Re: GPS for Nikon

Discussion in 'Digital Photography' started by nospam, Apr 28, 2013.

  1. nospam

    nospam Guest

    In article <klj0ak$r93$>, Me <>
    wrote:

    > > I use the Nikon GP-1 with my D300S. If my camera has been turned off for
    > > any considerable time, the GP-1 takes between 45 seconds to two minutes
    > > to obtain initial Sat acquisition. Once that is done and I am outdoors I
    > > leave the camera on, and the additional battery drainage is negligible.
    > > However I am using the Nikon MB-D10 grip + EN-EL4 battery.
    > >
    > > After initial acquisition it performs well, even when briefly having
    > > clear sky obscured by a tent, marquee, or tree cover. However heavy tree
    > > cover can, and has interrupted the signal causing a failure to record
    > > the data.

    >
    > This is nuts. My android phone has a GPS that takes a fraction of that
    > time to acquire a fix (satellite only), heavy tree cover not a problem.


    smartphones use the cellular network to speed up the time to get a fix
    and handle situations where gps reception is weak, such as under heavy
    tree cover.

    if cameras had cellular phones in them, they could do that too.

    > It also outperforms (signal strength/processing grunt) my in-car GPS and
    > my lowrance marine GPS by a mile (each of which cost much more than the
    > phone).


    doubtful.

    > Qualcomm etc make "combo" GPS/bluetooth/wifi chipsets for phones. They
    > must be cheap - my phone (no plan) was very inexpensive.
    > DSLR makers should dump proprietary firmware/OS.


    that's a separate issue.
     
    nospam, Apr 28, 2013
    #1
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  2. nospam

    nospam Guest

    In article <>, Alan Browne
    <> wrote:

    > >> It also outperforms (signal strength/processing grunt) my in-car GPS and
    > >> my lowrance marine GPS by a mile (each of which cost much more than the
    > >> phone).

    > >
    > >doubtful.

    >
    > It depends what he means by "outperform". If it means faster
    > acquisition, he's right - but he'll have no idea how bad the quality of
    > the solution is.


    he said signal strength/processing grunt, whatever that means.

    a smartphone might have a more capable processor (how many dedicated
    gps units have a multicore cpu and gpu?), but that just makes for
    pretty graphics and a responsive interface.

    it says nothing about the radio, which is what matters.

    > A marine GPS (like aviation) should be conservative. That results in
    > slower acquisition, but better certainty about the quality of the
    > solution. Since marine units operate in areas without much obstruction
    > to the sky (typically) a conservative acquisition/tracking threshold is
    > a good idea. Some marine units also allow you to enter the altitude of
    > the surface you are on (lake elevation for example) and that gives you a
    > "free" virtual satellite located at the center of the earth.
    >
    > (Indeed, if the altitude setting is used, but incorrect by a good bit,
    > it will drag the position solution with it a good way unless RAIM is
    > used to discard it. I don't believe any marine units use RAIM however).
    >
    > I don't have much of an opinion on automobile GPS sets. They seem to do
    > well, but will occasionally show a wild error (show position on a
    > parallel street 2 blocks away; or on the service road, etc.).
    >
    > Mine seems to use the map for position aiding. When I drive off road at
    > an angle, the position will show as on the road until I'm about 100m off
    > of the road.


    i've never seen a 2 block error in a car, but have seen it lock to the
    frontage road right next to the highway or vice versa. it's rarely an
    issue since it's obvious what it should be and it quickly corrects
    itself anyway.
     
    nospam, Apr 28, 2013
    #2
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  3. nospam

    Me Guest

    On 29/04/2013 2:42 a.m., Alan Browne wrote:
    > On 2013.04.28 10:04 , nospam wrote:
    >> In article <klj0ak$r93$>, Me <>
    >> wrote:
    >>
    >>>> I use the Nikon GP-1 with my D300S. If my camera has been turned off
    >>>> for
    >>>> any considerable time, the GP-1 takes between 45 seconds to two minutes
    >>>> to obtain initial Sat acquisition. Once that is done and I am
    >>>> outdoors I
    >>>> leave the camera on, and the additional battery drainage is negligible.
    >>>> However I am using the Nikon MB-D10 grip + EN-EL4 battery.
    >>>>
    >>>> After initial acquisition it performs well, even when briefly having
    >>>> clear sky obscured by a tent, marquee, or tree cover. However heavy
    >>>> tree
    >>>> cover can, and has interrupted the signal causing a failure to record
    >>>> the data.
    >>>
    >>> This is nuts. My android phone has a GPS that takes a fraction of that
    >>> time to acquire a fix (satellite only), heavy tree cover not a problem.

    >>
    >> smartphones use the cellular network to speed up the time to get a fix
    >> and handle situations where gps reception is weak, such as under heavy
    >> tree cover.

