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Mars helicopter employs advanced control techniques to survive in-flight anomaly

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Re: Mars helicopter employs advanced control techniques to survive in-flight anomaly

#11

Post by TheAdamAndChe »

anvandare wrote: post #6
anticristi wrote: post #3

Time to set up a GPS constellation on Mars? Somehow forgot that this navigation aid -- that we take for granted on Earth -- is missing on this other planet.

Pretty sure SpaceX's first deliveries to Mars (orbit) will include just that. I think they could probably use Starlink satellites without much modification (most important one I can think of would be more panels to cope with the reduced solar irradiance)? The GPS constellation has 32 satellites. A GPS satellite weighs ~2000kg. Starship should get 100-150 tons to Mars - the math checks out! (Disclosure: I got all my r…

It's funny/amazing to me how we lived without GPS for thousands of years, but it's become so integral to our society that it's one of the first things we're setting up there before visiting.

Re: Mars helicopter employs advanced control techniques to survive in-flight anomaly

#12

Post by LeifCarrotson »

anticristi wrote: post #3

Time to set up a GPS constellation on Mars? Somehow forgot that this navigation aid -- that we take for granted on Earth -- is missing on this other planet.

I think it would be an APS constellation, because Martian orbits like Areosynchronous get their prefix from the greek Ares.

That would be really cool, I wonder if it would be faster and more precise because there would be negligible human-produced radio noise to interfere and the Martian ionosphere is much thinner, or if it would be worse because the thinner and weaker atmosphere and magnetic field don't protect the receivers from solar noise.

I wonder if a rover could drop a few beacons for time-of-flight 2D triangulation, it's not like they're moving hundreds of miles away over the horizon.

Re: Mars helicopter employs advanced control techniques to survive in-flight anomaly

#13

Post by JoeAltmaier »

anticristi wrote: post #3

Time to set up a GPS constellation on Mars? Somehow forgot that this navigation aid -- that we take for granted on Earth -- is missing on this other planet.

GPS doesn't have to be satellites. It can simply be beacons on the ground. Often used terrestrially to get a few more decimal points on a fix.

Re: Mars helicopter employs advanced control techniques to survive in-flight anomaly

#15

Post by njoubert »

idiotsecant wrote: post #8
njoubert wrote: post #5

I see no mention of "advanced control techniques"? Sounds like there is just a limit on roll/pitch angles and a limit on distance applied. Saying "advanced control techniques [for multirotors]" sets an expectation for something along the lines of Tedrake's Underactuated Control approaches: http://underactuated.mit.edu/

Sensor fusion is part of the control system. Sensor fusion that incorporates visual information is outside of the typical classical controls sphere and is likely considered part of an advanced controls segment of the devices firmware as opposed to the bog standard deterministic controls algorithm. You need not gatekeep here, this is a real term.

The article title is still misleading. The sensor fusion was the root cause of the malfunction, it was not the advanced control technique that was deployed to survive the anomaly.

Re: Mars helicopter employs advanced control techniques to survive in-flight anomaly

#16

Post by kklisura »

Here's a research paper that might provide more information: "Vision-Based Navigation for the NASA Mars Helicopter" https://sci-hub.se/10.2514/6.2019-1411

> This paper provides an overview of the Mars Helicopter navigation system, architecture, sensors, vision processing and state estimation algorithms.

Re: Mars helicopter employs advanced control techniques to survive in-flight anomaly

#17

Post by anvandare »

TheAdamAndChe wrote: post #11
anvandare wrote: post #6

Earlier quoted context omitted.

Pretty sure SpaceX's first deliveries to Mars (orbit) will include just that. I think they could probably use Starlink satellites without much modification (most important one I can think of would be more panels to cope with the reduced solar irradiance)? The GPS constellation has 32 satellites. A GPS satellite weighs ~2000kg. Starship should get 100-150 tons to Mars - the math checks out! (Disclosure: I got all my r…

It's funny/amazing to me how we lived without GPS for thousands of years, but it's become so integral to our society that it's one of the first things we're setting up there before visiting.

> The first and most moral responsibility of Freeland will be establishing a decent brewery on the new planet. (Civilization: Beyond Earth - Hutama)

Sure, our ancestors (who could make their way and thrive in the wild) would probably consider me (who gets lost the moment I make a wrong right turn and depends on the local supermarket) a complete idiot, especially since I couldn't recreate any of the technology my daily life so depends on... But I've got central heating and clean tap-water, so I'm happy with the exchange.

The higher we climb the ladder of technological dependency, the more calamitous it becomes should we ever fall off. Best not to look down. (I think I'm supposed to bang rocks together to make fire, right?)

Re: Mars helicopter employs advanced control techniques to survive in-flight anomaly

#18

Post by jessriedel »

idiotsecant wrote: post #8
njoubert wrote: post #5

I see no mention of "advanced control techniques"? Sounds like there is just a limit on roll/pitch angles and a limit on distance applied. Saying "advanced control techniques [for multirotors]" sets an expectation for something along the lines of Tedrake's Underactuated Control approaches: http://underactuated.mit.edu/

Sensor fusion is part of the control system. Sensor fusion that incorporates visual information is outside of the typical classical controls sphere and is likely considered part of an advanced controls segment of the devices firmware as opposed to the bog standard deterministic controls algorithm. You need not gatekeep here, this is a real term.

I don't think this is gate keeping. Regardless of the terminology used within the field, the intended audience of this pop article will interpret "advanced" to mean actually unusual or at the cutting edge. Relying on the public's misinterpretation of jargon ought to be criticized.

Re: Mars helicopter employs advanced control techniques to survive in-flight anomaly

#19

Post by pilsetnieks »

LeifCarrotson wrote: post #12
anticristi wrote: post #3

Time to set up a GPS constellation on Mars? Somehow forgot that this navigation aid -- that we take for granted on Earth -- is missing on this other planet.

I think it would be an APS constellation, because Martian orbits like Areosynchronous get their prefix from the greek Ares. That would be really cool, I wonder if it would be faster and more precise because there would be negligible human-produced radio noise to interfere and the Martian ionosphere is much thinner, or if it would be worse because the thinner and weaker atmosphere and magnetic field don't protect the…

But the G in the Global Positioning System doesn't stand for Geosynchronous...

Re: Mars helicopter employs advanced control techniques to survive in-flight anomaly

#20

Post by Sharlin »

pilsetnieks wrote: post #19
LeifCarrotson wrote: post #12

Earlier quoted context omitted.

I think it would be an APS constellation, because Martian orbits like Areosynchronous get their prefix from the greek Ares. That would be really cool, I wonder if it would be faster and more precise because there would be negligible human-produced radio noise to interfere and the Martian ionosphere is much thinner, or if it would be worse because the thinner and weaker atmosphere and magnetic field don't protect the…

But the G in the Global Positioning System doesn't stand for Geosynchronous...

Indeed satellite navigation sats aren’t even on geosynchronous orbits.
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