GPS
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I heard on the radio that the goverment is turning off scambling on the
civilian GPS siganls at midnight tonight. They will then be up to 10 times
more accurate.
civilian GPS siganls at midnight tonight. They will then be up to 10 times
more accurate.
Comments
Original Message
From: "Mike DeMetz" <miked@t...>
To: <basicstamps@egroups.com>
Sent: Tuesday, May 02, 2000 9:01 AM
Subject: [noparse][[/noparse]basicstamps] [noparse][[/noparse]OT] GPS
> I heard on the radio that the goverment is turning off scambling on the
> civilian GPS siganls at midnight tonight. They will then be up to 10 times
> more accurate.
>
>
>
http://www.npr.org/ramfiles/atc/20000501.atc.13.ram
Regards,
Al Williams
AWC
*Measure and count 8 pulse channels:
http://www.al-williams.com/awce/pak7.htm
GPS unit to market for the PALM series - it MIGHT be something adaptable
for basic stamps (?)
--
ARC in Lago Vista, TX
Ferris: Life moves pretty fast. If you don't stop and look around once in
awhile, you could miss it.
Just the receiver and output data.· II made it interface with my stamp.
Thanks
Ralph
section at www.trimble.com .
>>> "Ralph Rogers" <fdcsouth@9...> 05/22/00 02:33PM >>>
Anyone know where to get gps receivers only, no case, display, etc.
Just the receiver and output data. II made it interface with my stamp.
Thanks
Ralph
www.digisys.net/timeline
and buy their Rockwell Jupiter GPS Engine module for $69 plus shipping. You
will need to buy a GPS Active antenna with an SMA connector on it as well. I
do not believe Timeline sells them.
Check out:
www.joemehaffey.com
for links to places to buy antennas.
Then get the Jupiter documentation at the following sites. Be sure to get
ALL the documentation.
Zodiac GPS Receiver Family Designers Guide - (142 page)
http://www.unitronic.de/rockwell/pdf/gps/Zodiac%20DG_GPS-33.pdf
Zodiac Serial Data Interface Specification - (84 page)
http://www.c2-tech.com/~steveb/ka9mva/zodiac.pdf
Manual - (18 page)
http://www.unitronic.de/rockwell/pdf/gps/gd003g.pdf
This unit WILL meet your requirements. Please READ the documentation to
understand how to hook up the Jupiter.
_____________________________________________________
Victor Fraenckel - The Windman vfraenc1@n...
Home of the WindReader Electronic Theodolite
Read the WIND
richard
Original Message
From: Victorf <vfraenc1@n...>
To: Stamp Mailing List <basicstamps@egroups.com >
Sent: Monday, May 22, 2000 5:22 PM
Subject: [noparse][[/noparse]basicstamps] Re: gps
> Go to Timeline at:
>
> www.digisys.net/timeline
>
> and buy their Rockwell Jupiter GPS Engine module for $69 plus shipping.
You
> will need to buy a GPS Active antenna with an SMA connector on it as well.
I
> do not believe Timeline sells them.
>
> Check out:
>
> www.joemehaffey.com
>
> for links to places to buy antennas.
>
> Then get the Jupiter documentation at the following sites. Be sure to get
> ALL the documentation.
>
> Zodiac GPS Receiver Family Designers Guide - (142 page)
> http://www.unitronic.de/rockwell/pdf/gps/Zodiac%20DG_GPS-33.pdf
>
> Zodiac Serial Data Interface Specification - (84 page)
> http://www.c2-tech.com/~steveb/ka9mva/zodiac.pdf
>
> Manual - (18 page)
> http://www.unitronic.de/rockwell/pdf/gps/gd003g.pdf
>
> This unit WILL meet your requirements. Please READ the documentation to
> understand how to hook up the Jupiter.
> _____________________________________________________
>
> Victor Fraenckel - The Windman vfraenc1@n...
> Home of the WindReader Electronic Theodolite
> Read the WIND
>
>
>
>
>
Microtracker.
Also, what is Timeline incs web site address.
Thanks
Ralph
http://www.digisys.net/timeline/
Also, Delorme is blowing out their 1st gen stuff at $50 per:
http://www.delorme.com/user/bargains.htm#gpstripmate
Enjoy,
Bill Mrozinski
Ralph Rogers wrote:
> Does anyone know what web site has the data sheets for the Rockwell's GPS rx
> Microtracker.