    As I said, satellite only. Using cell tower "Google location service"
    can be disabled, and in any case, either in my boat or in my car, I'm
    frequently in places where there's no cellular service and no wifi, no
    data service.
    Sure - if using cell/wifi location services is enabled and within range,
    then initial location fix is effectively instant (fix acquired by the
    time the app is up and running), but with satellite only the phone is
    much faster acquiring a new position fix than either dedicated GPS unit.
    The new chipsets for phones are also combined glonass/gps receivers =
    more satellites than gps alone.
    >>
    >> if cameras had cellular phones in them, they could do that too.
    >>
    >>> It also outperforms (signal strength/processing grunt) my in-car GPS and
    >>> my lowrance marine GPS by a mile (each of which cost much more than the
    >>> phone).

    >>
    >> doubtful.

    >
    > It depends what he means by "outperform". If it means faster
    > acquisition, he's right - but he'll have no idea how bad the quality of
    > the solution is.
    >

    How's that? If I can use two devices side by side, then surely that's a
    pretty good indication. If the "quality of the solution" is
    self-reported accuracy, then I can't see any difference. If it's
    positional accuracy when zoomed in to a base map on a chart plotter,
    then I can't see any difference either.
    So I walk outside with my GPS phone on to my deck, zoom in with a google
    satellite overlay, and it shows that I'm on the deck of my house,
    reported accuracy 4m - but I presume that's maximum deviation, as it's
    pinpointed my position within a metre.
    But the phone outperforms each dedicated device in other ways. Battery
    use is much lower, map loading is much faster, screen resolution is
    higher with much faster refresh/scrolling, route calculation (using a
    dedicated "off-line" car GPS app) is much faster.
    >
    > A marine GPS (like aviation) should be conservative. That results in
    > slower acquisition, but better certainty about the quality of the
    > solution. Since marine units operate in areas without much obstruction
    > to the sky (typically) a conservative acquisition/tracking threshold is
    > a good idea. Some marine units also allow you to enter the altitude of
    > the surface you are on (lake elevation for example) and that gives you a
    > "free" virtual satellite located at the center of the earth.
    >
    > (Indeed, if the altitude setting is used, but incorrect by a good bit,
    > it will drag the position solution with it a good way unless RAIM is
    > used to discard it. I don't believe any marine units use RAIM however).
    >

    I'm deeply suspicious that this is derived from marketing-speak/FUD
    originating from dedicated GPS vendors.
    For free, you can d/l the complete and official set of NZ and South
    Pacific marine charts from the source, raster format, and use them on a
    phone or tablet. GPS vendors used to bleed customers dry on prices for
    the same maps formatted to work on their proprietary systems. Same for
    the entire set of NZ topo maps. The apps I've looked at are a little
    rough around the edges, but GPS accuracy and the maps themselves are not
    the weak point.
    I don't expect to see a commercial pilot or ship captain using a $US100
    phone to navigate by, but I don't see any reason why an expensive
    dedicated GPS unit needs to be used to geotag photos.
    >
    > I don't have much of an opinion on automobile GPS sets. They seem to do
    > well, but will occasionally show a wild error (show position on a
    > parallel street 2 blocks away; or on the service road, etc.).
    >
    > Mine seems to use the map for position aiding. When I drive off road at
    > an angle, the position will show as on the road until I'm about 100m off
    > of the road.
    >
     
    Me, Apr 28, 2013
    #3
  4. nospam

    Me Guest

    On 29/04/2013 10:51 a.m., Alan Browne wrote:

    >
    > The thing there is that it's based on "satellites in view" rather than
    > satellites actually being received and tracked. "in view" means "from
    > where you are, if there were no obsacles..."
    >

    No. There's even a free android app "GPS essentials" which gives a
    graphic positional chart, showing satellites that are in view, and of
    those, which are in view which ones are used for tracking, and a
    graphical representation of s/n ratio for each.
    >
    >> So I walk outside with my GPS phone on to my deck, zoom in with a google
    >> satellite overlay, and it shows that I'm on the deck of my house,
    >> reported accuracy 4m - but I presume that's maximum deviation, as it's
    >> pinpointed my position within a metre.

    >
    > I can show you Google satellite views that are off by over 10 metres -
    > without even referencing a GPS. Take it with a grain of salt. That
    > said, Google sat views are very good - but not always, dependably so.

    I'd like to know how systems like Google Earth allow for tectonic plate
    movement.
    >
    >> But the phone outperforms each dedicated device in other ways. Battery
    >> use is much lower, map loading is much faster, screen resolution is
    >> higher with much faster refresh/scrolling, route calculation (using a
    >> dedicated "off-line" car GPS app) is much faster.

