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- 05-21-2010
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I'm starting to look at building a GPS for some work with IMU/INS
integration.
Are there any reasonable low cost commercial receivers (<$300) where
the hardware
interface is well defined and uyou can load your own code on the
receiver?
If not (I have not found any) I'm planning to use a Maxin2769 GPS
front end chip with a xilinx FPGA and a 32 bit processor. I've done
the FPGA and 32 bit processor part many many times before, just the
GPS is new to me.
Looking at old documentation many of the earliest GPS receivers were
single bit receivers.
With GPS what is the tradeoff/cost for single bit vs multiple bit vs
8 or more bit conversion in the front end. for front end I mean single
conversion down to a 4Mhz or so IF with ~16M or ~32M samples. Is it
low level tracking ability, carrier phase accuracy? I realize this
may be more of a DSP com.dsp question, but GPS is a bit of a strange
duck from a signal stand point.
As news groups like these seem to be going the way of the dodo, is
ther a forum, group, list blog, etc.. where the deep technical details
of GPS are discussed?
Paul
Certainly a very interesting application!
> Are there any reasonable low cost commercial receivers (<$300) where
> the hardware
> interface is well defined and uyou can load your own code on the
> receiver?
> the hardware
> interface is well defined and uyou can load your own code on the
> receiver?
You could take a commercial receiver that gives you raw data
measurement (that should be enough to work on GPS+IMU integration),
but if you want to work also on the DSP... then I don't know...
> If not (I have not found any) I'm planning to use a Maxin2769 GPS
> front end chip with a xilinx FPGA and a 32 bit processor. =A0I've done
> the FPGA and 32 bit processor part many many times before, just the
> GPS is new to me.
> Looking at old documentation many of the earliest GPS receivers were
> single bit receivers.
> front end chip with a xilinx FPGA and a 32 bit processor. =A0I've done
> the FPGA and 32 bit processor part many many times before, just the
> GPS is new to me.
> Looking at old documentation many of the earliest GPS receivers were
> single bit receivers.
Many commercial receivers on the market are still 1 bit only.
As far as I know, only the very latest generation is going with more
than 1...
> With GPS what is the tradeoff/cost for single bit vs multiple bit =A0vs
> 8 or more bit conversion in the front end. for front end I mean single
> conversion down to a 4Mhz or so IF with ~16M or ~32M samples. =A0Is it
> low level tracking ability, carrier phase accuracy? =A0I realize this
> may be more of a DSP com.dsp question, but GPS is a bit of a strange
> duck from a signal stand point.
> 8 or more bit conversion in the front end. for front end I mean single
> conversion down to a 4Mhz or so IF with ~16M or ~32M samples. =A0Is it
> low level tracking ability, carrier phase accuracy? =A0I realize this
> may be more of a DSP com.dsp question, but GPS is a bit of a strange
> duck from a signal stand point.
You have a bit more sensitivity with more bits, but not that you gain
so much.
From 1 to 3 you should 0.7dBm in tracking sensitivity (hope to be
right)
With more bits you have the advantage to be able to apply more
filtering that allows you to deal with jamming.
> As news groups like these seem to be going the way of the dodo, is
> ther a forum, group, list blog, etc.. where the deep technical details
> of GPS are discussed?
> ther a forum, group, list blog, etc.. where the deep technical details
> of GPS are discussed?
Don't know, but if you found them, report here that I'm interested
too :)
claudegps wrote:
>> I'm starting to look at building a GPS for some work with IMU/INS
>> integration.
>> integration.
>
> Certainly a very interesting application!
>
> Certainly a very interesting application!
>
>> Are there any reasonable low cost commercial receivers (<$300) where
>> the hardware
>> interface is well defined and uyou can load your own code on the
>> receiver?
>> the hardware
>> interface is well defined and uyou can load your own code on the
>> receiver?
>
> You could take a commercial receiver that gives you raw data
> measurement (that should be enough to work on GPS+IMU integration),
> but if you want to work also on the DSP... then I don't know...