> Also, what is Timeline incs web site address.
>
> Thanks
> Ralph
form another company, they don't have info on the older units anymore.
You can get all the interfacing info you need from the August and Dec.
1995 articles in the British Electronics World Magazine. The August
article is called "Finding GPS" on page 664 and the Dec. article is
called "Interfacing the GPS Receiver", page 1066.
BTW, those old Delorme Tripmate receivers work quite well if you cut
off the 2" square pcb passive antenna and connect a 5 volt active
antenna instead.
--- In basicstamps@egroups.com, "William E. Mrozinski" <dcs@h...>
wrote:
> Here you go Ralph, you should have better luck with Timelines' GPS
boards.
>
> http://www.digisys.net/timeline/
>
> Also, Delorme is blowing out their 1st gen stuff at $50 per:
>
> http://www.delorme.com/user/bargains.htm#gpstripmate
>
> Enjoy,
> Bill Mrozinski
>
> Ralph Rogers wrote:
>
> > Does anyone know what web site has the data sheets for the
Rockwell's GPS rx
> > Microtracker.
> > Also, what is Timeline incs web site address.
> >
> > Thanks
> > Ralph
I want to add GPS to my robot, so the Stamp2XS·can log the position. What is a good and cheap GPS-receiver for this project?
With kind regards,
Rik Vlaming
40mm x 10mm, optional antenna, 12 channels, 2 serial port communications.
the etrex summit with built in barometer. Walmart
carries them at walmart.com.
Matt Klarich
__________________________________________________
Do You Yahoo!?
Yahoo! Photos - Share your holiday photos online!
http://photos.yahoo.com/
I am looking for a GPS to hook up to the BSII. All I want is GPS
receiver that will plot an XY axis to the Basic Stamp. I don't want an
interface on the GPS. Smaller the better. Does anyone know where I could get
one please.
Thanks,
Travis
_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
I have one Magellan GPS· model 315 and spent about US$·144 + taxes in the aquisition (I was travelling in Chicago area and buy it in a Best Buy store).
This model have a serial output function and I think it will be very easy to interface with· B. Stamp, using serin and serout intructions to aquire· the information you need.
More information about this GPS, including protocol, boud rate, etc, you can find in this link:
http://www.magellangps.com/frames/frame2.htm
Whats your idea whit GPS and· the Stamp?
Please forgive my bad english.
Best regards,
Luiz Augusto Baldini
São Paulo· - Brazil
Original Message
From: Travis M
To: basicstamps@yahoogroups.com
Sent: Monday, February 19, 2001 6:04 PM
Subject: [noparse][[/noparse]basicstamps] GPS
hello,
··· I am looking for a GPS to hook up to the BSII. All I want is GPS
receiver that will plot an XY axis to the Basic Stamp. I don't want an
interface on the GPS. Smaller the better. Does anyone know where I could get
one please.
······················· Thanks,
··························· Travis
_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
and were it is going? And how do I program it?
Please Help.
Paul
>
Original Message
> From: morpheus358@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=4B-RSHQilwbhScE9Det4o9-XhrExcpD0De9vYCligClE4HDYL6nSd2ZJPzDPOzAZpDG_6XcCbA7skf1hv4k]morpheus358@a...[/url
> Sent: Monday, March 12, 2001 5:50 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] GPS
>
>
> Where can i buy a GPS system that can tell a stamp robot were it is
> and were it is going? And how do I program it?
>
> Please Help.
>
>
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
so I don't want to try to tell you one is better than the other but
here are some web sites I have found.
http://www.axiomnav.com/
http://www.garmin.com/products/gps25/
For some reason it seems most people who deal with a GPS also are looking
for a compass.
I'm not sure if any of the above GPS systems have built in compass. The web
sites do not indicate.
http://www.wirz.com/products/0181/
Thanks,
Wayne Fulcher
wayne@d...
Original Message
From: morpheus358@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Mtc0A6mUsQN-OvJGfDbKgQsrF-KKnBpOO8uS9DxOrWIjnHwSB3yNtYGbGVjoB4cGxhB5cp-olRCKQXd8JA]morpheus358@a...[/url
Sent: Monday, March 12, 2001 7:50 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] GPS
Where can i buy a GPS system that can tell a stamp robot were it is
and were it is going? And how do I program it?
Please Help.
