[teqc] Trimble and Binex

Groves Keith M Civ AFRL/VSBXI Keith.Groves at hanscom.af.mil
Wed May 18 14:00:29 MDT 2005


 Brian,

Our application is determining the state of the ionosphere in terms of TEC and scintillation.  While TEC monitoring does not require the fast sample rates, scintillation estimation does.  "Scintillation" refers to relatively rapid fluctuations (1-10+ Hz) in signal intensity and phase and has been identified as the most significant impact of space weather on space-based communication and navigation systems.  Interest in this phenomenon is growing rapidly as various scientific, engineering and operational communities are beginning to appreciate its importance in terms of system effects and the geophysical environment. 

We have been actively involved in scientific analyses of scintillation events and the physical mechanisms responsible for their occurrence for more than 30 years.  Dr. Valladares from Boston College proposed using your receivers to support a network of observing sites in South America specifically to study the ionospheric processes that lead to scintillation at low latitudes, and we have been anxious to determine if they are able to meet our requirements. 

The 10 Hz sampling rate of the NetRS is marginally fast enough to monitor scintillation because it provides at best a 5 Hz (Nyquist) observable.  If the actual sample rate is only 5 Hz this has a significant impact on our ability to measure scintillation. Any steps that you can take to insure at least a true 10 Hz sample rate for C/No (maintaining <=0.1 dBHz intensity resolution) would be of great interest to us.  Thank you.

					Keith Groves

-----Original Message-----
From: Brian Frohring [mailto:Brian_Frohring at Trimble.com] 
Sent: Wednesday, May 18, 2005 1:23 PM
To: charlie at radex.com
Cc: teqc support; Ben Mallen; jjohnson at ucar.edu; Groves Keith M Civ AFRL/VSBXI; Cesar Valladares
Subject: RE: [teqc] Trimble and Binex

Dear Charles,

Thanks for the detailed description with your query.  I have checked with engineering and verified that the observables are created at the higher rate, but the C/No estimate reported in BINEX is only updated at a 5 Hz rate.  Is it critical to your application to have C/No estimates at a 10 Hz rate?  If so, please describe your requirement so that the product manager, Ben Mallen, and I can review it and discuss it with our engineering group.

Thanks.

Best regards,
Brian Frohring

 

