FLARM.....for good, or evil??

On Oct 28, 9:19*pm, Andy wrote:

Also, to clarify, ADS-B does no path estimation of its own. That
function either would have to be added into an ADS-B unit by the OEM,
similar to the way Flarm does today - unlikely to be done in a glider-
specific way IMO - OR, it would have to be done by a separate external
device, perhaps a navigation computer/software like Oudie, WinPilot,
SN-10. For it to be effective manufacturers would all have to agree to
use the same algorithm, which also seems unlikely, unless they all
adopt the Flarm algorithm. That seems somewhat unlikely too, since I
don't think Flarm would want to start splintering how their algorithms
get used by splitting out the Flarm link technology from the collision
algorithm (which would have to be modified to accommodate the
differences in how path estimations get generated - with unpredictable
results). PLUS the external device OEM's would have to adapt to using
ADS-B inputs - another standards issue.

No matter how hard I try, it seems highly improbable that you will be
able to stitch together a satisfactory collision avoidance system for
gliders using ADS-B technology developed for general aviation. You'd
have to be satisfied with the simple functionality offered by ADS-B -
which would be fine if you generally come into conflict with GA and
airliners more often than other gliders, but there are a bunch of us
for whom the opposite is true. Then the problem becomes some gliders
using Flarm and others using ADS-B, you lose some of the Flarm
benefits of path estimation for the non-Flarm gliders.

9B

9B

On 10/28/2010 10:38 PM, Eric Greenwell wrote:
On 10/28/2010 4:03 PM, Mike Schumann wrote:
On 10/28/2010 3:36 PM, Eric Greenwell wrote:
I can think of three situations where the time involved can be reduced:

1) two gliders approaching head on. At 100 knots each - a 200 knot
closing speed - that's only 18 seconds or so to collision. How many
seconds of warning do you lose while collecting enough points to make a
good estimate of the projected paths - 5 seconds, 10 seconds? I don't
know, but I'd prefer to know sooner than later.

2) Ridge or mountain flying, where the transmissions are blocked by the
terrain. Once they round the corner of the ridge, there may not be
enough time to calculate a projected path.

3) shortened range due to signal blockage by the wings or fuselage.
The proper logic on unexpectedly seeing a new target close by without
have a chance to compute trajectory is to use a worse case scenario.
Granted, having the trajectory as part of the transmission would be
helpful in this instance.
And which way do you turn, when you don't know where the threat is going?


It appears that ADS-B does transmit the location as well as the
instantaneous velocity vector each second, so if you have a graphical
display, you will be able to see the orientation and physical location
of the aircraft immediately. It doesn't currently transmit any turn
rate info. I don't know if it gives you any data on rate of climb /
descent.

A basic FLARM unit, without a graphical display, won't give you any
hints of which direction the target is moving in. It will only give you
a rough idea of where the threat target is, so you have to use your eyes
and judgment to take evasive action.

I suspect that a graphical display is primarily useful to identify the
location and course info for aircraft in your area before you get into
an alarm condition. Once the alarm goes off, you should probably be
looking outside. (Not having flown with these types of units, others
probably have better insights into this).

--
Mike Schumann

On 10/29/2010 12:51 AM, Andy wrote:
On Oct 28, 9:19 pm, wrote:

Also, to clarify, ADS-B does no path estimation of its own. That
function either would have to be added into an ADS-B unit by the OEM,
similar to the way Flarm does today - unlikely to be done in a glider-
specific way IMO - OR, it would have to be done by a separate external
device, perhaps a navigation computer/software like Oudie, WinPilot,
SN-10. For it to be effective manufacturers would all have to agree to
use the same algorithm, which also seems unlikely, unless they all
adopt the Flarm algorithm. That seems somewhat unlikely too, since I
don't think Flarm would want to start splintering how their algorithms
get used by splitting out the Flarm link technology from the collision
algorithm (which would have to be modified to accommodate the
differences in how path estimations get generated - with unpredictable
results). PLUS the external device OEM's would have to adapt to using
ADS-B inputs - another standards issue.