    >
    > I plot WAAS GPS' v. the iPhone and the iPhone error is usually 5-20
    > metres v. true all-in-view/WAAS errors of 3 - 5 metres.
    >
    > The iPhone GPS saves power by driving the correlators less often.
    > (Typical is 1 Hz, some GPS' go 10 or 20 or more. The iPhone is 0.5 Hz
    > or worse).
    >

    I'm not using an iPhone. GPS update interval is user-adjustable.
    >
    > Shipboard GPS systems are integrated with plotters and the radar system,
    > position reporting, autopilot and so on. It's very sophisticated and in
    > someways laughably badly done - esp. the communications bus (bogged down
    > by legacy crap).
    >

    Yes - I was on a suction dredger a few weeks ago, made my way out on the
    harbour pilot boat, accompanied by a tech from a marine instrument
    company who was going to service some of their systems.
    The systems were complex, I believe integrating sonar depth plotting -
    the dredge head must be positioned accurately, taking into account tide
    and the hopper load as they fill it. If they get it wrong, something
    very expensive gets broken.
     
    Me, Apr 29, 2013
    #4
  5. nospam

    PeterN Guest

    On 4/28/2013 11:19 AM, nospam wrote:
    > In article <>, Alan Browne
    > <> wrote:
    >
    >>>> It also outperforms (signal strength/processing grunt) my in-car GPS and
    >>>> my lowrance marine GPS by a mile (each of which cost much more than the
    >>>> phone).
    >>>
    >>> doubtful.

    >>
    >> It depends what he means by "outperform". If it means faster
    >> acquisition, he's right - but he'll have no idea how bad the quality of
    >> the solution is.

    >
    > he said signal strength/processing grunt, whatever that means.
    >
    > a smartphone might have a more capable processor (how many dedicated
    > gps units have a multicore cpu and gpu?), but that just makes for
    > pretty graphics and a responsive interface.
    >
    > it says nothing about the radio, which is what matters.
    >
    >> A marine GPS (like aviation) should be conservative. That results in
    >> slower acquisition, but better certainty about the quality of the
    >> solution. Since marine units operate in areas without much obstruction
    >> to the sky (typically) a conservative acquisition/tracking threshold is
    >> a good idea. Some marine units also allow you to enter the altitude of
    >> the surface you are on (lake elevation for example) and that gives you a
    >> "free" virtual satellite located at the center of the earth.
    >>
    >> (Indeed, if the altitude setting is used, but incorrect by a good bit,
    >> it will drag the position solution with it a good way unless RAIM is
    >> used to discard it. I don't believe any marine units use RAIM however).
    >>
    >> I don't have much of an opinion on automobile GPS sets. They seem to do
    >> well, but will occasionally show a wild error (show position on a
    >> parallel street 2 blocks away; or on the service road, etc.).
    >>
    >> Mine seems to use the map for position aiding. When I drive off road at
    >> an angle, the position will show as on the road until I'm about 100m off
    >> of the road.

    >
    > i've never seen a 2 block error in a car, but have seen it lock to the
    > frontage road right next to the highway or vice versa. it's rarely an
    > issue since it's obvious what it should be and it quickly corrects
    > itself anyway.
    >


    You would have if you were using my Garmin today. It told me to make a
    turn just after I passed the exit. Despite claims to the contrary, I am
    not convinced that selective Availability has been turned off.


    --
    PeterN
     
    PeterN, Apr 30, 2013
    #5
  6. nospam

    nospam Guest

    In article <51804a04$0$10832$-secrets.com>, PeterN
    <> wrote:

    > >> I don't have much of an opinion on automobile GPS sets. They seem to do
    > >> well, but will occasionally show a wild error (show position on a
    > >> parallel street 2 blocks away; or on the service road, etc.).
    > >>
    > >> Mine seems to use the map for position aiding. When I drive off road at
    > >> an angle, the position will show as on the road until I'm about 100m off
    > >> of the road.

    > >
    > > i've never seen a 2 block error in a car, but have seen it lock to the
    > > frontage road right next to the highway or vice versa. it's rarely an
    > > issue since it's obvious what it should be and it quickly corrects
    > > itself anyway.

    >
    > You would have if you were using my Garmin today. It told me to make a
    > turn just after I passed the exit.


    missing an exit is not a 2 block error.

    > Despite claims to the contrary, I am
    > not convinced that selective Availability has been turned off.


    it definitely has. anyone who thinks otherwise is confused.
     
    nospam, May 1, 2013
    #6
  7. nospam

    PeterN Guest

    On 4/30/2013 8:30 PM, nospam wrote:
    > In article <51804a04$0$10832$-secrets.com>, PeterN
    > <> wrote:
    >
    >>>> I don't have much of an opinion on automobile GPS sets. They seem to do
    >>>> well, but will occasionally show a wild error (show position on a
    >>>> parallel street 2 blocks away; or on the service road, etc.).
    >>>>
    >>>> Mine seems to use the map for position aiding. When I drive off road at
    >>>> an angle, the position will show as on the road until I'm about 100m off
    >>>> of the road.
    >>>
    >>> i've never seen a 2 block error in a car, but have seen it lock to the
    >>> frontage road right next to the highway or vice versa. it's rarely an
    >>> issue since it's obvious what it should be and it quickly corrects
    >>> itself anyway.