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
I went to the tapr sight and found the "interface board...kit". What exactly
is that? Is that board a gps system, or a daughter board for the Garmin 25?
Dave
--- Paul Verhage <pverhage@s...> wrote:
> Try the TAPR site, at www.tapr.org.
>
> Paul
>
> >
Original Message
> > From: morpheus358@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=tdWOkzYiblKaaw7O8PmedTD7jJE-AC0dPojzLEeurysqRHa9lqX-4nk4ypVhNyPaRhTTVKF16bhEheg]morpheus358@a...[/url
> > Sent: Monday, March 12, 2001 5:50 PM
> > To: basicstamps@yahoogroups.com
> > Subject: [noparse][[/noparse]basicstamps] GPS
> >
> >
> > Where can i buy a GPS system that can tell a stamp robot were it is
> > and were it is going? And how do I program it?
> >
> > Please Help.
> >
> >
> >
> >
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> >
> >
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
__________________________________________________
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Yahoo! Auctions - Buy the things you want at great prices.
http://auctions.yahoo.com/
Say if I am wanting to build a circuit on a breadboard, how
do you connect the pins on the GPS to the breadboard?
It appears to have the need for some sort of ribbon cable.
Thanks,
Wayne Fulcher
wayne@d...
Original Message
From: Mike Mocenter [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=ru98Ecy4nQpF3YmKG9eHb6x38hxjaaCc0cSJ3xUnuM6hnRdUKgsZbjKsNojtu6LDPseW1FQkWwEwNQ]mocenter@e...[/url
Sent: Tuesday, March 13, 2001 6:02 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] GPS
Dear Wayne,
I have the Axiom B1 module working with the stamp ands the intuitive
circuits overlay boards on 2 different projects and it works well. The code
is somewhat easy as the output is the std serial data stream that everyone
uses. Look at the Axiom site and go to gps receivers and then look at the
Swift B1 specs. It is the size of two postage stamps and acquires within 8
seconds using the "continuous" mode. The trickle modes are just o.k. as
they save power, but are a longer time to acquire. Good luck.
Mike Mocenter
mocenter@e...
www.memelectronics.com
Original Message
From: Wayne Fulcher <wayne@d...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, March 13, 2001 10:21 AM
Subject: RE: [noparse][[/noparse]basicstamps] GPS
> I have not personally bought one myself yet,
> so I don't want to try to tell you one is better than the other but
> here are some web sites I have found.
>
> http://www.axiomnav.com/
> http://www.garmin.com/products/gps25/
>
> For some reason it seems most people who deal with a GPS also are looking
> for a compass.
> I'm not sure if any of the above GPS systems have built in compass. The
web
> sites do not indicate.
>
> http://www.wirz.com/products/0181/
>
>
> Thanks,
> Wayne Fulcher
> wayne@d...
>
>
Original Message
> From: morpheus358@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=31D4qXaURoN2fW1QxTI3m7I-v5zmTiSqpxpTeg8EyZNtWj98MYc5OUMyHpg0EBpnRG1hMrqTTYM6Xg]morpheus358@a...[/url
> Sent: Monday, March 12, 2001 7:50 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] GPS
>
> Where can i buy a GPS system that can tell a stamp robot were it is
> and were it is going? And how do I program it?
>
> Please Help.
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
morning. But it sounds like it might be a RS232 and power supply board.
Paul
> Paul,
> I went to the tapr sight and found the "interface
> board...kit". What exactly
> is that? Is that board a gps system, or a daughter board for
> the Garmin 25?
> Dave
> --- Paul Verhage <pverhage@s...> wrote:
> > Try the TAPR site, at www.tapr.org.
> >
> > Paul
> >
> > >
Original Message
> > > From: morpheus358@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=6KshVQfk6wvZTOMMSVJXgiEejqYBXmFMxDh0l865W0l5TtWRV_P53ur7SuKurGKMYwjr2Pwis8YLFQ]morpheus358@a...[/url
> > > Sent: Monday, March 12, 2001 5:50 PM
> > > To: basicstamps@yahoogroups.com
> > > Subject: [noparse][[/noparse]basicstamps] GPS
> > >
> > >
> > > Where can i buy a GPS system that can tell a stamp robot
> were it is
> > > and were it is going? And how do I program it?
> > >
> > > Please Help.
