Invalid epos (Distance caculator from homepos?)

[kiwiscout]

In the logs I'm seeing the following being produced. With no correct distance calc - related to me being in the southern hemisphere or an offset calculation for latitude?

20:52:39.177: addr C81AC0: Invalid epos: +172.710 lon, +133.144 lat from heading: -138.0. delta_X: -164.570, delta_Y: -182.773. 20:52:39.458: addr C81AC0: Invalid epos: +172.708 lon, +133.145 lat from heading: -138.0. delta_X: -54.724, delta_Y: -60.778. 20:52:40.586: addr C81AC0: Invalid epos: +172.708 lon, +133.145 lat from heading: -138.0. delta_X: -111.432, delta_Y: -123.757. 20:52:40.866: addr C81AC0: Invalid epos: +172.706 lon, +133.146 lat from heading: -138.0. delta_X: -55.121, delta_Y: -61.218.

At first I thought it was my lat/long settings so triple checked those (I think the readme potentially has the example format backwards?)

If a config-setting homepos = longitude,latitude setting is defined, the distance to the place gets calculated. I.e. the Dist column above. E.g. a homepos = 60.3016821,5.3208769 for Bergen/Norway.

Which is lat 60 long 5?

[gvanem]

If a config-setting homepos = longitude,latitude setting is defined,

Yes, that's backward. Should be homepos = latitude,longitude ... (the name longitude comes from the length of the Mediterranean Sea).

I also have some problems with the decoding of the CPR in some cases; I assume that's where you're problem also comes from.

I replayed this flight: https://planefinder.net/data/flight/NZ5798/history/5-5651005 to get a clue.

There could be a problem with a too simple cartesian_to_spherical() and the use of atan2() in this case. You're in New-Zealand (no?). So the estimated position should be close to +172.710 lon, -46.856 lat. Somewhere there is a missing mapping to [-90, 90] for latitude.

[gvanem]

I have a long list of commits that now seems to have fixed this. The CPR stuff is completely rewritten thanks to Dump1090-FA and Dump1090-RSP. Stay tuned for those git push updates.

[kiwiscout]

If I can grab some more data or test something let me know if one of those recent ones was meant to help.

As unfortunately.. 00:23:58.804: plane C82759: Invalid epos: +172.515 lon, +133.069 lat from heading: +100.0. delta_X: +110.110, delta_Y: -19.415.

[gvanem]

Some issue with this in geo.c:

  _pos.lat = 180.0 * atan2 (h, cart->c_z) / M_PI;

h should be -h I think in your case. Try it.

[gvanem]

I'm disabling the call to aircraft_set_est_home_distance() until I figure out what's wrong. So this issue is no longer relevant in the next commit.

[gvanem]

Since cartesian_to_spherical() is no longer called, this issue seems non-existent. Closing.