    >>
    >> You would have if you were using my Garmin today. It told me to make a
    >> turn just after I passed the exit.

    >
    > missing an exit is not a 2 block error.


    Correct. It can be many miles.

    My guess is that you do not use a GPS very often. The one in my iPhone
    has Wakodahatchee in DelRay Beach, FL., about three blocks east of its
    location. My iPhone GPS insisted that I drive through a swamp to get to
    Zoo Miami. You don't have to believe me, look it up for yourself.


    >
    >> Despite claims to the contrary, I am
    >> not convinced that selective Availability has been turned off.

    >
    > it definitely has. anyone who thinks otherwise is confused.
    >


    I find your reassurance comforting.

    --
    PeterN
     
    PeterN, May 1, 2013
    #7
  8. nospam

    nospam Guest

    In article <51806b68$0$10781$-secrets.com>, PeterN
    <> wrote:

    > >>>> I don't have much of an opinion on automobile GPS sets. They seem to do
    > >>>> well, but will occasionally show a wild error (show position on a
    > >>>> parallel street 2 blocks away; or on the service road, etc.).
    > >>>>
    > >>>> Mine seems to use the map for position aiding. When I drive off road at
    > >>>> an angle, the position will show as on the road until I'm about 100m off
    > >>>> of the road.
    > >>>
    > >>> i've never seen a 2 block error in a car, but have seen it lock to the
    > >>> frontage road right next to the highway or vice versa. it's rarely an
    > >>> issue since it's obvious what it should be and it quickly corrects
    > >>> itself anyway.
    > >>
    > >> You would have if you were using my Garmin today. It told me to make a
    > >> turn just after I passed the exit.

    > >
    > > missing an exit is not a 2 block error.

    >
    > Correct. It can be many miles.


    you're so full of shit.

    if you have a gps fix, it's definitely not off by 'many miles.'

    if you don't have a gps fix, then your position can be anywhere. that's
    what not having a gps fix means. wait until you actually do get a fix
    before departing (plus, it takes longer to get a fix while moving too).

    > My guess is that you do not use a GPS very often.


    then you'd be wrong.

    i often use a gps even when i know where i'm going because it knows
    about traffic and also has an estimated time of arrival and has a more
    accurate display of my current speed and distance travelled.

    for road trips, i always use one.

    > The one in my iPhone
    > has Wakodahatchee in DelRay Beach, FL., about three blocks east of its
    > location. My iPhone GPS insisted that I drive through a swamp to get to
    > Zoo Miami. You don't have to believe me, look it up for yourself.


    that's a map error, not a gps error.

    in addition to apple's and google's maps, there are at least 7 gps apps
    for the iphone that i can think of (navigon, tomtom, magellan, garmin,
    copilot, motionx, waze), each of which has its own idea about what
    roads are where and how to best route on them.

    if one of those apps tells you to drive through a swamp then either
    report the map error or switch to a different app (or both).

    i also notice that you've switched from the garmin missed exit to the
    iphone. what were you saying about bullshitting your way out?

    > >> Despite claims to the contrary, I am
    > >> not convinced that selective Availability has been turned off.

    > >
    > > it definitely has. anyone who thinks otherwise is confused.

    >
    > I find your reassurance comforting.


    s/a was turned off may, 2000.

    this is a fact that anyone can confirm.

    it's without question, off.
     
    nospam, May 1, 2013
    #8
  9. nospam

    PeterN Guest

    On 4/30/2013 10:02 PM, nospam wrote:
    > In article <51806b68$0$10781$-secrets.com>, PeterN
    > <> wrote:
    >
    >>>>>> I don't have much of an opinion on automobile GPS sets. They seem to do
    >>>>>> well, but will occasionally show a wild error (show position on a
    >>>>>> parallel street 2 blocks away; or on the service road, etc.).
    >>>>>>
    >>>>>> Mine seems to use the map for position aiding. When I drive off road at
    >>>>>> an angle, the position will show as on the road until I'm about 100m off
    >>>>>> of the road.
    >>>>>
    >>>>> i've never seen a 2 block error in a car, but have seen it lock to the
    >>>>> frontage road right next to the highway or vice versa. it's rarely an
    >>>>> issue since it's obvious what it should be and it quickly corrects
    >>>>> itself anyway.
    >>>>
    >>>> You would have if you were using my Garmin today. It told me to make a
    >>>> turn just after I passed the exit.
    >>>
    >>> missing an exit is not a 2 block error.

    >>
    >> Correct. It can be many miles.

    >
    > you're so full of shit.


    Whoosh!

