torsdag 1. oktober 2015

Drone - Skal kunne holde seg i lufta i 3 mndr. - RAS


Staying power – UK superdrone targets three 


months aloft

UK's Zephyr 7 holds the ultimate endurance record of 14 days. (Airbus DS)
In 2016 a British-designed and developed superdrone is set to smash its own endurance record by staying airborne for an incredible three months. TIM ROBINSON reports on the next evolution of the record-breaking Airbus Defence and Space Zephyr HAPS (high altitude pseudo satellite).
In a building in the historic centre of British aviation in Farnborough, Airbus Defence and Space (Airbus DS) engineers are putting the finishing touches to an ungainly looking flying vehicle that is set to push the boundaries of aeronautics to the very limit. Called Zephyr 8, this solar-powered electric drone with a 28m massive wingspan could revolutionise persistent surveillance, telecoms and open up unimagined new markets for an aerial vehicle able to do a satellites job but at a fraction of the cost.

Originally developed by the UK's QinetiQ, in 2010 the previous version, the Zephyr 7, set an absolute record for an air vehicle by staying aloft for an amazing 14 days and 14 nights smashing the previous record of 30 hours. Rumour is, that it could have stayed airborne even longer but, after two weeks and having proved their point, the engineers got bored and brought it back to earth. The Zephyr flies at high altitudes to catch the sun's rays at 70,000ft, dipping 5,000ft during the night to save power. It takes four to five hours to spiral up slowly to reach this height.

AirbusDS acquired the project and team from QinetiQ in 2013 and, in 2014, flew the Zephyr 7 for 11 days and 11 nights during winter - an important step in expanding its usefulness for operations in northern and southern latitudes (as a solar-powered drone it cannot fly during when it is night in the Arctic/Antarctic for 24hours). After 900 hours of flying, the Zephyr 7 is set to be retired where it will be displayed in the Science Museum this year alongside other iconic flying machines. But the Zephyr 8 and its follow-on designs are set to push this technology even further.

What is a pseudo satellite?

 
The Zephyr 8 is being built in the cradle of British aviation at Farnborough (Airbus DS)
Airbus has termed this class of drone as HAPS (high altitude pseudo satellite) to draw a distinction between the extreme endurance of Zephyr and other HALE (high altitude long endurance) types such as Global Hawk.

So what is a pseudo satellite? Essentially, by flying at the edge of space (72,000ft), a UAV can loiter for extremely long periods of time. That means it can be used for persistent surveillance, or to boost communications over a certain area, for both military and non-military missions. A single HAPS, for example, can cover a 400mile footprint allowing communications beyond line of sight for those on the ground.

High altitude pseudo satellites (HAPS) have some notable advantages over satellites, too. First, the cost is a the fraction of a satellite and launch mission. Solar-powered, there are no fuel costs either, so operational costs are miniscule. Second, for a LEO satellite tasked with surveillance of a certain area or region, only part of the time will the satellite be over the region of interest - the rest, thanks to orbital physics, will be spent travelling over the rest of the globe. Third, with long-lead launch schedules years in advance and a highly predictable orbit, the pseudo satellite can be more flexible to respond to emerging crises or humanitarian situations where sustained spot coverage is needed immediately. Finally, and perhaps something that will become more important in the future, satellites with an average lifespan of 20-25 years cannot be upgraded in orbit, a distinct limitation when computer and sensors technology evolve so fast. Three month missions then, enable a HAPS to have regular windows where it could be modified, new payloads put on, or batteries added. Indeed, the Zephyr 8 is designed with a modular payload package to allow it to be easily upgraded.

It is also worth noting that in the 'near space' environment of 70,000ft the issues of 'sense and avoid' (currently a major obstacle to opening up lower tiers of airspace to unmanned aircraft to share with manned aircraft) disappear entirely. Airbus says that this means that the HAPS neatly fits a gap between traditional UAVs, limited by airspace (and also weather) and space-based systems.

Bleeding edge technology

Zephyr 7 landing. It is hand launched with a three person crew to support the wings. (AirbusDS)
Key to the Zephyr 8's incredible performance is its extreme light weight (at 55kg it is 40% lighter than the Zephyr 7) and its increased lithium sulphate battery efficiency (30% more powerful than the previous model and the 'best in the world‘, according to AirbusDS). Indeed such is its improved performance, AirbusDS says that the three months endurance is not a hard limit but includes a safety margin too.

Another key advance is its aerodynamics, particularly its specially-shaped patented wingtips for high altitude flight which were inspired by a bird's wings. Sadly the designer of Zephyr, an aerobatic pilot, engineer and aerodynamic expert Chris Kelleher, recently passed away. His genius though, lives on in his record-breaking design.

Finally, another technical advance is its ultra-thin, ultralight state-of-the-art solar panels. All told, this means that propulsion efficiency for this superdrone is 98%.

Next gen eternal flight

Could the Zephyr/Z350 be equipped with large antenna arrays like China's stealth hunting Divine Eagle?
But Airbus does not plan to stop with the Zephyr 8. Although the Zephyr name may be dropped for the next variants, two more generations are planned (notionally called 'Z350' at the moment). Generation 1 and Generation 2 will lift the payload capability from the Zephyr 8's 5kg to 20kg and then 40kg respectively, while also adding more power (the Gen 2 would have 1 kilowatt). This will open up heavier, more capable payloads, such as more sophisticated IR/EO sensors or advanced radars.

