[gps-talkusers] Re: Directionality of the POI, A Compass Question

Hi Carl and everyone,
I have used the Talking Compass (which I found to be too general in terms of 
heading information) and the braille one from Brunton, the Silva distributor in 
the U.S. I have had troubles with the braille compass;the ones I have used  
broke easily and the locking mechanism on the wheel seems to be pretty fragile. 
Do you have any other options that you like or any thoughts about the Brunton? 
I don't mean to put down specific brands; I would just love to find a compass 
that is durable and that gives the detailed info that the Brunton does. Are 
there any gyroscope-based compasses that are accessible? How about compasses 
that blind sailors use?
  Thanks.
  Terrie
  ----- Original Message ----- 
  From: Carl Simmons 
  To: gps-talkusers@xxxxxxxxxxxxx 
  Sent: Friday, May 12, 2006 12:25 AM
  Subject: [gps-talkusers] Re: irectionality of the POI


  Kevin,
  One of the most important areas of providing guidance with any GPS system
  is that a correct heading must be established.  Just as when giving
  directions to a person the first piece of information would be what
  direction is the person facing.  The GPS system has to determine the heading
  by plotting your travels over a period of time. This is one of the most
  complex areas of any GPS system.

  To help understand the complexity I will try to explain the basics.  The GPS
  system will know your current position by having your location by latitude
  and longitude.  The accuracy on this point is dependent on the current GPS
  signal strength. Then after a period of time the system will again determine
  your position.  With these two points a direction of travel can be
  established.  Now enters the complexity.  Take a case that you did not move
  over this period of time, but the GPS signal accuracy varies.  This will
  change your position and now a direction of travel is determined with out
  your moving.  This is just one of the variables one must consider when
  establishing a heading direction.  
    
  As you can understand the GPS system can not provide accurate guidance until
  a correct heading has been established. This is the main rule of trusting
  the guidance is to assure that the heading is correct.  For example if you
  know you are traveling North and the GPS heading indicates east any guidance
  information could be incorrect.  One method I use is to check my heading
  with a compass and compare with the GPS heading.  One other method is to
  inquire the heading direction and travel a distance and check again then
  again.  When the heading remains the same you can figure this heading is
  correct. 

  I know this is a lengthy lesson but a very important item in understanding
  the methods used to provide guidance.  I hope this helps.
    

  Carl Simmons
  Sendero Group Training and Technical Support
  1-888-757-6810 Ext. 106
  carl@xxxxxxxxxxxxxxxx



  -----Original Message-----
  From: gps-talkusers-bounce@xxxxxxxxxxxxx
  [mailto:gps-talkusers-bounce@xxxxxxxxxxxxx] On Behalf Of Kevin Chao
  Sent: Thursday, May 11, 2006 7:30 PM
  To: Gps List
  Subject: [gps-talkusers] irectionality of the POI

  Dear List,

  I have a question regarding the directionality of the POI's.  I 
  have noticed with both commercial POI's and person POI's, for 
  some reason I am getting a off-readings, for example, it will say 
  "Mc Donald's 9 o'clock," when it is really 3 o'clock; I have 
  experienced this with both the commercial POI's and the one's I 
  marked myself, so I am not sure where the issue lies.

  I am currently using version 3.3, so I don't know if this is a 
  fix that was introduced in version 3.5, if it is I am looking 
  forward to it.

  Thank you for the information you are able to provide regarding 
  my query.
  Kevin




  -- 
  No virus found in this incoming message.
  Checked by AVG Free Edition.
  Version: 7.1.392 / Virus Database: 268.5.6/336 - Release Date: 5/10/2006

Other related posts: