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59

The reason is that there is no member of the general public in those areas with an ADS-B receiver sharing live data with the public tracking sites. Websites like Flight Radar 24 rely largely on volunteers installing ADS-B receivers and sharing their received data. They have a good coverage, but some areas are still not covered.


13

ADS-B is part of a system that compromises a number of different things. ADS-B (In) means that your aircraft is capable of receiving the ADS-B data, FIS-B and TIS-B as well. FIS-B broadcasts information such as weather. TIS-B is a traffic broadcast system. ADS-B includes a number of messages (about 27 different messages), including: Aircraft Identification ...


8

RAIM (Receiver Autonomous Integrity Monitoring) is a function within an avaition GPS receiver. It uses redundant measurements for a consistency check to determine the intergrity of the position measurement. Since RAIM requires redundant measurements, it is only available when there are sufficient measurement sources available. In practice, this mainly ...


8

It depends on the Message Format TYPE Code and the aircraft state. In your example, being on final approach would have no effect as the primary state criteria is being airborne (vs. surface). The rates are 'nominal' rates in that there is a programmed 'dither' to the nominal rate to avoid synchronous garble. The nominal rate for TYPE codes 1 through 4 (ID ...


7

One can easily get lost in the alphabet soup that is datalink. Both ACARS and ADS-B provide datalink applications – which can be broken down in terms of CNS: Communication, Navigation, and Surveillance. ACARS is used for: Communication: includes uplinking (ground → aircraft) weather data upon a downlink request to the company/service provider – not a ...


6

There is not much gained by the third dimension for your use case. In GA you generally want to avoid any active weather. Why make it more complicated? can't go over it (performance limited) can't go under it (microbursts can kill you) => only way is to go around it and therefore no need for that 3D information.


5

It is the true track angle. True means with respect to the geographic North (as opposed to the magnetic North) Track angle means the direction of motion in the horizontal plane (as opposed to heading, which means the direction of the projection of the primary body axis in the horizontal plane). Track angle can be derived from a line joining successive ...


4

DO-260 change 1 is not DO-260A. DO-260A released in April 2003 DO-260A change 1 in June 2006 DO-260A change 2 in December 2006 The releases marked as 'change' contain editorial changes, clarifications and corrections, but are effectively the same specification. The alphabetical versioning is for subsequent releases of a new specification of the same system....


3

The philosophy behind the the quality indicators is that the ADS-B transmitting system sends the data it has, as well as information about the quality of that data. The receiving systems can then decide, based on the quality indicators, whether the data is good enough for their intended application. The reason that more find grained quality indicators were ...


3

The question appears to be asking "Can a non-ADS-B-equipped aircraft legally fly under Class-B airspace shelves that are outside any 30nm Mode-C veil?" Yes it can. See FAR 91.225. The only clause in FAR 91.225 that at first glance might suggest otherwise, is 91.225(d)(3), which states "(d) After January 1, 2020, and unless otherwise authorized by ATC, ...


3

You may fly without ADSB under the Class B or Class C shelf provided you remain outside of any Mode C veil. §91.225 tells you where you cannot fly. It says you cannot fly within the lateral boundaries of the Class B or C airspace or above the airspace. It does not say anything about under the shelf. Here is an example of one such area: skyvector.com You ...


3

Most air traffic control systems nowaday have various safety net functions built into them. Short Term Conflict Alerting is one of these functions. Short Term Conflict Alerting (STCA) works on the basis of extrapolating the current position using velocity and turn rate to predict imminent separation violations. If such a imminent separation violation is ...


3

Data about the height of precipitation would be useful in real-time avoidance of weather phenomena. In fact, this information is provided by NEXRAD and is known as "echo tops." Echo tops also appear in suitably sophisticated SiriusXM weather displays. However, ground based radar is not the primary tool used for weather avoidance, and in particular, ...


3

The danger of VFR flight into IMC is flying into clouds when you aren't properly trained for it. Icing generally only occurs in clouds between -20°C and +5°C. NEXRAD shows the strength of the radar returns, which is usually an indicator of precipitation intensity, though, not clouds, so it doesn't really help avoid either of those things. Regarding why ...


