[gps-talkusers] Re: GPS suddenly changing locations?

  • From: Charles LaPierre <charles@xxxxxxxxxxxxxxxx>
  • To: gps-talkusers@xxxxxxxxxxxxx
  • Date: Tue, 25 Sep 2007 05:19:05 -0700

Hi Jim
I saw this with some other receiver we were testing, but the frequency that was happening was quite high and we decided not to use that receiver. I personally haven't see that with the 236 or with the m1000, but has heard of single instances when that has happened. I believe there is a bug in the GPS receiver firmware that causes this sudden jump in location when an unexpected error occurs. The other explanation for this could be that a bad satellite was still sending information and the emphermeris of the GPS receiver hasn't been updated yet to ignore that satellites information 

Charles.

At 07:46 PM 9/24/2007, you wrote:
Hey Charles, did you see my message and Claude's reply about being in GPS mode and suddenly it said I was some three miles south of where I really was? I had that happen once before with GPS 3.5 only that time I was about 35 miles out a sea, somewhere west of San Francisco. That was a strange feeling, kind of like being in the twilight zone! It only happened twice to me and I think Claude said he had it happen once. Any thoughts on that? Jim 
]
----- Original Message ----- From: "Charles LaPierre" <charles@xxxxxxxxxxxxxxxx> 
To: <gps-talkusers@xxxxxxxxxxxxx>
Sent: Monday, September 24, 2007 7:38 PM
Subject: [gps-talkusers] Re: Announcing Holux M1000



Hi Alex,
The fact of the matter is a more sensitive receiver will be able to pick up GPS signals more easily both direct and reflected. So you get both good and bad signals, you pickup more signals but in the process also pick up some more erroneous signals. 

Take this example:
WIth the slim 236 you get no signal inside your local shopping mall.
With the M-1000 you now get a signal but it bounces you from one end of a the building to the other. What would your prefer? I would rather have a signal even if its somewhat in error than no signal at all. 

Hope this helps.
Charles.


At 06:23 PM 9/24/2007, you wrote:
What is a multipath situation, and why is it a problem if the receiver is so much more sensitive? 

Have a great day,
Alex


----- Original Message -----
From: Chris Grabowski <chris@xxxxxxxxxxxxxxxx
To: gps-talkusers@xxxxxxxxxxxxx
Date sent: Mon, 24 Sep 2007 21:18:14 -0400
Subject: [gps-talkusers] Re: Announcing Holux M1000



Hi Alex,
We spent a number of months with the Holux M-1000.  in our tests

the

accuracy was better then the gpslim 236.
the time to first fix is much faster with the m-1000.
Usually when the m-1000 gets WAAS it keeps it.
it also worked great at slow speeds.  I'm talking around 1 mph or

0.8

mph.  the M-1000 was right on.
Now having said that, the m-1000 is a super sensitive receiver

which

could have an effect in multi path situations.
But as Mike says a place like New York city will be the true test

for

the m-1000 and multi path.   I have actually went and re recorded

some

of my user.poi's because in some situations I was able to get a

better

position.
Hope this helps.
Chris
On Mon, 24 Sep 2007 20:28:20 -0400, you wrote:



Are you saying it has better accuracy than the 236?



Have a great day,
Alex



----- Original Message -----
From: Michael May <mikemay@xxxxxxxxxxxxxxxx
To: "GPS-talkusers-freelists.org" <GPS-talkusers@xxxxxxxxxxxxx
Date sent: Mon, 24 Sep 2007 17:16:50 -0700
Subject: [gps-talkusers] Announcing Holux M1000



Sendero is constantly testing various GPS receivers.  We have

been using the Holux M1000 for several months and have now
switched from the 236 to the M1000.  We do not have the M1000
modified at all.  You can purchase it on-line for around $50 plus
shipping and tax if applicable.



We now ship the M1000 with new GPS packages.  It of course comes

with a custom case so you can easily put it on a shoulder strap.



It works fine at the pedestrian speeds, something we tested a

lot.



Its major benefit is its battery life and greater sensitivity.

It will acquire faster and pick up better among buildings or
within single story buildings.



It is almost exactly the same size as the 236.  It has a slide

switch for power and uses the same charger and battery as the
236.  The battery life seems to be about double that of the 236.



I am currently in New York to be on Good Morning America live

Tuesday morning.  This is a pretty good test bed for this new
receiver.



I believe the Sendero price is $99 for Sendero users.  Sheila

will know for sure.  I like it a lot.






Michael G.  May



CEO Sendero Group



Crashing Through by Robert Kurson now available.  Go to

http://www.CrashingThrough.com



Developers and distributors of the first-ever accessible GPS
Distributing BrailleNote, VoiceNote, Talks, Miniguide and the ID

Mate bar code reader



MikeMay@xxxxxxxxxxxxxxxx
http://www.SenderoGroup.com



1-888-757-6810, Fax (530) 757-6830, Mobile (530) 304-0007
Sendero Group, LLC
1118 Maple Lane, Davis, CA 95616-1723, USA



Latitude, 38 33 9.239 North
Longitude, 121 45 40.145 West







Charles M. La Pierre CTO
Sendero Group, LLC

Lat. 37 15' 25" N  Lon: 121 53' 04" W





Charles M. La Pierre CTO
Sendero Group, LLC

Lat. 37 15' 25" N  Lon: 121 53' 04" W

Other related posts:

  1. Home
  2. gps-talkusers
  3. Archive
  4. 09-2007