DEP has to be standardised so you can assure the designer gets the format and layout of the flight deck correct. There are certification requirements to comply with not opinions.
See
ACAS for full awareness of the capability.
Currently, the only commercially available implementations of ICAO standard for ACAS II (Airborne Collision Avoidance System) is TCAS II
version 7.1 FLARM is relative and co-operative, P-FLARM uses additional data, transponder information. The exploitation of ADS-B out to enhance TCAS II capability is hybrid surveillance but still a variant of ACAS.
The real problem with and ABS-B In solution stems from accuracy of ADS-B Out.
From the FAA:
What are the risks of using an uncertified position source?
The risk for any GPS receiver, when used to support separation services, is how far the position measurement can be in error without detection. If the position error gets large enough, air traffic control would not be able to provide safe separation between your aircraft and other traffic in your vicinity. FAA and our international peers conducted a safety analysis prior to publishing the final ADS-B rule to determine what this error detection boundary should be and the ADS-B performance requirements are based on the results of this safety analysis.
Certified GPS sensors compare GPS satellite measurements against each other. When a satellite signal error becomes large enough to detect, the receiver will reject that signal. The integrity performance specified in the ADS-B rule depends on the proper operation of this error detection feature. It ensures the safety of using ADS-B positioning based on GPSmeasurements.
By comparison, uncertified commercial grade GPS sensors assume the system is working properly and do not attempt to detect errors in the satellite measurements. When presented with an erroneous measurement, they will calculate an erroneous position. This was proven to be an unsafe condition by the FAA's safety analysis. Therefore, ADS-B position based on these sensors was prohibited from being used to support air traffic separation and ADS-B air-to-air operations.
So both TCAS and ADS-B (in and Out) are using certifiable equipment. General Aviation cannot afford the eqpt cost and fights the bureaucracy. Hence the "lightweight" (read cheap, non-assured,) items you get for GA and gliders. You fly these, you take the risks. Unless and until you get "clouted" by the one of the State's aircraft that are also flying in that Class G airspace, fully compliant. The State is easy to attack and the reputation has to be protected hence the attempts to define and install suitable systems in Mil aircraft.
However, UK Mil aircraft do not generally have certifiable eqpt, for lateral or vertical position ie not for RVSM or PBN therefore ADS-B solutions are likely not certifiable. And in some aircraft the height solution does not meet the necessary standard either so anything using the Mode S or 3C transponder ie TCAS may be working on erroneous data, worth noting by those that trust ATC height calls for conflicting aircraft!
Not sure i get either of the points:
Originally Posted by
Lima Juliet
Obviously, TCAS will detect ADS-B Out if it is SIL=1 or above, but those using the Pilot Aware’s GPS for their Mode S ES transponders will pnly be outputting SIL=0.
and
Originally Posted by
Lima Juliet
So many aircraft would see ADS-B if it was SIL=1 or above (ie. from a certified GPS source) and that would include the military.
TCAS II will detect ac that are transponding; Mode3/3c/S but TA/RA will be limited based upon which those modes it sees. As above quality of GPS solution affects ADS-B based ACAS but not TCAS II.
Please explain SIL =1 or above. Are you referring to Def Stan 00-56? SIL 1 is considered the 2nd lowest level in UK Mil Safety Related SW, after SOUP! "SIL1 has a dangerous failure rate band of 10−1 to 10−2 per year)" so not very secure. Civ eqpt manufacturers nearly always use DO-178 and DAL A (highest), down to DAL D or E(SOUP). A system could not be called ADS-B unless it has high a high level of SW assurance, see AC 20-165, "Note: Although the direct effects to your aircraft of an ADS-B failure may be minor, the ADS-B OUT information will be used by other ADS-B IN equipped aircraft and by ATC."
Might also be worth reading
ACAS-X for co-operative system integration into UAS