Cheap GPS Loggers for FAI Badges - Status?

I do not know that it is silly. On the one hand we
have a barograph which by admission is in-accurate
and requires complicated and, it has to be said, approximate
corrections and on the other hand we have GPS which
is more accurate and the corrections for which are
straightforward. My FR is also a barograph, it records
pressure altitude and the GPS altitude. Why, instead
of making a calculation to correct the pressure altitude
to geometric altitude, cannot the geometric altitude
recorded be used directly. IF not is there a cogent
argument against?

Sorry for using QFE and QNH, not the best way to describe
AMSL and AGL - I stand dejected.

At 11:24 25 May 2004, Mike Borgelt wrote:
On Tue, 25 May 2004 02:20:28 GMT, Marc Ramsey
wrote:

Eric Greenwell wrote:
How do they do this? Do they also record temperature
along with pressure
altitude?

====
Sporting Code Section 1 - Aerostats
Annex 2 - Calculation of Geometric Altitude from Barometric
Altitude:

3. Meteorological information must be obtained for
a position and
time as close as possible to that of the flight.
The surface
pressure should be obtained together with temperature
and
(optionally) humidity for a range of heights up
to the height
being measured. If the meteorological information
is not
available the air must be assumed dry, the temperature
the
coldest possible for that location and season,
and the surface
pressure the lowest that could have been possible.

4. The claimed altitude must be adjusted for the effect
of the
atmospheric data by a met hod which can be shown
to be correct.
Calculations have been accepted using the following
methods:

1) CALCULATION OF CORRECTED ABSOLUTE ALTITUDE by
Hans Akerstedt
(Version 2/95 June 1995 effective date) - a
method of manual
calculation.
2) CAMERON BALLOONS PROGRAM FOR FAI RECORDS (CBFAI
version 97.3
and later). This is a program which gives a
result which is
as precise as the data used, calculating the
atmosphere layer
by layer.
3) Direct interpolation is possible using certain
types of
meteorological data. The result must usually
be converted
from geopotential to geometric metres.

Altitude calculations are very complex and procedures
can differ
for different types of instrument and available
meteorological
data. It is recommended that specialist help be
obtained.
====

I believe they still primarily use barographs (an IGC-approved
flight
recorder is acceptable as a barograph). I don't think
they've
transitioned over to use of GPS derived geometric altitude
as of this
moment.

Marc


That's how it is done. I verified an Australian balloon
altitude
record about 8 or 9 years ago. This was done according
to the world
rules and they provided a nice worksheet to make it
easy.

It has only been 4 years since SA was turned off but
the point is that
they do reduce the data to geometric altitude. As GPS
measures this
directly it would seem to be reasonable to allow GPS
with suitable
allowance for GPS errors. These are far better known
than the pressure
errors. Just choose the level of confidence you want.
From memory the error bands in the pressure calculation
(altitude was
in excess of 30,000 feet)were quite large probably
around the 99 +%
GPS error band.
Don't forget the recorder pressure calibration is done
at room
temperature. There is no guarantee it is the same at
-20 deg C(again
from memory, the FR low temperature limit) or even
colder and in fact
outside the FR spec.

On reflection this is all too silly for words for what
is really just
trivia.

Mike Borgelt

Thanks Todd, it's a good summary about the situation.

Todd Pattist wrote:

I don't really think that the internal security breach is
the major security problem for FR's, but it is a concern. My
problem is with the general belief that an approved FR is
better than the older camera/baro/OO system.

1) The FR stores its secret number inside. It's hard to get
it out, but not impossible.

2) The FR typically uses an off-the-shelf GPS engine inside
the box. The only security between that engine and the
encryption is an aluminum case and a switch that's supposed
to go off if you open it up. You merely defeat the switch,
open the case and feed simulated digital GPS data into the
encryption system to produce a valid record.

Good point, there are several non-destructive ways to detect the place
of this switch/switches and avoid it during hacking. Inside the FR I
suspect the same serial communication between the logging part and the
pure GPS part as it's on all GPS systems (NMEA-183). Here you can inject
your fake position data with the existing sims. Some pressure hack also
needed.
Hopefully noone spends his/her freetime on it....

