Beidou Launch Completes Regional Nav System

Discussion in 'Global Navigation Satellite Systems' started by Sam Wormley, Dec 8, 2011.

  1. Sam Wormley

    Sam Wormley Guest

    Beidou Launch Completes *Regional* Nav System

    http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regional-nav-system-12375

    December 6, 2011

    "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    satellite was launched on December 1 from Xichang, China. Exact launch
    time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
    satellite attached achieved a geosynchronous transfer orbit and the
    satellite subsequently separated according to NORAD/JSpOC. As of
    December 7, the satellite is still in geosynchronous transfer orbit
    (GTO), orbiting the Earth about twice a day with a highly eliptic orbit.
    To get to geosynchronous orbit, the satellite's apogee kick motor will
    have to be fired. The satellite is not drifting to its intended orbit,
    for example, like a GLONASS satellite might".

    See:
    http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regional-nav-system-12375
     
    Sam Wormley, Dec 8, 2011
    #1
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  2. Sam Wormley

    macpacheco Guest

    On Dec 8, 2:32 pm, Sam Wormley <> wrote:
    > Beidou Launch Completes *Regional* Nav System
    >
    > http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...
    >
    > December 6, 2011
    >
    > "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    > satellite was launched on December 1 from Xichang, China. Exact launch
    > time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
    > satellite attached achieved a geosynchronous transfer orbit and the
    > satellite subsequently separated according to NORAD/JSpOC. As of
    > December 7, the satellite is still in geosynchronous transfer orbit
    > (GTO), orbiting the Earth about twice a day with a highly eliptic orbit.
    > To get to geosynchronous orbit, the satellite's apogee kick motor will
    > have to be fired. The satellite is not drifting to its intended orbit,
    > for example, like a GLONASS satellite might".
    >
    > See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi....


    Thanks Sam,

    The persistent question is where is the ICD !!!
    Per the usual China stonewalls the open market every time it's to
    their advantage.
    Boycott Compass. Boycott China (to the largest extent possible).
    We must make them hurts somehow, so they understand the only
    acceptable behavior is to be open, democratic, and fair trading
    practices.

    Marcelo Pacheco
     
    macpacheco, Dec 8, 2011
    #2
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  3. Sam Wormley

    Alan Browne Guest

    On 2011-12-08 15:48 , macpacheco wrote:
    > On Dec 8, 2:32 pm, Sam Wormley<> wrote:
    >> Beidou Launch Completes *Regional* Nav System
    >>
    >> http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...
    >>
    >> December 6, 2011
    >>
    >> "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    >> satellite was launched on December 1 from Xichang, China. Exact launch
    >> time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
    >> satellite attached achieved a geosynchronous transfer orbit and the
    >> satellite subsequently separated according to NORAD/JSpOC. As of
    >> December 7, the satellite is still in geosynchronous transfer orbit
    >> (GTO), orbiting the Earth about twice a day with a highly eliptic orbit.
    >> To get to geosynchronous orbit, the satellite's apogee kick motor will
    >> have to be fired. The satellite is not drifting to its intended orbit,
    >> for example, like a GLONASS satellite might".
    >>
    >> See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >
    > Thanks Sam,
    >
    > The persistent question is where is the ICD !!!
    > Per the usual China stonewalls the open market every time it's to
    > their advantage.


    http://www.insidegnss.com/node/1712

    > Boycott Compass. Boycott China (to the largest extent possible).
    > We must make them hurts somehow, so they understand the only
    > acceptable behavior is to be open, democratic, and fair trading
    > practices.


    The Chinese will never espouse fair trade, it is a one-way blanket pull.
    In the meantime avoid buying from them (you can't boycott 100% - they
    are into everything at the lowest cost and buyers around the world
    gravitate to low prices).

    For satellite positioning the best thing is to wait until someone like
    Garmin makes a receiver with GPS+GLONASS+Galileo+Beidou-2.

    Garmin for example (at least to present) make their receivers in Taiwan.

    --
    "I see!" said the blind man as he picked up his hammer and saw.
     
    Alan Browne, Dec 8, 2011
    #3
  4. Sam Wormley

    miso Guest

    On 12/8/2011 1:14 PM, Alan Browne wrote:
    > On 2011-12-08 15:48 , macpacheco wrote:
    >> On Dec 8, 2:32 pm, Sam Wormley<> wrote:
    >>> Beidou Launch Completes *Regional* Nav System
    >>>
    >>> http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...
    >>>
    >>> December 6, 2011
    >>>
    >>> "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    >>> satellite was launched on December 1 from Xichang, China. Exact launch
    >>> time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
    >>> satellite attached achieved a geosynchronous transfer orbit and the
    >>> satellite subsequently separated according to NORAD/JSpOC. As of
    >>> December 7, the satellite is still in geosynchronous transfer orbit
    >>> (GTO), orbiting the Earth about twice a day with a highly eliptic orbit.
    >>> To get to geosynchronous orbit, the satellite's apogee kick motor will
    >>> have to be fired. The satellite is not drifting to its intended orbit,
    >>> for example, like a GLONASS satellite might".
    >>>
    >>> See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...
    >>>

    >>
    >> Thanks Sam,
    >>
    >> The persistent question is where is the ICD !!!
    >> Per the usual China stonewalls the open market every time it's to
    >> their advantage.

    >
    > http://www.insidegnss.com/node/1712
    >
    >> Boycott Compass. Boycott China (to the largest extent possible).
    >> We must make them hurts somehow, so they understand the only
    >> acceptable behavior is to be open, democratic, and fair trading
    >> practices.

    >
    > The Chinese will never espouse fair trade, it is a one-way blanket pull.
    > In the meantime avoid buying from them (you can't boycott 100% - they
    > are into everything at the lowest cost and buyers around the world
    > gravitate to low prices).
    >
    > For satellite positioning the best thing is to wait until someone like
    > Garmin makes a receiver with GPS+GLONASS+Galileo+Beidou-2.
    >
    > Garmin for example (at least to present) make their receivers in Taiwan.
    >


    I assume current generation of GPSs are heavily DSP if not SDR, but
    often the more things you make a device do, the less it does well.
    Smartphones are the perfect example. Jack of all trades, master of none.
    Well a few brands have decent voice quality, so maybe master of one thing.
     
    miso, Dec 10, 2011
    #4
  5. Sam Wormley

    Alan Browne Guest

    On 2011-12-10 01:15 , miso wrote:
    > On 12/8/2011 1:14 PM, Alan Browne wrote:
    >> On 2011-12-08 15:48 , macpacheco wrote:
    >>> On Dec 8, 2:32 pm, Sam Wormley<> wrote:
    >>>> Beidou Launch Completes *Regional* Nav System
    >>>>
    >>>> http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...
    >>>>
    >>>>
    >>>> December 6, 2011
    >>>>
    >>>> "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    >>>> satellite was launched on December 1 from Xichang, China. Exact launch
    >>>> time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
    >>>> satellite attached achieved a geosynchronous transfer orbit and the
    >>>> satellite subsequently separated according to NORAD/JSpOC. As of
    >>>> December 7, the satellite is still in geosynchronous transfer orbit
    >>>> (GTO), orbiting the Earth about twice a day with a highly eliptic
    >>>> orbit.
    >>>> To get to geosynchronous orbit, the satellite's apogee kick motor will
    >>>> have to be fired. The satellite is not drifting to its intended orbit,
    >>>> for example, like a GLONASS satellite might".
    >>>>
    >>>> See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...
    >>>>
    >>>>
    >>>
    >>> Thanks Sam,
    >>>
    >>> The persistent question is where is the ICD !!!
    >>> Per the usual China stonewalls the open market every time it's to
    >>> their advantage.