>
> You could take a commercial receiver that gives you raw data
> measurement (that should be enough to work on GPS+IMU integration),
> but if you want to work also on the DSP... then I don't know...
>
>> If not (I have not found any) I'm planning to use a Maxin2769 GPS
>> front end chip with a xilinx FPGA and a 32 bit processor. I've done
>> the FPGA and 32 bit processor part many many times before, just the
>> GPS is new to me.
>> Looking at old documentation many of the earliest GPS receivers were
>> single bit receivers.
>> front end chip with a xilinx FPGA and a 32 bit processor. I've done
>> the FPGA and 32 bit processor part many many times before, just the
>> GPS is new to me.
>> Looking at old documentation many of the earliest GPS receivers were
>> single bit receivers.
>
> Many commercial receivers on the market are still 1 bit only.
> As far as I know, only the very latest generation is going with more
> than 1...
>
> Many commercial receivers on the market are still 1 bit only.
> As far as I know, only the very latest generation is going with more
> than 1...
>
>> With GPS what is the tradeoff/cost for single bit vs multiple bit vs
>> 8 or more bit conversion in the front end. for front end I mean single
>> conversion down to a 4Mhz or so IF with ~16M or ~32M samples. Is it
>> low level tracking ability, carrier phase accuracy? I realize this
>> may be more of a DSP com.dsp question, but GPS is a bit of a strange
>> duck from a signal stand point.
>> 8 or more bit conversion in the front end. for front end I mean single
>> conversion down to a 4Mhz or so IF with ~16M or ~32M samples. Is it
>> low level tracking ability, carrier phase accuracy? I realize this
>> may be more of a DSP com.dsp question, but GPS is a bit of a strange
>> duck from a signal stand point.
comp.dsp is an appropriate group. I lurk there and have seen GPS
discussed. If nothing else, a well defined question will get you
directed to a suitable source.
>
> You have a bit more sensitivity with more bits, but not that you gain
> so much.
> From 1 to 3 you should 0.7dBm in tracking sensitivity (hope to be
> right)
> With more bits you have the advantage to be able to apply more
> filtering that allows you to deal with jamming.
>
>
> You have a bit more sensitivity with more bits, but not that you gain
> so much.
> From 1 to 3 you should 0.7dBm in tracking sensitivity (hope to be
> right)
> With more bits you have the advantage to be able to apply more
> filtering that allows you to deal with jamming.
>
>
>> As news groups like these seem to be going the way of the dodo, is
>> ther a forum, group, list blog, etc.. where the deep technical details
>> of GPS are discussed?
>> ther a forum, group, list blog, etc.. where the deep technical details
>> of GPS are discussed?
>
> Don't know, but if you found them, report here that I'm interested
> too :)
> Don't know, but if you found them, report here that I'm interested
> too :)
On 10-05-21 0:19 , Paul (unrocket) wrote:
> I'm starting to look at building a GPS for some work with IMU/INS
> integration.
> Are there any reasonable low cost commercial receivers (<$300) where
> the hardware
> interface is well defined and uyou can load your own code on the
> receiver?
> If not (I have not found any) I'm planning to use a Maxin2769 GPS
> front end chip with a xilinx FPGA and a 32 bit processor. I've done
> the FPGA and 32 bit processor part many many times before, just the
> GPS is new to me.
> Looking at old documentation many of the earliest GPS receivers were
> single bit receivers.
> With GPS what is the tradeoff/cost for single bit vs multiple bit vs
> 8 or more bit conversion in the front end. for front end I mean single
> conversion down to a 4Mhz or so IF with ~16M or ~32M samples. Is it
> low level tracking ability, carrier phase accuracy? I realize this
> may be more of a DSP com.dsp question, but GPS is a bit of a strange
> duck from a signal stand point.
> As news groups like these seem to be going the way of the dodo, is
> ther a forum, group, list blog, etc.. where the deep technical details
> of GPS are discussed?
