Ships must practice celestial navigation

Original Article ↗ Hacker News Discussion ↗

Maritime and military enthusiasts debate the renewed push for celestial navigation training in the U.S. Navy as a hedge against GPS jamming, hacking, or loss of electronic systems. Commenters weigh how far low-cost tools like smartphones, quartz clocks, and plastic sextants can realistically substitute for high-end gear, and note that solo sailors and past aviators have long navigated accurately by stars. The conversation broadens into calls for robust civilian GNSS backups such as eLoran, and into geopolitical concerns about overreliance on U.S.-controlled space and navigation infrastructure.

Smartphones, Sensors, and Automated Celestial Navigation

  • Some argue modern phones have adequate sensors (clock, camera, accelerometer) to support sextant-style navigation or even full star-tracking with software.
  • Counterpoint: sensor accuracy and calibration (especially tilt) are limiting, though people already use apps as “fancy calculators” to verify hand calculations.
  • Discussion of pixel-level star tracking suggests arcsecond-level attitude is possible; accelerometer noise can be averaged down, but requires time and careful alignment.
  • EMP or hacking risk is raised as a reason not to rely on smartphones; others question how much of a ship’s electronics would survive anyway.

Celestial Navigation Methods and Equipment

  • Several commenters say the article understates what’s possible at night; lunar distance methods and planetary observations can yield fixes with basic sextant and watch.
  • Being without a precise fix for ~12 hours is considered acceptable if dead reckoning is used.
  • Bubble sextants are noted as more an aviation tool; marine sextants are available used for a few hundred dollars, so “expensive” is contested.
  • Some highlight that the Navy team’s 2 nm track accuracy is actually quite good, especially with many novices.

Backups to GNSS: eLoran, Quantum Nav, and Civil Use

  • Strong support for non-GPS backups like eLoran; China’s deployment is cited as an example.
  • Quantum navigation is mentioned primarily for submarines; critics note this doesn’t help merchant shipping or civilian timing needs.
  • It’s emphasized that any robust strategy must consider civilian infrastructure, not just military users.

Military and Civil Training in Non-Electronic Navigation

  • Ground combat units reportedly still practice map-and-compass land navigation; celestial nav on land is seen as rarely necessary.
  • Sea navigation is considered more demanding because of lack of landmarks and greater isolation.
  • There is praise for maintaining proficiency with sextants, tables, and even slide rules, since skills decay without practice.

Timekeeping, EMP, and Chronometers

  • Debate over whether ships need mechanical chronometers versus quartz devices.
  • Consensus that non-networked quartz clocks are far more accurate than mechanical ones and can be EMP-hardened with simple Faraday shielding.

Analog vs Digital, Units, and Pedantry

  • One subthread distinguishes “digital” (discrete numbers, tables) from “electronic,” noting that much “analog” navigation actually uses digital steps (tables, written numbers).
  • Brief debate over whether nautical miles and knots count as “US customary” units and criticism of mixed-unit systems (yards vs nautical miles).

Automated Star Trackers and Historical Systems

  • Star trackers on spacecraft and aircraft (e.g., SR‑71, ICBMs) are cited as prior art for automatic celestial navigation.
  • Papers and systems like STELLA show star-tracking is mature; the hard part is accurate “down” reference without a visible horizon, requiring good inertial sensors.

Geopolitical Tangents: NATO, Europe, BRICS

  • Large subthread veers into NATO burden-sharing, European defense autonomy, and US reliability as an ally.
  • Some argue Europe overrelies on US military power; others counter that US also benefits strategically from bases and alliances.
  • BRICS is debated: some see it as a serious challenge to Western hegemony, others as incoherent and internally conflicted.
  • Concerns about Russian and Chinese ambitions, nuclear proliferation, and information warfare appear, but views diverge sharply on both threat level and Western responses.

Jamming, Races, and “Analog” Culture

  • Real-world GPS jamming in areas like the Baltic is mentioned as evidence that GNSS is fragile.
  • A retro round-the-world yacht race banning modern electronics is cited as an example that long voyages via celestial and paper navigation remain viable, though demanding.