DGPS Raw data recording

  • Thread starter Thread starter Indra Bisen
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I

Indra Bisen

Hi,

I'd developed applications for normal navigational GPS enabled PDAs
those output is in NMEA format. Now I am searching for some API or
SDKs to record RT raw data which is used for DGPS correction. I'd
searched on www and this group also and found a SDK (Pathfinder) from
Trimble. But I've doubt that it will be worked for Magellan Mobile
Mapper CX.

If anybody has any comments / help links on it.

regards,

Indra Bisen
 
Hi,

I am not sure what you want to do, so let me ask some questions.

First, it is easy to record raw NMEA data from a GPS receiver to a file (I
have examples that do this in my book, see below). So, is that all that you
want?

If not, second, I presume that you have a DGPS enabled receiver that you
will be outputing the data to? The GPS receivers that are in all mobile
devices that I've used are not DGPS enabled. Such receivers, commonly,
require a serial input (real-time, not from a file) from a stationary GPS
receiver that has a known LAT/LON, to provide correction data based on the
RT errors detected from a active GPS receiver. This serial data is then
sent, still in real-time, to the DGPS enabled receiver, so that its output
data stream can be corrected for the errors thus detected. This serial
connection might be hard-wired or wireless, but (again), I haven't seen any
receivers designed for mobile devices that provide this input.

Third, since you are asking this question in a CompactFramework newsgroup,
can you provide more details on the hardware that you are going to use? If
time permits, I can see if I can provide any more concrete suggestions.

One of my real concerns is that you metion "recording of DGPS data." It is
not clear to me that this would be of any practical value, since DGPS data
is designed for real-time error correction, and not for playback at some
later time.

Dick

--
Richard Grier, MVP
Hard & Software
Author of Visual Basic Programmer's Guide to Serial Communications, Fourth
Edition,
ISBN 1-890422-28-2 (391 pages, includes CD-ROM). July 2004, Revised March
2006.
See www.hardandsoftware.net for details and contact information.
 
Hi Dick,

Sorry for my unclear post.

Your 2nd assumption is right, that I would like to record gps raw
measurements such as pseudorange, (integrated) carrier phase, Doppler,
and/ or satellite navigation message data such as satellite ephemeris
parameters, satellite clock correction parameters, iono delay
parameters, to calculate (differential) position.

My GPS device is Magellan Mobile Mapper CX which is based on WinCE 5.0
and it supports the raw measurements those are essential for post
processing. However it has inbuilt gps data logging application Mobile
Mapper CX, but it not fulfill's my organization requirements because
we need some different interface, for that reason we are developing a
customized application for data collection using this device.

I'd also developed such type of application using .net compact
framework 2.0 for HP iPAQ 612c GPS PDA which is WM6 based device but
it has normal navigational GPS which not supports raw measurements.

I hope now picture is clear.

Thanks & regards,

Indra Bisen
 
OK. This is an area that I have not had any reason to explore, so I can
only offer my thoughts.

1. You, almost certainly, will have to write your own code for this. There
certainly is nothing in the CompactFramework or Windows Mobile to support
this directly.
2. There are file on
ftp://ftp.magellangps.com/Mobile%20Mapping/MobileMapper%20CX/ that may help.
Since I don't have your hardware, I really don't know how much help they may
be.
3. What I don't see on the Magellan site is a SDK for the device. I
suspect this is what you really need to use (unless you can use the export
facility that is built-in, and process the DGPS data on a separate machine).
I think you will have to contact Magellan for help with this.

Dick

--
Richard Grier, MVP
Hard & Software
Author of Visual Basic Programmer's Guide to Serial Communications, Fourth
Edition,
ISBN 1-890422-28-2 (391 pages, includes CD-ROM). July 2004, Revised March
2006.
See www.hardandsoftware.net for details and contact information.
 
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