    >>
    >> http://www.insidegnss.com/node/1712
    >>
    >>> Boycott Compass. Boycott China (to the largest extent possible).
    >>> We must make them hurts somehow, so they understand the only
    >>> acceptable behavior is to be open, democratic, and fair trading
    >>> practices.

    >>
    >> The Chinese will never espouse fair trade, it is a one-way blanket pull.
    >> In the meantime avoid buying from them (you can't boycott 100% - they
    >> are into everything at the lowest cost and buyers around the world
    >> gravitate to low prices).
    >>
    >> For satellite positioning the best thing is to wait until someone like
    >> Garmin makes a receiver with GPS+GLONASS+Galileo+Beidou-2.
    >>
    >> Garmin for example (at least to present) make their receivers in Taiwan.
    >>

    >
    > I assume current generation of GPSs are heavily DSP if not SDR, but
    > often the more things you make a device do, the less it does well.
    > Smartphones are the perfect example. Jack of all trades, master of none.
    > Well a few brands have decent voice quality, so maybe master of one thing.


    GPS's use dedicated hardware correlator channels driven by software to
    detect and track the signal. It is relatively cheap and easy to add
    channels although those for GPS are different than those for GLONASS and
    will also be different for Galileo and Compass. Some GPS receivers that
    cost a few dollars (in bulk) have about 60 channels. When future civil
    channels are added they will require more hardware channels as well.

    They are cheap and are not usually DSP|SDR (it's just not the cheapest
    way to go, esp. for low power consumption devices).

    So, you can indeed have "more" and not lose anything at all. The
    question then becomes optimizing the algorithms to truly get the best
    information for position determination.

    In GPS it's called "over determination". But unless craftily
    implemented, using all sources for a position fix could lead to a
    greater error when the worst satellite PR's are used with the best. An
    example is mixing GPS with GLONASS (the later being a little less
    accurate than GPS at present).

    Smartphones that I know of use very low power GPS devices and are also
    driven "lazily" to conserve power. That aside, the performance of my
    iPhone 4 as a GPS is more than adequate for what it was designed to do
    (get me to the restaurant). In comparing with dedicated GPS', it has an
    error range of about 5-20 metres where the dedicated GPS is 3-5 metres
    in the same conditions. The newer iPhone 4S also has GLONASS so
    presumably acquires quicker, but if driven lazily, is probably not more
    accurate than the iPhone 4.

    --
    "I see!" said the blind man as he picked up his hammer and saw.
     
    Alan Browne, Dec 10, 2011
    #5
  6. Sam Wormley

    macpacheco Guest

    On Dec 10, 4:15 am, miso <> wrote:
    > On 12/8/2011 1:14 PM, Alan Browne wrote:
    >
    >
    >
    >
    >
    >
    >
    >
    >
    > > On 2011-12-08 15:48 , macpacheco wrote:
    > >> On Dec 8, 2:32 pm, Sam Wormley<> wrote:
    > >>> Beidou Launch Completes *Regional* Nav System

    >
    > >>>http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi....

    >
    > >>> December 6, 2011

    >
    > >>> "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    > >>> satellite was launched on December 1 from Xichang, China. Exact launch
    > >>> time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
    > >>> satellite attached achieved a geosynchronous transfer orbit and the
    > >>> satellite subsequently separated according to NORAD/JSpOC. As of
    > >>> December 7, the satellite is still in geosynchronous transfer orbit
    > >>> (GTO), orbiting the Earth about twice a day with a highly eliptic orbit.
    > >>> To get to geosynchronous orbit, the satellite's apogee kick motor will
    > >>> have to be fired. The satellite is not drifting to its intended orbit,
    > >>> for example, like a GLONASS satellite might".

    >
    > >>> See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >
    > >> Thanks Sam,

    >
    > >> The persistent question is where is the ICD !!!
    > >> Per the usual China stonewalls the open market every time it's to
    > >> their advantage.

    >
    > >http://www.insidegnss.com/node/1712

    >
    > >> Boycott Compass. Boycott China (to the largest extent possible).
    > >> We must make them hurts somehow, so they understand the only
    > >> acceptable behavior is to be open, democratic, and fair trading
    > >> practices.

    >
    > > The Chinese will never espouse fair trade, it is a one-way blanket pull..
    > > In the meantime avoid buying from them (you can't boycott 100% - they
    > > are into everything at the lowest cost and buyers around the world
    > > gravitate to low prices).

    >
    > > For satellite positioning the best thing is to wait until someone like
    > > Garmin makes a receiver with GPS+GLONASS+Galileo+Beidou-2.

    >
    > > Garmin for example (at least to present) make their receivers in Taiwan..

    >
    > I assume current generation of GPSs are heavily DSP if not SDR, but
    > often the more things you make a device do, the less it does well.
    > Smartphones are the perfect example. Jack of all trades, master of none.
    > Well a few brands have decent voice quality, so maybe master of one thing..


    SDR don't make a lot of sense for circuitry planned to sell millions
    (if not tens of millions) units over the next few years.
    Specially for single frequency equipment that have no requirement for
    field upgrades.
    Besides companies like Garmin force customers to buy brand new units
    to get new features. When was the last time you saw a software upgrade
    for any Garmin handheld ? Products in the multi thousand dollar range
    do get some paid upgrades, but not <1000 USD products.
    SDRs are great for open flexible products and perhaps some low volume
    specialized receivers.
    In anything planned to ship millions of units bill of materials cost
    is paramount. The more functionality can be integrated into one large
    combo chip, the better.
    SDRs make sense for multi frequency, multi purpose stuff.

    Marcelo Pacheco
     
    macpacheco, Dec 10, 2011
    #6
  7. Sam Wormley

    macpacheco Guest

    On Dec 10, 12:47 pm, Alan Browne <>
    wrote:
    > On 2011-12-10 01:15 , miso wrote:
    >
    >
    >
    >
    >
    >
    >
    >
    >
    > > On 12/8/2011 1:14 PM, Alan Browne wrote:
    > >> On 2011-12-08 15:48 , macpacheco wrote:
    > >>> On Dec 8, 2:32 pm, Sam Wormley<> wrote:
    > >>>> Beidou Launch Completes *Regional* Nav System

    >
    > >>>>http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi....

