Re: two questions about OpenGpssim

Hi si chuanyu

> I have download the OpenGPSSim Version: 0.1.0, and compiled it using
> visual 
> C++6.0
> 
> I did the several steps, I mean, ogsencdec,ogsxmit and ogsrcrv. using 
> nav-01-template-01-06.txt as input file.But after I changed the output
> of 
> ogsrcrv into ASCII(using ogsencdec), the output nav-out-01.txt has some
> mismatch with the input file nav-01-template-01-06.txt .most of the 
> mismatching occurs at the subframe 5 and 4.
> why this occur? or is it reasonable that there's some mismatch?
> 
as much as I know it is because of two reasons
1. ogsxmit adds some noise to output which you can set the amount.
2. ogsrcvr (or better to say navigation message decoder function) is not  
able to handle subframes 4,5 yet!



> I also used the 393540x36.g12 to extract the navigation data. for every
> PRN, there are many output file with different pageno of subframe 4 and
> subframe 5. in order to simulate GPS signal, which should be used as
> the 
> input file of ogsencdec and ogsxmit to generate the signal?
> 

If you mention to the input file format of ogsxmit you will find out that you 
can just have different PRN's and all the other fields of the file names should 
be the same (week number,time of week,page number , ...).
so you can choose one of the files and change the prn field to PRN and 
ogsxmit will check all the prn's with same time , page no , ...


> thanks!
> 

 I hope it helps
regards

/*
Behzad Chenaghlou
CS & Math Department
Faculty of Science
Tehran University
Iran
*/