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DC

David C. Partridge

Fri, Mar 31, 2017 4:17 PM

links [2] and [3] give 404 errors

Dave

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Attila Kinali
Sent: 31 March 2017 12:35
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS first LO need to be locked?

[2] "A Prototyping Platform for Multi-Frequency GNSS Receivers", by Akos, Ene and Thor, 2003 http://waas.stanford.edu/~wwu/papers/gps/PDF/AkosIONGPS033FreqRX.pdf

[3] "Design of a GPS and Galileo Multi-Frequency Front-End", by Parada, Chastellain, Botteron, Tawk, Farine, 2009 http://202.194.20.8/proc/VTC09Spring/DATA/04-04-01.PDF

links [2] and [3] give 404 errors Dave -----Original Message----- From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Attila Kinali Sent: 31 March 2017 12:35 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS first LO need to be locked? [2] "A Prototyping Platform for Multi-Frequency GNSS Receivers", by Akos, Ene and Thor, 2003 http://waas.stanford.edu/~wwu/papers/gps/PDF/AkosIONGPS033FreqRX.pdf [3] "Design of a GPS and Galileo Multi-Frequency Front-End", by Parada, Chastellain, Botteron, Tawk, Farine, 2009 http://202.194.20.8/proc/VTC09Spring/DATA/04-04-01.PDF

J

jimlux

Fri, Mar 31, 2017 4:26 PM

On 3/31/17 4:35 AM, Attila Kinali wrote:

On Thu, 30 Mar 2017 20:00:31 -0700
Peter Monta pmonta@gmail.com wrote:

BTW a lot of GPS receivers don't have a "first LO".. they are more like a

Tuned RF receiver - an input BPF for L1, L2, or L5, then direct sampling at
around 30-40 MHz - something that makes the GPS signals alias down
somewhere convenient (and always have positive frequency offset from zero,
even at max negative Doppler)

True. I've been wanting to try this with an FPGA transceiver; even the
cheap ones go to 6 Gb/s now, but binary only. The newest transceivers
support PAM-4, which would be great, but they're not affordable yet. Also
that's a lot of gain at one frequency.

I guess you know of [1] already?

Alternatively, instead of using a MAX2021, you can use a discrete
mixer and use the high analog bandwidth of todays ADCs to use them
as downmixers. [2] and [3] describe how to do this in detail.

The epitome of this is using direct sampling of the signals without
previous downmixing (e.g. [4]). Though I have no idea how easy or hard that
is with todays electronics. It will definitely need good preselection
filters to keep SNR high.

Our space GPS receiver flying on SCaN Testbed/ISS is a direct sampling
at 38 MHz. Filters are nothing special as I recall. A chain of
amplifiers with filters - Lots of gain into the thresholders, so good
layout is important.

https://trs.jpl.nasa.gov/handle/2014/41781

https://trs.jpl.nasa.gov/bitstream/handle/2014/41781/11-0046.pdf?sequence=1&isAllowed=y

		Attila Kinali

[1] http://www.aholme.co.uk/GPS/Main.htm

[2] "A Prototyping Platform for Multi-Frequency GNSS Receivers",
by Akos, Ene and Thor, 2003
http://waas.stanford.edu/~wwu/papers/gps/PDF/AkosIONGPS033FreqRX.pdf

[3] "Design of a GPS and Galileo Multi-Frequency Front-End",
by Parada, Chastellain, Botteron, Tawk, Farine, 2009
http://202.194.20.8/proc/VTC09Spring/DATA/04-04-01.PDF

[4] "Design and Implementation of a Direct Digitization GPS Receiver Front End",
by Akos, and Tsui, 1996

