bugGPSD - Bugs: bug #49175, AIS AIVDM data not correctly...


bug #49175: AIS AIVDM data not correctly decoded

Submitted by:  Andreas Bals <abad>
Submitted on:  Sat 24 Sep 2016 03:38:02 PM UTC  
Votes:  2  
Category: NoneSeverity: 3 - Normal
Item Group: NoneStatus: None
Privacy: PublicAssigned to: None
Open/Closed: Open

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Wed 06 Sep 2017 01:44:00 AM UTC, comment #1:

Andreas, please review the three divisors at gps.h line 898, and the code at gpsd_json.c around line 1628. It appears to be doing the exact division you specify.

Are you lookig at some output other than JSON?

Eric S. Raymond <esr>
Project Administrator
Sat 24 Sep 2016 03:38:02 PM UTC, original submission:

Input string:


GPSD tranlates it nearly correctly into:
211673150, -, 30416097, 4305075, 3600, 511, 0, -128, , 1
(MMSI, imo, lat, lon, couse, heading, speed, turn, callsign, type)

Unfortunately one processing step on lon/lat is missing.
AIVD-lon/lat is given in minutes * 10'000.

In order to get location in degrees you have to divide by (10'000 * 60):
30416097/(600'000) = 50.693495 deg lat
4305075/(600'000) = 7.175125 deg lon

Andreas Bals <abad>


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    Date Changed By Updated Field Previous Value => Replaced By
    Mon 26 Sep 2016 07:37:21 PM UTCabadCarbon-Copy-=>Added abad

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