Newbie question - Odd patterns in data?

1 year 20 hours ago - 1 year 20 hours ago #1753 by jkaplan
In running queries on a geofenced location in the San Francisco Bay Area around airport KHAF, in the table state_vectors_data4, I'm having trouble interpreting the data.

I get long runs of state_vectors with increasing times for any given aircraft (icao24), where the rest of the data - lon, lat, velocity, etc. are identical. The timestamps from the start of the runs to the ends can be 5 minutes or more. Then there are occasional "skips" of as much as 30 minutes before the next record, while the aircraft has apparently moved only a few hundred feet or so. 

For example, here's a run starting at 1641094994 and ending at 1641095296 for ade9b8. I believe this is a span of 302 seconds?

1641094994 | ade9b8 | 37.47161865234375 | -122.4527176566746 | 61.94939689053588 | 322.0832859997525 | -0.32512 | N996JC   | false    | false | false | 7131   | 281.94       | 335.28      | 1641094993.963 | 1641094993.963 | 1641092400 |

| 1641094995 | ade9b8 | 37.47161865234375 | -122.4527176566746 | 61.94939689053588 | 322.0832859997525 | -0.32512 | N996JC   | false    | false | false | 7131   | 281.94       | 335.28      | 1641094993.963 | 1641094994.267 | 1641092400 |

| 1641094996 | ade9b8 | 37.47161865234375 | -122.4527176566746 | 61.94939689053588 | 322.0832859997525 | -0.32512 | N996JC   | false    | false | false | 7131   | 281.94       | 335.28      | 1641094993.963 | 1641094994.267 | 1641092400 |

| 1641094997 | ade9b8 | 37.47301521947828 | -122.4540909476902 | 61.94939689053588 | 322.0832859997525 | -0.32512 | N996JC   | false    | false | false | 7131   | 259.08       | 335.28      | 1641094996.889 | 1641094996.889 | 1641092400 |

…   [edited]

1641095294 | ade9b8 | 37.47301521947828 | -122.4540909476902 | 61.94939689053588 | 322.0832859997525 | -0.32512 | N996JC   | false    | false | false | 7131   | 259.08       | 335.28      | 1641094996.889 | 1641094996.889 | 1641092400 |

| 1641095295 | ade9b8 | 37.47301521947828 | -122.4540909476902 | 61.94939689053588 | 322.0832859997525 | -0.32512 | N996JC   | false    | false | false | 7131   | 259.08       | 335.28      | 1641094996.889 | 1641094996.889 | 1641092400 |

| 1641095296 | ade9b8 | 37.47301521947828 | -122.4540909476902 | 61.94939689053588 | 322.0832859997525 | -0.32512 | N996JC   | false    | false | false | 7131   | 259.08       | 335.28      | 1641094996.889 | 1641094996.889 | 1641092400 |

Of course the plane wasn't standing still, so I must misunderstand the data in some way. Any help would be appreciated!

Jerry

PS - The actual query that produced this data is:
select * from state_vectors_data4 where hour>=1641024000 and hour<1641542400 and lat>=37.45 and lat<=37.55 and lon<=-122.43 and lon>=-122.53 and baroaltitude<=300 order by icao24,time;




 

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1 year 9 hours ago #1755 by strohmeier
Hi,

This plane will have left our coverage, as indicated by the lastcontact/lastposupdate column. It remains in the state vectors for a while with the last state before it is dropped.

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