[Paddlewise] GPS and PCS

     Just a random offering on navigation and "emergency" gear.  
     
     The Federal Communications Commission has a mandate in place to 
     require wireless personal communication service (PCS) handsets --- 
     including cellular telephones --- which place 911 emergency calls to 
     be immediately locatable to within 125 meters by the 911 emergency 
     responder by the year 2001.  There is extensive effort going on 
     currently to develop Global Positioning System (GPS) chips for 
     incorporation into PCS systems to meet this requirement.  The 125 
     meter accuracy is based on requirements to be able to provide this 
     location capability in large cities as well as in open areas; large 
     cities, with a complex of large buildings serving as reflectors, 
     confuse the GPS capabilties, and introduce a new set of errors.
     
     However, using differential GPS techniques, the 911 responder, knowing 
     its own location with very high accuracy, can easily compute the 
     pseudo-random error which the commercial GPS system includes; and, 
     since it can assume that the PCS will route a 911 call to one of the 
     system's closest responding sites, it can also assume that the 911 
     caller is essentially "local", and can assign the same GPS error to 
     that user, as well.  Since GPS also provides a highly reliable time 
     stamp, the system should be able to integrate the location of the 911 
     caller to near-military accuracy --- or about five meters --- in open 
     areas covered by cellular systems.
     
     Therefore, unless you're Ralph Diaz, jumping out of a New York cab and 
     de-bagging a sak-yak to practice rolls in a flooded sinkhole in the 
     middle of Sixth Avenue, kayakers should have a new safety backup 
     system by 2001 --- assuming you're in cellular service zones, too, of 
     course.  (How this effects our kindred spirits north of the border is 
     not known --- and, obviously, it effects only those who have bat-phone 
     coverage.)  Also an unknown --- can you dial 411 to find out where you 
     are?
     
     You can paddle, but you can't hide!
     
     Jack "Joq" Martin
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