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Comment Re:Turn key back on? (Score 1) 350

just the old Navstar satellites which were in polar orbit so didn't provide fixes very often if you were near the equator.

Sorry, but why do you get fewer fixes near the equator? Were the orbits set up with apogee over the poles to provide more "hang time" in polar areas? I guess such a system would have been optimised for navigating nuclear-loaded bombers to their targets flying over the North Polar regions. It's not as if the system was designed for civilian convenience, after all.

No, the satellites were in polar orbits, which means they orbited in north-south direction following a particular meridian. Picture the meridians: they are further apart at the equator than the poles, hence fewer fixes.

Comment Re:Turn key back on? (Score 1) 350

Practice is key. When I was at sea in the 70's and 80's, we didn't have GPS, just the old Navstar satellites which were in polar orbit so didn't provide fixes very often if you were near the equator. Company regulations were that noon position was fixed by sun sights in the morning combined with latitude observation at noon, and fix by star sights at morning and evening twilight. After a while it becomes so routine you can almost do it in your sleep. Today I wouldn't go to sea without paper charts, almanac, Norie's or Burton's tables and a good supply of 2B pencils, not because I don't like GPS, but because I can't trust something provided by a government which may be switched off at any time for any reason.

Comment Forensic evidence should not be subjective (Score 5, Insightful) 173

The same thing happened some years back with fingerprint evidence. The people who are responsible for the analysis of forensic evidence should be 'blind', i.e. they should not have access to the context of the case. If they are given two fingerprints to match, they should merely be asked whether or not they are a match, and not told where they come from or even which case they pertain to. Then there would be far less bias. Also, they should not testify in trials, merely issue an affidavit of their results.

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