    >
    > if you have a gps fix, it's definitely not off by 'many miles.'
    >
    > if you don't have a gps fix, then your position can be anywhere. that's
    > what not having a gps fix means. wait until you actually do get a fix
    > before departing (plus, it takes longer to get a fix while moving too).




    If the unit causes me to miss my exit, it still can take many mile to
    recover. that is, unless you are one of those assholes who backs up on
    an Interstate.


    >
    >> My guess is that you do not use a GPS very often.

    >
    > then you'd be wrong.
    >
    > i often use a gps even when i know where i'm going because it knows
    > about traffic and also has an estimated time of arrival and has a more
    > accurate display of my current speed and distance travelled.


    Sounds important to me!

    >
    > for road trips, i always use one.
    >


    You must have a very good and intuitive system.
    And I truly believe that someone with your intelligence would completely
    rely on one, especially when you know the route.


    >> The one in my iPhone
    >> has Wakodahatchee in DelRay Beach, FL., about three blocks east of its
    >> location. My iPhone GPS insisted that I drive through a swamp to get to
    >> Zoo Miami. You don't have to believe me, look it up for yourself.

    >
    > that's a map error, not a gps error.
    >
    > in addition to apple's and google's maps, there are at least 7 gps apps
    > for the iphone that i can think of (navigon, tomtom, magellan, garmin,
    > copilot, motionx, waze), each of which has its own idea about what
    > roads are where and how to best route on them.


    Gee. I hadn't thought of that... What a great idea. If my ability to
    find my desired location is impaired, just try another. Do I do so while
    driving, or stop on a busy road, hoping I will get one of the lucky seven.


    >
    > if one of those apps tells you to drive through a swamp then either
    > report the map error or switch to a different app (or both).
    >
    > i also notice that you've switched from the garmin missed exit to the
    > iphone. what were you saying about bullshitting your way out?


    Gee you are observant. If only you had comprehensive ability. But that
    would be expecting too much.


    >
    >>>> Despite claims to the contrary, I am
    >>>> not convinced that selective Availability has been turned off.
    >>>
    >>> it definitely has. anyone who thinks otherwise is confused.

    >>
    >> I find your reassurance comforting.

    >
    > s/a was turned off may, 2000.
    >
    > this is a fact that anyone can confirm.
    >
    > it's without question, off.
    >


    Yup!

    --
    PeterN
     
    PeterN, May 1, 2013
    #9
  10. nospam

    nospam Guest

    In article <5181312a$0$10806$-secrets.com>, PeterN
    <> wrote:

    > > if you have a gps fix, it's definitely not off by 'many miles.'
    > >
    > > if you don't have a gps fix, then your position can be anywhere. that's
    > > what not having a gps fix means. wait until you actually do get a fix
    > > before departing (plus, it takes longer to get a fix while moving too).

    >
    > If the unit causes me to miss my exit, it still can take many mile to
    > recover. that is, unless you are one of those assholes who backs up on
    > an Interstate.


    that's not the fault of the gps. that's you not paying attention.

    a gps will give ample warning before an upcoming turn or exit and then
    again closer to the actual turn. if you miss the exit, it's your fault.

    hopefully, you don't endanger others in the process.

    > >> My guess is that you do not use a GPS very often.

    > >
    > > then you'd be wrong.
    > >
    > > i often use a gps even when i know where i'm going because it knows
    > > about traffic and also has an estimated time of arrival and has a more
    > > accurate display of my current speed and distance travelled.

    >
    > Sounds important to me!


    knowing about traffic is very important as is knowing exact speed,
    unless you like getting tickets. car speedometers are not very
    accurate.

    > > for road trips, i always use one.

    >
    > You must have a very good and intuitive system.


    i do.

    > And I truly believe that someone with your intelligence would completely
    > rely on one, especially when you know the route.


    i don't rely on a gps at all. i *use* a gps as a navigational aid.

    anyone who blindly follows a gps without using their brain deserves
    what they get. expecting a gps to give perfect directions in all
    situations is just asking for trouble.

    that's how stuff like this happens:
    <http://abcnews.go.com/blogs/headlines/2012/03/gps-tracking-disaster-jap
    anese-tourists-drive-straight-into-the-pacific/>

    <http://abcnews.go.com/Technology/gps-mishaps-trust-tech-leads-trouble/s
    tory?id=10013723>

    > >> The one in my iPhone
    > >> has Wakodahatchee in DelRay Beach, FL., about three blocks east of its
    > >> location. My iPhone GPS insisted that I drive through a swamp to get to
    > >> Zoo Miami. You don't have to believe me, look it up for yourself.

    > >
    > > that's a map error, not a gps error.
    > >
    > > in addition to apple's and google's maps, there are at least 7 gps apps
    > > for the iphone that i can think of (navigon, tomtom, magellan, garmin,
    > > copilot, motionx, waze), each of which has its own idea about what
    > > roads are where and how to best route on them.

    >
    > Gee. I hadn't thought of that...


    now you do.

