Can it be used on the moon?
Maybe, but only on the near side. It really needs its own constellation (and the satellites wouldn’t be in stable orbits).
6 thoughts on “GPS”
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Can it be used on the moon?
Maybe, but only on the near side. It really needs its own constellation (and the satellites wouldn’t be in stable orbits).
Comments are closed.
It really needs its own constellation
I saw Glenn posted about this at Insty. He thought it was a good idea, but I agree the moon needs its own constellation. And not only for GPS, but another like Starlink to allow for communication across the surface. I’ve always felt those items being put in place would signal a serious effort to begin colonization. They are not absolutely necessary, but they will give the new colonies key infrastructure that won’t require in-situ resources.
The only reason we need GPS is that we can’t see the stars most of the time. We can see them in space all of the time, and together with an accurate time-piece (which we have on steroids) that provides anyone with the ability to navigate precisely.
I would advise caution when considering putting up lots of RF sources beyond the Moon. Right now it’s the only place in the Solar System that is shielded from the RF cacophony eliminating from Earth. I think that radio astronomy is more of a priority than broadband internet to the lunar farside.
That should have been “emanating”. Damn spell check…
Earth based GPS from the moon would have very poor GDOP.
“Cheung and Lee plotted the orbits of navigation satellites from the United States’s Global Positioning System and two of its counterparts, Europe’s Galileo and Russia’s GLONASS system—81 satellites in all. Most of them have directional antennas transmitting toward Earth’s surface, but their signals also radiate into space.”
Wiki:
“GLONASS is a global navigation satellite system, providing real time position and velocity determination for military and civilian users. The satellites are located in middle circular orbit at 19,100 kilometres (11,900 mi) altitude with a 64.8 degree inclination and a period of 11 hours and 15 minutes. GLONASS’s orbit makes it especially suited for usage in high latitudes (north or south), where getting a GPS signal can be problematic.”
But it seems you want a Molniya orbit: wiki
“The exact height of a satellite in a Molniya orbit varies between missions, but a typical orbit will have a perigee of approximately 600 kilometres (370 mi) and an apogee of 39,700 kilometres (24,700 mi), for a semi-major axis of 26,600 kilometres (16,500 mi).”
That should work for Lunar north pole, but you need satellites in Molniya orbit for the lunar south polar region. And/or put them in even higher orbit for purpose of more triangulation for polar regions. But there should locations on the farside of either north or south lunar polar regions that you could see Earth, though not seeing Earth all the time.
But for communication it seems you want relays on lunar surface if operating in lunar polar regions. And one relay should be able to tell you where you are. It should able to take a picture of you.
If a radio astronomy observatory is set up on lunar farside, it needs to be connected to nearside by a fiber optic cable ONLY.
My former colleague made the suggestion yesterday that, as we have good lunar maps, ground vehicles can be navigated by terrain matching by looking at the horizon. Could probably do this by adapting some of the self driving technology that is in development.
Instread of GPS like systems maybe there will be a requirement for a very small automated star tracking astronav device to be mounted on vehicles, ground and space.