> integration.
> Are there any reasonable low cost commercial receivers (<$300) where
> the hardware
> interface is well defined and uyou can load your own code on the
> receiver?
> If not (I have not found any) I'm planning to use a Maxin2769 GPS
> front end chip with a xilinx FPGA and a 32 bit processor. I've done
> the FPGA and 32 bit processor part many many times before, just the
> GPS is new to me.
> Looking at old documentation many of the earliest GPS receivers were
> single bit receivers.
> With GPS what is the tradeoff/cost for single bit vs multiple bit vs
> 8 or more bit conversion in the front end. for front end I mean single
> conversion down to a 4Mhz or so IF with ~16M or ~32M samples. Is it
> low level tracking ability, carrier phase accuracy? I realize this
> may be more of a DSP com.dsp question, but GPS is a bit of a strange
> duck from a signal stand point.
> As news groups like these seem to be going the way of the dodo, is
> ther a forum, group, list blog, etc.. where the deep technical details
> of GPS are discussed?
Not sure but all the talent has left here...
Try Novatel (Calgary). They manufacture the CMC something Star (or
did). It allows access to the "innards", I believe can be set to 5 or
10 Hz and IIRC had the ability to load your own code into the processor
(ARM based). I'm going from real old memory here - that design is over
10 years old but quite powerful and versatile. I think the price is
more on the order of $500 or so.
--
gmail originated posts are filtered due to spam.
Alan Browne wrote:
Alan Browne wrote:
> On 10-05-21 0:19 , Paul (unrocket) wrote:
>> I'm starting to look at building a GPS for some work with IMU/INS
>> integration.
>> Are there any reasonable low cost commercial receivers (<$300) where
>> the hardware
>> interface is well defined and uyou can load your own code on the
>> receiver?
>> If not (I have not found any) I'm planning to use a Maxin2769 GPS
>> front end chip with a xilinx FPGA and a 32 bit processor. I've done
>> the FPGA and 32 bit processor part many many times before, just the
>> GPS is new to me.
>> Looking at old documentation many of the earliest GPS receivers were
>> single bit receivers.
>> With GPS what is the tradeoff/cost for single bit vs multiple bit vs
>> 8 or more bit conversion in the front end. for front end I mean single
>> conversion down to a 4Mhz or so IF with ~16M or ~32M samples. Is it
>> low level tracking ability, carrier phase accuracy? I realize this
>> may be more of a DSP com.dsp question, but GPS is a bit of a strange
>> duck from a signal stand point.
>> As news groups like these seem to be going the way of the dodo, is
>> ther a forum, group, list blog, etc.. where the deep technical details
>> of GPS are discussed?
>> integration.
>> Are there any reasonable low cost commercial receivers (<$300) where
>> the hardware
>> interface is well defined and uyou can load your own code on the
>> receiver?
>> If not (I have not found any) I'm planning to use a Maxin2769 GPS
>> front end chip with a xilinx FPGA and a 32 bit processor. I've done
>> the FPGA and 32 bit processor part many many times before, just the
>> GPS is new to me.
>> Looking at old documentation many of the earliest GPS receivers were
>> single bit receivers.
>> With GPS what is the tradeoff/cost for single bit vs multiple bit vs
>> 8 or more bit conversion in the front end. for front end I mean single
>> conversion down to a 4Mhz or so IF with ~16M or ~32M samples. Is it
>> low level tracking ability, carrier phase accuracy? I realize this
>> may be more of a DSP com.dsp question, but GPS is a bit of a strange
>> duck from a signal stand point.
>> As news groups like these seem to be going the way of the dodo, is
>> ther a forum, group, list blog, etc.. where the deep technical details
>> of GPS are discussed?
>
> Not sure but all the talent has left here...
>
> Try Novatel (Calgary). They manufacture the CMC something Star (or
> did). It allows access to the "innards", I believe can be set to 5 or
> 10 Hz and IIRC had the ability to load your own code into the processor
> (ARM based). I'm going from real old memory here - that design is over
> 10 years old but quite powerful and versatile. I think the price is
> more on the order of $500 or so.
