[time-nuts] DHS Resilient PNT Conformance Framework

[Bob kb8tq]

Hi

You can always cycle the power … :)

===========

There also are the basic issues of 50 db gain antennas being attached to
20 db compatible modules. RF rich environments (even without Lightspeed …)
will always be a challenge. Site design *is* part of this “mess”. 

=======

At least from what I saw, *most* modules did a pretty good job of handling the 
stuff they saw. You could always jam them if you had enough power. Most of 
them recovered from that and went back to running correctly. 

Indeed, a device that provided timing on a per band / per system basis would 
probably have taken care of all the issues I saw. Back in the day, those devices
…. not what you got in your low cost module ….

Bob



> On Dec 18, 2020, at 10:44 AM, Magnus Danielson <magnus at rubidium.se> wrote:
> 
> Hi,
> 
> Yeah, so that is why from bitter experience, that needs to be
> recoverable by users in the field. To put it mildly, a pilot flying a
> plane will for sure like to be able to restart a malfunctioning device
> for sure. Sure, it can take a few minutes, but being able to recover to
> a known state with a known command (similar enough to the three-finger
> salute of Ctrl-Alt-Del) is worth plenty. Loosing the capability to
> navigate for the rest of the flight and in fact ground the plane until
> unit can be replaced is.... something they want to avoid for sure.
> 
> I think we all are happy that then do not think it's a good idea to take
> an instrument out, attach JTAG and reprogram it with a flimsy Windows
> laptop mid-flight. Right? Right.
> 
> Cheers,
> Magnus
> 
> 
> On 2020-12-17 23:55, Bob kb8tq wrote:
>> Hi
>> 
>> Gee, GPS modules that go nuts and stay nuts after getting hit with this or that.
>> I haven’t seen any of that since I retired …. :)
>> 
>> Bob
>> 
>>> On Dec 17, 2020, at 5:30 PM, Magnus Danielson <magnus at rubidium.se> wrote:
>>> 
>>> Hi Bob,
>>> 
>>> Yes, there is that too. NIST insisted to have me involved, so I got
>>> involved.
>>> 
>>> This is pretty high level, because it was needed, but many low-level
>>> details was discussed and then we backed out with that common ground.
>>> Some of the IT-security approaches does not really work on the
>>> RF-interface. It's not that it can't be hacked, but it works so
>>> differently and with much lower bit-rate... and one-way, that the
>>> security analysis becomes quite different about how attacks can be done.
>>> After that we concluded it's good to mention, but this is not relevant
>>> for all interfaces. :)
>>> 
>>> There is many ways to achieve the different levels, but we wanted to
>>> make a number of key rules to sort things out, they form a form of
>>> minimum set of requirements. Normal receivers achieve level 0.
>>> 
>>> Some receivers "hang" after being upset by some input. "hang" to the
>>> level it needs vendor intervention. So one learning is that the user
>>> must be able to force the receiver into a "known state".
>>> 
>>> Cheers,
>>> Magnus
>>> 
>>> On 2020-12-17 19:50, Bob kb8tq wrote:
>>>> Hi
>>>> 
>>>> Pretty suspicious looking list of contributors. Very much so about half way
>>>> down the list :) …. congratulations !!! ( I guess …)
>>>> 
>>>> Bob
>>>> 
>>>>> On Dec 17, 2020, at 12:52 PM, Magnus Danielson <magnus at rubidium.se> wrote:
>>>>> 
>>>>> Fellow time-nuts,
>>>>> 
>>>>> DHS just published the work on Resilient PNT Conformance Framework, that
>>>>> has been in the works since last year. This is intended to be the
>>>>> framework for which multiple sectors align their standards, and a wide
>>>>> range of interest was involved.
>>>>> 
>>>>> Hope it can be interesting reading for you.
>>>>> 
>>>>> https://www.dhs.gov/publication/st-resilient-pnt-conformance-framework
>>>>> 
>>>>> Cheers,
>>>>> Magnus
>>>>> 
>>>>> 
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