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    Re: Smartphone navigation
    From: Ken Gebhart
    Date: 2012 Jul 20, 22:10 -0500

    Thanks for a wonderful essay on smartphones. Some of us old guys have
    a hard time keeping up with the latest inovations.
    Ken Gebhart
    On Jul 20, 2012, at 3:39 PM, Frank Reed wrote:
    > Modern "smartphones" are pocket computers. They can do amazing
    > things even without being activated as a phone. For example, I have
    > an "old" first-generation iPhone from late 2007. It has no phone
    > service, but it is fully WiFi capable so I have it as a spare
    > Internet access device. If I am upstairs and my phone (a two-year-
    > old Android Smarthpone) and laptop are downstairs, and my upstairs
    > computer is off, no problem. I pick up the old iPhone, and I can
    > almost instantly view any web site, check email, check NavList
    > messages, and so on. I can also launch spreadsheets and run various
    > astronomy programs that can do nearly anything that I would expect
    > to see in a "desktop" computer astronomy application. Solve a
    > spherical triangle correctly in all angular ranges? Hell, they do
    > that in hardware --it's on the GPS chipset!
    > Modern smartphones are more than pocket computers because they also
    > include a "rich" suite of sensors. And that's an understatement.
    > Smartphones can listen. If you've never seen "Shazam" in operation,
    > it will seem like magic. A song is playing on the radio... you
    > decide you want to follow the lyrics... so you tap an icon on your
    > smartphone, tap another icon to set it "listening" and in five or
    > ten second it comes back with the name of the song, the artist, the
    > album artwork, a link to the lyrics, and more. And for many songs,
    > if you tap another button, it will go into a "karaoke" mode and
    > display the lyrics synched to the song still playing on the radio.
    > This isn't science fiction. I do it almost every day.
    > Smartphones can see. And I don't mean that they're cameras. They
    > are indeed cameras, and smartphones have nearly wiped out the
    > pocket camera market. But it goes beyond that. They can analyze
    > what they "see". This functionality is relatively limited, but if
    > you start up an app, for example, "Google Goggles" on your phone
    > and point the phone at a piece of artwork (maybe a Renaissance
    > painting in an advertisement in a magazine), or the cover of an old
    > paperback book, or a logo on a bottle of wine, the app will analyze
    > the image and then compare it with Google's vast database of images
    > and often locate an exact match. In the case of the painting in the
    > advertisement, it will then most likely link you to the Wikipedia
    > article for the artist who painted it. And of course, this
    > functionality can include translation: photograph a street sign in,
    > say, Portuguese, and your phone will translate it for you. This
    > basic "vision" functionality has been available for several years
    > now. Big improvements are in the pipeline.
    > Smartphones can measure altitudes and find directions. The earliest
    > smartphones included accelerometers in two dimensions that could
    > determine the tilt of the phone in two directions. This has obvious
    > applications for leveling applications and basic celestial
    > navigation. But bear in mind that the accuracy is no better than a
    > tenth of a degree AND the device has to be calibrated since the
    > accelerometers are aligned with the frame of the smartphone only to
    > within a degree or two (in other words, there is an index
    > correction, unless it is calibrated manually, of more than a degree
    > in most cases). Nonetheless, this has made angular altitude
    > measurement with Smartphones a relatively trivial application for
    > nearly five years now. Back in the Spring of 2009 rumors began
    > circulating that new smartphones would also have electronic
    > compasses, and at that point, as I am sure some of you recall, I
    > posted on NavList about how this could turn any smartphone into a
    > star finder (and there was much "grumbling" on NavList about the
    > impossibility of this). Less than a month later, Google Sky Map
    > (now known simply as Sky Map since they have made it open source)
    > became available and now there are numerous "point and shoot" apps
    > for star-finding on smartphones (e.g. "Pocket Universe" on
    > iPhones). It's important to recognize that these are only as good
    > as the calibration of the compass. Since many smartphone users do
    > not know that they have to wave the device around in a peculiar
    > fashion to calibrate the magnetic compass (and since those who
    > know, often feel embarrassed doing it), the direction capability is
    > sometimes wrong by 10 or 20 or even 45 degrees. When calibrated,
    > the error is typically less than five degrees. For over a year now,
    > many smartphones have also been equipped with an electronic
    > gyroscope. This can separate changes in orientation from linear
    > accelerations, which is very useful in games but also in star-
    > finding apps since it tends to smooth out the turns. I cannot
    > emphasize enough that star-finding apps like this are tremendous
    > crowd-pleasers. They are a fantastic way to learn the stars, both
    > for beginners and experts. For myself, I enjoy placing the device
    > on a table with Sky Map running. It lets me "look through the
    > Earth" and see what stars are in the nadir at that time, something
    > that we are rarely aware of even when we know the night sky well.
