[OpenSource_GPS] Why add 0.5 in pull_in and track parameter

[??]

Dear Sir:

 I found Open Source software is :

pull_carr_C1=(int) (1.69852*Bnpullcarr/Carrier_DCO_Delta/(4.0+5.333*Bnpullcarr/1000.0+(1.8856*Bnpullcarr/1000.0)*
  (1.8856*Bnpullcarr/1000.0))+0.5);

 pull_carr_C2=(int) (0.6369183/Carrier_DCO_Delta*(1.8856*Bnpullcarr/1000.0)*(1.8856*Bnpullcarr/1000.0)*1000.0/
  (4.0+5.333*Bnpullcarr/1000.0+(1.8856*Bnpullcarr/1000.0)*(1.8856*Bnpullcarr/1000.0))+0.5);

 pull_code_C1=(int) (10.598/Code_DCO_Delta*Bnpullcode/(4.0+5.333*Bnpullcode/1000.0+(1.8856*Bnpullcode/1000.0)*
  (1.8856*Bnpullcode/1000.0))+0.5);

 pull_code_C2=(int) (4.028/Code_DCO_Delta*(1.8856*Bnpullcode/1000.0)*(1.8856*Bnpullcode/1000.0)*1000.0/
  (4.0+5.333*Bnpullcode/1000.0+(1.8856*Bnpullcode/1000.0)*(1.8856*Bnpullcode/1000.0))+0.5);

I know C1 C2  is 
pull_carr_C1 = 1/(Ko*Kn)*8*zeta*On*Ts/(4+4*zeta*On*Ts+(On*Ts)^2);    
pull_carr_C2 = 1/(Ko*Kn)*4*(On*Ts)^2/(4+4*zeta*On*Ts+(On*Ts)^2); 

By compared, I wonder why add 0.5 to C1 and C2


----- Original Message ----- 
From: <opensource_gps-request at lists.psas.pdx.edu>
To: <opensource_gps at lists.psas.pdx.edu>
Sent: Thursday, May 08, 2008 3:00 AM
Subject: opensource_gps Digest, Vol 49, Issue 1


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>   1. osgps run under windows xp (yuguangzhan)
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> ----------------------------------------------------------------------
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> Message: 1
> Date: Wed, 7 May 2008 12:05:10 +0000 (UTC)
> From: yuguangzhan <yuguang.zhan at 163.com>
> Subject: [OpenSource_GPS] osgps run under windows xp
> To: opensource_gps at lists.psas.pdx.edu
> Message-ID: <loom.20080507T120323-538 at post.gmane.org>
> Content-Type: text/plain; charset=us-ascii
> 
> Hi, Cliff:
> 
> 
> I purchased a GPS1005  PCI bus board on year 2007 from GPS Creations. Now we 
> want to run it under windows xp.So we wonder if  the opensource_gps code can 
> run in windows xp and if there is a windows WDM driver available. 
> 
> Could you please advise how could I proceed in order to find
> such driver? Do you know anyone else who could have it available?
> 
> Sincerely,
> 
> yuguang.
> 
> 
> 
> 
> 
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