No matter how hard I try, it seems highly improbable that you will be
able to stitch together a satisfactory collision avoidance system for
gliders using ADS-B technology developed for general aviation. You'd
have to be satisfied with the simple functionality offered by ADS-B -
which would be fine if you generally come into conflict with GA and
airliners more often than other gliders, but there are a bunch of us
for whom the opposite is true. Then the problem becomes some gliders
using Flarm and others using ADS-B, you lose some of the Flarm
benefits of path estimation for the non-Flarm gliders.

9B

9B


You are probably correct that no one is going to beat FLARM in an
optimized collision avoidance solution for high density glider
environments. That's obviously their focus and they are good at it.

However, most recreational, non-contest pilots, primarily need a system
that will reliably alert them to other aircraft in their general
vicinity. If I enter a thermal and know that there are 3 other aircraft
in the area, and I only see two, I'm going to abort and go elsewhere. A
contest pilot obviously wants more data.

What is interesting about the Parowan situation is that this was not a
gaggle of gliders. It was two gliders who apparently did not have a
proper appreciation that they were near each other. A simple graphical
display that showed their relative positions, with a very simple
collision avoidance algorithm, or some form of auditory announcement
could have prevented this accident. That's not to say that the FLARM
simulation was not impressive.

--
Mike Schumann

On Oct 28, 11:20*pm, Mike Schumann
wrote:
On 10/29/2010 12:51 AM, Andy wrote:





On Oct 28, 9:19 pm, *wrote:

Also, to clarify, ADS-B does no path estimation of its own. That
function either would have to be added into an ADS-B unit by the OEM,
similar to the way Flarm does today - unlikely to be done in a glider-
specific way IMO - OR, it would have to be done by a separate external
device, perhaps a navigation computer/software like Oudie, WinPilot,
SN-10. For it to be effective manufacturers would all have to agree to
use the same algorithm, which also seems unlikely, unless they all
adopt the Flarm algorithm. That seems somewhat unlikely too, since I
don't think Flarm would want to start splintering how their algorithms
get used by splitting out the Flarm link technology from the collision
algorithm (which would have to be modified to accommodate the
differences in how path estimations get generated - with unpredictable
results). PLUS the external device OEM's would have to adapt to using
ADS-B inputs - another standards issue.

No matter how hard I try, it seems highly improbable that you will be
able to stitch together a satisfactory collision avoidance system for
gliders using ADS-B technology developed for general aviation. You'd
have to be satisfied with the simple functionality offered by ADS-B -
which would be fine if you *generally come into conflict with GA and
airliners more often than other gliders, but there are a bunch of us
for whom the opposite is true. Then the problem becomes some gliders
using Flarm and others using ADS-B, you lose some of the Flarm
benefits of path estimation for the non-Flarm gliders.

9B

9B

You are probably correct that no one is going to beat FLARM in an
optimized collision avoidance solution for high density glider
environments. *That's obviously their focus and they are good at it.

However, most recreational, non-contest pilots, primarily need a system
that will reliably alert them to other aircraft in their general
vicinity. *If I enter a thermal and know that there are 3 other aircraft
in the area, and I only see two, I'm going to abort and go elsewhere. *A
contest pilot obviously wants more data.

What is interesting about the Parowan situation is that this was not a
gaggle of gliders. *It was two gliders who apparently did not have a
proper appreciation that they were near each other. *A simple graphical
display that showed their relative positions, with a very simple
collision avoidance algorithm, or some form of auditory announcement
could have prevented this accident. *That's not to say that the FLARM
simulation was not impressive.

--
Mike Schumann

I played back the igc files from all the gliders flying that day and
can say that your speculation is not really supported by the facts.
Actually there were a number of gliders in that thermal - as it turns
out I passed right by it about a minute after the collision. There was
also a lot of non-thermalling traffic going in both directions at the
time, mostly within a pretty narrow altitude band within a thousand
feet or two of cloud base under a long cloud street.