    >
    > >>>> December 6, 2011

    >
    > >>>> "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    > >>>> satellite was launched on December 1 from Xichang, China. Exact launch
    > >>>> time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
    > >>>> satellite attached achieved a geosynchronous transfer orbit and the
    > >>>> satellite subsequently separated according to NORAD/JSpOC. As of
    > >>>> December 7, the satellite is still in geosynchronous transfer orbit
    > >>>> (GTO), orbiting the Earth about twice a day with a highly eliptic
    > >>>> orbit.
    > >>>> To get to geosynchronous orbit, the satellite's apogee kick motor will
    > >>>> have to be fired. The satellite is not drifting to its intended orbit,
    > >>>> for example, like a GLONASS satellite might".

    >
    > >>>> See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >
    > >>> Thanks Sam,

    >
    > >>> The persistent question is where is the ICD !!!
    > >>> Per the usual China stonewalls the open market every time it's to
    > >>> their advantage.

    >
    > >>http://www.insidegnss.com/node/1712

    >
    > >>> Boycott Compass. Boycott China (to the largest extent possible).
    > >>> We must make them hurts somehow, so they understand the only
    > >>> acceptable behavior is to be open, democratic, and fair trading
    > >>> practices.

    >
    > >> The Chinese will never espouse fair trade, it is a one-way blanket pull.
    > >> In the meantime avoid buying from them (you can't boycott 100% - they
    > >> are into everything at the lowest cost and buyers around the world
    > >> gravitate to low prices).

    >
    > >> For satellite positioning the best thing is to wait until someone like
    > >> Garmin makes a receiver with GPS+GLONASS+Galileo+Beidou-2.

    >
    > >> Garmin for example (at least to present) make their receivers in Taiwan.

    >
    > > I assume current generation of GPSs are heavily DSP if not SDR, but
    > > often the more things you make a device do, the less it does well.
    > > Smartphones are the perfect example. Jack of all trades, master of none..
    > > Well a few brands have decent voice quality, so maybe master of one thing.

    >
    > GPS's use dedicated hardware correlator channels driven by software to
    > detect and track the signal.  It is relatively cheap and easy to add
    > channels although those for GPS are different than those for GLONASS and
    > will also be different for Galileo and Compass.  Some GPS receivers that
    > cost a few dollars (in bulk) have about 60 channels.  When future civil
    > channels are added they will require more hardware channels as well.
    >
    > They are cheap and are not usually DSP|SDR (it's just not the cheapest
    > way to go, esp. for low power consumption devices).
    >
    > So, you can indeed have "more" and not lose anything at all.  The
    > question then becomes optimizing the algorithms to truly get the best
    > information for position determination.
    >
    > In GPS it's called "over determination".  But unless craftily
    > implemented, using all sources for a position fix could lead to a
    > greater error when the worst satellite PR's are used with the best.  An
    > example is mixing GPS with GLONASS (the later being a little less
    > accurate than GPS at present).
    >
    > Smartphones that I know of use very low power GPS devices and are also
    > driven "lazily" to conserve power.  That aside, the performance of my
    > iPhone 4 as a GPS is more than adequate for what it was designed to do
    > (get me to the restaurant).  In comparing with dedicated GPS', it has an
    > error range of about 5-20 metres where the dedicated GPS is 3-5 metres
    > in the same conditions.  The newer iPhone 4S also has GLONASS so
    > presumably acquires quicker, but if driven lazily, is probably not more
    > accurate than the iPhone 4.
    >
    > --
    > "I see!" said the blind man as he picked up his hammer and saw.


    Interesting your statement that GLONASS accuracy is lower than GPS.
    I'm not trying to pick a fight, just to raise the fact that PDOP
    charts for GLONASS actually look better than those for GPS.
    Sources:
    GPS: http://www.nstb.tc.faa.gov/incoming/NA_MaxPDOP.png
    GLONASS: http://www.gpsworld.com/gnss-system/news/glonass-fully-operational-first-time-15-years-12379
    Of course PDOP is about signal geometry, it doesn't take into account
    individual satellite clock+ephemeris performance.
    Hopefully in another 2-3 of years, the older half of GLONASS
    satellites will be replaced, which will improve clock performance
    quite a bit.

    For instance PRN1 performance isn't great, while PRN25 is performing
    great. Hopefully the issues on PRN1 (IIF-2) are a one bird issue that
    will be avoided in the future. Source: http://adn.agi.com/GNSSWeb/PAFPSFViewer.aspx
    (the last chart shows user range error assessment).

    Marcelo
     
    macpacheco, Dec 10, 2011
    #7
  8. Sam Wormley

    miso Guest

    On 12/10/2011 1:40 PM, macpacheco wrote:
    > On Dec 10, 4:15 am, miso<> wrote:
    >> On 12/8/2011 1:14 PM, Alan Browne wrote:
    >>
    >>
    >>
    >>
    >>
    >>
    >>
    >>
    >>
    >>> On 2011-12-08 15:48 , macpacheco wrote:
    >>>> On Dec 8, 2:32 pm, Sam Wormley<> wrote:
    >>>>> Beidou Launch Completes *Regional* Nav System

    >>
    >>>>> http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >>
    >>>>> December 6, 2011

    >>
    >>>>> "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    >>>>> satellite was launched on December 1 from Xichang, China. Exact launch
    >>>>> time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
    >>>>> satellite attached achieved a geosynchronous transfer orbit and the
    >>>>> satellite subsequently separated according to NORAD/JSpOC. As of
    >>>>> December 7, the satellite is still in geosynchronous transfer orbit
    >>>>> (GTO), orbiting the Earth about twice a day with a highly eliptic orbit.
    >>>>> To get to geosynchronous orbit, the satellite's apogee kick motor will
    >>>>> have to be fired. The satellite is not drifting to its intended orbit,
    >>>>> for example, like a GLONASS satellite might".

    >>
    >>>>> See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >>
    >>>> Thanks Sam,

    >>
    >>>> The persistent question is where is the ICD !!!
    >>>> Per the usual China stonewalls the open market every time it's to
    >>>> their advantage.

    >>
    >>> http://www.insidegnss.com/node/1712

    >>
    >>>> Boycott Compass. Boycott China (to the largest extent possible).
    >>>> We must make them hurts somehow, so they understand the only
    >>>> acceptable behavior is to be open, democratic, and fair trading
    >>>> practices.

    >>
    >>> The Chinese will never espouse fair trade, it is a one-way blanket pull.
    >>> In the meantime avoid buying from them (you can't boycott 100% - they
    >>> are into everything at the lowest cost and buyers around the world
    >>> gravitate to low prices).

    >>
    >>> For satellite positioning the best thing is to wait until someone like
    >>> Garmin makes a receiver with GPS+GLONASS+Galileo+Beidou-2.

    >>
    >>> Garmin for example (at least to present) make their receivers in Taiwan.

    >>
    >> I assume current generation of GPSs are heavily DSP if not SDR, but
    >> often the more things you make a device do, the less it does well.
    >> Smartphones are the perfect example. Jack of all trades, master of none.
    >> Well a few brands have decent voice quality, so maybe master of one thing.

