NASA Successfully Acquires GPS Signals on Moon

More details at <a href="https:&#x2F;&#x2F;www.gpsworld.com&#x2F;lugre-receiver-captures-gnss-signals-in-lunar-orbit&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.gpsworld.com&#x2F;lugre-receiver-captures-gnss-signal...</a><p>&quot;Despite the challenges of distance and velocity, the receiver achieved position accuracy within 1.5 km and velocity accuracy within 2 m&#x2F;s. It successfully acquired signals from four GPS satellites (L1 and L5 frequencies) and one Galileo satellite (E1-E5 bands) during a one-hour observation window. Post-landing,&quot;

Oooooh. I guess that although the signal will be fainter, as they&#x27;re ~21x further away than usual (240k miles vs 20k), they&#x27;ll have the advantage of having less noise and practically no signal bouncing.<p>What I don&#x27;t know is: Even when receiving a good signal... how difficult would be calculating location when satellites are going to be all concentrated in a really small portion of the sky, and all of them in a proportionally small distance between them, compared to the distance of the receptor?

While the headline says GPS, the article says signals were acquired from GPS and Galileo, which increases the number of GNSS satellites available to get a location fix.

It is not clear from the article, and these are noob questions: does it mean there were no other time dilation effects to take into account? In other words, is the adjustment done within the satellite clocks enough for the signal processing near or on the moon to get the position since the moon is so far off)?

They tried on the moon, but there does not seem to be an assumption that this is limited to the moon? So one could obtain a position anywhere in earth&#x27;s orbit, up to heights of 380.000km? 1.5km accuracy is impressive then.<p>Apart from the attenuation from distance, I would expect that the navigation sallellites point their antennas mostly downwards to earth, but you might find some that radiate outwards. I don&#x27;t think you can expect to receive from half the satellites though.

I like this because it&#x27;s such a neat unexpected idea to try.

Super cool! This only works on the side facing the GNSS constellation, right? There is no signal to use on the other side.

So when do we put up GPS satellites around Mars? It makes sense. Or just put them on the moons I guess. They&#x27;re pretty far from the surface - 9K and 14K compared to GPS of 12K so maybe not bad. And less atmosphere in the way. Also less radio noise?

Does this make the ESA’s Pathfinder [1] redundant? Or are they measuring something materially different?<p>[1] <a href="https:&#x2F;&#x2F;www.esa.int&#x2F;ESA_Multimedia&#x2F;Images&#x2F;2023&#x2F;06&#x2F;Satnav_from_Earth_to_the_Moon" rel="nofollow">https:&#x2F;&#x2F;www.esa.int&#x2F;ESA_Multimedia&#x2F;Images&#x2F;2023&#x2F;06&#x2F;Satnav_fro...</a>

This is awesome. It means we will know where we aren&#x27;t when we&#x27;re on the moon.

My prior understanding was that the Artemis project included creating PNT (position, navigation, timing) in cislunar space, and that Earth&#x27;s GNSS satellites wouldn&#x27;t be sufficient. Is that plan now changed?

I&#x27;m curious what coordinate system they&#x27;re using and how the math worked a little more.<p>I guess technically they could use latitude and longitude projected all the way out to the moon, but that would be pretty hard to use.

I&#x27;m surprised that any useful accuracy can be obtained. Maybe an additional input to the solution would be to watch when various GPS satellites are occulted by the Earth.

Would this be used for location services or rather timestamping?<p>Would it be possible to use celestial navigation to obtain a more precise location?

So GPS a misnomer now, given not only &quot;global&quot; anymore. Perhaps better change it to CPS, Cislunar Positioning System.

Use 1 km towers spaced every 100 km on the Moon&#x27;s surface instead. No satellites needed.

Smart munitions on moon when?

...then is immediately ordered to sell them to a private equity firm, payable in $TRUMP.

Don’t forget your phone on the Artemis mission so you can catch some sweet rare Pokémon!

Breaking: NASA discovers using Lunar GPS that taking a slingshot detour around the moon is still faster than commuting directly through I-10 during rush hour.

I used to get excited for these kinds of news, and from a science perspective, this is very cool.<p>On the other hand, as we get closer to colonize other planets, or at least try to plan for this end, I get depressed more and more.<p>We&#x27;re enough burden for a single planet, and definitely too much for a solar system.<p>Honestly, no, I don&#x27;t want more humans around.