>
> Not sure but all the talent has left here...
>
> Try Novatel (Calgary). They manufacture the CMC something Star (or
> did). It allows access to the "innards", I believe can be set to 5 or
> 10 Hz and IIRC had the ability to load your own code into the processor
> (ARM based). I'm going from real old memory here - that design is over
> 10 years old but quite powerful and versatile. I think the price is
> more on the order of $500 or so.
>
> On 10-05-21 0:19 , Paul (unrocket) wrote:
>> I'm starting to look at building a GPS for some work with IMU/INS
>> integration.
>> Are there any reasonable low cost commercial receivers (<$300) where
>> the hardware
>> interface is well defined and uyou can load your own code on the
>> receiver?
>> If not (I have not found any) I'm planning to use a Maxin2769 GPS
>> front end chip with a xilinx FPGA and a 32 bit processor. I've done
>> the FPGA and 32 bit processor part many many times before, just the
>> GPS is new to me.
>> Looking at old documentation many of the earliest GPS receivers were
>> single bit receivers.
>> With GPS what is the tradeoff/cost for single bit vs multiple bit vs
>> 8 or more bit conversion in the front end. for front end I mean single
>> conversion down to a 4Mhz or so IF with ~16M or ~32M samples. Is it
>> low level tracking ability, carrier phase accuracy? I realize this
>> may be more of a DSP com.dsp question, but GPS is a bit of a strange
>> duck from a signal stand point.
>> As news groups like these seem to be going the way of the dodo, is
>> ther a forum, group, list blog, etc.. where the deep technical details
>> of GPS are discussed?
>> integration.
>> Are there any reasonable low cost commercial receivers (<$300) where
>> the hardware
>> interface is well defined and uyou can load your own code on the
>> receiver?
>> If not (I have not found any) I'm planning to use a Maxin2769 GPS
>> front end chip with a xilinx FPGA and a 32 bit processor. I've done
>> the FPGA and 32 bit processor part many many times before, just the
>> GPS is new to me.
>> Looking at old documentation many of the earliest GPS receivers were
>> single bit receivers.
>> With GPS what is the tradeoff/cost for single bit vs multiple bit vs
>> 8 or more bit conversion in the front end. for front end I mean single
>> conversion down to a 4Mhz or so IF with ~16M or ~32M samples. Is it
>> low level tracking ability, carrier phase accuracy? I realize this
>> may be more of a DSP com.dsp question, but GPS is a bit of a strange
>> duck from a signal stand point.
>> As news groups like these seem to be going the way of the dodo, is
>> ther a forum, group, list blog, etc.. where the deep technical details
>> of GPS are discussed?
>
> Not sure but all the talent has left here...
>
> Try Novatel (Calgary). They manufacture the CMC something Star (or
> did). It allows access to the "innards", I believe can be set to 5 or
> 10 Hz and IIRC had the ability to load your own code into the processor
> (ARM based). I'm going from real old memory here - that design is over
> 10 years old but quite powerful and versatile. I think the price is
> more on the order of $500 or so.
>
> Not sure but all the talent has left here...
>
> Try Novatel (Calgary). They manufacture the CMC something Star (or
> did). It allows access to the "innards", I believe can be set to 5 or
> 10 Hz and IIRC had the ability to load your own code into the processor
> (ARM based). I'm going from real old memory here - that design is over
> 10 years old but quite powerful and versatile. I think the price is
> more on the order of $500 or so.
>
Looks like a very good lead.
http://www.google.com/search?q=Novatel+Calgary+CMC+Star
seems to give links relevant to your goal. I only had a couple of
minutes to glance at random links.
- 25 Free Symbian GPS Software
- Satellite Navigation
- 2010-03-31
- 40 Free Linux GPS Software
- Satellite Navigation
- 2010-02-09
> integration.