    >
    > SDR don't make a lot of sense for circuitry planned to sell millions
    > (if not tens of millions) units over the next few years.
    > Specially for single frequency equipment that have no requirement for
    > field upgrades.
    > Besides companies like Garmin force customers to buy brand new units
    > to get new features. When was the last time you saw a software upgrade
    > for any Garmin handheld ? Products in the multi thousand dollar range
    > do get some paid upgrades, but not<1000 USD products.
    > SDRs are great for open flexible products and perhaps some low volume
    > specialized receivers.
    > In anything planned to ship millions of units bill of materials cost
    > is paramount. The more functionality can be integrated into one large
    > combo chip, the better.
    > SDRs make sense for multi frequency, multi purpose stuff.
    >
    > Marcelo Pacheco


    I flashed my emap more times that I can remember. I don't recall if I
    ever flashed the GPSMap60.

    Incidentally, my Blackberry GPS claims 2 meter EPE. Reality, who knows.
    It just bugs me to see people use smartphones as GPSs on the trails.
    Depending on a phone gps is a bad idea. For one thing, slapping in a set
    of AA cells isn't so simple. I have one of those AA to USB power
    sources. Never even cracked open the plastic, but I carried it for a few
    years for emergency purposes. When the EU forced all phones to go
    microusb, I didn't bother to get another one.

    A friend was trying to locate some coordinates with her iphone. Easily
    off 50ft. I gave her an old Lowrance.

    It used to be in the day if somebody gave you some coordinates, you
    could trust them. Nowadays you have to ask what gear they used to get
    the coordinates.
     
    miso, Dec 10, 2011
    #8
  9. Sam Wormley

    macpacheco Guest

    On Dec 10, 8:47 pm, miso <> wrote:
    > On 12/10/2011 1:40 PM, macpacheco wrote:
    >
    >
    >
    >
    >
    >
    >
    >
    >
    > > On Dec 10, 4:15 am, miso<>  wrote:
    > >> On 12/8/2011 1:14 PM, Alan Browne wrote:

    >
    > >>> On 2011-12-08 15:48 , macpacheco wrote:
    > >>>> On Dec 8, 2:32 pm, Sam Wormley<>  wrote:
    > >>>>> Beidou Launch Completes *Regional* Nav System

    >
    > >>>>>http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >
    > >>>>> December 6, 2011

    >
    > >>>>> "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    > >>>>> satellite was launched on December 1 from Xichang, China. Exact launch
    > >>>>> time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket withthe
    > >>>>> satellite attached achieved a geosynchronous transfer orbit and the
    > >>>>> satellite subsequently separated according to NORAD/JSpOC. As of
    > >>>>> December 7, the satellite is still in geosynchronous transfer orbit
    > >>>>> (GTO), orbiting the Earth about twice a day with a highly eliptic orbit.
    > >>>>> To get to geosynchronous orbit, the satellite's apogee kick motor will
    > >>>>> have to be fired. The satellite is not drifting to its intended orbit,
    > >>>>> for example, like a GLONASS satellite might".

    >
    > >>>>> See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >
    > >>>> Thanks Sam,

    >
    > >>>> The persistent question is where is the ICD !!!
    > >>>> Per the usual China stonewalls the open market every time it's to
    > >>>> their advantage.

    >
    > >>>http://www.insidegnss.com/node/1712

    >
    > >>>> Boycott Compass. Boycott China (to the largest extent possible).
    > >>>> We must make them hurts somehow, so they understand the only
    > >>>> acceptable behavior is to be open, democratic, and fair trading
    > >>>> practices.

    >
    > >>> The Chinese will never espouse fair trade, it is a one-way blanket pull.
    > >>> In the meantime avoid buying from them (you can't boycott 100% - they
    > >>> are into everything at the lowest cost and buyers around the world
    > >>> gravitate to low prices).

    >
    > >>> For satellite positioning the best thing is to wait until someone like
    > >>> Garmin makes a receiver with GPS+GLONASS+Galileo+Beidou-2.

    >
    > >>> Garmin for example (at least to present) make their receivers in Taiwan.

    >
    > >> I assume current generation of GPSs are heavily DSP if not SDR, but
    > >> often the more things you make a device do, the less it does well.
    > >> Smartphones are the perfect example. Jack of all trades, master of none.
    > >> Well a few brands have decent voice quality, so maybe master of one thing.

    >
    > > SDR don't make a lot of sense for circuitry planned to sell millions
    > > (if not tens of millions) units over the next few years.
    > > Specially for single frequency equipment that have no requirement for
    > > field upgrades.
    > > Besides companies like Garmin force customers to buy brand new units
    > > to get new features. When was the last time you saw a software upgrade
    > > for any Garmin handheld ? Products in the multi thousand dollar range
    > > do get some paid upgrades, but not<1000 USD products.
    > > SDRs are great for open flexible products and perhaps some low volume
    > > specialized receivers.
    > > In anything planned to ship millions of units bill of materials cost
    > > is paramount. The more functionality can be integrated into one large
    > > combo chip, the better.
    > > SDRs make sense for multi frequency, multi purpose stuff.

    >
    > > Marcelo Pacheco

    >
    > I flashed my emap more times that I can remember. I don't recall if I
    > ever flashed the GPSMap60.
    >
    > Incidentally, my Blackberry GPS claims 2 meter EPE. Reality, who knows.
    > It just bugs me to see people use smartphones as GPSs on the trails.
    > Depending on a phone gps is a bad idea. For one thing, slapping in a set
    > of AA cells isn't so simple. I have one of those AA to USB power
    > sources. Never even cracked open the plastic, but I carried it for a few
    > years for emergency purposes. When the EU forced all phones to go
    > microusb, I didn't bother to get another one.
    >
    > A friend was trying to locate some coordinates with her iphone. Easily
    > off 50ft. I gave her an old Lowrance.
    >
    > It used to be in the day if somebody gave you some coordinates, you
    > could trust them. Nowadays you have to ask what gear they used to get
    > the coordinates.


    Did any of those re-flashing were for new functionality ? Bug fixes
    maybe. But new functionality, I think not...

    All kinds of devices should be built with the physical equipment
    designed to at least 5 yrs, allowing the customer to upgrade to use
    new functionality often.

    That's cheaper for the consumer, better for the environment, and might
    even be more profitable for the manufacturer.

    10 yrs ago this might not be possible, even 5 yrs ago might have been
    a challenge. But today with very powerful low power consumption CPUs
    and DSPs, it would make far more sense to do it that way.

