Re:Mars Helicopter successfully completed its second flight
by NovemberWhiskey on Thursday April 22, 2021 @05:39PM
(#26908504)
>It looks like Ingenuity uses visual odometry from a downward-facing camera, which is likely to require a lot more processing than something like an STM32 could provide.
I believe that for Ingenuity they are actually doing this in software; but at this point, you can just buy off-the-shelf an optical flow odometry ASIC with a built-in camera and lens system that draws <5mA, fits in a 4x5mm footprint and gives you delta-X and delta-Y.
e.g. https://www.pixart.com/products-detail/108/PAA3905E1-Q
Kinda mind-blowing.
Re:Mars Helicopter successfully completed its second flight
by hoseja on Friday April 23, 2021 @06:13AM
(#26913033)
Is that kind of like optical mouse sensor?
Re:Mars Helicopter successfully completed its second flight
by NovemberWhiskey on Friday April 23, 2021 @02:02PM
(#26917401)
Yes it is! Obviously it's a slightly harder problem if you don't know the distance from the surface and you can't provide your own illumination.
Re:Mars Helicopter successfully completed its second flight
by XorNot on Friday April 23, 2021 @12:18AM
(#26910949)
That's one of those missions I'm actually really hoping I live to see: a whole sequence of launches putting a GPS constellation into orbit around Mars.
In order to navigate safely, especially during takeoff and landing, you need a reasonable idea of your absolute velocity relative to the ground. You can't get that from an IMU (except over very short timescales) because of integration errors. A barometer would work for the vertical axis, but getting the horizontal component is a lot trickier. GPS solves this nicely, especially since velocity can be derived from relative measurements, which are much more accurate than absolute ones.
It looks like Ingenuity uses visual odometry from a downward-facing camera, which is likely to require a lot more processing than something like an STM32 could provide.