"Do It Yourself" airborne proximity warning device

Well, define "accurate", and "could put in a glider".

I've never seen one, but the rather boxy Zaon "XRX" was supposed to give azimuth information. I believe it was crude ( quadrant or octant ), and I have no information about how well it worked other than reviews. I have a Zaon "MRX", which is a small altitude-only reporting receiver, and find it useful. Too bad Zaon closed operations recently.

Review: http://www.flyingmag.com/avionics-ge...oidance-system

On Tuesday, December 10, 2013 2:34:45 PM UTC-6, wrote:
...


I am not aware of any system you could even adapt to put in a glider that would allow you to get accurate azimuth information off of transponder returns - even in theory.



9B

On Tuesday, December 10, 2013 1:41:26 PM UTC-8, Sarah wrote:

Well, define "accurate", and "could put in a glider".

Fair enough.

If you were able to put TCAS in a glider that would do it, but trying to get azimuth information off of passive monitoring of radar returns (like PCAS does) has to be a hit-or-miss proposition (pun intended) since you don't have the ability to actively interrogate other transponder-equipped aircraft to string together enough bits of information to get good direction. You are dependent on ground radar or TCAS-equipped aircraft to do the interrogating for you which is no always reliable. Some sort of directional antenna added to a PCAS might help in the way you describe (showing quadrants), but I have to believe it's not the sort of thing you could really count on and would totally suck for glider-glider scenarios.

I'd also add that the research shows that no matter how diligent the scan, see-and-avoid detects not more than half the targets that are collision threats. Non-threats are much easier to pick up because of the angular movement of non-collision targets. So, the fact that you see other aircraft when you are flying to some extent generates a false sense of security - your are much less likely to see the one that's going to actually hit you. There are scenarios in the research where successful detection in time to act is on the order of 10-20%. That gave me some pause.

9B

On Tuesday, December 10, 2013 1:41:26 PM UTC-8, Sarah wrote:
Well, define "accurate", and "could put in a glider".



I've never seen one, but the rather boxy Zaon "XRX" was supposed to give azimuth information. I believe it was crude ( quadrant or octant ), and I have no information about how well it worked other than reviews. I have a Zaon "MRX", which is a small altitude-only reporting receiver, and find it useful. Too bad Zaon closed operations recently.



Review: http://www.flyingmag.com/avionics-ge...oidance-system


And there was only one serious trial of an Zaon XRX in a glider that I am aware of and it did not do well and was removed. The upper and lower phased array antennas that TCAS II uses to get it their rough quadrant direction information is well beyond what is in a XRX type system or what you could/would want to install in a glider at all. TCAS III was supposed to provide accurate threat direction information for airliners etc., the complexity of doing that was one reason TCAS III was an abject failure and TCAS II stayed on being used.

Investing money/effort in positional transponder type systems seems a wasted effort given that FLARM exists and is already widely installed in glider fleets in many regions and that over time ADS-B will provide high resolution position report of lots of Airline, Fast jet, Military and GA traffic (eventually on-par with transponder carriage, possibly as early as a few years after 2020). But yes, even then we'll have issues with ADS-B including the dual-link silliness in the USA, problems equipping for ADS-B data-out carriage, etc.

Sorry, but you got incomplete information. I checked your link and the
Raytheon radar is just a part of one of the systems produced by Sensis Corp.
(now Saab-Sensis).

The rotating antenna on top of the control tower is either an FAA ASDE-3
radar or an ASDE-X (Raytheon) radar. ASDE-X and ASDE-3X (using the FAA
radar) fuse data from radar and transponders, both airborne and on the
ground, into a position/altitude. The radar is an adjunct to TDOA and FDOA
(time and frequency difference of arrival of signals) geopositioning and
aids in position accuracy, but is not required to generate a position.

My statements come from prior work as Test Director during acceptance of the
ASDE-3X system at Louisville, KY (SDF). There are 30+ of these systems
worldwide at major and second tier airports.

The company that produced ASDE-X and -3X also setup systems in Colorado and
Alaska which allowed ATC to derive aircraft positions in remote areas which
have no radar coverage.

There were additions in the concept stage when I left the company that
included in-cockpit displays of traffic detected by the system but that was
over 5 years ago and I have no idea of whether they ever came to fruition.
But, like anything aviation related, it would probably cost both arms and
legs.

wrote in message
...
On Tuesday, December 10, 2013 10:19:07 AM UTC-8, Dan Marotta wrote:

Maybe someone should develop a device like the MRX PCAS which detects
transponders and includes azimuth in addition to range and elevation.
Most
of the algorithms have already been developed. There are well established
methods for very accurately locating a transponder. Look up ASDE-X, for
example (LAT/LON/ALT derived from transponder replies). Alas, I suspect
development cost would far outweigh expected return on investment.

