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ESA Sentinel-1D delivers first high-resolution images
- arghandugh 11mo ago[flagged]
- nuevo_hack 11mo agoThe EU tends to do very well in earth observations compared to the U.S. as some would say they are overall better. A lot of earth science and climate related fields tend to do better in the EU as well. For example, hurricane models tend to outperform their U.S. counterparts.
- mistrial9 11mo agoEU Weather models make a regular appearance on fancy TV KPIX weather show
- 2standards 11mo agotypical content that totally passes the moderation guidelines and community voting
- arghandugh 11mo agoYes, because it’s correct and informative and on-topic. What’s your track record, {1 comment, 0 posts, account 4 hours old}?
- whitehexagon 11mo agoI used to enjoy clicking through to the ESA Sentinel images, but then they kinda dried up for a while, or it was very hit and miss for updates. It would be nice to have regular daily or weekly upload. Our planet is so beautiful, as many of these Sentinel images show.
- saubeidl 11mo agoWhile we're talking about cool ESA achievements, the view of our universe Euclid gives us is incredible. Check out this video they made if you want your mind blown: https://www.youtube.com/watch?v=rXCBFlIpvfQ https://www.youtube.com/watch?v=rXCBFlIpvfQ
- hermitcrab 11mo agoPretty cool. But it gives me some sort of existential vertigo.
- hak8or 11mo agoI was curious what instruments this use, looks like a special form of radar? Does this mean it effectively gives us very accurate height maps regardless of cloud coverage, and is able to differentiate between what surface material it's seeing? > Radar instruments can image Earth’s surface through clouds, precipitation, regardless of sunlight, making them particularly well suited for monitoring polar regions. The Sentinel-1C and -1D satellites also carry an Automatic Identification System (AIS) instrument – improving the mission capacity to detect ships and sea pollution. The Sentinel-1D AIS was also activated as the satellite passed over Antarctica capturing the presence of ships in these extreme areas.
- lmc 11mo agoWhat you can get in a single image are 5.5cm wavelength microwave backscatter - this means surface materials can be differentiated by looking at texture differences at that scale. So - tarmac vs a ploughed field, for example. There's 2 polarizations as well, so you can identify e.g. vegetated areas also, which scatter the signal in a different way. A single image from Sentinel-1 won't give a height map directly, but a pair can using interferometry (InSAR), as the phase of the backscattered signal is also measured. With that you can derive something about the terrain. It's not super accurate though for absolute height maps. And yes the signals pass through cloud and it works at night.
- itishappy 11mo agoIf my understanding is correct (and I'd love to be corrected if not!), it can be used to generate super accurate differential heightmaps. It won't tell you exactly how high a peak is, for example, but it can tell you that it's dropped a few millimeters since the last time you measured. https://en.wikipedia.org/wiki/Interferometric_synthetic-aperture_radar https://en.wikipedia.org/wiki/Interferometric_synthetic-aper...
- lmc 11mo agoTypically you will get an image pair for an area every 6-12 days. The phase used in interferometry is massively affected by atmospheric conditions, which can vary a lot in this time, and are difficult to correct for. So, one pair is often not enough for this. But if you look at a bunch of pairs for that area over a longer time period, you might be able to correct for the atmospheric effects and get your differential height map. You can get more accurate elevation models 'out of the box' with different systems, e.g., the SRTM (one of the most well known publicly available global elevation maps) [1] was made with insar but 2 antennas on one craft, and Germany's TanDEM-X [2] is a pair of satellites flying in formation a few hundred meters apart, capturing the same area at the same time. [1]: https://www.earthdata.nasa.gov/data/instruments/srtm https://www.earthdata.nasa.gov/data/instruments/srtm [2]: https://en.wikipedia.org/wiki/TanDEM-X https://en.wikipedia.org/wiki/TanDEM-X
- mkl 11mo agoHigh resolution images, but they decided to disable zoom on mobile. I don't understand why anyone does that.
- literalAardvark 11mo agoAll of modern web design is about removing as much freedom from html as possible. It's infuriating. We had zoomable, downloadable images in the 90s, with bandwidth as the only constraint. Now I've got 50x as many pixels and I'm forced to use a bookmarklet and 2 menus to be able to see it larger than my fingernail.
- magicalhippo 11mo agoAlso, I don't understand why browsers don't let me override that.
- petee 11mo agoOpera Mobile has a force-allow-zoom option
- magicalhippo 11mo agoIf only Opera was still Norwegian...
- mkl 11mo agoThese replies prompted me to go looking. Firefox Android (which I'm using) does have an option in the settings under Accessibility called "Zoom on all websites". It works! Chrome has a similar option, which also works on this site. I expect this might break a few pages, but Google Maps and OpenStreetMap work fine, with pinch zoom zooming the map when you do it on the map.
- magicalhippo 11mo agoAwesome. Somehow I've missed them introducing that, as a long-time Firefox Android user. And frankly it's in the wrong place if you ask me.
- deleted 11mo ago[deleted]
- cess11 11mo agoThe Copernicus data browser is quite nice, even though they like to sit on possibly sensitive images for long periods of time. https://dataspace.copernicus.eu/browser/ https://dataspace.copernicus.eu/browser/
- transpute 11mo ago"SARLink: Satellite Backscatter Connectivity using Synthetic Aperture Radar" (2024), https://arxiv.org/abs/2402.09682 https://arxiv.org/abs/2402.09682 SARLink is a passive satellite backscatter communication system that uses existing spaceborne synthetic aperture radar (SAR) imaging satellites to provide connectivity in remote regions .. As the first technique for passively sending information bits from the ground to a SAR satellite — and with some SAR systems offering open-access data — this system could enable anyone to send information without expensive licenses or subscriptions. Thus, it provides an accessible way of sending messages in areas without connectivity or in censored environments where active radio transmissions cannot be used. Furthermore, SARLink requires no modification of the satellite infrastructure.. We demonstrate our system using the European Space Agency (ESA) satellite Sentinel-1A, as the data is freely available and the system regularly images all the land on Earth .. a 5.5 ft by 5.5 ft modulating corner reflector could send 60 bits every satellite pass, enough to support low bandwidth sensor data and messages.
- Peteragain 11mo agoCool!
- OgsyedIE 11mo agoIs there a specific name for the vaguely fractal nature of the cliff formations in the Tierra del Fuego shot?
- mynegation 11mo agoFjords?
- itishappy 11mo agohttps://en.wikipedia.org/wiki/Coastline_paradox https://en.wikipedia.org/wiki/Coastline_paradox
- deleted 11mo ago[deleted]
- fuoqi 11mo agoI wonder if China has a constellation of similar satellites with the primary function to track the US CVBGs and provide aiming info for their "carrier killer" systems.