Cheap GPS Loggers for FAI Badges - Status?

Marc or others,

As I've dug deeper into this subject, the issue of geometric altitude
appears to be one of the true obstacles to the adoption of COTS units. Is
there a public record anywhere of specifically what objections the "members
of the IGC, or even GFAC" have raised? In doing just some basic research
(along with the help of a major instrument manufacturer) it became pretty
obvious that geometric altitude is the way to go at this stage.

Regards,

Erik Mann


"Marc Ramsey" wrote in message
. com...

My is opinion is (and has been for years) that the IGC should switch
over to using geometric altitude, which would allow use of GPS-derived
altitude with appropriate error bars. But, my opinion is not that of
the majority of members of the IGC, or even GFAC, at this point.

Marc

Papa3 wrote:
Marc or others,

As I've dug deeper into this subject, the issue of geometric altitude
appears to be one of the true obstacles to the adoption of COTS units. Is
there a public record anywhere of specifically what objections the "members
of the IGC, or even GFAC" have raised? In doing just some basic research
(along with the help of a major instrument manufacturer) it became pretty
obvious that geometric altitude is the way to go at this stage.

Regards,

Erik Mann


"Marc Ramsey" wrote in message
. com...

My is opinion is (and has been for years) that the IGC should switch
over to using geometric altitude, which would allow use of GPS-derived
altitude with appropriate error bars. But, my opinion is not that of
the majority of members of the IGC, or even GFAC, at this point.

Marc


Suppose that one switches to "geometric altitude". What about people
who used to document their flights with barogaphs? Here all clubs have
barographs and lend them to the pilots when necessary. Hence the cost is
nil, which is certainly cheaper than the cheapest GPS.




--

Michel TALON

So far you seemed to be the most competent in the GFAC team, who else
think different than you and what are the reasons behind such an
opinion? Can we involve him/her in this open discussion?
Maybe that member should visit an average club and see how these
barographs and barograms are treated...

/Janos

Marc Ramsey wrote

My is opinion is (and has been for years) that the IGC should switch
over to using geometric altitude, which would allow use of GPS-derived
altitude with appropriate error bars. But, my opinion is not that of
the majority of members of the IGC, or even GFAC, at this point.

Michael,

Good point. I'll add it to the list of "issues to be resolved". My gut is
that for Silver/Gold badge flights a barogram could be an acceptable means
of altitude verification in combination with camera (if distance is
involved), as long as that method of validation continues to be supported by
the IGC.

In terms of the cost being "nil", at some point the barograph has to be sent
to an approved facility for recalibration, no? Around here, that sets us
back around $40. So, there is a recurring cost, whereas the GPS cost is a
one-time event.

P3

"Michel Talon" wrote in message
...
Papa3 wrote:
Marc or others,

As I've dug deeper into this subject, the issue of geometric altitude
appears to be one of the true obstacles to the adoption of COTS units.
Is
there a public record anywhere of specifically what objections the
"members
of the IGC, or even GFAC" have raised? In doing just some basic
research
(along with the help of a major instrument manufacturer) it became
pretty
obvious that geometric altitude is the way to go at this stage.

Regards,

Erik Mann


"Marc Ramsey" wrote in message
. com...

My is opinion is (and has been for years) that the IGC should switch
over to using geometric altitude, which would allow use of GPS-derived
altitude with appropriate error bars. But, my opinion is not that of
the majority of members of the IGC, or even GFAC, at this point.

Marc


Suppose that one switches to "geometric altitude". What about people
who used to document their flights with barogaphs? Here all clubs have
barographs and lend them to the pilots when necessary. Hence the cost is
nil, which is certainly cheaper than the cheapest GPS.




--

Michel TALON

Marc Ramsey wrote:
Graeme Cant wrote:

I've heard no reason whatsoever why a GPS in a lunchbox is any
different from a sealed barograph. Of course it would be possible.
So I'm puzzled why it doesn't happen. My guess is it's as much to do
with WHO's telling me it can't be done as it is to WHY.

You are focused on imagined draconian security requirements (which are
actually rather minimal for badge-only flight recorders), and glossing
over the major objection.

