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  • #91
    Originally posted by ancientmariner View Post
    The bottom line for all Naval packages aboard ship is that the derivation of New concepts should come from Naval Sources, or it's allied industries. Such improvements should make the equipped vessel a better fighting platform. We can help out Marine Industry in certain projects but remember we are NOT an adjunct of Industry or it's R&D. There are many out there think the Naval Service is a free platform for their projects.
    It is Government, DoD, DF and NS policy to engage with Irish enterprises and educational institutions.

    It is not as if the "Writer" class are being delivered with BFO kites permanently attached
    Last edited by DeV; 13 February 2017, 19:27.

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    • #92
      KITES and other FOB gadgets.

      Originally posted by DeV View Post
      It is Government, DoD, DF and NS policy to engage with Irish enterprises and educational institutions.

      It is not as if the "Writer" class are being delivered with BFO kites permanently attached
      Yes, Engage where possible for our benefit such as professional equivalency between Service grades and courses run by 3rd level Institutes. Looking at kites ,such as SKYSAILS demo videos, it is clear they are unstable and uncontrollable by nature. They sheer and oscillate from Port to Starboard and back again in the following wind as seen. I do not see how it would also provide a stable electronic observational platform with accurate positional information of distant targets.

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      • #93
        Yep there are a whole variety of issues with the sails, but hey if nothing else, I guess it would be a nice HF antenna

        If they do find their way on to a NS vessel, I'll take a wild guess and say it will ultimately just be for a trade mission to China or the like as a R&D demo - for operational purposes though... just too many issues.

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        • #94
          For a radar to see out 3000 miles or whatever is being claimed a fair bit of watts would be needed to power the system.

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          • #95
            Originally posted by danno View Post
            For a radar to see out 3000 miles or whatever is being claimed a fair bit of watts would be needed to power the system.
            Most likely square miles. Then there's the computer processing required to decipher anything useful from a radar platform that is moving rapidly in 3 axis relative to the platform below and the sweep area of the radar.

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            • #96
              Originally posted by ancientmariner View Post
              Yes, Engage where possible for our benefit such as professional equivalency between Service grades and courses run by 3rd level Institutes. Looking at kites ,such as SKYSAILS demo videos, it is clear they are unstable and uncontrollable by nature. They sheer and oscillate from Port to Starboard and back again in the following wind as seen. I do not see how it would also provide a stable electronic observational platform with accurate positional information of distant targets.
              The figure of 8 that the SkySails kite performs is done deliberately to keep the kite flying in the middle of the power zone. At launch and recovery, the kite is put into 12 o'clock mode where it points straight up until it is flying stably almost directly overhead. If it were to have a radar onboard, you would switch to this mode every few minutes to do a few sweeps and then revert to power mode.

              The system currently being developed will use a much smaller kite, not designed for power which will be stable all of the time and not do figure of 8s. The radar will have a range of 40nm as compared to about 12nm from the mast of a ship. This is limited by the size and power or the radar rather than the height of the platform.

              The point about a warship not wanting to fly a big sign saying "here I am" may be valid in certain scenarios but not when you have a handful of ships searching the vast expanse of the Irish EEZ for needles in a haystack.
              Last edited by Archimedes; 15 February 2017, 12:46.
              Si Vis Pacem, Para Bellum

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              • #97
                Radar horizon and radar range are dependent on the radar antenna height, and crucially the nature and height of the target. For example if radar is at a height of 15metres, then horizon range is 8.5 nm. To achieve 40nm the antenna would have to be at a height of 328metres. If the target in the first case was land at 30metre height then it could be picked up at 8.5nm+12.1nm giving a total of 20.6 nm for the mast based antenna on a normal ship.Assuming a ship with about 9metres height was your target , then an aerial height of 230metres would be required to see it at 40nm ie 6.6 + 33.5 or 40.1 nm. I think all in all, a ship launched drone might be more useful in operational surveillance.

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                • #98
                  Originally posted by ancientmariner View Post
                  Radar horizon and radar range are dependent on the radar antenna height, and crucially the nature and height of the target. For example if radar is at a height of 15metres, then horizon range is 8.5 nm. To achieve 40nm the antenna would have to be at a height of 328metres. If the target in the first case was land at 30metre height then it could be picked up at 8.5nm+12.1nm giving a total of 20.6 nm for the mast based antenna on a normal ship.Assuming a ship with about 9metres height was your target , then an aerial height of 230metres would be required to see it at 40nm ie 6.6 + 33.5 or 40.1 nm. I think all in all, a ship launched drone might be more useful in operational surveillance.
                  Kites don't need to return to the vessel to refuel

                  It isn't the only tool in the box it will/would give the commander more options

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                  • #99
                    as regards processing power - a masthead is not exactly holding still, so the issue is not unique to a kite. Amplitude and frequency may both be higher, but it is a solved problem and the computing power should be easily provided by a modern PC - of the more powerful variety.

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                    • Originally posted by DeV View Post
                      Kites don't need to return to the vessel to refuel

                      It isn't the only tool in the box it will/would give the commander more options
                      Its more a question of what you are actually mounting on the kite. The radar antenna only, the antenna and transceiver, antenna transceiver and signal processor? If its only the former then the losses in 250+ metres of waveguide/coax will be wicked, if the latter then weight becomes an issue and the kite starts to get pretty big.

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                      • I agree and waveguide is a dangerous emitter of rays if it gets damaged or even pinholed. There are problems to be overcome such as curvature of the earth and the true height and distance of the target. Air temperature vis -a-vis ground temperature has an effect on range. Overall some form of air patrol and/or a good ESM, ECM, and ECCM systems fitted aboard ship, will always be useful and give one's ship more freedom of action.
                        Last edited by ancientmariner; 16 February 2017, 18:06.

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                        • Originally posted by Medsailor View Post
                          Its more a question of what you are actually mounting on the kite. The radar antenna only, the antenna and transceiver, antenna transceiver and signal processor? If its only the former then the losses in 250+ metres of waveguide/coax will be wicked, if the latter then weight becomes an issue and the kite starts to get pretty big.
                          Cannot the signal be TX'd to the ship thus avoiding the coax.

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                          • As far as I am aware, the system currently being worked on will use a Simrad 4G radar with an ethernet output that connects to ship via wifi.
                            There are always going to be trade-offs between range, weight and power requirements but that is what they are starting with.
                            Si Vis Pacem, Para Bellum

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                            • a New horizon for Simrad yacht radars with a jump from 200feet low range in harbour to 36nm max range . Will the info be available to everybody with a similar receiver? Cheap at 1995USD but poor definition of targets especially land features. It seems to me this is exploratory technology , untried in an extreme marine naval environment.
                              Last edited by ancientmariner; 18 February 2017, 09:37.

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                              • Originally posted by Medsailor View Post
                                Its more a question of what you are actually mounting on the kite. The radar antenna only, the antenna and transceiver, antenna transceiver and signal processor? If its only the former then the losses in 250+ metres of waveguide/coax will be wicked, if the latter then weight becomes an issue and the kite starts to get pretty big.
                                Since the kite is effing big as it is pulling the ship, this is probably not an issue.

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