An issue in these kinds of situations is that you can fixate on a
couple of gliders a bit higher in the thermal and miss the one
entering on a collision course with you at nearly the same time. A
cruder collision system has the potential to false alarm on too many
non-threats and on multiple gliders in the vicinity, making it hard
for the pilot to sort out which one is the real threat. Or it can
falsely identify a non-threat and mask the one that is really the
problem.

At this point I'm not at all sure why you'd pick straight ADS-B
(especially UAT) over something like PowerFlarm. The arguments keep
changing and hard as I try I can't find one that holds water when I
really run through all the issues. I think ADS-B in the long run is a
decent upgrade over PCAS, but PowerFlarm is more cost efficient and
more effective as a collision warning system, plus it has ADS-B in and
PCAS build in.

Also, I'll bet dollars to donuts that PowerFlarm gets FCC approval
well prior to ADS-B getting out from under the STC requirement.

9B

On 10/28/2010 10:21 PM, Darryl Ramm wrote:
On Oct 28, 3:57 pm, Mike
wrote:
On 10/28/2010 5:15 PM, Darryl Ramm wrote:







On Oct 28, 1:54 pm, wrote:
On Oct 28, 1:40 pm, "Wayne wrote:

"Darryl wrote in ...
On Oct 28, 8:47 am, wrote:

Just to give a flavor ADS-B data-out systems as mandated for 2020 in
the USA for power aircraft (basically where a transponder is required
today) will put out the following data

Aircraft ICAO ID (can be made anonymous for a UAT on VFR flight)
Aircraft callsign/flight number (not required for VFR flight)
Time of applicability
GPS Lattitude
GPS Longitude
GPS altitude
Airborne/on-surface status
Northbound ground velocity component while airborne (from GPS)
Eastbound ground velocity component while airborne (from GPS)
Heading while on the surface
Ground speed while on the surface
Pressure altitude
Vertical rate (may be pressure or GPS based)
GPS uncertainty/integrity (which needs information form a fancy TSO-
C145 class WAAS GPS)
Ident (equivalent to transponder ident/SPI)
Distress/Emergency status
ADS-B data-in/display capability
TCAS equipage/status

This is a simplified list and there is various other status/validity
data as well. There is also the concept in ADS-B messages of an
estimated position, and even estimated velocity. But AFAIK this is not
intended for fancy manoeuvrings predictions - it is more intended to
allow different parts of the ADS-B infrastructure to project position
or velocity updated to a single time of applicability. There is space
for future expansion and as an example there is long-term work
underway to look at an ADS-B based replacement for TCAS that could
well utilize extra data transmission than that above, but think well
post 2020 for this to actually happen. My brain hurts enough thinking
about ADS-B as is.

---

BTW my suspicion is given that the FAA currently requires a STC for
any installation for ADS-B data out that it is currently not possible
to install any ADS-B data-out system in the USA in any certified
aircraft (including gliders) that only meets a subset of the 2020
mandate requirements (ie. does not include all the stuff above). Which
I expect the FAA would also require fully TSO-C154c/DO-282B (UAT) TSO-
C166b/DO-260B (1090ES) and with the corresponding TSO-C145 level GPS.
Experimental aircraft are another question since an STC cannot apply
to them. This STC restriction hopefully is short-term as its is going
to have a chilling effect on ADS-B data-out adoption in general
aviation and gliders. Besides some more complex issues you can start
to see even simple installation concerns that are probably causing
this current STC requirement, such as squat switch/or other on-ground
detection, needs to have a single squawk code and ident button across
any installed transponder(s) and ADS-B data-out devices, ability to
transmit a distress/emergency code, ability to turn off the ADS-B
transmissions if requested, etc.

Darryl

The following is not directed at any individual, it is simply an observation.

Even the old Garmin 12XL provides a lot more information in it's NMEA sentences the most of us realize. It is data output sentences are fully compliant with NMEA 0183 ver 2.0. The following link give an example of the data provided by "GPS engines" to software developer thus minimizing the amount of calculation required in display devices.http://www8.garmin.com/support/pdf/NMEA_0183.pdf

As I watch these PowerFLARM discussion it is apparent that many assume that things provided by the GPS must be created by the FLARM software.

Let us accept the fact that the PowerFLARM is just an upgrade of previous units that have been proven effective in increasing glider flight safety.

