### UAV swarm, anticollision - faa - detect-and-avoid

Since UAV activity is largely constrained by the see-and-avoid issues;I though it would be appropriate to propose a solution which is compatible for every form of flight from gnat-weight to jumbojets. I've worked this out is a simulator - but here is the jist:This requires only a single frequency and very short blips.1. Every plane determines it's location and vector by GPS.2. Then it transmits this information using one short blip every second or so.a. The blip timing is based on current GPS location, so that the blips cannot interfere, and their location in Timespace tells us where they are coming from. Since GPS provides a very accurate, shared time base. So let t in microseconds = latitude\1 + longitude\1 * 100 + Alt in Km *1000 .b. Odd seconds communicate vector (ie destination), Even seconds communicate Location.3. There is a third variable required - which I call "Density". Each plane calculates the perceived Density of their airspace and sends that as well. Your density is your passenger count divided by the distance between you and other planes multiplied by their perceived density.4. For manned aircraft nothing further is required - this beacon signal will ward off all unmanned vehicles.5. For Autopilot or UAV, it is possible to chart a new safe vector by trying random vector changes and calculating their future density based on the vectors and densities of nearby airplanes. The vector which optimizes progress toward destination with lowest density is the vector chosen.Advantages:simple calculation requirements (ie Arduino), cheap transmitter/receiver requirements, and low power requirements. cheap unit cost, and no ground control.Such a system could be demonstrated by coordinating a swarm of Ardu-Planes.Ben

#### Replies

• Hi Ben

I have read your suggestions for a anti collision system and it sounds like the existing FLARM system...

FLARM is a voluntarily carried, GPS based warning system and very popular in Europe, since it also includes ground based obstecals for example. It is, however, not officially certified as an anti-collision solution, because this would multiply the price point and make changes very difficult. You can, however combine the system with ADS-B via serial input.

There is a small, lightweight device called the FlarmMouse available which sells for around 600\$ and is only about 40g. It outputs via RS232 serial and uses the NMEA-0183 protocoll. See here:

http://www.lxnav.com/products/flarmmouse.html

http://www.flarm.com/support/manual/FLARM_DataportManual_v5.00E.pdf

I think I'm going to buy one and start experimenting to integrate this in my longer range fpv eqipment... However the price is still a killer for cheaper systems.

But there might be another option, there is a FLARM module available as an option for certain paragliding computers at approx. 100\$:

http://www.flytec.ch/de/produkte/fluginstrumente/flytec-flarm/ueber...

In the last few days have asked both FLARM and the producer of the module, flytec if they could sell these components individually. But FLARM is a sole software company nowadays and flytec, who produces the modules in licence is not willing to do so either. But after some talking with the development manger of FLARM I got the statement that if there is enough interest so that a company - like 3DR would produce the module for the integration in autopilots they would be willing to let them manufacture a custom module based on their licence. Which would mean we could have their core system for maybe 1/5th of the price of a regular system and we can modify certain details (power supply, connectors, GPS interface, etc) which would be nice too...

Regards

Andreas

• This idea will work but it can be made even more powerful and useful using the additional technology of CSMA-CD packet radio. All of the components are available as COTS (Commercial Off The Shelf) items. All that is required is FAA and FCC certification of a prototype system for evaluation. I have suggested such a system and am currently working with a small group of investors and manufacturers to construct a number of prototypes for testing in small aircraft. We estimate a cost of about \$1000 for general aviation devices unless FAA certification and product liability insurance drives the costs higher. The following is a general description of the system we are considering.

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Proposed is a low cost collision avoidance system utilizing GPS and RF CSMA-CD (IEEE 802 type protocol) packet transmission and reception that can be easily installed in any private aircraft as well as large commercial aircraft. No ground based infrastructure is required but can be used to provide augmented information such as weather, airport conditions, etc. The system uses GPS to constantly determine aircraft position, altitude, speed, and course vector. This information is packetized along with Aircraft ID, type, and other essential information. These packets are transmitted to the surrounding area on a single allocated frequency. The packets are received by other aircraft in the area and the position and possible collision parameters are computed and displayed on a screen visible to the pilot. Instructions would be provided to the pilot regarding collision avoidance maneuvers. All aircraft equipped with this device will be able to "see" all other aircraft in the area. The information may also be used to augment air traffic control information for use by air and ground controllers. Automated insitu winds aloft and weather and "PIREPS" (Pilot Reports) can also be accommodated. The device uses COTS components and can be manufactured and sold for a cost under \$1,000.00. The device will be about the same size as a hand held GPS receiver. Power requirements would be on the order of one to two watts. Connections to the aircraft navigation and auto pilot system could improve utility and safety. Adoption of this system would require the assignment of a dedicated radio frequency or set of frequencies.

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If we can get FAA and FCC approval we will build at least ten prototype systems for tests on various kinds of aircraft including small general aviation and business jets. Anyone interested in the project can email me with an inquiry at
chuckivie@hotmail.com
I will prepare an email mailing list and send out new information as it becomes available.