On 3/31/17 4:35 AM, Attila Kinali wrote: > On Thu, 30 Mar 2017 20:00:31 -0700 > Peter Monta <pmonta@gmail.com> wrote: > >>> BTW a lot of GPS receivers don't have a "first LO".. they are more like a >>>> Tuned RF receiver - an input BPF for L1, L2, or L5, then direct sampling at >>>> around 30-40 MHz - something that makes the GPS signals alias down >>>> somewhere convenient (and always have positive frequency offset from zero, >>>> even at max negative Doppler) >>> >>> >> True. I've been wanting to try this with an FPGA transceiver; even the >> cheap ones go to 6 Gb/s now, but binary only. The newest transceivers >> support PAM-4, which would be great, but they're not affordable yet. Also >> that's a lot of gain at one frequency. > > I guess you know of [1] already? > > Alternatively, instead of using a MAX2021, you can use a discrete > mixer and use the high analog bandwidth of todays ADCs to use them > as downmixers. [2] and [3] describe how to do this in detail. > > The epitome of this is using direct sampling of the signals without > previous downmixing (e.g. [4]). Though I have no idea how easy or hard that > is with todays electronics. It will definitely need good preselection > filters to keep SNR high. > Our space GPS receiver flying on SCaN Testbed/ISS is a direct sampling at 38 MHz. Filters are nothing special as I recall. A chain of amplifiers with filters - Lots of gain into the thresholders, so good layout is important. https://trs.jpl.nasa.gov/handle/2014/41781 https://trs.jpl.nasa.gov/bitstream/handle/2014/41781/11-0046.pdf?sequence=1&isAllowed=y > Attila Kinali > > [1] http://www.aholme.co.uk/GPS/Main.htm > > [2] "A Prototyping Platform for Multi-Frequency GNSS Receivers", > by Akos, Ene and Thor, 2003 > http://waas.stanford.edu/~wwu/papers/gps/PDF/AkosIONGPS033FreqRX.pdf > > [3] "Design of a GPS and Galileo Multi-Frequency Front-End", > by Parada, Chastellain, Botteron, Tawk, Farine, 2009 > http://202.194.20.8/proc/VTC09Spring/DATA/04-04-01.PDF > > [4] "Design and Implementation of a Direct Digitization GPS Receiver Front End", > by Akos, and Tsui, 1996 >

MD

Magnus Danielson

Fri, Mar 31, 2017 7:04 PM

Hi,

On 03/30/2017 03:46 PM, paul swed wrote:

I am curious if the first local oscillator on a GPS receiver must actually
be locked or coherent to the reference oscillator in the GPS receiver
typically running at some 10 MHz approximately. Or as long as the first LO
is quite stable it doesn't matter because the receiver can track the code.
This is a question for very classic receivers like Austrons, Odetics etc.
Discreet. Modern fully integrated receivers are not in question.
Thank you for your insights.

If you only do a code receiver, you can do this, but the carrier
tracking will need to compensate the LO. This is naturally possible, but
some of the precision will be lost. You can play some tricks to average
this from the channels and sort things out.

If you want to do a carrier phase receiver, you would suffer too much,
then you would need to lock the LO to get the gain.

For old receivers, I'd just assume the LO is locked, as it saves
compensation tricks later, which would save computation cycles.
However, there where some crude receivers back in the days.

Cheers,
Magnus

Hi, On 03/30/2017 03:46 PM, paul swed wrote: > I am curious if the first local oscillator on a GPS receiver must actually > be locked or coherent to the reference oscillator in the GPS receiver > typically running at some 10 MHz approximately. Or as long as the first LO > is quite stable it doesn't matter because the receiver can track the code. > This is a question for very classic receivers like Austrons, Odetics etc. > Discreet. Modern fully integrated receivers are not in question. > Thank you for your insights. If you only do a code receiver, you can do this, but the carrier tracking will need to compensate the LO. This is naturally possible, but some of the precision will be lost. You can play some tricks to average this from the channels and sort things out. If you want to do a carrier phase receiver, you would suffer too much, then you would need to lock the LO to get the gain. For old receivers, I'd just assume the LO is locked, as it saves compensation tricks later, which would save computation cycles. However, there where some crude receivers back in the days. Cheers, Magnus

MD

Magnus Danielson

Fri, Mar 31, 2017 7:19 PM

Hi Jim,

On 03/31/2017 01:07 AM, jimlux wrote:

BTW a lot of GPS receivers don't have a "first LO".. they are more like
a Tuned RF receiver - an input BPF for L1, L2, or L5, then direct
sampling at around 30-40 MHz - something that makes the GPS signals
alias down somewhere convenient (and always have positive frequency
offset from zero, even at max negative Doppler)

Still fills the function of LO, as the sample and hold operates as a
mixer and the fold-down can be seen as an overtone mix followed by a
sampling of the mix product, so well, it's about the same thing.