Respectfully,
Wayne

There have been several comment regarding the need for an STC to
install an ADS-B system in a certified aircraft.

This is not unlike the original situation with the installation of IFR
certified GPS systems, in the early 1990s. I was involved in several
installations and most of the concerns were about the placement of
antenna and the effect of spurious signals on navigation.

Today if you get an IFR GPS installed in an aircraft the manufacturer
has a detailed description of antenna placement, cable routing and
possible interaction. This data was collected during the earlier STC
period and as experience with more installations was gained, the FAA
changed the requirements from an STC to a 337, if installed in
compliance with the manufacturer's instructions.

I expect that the STC requirements for the ADS-B will follow the same
path over time.

Mike

Absolutely right (and antenna issues are one of the concerns with this
STC requirement as well). Its a matter of when the STC process
migrates to a 337/Field approval. Given the complexity of ADS-B I
wonder what the time frame will really be. And the FCC has stated that
clearly but the STC requirement still seems to have come as a bit of a
surprise to some developers--and maybe regulators where there are
questions if the cost of this was included in disclosures. I see no
way for now but for this to freeze a lot of adoption--but I suspect
from the FAA viewpoint it is needed. I do worry that smaller
manufacturers won't be able to develop many STCs and I am doubtful
you'll see folks willing to develop STCs for gliders. My purpose of
promoting the STC issue is just nobody seemed to be aware of it in
the glider community yet there are (a few) owners starting to look at
install of ADS-B data-out. Some of those owners have experimental
gliders and are in a better position. Those with certified gliders
need to have a discussion with vendors about STCs. In a practical
sense as well most vendors are busy finishing off their "-B" rev data-
out products (e.g. Garmin, Trig and others) and getting TSO approval
on those. And I see that as a gate to STC approval, but clearly they
could be overlapping TSO approval and STC development. And larger
companies beside having lots of STC approval experience may also be
able to leverage past ADS-B STC developed for trails, such as the
GOMEX ADS-B trials.

Darryl

I find it difficult to understand the "complexity" involved in ADS-B.
This is basically the same technology as FLARM (UAT) or Mode S
transponders (1090ES). The main difference between FLARM and UAT is the
frequency and power level of the transmitter. (Yes I know that UAT
doesn't include any of the collision detection logic of FLARM).

At some point, the FAA will figure this out or the whole ADS-B exercise
will come to a dead end.

--
Mike Schumann

ADS-B and its implementation and role in NextGen and all the different
players looking at this beast from all different angles and trying to
solve all sorts of different problems makes this is one of the most
complex undertakings ever in aviation.... and that includes everything
from the details of the data transmitted on up (e.g. the GPS chip in a
Flarm likely costs a few tens of dollars at most, a GPS box or module
for an ADS-B data-out TSO'ed product currently costs thousands of
dollars). All that extra stuff and bureaucracy that make it cost that
much really has no practical benefit for glider-glider collision
avoidance but has benefits to others.

Lets see, ADS-B data-out, ADS-B data-in, 1090ES, UAT, ADS-R, TIS-B,
FIS-B, surface surveillance, terminal surveillance, en-route
surveillance, essential services, critical services, TSO-C166b/
DO-260B, TSO-C154c/DO-282B, TSO-C145a/TSO-C146a WAAS GPS, SIL, NIC,
STCs, ... if this does not make your head ache you may not be thinking
about it hard enough. Most people just don't need to worry since this
is all years away from being interesting for them. Years away when FAA
ground services, ADS-B products, product cost, fleet adoption and
market awareness all start to line up.

And this applies to the ADS-B receiver part PowerFLARM as well -
especially its dependence on having ADS-B out for ADS-R and TIS-B to
work. There is a lot more the FAA and its providers have to do and
there is a lot more we all have to do to understand all this
technology and how best to use it moving forward - given that by 2020
a significant part of the entire USA aircraft fleet will be ADS-B data-
out equipped. But again I'm not trying to hawk ADS-B as being at all
ready for our market now, but I've very happy to see products like
PowerFLARM providing a path to include that in future.