    One can hope.
     
    macpacheco, Dec 10, 2011
    #9
  10. Sam Wormley

    miso Guest

    On 12/10/2011 3:56 PM, macpacheco wrote:
    > On Dec 10, 8:47 pm, miso<> wrote:
    >> On 12/10/2011 1:40 PM, macpacheco wrote:
    >>
    >>
    >>
    >>
    >>
    >>
    >>
    >>
    >>
    >>> On Dec 10, 4:15 am, miso<> wrote:
    >>>> On 12/8/2011 1:14 PM, Alan Browne wrote:

    >>
    >>>>> On 2011-12-08 15:48 , macpacheco wrote:
    >>>>>> On Dec 8, 2:32 pm, Sam Wormley<> wrote:
    >>>>>>> Beidou Launch Completes *Regional* Nav System

    >>
    >>>>>>> http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >>
    >>>>>>> December 6, 2011

    >>
    >>>>>>> "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    >>>>>>> satellite was launched on December 1 from Xichang, China. Exact launch
    >>>>>>> time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
    >>>>>>> satellite attached achieved a geosynchronous transfer orbit and the
    >>>>>>> satellite subsequently separated according to NORAD/JSpOC. As of
    >>>>>>> December 7, the satellite is still in geosynchronous transfer orbit
    >>>>>>> (GTO), orbiting the Earth about twice a day with a highly eliptic orbit.
    >>>>>>> To get to geosynchronous orbit, the satellite's apogee kick motor will
    >>>>>>> have to be fired. The satellite is not drifting to its intended orbit,
    >>>>>>> for example, like a GLONASS satellite might".

    >>
    >>>>>>> See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >>
    >>>>>> Thanks Sam,

    >>
    >>>>>> The persistent question is where is the ICD !!!
    >>>>>> Per the usual China stonewalls the open market every time it's to
    >>>>>> their advantage.

    >>
    >>>>> http://www.insidegnss.com/node/1712

    >>
    >>>>>> Boycott Compass. Boycott China (to the largest extent possible).
    >>>>>> We must make them hurts somehow, so they understand the only
    >>>>>> acceptable behavior is to be open, democratic, and fair trading
    >>>>>> practices.

    >>
    >>>>> The Chinese will never espouse fair trade, it is a one-way blanket pull.
    >>>>> In the meantime avoid buying from them (you can't boycott 100% - they
    >>>>> are into everything at the lowest cost and buyers around the world
    >>>>> gravitate to low prices).

    >>
    >>>>> For satellite positioning the best thing is to wait until someone like
    >>>>> Garmin makes a receiver with GPS+GLONASS+Galileo+Beidou-2.

    >>
    >>>>> Garmin for example (at least to present) make their receivers in Taiwan.

    >>
    >>>> I assume current generation of GPSs are heavily DSP if not SDR, but
    >>>> often the more things you make a device do, the less it does well.
    >>>> Smartphones are the perfect example. Jack of all trades, master of none.
    >>>> Well a few brands have decent voice quality, so maybe master of one thing.

    >>
    >>> SDR don't make a lot of sense for circuitry planned to sell millions
    >>> (if not tens of millions) units over the next few years.
    >>> Specially for single frequency equipment that have no requirement for
    >>> field upgrades.
    >>> Besides companies like Garmin force customers to buy brand new units
    >>> to get new features. When was the last time you saw a software upgrade
    >>> for any Garmin handheld ? Products in the multi thousand dollar range
    >>> do get some paid upgrades, but not<1000 USD products.
    >>> SDRs are great for open flexible products and perhaps some low volume
    >>> specialized receivers.
    >>> In anything planned to ship millions of units bill of materials cost
    >>> is paramount. The more functionality can be integrated into one large
    >>> combo chip, the better.
    >>> SDRs make sense for multi frequency, multi purpose stuff.

    >>
    >>> Marcelo Pacheco

    >>
    >> I flashed my emap more times that I can remember. I don't recall if I
    >> ever flashed the GPSMap60.
    >>
    >> Incidentally, my Blackberry GPS claims 2 meter EPE. Reality, who knows.
    >> It just bugs me to see people use smartphones as GPSs on the trails.
    >> Depending on a phone gps is a bad idea. For one thing, slapping in a set
    >> of AA cells isn't so simple. I have one of those AA to USB power
    >> sources. Never even cracked open the plastic, but I carried it for a few
    >> years for emergency purposes. When the EU forced all phones to go
    >> microusb, I didn't bother to get another one.
    >>
    >> A friend was trying to locate some coordinates with her iphone. Easily
    >> off 50ft. I gave her an old Lowrance.
    >>
    >> It used to be in the day if somebody gave you some coordinates, you
    >> could trust them. Nowadays you have to ask what gear they used to get
    >> the coordinates.

    >
    > Did any of those re-flashing were for new functionality ? Bug fixes
    > maybe. But new functionality, I think not...
    >
    > All kinds of devices should be built with the physical equipment
    > designed to at least 5 yrs, allowing the customer to upgrade to use
    > new functionality often.
    >
    > That's cheaper for the consumer, better for the environment, and might
    > even be more profitable for the manufacturer.
    >
    > 10 yrs ago this might not be possible, even 5 yrs ago might have been
    > a challenge. But today with very powerful low power consumption CPUs
    > and DSPs, it would make far more sense to do it that way.
    >
    > One can hope.

    The emap when introduced wasn't really ready for hiking. I forget the
    limitations, but you can find posts on this newsgroup. The firmware
    upgrades added features, at least at first, but this is way too long ago
    for me to remember details.

    I keep the emap for a backup. At this point it isn't worth much on the
    used market, and I don't want to be far from a spare GPS should I be out
    in the boonies.

    I fired up the emap a few months ago. I forgot what a pleasure it was to
    have a black and white LCD. You can actually read those screens in
    daylight without having to hold it just right. Other than the stupid
    memory modules and lack of WAAS, it was a decent GPS. Put it in the
    rubber booty and it would lay flat on the dash. I really don't like the
    potato design of the GPSMAp60, though the performance is obviously
    better than the emap.

    Back to SDR, at some point DSP becomes cheaper than hardware. I'm not
    sure it ever becomes less power. Hardware is usually more reliable than
    software solutions.
     
    miso, Dec 11, 2011
    #10
  11. Sam Wormley

    macpacheco Guest

    On Dec 10, 11:09 pm, miso <> wrote:
    > On 12/10/2011 3:56 PM, macpacheco wrote:
    >
    >
    >
    >
    >
    >
    >
    > > On Dec 10, 8:47 pm, miso<>  wrote:
    > >> On 12/10/2011 1:40 PM, macpacheco wrote:

    >
    > >>> On Dec 10, 4:15 am, miso<>    wrote:
    > >>>> On 12/8/2011 1:14 PM, Alan Browne wrote:

    >
    > >>>>> On 2011-12-08 15:48 , macpacheco wrote:
    > >>>>>> On Dec 8, 2:32 pm, Sam Wormley<>    wrote:
    > >>>>>>> Beidou Launch Completes *Regional* Nav System

    >
    > >>>>>>>http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >
    > >>>>>>> December 6, 2011

    >
    > >>>>>>> "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    > >>>>>>> satellite was launched on December 1 from Xichang, China. Exact launch
    > >>>>>>> time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
    > >>>>>>> satellite attached achieved a geosynchronous transfer orbit and the
    > >>>>>>> satellite subsequently separated according to NORAD/JSpOC. As of
    > >>>>>>> December 7, the satellite is still in geosynchronous transfer orbit
    > >>>>>>> (GTO), orbiting the Earth about twice a day with a highly elipticorbit.
    > >>>>>>> To get to geosynchronous orbit, the satellite's apogee kick motorwill
    > >>>>>>> have to be fired. The satellite is not drifting to its intended orbit,
    > >>>>>>> for example, like a GLONASS satellite might".

