Wed 30 Aug 2006
Current GPS constellation questioned
Posted by glenn under Satellite
GPS World reports:
The current GPS constellation — its health and viability — continues in question and under scrutiny, despite reassurances from the Air Force.
Last month’s GPS World Survey & Construction e-newsletter relayed user plaints that there aren’t enough healthy GPS satellites. Surveyors say they can’t use RTK a full day with the current constellation even with every satellite healthy — and that recently there have been more satellite outages than ever before. They’ve resorted to filling GPS gaps with GLONASS.
The online story drew immediate affirmation. “While most of the time we get good coverage, for the last couple months we have had a 4 to 6-hour gap where we ‘float’ a lot and our precision goes down. Unfortunately this gap is usually between 10 am and 2 pm, which creates some interesting scheduling problems.”
Thu 24 Aug 2006
Posted by glenn under Government
Bruce Schneier writes:
I’d like everyone to take a deep breath and listen for a minute.
The point of terrorism is to cause terror, sometimes to further a political goal and sometimes out of sheer hatred. The people terrorists kill are not the targets; they are collateral damage. And blowing up planes, trains, markets or buses is not the goal; those are just tactics. The real targets of terrorism are the rest of us: the billions of us who are not killed but are terrorized because of the killing. The real point of terrorism is not the act itself, but our reaction to the act.
And we’re doing exactly what the terrorists want.
Fri 11 Aug 2006
Posted by glenn under Humor
On Yahoo’s MI_BM list, Dan E. writes:
Mandatory nude flights.
It’s the only logical solution to this problem.
Tue 8 Aug 2006
Posted by glenn under General
On the Time-Nuts mailing list, [email protected]… writes
Sorry to post again, but it just dawned on me that I meant to post some
info concerning M12+, M12, GT, UT+, and probably even VP receivers. This
issue is one of the reasons the M12M is late coming out of the chute. If
I have posted this before I apologize. Just too many things rattling
around in my brain.
CRITICAL: Whenever you run a Self-Test on any of these receivers, MAKE
ABSOLUTELY SURE that you wait until you have gotten the response message
before you issue any additional commands. If you get REALLY lucky and
send your command at EXACTLY the wrong time while the UART is in limbo
you can get stuck in a lovely “do…while” loop that can only be exited
by cycling power to the receiver. A clue that this has occurred is that
the 1PPS also stops. The Self-Test code in the M12M has been changed to
keep this from happening.
Looking back, this explains a lot of the unexplained random failures in
cell towers reported over the years by a couple of the carriers.
Absolutely unrepeatable. Almost impossible to troubleshoot. We just
found it by accident.
Now, before any of you wise guys try to repeat this problem, bear in
mind that statistically it seems to happen maybe once per 200,000 Self
Mon 7 Aug 2006
Posted by glenn under Internet
On Slashdot, alien88 writes:
“Late last week, the Washtenaw County Board approved Wireless Washtenaw Advisory Board’s recommendation of 20/20 Communications to cover the entire county with wireless by the end of 2007. This includes Ann Arbor, the home of University of Michigan and future home of Google’s Adwords division. The wireless network will be free for speeds up to 85kbps and $35/month for 500kbps. 20/20 Communications estimates it will take around 6,000 radios to cover the county.
This initiative is being funded without taxpayer dollars and is one of the most ambitious wireless deployments in the US. Will it succeed or will it fail? Check out the county’s wireless website for updates on the project.” Of course, the real reason this is worth posting is it’s because this is the county where Rob, myself and a number of the others live in.
Tue 1 Aug 2006
Posted by glenn under Info Tech
I just got a Nokia E61 on T-Mobile. When I signed up, I knew that the signal was really weak in the back of our house - the building forms a large square, and my bedroom faces into the centre of the square. I could get a signal in the living room (just), but wouldn’t it be great, I thought, not to have to go through there every time the phone rings. Although outside my house full-strength UMTS signals are readily available, the building’s construction prevents them diffracting into the internal ‘courtyard’.