It only takes a few small requirements to make an OTS recorder unusable
for soaring. I see the aim as being to be able to use OTS equipment
straight out of the box. Some years ago in Oz, protectionist car
"safety" requirements for IIRC only tail lights and wipers made the
importation of most European cars almost impossible. It doesn't take
much to stymie things.

...snip...
My opinion is (and has been for years) that the IGC should switch
over to using geometric altitude, which would allow use of GPS-derived
altitude with appropriate error bars. But, my opinion is not that of
the majority of members of the IGC, or even GFAC, at this point.

Yes, Marc, I picked up your opinion earlier - and its loneliness! So,
next question, WHY don't the majority accept the change? Wide use of
OTS recorders would be enormously useful to gliding. I can't see any
technical objection to a parallel altitude standard being available for
badges and comps. I can see there may be a comparability problem for
records but that could be worked on after a geometric standard was
established and in use.

That's why I'm getting curious about the politics of these
organisations. As Sherlock Holmes said - when all other explanations
are eliminated, what remains is the truth. There has to be a political
problem because the technical ones commonly turn out to be actually
willpower.

Graeme.

Michel Talon wrote:

Suppose that one switches to "geometric altitude". What about people
who used to document their flights with barogaphs? Here all clubs have
barographs and lend them to the pilots when necessary. Hence the cost is
nil, which is certainly cheaper than the cheapest GPS.

Have a parallel standard. Use whichever you want. You just have to use
the same one throughout the flight (to state the obvious, I guess).

I see no problem with badge flights since they're not compared to other
flights which might use the other standard.

Graeme.

Janos Bauer wrote:
So far you seemed to be the most competent in the GFAC team,

It has nothing to do with competence. I agree with some of your
opinions, others do not.

who else think different than you and what are the reasons
behind such an opinion?

Tradition is a big factor. The perceived (but not adequately studied,
in my opinion) inaccuracy of GPS altitude is another.

Can we involve him/her in this open discussion?
Maybe that member should visit an average club and see how these
barographs and barograms are treated...

It doesn't matter how they are treated, as long as they can be
successfully calibrated within the set interval. The corrected pressure
altitudes taken from a barogram may be off by a hundred feet or so, but
they still provide a more accurate measurement of the precise form of
altitude required by the current IGC rules, than any COTS GPS.

Marc

Marc Ramsey wrote:
Janos Bauer wrote:

So far you seemed to be the most competent in the GFAC team,


It has nothing to do with competence. I agree with some of your
opinions, others do not.

I mean, you usually aware of the technical background (security, GPS
issues, etc-etc). On the other hand you often refuse certain suggestions
referring to existing rules and not to technical problems.

who else think different than you and what are the reasons

behind such an opinion?

Tradition is a big factor. The perceived (but not adequately studied,
in my opinion) inaccuracy of GPS altitude is another.

I also haven't really studied it but last Sunday it was the second
time when I had to fly xc without variometer and I was happy with the
simple GPS (no WAAS etc.) based palm&soaringpilot combo. I think it
would be impossible if there was really huge error (bigger than on those
20 year old barographs).

Can we involve him/her in this open discussion?
Maybe that member should visit an average club and see how these
barographs and barograms are treated...


It doesn't matter how they are treated, as long as they can be
successfully calibrated within the set interval. The corrected pressure
altitudes taken from a barogram may be off by a hundred feet or so, but
they still provide a more accurate measurement of the precise form of
altitude required by the current IGC rules, than any COTS GPS.

I don't think they are calibrated for all the temperatures. I don't
think all the mechanical impacts can be handled by calibration (I myself
(saw others do it few times) locked out the needle of one old smoky
barograph and we had to bent it back to working position, how do you
handle such an "impact"?) And the most important issue, what I stated
befo neither barographs nor cameras are sealed by OO on most of the
places I visited...
No one wants to cheat with them, it's just the way things going on
some (maybe most) places.

/Janos

Janos Bauer wrote:
Marc Ramsey wrote:
It has nothing to do with competence. I agree with some of your
opinions, others do not.

I mean, you usually aware of the technical background (security, GPS
issues, etc-etc). On the other hand you often refuse certain suggestions
referring to existing rules and not to technical problems.

So, I must not be truly competent 8^)

Tradition is a big factor. The perceived (but not adequately studied,
in my opinion) inaccuracy of GPS altitude is another.