> > >
> > >
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> > > http://docs.yahoo.com/info/terms/
> > >
> > >
> >
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
>
>
__________________________________________________
Do You Yahoo!?
Yahoo! Auctions - Buy the things you want at great prices.
http://auctions.yahoo.com/
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
I have the Axiom B1 module working with the stamp ands the intuitive
circuits overlay boards on 2 different projects and it works well. The code
is somewhat easy as the output is the std serial data stream that everyone
uses. Look at the Axiom site and go to gps receivers and then look at the
Swift B1 specs. It is the size of two postage stamps and acquires within 8
seconds using the "continuous" mode. The trickle modes are just o.k. as
they save power, but are a longer time to acquire. Good luck.
Mike Mocenter
mocenter@e...
www.memelectronics.com
Original Message
From: Wayne Fulcher <wayne@d...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, March 13, 2001 10:21 AM
Subject: RE: [noparse][[/noparse]basicstamps] GPS
> I have not personally bought one myself yet,
> so I don't want to try to tell you one is better than the other but
> here are some web sites I have found.
>
> http://www.axiomnav.com/
> http://www.garmin.com/products/gps25/
>
> For some reason it seems most people who deal with a GPS also are looking
> for a compass.
> I'm not sure if any of the above GPS systems have built in compass. The
web
> sites do not indicate.
>
> http://www.wirz.com/products/0181/
>
>
> Thanks,
> Wayne Fulcher
> wayne@d...
>
>
Original Message
> From: morpheus358@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=DLAWLYDtQt-4vENPxNtH2zBC8Qim3GA-z1ShAH3EhfALFiEaYySbrUTZN0dMe2WLZLDKY4-54dd9QZnMH9M]morpheus358@a...[/url
> Sent: Monday, March 12, 2001 7:50 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] GPS
>
> Where can i buy a GPS system that can tell a stamp robot were it is
> and were it is going? And how do I program it?
>
> Please Help.
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
When you order the gps module, it comes with an I/O board that takes the
20 pin Hirose ribbon cable to a 20 pin, wire-wrap type header. The pinout
is a little different, but all you need is 3.3-5 vdc, gnd, ser out and a 3
volt lithium battery for backuo. The other pins are not used. You can see
the Hirose pinout on the web site at the bottom of the spec sheet. I just
soldered wires on to the header. They also sell a board that interfaces the
unit to a pc. It has the Maxim 232 chip on board and some power regulation
as well as two led's that show power on and acquisition . the software is
called Conductor 3.0 which is a visual basic routine that has all the data
displayed from the unit so you can see it and know when the data is in. I
use SIRF demo as I can see the data lines coming down and the change from
"V" (no fixes) to the "A" mode that means a good fix. Hope this helps.
Mike Mocenter
Original Message
From: Wayne Fulcher <wayne@d...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, March 13, 2001 5:18 PM
Subject: RE: [noparse][[/noparse]basicstamps] GPS
> That was exactly what I was going to purchase.
>
> Say if I am wanting to build a circuit on a breadboard, how
> do you connect the pins on the GPS to the breadboard?
> It appears to have the need for some sort of ribbon cable.
>
> Thanks,
> Wayne Fulcher
> wayne@d...
>
>
Original Message
> From: Mike Mocenter [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=zATc1NEyBy5RVeo7T7YYO7HI__Gn_5q76pHkXHA9NChAP-KCBhDbemLqiWpPoubz1SiynAjBW2DB]mocenter@e...[/url
> Sent: Tuesday, March 13, 2001 6:02 PM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] GPS
>
> Dear Wayne,
> I have the Axiom B1 module working with the stamp ands the intuitive
> circuits overlay boards on 2 different projects and it works well. The
code
> is somewhat easy as the output is the std serial data stream that everyone
> uses. Look at the Axiom site and go to gps receivers and then look at the
> Swift B1 specs. It is the size of two postage stamps and acquires within
8
> seconds using the "continuous" mode. The trickle modes are just o.k. as
> they save power, but are a longer time to acquire. Good luck.
> Mike Mocenter
> mocenter@e...
> www.memelectronics.com
>
>
Original Message
> From: Wayne Fulcher <wayne@d...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, March 13, 2001 10:21 AM
> Subject: RE: [noparse][[/noparse]basicstamps] GPS
>
>
> > I have not personally bought one myself yet,
> > so I don't want to try to tell you one is better than the other but
> > here are some web sites I have found.
