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    Re: GPS Anti Spoof app
    From: Frank Reed
    Date: 2018 Jan 1, 13:01 -0800

    Andrés you wrote:
    "it seems that your app is well inspired by mine"

    Ha ha. :) I wouldn't know... --simply because I have never looked at your apps! Not because there's anything that I think might be wrong with them. I'm sure your apps are works of art and inspirations to many people. Rather, I don't look at other people's apps because I like to create from scratch, un-influenced by pre-existing products. It's more fun that way, and I think much more likely to produce quality and innovation.

    But I think I need to ask you to clarify this. When you described my app as "well inspired by" yours, you weren't actually suggesting that I somehow "copied" or "duplicated" or "mimicked" your app, were you? That's almost what you seem to be implying. Of course, your English is truly excellent, but sometimes there can be small differences in meaning that arise. Maybe with "well inspired by" you just meant "similar to"? You can clarify what you meant, I am sure.


    Just a reminder, since you brought it up, here's a quick list of some of the benefits of my GPS Anti Spoof app:

    • The sextant altitude is generated from the GPS position. Therefore if the GPS is being spoofed at any scale larger than a few miles, it is instantly detectable (in one axis) with a quick sextant sight and no paperwork, no calculation.
    • When no GPS spoofing is occurring or suspected, the same app serves as a sight trainer, a sextant practice aid providing instant, highly-accurate feedback. You get better at taking sights when you use this app.
    • Generated sextant altitudes are as accurate as possible at the level of a tenth of a minute of arc if the standard details have been entered on the Settings screen, and if weather corrections are available for very low altitude sights.
    • Device (phone/tablet) system time is automatically corrected so that the UT used in calculations is accurate to a small fraction of a second in general use.
    • Altitudes are automatically corrected for deflection of the vertical. This correction can amount to over a minute of an arc (or more than a nautical mile in the position) in some parts of the world's oceans. At the present time, no other apps that I am aware of handle this issue, and on that one-percent segment of many of the world's major ocean routes where the DOV is significant, all other apps produce inferior celestial navigation information.
    • The app also includes the Sun's or star's azimuth, and for users who prefer a line of position plot on a chart, the difference between the raw observed altitude and the altitude instantly displayed by the app is identical to the "intercept" distance, and the azimuth is provided simultaneously. No sight reduction required.

    Frank Reed
    Clockwork Mapping / ReedNavigation.com
    Conanicut Island USA

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