Zephyr: A High Altitude Long Endurance Unmanned Air Vehicle ...

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where λ is the wavelength, c is the speed of light and f is the frequency.Substituting the values gives:λ = 29.98cmIn order for the GPS to work correctly, the maximum distance between the groundingplate (or the earth) and the antenna needs to be less than a tenth of the wavelength:Normally the antenna is touching the ground but in case it is not and it is flying on aplane / <strong>Zephyr</strong>, the distance between the antenna and the grounding plate must be lessthan 3cm.If the grounding plate is not a solid piece of material but has gaps in it, for examples amesh, the distance between the gaps must also not be more than a tenth of awavelength, thus the gaps cannot be bigger than 3cm.Finally the antenna should be situated in the centre of the grounding plate, and thelength of the grounding plate should be of a similar length to the wavelength, i.e.30cm (see figure 9).44
GPS antennaGroundingPlateλ/10 (3cm)λ (30cm)Figure 9. Diagram to show the setup of a GPS antenna in order for it to functionproperlyWith this in mind I found that the best place to put my antenna in order for the camerato have a GPS signal was hanging out of the window (I was on the second floor). Thewindow had a metal mesh that could act as a grounding plate.45
Page 1 and 2: Zephyr:A High Altitude Long Enduran
Page 3 and 4: AcknowledgementsI’d like to thank
Page 5 and 6: ContentsChapter 1 - Introduction an
Page 7 and 8: Chapter 1Introduction and Backgroun
Page 9 and 10: 1.1 History of ZephyrZephyr is a li
Page 11 and 12: The Zephyr 5 project continued with
Page 13 and 14: airframe, with the main aim to impr
Page 15 and 16: 1.2 Environmental IssuesDuring the
Page 17 and 18: order to function, they may not thu
Page 19 and 20: 1.2.3 Cosmic RaysCosmic rays are en
Page 21 and 22: wind speeds. This is to ensure that
Page 23 and 24: crystalline silicon cells and can b
Page 25 and 26: which are then insulated. In order
Page 27 and 28: motion of the aircraft including ro
Page 29 and 30: Within the portable cabins the crew
Page 31 and 32: Simple payloads instructions withou
Page 33 and 34: In the event that the wing does not
Page 35 and 36: Graph 4 shows radiosonde density da
Page 37 and 38: 3.2 NIOSH Lifting EquationThe hand
Page 39 and 40: Variable Description MultiplierD (c
Page 41 and 42: Using the given values, the corresp
Page 43 and 44: 3.3 Airspeed SensorThe current airs
Page 45: 12VSensorPCBZenerDiodeFigure 8. Dia
Page 48 and 49: 3.4 PayloadThe payload is the carry
Page 52 and 53: 3.5 Angle of Attack SensorThe angle
Page 54 and 55: The magnetic sensor seemed much mor
Page 56 and 57: Chapter 4Angle of Attack Experiment
Page 58 and 59: The sensor was powered using an ext
Page 60 and 61: It has to be noted however, that on
Page 62 and 63: experience the atmospheric conditio
Page 65 and 66: 5.2.1 Aerial PhotographyThe most co
Page 67 and 68: meaning that these cameras can be u
Page 69 and 70: Infoterra have a project called Far
Page 71 and 72: it out for long endurance missions.
Page 73 and 74: Figure 18. QinetiQ’s Zephyr5.4 Co
Page 75 and 76: where it is needed rather than havi
Page 77 and 78: Appendix 3Schematic diagram of the
Page 79 and 80: Appendix 5The results table for the
Page 81 and 82: BibliographyQinetiQ Documents[1] St
Page 83: [19] Encyclopedia Britannica, 2004.

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