I looked it up - ADSE-X is an active radar system that uses either a
rotating or phased array antenna (apparently normally mounted on top of the
control tower). It's not the sort of thing you'd find you could fit in a
glider - even if it were legal. Here's a long to a schematic of the
Raytheon version:

http://avstop.com/stories/asde.html

I am not aware of any system you could even adapt to put in a glider that
would allow you to get accurate azimuth information off of transponder
returns - even in theory.

9B

On Wednesday, December 11, 2013 9:07:33 AM UTC-8, Dan Marotta wrote:

But, like anything aviation related, it would probably cost both arms and
legs.

Maybe someone should develop a device like the MRX PCAS which detects
transponders and includes azimuth in addition to range and elevation.

Thanks for the info on the ASDE-X system Dan - I think you are right that it's unlikely to make a cost-effective anti-collision system in the end.

I think Sarah's link to the Zaon XRX represents an attempt at what you are talking about that only costs one arm. It carried a retail price of $1395.. Even if it were in production today I'd still rather carry a PowerFlarm for that kind of money because you'd get actual 1090ES GPS fixes plus PCAS plus glider Flarm traffic for about the same price. I think in general the idea of trying to interpret radar returns - even with a lot of calculus of variations math - is by now antiquated and far inferior to more modern GPS-based solutions. The review on the XRX seemed to confirm this - it only sometimes worked.

I looked up ABQ in the FAA's Air Traffic Activity System. On an average summer weekend soaring day it handles about 100 total airport operations during the active soaring day, which places it at #116 among airports in the US - a reasonably busy airport. Even so, I'd bet dollars to donuts that if you took all the IGC traces and all the radar traces and compared them you'd find on a typical glider flight that more than 9 out of 10 of the closest approaches to another aircraft would be another glider or towplane, not a commercial jet.

That's not to say I'm advising against a transponder - I often fly near Reno (#197 in summer weekend airport operations) and I carry one. Yes there are differences across airports in terms of how the jet approaches mix with glider flights. However - if we take it back to actual statistics, I expect ABQ is not so atypical a traffic situation to overcome the more than 10x difference in the statistics on average - that is, you are more than 10x as likely to run into another glider or local traffic at your home airport than a jet. The big jets are certainly more obvious and scarier and would make a bigger headline if you actually hit one, but the outcome for you is the same whether you smash into one of those or your soaring buddy. For that reason I consider carrying a transponder more of a public service than my primary device for personal safety - my PowerFlarm, InReach, parachute and extra drinking water all rank ahead of my transponder in terms of personal safety - more or less in that order.

9B

On Tuesday, December 10, 2013 12:19:07 PM UTC-6, Dan Marotta wrote:
Maybe someone should develop a device like the MRX PCAS which detects

transponders and includes azimuth in addition to range and elevation.


Hmm, that's exactly what PowerFlarm does with ADS-B/mode S targets. Which are becoming more and more common, and includes pretty much all fast movers and advanced GA planes. Plus PF gives you the same data as an MRX (I have both - now use the MRX for towplanes and club gliders). And you get really good (as in Link-16 good) glider to glider cooperative data.

So lets see - I believe you have a transponder in your glider (about $2k) and a MRX $500 and I assume a parachute (about $2k). So you see the risk is airliners (transponder for TCAS), lightplanes (MRX), and something that will make you need to make a nylon letdown. But by your own statistics, the PowerFLARM is more useful than the parachute, replaces the MRX, and lets you see airliners BEFORE they run you down or have to maneuver around you ("Hey, FSDO, get that clown in the glider out of our approach path!"

To me it's a no-brainer. Where I fly, the transponder provides the least protection, so I haven't yet tried to squeeze one into my '6. But having experienced the SA that the PF provides in a glider-rich environment, and the SA it gives on nearby power traffic, I don't like flying without it anymore!

Of course, we all have to make decisions based on our perceived risk - but i find your dismissal of PF a bit perplexing, especially since you use the much more limited MRX and count on your xponder to keep from getting run over by a fast mover!

Oh, yeah, see and avoid. Right. How about BIG SKY theory - that's really what keeps the midairs down to a tolerable level in the US. In France they finally realized that they no longer have the luxury of a big sky, and now FLARM is mandated for all gliders.

Not so dumb, those cheese-eating surrender monkeys!

Kirk

OT, I just spent 9 months working in France. Sure was nice being in a civilized, modern country. Coming back to St Louis was like being sent off to a third world country! But hey, at least we have more cable channels!

Thanks for the morning chuckle, Kirk. Civilization is in the eye of the
beholder, though I must agree with you about St. Louis...