    >
    > >>>>>>> See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >
    > >>>>>> Thanks Sam,

    >
    > >>>>>> The persistent question is where is the ICD !!!
    > >>>>>> Per the usual China stonewalls the open market every time it's to
    > >>>>>> their advantage.

    >
    > >>>>>http://www.insidegnss.com/node/1712

    >
    > >>>>>> Boycott Compass. Boycott China (to the largest extent possible).
    > >>>>>> We must make them hurts somehow, so they understand the only
    > >>>>>> acceptable behavior is to be open, democratic, and fair trading
    > >>>>>> practices.

    >
    > >>>>> The Chinese will never espouse fair trade, it is a one-way blanket pull.
    > >>>>> In the meantime avoid buying from them (you can't boycott 100% - they
    > >>>>> are into everything at the lowest cost and buyers around the world
    > >>>>> gravitate to low prices).

    >
    > >>>>> For satellite positioning the best thing is to wait until someone like
    > >>>>> Garmin makes a receiver with GPS+GLONASS+Galileo+Beidou-2.

    >
    > >>>>> Garmin for example (at least to present) make their receivers in Taiwan.

    >
    > >>>> I assume current generation of GPSs are heavily DSP if not SDR, but
    > >>>> often the more things you make a device do, the less it does well.
    > >>>> Smartphones are the perfect example. Jack of all trades, master of none.
    > >>>> Well a few brands have decent voice quality, so maybe master of one thing.

    >
    > >>> SDR don't make a lot of sense for circuitry planned to sell millions
    > >>> (if not tens of millions) units over the next few years.
    > >>> Specially for single frequency equipment that have no requirement for
    > >>> field upgrades.
    > >>> Besides companies like Garmin force customers to buy brand new units
    > >>> to get new features. When was the last time you saw a software upgrade
    > >>> for any Garmin handheld ? Products in the multi thousand dollar range
    > >>> do get some paid upgrades, but not<1000 USD products.
    > >>> SDRs are great for open flexible products and perhaps some low volume
    > >>> specialized receivers.
    > >>> In anything planned to ship millions of units bill of materials cost
    > >>> is paramount. The more functionality can be integrated into one large
    > >>> combo chip, the better.
    > >>> SDRs make sense for multi frequency, multi purpose stuff.

    >
    > >>> Marcelo Pacheco

    >
    > >> I flashed my emap more times that I can remember. I don't recall if I
    > >> ever flashed the GPSMap60.

    >
    > >> Incidentally, my Blackberry GPS claims 2 meter EPE. Reality, who knows..
    > >> It just bugs me to see people use smartphones as GPSs on the trails.
    > >> Depending on a phone gps is a bad idea. For one thing, slapping in a set
    > >> of AA cells isn't so simple. I have one of those AA to USB power
    > >> sources. Never even cracked open the plastic, but I carried it for a few
    > >> years for emergency purposes. When the EU forced all phones to go
    > >> microusb, I didn't bother to get another one.

    >
    > >> A friend was trying to locate some coordinates with her iphone. Easily
    > >> off 50ft. I gave her an old Lowrance.

    >
    > >> It used to be in the day if somebody gave you some coordinates, you
    > >> could trust them. Nowadays you have to ask what gear they used to get
    > >> the coordinates.

    >
    > > Did any of those re-flashing were for new functionality ? Bug fixes
    > > maybe. But new functionality, I think not...

    >
    > > All kinds of devices should be built with the physical equipment
    > > designed to at least 5 yrs, allowing the customer to upgrade to use
    > > new functionality often.

    >
    > > That's cheaper for the consumer, better for the environment, and might
    > > even be more profitable for the manufacturer.

    >
    > > 10 yrs ago this might not be possible, even 5 yrs ago might have been
    > > a challenge. But today with very powerful low power consumption CPUs
    > > and DSPs, it would make far more sense to do it that way.

    >
    > > One can hope.

    >
    > The emap when introduced wasn't really ready for hiking. I forget the
    > limitations, but you can find posts on this newsgroup. The firmware
    > upgrades added features, at least at first, but this is way too long ago
    > for me to remember details.
    >
    > I keep the emap for a backup. At this point it isn't worth much on the
    > used market, and I don't want to be far from a spare GPS should I be out
    > in the boonies.
    >
    > I fired up the emap a few months ago. I forgot what a pleasure it was to
    > have a black and white LCD. You can actually read those screens in
    > daylight without having to hold it just right. Other than the stupid
    > memory modules and lack of WAAS, it was a decent GPS. Put it in the
    > rubber booty and it would lay flat on the dash. I really don't like the
    > potato design of the GPSMAp60, though the performance is obviously
    > better than the emap.
    >
    > Back to SDR, at some point DSP becomes cheaper than hardware. I'm not
    > sure it ever becomes less power. Hardware is usually more reliable than
    > software solutions.


    Thinking aloud...

    A purpose built IC (ASIC) tends to use a lot less power than a DSP to
    perform the same task, as long as the ASIC is well designed. That's
    because ASICs work directly at the transistor level, while on the DSP,
    the application is software, that needs to be executed. An ASIC can
    easily do thousands of simple tasks in parallel, just add circuits to
    perform each needed task. DSPs excel when the application need to
    perform many tasks in series, one task feeds into the other, where in
    an ASIC a lot of transistors would have to be allocated to each task
    in an ASIC, but those transistors would be idle most of the time,
    waiting for other tasks to provide them with the needed input.

    And as long as those ASICs will be manufactured in large scale, they
    will also cost less than the equivalent DSP environment. Since ASICs
    perform functions in parallel, they don't require high clock (smaller
    gate size) manufacturing, allowing them to use older factories that
    are much cheaper than newer factories that produce smaller gate size
    circuits. Also because of their parallel nature, far lower power
    consumption is almost certain, since its usually possible to run the
    ASICs at a tiny fraction of the clock of a DSP. Power consumption is
    proportional to the clock squared. For instance, I think a GPS ASIC
    can run at 10MHz for L1 signal, and that's ten times the actual
    chipping rate for the L1 signal, while a DSP equivalent will need to
    run at GHz speeds, in order to track at least 18 channels and perform
    all correlation math for each channel keeping up with the signal flow.

    However, GPS receiver designs all have a CPU anyways, to run the user
    interface, draw maps, perform higher level calculations, ... Recently,
    low power CPUs achieve such high performance levels, that since a CPU
    is needed anyways, it actually costs less to move as much as possible
    of the work into the CPU (using a faster/more powerful CPU), keeping
    just the work that needs massively parallel logic (actual low level
    GPS receiver/correlators) in dedicated hardware, and everything else
    (from actually decoding the bits from the GPS signal into useful data
    and higher functions) all in the CPU. The simpler the ASIC, the
    cheaper it is to design it, it will mostly consist of dozens of copies
    of each logic, one for each channel. Fixing software is much cheaper
    than fixing hardware.