> >
> > http://www.axiomnav.com/
> > http://www.garmin.com/products/gps25/
> >
> > For some reason it seems most people who deal with a GPS also are
looking
> > for a compass.
> > I'm not sure if any of the above GPS systems have built in compass. The
> web
> > sites do not indicate.
> >
> > http://www.wirz.com/products/0181/
> >
> >
> > Thanks,
> > Wayne Fulcher
> > wayne@d...
> >
> >
Original Message
> > From: morpheus358@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=dMZK8YmalqQPTaS-MDk1kf9BpLKCc7_iIf_KtLB8fEpiY06oQ1ieoENDgQi67jW5RLYWyra1FGyreN0]morpheus358@a...[/url
> > Sent: Monday, March 12, 2001 7:50 PM
> > To: basicstamps@yahoogroups.com
> > Subject: [noparse][[/noparse]basicstamps] GPS
> >
> > Where can i buy a GPS system that can tell a stamp robot were it is
> > and were it is going? And how do I program it?
> >
> > Please Help.
> >
> >
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
> >
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
> >
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
date has been pushed back twice now.
http://www.laipac.com/msg4.htm
I have never owned one of these. I read the recent websites listed, and it
looks like I could get 1 meter accuracy in a certain mode? If I used one on
an outdoor robot, could I track to a position such as a house reliably? I
also would want to either manually or automatically program my robot to
avoid trees, rocks etc. Would this be possible?
The software would probably grey my hair some more, but..my hair is falling
out anyhow.
Does anyone else have a better idea for accurate outdoor positioning?
My goal was to have an autonomous robot that could go from pt A, to pt B and
know what obstacles were in its path ahead of time, or at least have it know
it was headed in the general direction of "B" and then I could use my IR
code to detect obstacles in between A, and B. I had thought of an onboard
compass but that only gives me a bearing, but I could be off the bearing
either side by 200 feet and the robot would not know.
The basic stamp versions are of course a necessity for myself, software wise.
Sincerely
Kerry
Admin@M...
WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
Kerry Barlow
p.o. box 21
kirkwood ny
13795
about 10 feet or so -- sometimes more -- usually less. You are at the mercy
of the military as far as the accuracy -- it depends on whether they tell
the satellites to intentionally transmit errors or not.
Original Message
> Hi Everyone: What sort of location accuracy can be expected from a GPS
unit?
> I have never owned one of these. I read the recent websites listed, and it
> looks like I could get 1 meter accuracy in a certain mode? If I used one
on
> an outdoor robot, could I track to a position such as a house reliably? I
> also would want to either manually or automatically program my robot to
> avoid trees, rocks etc. Would this be possible?
Actually the accuracy is dependent on the number of satellites that are viewable in the sky and the atmospheric conditions.· Certain atmospheric conditions affect the signal and degrade the accuracy.· One of the things that Clinton did was to sign a law that made the military turn off any intentional error.· This happened last year.· That was called Selective Availability.· Selective Availability was an intentional random error introduced into the signals by the military to degrade the accuracy intentionally.· They were afraid that spies, terrorist, and other bad people would use it for evil.· That is gone now, and the accuracy is quoted at 10-20 meters I think.
Here is a reprint of the article about S/A being turned off: http://www.trimble.com/home/accuracy.htm
There are techniques to improve the accuracy significantly however.· A popular technique is called differential GPS.· Basically a robot would have it's own GPS onboard.· There would also be a GPS mounted on the building or somewhere on the ground, stationary.· The postion report from the stationary GPS is compared to it's actual location.· This allows the current errors in the signals to be detected and calculated.· By comparing the actual position of the unit to the reported postion, you can very accurately calculate the errors in the signal.· Once you have this error, the amount of error in the signal is then sent to the robot via radio and it is used to calibrate it's GPS position report.· This is called DGPS.· This technique can improve the accuracy of GPS to less than a centimeter.· A GPS with a differential GPS receiver can provide extremely accurate positions.· However, it depends on the availability of a DGPS signal in your area.· These signals are provided by transmitters run by the government.· I don't know how you determine the coverage in your area.
Look at this web site for an example of a DGPS receiver:
http://www.trimble.com/products/catalog/agri/ag214.htm
This unit is designed for farmers to put on their tractors and get centimeter level accuracy for farming applications.· I'm sure it would work on a robot.· It probably costs thousands of dollars.