3) The digital record is extremely "clean" as compared to
the analog systems of old, and evidence of cheating is much
harder to detect if the encryption is valid.

4) GPS simulators are available and have already been used
to produce "valid" flight data in a secure FR for
nonexistent flights.

What do you mean with this sentence? Do you know about any case where
valid IGC file was created hacking the FR?

I'm not attacking the FR, I think it's a great system that
makes things easier for pilot and OO ... at a price ... but
that price is too high for the bottom end of the sport
where we all started and the future of the sport lies. It's
wrong to think of FR's as buying security. It's not good
enough alone for records and it's overkill for badges.

The OO has a much more important role than is recognized in
maintaining security for important flights (records) and the
existing tried and true OO system is more than sufficient
for badge flight security with a COTS recorder.

It's also true. I haven't seen any OO who checked flight declaration
before flight. For example in certain cases it's beneficial to replace
the nimbus4 with a ka8 in the declaration. Only the OO ensure that a
certain pilot did a FAI badge requirement and not only the FR traveled
in someone else's luggage compartment...

/Janos

Janos Bauer wrote:


The OO has a much more important role than is recognized in
maintaining security for important flights (records) and the
existing tried and true OO system is more than sufficient
for badge flight security with a COTS recorder.


It's also true. I haven't seen any OO who checked flight declaration
before flight. For example in certain cases it's beneficial to replace
the nimbus4 with a ka8 in the declaration. Only the OO ensure that a
certain pilot did a FAI badge requirement and not only the FR traveled
in someone else's luggage compartment...

I'm puzzled: why does the OO need to check the flight declaration before
the flight on an approved recorder? I routinely make flights where the
OO doesn't check the flight declaration before the flight, which is
allowed by the approval document for my recorder. I can change the
declaration at any time I wish. Of course, if I change it after the
takeoff, it is invalid, and this can be determined from the flight file.

He is required to ensure the flight recorder from which the flight file
is taken is the same one that was in the glider when it took off (in
other words, "maintain control" of the flight recorder through
observation or sealing to the glider).

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Eric Greenwell wrote in message ...

Only a good radar altimeter (or laser
rangefinder) is better.

You probably didn't mean that, since these are AGL measurements, not MSL.

You are right, poor/garbled syntax on my part: What I was getting at
is that lacking a GPS, the only theoretical way to get good actual
elevation would be with a Radar Altimeter or Laser over a known
elevation. Not practical in real life.

We could get into the practical differences between QFE and radar
altitude, but that's a bit of a stretch on a gliding forum! Although
with GPS and the new PDA moving map software, AGL altitude is now
becoming easy to get in a glider - amazing technology.


Kirk

"Marc Ramsey" wrote in message
om...
303pilot wrote:
I don't think I've met anyone in soaring who would cheat on a badge
flight.
What would the point be?
Badge flights are about personal accomplishment. If there is an
individual
in this sport so sad as to cheat on a badge flight, let him/her.
Record flights deserve the higher level of scrutiny because we are
comparing
performances between individuals.

So, you are an advocate of the "honor system". Nothing wrong with that,
but that is not the current intent of the FAI/IGC or its delegates...

Marc

No, I'm not in favor of the "honor system". I am in favor of pairing cheap
GPS's with declarations and OO's for badge flights.

What exactly is the "current intent of the FAI/IGC"?

What is the benefit to the sport of increasing the cost and complexity of
flight documentation for the purpose of reducing a problem (cheating) that,
so far as I'm aware, does not exist at any meaningful level? Does the
FAI/ICG believe that absent expensive secure loggers all/most/some/10% of
pilots would cheat? What is the problem that is being solved by the use of
these devices rather than simpler, cheaper devices?

Disclaimer - I own a secure flight recorder. My only interest is doing what
is most likely to enhance the sport through greater participation in XC
flight.

He knows, you know and the SSA instructor knows.
What value does the pilot get from that C badge?

"Jim Vincent" wrote in message
...
I don't think I've met anyone in soaring who would cheat on a badge
flight.
What would the point be?

