4 ms·

I talked to a guy a few weeks ago who worked for a company that developed a guidance system before GPS that used stars like a sextant to navigate. Pretty crazy

I talked to a guy a few weeks ago who worked for a company that developed a guidance system before GPS that used stars like a sextant to navigate. Pretty crazy to think about.

jihadjihad 5y ago
Something in that vein that has always amazed me, even though its performance in the field left something to be desired, is the Norden bombsight [0]. "The Norden [used] an analog computer that continuously recalculated the bomb's impact point based on changing flight conditions, and an autopilot that reacted quickly and accurately to changes in the wind or other effects." 0: https://en.wikipedia.org/wiki/Norden_bombsight https://en.wikipedia.org/wiki/Norden_bombsight
rwmurrayVT 5y ago
It is also common in shiprepair to use the stars for aligning equipment with a theodolite like device.
IMSAI8080 5y ago
Spacecraft often use stars to orient themselves. The Voyager spacecraft have star trackers to keep the antenna pointing at Earth. They look for the Canopus star.
- stjohnswarts 5y ago
  Don't they need more than 1 star to get an orientation? I mean other than brightness 1 star doesn't give you a lot of information?
  - fho 5y ago
    I guess if they can confirm that it is a specific star they know where on a I finite line they are. If that line happens to be through earth and the space craft they know where to point their antenna.
  - IMSAI8080 5y ago
    Yes, I think the tracker also uses the sun as I remember reading.
_moof 5y ago
GPS and celnav (and other forms of navigation, radio or otherwise) are really not so different when you get down to fundamentals. At their core they are all about locating the intersection of multiple lines, circles, or spheres of position, depending on how many dimensions you're working with. The major differences are in how you come up with the LOPs. The odd man out, if you will, is inertial nav, which has more in common with dead reckoning.
sciurus 5y ago
This is still important, e.g. the Navy teaches celestial navigation in case GPS is disrupted. https://www.thedrive.com/the-war-zone/3865/this-is-likely-why-the-navy-is-causing-a-massive-and-mysterious-gps-outage-in-the-western-us https://www.thedrive.com/the-war-zone/3865/this-is-likely-wh...
ethbr0 5y ago
Star trackers https://en.m.wikipedia.org/wiki/Star_tracker https://en.m.wikipedia.org/wiki/Star_tracker Ironically, the last one I touched was a piece of donated Russian equipment, intended for spacecraft use, with no manual.

I talked to a guy a few weeks ago who worked for a company that developed a guidance system before GPS that used stars like a sextant to navigate. Pretty crazy to think about.

jihadjihad 5y ago

Something in that vein that has always amazed me, even though its performance in the field left something to be desired, is the Norden bombsight [0]. "The Norden [used] an analog computer that continuously recalculated the bomb's impact point based on changing flight conditions, and an autopilot that reacted quickly and accurately to changes in the wind or other effects." 0: https://en.wikipedia.org/wiki/Norden_bombsight https://en.wikipedia.org/wiki/Norden_bombsight

rwmurrayVT 5y ago

It is also common in shiprepair to use the stars for aligning equipment with a theodolite like device.

IMSAI8080 5y ago

Spacecraft often use stars to orient themselves. The Voyager spacecraft have star trackers to keep the antenna pointing at Earth. They look for the Canopus star.

stjohnswarts 5y ago
Don't they need more than 1 star to get an orientation? I mean other than brightness 1 star doesn't give you a lot of information?
- fho 5y ago
  I guess if they can confirm that it is a specific star they know where on a I finite line they are. If that line happens to be through earth and the space craft they know where to point their antenna.
- IMSAI8080 5y ago
  Yes, I think the tracker also uses the sun as I remember reading.

_moof 5y ago

GPS and celnav (and other forms of navigation, radio or otherwise) are really not so different when you get down to fundamentals. At their core they are all about locating the intersection of multiple lines, circles, or spheres of position, depending on how many dimensions you're working with. The major differences are in how you come up with the LOPs. The odd man out, if you will, is inertial nav, which has more in common with dead reckoning.

sciurus 5y ago

This is still important, e.g. the Navy teaches celestial navigation in case GPS is disrupted. https://www.thedrive.com/the-war-zone/3865/this-is-likely-why-the-navy-is-causing-a-massive-and-mysterious-gps-outage-in-the-western-us https://www.thedrive.com/the-war-zone/3865/this-is-likely-wh...

ethbr0 5y ago

Star trackers https://en.m.wikipedia.org/wiki/Star_tracker https://en.m.wikipedia.org/wiki/Star_tracker Ironically, the last one I touched was a piece of donated Russian equipment, intended for spacecraft use, with no manual.