Another DGPS receiver is at: http://www.trimble.com/products/catalog/gis/pro_xrs.htm
You can usually buy external differential GPS receivers for any existing GPS, especially if they are intended for Marine usage.· They are ussually kind of expensive and bulky though, between $1000-$2000.· Check the web site of the manufacturer of your GPS, they may have one available.· If you have a magellan gps, they offer a DGPS reciever that will plug into· many of their handheld GPS units.· It is at:
http://www.magellangps.com/frames/frame2.htm· They claim accuracy to 3 meters with this unit.· I'd call them for more details and see if this unit is helpful.· This unit was originally designed to overcome the errors introduced with S/A and may not be accurate enough to improve the non S/A signals.
Another approach is to create your own differential GPS transmitter that sends out a correction signal.· You would have to mount a GPS somewhere on your building as a permanent installation.· You can determine its actual position by averaging the position reports it provides over a period of time, like a week or so.
Once you have it's actual position, you can determine the difference between the position report that is received by the unit and the known position.· This becomes your error correction.· You then send that to your robot via radio or any other communications method and use this correction to subtract/add from the position report to get good accuracy.· The level of accuracy that you obtain will depend on many factors, but I read an article about a guy who made a R/C airplane land and take off based on a GPS signal that was processed in this way.· He claimed to acheive 1/2 centimeter accuracy.· He got really extreme with it though and incorporated the corrections into the firmware of the GPS.
An obvious disadvantage is that you have to have a communications link between the stationary GPS and the robot.· You also have to be careful about the time factor between sending a correction report and using it.· The time the correction was calculated needs to be sent with the correction and then applied to a position report on the robot that was taken at or VERY near the same time.· I would think you could get 12 centimeter accuracy pretty easy this way with a couple of inexpensive GPS units.· It will be a function of how robust the software you build is.
Look at this web site for more info on carrier differential GPS:
http://einstein.stanford.edu/cgi-bin/people_test/data/show_person.pl?Paul=Montgomery
There is a thesis on his web site that discusses in extreme detail Carrier Differential GPS.· Unfortunately it is only in PostScript format, but you can use Paintshop pro, or Ghostscript to view/print it.
Check out the trimble web site.· They have lots of information on GPS products and accuracy.· They even have one unit that uses multiple attenaes to determine the pitch/roll/bank angle of a vehicle based on the differences between the positions of the 3 or 4 antennaes mounted on the ends of the wings and tail.
http://www.trimble.com
Original Message
From: Rodent [noparse]/noparse][url=mailto:daweasel@swbell.net]mailto:daweasel@swbell.net[/url
Sent: Wednesday, March 14, 2001 8:57 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Re: GPS
From what I have seen with vehicle-mounted GPS systems, the accuracy is
about 10 feet or so -- sometimes more -- usually less. You are at the mercy
of the military as far as the accuracy -- it depends on whether they tell
the satellites to intentionally transmit errors or not.
Original Message
> Hi Everyone: What sort of location accuracy can be expected from a GPS
unit?
> I have never owned one of these. I read the recent websites listed, and it
> looks like I could get 1 meter accuracy in a certain mode? If I used one
on
> an outdoor robot, could I track to a position such as a house reliably? I
> also would want to either manually or automatically program my robot to
> avoid trees, rocks etc. Would this be possible?
·
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
we
use to set and check our positioning equipment. It is supposed to be exactly
where
it says it is. My gps averaged 9 foot from where it was supposed to be . They
are
accurate enough to find a spot but not accurate enough for position fixing for a
robot unless you are looking for a general position.
Kerry Barlow wrote:
> Hi Everyone: What sort of location accuracy can be expected from a GPS unit?
> I have never owned one of these. I read the recent websites listed, and it
> looks like I could get 1 meter accuracy in a certain mode? If I used one on
> an outdoor robot, could I track to a position such as a house reliably? I
> also would want to either manually or automatically program my robot to
> avoid trees, rocks etc. Would this be possible?
> The software would probably grey my hair some more, but..my hair is falling
> out anyhow.
> Does anyone else have a better idea for accurate outdoor positioning?
