GPS Anti Spoof 1.0.37

This application offers a sophisticated approach to celestial navigation by providing an instant comparison between observed altitudes and high-precision, live-calculated altitudes. Users can simply capture the Sun's position, pause the app, and receive immediate feedback on their observations.

The standard version of the app covers essential celestial bodies such as the Sun, Venus, and two stars, suitable for novice navigators. In contrast, the Pro version is tailored for professionals and includes comprehensive data for the Sun, Moon, Venus, Mars, Jupiter, Saturn, the 57 standard navigational stars, and Polaris. Importantly, both versions operate off-network, making them viable choices for maritime navigation; however, the standard version is limited to three days of off-network functionality, whereas the Pro version supports extended use for several weeks in remote oceanic locations.

Designed to calculate precise altitudes relevant for both land and sea navigation (contingent upon an accurate GPS position), this app eliminates the need for cumbersome paperwork or correction tables. It seamlessly integrates all necessary corrections—including index error, system time error, dip of the horizon, refraction adjustments based on temperature and pressure, altitude above sea level, parallax, and even gravitational deflection of the vertical—automatically. Notably, if there is a GPS spoofing incident at sea causing discrepancies in observed positions, this app provides mariners with a reliable mechanism to detect such inaccuracies through occasional sextant sightings.

In scenarios where GPS spoofing is not a concern, the app also serves as an effective celestial navigation trainer. Users can take a sighting and instantly compare it with the app's display. This real-time feedback significantly enhances celestial sextant skills in a matter of hours rather than days or weeks.

The application remains fully functional off-network in remote areas. For those with access to a network connection, it automatically downloads pertinent temperature and pressure information; alternatively, users have the option to input weather data manually if preferred.

Importantly, the ephemeris data is derived from JPL's numerical integrations of lunar and planetary motions established in the official Nautical Almanac and Astronomical Almanac. The coordinates are precise to one second of arc, while the displayed altitudes are accurate to one-tenth of a minute of arc.