[time-nuts] Lightsquared and a little math

[Bob Camp]

Hi

There's no decision that they take that they can't reverse. That goes double
for something like this that was done pretty quickly. 

My guess is that they have a limited rather than a full approval at this
point. From the article "proceed with ancillary terrestrial component
operations" does not sound like a full license.

If you do a little Google work on the topic, there are a lot of different
services and outfits impacted by this (not just GPS). None of them are happy
and all of them are likely on the phone to their favorite legislator and /
or lawyers. 

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Pete Lancashire
Sent: Wednesday, February 02, 2011 1:13 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Lightsquared and a little math

Go back to my orig post the FCC has given the go ahead .. to late ?

On Wed, Feb 2, 2011 at 9:57 AM, Bob Camp <lists at rtty.us> wrote:
> Hi
>
> Let's see, a 13 mile circle is pi r squared = ~ 530 square miles.
> 40,000 times 530 is ~ 21 million square miles.
> Wikipedia tells me that the area of the US is 3.79 million square miles.
>
> On that basis, there's not going to be anywhere in the US that you *can*
get
> GPS to fly a plane. Jamming detected = could be a problem = you can't
trust
> it.
>
> I suspect that there indeed will be remote parts of Alaska or the like
that
> you will indeed still have un-jammed coverage in a plane.
>
> Now for the "best case":
>
> 5.6 miles loss of fix = just under 100 square miles. That's 3.94 million
> square miles of jamming. That's still greater than the area of the US. I'm
> sure we'll have some left over to jam Canada and Mexico as well. Again,
> there will be patches where you can get a fix, but they will be the
> exception rather than the rule.
>
> File an IFR flight plan based on any of this - no way. Insure an airline
> that does that - no way. Run an airline based on "VFR only" not going to
> happen. Is everything GPS based - no, but there's a lot of the country
where
> it is.
>
> Not at all clear how you will keep aviation going under those conditions
> unless Lightsquared replaces all their gear with *type accepted*
> replacements. Where do I sign up for my free gps?
>
> Let's suppose they have big pockets and do all that.
>
> At the consumer level, you have 128 thousand square miles with urban
canyon
> issues. Good bet that's every place with an urban canyon in the country.
> Essentially cross off GPS in every large city.
>
> Out here in the sticks, things are a little better. Only a bit over 17
> thousand square miles lost. Except ... do you have any hills or mountains
> near you? Back to the paragraph above if you live anywhere other than
> western Kansas.
>
> Why are they setting this up - to get internet to people. Where are the
> transmitters going - where people live. The consumer numbers may not sound
> as bad, but there's a lot of country that is pretty empty. Look at any
cell
> coverage map to get a good idea how much. You still nuke a lot of voters
> with "only" 17 thousand square miles. Not to mention fire, police, EMS,
and
> the DHL guy.
>
> Then you have the federal law about 911 tracking on cell phones. How does
> that work - GPS. Under what conditions - worse than an urban canyon (no
sky
> at all). You *at least* have the urban canyon area to deal with and likely
> worse. Any bet your cell phone GPS is as RF rugged as the one in your car?
> I'm not taking that bet. Bop up the coverage area a bit more.
>
> So average urban canyon with airborne and what do you get - just a bit
over
> a half million square miles. My guess is that's the whole area of the
> country that has a population dimensioned in multiple people per square
> mile.
>
> So we have:
>
> 1) Multiple Airplanes running into mountains
> 2) Many houses burning to the ground
> 3) Lots of 911 calls getting miss directed and people dying as a result
> 4) Joe six pack getting lost on the way to the beer store
>
> All could be what nukes this. I'm betting on number 4 ...
>
> Bob
>
>
>
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