Cheers,
Magnus

Hi Jim, On 03/31/2017 01:07 AM, jimlux wrote: > BTW a lot of GPS receivers don't have a "first LO".. they are more like > a Tuned RF receiver - an input BPF for L1, L2, or L5, then direct > sampling at around 30-40 MHz - something that makes the GPS signals > alias down somewhere convenient (and always have positive frequency > offset from zero, even at max negative Doppler) Still fills the function of LO, as the sample and hold operates as a mixer and the fold-down can be seen as an overtone mix followed by a sampling of the mix product, so well, it's about the same thing. Cheers, Magnus

AK

Attila Kinali

Fri, Mar 31, 2017 9:29 PM

God kväll Magnus,

On Fri, 31 Mar 2017 21:19:00 +0200
Magnus Danielson magnus@rubidium.dyndns.org wrote:

Still fills the function of LO, as the sample and hold operates as a
mixer and the fold-down can be seen as an overtone mix followed by a
sampling of the mix product, so well, it's about the same thing.

"Harmonic mixer" is the word you are looking for :-)

		Attila Kinali

--
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering. -- The Doctor

God kväll Magnus, On Fri, 31 Mar 2017 21:19:00 +0200 Magnus Danielson <magnus@rubidium.dyndns.org> wrote: > Still fills the function of LO, as the sample and hold operates as a > mixer and the fold-down can be seen as an overtone mix followed by a > sampling of the mix product, so well, it's about the same thing. "Harmonic mixer" is the word you are looking for :-) Attila Kinali -- You know, the very powerful and the very stupid have one thing in common. They don't alters their views to fit the facts, they alter the facts to fit the views, which can be uncomfortable if you happen to be one of the facts that needs altering. -- The Doctor

MD

Magnus Danielson

Fri, Mar 31, 2017 10:08 PM

God natt Attila,

On 03/31/2017 11:29 PM, Attila Kinali wrote:

God kväll Magnus,

On Fri, 31 Mar 2017 21:19:00 +0200
Magnus Danielson magnus@rubidium.dyndns.org wrote:

Still fills the function of LO, as the sample and hold operates as a
mixer and the fold-down can be seen as an overtone mix followed by a
sampling of the mix product, so well, it's about the same thing.

"Harmonic mixer" is the word you are looking for :-)

Not necessarily. It could be a locked oscillator too.
Harmonic mixer is another way to go.

Cheers,
Magnus

God natt Attila, On 03/31/2017 11:29 PM, Attila Kinali wrote: > God kväll Magnus, > > On Fri, 31 Mar 2017 21:19:00 +0200 > Magnus Danielson <magnus@rubidium.dyndns.org> wrote: > >> Still fills the function of LO, as the sample and hold operates as a >> mixer and the fold-down can be seen as an overtone mix followed by a >> sampling of the mix product, so well, it's about the same thing. > > "Harmonic mixer" is the word you are looking for :-) Not necessarily. It could be a locked oscillator too. Harmonic mixer is another way to go. Cheers, Magnus

BK

Bob kb8tq

Fri, Mar 31, 2017 11:47 PM

Hi

There are a lot of GPS chips that do an I/Q mix down to a low IF. It’s then (re) sampled from there. The “LO” in this case would down convert to the low IF ….

Bob

On Mar 31, 2017, at 6:08 PM, Magnus Danielson magnus@rubidium.dyndns.org wrote:

God natt Attila,

On 03/31/2017 11:29 PM, Attila Kinali wrote:

God kväll Magnus,

On Fri, 31 Mar 2017 21:19:00 +0200
Magnus Danielson magnus@rubidium.dyndns.org wrote:

Still fills the function of LO, as the sample and hold operates as a
mixer and the fold-down can be seen as an overtone mix followed by a
sampling of the mix product, so well, it's about the same thing.

"Harmonic mixer" is the word you are looking for :-)

Not necessarily. It could be a locked oscillator too.
Harmonic mixer is another way to go.

