NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Timekeeping and sight time records
From: Fred Hebard
Date: 2005 Mar 17, 14:58 -0500
From: Fred Hebard
Date: 2005 Mar 17, 14:58 -0500
Victor, We're all delighted when these cans get opened! Usually, the more worms, the better. Hope you have a good trip. Fred On Mar 17, 2005, at 2:43 PM, Victor Garand wrote: > Thanks Fred. > > I apologize again for having apparently opened a can of worms with a > simple > question. Since I will be away for some time, I look forward to > rejoining > the list when I return. > > > ----- Original Message ----- > From: "Fred Hebard"> To: > Sent: Thursday, March 17, 2005 11:52 AM > Subject: Re: Timekeeping and sight time records > > >> The prospect of global shutdown of UPS is one of the few rationales >> for >> celestial nav, so don't ruin our excuses too thoroughly in the name of >> truth :). Also, GPS satellites could be targeted during war. >> >> It's important to remember the difference between GPS time and UT1, >> and >> to be careful about which time is displayed on the unit. Especially >> if >> that were switchable by the user, it could lead to errors during times >> of stress. >> >> Fred >> >> On Mar 17, 2005, at 12:52 PM, Richard Langley wrote: >> >>> 1) DoD cannot make the decision by themselves. It would have to come >>> from the >>> White House. And any such decision is highly unlikely. Even during >>> 9/11, GPS >>> was not shut down. Futhermore, with localized jamming capability, it >>> could be >>> argued that there is no real need for a global shutdown anyway. >>> 2) Use of GPS for setting a time piece that would be used as a time >>> reference >>> for celestial observations seems to me to be quite valid. >>> -- Richard Langley >>> Professor of Geodesy and Precision Navigation >>> and Contributing Editor, GPS World Magazine >>> >>> On Thu, 17 Mar 2005, Victor Garand wrote: >>> >>>> Richard, >>>> >>>> Dual use applies to many facilities but it should not be confused >>>> with dual >>>> control particularly where national defence is concerned. The bottom >>>> line, >>>> as we have all been reminded is that national security trumps ALL. >>>> >>>> In any case, it seems to me that the only legitimate introduction of >>>> GPS on >>>> this particular List is its use as a training aid (check) in >>>> developing >>>> proficiency in the area of celestial navigation. >>>> >>>> Vic >>>> >>>> >>>> ----- Original Message ----- >>>> From: "Richard Langley" >>>> To: >>>> Sent: Thursday, March 17, 2005 7:58 AM >>>> Subject: Re: Timekeeping and sight time records >>>> >>>> >>>>> On Thu, 17 Mar 2005, Victor Garand wrote: >>>>> >>>>>> By the way, if you need an excuse to spend time on the subject of >>>>>> celestial >>>>>> navigation, don't forget that the GPS network is a DoD facility. I >>>>>> understand that general access is officially at the discretion of >>>>>> DoD >>>>>> (national emergencies etc. could change the situation). >>>>> >>>>> Not correct. GPS is officially a dual-use system. See >>>>> >>>> FactSheetSPACE-BASEDPOSITIONINGNAVIGATIONTIMING.pdf>. >>>>> >>>>> -- Richard Langley >>>>> >>>>> =================================================================== >>>>> == >>>>> ========== >>>>> Richard B. Langley E-mail: lang@unb.ca >>>>> Geodetic Research Laboratory Web: >>>>> http://www.unb.ca/GGE/ >>>>> Dept. of Geodesy and Geomatics Engineering Phone: +1 506 >>>>> 453-5142 >>>>> University of New Brunswick Fax: +1 506 >>>>> 453-4943 >>>>> Fredericton, N.B., Canada E3B 5A3 >>>>> Fredericton? Where's that? See: >>>>> http://www.city.fredericton.nb.ca/ >>>>> =================================================================== >>>>> == >>>>> ========== >>>>> >>>> >>> >>> >>> ===================================================================== >>> == >>> ======== >>> Richard B. Langley E-mail: lang@unb.ca >>> Geodetic Research Laboratory Web: >>> http://www.unb.ca/GGE/ >>> Dept. of Geodesy and Geomatics Engineering Phone: +1 506 >>> 453-5142 >>> University of New Brunswick Fax: +1 506 >>> 453-4943 >>> Fredericton, N.B., Canada E3B 5A3 >>> Fredericton? Where's that? See: >>> http://www.city.fredericton.nb.ca/ >>> ===================================================================== >>> == >>> ======== >>> >> >