I don't know about that. I know of one pilot who was earning the C badge
for
duration. He released about 500 feet higher than allowed. Then SSA
Instructor
who awarded the badge said it was "close enough".

Jim Vincent
CFIG
N483SZ
illspam

"Todd Pattist" wrote...
The report is that a GPS simulator was used to create a
valid secure approved FR position record without opening the
case by producing simulated GPS signals that the FR antenna
picks up and records as real. I believe the .igc trace was
intentionally made "unbelievable" and IIRC, did not include
a simulated pressure altitude. GPS simulators are
commercially available and cost a lot less than what many
record hunters spend to fly in the best conditions found on
this planet.

This particular story comes up sooner or later when we get one of these
threads going, but no one has ever made the .igc files available, identified
the equipment used, or named the people who accomplished it. As far as I
can figure out, generating a convincing flight log would require an 8 to 12
channel programmable simulator, a fast programmable pressure device, and a
bunch of software development. This does not strike me as something cheap
and easy to do. If it is easy, then some verifiable information, along with
suggestions as to how we can improve the system, would benefit everyone.
Otherwise, this is just so much blowing of smoke...

Marc

This is true, but anyone who sees the student wearing the badge would rightly
assume that the student actually earned it. Had I been that student, I would
have declined the badge until I rightfully earned it. Instructors like this
diminish the credibility of the SSA badge program. But this is just one data
point of many lies from that instructor.


He knows, you know and the SSA instructor knows.
What value does the pilot get from that C badge?

I don't think I've met anyone in soaring who would cheat on a badge
flight.
What would the point be?

I don't know about that. I know of one pilot who was earning the C badge
for
duration. He released about 500 feet higher than allowed. Then SSA
Instructor
who awarded the badge said it was "close enough".



Jim Vincent
CFIG
N483SZ
illspam

Dnia 5/25/04 4:48 PM, U¿ytkownik 303pilot napisa³:

Disclaimer - I own a secure flight recorder. My only interest is doing what
is most likely to enhance the sport through greater participation in XC
flight.
In my opinion, you really don't need FAI to popularise XC flights. Every
glider pilot needs 8 successful flights to reach 3 diamonds - and that's
all most pilots need certified logger for. You really don't have to own
one by yourself, few loggers bought by a club is enough for all it's
members.

Methods of flight recording in all competitions below continental level
are up to organisers. These are the people who should be convinced to
"COTS" solutions. Forget lobbing IGC, you don't need their help.

Case:
Since this year in Poland you can use almost any "GNNS flight evidence
device" in all competitions except Nationals. This also includes on-line
contests (here some limitations has been made to ensure basics of
security). All these new regulations were made on level of the national
Gliding Commision, without any consulations with IGC.


--
Wojtus'.net __|__
FidoNet: 2:484/47 `--------o--------'

"Todd Pattist" wrote...
"Marc Ramsey" wrote:
As far as I
can figure out, generating a convincing flight log would require an 8 to
12
channel programmable simulator, a fast programmable pressure device, and
a
bunch of software development.

Why 8-12 channels? Spirent sells a 6-channel GPS simulator
with programmable capability.

There is the required satellite constellation (F) record. It would be
pretty easy to figure out something was wrong if no more than 6 satellites
were ever visible at a time.

You seem to think my comments are aimed at denigrating
security of FR's. They aren't. I think FR's are secure
enough. The last thing I want is even more expense in the
name of security.

No, my point was simply that it is easy to claim that someone once used a
GPS simulator to create an IGC file, but no one has ever thought it worth
their while to provide specific details to the IGC, GFAC, or anyone else.
Flight recorder security isn't there just to annoy people, it is there
because at least some portion of the community think it desireable to make
it difficult to forge flight evidence. Those who wish to bring about change
need should be willing to provide some evidence to back up their arguments.

My comments are simply intended to paint the security we
have in a realistic light and to emphasize that we still
rely on the OO for world record security where the
motivation to cheat is greatest. I think we should also be
able to rely on OO security for badges using a COTS GPS
where the stakes are far lower if someone should actually
cheat.

Agreed.

Marc