NASA Overcomes Military's GPS Tweaks To Peer Inside Hurricanes (sciencemag.org) 53
sciencehabit shares a report from Science Magazine: A constellation of eight microsatellites has harvested data that -- if folded into the National Oceanic and Atmospheric Administration's (NOAA's) weather models -- could have sharpened forecasts of several recent hurricanes, including Michael, a category-5 storm in October 2018. But progress was hard-won for scientists on NASA's $157 million Cyclone Global Navigation Satellite System (CYGNSS), who discussed early results at a meeting last week, just as another Atlantic hurricane season kicked off. With its flotilla of satellites crisscrossing the tropical oceans, CYGNSS can see through the thick clouds of cyclones. The satellites collect radio signals beamed from standard GPS beacons after they bounce off the ocean's surface. The reflections are influenced by sea's roughness, which depends on wind speed. But a month after launch in December 2016, the team noticed the GPS signals were wavering.
The U.S. military runs the GPS system, and in January 2017, it began to boost the radio power on 10 of its GPS satellites as they passed over a broad region centered on northern Syria. The power boosts, which can thwart jamming, have recurred without warning, each lasting several hours. The swings don't interfere with other scientific uses of GPS. But they threw off the constellation's measurements of high winds by 5 meters a second or more -- the difference between a category-2 and category-3 hurricane. After 2 years of work, the CYGNSS team has compensated by reprogramming its satellites on the fly. The satellites carry large antennas to catch reflected GPS signals, but they also have small antennas that receive direct GPS signals, for tracking time and location. The team repurposed the small antennas to measure the signal strength of the GPS satellites, making it possible to correct the wind speed measures
The U.S. military runs the GPS system, and in January 2017, it began to boost the radio power on 10 of its GPS satellites as they passed over a broad region centered on northern Syria. The power boosts, which can thwart jamming, have recurred without warning, each lasting several hours. The swings don't interfere with other scientific uses of GPS. But they threw off the constellation's measurements of high winds by 5 meters a second or more -- the difference between a category-2 and category-3 hurricane. After 2 years of work, the CYGNSS team has compensated by reprogramming its satellites on the fly. The satellites carry large antennas to catch reflected GPS signals, but they also have small antennas that receive direct GPS signals, for tracking time and location. The team repurposed the small antennas to measure the signal strength of the GPS satellites, making it possible to correct the wind speed measures
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Which is why military transmitters sometimes transmit noise when not in use. So that listeners cannot detect the start of a big operation by the number of transmitters suddenly turning on to coordinate the units. The "noise" is of course just like any other encrypted transmission, for those that don't have a key.
To detect military operations, watch out for soldiers, tanks, choppers etc. ;-)
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Who said anything about trying? Do you wait for an enemy to try and shoot you before putting on a bullet proof vest? I will bet you a testicle that this is being done preemptively precisely when a military operation is taking place.
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Yeah, but it's complete bullshit that the Syrians... are diving around with their families on vacation
It's really like that there, anywhere you go you might have to dive for cover, even on vacation!
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So what you are saying is that military equipment that could be used by adversaries to attack the military or US should be given to civilians? F22's for everyone!!!
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I just want some AAA on the roof in case of nosy drones.
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We pay them to do a certain job. In order to do that job, they need to mess with the GPS signal strength. We don't pay them to defer to civilians. We pay them to break other people's stuff, preferably without breaking the stuff we bought them to help them break other peopl's stuff. They are not policemen. They are not social workers.
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They were doing this because other factions operating in the region were testing (and potentially more than testing) latest generation GPS jamming technology and monitoring how it disrupts US forces. Obviously having critical signals jammed in a life theatre was not an acceptable option, which is most likely why these signals were boosted.
Re:Okay.... (Score:5, Interesting)
Adversaries monitor GPS signal strength as evidence of possible impending US missions.
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Why would they flip the power switch before they needed it?
They need it from the time they take off until they are on target. Maybe 10 or 15 minutes. Plenty of time to close the hangar blast doors and get personnel int shelters.
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They don't have shelters that can stop US bombs.
Only a few sites in the world have that.
It takes a lot of work over a long time to reinforce a bunker, and one American bomb to destroy it.
If the enemy is somebody else, firing mortars or rocket artillery at your position, then warning to get in a shelter is useful. If the Americans are coming, going to the shelter is the best way to die. Your choices are to run away, or die. If the US is doing an operation in Syria, local allies are on the ground nearby. If y
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lol, story boils down to "We made a huge oversight and then fixed it"
It's more like: "The source was always a constant output level, and we modified our system when the military decided to make it variable."
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GPS satellites don't "pass over" anything, they are stationary, that's the whole point!
There's nothing more amusing than condescension from someone who is provably wrong [gps.gov].
The government says GPS satellites orbit twice a day at ~20,000 km. Compare to geosync at ~36,000 km.
Plus, think about it: Why would GPS receivers need almanac data if the satellites were geostationary? If that were the case, they would only need ephemeris.
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Non-published interface (Score:2)
Like any hack that uses a non-public interface, it is prone to being broken. Every hacker worth his salt knows this (and has most likely fell victim to it).