Darryl

You are confusing ADS-B and everything else under the "Nextgen" umbrella.

ADS-B is fundamentally a very simple concept. You have a GPS in your
airplane, and once a second you transmit your position and velocity
vector data. On the receive side, you listen and receive everyone
else's position. Additional data may also be available if you are
interested (weather, Notams, etc.).

ADS-B is basically the same as FLARM, except that FLARM also includes
collision avoidance features that need to be implemented externally to
the ADS-B transceiver, if the user desires this capability. The only
fundamental differences between ADS-B and FLARM is the frequency used to
communicate between aircraft, the power level of the transmitters and
the protocol used. There is no technical reason that the US version of
FLARM data link could not have been implemented to be ADS-B compatible.
Granted, the FLARM guys would have had to invest in extra engineering
to change their protocols, and then would have had to deal with the FAA
BS involved with ADS-B, so it is totally understandable, from a business
perspective, why they did not go down this path.

The problem with ADS-B is all the regulatory crap and "integrity" BS
that the FAA dumped on the avionics manufacturers that has made it
impossible to develop hardware at an affordable price point. The
"complexity" is not in the fundamental technology, but in working thru
the FAA process to get this equipment approved.

It is a huge failure of the FAA, AOPA, the SSA, and the rest of the US
aviation community that this program has turned into such a fiasco. If
the fundamental focus had been on affordability, there is no reason that
we couldn't now have commercial ADS-B equipment at the same price points
as FLARM units.

--
Mike Schumann

On 10/29/2010 4:11 AM, Andy wrote:
On Oct 28, 11:20 pm, Mike
wrote:
On 10/29/2010 12:51 AM, Andy wrote:





On Oct 28, 9:19 pm, wrote:

Also, to clarify, ADS-B does no path estimation of its own. That
function either would have to be added into an ADS-B unit by the OEM,
similar to the way Flarm does today - unlikely to be done in a glider-
specific way IMO - OR, it would have to be done by a separate external
device, perhaps a navigation computer/software like Oudie, WinPilot,
SN-10. For it to be effective manufacturers would all have to agree to
use the same algorithm, which also seems unlikely, unless they all
adopt the Flarm algorithm. That seems somewhat unlikely too, since I
don't think Flarm would want to start splintering how their algorithms
get used by splitting out the Flarm link technology from the collision
algorithm (which would have to be modified to accommodate the
differences in how path estimations get generated - with unpredictable
results). PLUS the external device OEM's would have to adapt to using
ADS-B inputs - another standards issue.

No matter how hard I try, it seems highly improbable that you will be
able to stitch together a satisfactory collision avoidance system for
gliders using ADS-B technology developed for general aviation. You'd
have to be satisfied with the simple functionality offered by ADS-B -
which would be fine if you generally come into conflict with GA and
airliners more often than other gliders, but there are a bunch of us
for whom the opposite is true. Then the problem becomes some gliders
using Flarm and others using ADS-B, you lose some of the Flarm
benefits of path estimation for the non-Flarm gliders.

9B

9B

You are probably correct that no one is going to beat FLARM in an
optimized collision avoidance solution for high density glider
environments. That's obviously their focus and they are good at it.

However, most recreational, non-contest pilots, primarily need a system
that will reliably alert them to other aircraft in their general
vicinity. If I enter a thermal and know that there are 3 other aircraft
in the area, and I only see two, I'm going to abort and go elsewhere. A
contest pilot obviously wants more data.

What is interesting about the Parowan situation is that this was not a
gaggle of gliders. It was two gliders who apparently did not have a
proper appreciation that they were near each other. A simple graphical
display that showed their relative positions, with a very simple
collision avoidance algorithm, or some form of auditory announcement
could have prevented this accident. That's not to say that the FLARM
simulation was not impressive.

--
Mike Schumann

I played back the igc files from all the gliders flying that day and
can say that your speculation is not really supported by the facts.
Actually there were a number of gliders in that thermal - as it turns
out I passed right by it about a minute after the collision. There was
also a lot of non-thermalling traffic going in both directions at the
time, mostly within a pretty narrow altitude band within a thousand
feet or two of cloud base under a long cloud street.