> My goal was to have an autonomous robot that could go from pt A, to pt B and
> know what obstacles were in its path ahead of time, or at least have it know
> it was headed in the general direction of "B" and then I could use my IR
> code to detect obstacles in between A, and B. I had thought of an onboard
> compass but that only gives me a bearing, but I could be off the bearing
> either side by 200 feet and the robot would not know.
> The basic stamp versions are of course a necessity for myself, software wise.
>
> Sincerely
> Kerry
> Admin@M...
> WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
> Kerry Barlow
> p.o. box 21
> kirkwood ny
> 13795
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
The normal accuracy (without SA which was turned off just a while ago) is 20
meters horizontally (worse vertically). However, that makes lots of
assumptions that aren't true on low end (and even in some cases, high end
GPS equipment).
Civilian gear uses the L1-C/A signal only. So you essentially get a psuedo
range from 4 satellites. Because of clock imperfections, these 4 lines from
the satellites will not converge at a single point, so the receiver adjusts
its clock until the 4 points converge (this is why you can get an accurate
time signal off of GPS).
Trimble quotes the following figures:
Sat clock error - 2 ft.
Ephemeris error - 2 ft.
Receiver error - 4 ft.
Atmospheric - 12 ft.
S.A. - 25 ft (this has been turned off, though)
So without SA, the square root of the sum of the squares is around 13
ft.Then you have to multiply by PDOP (position dilution of precision -- no,
I don't understand that number) which ranges from 4 to 6, so you get about
60' best case.
Averaging over a long time can improve accuracy (assuming you aren't
moving). Long time means sample >15 minutes apart.
DGPS (differential GPS) compares the incoming position with a fixed known
receiver to reduce error considerably.
Read: http://vancouver-webpages.com/peter/gpsfaq.txt
Regards,
Al Williams
AWC
* Spring break special: http://www.al-williams.com/awce
P.S. Hey Scott, any of the old gang still around? I still talk to k5gy once
in a while (in CA, though). Haven't heard from FAZ or many of the rest for
years.
>
Original Message
> From: Scott Tappan Contractor [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=_2WuQl5XPEOFABrqwzT4Znk-bdBIuFjH55NXTSpRpRkbhsRrqz5iS1pNY30_TvGsdOCwF6v7tlMDTmc93hlDBEF8cpiwkRp5SBY]scott.tappan.contractor@n...[/url
> Sent: Wednesday, March 14, 2001 12:46 PM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] Re: GPS
>
>
> I took my 12 channel Garmin out to work where we have a
> Geological marker which we
> use to set and check our positioning equipment. It is supposed to
> be exactly where
> it says it is. My gps averaged 9 foot from where it was supposed
> to be . They are
> accurate enough to find a spot but not accurate enough for
> position fixing for a
> robot unless you are looking for a general position.
>
> Kerry Barlow wrote:
>
> > Hi Everyone: What sort of location accuracy can be expected
> from a GPS unit?
> > I have never owned one of these. I read the recent websites
> listed, and it
> > looks like I could get 1 meter accuracy in a certain mode? If I
> used one on
> > an outdoor robot, could I track to a position such as a house
> reliably? I
> > also would want to either manually or automatically program my robot to
> > avoid trees, rocks etc. Would this be possible?
> > The software would probably grey my hair some more, but..my
> hair is falling
> > out anyhow.
> > Does anyone else have a better idea for accurate outdoor positioning?
> > My goal was to have an autonomous robot that could go from pt
> A, to pt B and
> > know what obstacles were in its path ahead of time, or at least
> have it know
> > it was headed in the general direction of "B" and then I could use my IR
> > code to detect obstacles in between A, and B. I had thought of
> an onboard
> > compass but that only gives me a bearing, but I could be off the bearing
> > either side by 200 feet and the robot would not know.
> > The basic stamp versions are of course a necessity for myself,
> software wise.
> >
> > Sincerely
> > Kerry
> > Admin@M...
> > WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
> > Kerry Barlow
> > p.o. box 21
> > kirkwood ny
> > 13795
> >
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> accuracy is
> about 10 feet or so -- sometimes more -- usually less. You
> are at the mercy
> of the military as far as the accuracy -- it depends on
> whether they tell
> the satellites to intentionally transmit errors or not.
Selective Availability (SA) has been turned off. This has reduced errors to
a fraction of what they use to be. The errors now are more of a problem
with the ionosphere. When I watch my GPS data, I see the elevation jump
around a few feet. Accuracy, in my experience, is within 100 feet.
Paul