Cheers,
Magnus

time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Hi There are a lot of GPS chips that do an I/Q mix down to a low IF. It’s then (re) sampled from there. The “LO” in this case would down convert to the low IF …. Bob > On Mar 31, 2017, at 6:08 PM, Magnus Danielson <magnus@rubidium.dyndns.org> wrote: > > God natt Attila, > > On 03/31/2017 11:29 PM, Attila Kinali wrote: >> God kväll Magnus, >> >> On Fri, 31 Mar 2017 21:19:00 +0200 >> Magnus Danielson <magnus@rubidium.dyndns.org> wrote: >> >>> Still fills the function of LO, as the sample and hold operates as a >>> mixer and the fold-down can be seen as an overtone mix followed by a >>> sampling of the mix product, so well, it's about the same thing. >> >> "Harmonic mixer" is the word you are looking for :-) > > Not necessarily. It could be a locked oscillator too. > Harmonic mixer is another way to go. > > Cheers, > Magnus > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

PS

paul swed

Sat, Apr 1, 2017 3:18 PM

Thanks everyone but I am working on an austron 2201a so all the discussions
on modern methods won't help. Whats is interesting is indeed the 2201 down
converts to 80KHz and the does sample in an IQ fashion. Its all discreet
chips and such.
Easily traceable and logical.
I think I have what I asked for and am experimenting with active mixers and
IFs made of minicircuit gain stages.
I am using a commercial antenna with 34 db of gain. It says 50db I question
that.
But lots of gain to a HP IAM 81008 active mixer low drive LO. Then a 40db
at least 75 MHz IF. (Pretty sure this is overkill.)
The LO is a HP 8660c for now. Locked to a TBolt.
Thats the reason for the question. I can shift the 8660 to the ausytron 10
MHz.
Regards
Paul.
WB8TSL

On Fri, Mar 31, 2017 at 7:47 PM, Bob kb8tq kb8tq@n1k.org wrote:

Hi

There are a lot of GPS chips that do an I/Q mix down to a low IF. It’s
then (re) sampled from there. The “LO” in this case would down convert to
the low IF ….

Bob

On Mar 31, 2017, at 6:08 PM, Magnus Danielson <

magnus@rubidium.dyndns.org> wrote:

God natt Attila,

On 03/31/2017 11:29 PM, Attila Kinali wrote:

God kväll Magnus,

On Fri, 31 Mar 2017 21:19:00 +0200
Magnus Danielson magnus@rubidium.dyndns.org wrote:

Still fills the function of LO, as the sample and hold operates as a
mixer and the fold-down can be seen as an overtone mix followed by a
sampling of the mix product, so well, it's about the same thing.

"Harmonic mixer" is the word you are looking for :-)

Not necessarily. It could be a locked oscillator too.
Harmonic mixer is another way to go.

Cheers,
Magnus

time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/

mailman/listinfo/time-nuts

and follow the instructions there.

time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.

Thanks everyone but I am working on an austron 2201a so all the discussions on modern methods won't help. Whats is interesting is indeed the 2201 down converts to 80KHz and the does sample in an IQ fashion. Its all discreet chips and such. Easily traceable and logical. I think I have what I asked for and am experimenting with active mixers and IFs made of minicircuit gain stages. I am using a commercial antenna with 34 db of gain. It says 50db I question that. But lots of gain to a HP IAM 81008 active mixer low drive LO. Then a 40db at least 75 MHz IF. (Pretty sure this is overkill.) The LO is a HP 8660c for now. Locked to a TBolt. Thats the reason for the question. I can shift the 8660 to the ausytron 10 MHz. Regards Paul. WB8TSL On Fri, Mar 31, 2017 at 7:47 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > Hi > > > There are a lot of GPS chips that do an I/Q mix down to a low IF. It’s > then (re) sampled from there. The “LO” in this case would down convert to > the low IF …. > > Bob > > > On Mar 31, 2017, at 6:08 PM, Magnus Danielson < > magnus@rubidium.dyndns.org> wrote: > > > > God natt Attila, > > > > On 03/31/2017 11:29 PM, Attila Kinali wrote: > >> God kväll Magnus, > >> > >> On Fri, 31 Mar 2017 21:19:00 +0200 > >> Magnus Danielson <magnus@rubidium.dyndns.org> wrote: > >> > >>> Still fills the function of LO, as the sample and hold operates as a > >>> mixer and the fold-down can be seen as an overtone mix followed by a > >>> sampling of the mix product, so well, it's about the same thing. > >> > >> "Harmonic mixer" is the word you are looking for :-) > > > > Not necessarily. It could be a locked oscillator too. > > Harmonic mixer is another way to go. > > > > Cheers, > > Magnus > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. >

