[pcap-ng-format] Proposing new block type for PCAP-NG (UNCLASSIFIED)

[Guy Harris]

On Apr 8, 2015, at 9:43 AM, "Renard, Kenneth D CIV USARMY ARL (US)" <kenneth.d.renard.civ at mail.mil> wrote:

>>> o  Source Types are an enumerated type with a defined list such as:
>>> 
>>>    0     Undefined source
>>>    1     GPS
>>>    2     3GPP
>>>    3     INS
>>>    [...]
>> 
>> What is "3GPP" as a source type?
> 
> Simply a place-holder for some 3GPP-related location provider.

I'm not sure that there's a single such provider.  One provider the standards Anders mentioned is GPS.  My inclination would not be to put place-holders in, but to put in entries for location providers that are known.

>> Does "GPS" mean "some global navigation satellite system", in
>> which case it should probably be called "GNSS", or does it
>> specifically mean "the US Global Positioning System", in which
>> case we also would want type values for GLONASS, Galileo, BeiDou,
>> IRNSS, and any others I haven't mentioned because they're not
>> listed in
> 
> GNSS would be fine.  I think GPS is a common term in the US that
> Would be well understood as a source of positioning information.

I guess the question is whether we want to indicate what generic sort of source we have, in which case "GNSS" would be appropriate and used for any GNSS (GPS, Galileo, GLONASS, BeiDou, IRNSS, etc.) - I'd prefer not to have the standard seem US-centric by using "GPS" to mean "GNSS" - or we want to indicate the *specific* source, in which case we'd have GPS for the US system, GLONASS for the Russian system, etc..

If we're indicating the generic source, we could, for GNSS, have an indication of which GNSS as another datum.

>> If so, I might be tempted to have separate options for a UTF-8
>> descriptive string, presumably intended for human consumption,
>> and an actual 3D coordinate value, for computer consumption.
> 
> Sounds reasonable.  Change Location/Orientation Provider Block option
> ["lp_origin", variable, UTF-8] to 2 options:
> 
>  ["lp_origin_description", variable, UTF-8]
>  ["lp_origin_lla", 12bytes, 3 32-bit signed ints]

Presumably millionths of a degree for longitude and latitude and meters relative to something for altitude.