tree 9c808d123c773b3d13d7fe9fc82121ddefafce29
parent 87c3afb5a969838446433c6d0d0ece8e9821e2c0
author Neels Hofmeyr <neels@hofmeyr.de> 1600444850 +0200
committer Neels Hofmeyr <neels@hofmeyr.de> 1602070786 +0000

add GAD coding for Location Services

GAD, Universal Geographical Area Description:
- raw coding for all GAD elements.
- SI-units encoding and decoding for Ellipsoid point with uncertainty circle,
  which I presume is the typical "at most N meters away from cell tower located
  at X,Y", which corresponds to the TA positioning currently being implemented.
- other SI-units GAD element encodings are so far not implemented.

Add encoding and decoding tests.

In gsm/protocol/gsm_23_032.h are the raw coding structs as defined in 3GPP TS
23.032.

In gsm/gad.h are structs carrying consistent units based on meters and degrees,
for convenient / less error prone handling of GAD data, and for human readable
representations of the GAD data.

The separation of the two is desirable because OsmoBSC will receive GAD data
from OsmoSMLC on the Lb interface, and pass on this data to the MSC via the A
interface. It is better to pass the GAD data as-is without de/encoding.

Change-Id: I7a9dd805a91b1ebb6353bde0cd169218acbf223c