Chuck Ivie
• Ben,

B.S. or not these issues will have to be addressed to the satisfaction of regulators and this must be done in accordance with established procedures.
I totally understand what a royal pisser this is but do we really want government officials to have the authority to issue regulations regarding matters such as this willy nilly and without public review or oversight? I think that is a frightening prospect.
As frustrating as the system is at times it looks like we will have to work with it and jump through the prescribed hoops.
Ira
• Ben,

You have some great ideas but the FAA is legally bound by procedures and can not simply order the requirement for such systems out of hand. There is a lengthy and detailed process they must follow which can be as frustrating to some in the agency as it is to end users.
As someone deeply involved in the sUAS rulemaking process I have learned that even when the agency finally cranks to full steam ahead it will still be years before such things see the light of day.
Any such system will have to be tested and certified and liability issues addressed which will drive up costs.
Not knocking the idea, it could save lives, but if not done right it could also cause reliance on a flawed system and actually cost lives as well so it must be done by the numbers.
With regard small UAS, the real challenge remains objects to be avoided that can't or won't "ping" such as errant party balloons, sea gulls ect when flown over areas where such "encounters" could lead to things falling on people.
The type of system being discussed here has a lot of potential as a first step towards a more comprehensive sense and avoid system but for unfettered use of sUAS in some areas much more will be required.

Ira
• For those who share an undying worship of the homo-sapien as flight coordinator extraordinaire - MSNBC is breaking this story:

BREAKING NEWS: At least 7 killed when medical helicopters collide over Flagstaff, Ariz.

These, and similar news chopper collisions, are exactly the kind of collisions, a near-field peer-to-peer anti-avoidance can resolve. Indeed - the incident-oriented flights are the most likely to collide since they include a motivation to share airspace, and are least likely to be ATC coordinated.

Give it up for the FAA, for bureaucratic rather than mericratic government, and for every one of the GA pilots who have stood in the way of an improved system. I suggest that we carve the name of these "see no progress" Pilots into these seven caskets.

This collision could have been avoided for \$50 in parts from Digikey. I guess that is too much to spend on four pilots and 3 medics.

Benjamin
• Pcas systems are already available for under \$600 and some are capable of interfacing with other devices (flight computers, GPS, moving maps, etc).

http://www.zaon.aero/content/view/2/41/

The problem with the proposed new ATC environment (Under an ADS-B type system) is in its current configuration it is set up for a Ground controller ATC in the loop, my understanding is that in its original configuration tested in Alaska since the late 1990's it functioned independently of ATC sort of peer to peer, ATC if available was just another peer.

The new version (I may be wrong here) broadcasts to ATC and ATC re-broadcasts traffic position data as well as weather, flight hazards and other useful information.

Chris is right about the resistance to tracking equipment being mandated for GA. But the Private Pilots assoc. is now pledging to work with the FAA on a ADS-B type system as long as GA pilots will not be required to carry other types of transponders and the ADS-B system will provide pilots with other useful information and data including charts and weather maps with no charge to pilots. (I can find that link if someone wants to see it).

I think all developers of UAV flight control systems should be designing in the ability to interface with transponder, and other approved systems.

If an Arduino based Auto pilot system could see traffic from the output of a Zaon XRX PCAS it could easily calculate waypoints and an avoidance plan.

If it will talk to a "Pocket PC, Windows Mobile cell-phone, Tablet PC, UMPC, notebook, or selected car-nav system" I think it would not be to hard to build an interface.

http://www.zaon.aero/content/view/85/47/

I think Ben's idea is great but I see no sense in reinventing the wheel and a huge upside to interfacing with systems already in use in the GA community.

We should be designing for the future NOW!
• Over developed areas, yes.
What goes up usually comes down and WHERE it comes down could be a serious issue.
I have personally observed birds (Red Tailed Hawks) attack a small UAS, likely out of concern for a nearby nest.
An operator observing this can take evasive action with his/her system but there is no on board system that can even come close to this capability at this time.
Over a corn field this may not be such an issue. Over a residential area, you can bet it is.

Ira
• These systems should be useful for AG work and such but we should keep in mind that over developed areas none of these systems will suffice for sUAS "Sense and Avoid" unless birds can be convinced to wear them too.

Ira
• I'm surprised that no one has mentioned ADS-B. MITRE has built prototypes of a transmit-only low power unit using cellphone RF components that could cost under \$1000US if built in large enough quantities. Glider pilots in high glider traffic areas use FLARM collision warning systems, which are a bit over \$1000US each. FLARM operates using low power on unlicensed frequencies, it is not a certified collision warning device. They could be sold in the US, but glider vs. glider accidents are rare here, glider vs. any other kind of aircraft is the real worry. The best solution would be a low power VFR-only ADS-B unit using inexpensive non-certified GPS receivers. Hopefully, the FAA can be convinced to accept this idea...
• 100KM
the problem i as i see it is this , the aircraft need to sense its environment and be able to avoid an solid or liquid object weather it be another plane , a flock of birds , a new cell phone tower , trees ect... as mentioned earlier many manned craft will never carry any form of transponder craft like ultralights , hangliders , parachutes , ect...your algorithm im sure works well but you need to put down the sim at some time and get out there and start flying in real airspace and i can assure you that you will find the problem much more complex then what a simple transponder or even some of the audio / video system can deal with at this moment , the fact of the matter is that even humans (which are way more capable at dealing with the unknown then computers ) still get fooled by certain situations all the time . human pilots are still way more capable then your most advanced AP system