    > Smartphones can determine your position. Long before iPhones and
    > Android phones, smartphones have had GPS chipsets and other more
    > coarse means of determining the user's position. There are now
    > multiple methods of position-determination. GPS positions provide a
    > fix within just a few seconds. There's no long bootup wait like in
    > old GPS receivers since the network now provides the startup data
    > to the device based on its coarse position which is found from
    > Internet "IP" address or from the location of the nearest cell
    > tower. In addition, huge databases have been created, originally by
    > small startups but they have all been eclipsed by the Google beast,
    > which provide the physical locations of millions of home WiFi
    > networks. Those trucks that compile photography for Google
    > Streetview are also sniffing the id's and signal strengths from the
    > WiFi in you home and business. This WiFi-based positioning is
    > nearly as accurate as GPS and it works especially well in those
    > "urban canyons" where GPS is not quite so reliable. And note that
    > even a coarse position based on network location is more than
    > enough for star-finding and most astronomy applications.
    > Smartphones create augmented reality. By combining multiple sensors
    > and especially the device's camera, it is possible to display data
    > directly on the camera's live view of a scene. You aim your phone
    > down a street and it labels every restaurant, for example, and
    > shows yelp ratings in little bubbles floating over each one. This
    > sort of application has been slow to catch on in large part because
    > of the embarrassment factor of aiming your phone down a street.
    > Smartphones are watching you. Among the most recent enhancements
    > are phones that watch your eyes and know whether you're reading the
    > screen. If you're still reading, the display will not "time out"
    > and go dark. Strange but true. Disturbing yet practical. And
    > smartphones are already doing facial recognition but strictly on an
    > "opt in" basis because of privacy concerns. In other words, the
    > technology can identify specific individuals and note their
    > presence in photo after photo but you have to tell the phone that
    > this person is "Jane Doe" from your contacts list.
    > A short note on naming: there are at this time two dominant
    > operating systems on smartphones and related tablet computers. They
    > are iOS and Android. Apple created and developed the iPhone, first
    > launched in 2007 and they have since named its operating system
    > "iOS" to cover the multiple devices it runs on, especially the
    > sizzling hot iPad. Google almost simultaneously launched the
    > Android operating system to steal as much as they could from
    > Apple's projects without going to jail. There is a good analogy
    > here with the Mac versus Windows in the 80s and 90s. Since Apple
    > has not licensed iOS and probably never will, the market of devices
    > which run iOS is quite small but beautifully integrated and
    > efficient. It's "iPhones" and "iPads" with the "iPod Touch" as a
    > minor shrub in the Apple orchard. From the outset, Google has
    > attempted to make friends and influence corporate partners by
    > selling Android as the "open" alternative to Apple's walled
    > orchard. This has also partially protected Google from massive
    > lawsuits since Apple has gone after the device manufacturers who
    > use the Android operating system first. This approach has led to a
    > proliferation of devices and serious fragmentation of the market
    > (since there are numerous major versions and minor variants of
    > Android). In addition, all of these devices have unique names
    > despite the fact that they are all running Android. So for example
    > there are Heros, and Nexuses, and Galaxies, and even the Nook and
    > the latest Kindle tablets run Android. There is also a line of
    > phones from Motorola called Droids. This is where things can get
    > confusing. All Droids run Android, but by no means all Android
    > devices are Droids. For people who are familiar with the Apple side
    > of the market, this is especially surprising. Incidentally, the
    > name "Android" required no special licensing since it is a long-
    > standing generic science fiction term. But Motorola had to license
    > the name "Droid" from a very wealthy man. Can you guess who? Hint:
    > "These aren't the droids we're looking for."
    > Finally, as far as Gary's report of less than 5 minutes of arc
    > error in an LOP from a smartphone app, that's either good luck or
    > it's an app that is cheating (perhaps even in a way that the
    > programmer did not realize). There's no magic here --beyond the
    > amazing magic that you get all of these features in a handheld
    > device... oh, and it's a phone, too... :). The device cannot be
    > better than an ordinary bubble sextant as far as altitude
    > measurements go. Without calibration for index error, you can
    > expect errors in LOPs of one or two degrees. With calibration and
    > assuming no magnification and sighting along the edge of the
    > device, you could expect no better than about half a degree
    > accuracy on a single sight. This could be improved exactly the way
    > that traditional bubble sextants improved accuracy by averaging
    > over time. And of course, this would be an easy addition to a
    > smartphone app. If there's calibration for index correction, and if
    > averaging is done, and if there's a nice clean edge to sight along
    > (no guarantee given the multitude of Android devices), I think you
    > could expect standard deviation errors in sights on the order of
    > five to ten minutes of arc. Of course, if we throw in coarse
    > positioning from a user-input DR or from the network, the device
    > could also usually guess what stars you're looking at and you
    > wouldn't even need to know basic star patterns to get a position.
    > Useful? Probably not in any real practical sense. Fun? Well, for a
    > certain personality type. Myself included. :) Educational?
    > Absolutely, if you ask students to figure out what the device is
    > doing and relate it back to historical navigation, there's a
    > thousand lessons here. And that's really the great thing about all
    > of this: any "kid" with a smartphone, ignoring obvious financial
    > barriers for the moment, can download these software apps and learn
    > star-finding and navigation topics and a thousand other things...
    > There's tremendous opportunity for education.
    > -FER
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