dump1090-mutability (1.14)

• Position reporting:
  • Use the correct maximum inter-position-message intervals for surface
    position messages (github issue #18).
  • Disable receiver-relative position decoding entirely if the receiver
    max range is larger than 360NM.
  • Implement speed checks on position updates; implausible position
    changes are discarded, unless they improve NUCp. Fixes most cases
    of "spikes" in position tracks for aircraft with poor GPS data, and
    helps with many cases where aircraft are transmitting garbage position
    data. (github issue #17)
  • If a position update is considered implausible, discard all the other
    data in the same message too, just in case - often altitude will be
    wrong in this case, too.
• Message decoding/forwarding:
  • NUCp (navigational uncertainty) is extracted from position messages
    (github issue #16)
  • Improved support for DF18 ADS-R/TIS-B message formats and
    cases where they use non-ICAO addresses (handle the IMF bit)
  • Don't forward the first message for an aircraft to network clients
    until we have seen a second message from the same aircraft.
    This should handle most of the "garbage ICAO address" cases.
    Disabled in --net-verbatim mode.
  • Aircraft with only one message seen are pruned more aggressively
    (60 second timeout vs. 300 second timeout normally)
  • Don't emit SBS output for non-ICAO addresses (github issue #9)
  • Improved the calculation of message reception time seen in SBS output.
    Now message reception time should be strictly before current time.
  • Don't try to correct more than one error in DF11 messages as these
    messages have reduced CRC coverage and multiple-bit errors are
    ambiguous.
  • Fix some undecodable altitudes that would be interpreted as a valid
    altitude of 0ft.
• Stats & JSON:
  • Documented the JSON formats (see README-json.md)
  • Fix "-infdB" in stats if no signal peaks have been recorded.
  • NUCp is reported in aircraft.json
  • Fix "unrecognised ICAO address" stat counter to count the right thing.
  • Gather stats on number of unique aircraft tracks seen, and number of
    tracks where only a single message was seen (which are probably
    garbage).
  • Fix stats timestamp output during the period shortly after restart.
  • Include timezone in timestamps shown with --stats
  • Add various stats for CPR position-decoding details.
• Webmap:
  • Fix webmap history loading when no history is present.
  • Better handling of long refresh times in the webmap.
• Packaging/misc:
  • Fix config handling of lat/lon between -0.999 and 0 (github issue #14)
  • Add --oversample option to help text (github issue #11)
  • More options now accept fractional seconds (--stats-every,
    --net-heartbeat, --net-ro-interval, --write-json-every)
  • Start dump1090 with a niceness of -5 to reduce the chance of dropped
    sample data, except in --net-only mode where it's not using a RTLSDR
    dongle (github issue #19)
  • Make sure background tasks have a chance to run even if the sample rx
    thread is blocked waiting for a USB reconnect. (github issue #20)
  • Include timestamps in logging of USB disconnects/reconnects (github
    issue #21)
  • Catch SIGTERM and do clean shutdown like SIGINT does. Also log about
    it. (github issue #22)
  • Log (with timestamps) on startup/shutdown so it's more obvious in logs
    where dump1090 restarted.
  • Mark all HTML/Javascript as conffiles to avoid overwriting user changes
    on package upgrade, as many people seem to modify these files.
    (github issue #15)