An issue in these kinds of situations is that you can fixate on a
couple of gliders a bit higher in the thermal and miss the one
entering on a collision course with you at nearly the same time. A
cruder collision system has the potential to false alarm on too many
non-threats and on multiple gliders in the vicinity, making it hard
for the pilot to sort out which one is the real threat. Or it can
falsely identify a non-threat and mask the one that is really the
problem.

At this point I'm not at all sure why you'd pick straight ADS-B
(especially UAT) over something like PowerFlarm. The arguments keep
changing and hard as I try I can't find one that holds water when I
really run through all the issues. I think ADS-B in the long run is a
decent upgrade over PCAS, but PowerFlarm is more cost efficient and
more effective as a collision warning system, plus it has ADS-B in and
PCAS build in.

Also, I'll bet dollars to donuts that PowerFlarm gets FCC approval
well prior to ADS-B getting out from under the STC requirement.

9B

Contrary to what everyone seems to think, I am not fundamentally opposed
to PowerFLARM. I understand the sophistication of its collision
avoidance logic, and it is very impressive and useful. I totally get
the necessity for reducing false alarms, so that the alarms that are
issued are meaningful.

My disappointment with PowerFLARM is the lack of a clear plan to take
advantage of the extensive ADS-B ground station infrastructure that will
cover much of the US in the next year or so, to provide the same level
of collision avoidance to transponder equipped GA and commercial traffic
that is available between PowerFLARM equipped gliders.

Granted, the PCAS capability built into PowerFLARM gives you some level
of protection, but you have no information on relative direction of the
threat, and a very crude estimate of its range. I find it very
difficult to understand how PowerFLARM will be able to suppress PCAS
initiated alarms from Mode C transponder equipped gliders in a gaggle,
while simultaneously still generating PCAS alarms from other GA aircraft
that also in the area.

The built-in 1090ES ADS-B In capability is great, but that doesn't
provide any ground station originated data unless you are transmitting
ADS-B out. The new Trig Mode S transponders provide this capability,
but require a GPS source. Is PowerFLARM going to provide this, or what
is the plan for glider pilots to end up with a complete ADS-B compatible
solution?

--
Mike Schumann

On Oct 29, 11:32*am, Mike Schumann
wrote:
On 10/29/2010 4:11 AM, Andy wrote:



On Oct 28, 11:20 pm, Mike
wrote:
On 10/29/2010 12:51 AM, Andy wrote:

On Oct 28, 9:19 pm, * *wrote:

Also, to clarify, ADS-B does no path estimation of its own. That
function either would have to be added into an ADS-B unit by the OEM,
similar to the way Flarm does today - unlikely to be done in a glider-
specific way IMO - OR, it would have to be done by a separate external
device, perhaps a navigation computer/software like Oudie, WinPilot,
SN-10. For it to be effective manufacturers would all have to agree to
use the same algorithm, which also seems unlikely, unless they all
adopt the Flarm algorithm. That seems somewhat unlikely too, since I
don't think Flarm would want to start splintering how their algorithms
get used by splitting out the Flarm link technology from the collision
algorithm (which would have to be modified to accommodate the
differences in how path estimations get generated - with unpredictable
results). PLUS the external device OEM's would have to adapt to using
ADS-B inputs - another standards issue.

No matter how hard I try, it seems highly improbable that you will be
able to stitch together a satisfactory collision avoidance system for
gliders using ADS-B technology developed for general aviation. You'd
have to be satisfied with the simple functionality offered by ADS-B -
which would be fine if you *generally come into conflict with GA and
airliners more often than other gliders, but there are a bunch of us
for whom the opposite is true. Then the problem becomes some gliders
using Flarm and others using ADS-B, you lose some of the Flarm
benefits of path estimation for the non-Flarm gliders.

9B

9B

You are probably correct that no one is going to beat FLARM in an
optimized collision avoidance solution for high density glider
environments. *That's obviously their focus and they are good at it.

