GPS and Barometric pressure sensor recommendation please

Hi all:
I am in the process of designing a project for school. This project 
requires a GPS sensor and a barometric pressure sensor to determine 
position in space. I have not much knowledge about sensors yet but I am 
trying. I have spent several hours googling a few terms and so far I 
came up with the Garmin 18 GPS sensor, and I am still not sure which 
barometric pressure sensor I will use. These sensors have to communicate 
to a basic stamp 2pe microprocessor. My question to you guys is: do you 
know of any sensors (GPS and/or barometric) that I should research for 
this project? Or may be you could tell me from where I could scavange 
these sensors. Any help will be greatly appreciated.

Sonoman

Sonoman wrote:
> Hi all:
> I am in the process of designing a project for school. This project 
> requires a GPS sensor and a barometric pressure sensor to determine 
> position in space. I have not much knowledge about sensors yet but I am 
> trying. I have spent several hours googling a few terms and so far I 
> came up with the Garmin 18 GPS sensor, and I am still not sure which 
> barometric pressure sensor I will use. These sensors have to communicate 
> to a basic stamp 2pe microprocessor. My question to you guys is: do you 
> know of any sensors (GPS and/or barometric) that I should research for 
> this project? Or may be you could tell me from where I could scavange 
> these sensors. Any help will be greatly appreciated.
> 
> Sonoman

To make a cargo bomb, you really need only one of these variables. Why
do you want to know both?

-- 
------------------------------------------------------------
Creepy, Soulless Gigolo for President ? NOT !
---------------------------------------------
THK is one weird, weird something.

> I am in the process of designing a project for school. This project 
> requires a GPS sensor and a barometric pressure sensor to determine 

You ARE aware that GPS will give you altitude for free, right?

Lewin A.R.W. Edwards wrote:

>>I am in the process of designing a project for school. This project 
>>requires a GPS sensor and a barometric pressure sensor to determine 
> 
> 
> You ARE aware that GPS will give you altitude for free, right?

It's less accurate than position, and that's bad enough in many situations.

Paul Burke

Bryan Hackney wrote:
...
> 
> To make a cargo bomb, you really need only one of these variables. Why
> do you want to know both?
> 

It really is the end of an age of innocence. From now on do we only 
help those who use their Real Name and email address??!! - RM

Personally I haven't used any, but I heard quite positive things about
the Lassen SQ from Trimble (http://www.trimble.com/lassensq.html).
Regards and good success!
johannes

Lewin A.R.W. Edwards wrote:
>>I am in the process of designing a project for school. This project 
>>requires a GPS sensor and a barometric pressure sensor to determine 
> 
> 
> You ARE aware that GPS will give you altitude for free, right?

No, I was not aware. As far as I know it will give you longitude and 
latitude which is like the X and Y axis. That sounds very interesting 
and I will look into it. Thanks for the tip.

Paul Burke <paul@scazon.com> wrote in message news:<2n6kekFso8bfU2@uni-berlin.de>...
> Lewin A.R.W. Edwards wrote:
> 
> >>I am in the process of designing a project for school. This project 
> >>requires a GPS sensor and a barometric pressure sensor to determine 
> > 
> > 
> > You ARE aware that GPS will give you altitude for free, right?
> 
> It's less accurate than position, and that's bad enough in many situations.
> 
> Paul Burke

I use a GPS unit that has a quoted accuracy of 4 metres for 50% of the
time.  This corresponds to the true position being within a ~50 square
metre area centred on the measurement result.  If you consider that
the surface area of the earth being some 510*10^12 square metres then
localising your position to 1 part in 10^13 is not bad.

S-V

Sonoman <billgates@microsoft.com> wrote:
> Lewin A.R.W. Edwards wrote:
> >>I am in the process of designing a project for school. This project 
> >>requires a GPS sensor and a barometric pressure sensor to determine 
> > 
> > 
> > You ARE aware that GPS will give you altitude for free, right?

And, not to forget, an unbelievably accurate clock, too.  Physicists
have been known to use a GPS receiver in experiments weighing
thousands of tonnes (i.e. which are essentially impossible to move
even if you were to try rather hard) just because they wanted to know
the exact time.

> No, I was not aware. As far as I know it will give you longitude and 
> latitude which is like the X and Y axis. 

Most "consumer-grade" GPS receivers do indeed work like that.  They
don't trust themselves enough (or can't afford the increased amount of
processing) to extract altitude, too.  Instead, they use a reference
ellipsoid or terrain altitude information as a constraint to extract
the (lon/lat) position.

-- 
Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.

On Mon, 02 Aug 2004 01:27:08 -0400, Sonoman <billgates@microsoft.com> 
wrote:

> I am in the process of designing a project for school. This project 
> requires a GPS sensor and a barometric pressure sensor to determine 
> position in space.

Vaisala radiosonde might be what you are looking for.  It contains 
temperature (two of them),  humidity and barometric sensors.  RS80 variety 
also comes with 8 channel GPS transiever (it transmits Doppler shifts, so 
you'd need to figure out how to obtain the position from them).  They are 
quite cheap on ebay, around 10 quid.

The links to check:

http://www.google.co.uk/search?q=vaisala+rs80+radiosonde
http://www.zfx.de/sonde/


   Vadim