's DREAMS. Though I sound bitter, I'm glad
they've left those traditions alone.

If a simple disposable camera can be used with a declaration form to
save a diamond (or in somebody else's case, a world record) from the
Navy's penchant for jamming GPS, then I'm all for it (using cameras
that is, not jamming).

Thanks for starting the topic (again?), Bill.

-Pete
#309

snip
I have an IGC file (which I'd be hard pressed to find) from a day when
there was a NOTAMed test at China Lake (roughly 200 miles to the south
of my location), not much to see, except for a few gaps of a couple of
minutes each...

Marc

One of my former students was flying to an airport in the China Lake
area and navigating primarily by GPS during one of the Notamed times.
He had noted the Notam but didn't think much of it until the GPS
showed him as arrived and there was no airport. After fumbling with
the map for a few minutes he figured out the airport was about 5 miles
away from where the GPS said it was.

Brian
CFIIG/ASEL

Big problem is proving that you didn't break airspace...

Very hard to do with a camera & barometer!

Even though this thread is related to GPS jamming affecting contest
flight documentation, please allow me this little rant.

GPS navigation is now fully accepted in the US and there are even some
instrument approaches based upon GPS.

Now I ask, NOTAMS or not, why should it be legal for ANYONE to jam a
system which is used in air navigation? Pilots who are fortunate not to
live/fly near a military installation who jam these signals can enjoy
the system. The rest of us have to put up with unreliable/intermittent use.


Is this an issue that the AOPA and the SSA should try to address?


Paul




Bill Daniels wrote:
It seems as if GPS interference testing is becoming more widespread.
See: http://www.navcen.uscg.gov/gps/gpsno...terference.pdf

I wonder if anyone has thought of what might happen if one of these 'tests'
happened near the time an place of a sechduled contest. Basically, you
would lose all GPS systems including loggers. Back to photos? Anyone
thinking about contingencies?

Bill Daniels