Re: [gpsd-dev] [PATCH 7/9] Correctly define autonomous and A-GPS mode

[Greg Troxel]

Sanjeev Gupta <address@hidden> writes:

> On Sat, Apr 18, 2015 at 1:20 AM, Greg Troxel <address@hidden> wrote:
>
>> I don't follow.  If we can figure it out and ensure there are no privacy
>> leaks when getting data,
>
> I checked, I have to register for a "token" with uBlox

That's probably about getting stuff from their servers, and it's bogus
to have to register.  But if we understood, and could get
almanac/ephemeris in and out, it would be simple enough to set up a
server that just had the data, without any registration.

I was more concerned about protocols to get the A-GPS data passing some
estimate of location when they asked.  But identifying the user is an
issue, too.

>> it seems that TTFF could drop from perhaps
>> minutes to seconds.  TTFF can be especially long when there are frequent
>> sky view obstructions.
>>
>
> The GR-801 (ublox M8) datasheet says:
>
> TTFF (Time to First Fix)
> (50%, -130dBm, autonomous)
> Hot Start: 1.5 sec
> Cold Start: 26 sec

Yes, but that assumes solid signal the whole time, which isn't what
happens when you are moving in non-flat terrain.

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