It sounds like time is going backwards.http://science.slashdot.org/story/15/10/17/2254250/naval-academy-reinstates-teaching-of-celestial-navigation
/. Naval Academy Reinstates Teaching of Celestial Navigation
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I think because last week they had a bug and their electronic nav went down and all of a sudden they had to find someone that knew how to use a sextant"n4lbl alan.schulman@... [AlbinVega]" AlbinVega@yahoogroups.com wrote:
It sounds like time is going backwards.http://science.slashdot.org/story/15/10/17/2254250/naval-academy-reinstates-teaching-of-celestial-navigation
It sounds like time is going backwards.http://science.slashdot.org/story/15/10/17/2254250/naval-academy-reinstates-teaching-of-celestial-navigation
Many years ago a buddy on a tour boat on the Mekong River found his GPS indicating that they were in the S. China Sea. The probable explanation was that the military base they were near employed spoofing.Sometimes you can't test everything in a lab. GPS software used to be tested "over" White Sands NM which may still be true. The FAA issued notices to airmen to avoid use of GPSs in that vicinity. The test satellite would only operate within the announced bounds. I'd like to understand how they can effect such a small geographical area.
First, full disclosure: I teach advanced coastal navigation and have taught celestial in the past (as well as helping write a course on it). There are many articles on the internet on what the Navy is doing. But I submit that any fool, with too much money, can buy a computer or plotter and think they are a great navigator (Too much money, too much boat so the saying goes).But, having spent thousands of hours thrashing about in small boats in blue water, I have always been a proponent of knowing celestial navigation. The reason stated by the Navy is the increasing danger of cyber attacks wiping out GPS. However, for the small boat it is often the electronics or electrical generating system itself that is the problem. I have had computers quit when offshore (I always carried a backup) and have worked on more than one boat whose electrical system died on a crossing. I dare submit that many of the really serious offshore cruisers still carry a sextant and most have had at least one course in reducing a sight (at the very least a Noon Position).Finally, having a sailboat is considered by many to "be going backwards." In the day of powerful cruising diesel trawlers, many capable of circumnavigating, that argument is made (I belong to an organization where there are many folks with very large trawlers (as well as many with sailboats)). Personally I kind of like doing things in a traditional manner.Finally, this statement really hit home -- it is one of the final statements in one of the article attached. “Knowledge of celestial navigation in the GPS era provides a solid back-up form of navigation in the event GPS becomes unreliable for whatever reason. It is also good professional practice to use one navigational system to verify the accuracy of another.”Military Daily News Brown"All you need in this life is ignorance and confidence; then success is sure." - Mark Twain
Sorry I did sound rather accusatory -- didn't mean what I said to "attack" what you said.But as you said in your follow-up, going back to the traditional methods, or learning some of them, really helps in understanding and using electronic navigation techniques. Being able to plot a course with nothing more than a compass and a chart (and the pencil, plotter and divider) gives one a better understanding of what is going on. I once had a student in one of my coastal classes say to me that he wasn't going to take the next course, a celestial course, as he wasn't going to be going anywhere offshore. I encouraged him to do so and he took not one, but then a second.A year later we were chatting over lunch and he thanked me for encouraging him to take the traditional celestial course. He had just returned from a few weeks of cruising the San Juans and the Gulf Islands. Though never far from land, he said that having taken the celestial courses really gave him a better understanding of entire picture -- he developed a broader understanding I guess. He said he enjoyed the experience so much more. And when I was out cruising across some ocean or whatever, I usually had all kinds of time on my hands and got tired or reading or repairing something. Taking and reducing sights was a good mental exercise actually -- and I found it fun to do. I was always pleased when my traditional methods would compare favorably with my GPS(s) and plotter. I would use several of the different sight reduction methods even (I once tried reducing some sights using logarithms and have to say that was a lot of work though -- never tried using a slide rule, but have thought about it). Chris Brown"All you need in this life is ignorance and confidence; then success is sure." - Mark Twain
Well said, both of you. eBay usually has very affordable sextants. WaltTo: AlbinVega@yahoogroups.comFrom: AlbinVega@yahoogroups.comDate: Sun, 18 Oct 2015 13:25:28 -0600Subject: Re: [AlbinVega] /. Naval Academy Reinstates Teaching of Celestial Navigation
I didn't realize it but I said wasn't even ambiguous. I didn't say what I meant at all. By time going backwards I meant back to the time when we recognized the need for the whole skill-set, and paper maps too.
I didn't realize it but I said wasn't even ambiguous. I didn't say what I meant at all. By time going backwards I meant back to the time when we recognized the need for the whole skill-set, and paper maps too.