    > What a great idea. If my ability to
    > find my desired location is impaired, just try another. Do I do so while
    > driving, or stop on a busy road, hoping I will get one of the lucky seven.


    if you can't figure that out, then you deserve to get stuck in a swamp.

    > > if one of those apps tells you to drive through a swamp then either
    > > report the map error or switch to a different app (or both).
    > >
    > > i also notice that you've switched from the garmin missed exit to the
    > > iphone. what were you saying about bullshitting your way out?

    >
    > Gee you are observant. If only you had comprehensive ability. But that
    > would be expecting too much.


    the only thing to expect are moronic insults from you.

    > >>>> Despite claims to the contrary, I am
    > >>>> not convinced that selective Availability has been turned off.
    > >>>
    > >>> it definitely has. anyone who thinks otherwise is confused.
    > >>
    > >> I find your reassurance comforting.

    > >
    > > s/a was turned off may, 2000.
    > >
    > > this is a fact that anyone can confirm.
    > >
    > > it's without question, off.

    >
    > Yup!


    in other words, you admit you were lying.
     
    nospam, May 1, 2013
    #10
  11. nospam

    PeterN Guest

    On 5/1/2013 2:25 PM, nospam wrote:
    > In article <5181312a$0$10806$-secrets.com>, PeterN
    > <> wrote:
    >
    >>> if you have a gps fix, it's definitely not off by 'many miles.'
    >>>
    >>> if you don't have a gps fix, then your position can be anywhere. that's
    >>> what not having a gps fix means. wait until you actually do get a fix
    >>> before departing (plus, it takes longer to get a fix while moving too).

    >>
    >> If the unit causes me to miss my exit, it still can take many mile to
    >> recover. that is, unless you are one of those assholes who backs up on
    >> an Interstate.

    >
    > that's not the fault of the gps. that's you not paying attention.
    >
    > a gps will give ample warning before an upcoming turn or exit and then
    > again closer to the actual turn. if you miss the exit, it's your fault.
    >
    > hopefully, you don't endanger others in the process.
    >
    >>>> My guess is that you do not use a GPS very often.
    >>>
    >>> then you'd be wrong.
    >>>
    >>> i often use a gps even when i know where i'm going because it knows
    >>> about traffic and also has an estimated time of arrival and has a more
    >>> accurate display of my current speed and distance travelled.

    >>
    >> Sounds important to me!

    >
    > knowing about traffic is very important as is knowing exact speed,
    > unless you like getting tickets. car speedometers are not very
    > accurate.
    >
    >>> for road trips, i always use one.

    >>
    >> You must have a very good and intuitive system.

    >
    > i do.
    >
    >> And I truly believe that someone with your intelligence would completely
    >> rely on one, especially when you know the route.

    >
    > i don't rely on a gps at all. i *use* a gps as a navigational aid.
    >
    > anyone who blindly follows a gps without using their brain deserves
    > what they get. expecting a gps to give perfect directions in all
    > situations is just asking for trouble.
    >
    > that's how stuff like this happens:
    > <http://abcnews.go.com/blogs/headlines/2012/03/gps-tracking-disaster-jap
    > anese-tourists-drive-straight-into-the-pacific/>
    >
    > <http://abcnews.go.com/Technology/gps-mishaps-trust-tech-leads-trouble/s
    > tory?id=10013723>
    >
    >>>> The one in my iPhone
    >>>> has Wakodahatchee in DelRay Beach, FL., about three blocks east of its
    >>>> location. My iPhone GPS insisted that I drive through a swamp to get to
    >>>> Zoo Miami. You don't have to believe me, look it up for yourself.
    >>>
    >>> that's a map error, not a gps error.
    >>>
    >>> in addition to apple's and google's maps, there are at least 7 gps apps
    >>> for the iphone that i can think of (navigon, tomtom, magellan, garmin,
    >>> copilot, motionx, waze), each of which has its own idea about what
    >>> roads are where and how to best route on them.

    >>
    >> Gee. I hadn't thought of that...

    >
    > now you do.
    >
    >> What a great idea. If my ability to
    >> find my desired location is impaired, just try another. Do I do so while
    >> driving, or stop on a busy road, hoping I will get one of the lucky seven.

    >
    > if you can't figure that out, then you deserve to get stuck in a swamp.


    You have zero sarcastic radar.


    >
    >>> if one of those apps tells you to drive through a swamp then either
    >>> report the map error or switch to a different app (or both).
    >>>
    >>> i also notice that you've switched from the garmin missed exit to the
    >>> iphone. what were you saying about bullshitting your way out?

    >>
    >> Gee you are observant. If only you had comprehensive ability. But that
    >> would be expecting too much.