I also haven't really studied it but last Sunday it was the second time
when I had to fly xc without variometer and I was happy with the simple
GPS (no WAAS etc.) based palm&soaringpilot combo. I think it would be
impossible if there was really huge error (bigger than on those 20 year
old barographs).

You are comparing apples to oranges. GPS measures geometric altitude
with a typical error of, say, +/- 50 feet. Barographs measure
calibrated pressure altitude with a typical error of, say, +/- 50 feet.
GPS altitude can not be corrected to pressure altitude with reasonable
error bounds, unless specific meteorological data is provided for the
time and place of the flight. Pressure altitude can not be corrected to
geometric altitude with reasonable error bounds, unless specific
meteorological data is provided for the time and place of the flight.
Without making these meteorological corrections, geometric and
calibrated pressure altitude can differ by as much as 1000 feet for a
Diamond altitude gain.

It doesn't matter how they are treated, as long as they can be
successfully calibrated within the set interval. The corrected
pressure altitudes taken from a barogram may be off by a hundred feet
or so, but they still provide a more accurate measurement of the
precise form of altitude required by the current IGC rules, than any
COTS GPS.


I don't think they are calibrated for all the temperatures.

There is no requirement that barographs be corrected for temperature.

I don't think all the mechanical impacts can be handled by calibration
(I myself (saw others do it few times) locked out the needle of one
old smoky barograph and we had to bent it back to working position,
how do you handle such an "impact"?)

That barograph should have been marked as potentially faulty. An OO, if
aware of this, should refuse to certify a flight using it until it is
repaired and recalibrated.

And the most important issue, what I stated
befo neither barographs nor cameras are sealed by OO on most of the
places I visited...

The Sporting Code requires sealing the barograph, but not necessarily
the cameras (SC3 4.6.3, 4.7.2). If an OO is unable to follow these
simple rules, how likely is it that he/she will follow the more
technically complex procedures that might be required for a COTS GPS?

No one wants to cheat with them, it's just the way things going on some
(maybe most) places.

I've seen similar things. Given this, the obvious solution would be to
award badges using the honor system. If this is not acceptable, then
some level of procedural and/or technical security measures must be in
the rules (even if some do not follow them). How much security is enough?

Marc

Marc Ramsey wrote:

You are comparing apples to oranges. GPS measures geometric altitude
with a typical error of, say, +/- 50 feet. Barographs measure
calibrated pressure altitude with a typical error of, say, +/- 50 feet.
GPS altitude can not be corrected to pressure altitude with reasonable
error bounds, unless specific meteorological data is provided for the
time and place of the flight. Pressure altitude can not be corrected to
geometric altitude with reasonable error bounds, unless specific
meteorological data is provided for the time and place of the flight.
Without making these meteorological corrections, geometric and
calibrated pressure altitude can differ by as much as 1000 feet for a
Diamond altitude gain.

The whole altitude task is about the ability to gain certain amount of
energy from air (thermal, wave, something else). For me it's a geometric
issue. If someone is able to get from A to B and the altitude difference
is more than X than it's fine. Not the air pressure at that altitude
qualifies the pilot.
You already agree with it so what do we argue about?

I don't think they are calibrated for all the temperatures.
There is no requirement that barographs be corrected for temperature.

Hmm, those thin metal plates and other small parts could behave quite
differently at +40C than -40C (typical wave temperature at my country).

That barograph should have been marked as potentially faulty. An OO, if
aware of this, should refuse to certify a flight using it until it is
repaired and recalibrated.

Should.

And the most important issue, what I stated
befo neither barographs nor cameras are sealed by OO on most of the
places I visited...


The Sporting Code requires sealing the barograph, but not necessarily
the cameras (SC3 4.6.3, 4.7.2). If an OO is unable to follow these
simple rules, how likely is it that he/she will follow the more
technically complex procedures that might be required for a COTS GPS?

No they won't.

No one wants to cheat with them, it's just the way things going on
some (maybe most) places.


I've seen similar things. Given this, the obvious solution would be to
award badges using the honor system. If this is not acceptable, then
some level of procedural and/or technical security measures must be in
the rules (even if some do not follow them). How much security is enough?

I would accept any trace file and a sign from the OO. Yes, from the
same OO who doesn't seal the barograph. It's the same level of security
as the current barograph+photo process.

/Janos