However, most recreational, non-contest pilots, primarily need a system
that will reliably alert them to other aircraft in their general
vicinity. *If I enter a thermal and know that there are 3 other aircraft
in the area, and I only see two, I'm going to abort and go elsewhere. *A
contest pilot obviously wants more data.

What is interesting about the Parowan situation is that this was not a
gaggle of gliders. *It was two gliders who apparently did not have a
proper appreciation that they were near each other. *A simple graphical
display that showed their relative positions, with a very simple
collision avoidance algorithm, or some form of auditory announcement
could have prevented this accident. *That's not to say that the FLARM
simulation was not impressive.

--
Mike Schumann

I played back the igc files from all the gliders flying that day and
can say that your speculation is not really supported by the facts.
Actually there were a number of gliders in that thermal - as it turns
out I passed right by it about a minute after the collision. There was
also a lot of non-thermalling traffic going in both directions at the
time, mostly within a pretty narrow altitude band within a thousand
feet or two of cloud base under a long cloud street.

An issue in these kinds of situations is that you can fixate on a
couple of gliders a bit higher in the thermal and miss the one
entering on a collision course with you at nearly the same time. *A
cruder collision system has the potential to false alarm on too many
non-threats and on multiple gliders in the vicinity, making it hard
for the pilot to sort out which one is the real threat. Or it can
falsely identify a non-threat and mask the one that is really the
problem.

At this point I'm not at all sure why you'd pick straight ADS-B
(especially UAT) over something like PowerFlarm. The arguments keep
changing and hard as I try I can't find one that holds water when I
really run through all the issues. I think ADS-B in the long run is a
decent upgrade over PCAS, but PowerFlarm is more cost efficient and
more effective as a collision warning system, plus it has ADS-B in and
PCAS build in.

Also, I'll bet dollars to donuts that PowerFlarm gets FCC approval
well prior to ADS-B getting out from under the STC requirement.

9B

Contrary to what everyone seems to think, I am not fundamentally opposed
to PowerFLARM. *I understand the sophistication of its collision
avoidance logic, and it is very impressive and useful. *I totally get
the necessity for reducing false alarms, so that the alarms that are
issued are meaningful.

My disappointment with PowerFLARM is the lack of a clear plan to take
advantage of the extensive ADS-B ground station infrastructure that will
cover much of the US in the next year or so, to provide the same level
of collision avoidance to transponder equipped GA and commercial traffic
that is available between PowerFLARM equipped gliders.

Granted, the PCAS capability built into PowerFLARM gives you some level
of protection, but you have no information on relative direction of the
threat, and a very crude estimate of its range. *I find it very
difficult to understand how PowerFLARM will be able to suppress PCAS
initiated alarms from Mode C transponder equipped gliders in a gaggle,
while simultaneously still generating PCAS alarms from other GA aircraft
that also in the area.

The built-in 1090ES ADS-B In capability is great, but that doesn't
provide any ground station originated data unless you are transmitting
ADS-B out. *The new Trig Mode S transponders provide this capability,
but require a GPS source. *Is PowerFLARM going to provide this, or what
is the plan for glider pilots to end up with a complete ADS-B compatible
solution?

--
Mike Schumann

Somewhere earlier in this thread someone noted that they were planning
on doing that soon. I plan on doing it myself, except that the $4K
pricetag
means it will take a while to save up for it. Also, the TSO fiasco
throws
a big question mark over the ADS-B out part of the equation. My plane
(ASW-19) is type certified in the US, so the TSO requirement applies
to me.

-- Matt

On 10/29/2010 11:16 AM, Mike Schumann wrote:
If the fundamental focus had been on affordability, there is no reason
that we couldn't now have commercial ADS-B equipment at the same price
points as FLARM units.

NavWorx announced on Wednesday Oct. 27 that they are currently shipping
the ADS600B transceivers.
They offer their informal solution to the FAA's STC and/or TSO mandates
can be installed on both experimental and certified aircraft when it meets “portable installation guidelines.”

Mike, I think you do not understand the fundamental difference between
ADS-B and FLARM.