    >
    > the only thing to expect are moronic insults from you.
    >
    >>>>>> Despite claims to the contrary, I am
    >>>>>> not convinced that selective Availability has been turned off.
    >>>>>
    >>>>> it definitely has. anyone who thinks otherwise is confused.
    >>>>
    >>>> I find your reassurance comforting.
    >>>
    >>> s/a was turned off may, 2000.
    >>>
    >>> this is a fact that anyone can confirm.
    >>>
    >>> it's without question, off.

    >>
    >> Yup!

    >
    > in other words, you admit you were lying.
    >

    Never said that. What you don't seem to understand is that national
    security needs have most likely found a workable substitute, so that
    commercial use is more effective. It may not be called SA, but for
    functional purposes, it will be effective.
    Are you really dumb enough to believe everything the government says,
    without questioning it. Well maybe you are.


    --
    PeterN
     
    PeterN, May 1, 2013
    #11
  12. nospam

    nospam Guest

    In article <51817454$0$10762$-secrets.com>, PeterN
    <> wrote:

    > >>>>>> Despite claims to the contrary, I am
    > >>>>>> not convinced that selective Availability has been turned off.
    > >>>>>
    > >>>>> it definitely has. anyone who thinks otherwise is confused.
    > >>>>
    > >>>> I find your reassurance comforting.
    > >>>
    > >>> s/a was turned off may, 2000.
    > >>>
    > >>> this is a fact that anyone can confirm.
    > >>>
    > >>> it's without question, off.
    > >>
    > >> Yup!

    > >
    > > in other words, you admit you were lying.
    > >

    > Never said that.


    yes it is. first you said you're not convinced it's off then you agree
    that it has been off for 13 years.

    > What you don't seem to understand is that national
    > security needs have most likely found a workable substitute, so that
    > commercial use is more effective. It may not be called SA, but for
    > functional purposes, it will be effective.


    keep trying to bullshit your way out.

    > Are you really dumb enough to believe everything the government says,
    > without questioning it. Well maybe you are.


    i don't believe what the government says, but that's irrelevant.

    s/a is off. end of story.
     
    nospam, May 1, 2013
    #12
  13. nospam

    PeterN Guest

    On 5/1/2013 4:42 PM, Alan Browne wrote:
    > On 2013.05.01 16:00 , PeterN wrote:
    >
    >> Never said that. What you don't seem to understand is that national
    >> security needs have most likely found a workable substitute, so that
    >> commercial use is more effective. It may not be called SA, but for
    >> functional purposes, it will be effective.

    >
    > There is no need for SA at all. That is why it's not even set up on the
    > most recent satellites.
    >
    > Prior to Clinton ordering the shutdown of SA there was a lot of testing
    > of military receivers ability to overcome jamming by virtue of L1/L2
    > tracking of the P/Y code portion of the GPS signal. In brief:
    >
    > 1. P/Y code has 10x the bandwidth and therefore is harder to jam than
    > C/A code.
    >
    > 2. There are two separate frequencies (L1 and L2) on military receivers,
    > so that much harder still (L1 and L2 is not just for improved accuracy).
    >
    > 3. Y-code is encrypted P code. Harder to spoof. Only military
    > receivers carry the W codes to decrypt it. The code changes every 7 days.
    >
    > So when the military wants to deny C/A (Coarse/Acquisition - the code
    > that civil GPS receivers use) they can simply jam it enough to make it
    > difficult for the enemy to use. Or spoof it (locally, not from the GPS
    > sats) to cause large navigation errors for the enemy.
    >
    > Meanwhile US, NATO and other "friendly" military users will be immune to
    > the jamming and spoofing as they'll be using all that "un jammed"
    > bandwidth.
    >
    > Some military systems will also have CRPA antennas that steer a null
    > towards the jamming source making it essentially "quiet" at the receiver.
    >


    Thanks for that clear and reasonable explanation. I was referring to SA
    in a generic sense, and had difficulty believing that there is no
    difference between the military technology and its civilian equivalent.

