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Resolution of GPS integer ambiguities (N)

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geodesist
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Hello,?ÿ

Could I know, please, how to resolve (fixation) the?ÿGPS ambiguity (N)? (practically, not theoretically,?ÿPlease).

Thanks


 
Posted : November 22, 2018 7:27 am
david-livingstone
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I know enough about it to know I canƒ??t answer your question. Truth is there are very few people that know exactly how it works. ?ÿI do know that is why it takes multiple satellites to resolve it. ?ÿThere is a lot going on in a GPS receiver in terms of software to make it easy for us not to worry about it.?ÿ


 
Posted : November 22, 2018 9:42 am
paul-in-pa
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I would suggest a college level course on GPS theory and practice. We did some practical resolution but it was informative and not fun. I understand it enough to know I could not satisfy your inquiry. Good question is you seem to have a problem, but are not confident in resolving it. Please fill in some blanks.

Paul in PA


 
Posted : November 22, 2018 10:00 am
jhframe
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The goal behind the question isn't clear to me.?ÿ Are you interested in working a problem through by hand just to understand how it's done, are you trying to write software for the purpose, or do you need to derive reliable positions from an existing data set??ÿ Or something else entirely?


 
Posted : November 22, 2018 10:04 am
Mark Mayer
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Posted by: geodesist

Hello,?ÿ

Could I know, please, how to resolve (fixation) the?ÿGPS ambiguity (N)? (practically, not theoretically,?ÿPlease).

Thanks,

Practically, you use a software program written for the purpose. Like TBC or LGO, or any of many others. If running in RTK mode such calculations are done in the data collector. The details of how to collect suitable data, load it into the program,?ÿ initiate the calculations, and analyse the results would make for a very long posting indeed.?ÿ?ÿ


 
Posted : November 22, 2018 10:40 am

geeoddmike
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The LAMBDA method is described in the following links:

https://pdfs.semanticscholar.org/3801/aa69b4675a88a8958614b2ff2806727ba29b.pdf

http://www.utdallas.edu/~aiken/GPSCLASS/lambdaambigfulltext.pdf

Do a Google search for LAMBDA method for integer bias estimation for more.

As other replies note, unless you have access to software allowing you to retrieve information not available for extraction from commercial packages, I donƒ??t know how you implement your own version of an integer-fixing tool.

You might want to check the Mathworks site to see if anyone has posted a file showing how to implement the LAMBDA method. Matlab ƒ??mƒ? files are script files which can, in most cases, be modified to work with open sources software like INRIAƒ??s Scilab and others.

HTH,

DMM

P.S. Evidently the Delft University of Technology does offer access to their LAMBDA code. See:?ÿ https://www.tudelft.nl/citg/over-faculteit/afdelingen/geoscience-remote-sensing/research/research-themes/positioning-navigation-and-timing-pnt/gps/lambda-method/

?ÿ


 
Posted : November 22, 2018 12:34 pm