 > -----Original Message-----
 > From: Charles Carrano [mailto:charlie at radex.com]  > Sent: Wednesday, May 18, 2005 9:53 AM  > To: Brian Frohring  > Cc: teqc support; Ben Mallen; jjohnson at ucar.edu; Groves  > Keith M Civ AFRL/VSBXI; Cesar Valladares  > Subject: Re: [teqc] Trimble and Binex  >  >  > Dear Mr Frohring,  >  > Thanks again for your information regarding the NetRS Binex  > output. I managed to borrow a NetRS from a Trimble  > representative and I configured the unit to stream both the  > 0x7f-03 and 0x7f-02 subrecords at a sampling rate of 10 Hz  > for testing purposes.
 >
 > The C/No values in the 0x7f-03 records indeed have  > 0.1 dB-Hz resolution, but I think I may have identified a  > firmware problem with the way the data is logged. I  > collected several days worth of 10 Hz Binex data, and I've  > noticed that consecutive Co/N samples for the same SV and  > frequency (L1 or L2) are always identical. This would imply  > that the effective sample rate for the Co/N is only 5 Hz,  > despite the fact that 10 values per second are provided.
 >
 > I've attached a small Binex file that demonstrates this  > issue. The file begins with a 0x00 subrecord that contains  > the receiver firmware version. Unless I've made an error  > with the decoding, listed below are the 10 Hz values for the  > L1 Co/N from the 0x07-03 subrecord. I used the software,  > "binex-alpha.c," (version 0.23 dated 4 Jun 15, 2005) kindly  > provided by Jim Johnson to extract the Co/N data.
 >
 > Best regards,
 > Charles Carrano
 > Atmospheric and Environmental Research, Inc.
 >
 >
 > time= 798487200.0, svL1CNo[0]= 47.10
 > time= 798487200.1, svL1CNo[0]= 47.10
 > time= 798487200.2, svL1CNo[0]= 47.20
 > time= 798487200.3, svL1CNo[0]= 47.20
 > time= 798487200.4, svL1CNo[0]= 47.30
 > time= 798487200.5, svL1CNo[0]= 47.30
 > time= 798487200.6, svL1CNo[0]= 47.20
 > time= 798487200.7, svL1CNo[0]= 47.20
 > time= 798487200.8, svL1CNo[0]= 46.90
 > time= 798487200.9, svL1CNo[0]= 46.90
 > time= 798487201.0, svL1CNo[0]= 47.00
 > time= 798487201.1, svL1CNo[0]= 47.00
 > time= 798487201.2, svL1CNo[0]= 46.70
 > time= 798487201.3, svL1CNo[0]= 46.70
 > time= 798487201.4, svL1CNo[0]= 46.80
 > time= 798487201.5, svL1CNo[0]= 46.80
 > time= 798487201.6, svL1CNo[0]= 46.80
 > time= 798487201.7, svL1CNo[0]= 46.80
 > time= 798487201.8, svL1CNo[0]= 46.70
 > time= 798487201.9, svL1CNo[0]= 46.70
 > time= 798487202.0, svL1CNo[0]= 46.80
 > time= 798487202.1, svL1CNo[0]= 46.80
 > time= 798487202.2, svL1CNo[0]= 46.70
 > time= 798487202.3, svL1CNo[0]= 46.70
 > time= 798487202.4, svL1CNo[0]= 46.90
 > time= 798487202.5, svL1CNo[0]= 46.90
 > time= 798487202.6, svL1CNo[0]= 46.80
 > time= 798487202.7, svL1CNo[0]= 46.80
 > time= 798487202.8, svL1CNo[0]= 46.80
 > time= 798487202.9, svL1CNo[0]= 46.80
 > time= 798487203.0, svL1CNo[0]= 46.90
 > time= 798487203.1, svL1CNo[0]= 46.90
 > time= 798487203.2, svL1CNo[0]= 46.70
 > time= 798487203.3, svL1CNo[0]= 46.70
 > time= 798487203.4, svL1CNo[0]= 46.90
 > time= 798487203.5, svL1CNo[0]= 46.90
 > time= 798487203.6, svL1CNo[0]= 47.00
 > time= 798487203.7, svL1CNo[0]= 47.00
 > time= 798487203.8, svL1CNo[0]= 46.90
 > time= 798487203.9, svL1CNo[0]= 46.90
 > time= 798487204.0, svL1CNo[0]= 47.00
 > time= 798487204.1, svL1CNo[0]= 47.00
 > time= 798487204.2, svL1CNo[0]= 47.20
 > time= 798487204.3, svL1CNo[0]= 47.20
 > time= 798487204.4, svL1CNo[0]= 47.30
 > time= 798487204.5, svL1CNo[0]= 47.30
 > time= 798487204.6, svL1CNo[0]= 47.10
 > time= 798487204.7, svL1CNo[0]= 47.10
 > time= 798487204.8, svL1CNo[0]= 47.00
 > time= 798487204.9, svL1CNo[0]= 47.00
 > time= 798487205.0, svL1CNo[0]= 47.00
 > time= 798487205.1, svL1CNo[0]= 47.00
 > time= 798487205.2, svL1CNo[0]= 47.20
 > time= 798487205.3, svL1CNo[0]= 47.20
 > time= 798487205.4, svL1CNo[0]= 47.20
 > time= 798487205.5, svL1CNo[0]= 47.20
 > time= 798487205.6, svL1CNo[0]= 47.50
 > time= 798487205.7, svL1CNo[0]= 47.50
 > time= 798487205.8, svL1CNo[0]= 47.50
 > time= 798487205.9, svL1CNo[0]= 47.50
 >
 > Brian Frohring wrote:
 >
 > >Charles/Lou,
 > >
 > >Here are the answers regarding BINEX support.
 > >
 > >The 4700/5700/R7 support BINEX with 0x7f-02 format  > observables, which  > >have CNo values with 0.25 dB-Hz resolution.
 > >
 > >The NetRS supports BINEX with either 0x7f-02 or 0x7f-03 format  > >observables, the latter of which support 0.1 dB-Hz resolution.
 > >
 > >Best regards,
 > >Brian Frohring
 > >
 > >
 > >
 > > > -----Original Message-----
 > > > From: teqc-bounces at ls.unavco.org
 > > > [mailto:teqc-bounces at ls.unavco.org] On Behalf Of Lou Estey  > > > Sent: Monday, January 31, 2005 12:27 PM  > > > To: teqc support  > > > Cc: charlie at radex.com  > > > Subject: Re: [teqc] Trimble and Binex  > > >  > > >  > > > > [...] I'm surprised that the R7 doesn't support Binex,  > > > though, because  > > > > its spec sheet says that it does (at the bottom right  > on the first  > > > > page):
 > > > >
 > > > >
 > > > http://trl.trimble.com/docushare/dsweb/Get/Document-140051/Sp
 > > > ec_Sheet_
 > > > > -_R7_-_English.pdf
 > > > >
 > > > > The same is true for the R8. I'll follow up on this  > issue with the  > > > > folks at Trimble, in case it's a misprint. Do you know  > how I might  > > > > contact Mr. Frohring, or might he respond to an inquiry  > > > posted to this list?
 > > >
 > > > Maybe the R7 and R8 do support BINEX; I don't know one  > way or the  > > > other. Brian is on this list and frequently responds to specific  > > > questions regarding Trimble.
 > > >
 > > > --lou
 > > >
 > > > _______________________________________________
 > > > teqc mailing list
 > > > teqc at ls.unavco.org
 > > > http://ls.unavco.org/mailman/listinfo/teqc
 > > >
 > > >
 > >
 > >
 > >
 > >
 > >
 >
 >
 > 


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