    --
    PeterN
     
    PeterN, May 2, 2013
    #13
  14. nospam

    PeterN Guest

    On 5/2/2013 1:25 PM, Alan Browne wrote:
    > On 2013.05.02 00:14 , PeterN wrote:
    >> On 5/1/2013 4:42 PM, Alan Browne wrote:
    >>> On 2013.05.01 16:00 , PeterN wrote:
    >>>
    >>>> Never said that. What you don't seem to understand is that national
    >>>> security needs have most likely found a workable substitute, so that
    >>>> commercial use is more effective. It may not be called SA, but for
    >>>> functional purposes, it will be effective.
    >>>
    >>> There is no need for SA at all. That is why it's not even set up on the
    >>> most recent satellites.
    >>>
    >>> Prior to Clinton ordering the shutdown of SA there was a lot of testing
    >>> of military receivers ability to overcome jamming by virtue of L1/L2
    >>> tracking of the P/Y code portion of the GPS signal. In brief:
    >>>
    >>> 1. P/Y code has 10x the bandwidth and therefore is harder to jam than
    >>> C/A code.
    >>>
    >>> 2. There are two separate frequencies (L1 and L2) on military receivers,
    >>> so that much harder still (L1 and L2 is not just for improved accuracy).
    >>>
    >>> 3. Y-code is encrypted P code. Harder to spoof. Only military
    >>> receivers carry the W codes to decrypt it. The code changes every 7
    >>> days.
    >>>
    >>> So when the military wants to deny C/A (Coarse/Acquisition - the code
    >>> that civil GPS receivers use) they can simply jam it enough to make it
    >>> difficult for the enemy to use. Or spoof it (locally, not from the GPS
    >>> sats) to cause large navigation errors for the enemy.
    >>>
    >>> Meanwhile US, NATO and other "friendly" military users will be immune to
    >>> the jamming and spoofing as they'll be using all that "un jammed"
    >>> bandwidth.
    >>>
    >>> Some military systems will also have CRPA antennas that steer a null
    >>> towards the jamming source making it essentially "quiet" at the
    >>> receiver.
    >>>

    >>
    >> Thanks for that clear and reasonable explanation. I was referring to SA
    >> in a generic sense, and had difficulty believing that there is no
    >> difference between the military technology and its civilian equivalent.

    >
    > In the end the non-SA solution is much better since with SA it was
    > difficult to deny the enemy accuracy in, say Africa or Venezuela,
    > without affecting public users in the US or other friendly places. With
    > the local low altitude jam method you can affect a very small region.
    >
    > I don't know for a fact, but I suspect certain C-130J's and EA-18's have
    > C/A code jam/spoof capability.
    >


    I would hope so.

    --
    PeterN
     
    PeterN, May 2, 2013
    #14
  15. nospam

    J. Clarke Guest

    In article <51804a04$0$10832$-secrets.com>,
    says...
    >
    > On 4/28/2013 11:19 AM, nospam wrote:
    > > In article <>, Alan Browne
    > > <> wrote:
    > >
    > >>>> It also outperforms (signal strength/processing grunt) my in-car GPS and
    > >>>> my lowrance marine GPS by a mile (each of which cost much more than the
    > >>>> phone).
    > >>>
    > >>> doubtful.
    > >>
    > >> It depends what he means by "outperform". If it means faster
    > >> acquisition, he's right - but he'll have no idea how bad the quality of
    > >> the solution is.

    > >
    > > he said signal strength/processing grunt, whatever that means.
    > >
    > > a smartphone might have a more capable processor (how many dedicated
    > > gps units have a multicore cpu and gpu?), but that just makes for
    > > pretty graphics and a responsive interface.
    > >
    > > it says nothing about the radio, which is what matters.
    > >
    > >> A marine GPS (like aviation) should be conservative. That results in
    > >> slower acquisition, but better certainty about the quality of the
    > >> solution. Since marine units operate in areas without much obstruction
    > >> to the sky (typically) a conservative acquisition/tracking threshold is
    > >> a good idea. Some marine units also allow you to enter the altitude of
    > >> the surface you are on (lake elevation for example) and that gives you a
    > >> "free" virtual satellite located at the center of the earth.
    > >>
    > >> (Indeed, if the altitude setting is used, but incorrect by a good bit,
    > >> it will drag the position solution with it a good way unless RAIM is
    > >> used to discard it. I don't believe any marine units use RAIM however).
    > >>
    > >> I don't have much of an opinion on automobile GPS sets. They seem to do
    > >> well, but will occasionally show a wild error (show position on a
    > >> parallel street 2 blocks away; or on the service road, etc.).
    > >>
    > >> Mine seems to use the map for position aiding. When I drive off road at
    > >> an angle, the position will show as on the road until I'm about 100m off
    > >> of the road.

    > >
    > > i've never seen a 2 block error in a car, but have seen it lock to the
    > > frontage road right next to the highway or vice versa. it's rarely an
    > > issue since it's obvious what it should be and it quickly corrects
    > > itself anyway.
    > >

    >
    > You would have if you were using my Garmin today. It told me to make a
    > turn just after I passed the exit. Despite claims to the contrary, I am
    > not convinced that selective Availability has been turned off.


    That's more likely to be a map error. Try the same route another time
    and see if it does it again. The maps aren't perfect. One of my
    favorites is the time it told me to turn left onto an on-ramp, which
    would require that I cross a median, a guard rail, and four lanes of
    oncoming traffic, then climb an embankment. When I finally got to the
    real on-ramp I could see where there used to be another one where it was
    telling me to turn. Another is the time that I was following its
    directions and the road was first nicely paved, then got somewhat
    dilapidated, then turned to gravel, then dirt, then a cowpath, and the
    cowpath finally came to a hole cut in a chain-link fence. At that point
    I decided to backtrack and look for an alternate route.
     
    J. Clarke, May 9, 2013
    #15
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