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Tips and questions relating to the GPS modules from SFE
By mazahirp
Hi All,

I am seeking help on certain doubts I have which will help me understand the system better. My doubts are listed below.

Lets say, I want to design a system with 2 receivers. 1st one would be my base and the 2nd as my rover. So, I would like to know:

a). How do I calculate integer ambiguity? What role will double differentiation method play in calculation of integer ambiguity?

b). I know all the errors are eliminated using the double differentiation method, but what will be the inputs and outputs of this method? Is the output the integer value 'n'? Are the inputs directly available from the GPS data?

c). I know this may sound silly, but once the integer value 'n' is calculated, what exactly is to be done with it?

d). What is ambiguity search? Is it required in the process to calculate 'n'?

d). What is baseline and how is it calculated?

e). Why is it said that close to 20 minutes of data is required for baseline calculation?

f). Where is the baseline calculated? Base station or rover?

g). What values are sent from base to rover besides its location? Is 'n' also sent? I have read that correction data is sent, so what is this correction data?

h). If double differentiation is used for ambiguity, what is the method for position estimation? What are its inputs and outputs?

i). Where is least square estimation used?

I would be really grateful and happy to get some help. I have read but all is confusing and in places.

Thank you & Regards,