Indeed, speaking at a pre-DSEI briefing, Steve Whitby, HAPS Business Development, at AirbusDS revealed that the hollow structure and its long 35m wingspan would open up possibilities of fitting phased array radar modules to turn the drone into a giant radar antenna. This could conceivably provide an unmanned AWACS-type platform equipped with a sensitive radar the capability to detect stealth and LO aircraft, missiles or drones. Networking two such AESA-equipped drones together would provide an even more capable counter-stealth capability. China, for example, is already working on a stealth hunting radar UAV, (Divine Eagle) but, as such, there is no such equivalent drone yet in the West.

Finally, it also has to be noted that although the Zephyr is not a dedicated stealth drone, it is, thanks to its ultra lightweight construction, 'difficult to find in the skies', according to Airbus. Once airborne and at 70,000ft it thus would be able to throw off many interested parties as to where it was actually going and what it was looking at.

Airbus is now in detailed design and wind-tunnel tests of the next gen 'Z350' Gen 1, with a plan to fly this future variant at the "back end of 2017" according to Whitby.

Increasing customer interest

Future models of the Zephyr could be put into production at Airbus' wing centre of excellence at Broughton. (AirbusDS)
The Zephyr 7 has already been trialled by the UK MoD and by unnamed US government customers. Having proved the technology, the current Zephyr 8 is now attracting wider interest. The UK MoD is planning to acquire three Zephyr 8s as part of an operational capability demonstration. If it goes ahead, the MoD will also fly two of these together at the same time – a feature possible thanks to the Zephyr GCS which allows an operator to fly up to four simultaneously. (At 70,000ft there is no other air traffic to deconflict with, leading to a very low workload for the pilots). Flying two simultaneously also opens up interesting missions – using both as data relays, or one as a sensor and the other as an airborne relay to pass video and/or images to ground commanders.

There is also significant international interest now developing in Zephyr and its follow-on. As well as trials with unnamed US DoD customers, Airbus revealed it is in discussions with both Singapore and Germany for HAPS studies. German police and military, for example, are interested in it as a communications relay (imagine it boosting radio coverage during a public event such as the Olympics). Meanwhile, the Singaporean Navy see potential in the Zephyr as a HAPS maritime patrol platform with a dedicated radar. This would see the Zephyr launched (and possibly recovered too) from a large barge.
However, in a clarification to the press, AirbusDS is at pains to make clear that it is still early days yet and nothing has been signed. "We have ambitions, and are expecting to secure contracts for Zephyr in the near future. But no contracts are in place with the UK MoD, or Singapore or Germany." it said.
In a further twist, the MoD also distanced itself from Zephyr and firm contracts with Airbus DS saying to industry publication Defense News:"The situation is that no decisions have been taken as to whether the MoD is intending to investigate the military utility of High-Altitude Pseudo Satellites.” This contradicts much talk and hints about UAVs being an integral part of the UK's next generation ISTAR capability.  In particular, the UK's Project Scavenger UAV requirement for deep and persistent ISR beyond what the Reaper can offer, is still unfulfilled. Indeed, the MoD's own in-house magazine for its procurement arm, DES&S, in its August 2015 issue revealed there is an official follow-on project from Zephyr 7, saying "Technology Office are leading the next phase, an Operational Capability Demonstration".
Reading between the lines then, this briefing may have stolen some of the MoD's thunder for a possible 'game changing' technology to be used by British Forces' story to accompany the upcoming SDSR - set to be released before the end of this year .

Military customers (whether in denial or not) are only one half of potential HAPS sales. With Facebook and Google also working on similar pseudo satellite technology (indeed, Facebook's Aquila is also being built in the UK) there is also strong interest from civil customers for low-cost persistent surveillance, communication relay or internet applications. AirbusDS, for example, has already received interest for commercial organisations interested in this game-changing HAPS – including in the US, who see it as a platform for precision agriculture.

Interestingly, Whitby also revealed that Airbus is now looking at sites for mass production of Zephyr UAVs with one of the potential locations being the UK's Broughton factory. With expertise in building advanced, high efficiency wings – Broughton would seem a natural fit.

Summary

Flying the flag - the UK leads the world in this technology.
The Zephyr 8, and its follow-on models are significant, not only for the cutting edge technology, aerodynamics and disruptive capability they could offer, but also of huge export potential and a British drone that currently leads the world. While Europe frets over US and Israeli MALE UAVs dominating the marketplace, Zephyr provides a UK-developed aerospace technology that is ahead of anyone else. In 2016, if it flies for three months it will pull even further ahead of potential competitors.

In the immortal words of Roger Moore's James Bond: if you want to know what the Zephyr is doing for UK aeronautical innovation it is: "keeping the British end up, sir". For ultra long endurance drone flight - 'nobody does it better' than Zephyr.
- See more at: http://aerosociety.com/News/Insight-Blog/3570/Staying-power-UK-superdrone-targets-three-months-aloft#sthash.E5dJ32JV.dpuf

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