BC

Bob Camp

Sat, Apr 1, 2017 5:23 PM

Hi

On Apr 1, 2017, at 11:18 AM, paul swed paulswedb@gmail.com wrote:

Thanks everyone but I am working on an austron 2201a so all the discussions
on modern methods won't help. Whats is interesting is indeed the 2201 down
converts to 80KHz and the does sample in an IQ fashion. Its all discreet
chips and such.

If you have a free running VCO in the head end, then indeed you need to lock it to
something. An unlocked VCO will not be close enough to frequency to do you any good.
The 8660 may or may not be close enough in free run mode. It depends a lot on
what standard you have in yours.

Easily traceable and logical.
I think I have what I asked for and am experimenting with active mixers and
IFs made of minicircuit gain stages.
I am using a commercial antenna with 34 db of gain. It says 50db I question
that.

That is a very normal antenna gain spec and it was quite common in the era the
device you have was designed. I run a number of GPS gizmos that need a 50
db antenna on them. They might work with a 40 db setup. They do not work
with something in the 20 to 30 db range. If you watch for a while (as in 6 to 12
months) you can indeed get good old 50 db gain antennas on eBay pretty cheap.

Bob

But lots of gain to a HP IAM 81008 active mixer low drive LO. Then a 40db
at least 75 MHz IF. (Pretty sure this is overkill.)
The LO is a HP 8660c for now. Locked to a TBolt.
Thats the reason for the question. I can shift the 8660 to the ausytron 10
MHz.
Regards
Paul.
WB8TSL

On Fri, Mar 31, 2017 at 7:47 PM, Bob kb8tq kb8tq@n1k.org wrote:

Hi

There are a lot of GPS chips that do an I/Q mix down to a low IF. It’s
then (re) sampled from there. The “LO” in this case would down convert to
the low IF ….

Bob

On Mar 31, 2017, at 6:08 PM, Magnus Danielson <

magnus@rubidium.dyndns.org> wrote:

God natt Attila,

On 03/31/2017 11:29 PM, Attila Kinali wrote:

God kväll Magnus,

On Fri, 31 Mar 2017 21:19:00 +0200
Magnus Danielson magnus@rubidium.dyndns.org wrote:

Still fills the function of LO, as the sample and hold operates as a
mixer and the fold-down can be seen as an overtone mix followed by a
sampling of the mix product, so well, it's about the same thing.

"Harmonic mixer" is the word you are looking for :-)

Not necessarily. It could be a locked oscillator too.
Harmonic mixer is another way to go.

Cheers,
Magnus

time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/

mailman/listinfo/time-nuts

and follow the instructions there.

time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.