3

My question was due to the confusing mention of ADS-B in what was supposed to be either TIS-B or ADS-R. I've now confirmed that the text on ICAO Doc 9871 Version 2 I quoted was due to a error. In fact DO-260B, and even Doc 9871 Version 2 at table C-37 specify that TIS-B CF=4 is "Fine TIS-B message, AA field contains a 24-bit anonymous aircraft address". ...


3

The AIM covers most of the operations and limitations of TIS-B on page 4-5-18 TIS−B is the broadcast of ATC derived traffic information to ADS−B equipped (1090ES or UAT) aircraft from ground radio stations. The source of this traffic information is derived from ground−based air traffic surveillance sensors. TIS−B service will be available ...


2

From Mode-S.org An ADS-B message is 112 bits long: +--------+--------+-----------+--------------------------+---------+ | DF 5 | ** 3 | ICAO 24 | DATA 56 | PI 24 | +--------+--------+-----------+--------------------------+---------+ DF is the downlink format, ICAO is the 24-bit ICAO identifier of the aircraft, DATA is the message ...


2

This depends on the ADS-B receiver that you have, but if it is still receiving position information, but the WAAS portion is missing, you will get a lower NAC/NIC/SIL in the broadcast message. If you disable the GPS completely, the ADS-B will continue to function however the SIL for position will be the lowest level (likewise for NAC/NIC). The ADS-B will ...


2

As an additional point... the reason ADS was given its own frequencies was so that other communications would not interfere with the needed Position and Identification information sent out via that method. ADS can in many places surplant the need (though I'm not at all suggesting that it should do so) for primary radar. There are too many things that can end ...


2

The content in this FAA link indicates that the answer to the question is "no". Under the rule, ADS-B Out performance will be required to operate in: Class A, B, and C airspace. Class E airspace within the 48 contiguous states and the District of Columbia at and above 10,000 feet MSL, excluding the airspace at and below 2,500 feet above the ...


2

It is deterministic, meaning that if given exactly the same inputs, it will always produce the same output. Your second question is whether it is reversible. The algorithm was deliberately designed to require an adversary to know the precise (i.e. within a few meters) latitude and longitude where the algorithm was run to be able to reverse it. This is ...


2

The link you provided appears to be an article combining ADS-b with Enhanced Mode-S. It has three sections and an intro. The “Track Angle” and “Roll Angle” information is in the Enhanced Mode-S section, and NOT the ADS-b section. Are you asking about the data displayed for the other aircraft displayed on your ADS-b in? The above answer sums it up. ...


1

I have been unable to determine if the Product Registry has been formally relocated or replaced. However, I was able to find all of the relevant information in DO-358A. It wouldn't surprise me if this has become the de facto Product Registry, replacing the FAA website.


1

How is the ADS-b weather derived? If the ATIS is inop, it will usually be because the sensor equipment is inop. If that is the case, how would ADS-b get the data for that airfield? If the sensors are working and the transmitter is inop, you would get the weather directly from ATC. If you were in IMC and/or IFR, your Approach plate would list an alternate ...


1

The display depends on the equipment used. For example, the Avidyne 540 Pilot Guide says this: For Mode-S equipped aircraft, the aircraft ID (e.g. tail number, call sign, etc) may also be displayed adjacent to the traffic symbol. Normally I see a solid white diamond with a dotted line leading away to indicate direction, + or - how many hundreds of ...


1

There are a number of reasons using ADS-B's frequency as a carrier for voice communications isn't a great idea. There are a few issues and factors which I believe you're not taking into consideration which, once understood should illustrate why that is not a workable or desirable solution. First, I'm not going to address this in terms of the UAT system, the ...


1

Ground stations only send ADS-R/TIS-B messages for targets within a certain distance horizontally and vertically of ADS-B targets with the CDTI (Cockpit Display of Traffic Information, aka "ADS-B In") flag set. Assuming your CDTI flag is set correctly, the targets you're missing probably aren't close enough to qualify.


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