    For instance most dial up modems run DSP like logic on the host CPU
    (soft modems), and that has been happening for over 10 years, but a
    dial up modem only needs to worry about one signal, with a 8kHz
    sampling rate. Even the least powerful Intel CPU being sold today can
    handle such logic using less than 1% of their cycles. A GPS receiver
    needs to track and decode at least 12 channels @ 1MHz each, and the
    market is demanding 30+ channels for higher performance. And while the
    GPS signal is digital, its variable frequency due to doppler shift
    more than makes up for the easier "digital" versus "analog" reception.

    Marcelo Pacheco
     
    macpacheco, Dec 11, 2011
    #11
  12. Sam Wormley

    Alan Browne Guest

    On 2011-12-10 16:48 , macpacheco wrote:
    > On Dec 10, 12:47 pm, Alan Browne<>
    > wrote:
    >> On 2011-12-10 01:15 , miso wrote:
    >>
    >>
    >>
    >>
    >>
    >>
    >>
    >>
    >>
    >>> On 12/8/2011 1:14 PM, Alan Browne wrote:
    >>>> On 2011-12-08 15:48 , macpacheco wrote:
    >>>>> On Dec 8, 2:32 pm, Sam Wormley<> wrote:
    >>>>>> Beidou Launch Completes *Regional* Nav System

    >>
    >>>>>> http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >>
    >>>>>> December 6, 2011

    >>
    >>>>>> "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
    >>>>>> satellite was launched on December 1 from Xichang, China. Exact launch
    >>>>>> time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
    >>>>>> satellite attached achieved a geosynchronous transfer orbit and the
    >>>>>> satellite subsequently separated according to NORAD/JSpOC. As of
    >>>>>> December 7, the satellite is still in geosynchronous transfer orbit
    >>>>>> (GTO), orbiting the Earth about twice a day with a highly eliptic
    >>>>>> orbit.
    >>>>>> To get to geosynchronous orbit, the satellite's apogee kick motor will
    >>>>>> have to be fired. The satellite is not drifting to its intended orbit,
    >>>>>> for example, like a GLONASS satellite might".

    >>
    >>>>>> See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...

    >>
    >>>>> Thanks Sam,

    >>
    >>>>> The persistent question is where is the ICD !!!
    >>>>> Per the usual China stonewalls the open market every time it's to
    >>>>> their advantage.

    >>
    >>>> http://www.insidegnss.com/node/1712

    >>
    >>>>> Boycott Compass. Boycott China (to the largest extent possible).
    >>>>> We must make them hurts somehow, so they understand the only
    >>>>> acceptable behavior is to be open, democratic, and fair trading
    >>>>> practices.

    >>
    >>>> The Chinese will never espouse fair trade, it is a one-way blanket pull.
    >>>> In the meantime avoid buying from them (you can't boycott 100% - they
    >>>> are into everything at the lowest cost and buyers around the world
    >>>> gravitate to low prices).

    >>
    >>>> For satellite positioning the best thing is to wait until someone like
    >>>> Garmin makes a receiver with GPS+GLONASS+Galileo+Beidou-2.

    >>
    >>>> Garmin for example (at least to present) make their receivers in Taiwan.

    >>
    >>> I assume current generation of GPSs are heavily DSP if not SDR, but
    >>> often the more things you make a device do, the less it does well.
    >>> Smartphones are the perfect example. Jack of all trades, master of none.
    >>> Well a few brands have decent voice quality, so maybe master of one thing.

    >>
    >> GPS's use dedicated hardware correlator channels driven by software to
    >> detect and track the signal. It is relatively cheap and easy to add
    >> channels although those for GPS are different than those for GLONASS and
    >> will also be different for Galileo and Compass. Some GPS receivers that
    >> cost a few dollars (in bulk) have about 60 channels. When future civil
    >> channels are added they will require more hardware channels as well.
    >>
    >> They are cheap and are not usually DSP|SDR (it's just not the cheapest
    >> way to go, esp. for low power consumption devices).
    >>
    >> So, you can indeed have "more" and not lose anything at all. The
    >> question then becomes optimizing the algorithms to truly get the best
    >> information for position determination.
    >>
    >> In GPS it's called "over determination". But unless craftily
    >> implemented, using all sources for a position fix could lead to a
    >> greater error when the worst satellite PR's are used with the best. An
    >> example is mixing GPS with GLONASS (the later being a little less
    >> accurate than GPS at present).
    >>
    >> Smartphones that I know of use very low power GPS devices and are also
    >> driven "lazily" to conserve power. That aside, the performance of my
    >> iPhone 4 as a GPS is more than adequate for what it was designed to do
    >> (get me to the restaurant). In comparing with dedicated GPS', it has an
    >> error range of about 5-20 metres where the dedicated GPS is 3-5 metres
    >> in the same conditions. The newer iPhone 4S also has GLONASS so
    >> presumably acquires quicker, but if driven lazily, is probably not more
    >> accurate than the iPhone 4.
    >>
    >> --
    >> "I see!" said the blind man as he picked up his hammer and saw.

    >
    > Interesting your statement that GLONASS accuracy is lower than GPS.
    > I'm not trying to pick a fight, just to raise the fact that PDOP
    > charts for GLONASS actually look better than those for GPS.


    Don't recall where but there is a chart presented recently by the
    GLONASS office showing increasing accuracy but still clearly not as
    accurate as GPS - the difference is not big, but it is clear. The
    difference is getting narrower by the year as they improve operational
    control (I guess this includes the quality of the measurements in space
    of where the sats are, data processing and upload of the nav data).



    --
    "I see!" said the blind man as he picked up his hammer and saw.
     