time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Hi > On Apr 1, 2017, at 11:18 AM, paul swed <paulswedb@gmail.com> wrote: > > Thanks everyone but I am working on an austron 2201a so all the discussions > on modern methods won't help. Whats is interesting is indeed the 2201 down > converts to 80KHz and the does sample in an IQ fashion. Its all discreet > chips and such. If you have a free running VCO in the head end, then indeed you need to lock it to something. An unlocked VCO will not be close enough to frequency to do you any good. The 8660 may or may not be close enough in free run mode. It depends a lot on what standard you have in yours. > Easily traceable and logical. > I think I have what I asked for and am experimenting with active mixers and > IFs made of minicircuit gain stages. > I am using a commercial antenna with 34 db of gain. It says 50db I question > that. That is a very normal antenna gain spec and it was quite common in the era the device you have was designed. I run a number of GPS gizmos that need a 50 db antenna on them. They *might* work with a 40 db setup. They do not work with something in the 20 to 30 db range. If you watch for a while (as in 6 to 12 months) you can indeed get good old 50 db gain antennas on eBay pretty cheap. Bob > But lots of gain to a HP IAM 81008 active mixer low drive LO. Then a 40db > at least 75 MHz IF. (Pretty sure this is overkill.) > The LO is a HP 8660c for now. Locked to a TBolt. > Thats the reason for the question. I can shift the 8660 to the ausytron 10 > MHz. > Regards > Paul. > WB8TSL > > On Fri, Mar 31, 2017 at 7:47 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > >> Hi >> >> >> There are a lot of GPS chips that do an I/Q mix down to a low IF. It’s >> then (re) sampled from there. The “LO” in this case would down convert to >> the low IF …. >> >> Bob >> >>> On Mar 31, 2017, at 6:08 PM, Magnus Danielson < >> magnus@rubidium.dyndns.org> wrote: >>> >>> God natt Attila, >>> >>> On 03/31/2017 11:29 PM, Attila Kinali wrote: >>>> God kväll Magnus, >>>> >>>> On Fri, 31 Mar 2017 21:19:00 +0200 >>>> Magnus Danielson <magnus@rubidium.dyndns.org> wrote: >>>> >>>>> Still fills the function of LO, as the sample and hold operates as a >>>>> mixer and the fold-down can be seen as an overtone mix followed by a >>>>> sampling of the mix product, so well, it's about the same thing. >>>> >>>> "Harmonic mixer" is the word you are looking for :-) >>> >>> Not necessarily. It could be a locked oscillator too. >>> Harmonic mixer is another way to go. >>> >>> Cheers, >>> Magnus >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

LC

Logan Cummings

Tue, Apr 4, 2017 4:32 AM

Dave,

I was able to find [2] here:

http://web.stanford.edu/group/scpnt/gpslab/pubs/papers/Akos_IONGPS_2003_3FreqRX.pdf

[3] was harder, and I don't have a link but a google search for the title
in quotes got me a link on semanticscholar that let me download the PDF.

Interesting stuff!

Hope that helps,
-Logan

On Fri, Mar 31, 2017 at 9:17 AM, David C. Partridge <
david.partridge@perdrix.co.uk> wrote:

links [2] and [3] give 404 errors

Dave

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Attila
Kinali
Sent: 31 March 2017 12:35
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS first LO need to be locked?

[2] "A Prototyping Platform for Multi-Frequency GNSS Receivers", by Akos,
Ene and Thor, 2003 http://waas.stanford.edu/~wwu/papers/gps/PDF/
AkosIONGPS033FreqRX.pdf

[3] "Design of a GPS and Galileo Multi-Frequency Front-End", by Parada,
Chastellain, Botteron, Tawk, Farine, 2009 http://202.194.20.8/proc/
VTC09Spring/DATA/04-04-01.PDF

time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.

Dave, I was able to find [2] here: http://web.stanford.edu/group/scpnt/gpslab/pubs/papers/Akos_IONGPS_2003_3FreqRX.pdf [3] was harder, and I don't have a link but a google search for the title in quotes got me a link on semanticscholar that let me download the PDF. Interesting stuff! Hope that helps, -Logan On Fri, Mar 31, 2017 at 9:17 AM, David C. Partridge < david.partridge@perdrix.co.uk> wrote: > links [2] and [3] give 404 errors > > Dave > > -----Original Message----- > From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Attila > Kinali > Sent: 31 March 2017 12:35 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] GPS first LO need to be locked? > > [2] "A Prototyping Platform for Multi-Frequency GNSS Receivers", by Akos, > Ene and Thor, 2003 http://waas.stanford.edu/~wwu/papers/gps/PDF/ > AkosIONGPS033FreqRX.pdf > > [3] "Design of a GPS and Galileo Multi-Frequency Front-End", by Parada, > Chastellain, Botteron, Tawk, Farine, 2009 http://202.194.20.8/proc/ > VTC09Spring/DATA/04-04-01.PDF > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. >

time-nuts@lists.febo.com

GPS first LO need to be locked?