Meanwhile, a vast majority still use the amateur radio 70cm band to transmit telemetry. One such cubesat is in hot water because it doesn't seem to be following the non-commercial interests regulations.[0]
A laser system would be pretty neat, not having to worry about frequency spectrum requirements and regulations, increasing bandwidth, and reducing cost...until a cloud gets in the way.
How do atmospheric disturbances appear to a system like this?
My naive assumption is that, at the macro scale, you will have a slowly varying snaking path through the atmosphere, causing the beam position on the ground to lazily move about. And, at the smaller scale, turbulence, spread, and flicker within that beam (caustics?).
Atmospheric disturbance was a major problem for the SDI (Star Wars) project.
They came up with solutions, and no doubt there are more and cheaper solutions today, given advances in materials, computing and astrophoto stacking techniques.
Note that they were able to use off-the-shelf tank infrared detectors ($50,000 each) to detect ICBM launches from space, so I suspect even more cross-pollination 35 years later. For example, fiber optics are orders of magnitude better now.
Google established 155mbps connection at about 100km from two free floating balloons in 2016. I was on project and site for this launch, it was very clear morning/day, and atmospheric clarity will certainly affects transmission. These systems are built to recognize and mitigate for expected noise, but I'd imagine atmospheric clarity is always a high-impact variable.
5 comments
[ 2.2 ms ] story [ 20.5 ms ] threadA laser system would be pretty neat, not having to worry about frequency spectrum requirements and regulations, increasing bandwidth, and reducing cost...until a cloud gets in the way.
[0] http://www.amsat.org/pipermail/amsat-bb/2018-December/070833...
My naive assumption is that, at the macro scale, you will have a slowly varying snaking path through the atmosphere, causing the beam position on the ground to lazily move about. And, at the smaller scale, turbulence, spread, and flicker within that beam (caustics?).
Does anyone have some insight?
They came up with solutions, and no doubt there are more and cheaper solutions today, given advances in materials, computing and astrophoto stacking techniques.
Note that they were able to use off-the-shelf tank infrared detectors ($50,000 each) to detect ICBM launches from space, so I suspect even more cross-pollination 35 years later. For example, fiber optics are orders of magnitude better now.