    Alan Browne, Dec 11, 2011
    #12
  13. Sam Wormley

    Alan Browne Guest

    On 2011-12-10 17:47 , miso wrote:
    > On 12/10/2011 1:40 PM, macpacheco wrote:
    >> On Dec 10, 4:15 am, miso<> wrote:
    >>> On 12/8/2011 1:14 PM, Alan Browne wrote:
    >>>
    >>>
    >>>
    >>>
    >>>
    >>>
    >>>
    >>>
    >>>
    >>>> On 2011-12-08 15:48 , macpacheco wrote:
    >>>>> On Dec 8, 2:32 pm, Sam Wormley<> wrote:
    >>>>>> Beidou Launch Completes *Regional* Nav System
    >>>
    >>>>>> http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...
    >>>>>>
    >>>>>>
    >>>
    >>>>>> December 6, 2011
    >>>
    >>>>>> "The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous
    >>>>>> orbit) satellite was launched on December 1 from Xichang,
    >>>>>> China. Exact launch time was 21:07:04.189 UTC. The third
    >>>>>> stage of the CZ-3A rocket with the satellite attached
    >>>>>> achieved a geosynchronous transfer orbit and the satellite
    >>>>>> subsequently separated according to NORAD/JSpOC. As of
    >>>>>> December 7, the satellite is still in geosynchronous
    >>>>>> transfer orbit (GTO), orbiting the Earth about twice a day
    >>>>>> with a highly eliptic orbit. To get to geosynchronous
    >>>>>> orbit, the satellite's apogee kick motor will have to be
    >>>>>> fired. The satellite is not drifting to its intended
    >>>>>> orbit, for example, like a GLONASS satellite might".
    >>>
    >>>>>> See:http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regi...
    >>>>>>
    >>>>>>
    >>>
    >>>>> Thanks Sam,
    >>>
    >>>>> The persistent question is where is the ICD !!! Per the usual
    >>>>> China stonewalls the open market every time it's to their
    >>>>> advantage.
    >>>
    >>>> http://www.insidegnss.com/node/1712
    >>>
    >>>>> Boycott Compass. Boycott China (to the largest extent
    >>>>> possible). We must make them hurts somehow, so they
    >>>>> understand the only acceptable behavior is to be open,
    >>>>> democratic, and fair trading practices.
    >>>
    >>>> The Chinese will never espouse fair trade, it is a one-way
    >>>> blanket pull. In the meantime avoid buying from them (you can't
    >>>> boycott 100% - they are into everything at the lowest cost and
    >>>> buyers around the world gravitate to low prices).
    >>>
    >>>> For satellite positioning the best thing is to wait until
    >>>> someone like Garmin makes a receiver with
    >>>> GPS+GLONASS+Galileo+Beidou-2.
    >>>
    >>>> Garmin for example (at least to present) make their receivers
    >>>> in Taiwan.
    >>>
    >>> I assume current generation of GPSs are heavily DSP if not SDR,
    >>> but often the more things you make a device do, the less it does
    >>> well. Smartphones are the perfect example. Jack of all trades,
    >>> master of none. Well a few brands have decent voice quality, so
    >>> maybe master of one thing.

    >>
    >> SDR don't make a lot of sense for circuitry planned to sell
    >> millions (if not tens of millions) units over the next few years.
    >> Specially for single frequency equipment that have no requirement
    >> for field upgrades. Besides companies like Garmin force customers
    >> to buy brand new units to get new features. When was the last time
    >> you saw a software upgrade for any Garmin handheld ? Products in
    >> the multi thousand dollar range do get some paid upgrades, but
    >> not<1000 USD products. SDRs are great for open flexible products
    >> and perhaps some low volume specialized receivers. In anything
    >> planned to ship millions of units bill of materials cost is
    >> paramount. The more functionality can be integrated into one large
    >> combo chip, the better. SDRs make sense for multi frequency, multi
    >> purpose stuff.
    >>
    >> Marcelo Pacheco

    >
    > I flashed my emap more times that I can remember. I don't recall if I
    > ever flashed the GPSMap60.
    >
    > Incidentally, my Blackberry GPS claims 2 meter EPE. Reality, who
    > knows. It just bugs me to see people use smartphones as GPSs on the
    > trails.


    I have 2 Apps on my iPhone that are pretty decent on the trails - but
    the battery life and lack of charger make it a poor device to use. The
    accuracy of the iPhone GPS is poor (below).

    > Depending on a phone gps is a bad idea. For one thing, slapping in a
    > set of AA cells isn't so simple. I have one of those AA to USB power
    > sources. Never even cracked open the plastic, but I carried it for a
    > few years for emergency purposes. When the EU forced all phones to go
    > microusb, I didn't bother to get another one.


    You can get power extenders for the iPHone (battery that plugs into the
    base), but that's clumsy at best.

    > A friend was trying to locate some coordinates with her iphone.
    > Easily off 50ft. I gave her an old Lowrance.


    I made a lot of recordings with the iPhone v. a dedicates GPS.
    Comparing on ground truths, the GPS achieves less than 5 metres most of
    the time in open sky areas. The iphone is 5 - 20 metres.

    The iPhone is great for getting to the right restaurant in a jiff, but
    really a jack of all trades for dedicated car or trail navigation.

    --
    "I see!" said the blind man as he picked up his hammer and saw.
     
    Alan Browne, Dec 11, 2011
    #13
  14. Sam Wormley

    Alan Browne Guest

    On 2011-12-10 20:09 , miso wrote:

    > Back to SDR, at some point DSP becomes cheaper than hardware. I'm not
    > sure it ever becomes less power. Hardware is usually more reliable than
    > software solutions.


    For something like GPS where (as macp.. pointed out) the frequencies are
    the same, the de-mod the same, and so on over the course of the life of
    the receiver, SDR is plain overkill. Further it is a power intensive
    approach to signal processing v. hardware based correlators which are
    the antithesis of general purpose - they can be made hardware lean and
    use less power. The more so when the sampling circuitry is on the same
    chip as the correlators. Short, efficient path.

    In SDR the processor is more general purpose and so less power efficient
    for the specific purpose. On the other hand, SDR is more system and
    life cycle efficient - lower component counts and logistics issues for
    complex radios that evolve over time.

    --
    "I see!" said the blind man as he picked up his hammer and saw.
     
    Alan Browne, Dec 11, 2011
    #14
  15. Sam Wormley

    Alan Browne Guest

    On 2011-12-10 20:09 , miso wrote:

    > Back to SDR, at some point DSP becomes cheaper than hardware. I'm not
    > sure it ever becomes less power. Hardware is usually more reliable than
    > software solutions.


    BTW: https://github.com/gps-sdr

    Seems to be a collaborative open-source project.

    Not clear to me what front end hardware is used for the signal.

    The file gps-sdr / usrp / fpga_regs_standard.h
    defines access to an FPGA of some sort which would be the GPS front end
    (let's assume a device to read the A/D. Seems to be 4 sampling
    channels with phase).

    I'd guess one could implement this on pretty much any CPU under the
    appropriate RTOS (or standalone(??)).

    I doubt the above would be energy efficient v. a dedicated GPS chipset.

    --
    "I see!" said the blind man as he picked up his hammer and saw.
     
    Alan Browne, Dec 11, 2011
    #15
  16. Sam Wormley

    Alan Browne Guest

    Re: Beidou Launch Completes Regional Nav System - HW

    On 2011-12-11 10:19 , Alan Browne wrote:
    > On 2011-12-10 20:09 , miso wrote:
    >
    >> Back to SDR, at some point DSP becomes cheaper than hardware. I'm not
    >> sure it ever becomes less power. Hardware is usually more reliable than
    >> software solutions.

    >
    > BTW: https://github.com/gps-sdr
    >
    > Seems to be a collaborative open-source project.
    >
    > Not clear to me what front end hardware is used for the signal.
    >
    > The file gps-sdr / usrp / fpga_regs_standard.h
    > defines access to an FPGA of some sort which would be the GPS front end
    > (let's assume a device to read the A/D. Seems to be 4 sampling channels
    > with phase).
    >
    > I'd guess one could implement this on pretty much any CPU under the
    > appropriate RTOS (or standalone(??)).
    >
    > I doubt the above would be energy efficient v. a dedicated GPS chipset.


    Here's the hardware they use to sample the signal:

    http://www.sparkfun.com/products/8238

    http://www.ettus.com/products




    --
    "I see!" said the blind man as he picked up his hammer and saw.
     
    Alan Browne, Dec 11, 2011
    #16
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