[OpenSource_GPS] About Navigation Data overflow
Clifford Kelley
cwkelley at earthlink.net
Mon May 19 19:04:59 PDT 2008
My recollection is that it is possible to get overflow when the end of a message frame is reached and during the time taken to decode the nav message means a few bits may overwrite the previous set. With the data overflow array we won't miss this data and it can be used later without any problems.
Cliff
-----Original Message-----
>From: ?? <jiangyigirl at yahoo.com.cn>
>Sent: May 15, 2008 7:24 PM
>To: opensource_gps at lists.psas.pdx.edu
>Subject: [OpenSource_GPS] About Navigation Data overflow
>
>Dear Sir:
>
> I'm a graduate student. I'm very interested in OSGPS. I found in track program ,there is software dealing with data overflow, as following
>
>if ((ic->frame_ready) && (bitnum < 16)) {
> /* Overflow */
> if (c->bit)
> set_bit (ch, (void *) &data_overflow[bitnum]);
> else
> clear_bit (ch, (void *) &data_overflow[bitnum]);
> }
> else {
> if (c->bit)
> set_bit (ch, (void *) &data_mesg[bitnum]);
> else
> clear_bit (ch, (void *) &data_mesg[bitnum]);
> }
>
>I think if there is data overflow, there will be error in navigation data. I wanna know is the condition of data overflow exist?
>
>Best Regards!
>
>Looking forward for your reply!
>----- Original Message -----
>From: <opensource_gps-request at lists.psas.pdx.edu>
>To: <opensource_gps at lists.psas.pdx.edu>
>Sent: Friday, May 16, 2008 3:00 AM
>Subject: opensource_gps Digest, Vol 49, Issue 4
>
>
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>> Today's Topics:
>>
>> 1. Re: About pull_in state Parameter (??)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Thu, 15 May 2008 17:58:40 +0800
>> From: ?? <jiangyigirl at yahoo.com.cn>
>> Subject: Re: [OpenSource_GPS] About pull_in state Parameter
>> To: <opensource_gps at lists.psas.pdx.edu>
>> Message-ID: <003501c8b672$4763d0f0$7001a8c0 at dlmu7657b7f615>
>> Content-Type: text/plain; charset="gb2312"
>>
>> Dear Sir,
>>
>> I still wonder why we choose 45 deg as the threshold ?
>>
>> And I have another question. According to what ,you decide the bandwide of the code loop and carrier loop? Did you do some simulation? Would you send me something about the simulation?
>>
>> Thanks.
>>
>> Looking forward for your reply.
>>
>> Best regards
>>
>> Yours,
>> Jiang Yi
>>
>> ----- Original Message -----
>> From: "Clifford Kelley" <cwkelley at earthlink.net>
>> To: "??" <jiangyigirl at yahoo.com.cn>
>> Sent: Tuesday, May 13, 2008 8:56 AM
>> Subject: Re: [OpenSource_GPS] About pull_in state Parameter
>>
>>
>>> The threshold for power is set at the sqrt of 2 times the rms value. To approximate this with integer values it was multiplied by 14 first and then divided by 10.
>>>
>>> 1200 was chosen as an approximate value of 45 deg based on the scaling used in the 4 quadrant arc tangent function.
>>>
>>> I hope this helps,
>>>
>>> Cliff
>>>
>>> -----Original Message-----
>>>>From: ?? <jiangyigirl at yahoo.com.cn>
>>>>Sent: May 8, 2008 7:41 PM
>>>>To: opensource_gps at lists.psas.pdx.edu
>>>>Subject: [OpenSource_GPS] About pull_in state Parameter
>>>>
>>>>Dear Sir:
>>>>
>>>> I'm a graduate student. I'm very interested in OSGPS. I wanna know the detail about OSGPS.
>>>>
>>>>In the end of pull_in state, the software use if (c->avg > 14 * rms / 10 && c->th_rms < 12000 && c->ms_set) as the condition for track state.
>>>>
>>>>My problem :
>>>>1 avg > 14 * rms / 10 ,what's the meaning of 14 and 10
>>>>2 c->th_rms < 12000 why should we choose 12000 as the the threshold
>>>>
>>>>Looking forward for your reply!
>>>>Best Regard!
>>>>
>>>>
>>>>----- Original Message -----
>>>>From: <opensource_gps-request at lists.psas.pdx.edu>
>>>>To: <opensource_gps at lists.psas.pdx.edu>
>>>>Sent: Friday, May 09, 2008 3:00 AM
>>>>Subject: opensource_gps Digest, Vol 49, Issue 2
>>>>
>>>>
>>>>> Send opensource_gps mailing list submissions to
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>>>>> or, via email, send a message with subject or body 'help' to
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>>>>>
>>>>> Today's Topics:
>>>>>
>>>>> 1. ???? (shuaihan at live.com)
>>>>> 2. Re: Why add 0.5 in pull_in and track parameter (??)
>>>>>
>>>>>
>>>>> ----------------------------------------------------------------------
>>>>>
>>>>> Message: 1
>>>>> Date: Wed, 7 May 2008 12:00:42 -0700
>>>>> From: <shuaihan at live.com>
>>>>> Subject: [OpenSource_GPS] ????
>>>>> To: opensource_gps at lists.psas.pdx.edu
>>>>> Message-ID: <BAY0-MC10-F1057EBD7F68494E7B6E0E3A2D10 at phx.gbl>
>>>>> Content-Type: text/plain; charset="us-ascii"
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>>>>> ------------------------------
>>>>>
>>>>> Message: 2
>>>>> Date: Thu, 8 May 2008 09:55:09 +0800
>>>>> From: "??" <jiangyigirl at yahoo.com.cn>
>>>>> Subject: Re: [OpenSource_GPS] Why add 0.5 in pull_in and track
>>>>> parameter
>>>>> To: <opensource_gps at lists.psas.pdx.edu>
>>>>> Message-ID: <000b01c8b0ae$8e56a420$7001a8c0 at dlmu7657b7f615>
>>>>> Content-Type: text/plain; charset="iso-8859-1"
>>>>>
>>>>> 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
>>>>>
>>>>>
>>>>>> Send opensource_gps mailing list submissions to
>>>>>> opensource_gps at lists.psas.pdx.edu
>>>>>>
>>>>>> To subscribe or unsubscribe via the World Wide Web, visit
>>>>>> http://lists.psas.pdx.edu/cgi-bin/mailman/listinfo/opensource_gps
>>>>>> or, via email, send a message with subject or body 'help' to
>>>>>> opensource_gps-request at lists.psas.pdx.edu
>>>>>>
>>>>>> You can reach the person managing the list at
>>>>>> opensource_gps-owner at lists.psas.pdx.edu
>>>>>>
>>>>>> When replying, please edit your Subject line so it is more specific
>>>>>> than "Re: Contents of opensource_gps digest..."
>>>>>>
>>>>>>
>>>>>> Today's Topics:
>>>>>>
>>>>>> 1. osgps run under windows xp (yuguangzhan)
>>>>>>
>>>>>>
>>>>>> ----------------------------------------------------------------------
>>>>>>
>>>>>> 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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>>>>>>
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