ADS-B is designed for aircraft that do not want to fly close to each
other, and want/need long range situational awareness. Thats probably
where the whole ground station setup comes from - with all it's
disadvantages (coverage, latency, accuracy, etc.) It's a great system
for IFR traffic, and for GA flyers out sightseeing, but it sucks for
gliders in a gaggle or running a ridge.

FLARM, on the other hand, is specifically designed for aircraft
(gliders, helicopters) that often want to fly close to each other,
safely. In a gaggle, running a ridge, heading for the really nice Cu
near the glider field, on the Whites - gliders inherently will
congregate to find the best lift. That is the threat environment
FLARM is designed to cope with. And it's a proven item.

In a perfect world, there would be a SuperFLARM that would add some
sort of ADS-B in/out capability, so the benefits of both would be
present. But until then, FLARM addresses the immediate concern of
many, if not most glider pilots the best. A PowerFLARM, combined with
a mode s transponder, gives a glider most of the useful threat warning
capability of a full up ADS-B setup, and all the advantages of FLARM -
if FLARM is widely adopted by the US soaring community.

But if no-one gets ADS-b in their gliders (show of hands out there?),
then it's of no use in preventing the biggest historical threat -
glider on glider collisions.

I'm planning on getting a PowerFLARM next season to replace my PCAS.
I hope you will to, while waiting for your ADS-B to be installed.


Kirk
66

On 10/29/2010 11:37 AM, kirk.stant wrote:
Mike, I think you do not understand the fundamental difference between
ADS-B and FLARM.

ADS-B is designed for aircraft that do not want to fly close to each
other, and want/need long range situational awareness. Thats probably
where the whole ground station setup comes from - with all it's
disadvantages (coverage, latency, accuracy, etc.) It's a great system
for IFR traffic, and for GA flyers out sightseeing, but it sucks for
gliders in a gaggle or running a ridge.

FLARM, on the other hand, is specifically designed for aircraft
(gliders, helicopters) that often want to fly close to each other,
safely. In a gaggle, running a ridge, heading for the really nice Cu
near the glider field, on the Whites - gliders inherently will
congregate to find the best lift. That is the threat environment
FLARM is designed to cope with. And it's a proven item.

In a perfect world, there would be a SuperFLARM that would add some
sort of ADS-B in/out capability, so the benefits of both would be
present. But until then, FLARM addresses the immediate concern of
many, if not most glider pilots the best. A PowerFLARM, combined with
a mode s transponder, gives a glider most of the useful threat warning
capability of a full up ADS-B setup, and all the advantages of FLARM -
if FLARM is widely adopted by the US soaring community.

But if no-one gets ADS-b in their gliders (show of hands out there?),
then it's of no use in preventing the biggest historical threat -
glider on glider collisions.

I'm planning on getting a PowerFLARM next season to replace my PCAS.
I hope you will to, while waiting for your ADS-B to be installed.


Kirk
66

I think that you have a fundamental misunderstanding of ADS-B. ADS-B is
a general purpose system that is designed to permit aircraft to announce
their position and velocity vectors to anyone who is interested. For
all practical purposes, it has the same accuracy, latency, etc. of FLARM
based systems. It doesn't make any difference if aircraft are flying in
close proximity or not.

FLARM does the same thing and then adds another layer of collision
detection logic on top of that, which is specifically optimized for the
glider world. There is no reason that the same logic could not also be
added on-top of an ADS-B based position sensing technology. In fact,
PowerFLARM claims to be doing this using their 1090ES IN capability, if
the user has ADS-B Out installed.

The ground station ADS-B infrastructure is being deployed for 4 reasons:

1. To provide translation of ADS-B transmissions between UAT and 1090ES
(an unfortunate necessity due to the FAA's decision to go with 2 ADS-B
formats in the US)

2. To transmit TIS-B data. This lets ADS-B IN equipped aircraft see
the position and altitude of Mode C and S Transponder equipped aircraft
which are not yet outfitted with ADS-B transmitters.

3. To transmit additional weather and NOTAM information.

4. To detect ADS-B equipped aircraft so that they can be displayed on
ATC radar displays.


--
Mike Schumann