AISAT "Too short mic-e packet"
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edfa...@gmail.com
Apr 29, 2019, 3:17:05 PM4/29/19
to aprs.fi
There's a new digipeater in space using ARISS paths. Unfortunately their implementation is a bit odd as defined here:
While packets show up here:
They show up on aprs.fi with an error:
I don't know how long AISAT-1 will be in orbit, but it has the strongest aprs signal in space right now. The ISS and PSAT are both... poor. Is there a way to accommodate the odd packet for this station on aprs.fi?
thanks,
-craig
Heikki Hannikainen
Apr 29, 2019, 3:28:53 PM4/29/19
to aprs.fi
Hi,
I'm aware of the issues. It's been discussed on the APRSSIG; I'm on the
same lines with Steve Dimse (findu) and John Langner (direwolf):
http://lists.tapr.org/pipermail/aprssig_lists.tapr.org/2019-April/047995.html
http://lists.tapr.org/pipermail/aprssig_lists.tapr.org/2019-April/047996.html
http://lists.tapr.org/pipermail/aprssig_lists.tapr.org/2019-April/047997.html
The satellite breaks the AX.25 and APRS protocols in many ways. iGates
which properly validate AX.25 protocol compliance (most igates) will not
even pass those packets to the APRS-IS. Apparently there is a broken
igate out there now, passing them to APRS-IS with some modifications.
The makers of the satellite apparently did not test their software in any
way for protocol compliance, and still chose to write their own
implementation instead of using someone else's open source code which
would have been known to work.
I do not plan to make any changes to work around their bugs; they should
fix the bugs in their firmware and upload a fixed build.
aprs.fi *correctly* shows that the packets are broken, and I won't change
that.
Sorry!
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- Hessu
Heikki Hannikainen
Apr 30, 2019, 2:44:18 AM4/30/19
to Ed Fardos, apr...@googlegroups.com
On Mon, 29 Apr 2019, Ed Fardos wrote:
> Cool, thanks for the investigation. It's not like we can fix every igate.
It's not a "fix", it means *breaking* the igate.
An igate must not modify packets. That will cause modified duplicate
packets on the network, as the modifications done by igates will likely be
slightly different, and not all igates will do them.
> I'm not even sure AISAT has a firmware update process, and yes, evidently
> aprs was a last minute design requirement (like a few days before launch),
> so it's somewhat glitchy (understatement?) as expected.
In such a hurry, one should put all effort on the firmware update
process, and leave implementing APRS after the launch. If one does not
have firmware upgrade, there will be no way to fix bugs. A software
release always has bugs, and such a hurried and untested release will have
a lot of them. If you can't update software on a device, you're generally
screwed, even if it isn't a satellite.
- Hessu
> Cool, thanks for the investigation. It's not like we can fix every igate.
It's not a "fix", it means *breaking* the igate.
An igate must not modify packets. That will cause modified duplicate
packets on the network, as the modifications done by igates will likely be
slightly different, and not all igates will do them.
> I'm not even sure AISAT has a firmware update process, and yes, evidently
> aprs was a last minute design requirement (like a few days before launch),
> so it's somewhat glitchy (understatement?) as expected.
In such a hurry, one should put all effort on the firmware update
process, and leave implementing APRS after the launch. If one does not
have firmware upgrade, there will be no way to fix bugs. A software
release always has bugs, and such a hurried and untested release will have
a lot of them. If you can't update software on a device, you're generally
screwed, even if it isn't a satellite.
- Hessu
Ed Fardos
May 1, 2019, 2:06:51 AM5/1/19
to apr...@googlegroups.com, Heikki Hannikainen
Cool, thanks for the investigation. It's not like we can fix every igate.
I'm not even sure AISAT has a firmware update process, and yes, evidently
aprs was a last minute design requirement (like a few days before launch),
so it's somewhat glitchy (understatement?) as expected.
best,
aprs was a last minute design requirement (like a few days before launch),
so it's somewhat glitchy (understatement?) as expected.
-craig
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