I fly in a glider poor sky so Flarm is of little use to me. That's the
simple truth. Now, when a $1,500, panel mounted ADS-B system is approved
for GA aircraft, I'll drop my MRX and install one of those. I promise!


"kirk.stant" wrote in message
...
On Tuesday, December 10, 2013 12:19:07 PM UTC-6, Dan Marotta wrote:
Maybe someone should develop a device like the MRX PCAS which detects

transponders and includes azimuth in addition to range and elevation.


Hmm, that's exactly what PowerFlarm does with ADS-B/mode S targets. Which
are becoming more and more common, and includes pretty much all fast movers
and advanced GA planes. Plus PF gives you the same data as an MRX (I have
both - now use the MRX for towplanes and club gliders). And you get really
good (as in Link-16 good) glider to glider cooperative data.

So lets see - I believe you have a transponder in your glider (about $2k)
and a MRX $500 and I assume a parachute (about $2k). So you see the risk is
airliners (transponder for TCAS), lightplanes (MRX), and something that will
make you need to make a nylon letdown. But by your own statistics, the
PowerFLARM is more useful than the parachute, replaces the MRX, and lets you
see airliners BEFORE they run you down or have to maneuver around you ("Hey,
FSDO, get that clown in the glider out of our approach path!"

To me it's a no-brainer. Where I fly, the transponder provides the least
protection, so I haven't yet tried to squeeze one into my '6. But having
experienced the SA that the PF provides in a glider-rich environment, and
the SA it gives on nearby power traffic, I don't like flying without it
anymore!

Of course, we all have to make decisions based on our perceived risk - but i
find your dismissal of PF a bit perplexing, especially since you use the
much more limited MRX and count on your xponder to keep from getting run
over by a fast mover!

Oh, yeah, see and avoid. Right. How about BIG SKY theory - that's really
what keeps the midairs down to a tolerable level in the US. In France they
finally realized that they no longer have the luxury of a big sky, and now
FLARM is mandated for all gliders.

Not so dumb, those cheese-eating surrender monkeys!

Kirk

OT, I just spent 9 months working in France. Sure was nice being in a
civilized, modern country. Coming back to St Louis was like being sent off
to a third world country! But hey, at least we have more cable channels!

Interesting read, it has glider pilot creation written all over it. My first impression was that it looks wirey (just invented a new word). I then spent 15 minutes on the net to price the components (identical in most cases but a few exceptions). I got a total of just under $100 on Amazon and Ebay 'buy it now'. I did not include for battery or PDA.
You have 2 types of pilots, the competition guy and the week-end warrior. In most cases, the comp guy is going to have a high end ship and therefore the $1700 powerflarm is an acceptable cost, the week end warriors on the other hand can have a system for approx. 200 bucks (estimating background, take the cost and double it).
I sounds like Linar has started something and based on the above still has some bugs to sort out but Hey! Is is a start.
I will definitely keeps tabs on this thread.

mas

Thank you for your responses!

I've exhaused my spare time slot today for answering on e-mails.
So I'll leave my comments on this thread later on.
But for now I would like to remind you that:

- it is up to a human being to build an item himself(herself) or buy a product from reseller;
- it is responsibility of Pilot-in-Command and nobody else to carry onboard anything he(she) wants that is within w&b limitations and allowed by law;
- it is responsibility of Pilot-in-Command and nobody else to operate while in flight an electronic device or keep it switched off.

Compatibility with other devices of similar purpose can be acheived with at least three different ways:
1) alternative device can be pluged-in into spare USB hub slot through USB-RS232 adapter. A software converter of NMEA messages will translate PFLAU/PFLAA traffic alert messages into the input format of the device developed by topic-starter. But this is "read-only", one-way method;
2) second way is reverese-engineering of radio protocol. That was already done before (in 2008) and where published in this newsgroup followed by reaction of manufacturer.
See this thread: https://groups.google.com/forum/#!ms...s/KOoAiKhERhUJ
3) to purchase a license or invite a current licensee to contribute compatibility into this open project;

Any of above can be done then contributed by volunteer who wants to add the compatibility into this project.

Our club's fleet is about 40+ sailplanes and 5 tow planes. Only three of these aircrafts currently carry onboard a Flarm device. Owners are typically keep them switched off because it makes little sense to drawn battery power when majority of traffic is not equipped with Flarm.

For me, personally, I have no plans to spend my own time to develop compatibility with Flarm. ADS-B is comming soon. So any other devices will leave from market within next few years unless they will switch onto ADS-B standard.
Thus operation on ADS-B is the way where the project should go.

2-way ADS-B USB plug-in for this device is a module that worth to be developed within next couple years.