Avions de combat: Boeing passe à l’attaque

Sur le même sujet

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  17 juillet 2023 | International, Terrestre

  Plasan to supply armored cab for AM General’s JLTV

  The new deal contributes to solidifying Plasan's footprint in the United States.

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  13 mai 2020 | International, Naval, C4ISR

  Failure to communicate: US Navy seeks faster data transfers amid Arctic ice

  Andrew Eversden WASHINGTON — Research in the Arctic Ocean is no small feat. The area can prove inaccessible at times, and sensors can fail to communicate data from under the ice or get crushed by slabs of ice. But with the Arctic getting warmer and ice melting at an accelerated rate, the U.S. Navy is preparing to operate in newly available waterways. To do that effectively, the service knows it will take intense research to create durable, innovative solutions that can withstand harsh conditions, while also relaying data to researchers. “If the Navy's thinking about having to run operations up there with submarines, surface vessels and aircraft, you really need to understand that operational environment,” Scott Harper, the Office of Naval Research's program manager for Arctic and global prediction, told Defense News in a May 4 interview. “Where is that sea ice and how quickly is it retreating? And what is it doing to the upper water column in the ocean? "To really understand all that, you need to have a lot of observations.” Navy and academic researchers are working together to improve the service's forecasting models in the Arctic. The Navy currently has research buoys, sensors and other technology floating in the water to track a variety of metrics: waves, atmospheric and water circulation, sea ice thickness and cover, speed at which the ice moves, and several other factors. All those metrics factor into Arctic forecasting. In order to improve its forecasting capabilities, the Navy needs to improve its numerical models, or complex equations used in predictions. But to do that, the service needs more up-to-date data. “These numerical models are kind of like balancing your checkbook,” Harper said. “You need to start with what your current checking account balances [to[ if you're going to predict what it's going to be at the end of the month. And so even if you had a perfect numerical model that you could use to make a forecast, if you don't know what the conditions are right now, you're not going to be able to forecast what the future state is going to be.” To do this, the Navy wants to more quickly collect data through an effort called the Arctic Mobile Observing System, or AMOS. The program aims to create near-real-time data transmission of the sea condition under the ice, and communicate that information to the Navy via satellite. “You have satellites that can look down at the surface of the Arctic Ocean and the sea ice conditions,” Harper said. “But what we don't have [is] the ability to look under the ice and understand what the ocean conditions are, and that's what we're really trying to enable with Arctic Mobile Observing System prototype.” The AMOS program has deployed gliders underneath the sea that are collecting and storing data about the oceanic conditions under the ice, and tracking the location of frozen water using acoustics. In a few months, Harper said, researchers will send an icebreaker to the Arctic and gather the data collected by the gliders. The Office of Naval Resarch, however, would like to bypass the multi-month delay involved in collected the data. To do so, the office plans to enable two-way communication so underwater sensors can communicate data via floating buoys in the ice that, in turn, communicate the data via satellites back to the Naval Oceanographic Office. The project is currently two years into the five-year project. According to the project website, it's slated to end in fiscal 2023 with the recovery and evaluation of the initial prototype in the late summer of 2023. Harper said the project's biggest success has been the navigation system that's currently working underneath the ocean surface. “The fact that we can put sensors out that will know where they are without having to come to the surface to get a GPS fix — because they can't come to the surface because there's sea ice there for nine months out of the year," he said. "That's a big win.” Another critical component to the real-time data collection are the buoys that ultimately must be able to survive the cruel nature of Arctic ice. The AMOS team has deployed prototypes of “ice-hardened” buoys that survived “multiple months” in the Arctic environment, Harper said, paving the way for a fully equipped communications buoy that can talk with underwater sensors. “You can go out there and you can put your sensors in the ice, but a lot of times they'll fail,” Harper said. “And they'll fail because they'll get crushed in the ice or tipped over or toppled by changing ice conditions. And so the ability to deploy a buoy that is robust enough to survive the sea ice is one of the technological hurdles to doing this.” https://www.c4isrnet.com/smr/frozen-pathways/2020/05/11/failure-to-communicate-us-navy-seeks-faster-data-transfers-amid-arctic-ice/

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  29 mai 2023 | International, Aérospatial

  Les pilotes ukrainiens seront formés en Europe pour utiliser les chasseurs américains | Guerre en Ukraine

  Les responsables américains doutent que l’Ukraine puisse utiliser les F-16 dans sa contre-offensive annoncée.