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Shuttle Radar Topography Mission Data
SubtleNuance writes: "This story on Canada.com describes the mission and results of NASA's recent flight to map Earth. The Shuttle trip has provided the most detailed 3D photos of Earth ever released." Some of the images are just astounding. Too bad most of the data isn't available yet.
here
Since Landsat (the image that is overlaid on the radar data) is typically 30m, these data sets won't be any better than that. If I recall, the shuttle X-band only did 100m DEM post spacing (or maybe it was 150m) with a vertical RMS in the 20m range, er, something like that.
There are at least two commercial terrain mapping radar systems out there that can do much better. Star3i (formerly IFSARE) is now operated by Intermap (www.intermap.ca) and does 2.5m postings (Intermap may claim it does better, but I don't believe it). And, there is a new system that is currently being calibrated and may be producing data soon. In addition to X-band, GeoSAR has a P-band capability to "see" through trees, very cool (www.geosar.com).
NULL
Actually, the original SRTM was flown back in 1994 (SIR-C and X-SAR) in an effort to update the military's DEMs. I never did hear what happened to that data (probably secret at the time). You can read a bit about it here:
http://www.jpl.nasa.gov/srtm/spareparts.html
NULL
Umm... I designed and built some of the hardware for SIR-C (and also SRTM). There was absolutely no military connection to SIR-C. And X-SAR was built by the European space agencies, primarily the Italians on the antenna, and the Germans on the digital hardware, and they also had no military connection. The US military only got involved in SRTM after they saw how well the SIR-C radar worked, and after some of the SIR-C folks went looking for money to upgrade SIR-C to SRTM.
SIR-C did not make topographic maps, except for one or two special tests using a technique called "repeat pass interferometry", because it did not have the outboard antenna on the 60M mast that SRTM had, and which gave SRTM its "stereo vision". And SIR-C only imaged a few small strips of the earth, each specifically requested by a scientist for some research purpose, or of course a few strips taken for PR purposes. SIR-C did not attempt to make a global map. This data is in the hands of the scientists involved, who supposedly continue to turn out papers based on the data. Also, SIR-C was conceived as a technology test experiment (and is also referred to as SRL - Space Radar Laboratory), used to test a variety of new radar technologies to see how well they worked from a spacebased platform.