I don't want to belabor this, but since it was asked.A GPS signal can be corrupted by two means. Spoofing as was mentioned and jamming. With a GPS signal it is pretty easy to do if one is in the general vicinity of the receiver since the GPS signal is really weak (in one journal I was reading it was likened in strength to taking a 25 watt light bulb 10,000 miles into space, then trying to see if from earth). I am sure many of you have experienced this weak signal when trying to receive a signal in an enclosed space. As some of the older satellites are being retired, I understand they are being replaced with higher power signals. So, jamming is just that, blasting a disruptive high powered signal (noise) at the same frequency and blotting out the real signal (or overwhelming the receiver if you will). As for spoofing, this is also sending a much stronger signal, but this time substituting inaccurate data for the real data. The GPS receiver will often (usually) go with the stronger signal and thus its algorithm will put you at the wrong place in your readings or CP. Interesting enough there are other systems that you may have heard about I am sure. Glosnos is the Russian system, Galileo is a EU system (I believe mostly French driven), a Chinese system with a name that I can spell or pronounce, and even an Indian system (however this is pretty much limited to their own geographic territory). It was asked once why would these foreign governments go to all the expense when GPS has world wide coverage: well if you were any government other than the USA, would you be comfortable with a nav. system controlled and operated by the U.S. Air Force????Chris Brown"All you need in this life is ignorance and confidence; then success is sure." - Mark Twain
Any natural causes or incidental man made causes? We recently took our camper to a campground whose directions indicated that the gps signals were not reliable there. Thanks, WaltTo: AlbinVega@yahoogroups.comFrom: AlbinVega@yahoogroups.comDate: Sun, 18 Oct 2015 22:22:27 -0700Subject: Re: [AlbinVega] /. Naval Academy Reinstates Teaching of Celestial Navigation
I don't want to belabor this, but since it was asked.A GPS signal can be corrupted by two means. Spoofing as was mentioned and jamming. With a GPS signal it is pretty easy to do if one is in the general vicinity of the receiver since the GPS signal is really weak (in one journal I was reading it was likened in strength to taking a 25 watt light bulb 10,000 miles into space, then trying to see if from earth). I am sure many of you have experienced this weak signal when trying to receive a signal in an enclosed space. As some of the older satellites are being retired, I understand they are being replaced with higher power signals. So, jamming is just that, blasting a disruptive high powered signal (noise) at the same frequency and blotting out the real signal (or overwhelming the receiver if you will). As for spoofing, this is also sending a much stronger signal, but this time substituting inaccurate data for the real data. The GPS receiver will often (usually) go with the stronger signal and thus its algorithm will put you at the wrong place in your readings or CP. Interesting enough there are other systems that you may have heard about I am sure. Glosnos is the Russian system, Galileo is a EU system (I believe mostly French driven), a Chinese system with a name that I can spell or pronounce, and even an Indian system (however this is pretty much limited to their own geographic territory). It was asked once why would these foreign governments go to all the expense when GPS has world wide coverage: well if you were any government other than the USA, would you be comfortable with a nav. system controlled and operated by the U.S. Air Force????Chris Brown"All you need in this life is ignorance and confidence; then success is sure." - Mark Twain
I don't want to belabor this, but since it was asked.A GPS signal can be corrupted by two means. Spoofing as was mentioned and jamming. With a GPS signal it is pretty easy to do if one is in the general vicinity of the receiver since the GPS signal is really weak (in one journal I was reading it was likened in strength to taking a 25 watt light bulb 10,000 miles into space, then trying to see if from earth). I am sure many of you have experienced this weak signal when trying to receive a signal in an enclosed space. As some of the older satellites are being retired, I understand they are being replaced with higher power signals. So, jamming is just that, blasting a disruptive high powered signal (noise) at the same frequency and blotting out the real signal (or overwhelming the receiver if you will). As for spoofing, this is also sending a much stronger signal, but this time substituting inaccurate data for the real data. The GPS receiver will often (usually) go with the stronger signal and thus its algorithm will put you at the wrong place in your readings or CP. Interesting enough there are other systems that you may have heard about I am sure. Glosnos is the Russian system, Galileo is a EU system (I believe mostly French driven), a Chinese system with a name that I can spell or pronounce, and even an Indian system (however this is pretty much limited to their own geographic territory). It was asked once why would these foreign governments go to all the expense when GPS has world wide coverage: well if you were any government other than the USA, would you be comfortable with a nav. system controlled and operated by the U.S. Air Force????Chris Brown"All you need in this life is ignorance and confidence; then success is sure." - Mark Twain
Sometimes when Bush 41 is in residence in Kennebunkport, maybe 30 miles from us, GPS is really off, like half mile error. I think.
Nico WalshNicholas H. Walsh P.A.Admiralty and Maritime Law; Probate Litigation; Commercial LawPhone: (207) 772-2191Fax: (207 774-3940P.O. Box 7206120 Exchange St.Portland ME 04112This message is from a law firm, and may contain information that is privileged and confidential. If you suspect you are not the intended recipient, please delete the email and call us.
Nico WalshNicholas H. Walsh P.A.Admiralty and Maritime Law; Probate Litigation; Commercial LawPhone: (207) 772-2191Fax: (207 774-3940P.O. Box 7206120 Exchange St.Portland ME 04112This message is from a law firm, and may contain information that is privileged and confidential. If you suspect you are not the intended recipient, please delete the email and call us.