Tue Jul 09, 2019 10:45 pm #1705144
gaznav wrote:T67M wrote:gaznav wrote:
Before you go Lee, then why not offer an option/module for PAW to emit SIL=0 CAP1391 low-power ADS-B Out? That would shut me up on the subject then?
Are you going to pay for it, gaznav? About half a million pounds should do the job, maybe a million for SIL=1. (Note, that's a very wet finger in the wind estimate, but from my experience in another regulated industry, it's realistic if not a little on the low side.)
£500,000 to develop an ADS-B Out transmitter to this spec: https://publicapps.caa.co.uk/docs/33/CA ... PR2018.pdf
Why so expensive? The GPS that PAW uses should be fine for SIL=0 so you only need to develop a 20W ADS-B Out module. Are you telling me that SkyEcho 2 took £1,000,000 to develop it’s ADS-B Out transmission capability alone? Crikey, uAvionix will need to sell a lot of units to get that money back!! (NB. I doubt they spent that sort of money).
Sorry, I find those figures hard to believe - I’ve asked my brother in law who runs a company that makes datalink equipment for the emergency services. He didn’t talk about anything like that cost to develop something like this. From what I understand, the Declaration of Capability and Conformance process for CAP1391 devices is relatively cheap and straight forward. So where is the significant cost?
Having been involved too in the emergency services, data links, and safety of life systems, I can say that is nothing compared to anything when you add aviation into the mix. Just the product liability insurance is an eye opener.
Just look at some of the standards mentioned in CAP1391, the GPS receiver side is very easy. There are an number out there you can buy off the shelf, some even designed for aviation use, so we can side step that element.
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The technical requirements set out are based on a number of overarching regulations and specifications that many manufacturers will already be familiar with. These include:
Air Navigation: The Air Navigation Order 2016 and Regulations CAP 393 Fifth edition Amendment 1024, as amended and updated from time to time (Statutory Instrument 2016 No. 765 Civil Aviation The Air Navigation Order 2016 is reproduced in full).
British Civil Airworthiness Requirements (BCAR) Section R – Radio Issue 4 April 1974
Commission Implementing Regulation (EU) No 1207/2011 of 22 November 2011, laying down requirements for the performance and the interoperability of surveillance for the single European sky
EASA Certification Specifications CS-23 Amendment 5 Normal, Utility, Aerobatic and Commuter Aeroplanes27 and CS-27 Amendment 3 Small Rotorcraft
ICAO Annex 10 Volume IV Fifth Edition July 2014: Surveillance Radar and Collision Avoidance Systems
RTCA DO-260B/EUROCAE ED-102A with Corrigendum 1, Minimum Operational Performance Standards for 1090MHz Extended Squitter Automatic Dependant Surveillance – Broadcast (ADS-B) and Traffic Information Services – Broadcast (TIS-B) December 2011/January 2012
Physically building an ADSB transmitter is "reasonably" straightforward if you, and /or your team, are OK with FPGAs, RF systems design, power supply design, PCB design and layout, and mechanical design integration. The standards are explicit as to what is needed.
However getting the certification and testing performed, in certified labs, whose results will be accepted in all the various regulatory areas is horrendously, I will repeat that, horrendously expensive. You need to prove, without absolutely no doubt, that in ALL operational and potential failure modes your ADSB transmitter will not impact any other aircraft systems within range. That isn't just the RF side, but also the way it handles and processes data. Ignore data that cannot be right etc. You are testing the hardware and software/firmware.
Heaven forbid you also want to have it actually certified, for the likes of a TSO. Then before you start you need to be a Design Authority (if you're not already, well, you're in for a treat there). You cannot submit a product for TSO approval unless you are, or can work with a company that is who is happy to share the risk with you. For a price. If they trust you.
Certification labs are book months in advance, as you will almost certainly need to do more than one round of testing. Unless you get EVERYTHING perfect first time around. Then there is PCB fabrication and assembly, which all also forms part of your approval. You can't just start building and testing in your lab/office (see below).
Enclosure design will, probably, need some new injection moulds - depending on what you get done where, no doubt with a minimum order run. This also needs testing, proving it doesn't catch fire or emit fumes etc. if it does (or is involved in a fire).
The phrase "only need to develop a 20W ADS-B Out module" is a very simplistic statement for what could have potentially huge impacts to aviation of you get it wrong.
Even a 20W airborne transmitter will have a huge radius of coverage, say 100nm? Imagine if you, through a small error in the design or software, trigger a TCAS alert on 20 airliners. Or go bonkers and 'jam' and ADSB frequencies with rubbish. Have a few bits of error every x cycles of transmission.
(from above) You can't just build one and test it, you need to test it inside an anechoic chamber, or plugged into an ADSB tester/certification unit, in a shielded environment (get your cheque book out for one of these). You will also, almost certainly, have to perform tests in the air with the approval and by arrangement with your local authority, the CAA and NATS here I suppose. To ensure that what is transmitted will work with the systems in the ground, and that you don't cause trouble in the air, so they can help sort the mess out if you do.
You could burn through quite a stack of cash and time to "only .... develop a 20W ADS-B Out module". If you could do it for under £0.75m and a couple of years then get together with few people and get your soldering irons out, you could make a killing selling OEM ADSB-Out modules. You will need a chunk of venture capital, as you won't get any return on investment until it's ready to go, boxes ticked, and paperwork all in order. *
Dropping back to the emergency services for a moment. The new Emergency Services Network (ESN) to replace AirWave, is built using 4G mobile technology. So it should be simple to "just create a communications network, on top of a communication network", shouldn't it? It's years late, and way, way, over budget (£100's of millions over). It's all "standard stuff" but it's more critical than you being able to phone the AA if a wheel comes off. So it takes time, and money, lots of money, to get that right.
* you may have noticed that despite ADSB having been around for quite some time, no one has done this yet. I wonder why?
Last edited by rjc101 on Tue Jul 09, 2019 11:08 pm, edited 2 times in total.
Designer and maker of https://charge4.harkwood.co.uk, smart universal USB power/chargers without the RF interference for EASA GA/LAA