Geolocation of emitters using an interferometer array

  1. Hello,

    in a paper about geolocation of emitters using an interferometer array I read such a description about a kind of array:

    Such arrays support locating emitters using some form of triangulation or bearings-only geolocation over several dwells as the satellite moves in its orbit.

    I wonder what triangulation and bearings-only geolocaion mean here. What’s the main principles of these two in geolocation?

    Senmeis
     
  2. jcsd
  3. Baluncore

    Baluncore 3,042
    Science Advisor

    “emitters†of what ?
     
  4. Bobbywhy

    Bobbywhy 1,908
    Gold Member

    senmeis, Welcome to Physics Forums!

    In order to facilitate members here offering useful responses it is important to first provide a reference or link to explain in as much detail as possible exactly what your area of interest is. Otherwise, members will either guess and speculate about your meaning or not respond at all.

    Here's my guess: you are asking about electronic warfare wherein one force tries to locate radio frequency emitters of the opposing force passively, thereby not announcing their presence. See this:

    "Passive Geolocation for Multiple Receivers with No Initial State Estimate"
    http://www.dtic.mil/dtic/tr/fulltext/u2/a400080.pdf

    If you can find your answer in this paper, let us know. If you have any further questions, pleas post them here, making sure you supply enough detailed information.

    Cheers, Bobbywhy
     
  5. Bobbywhy

    Bobbywhy 1,908
    Gold Member

    senmeis, Have you actually read and studied that patent? In claim number 5, the use of interferometer arrays is described in exact detail.

    The method of triangulation and bearings-only geolocation is described in exquisite detail in the article linked in my post number 3.

    If you have some specific questions, please post them here. Physics Forums members are always ready and willing to assist a true “searcherâ€.
     
  6. It really wouldn't matter what it emitted, say sound waves. If so the sensors would just be able to respond to sound of X bandwidth and of course subject to the limitations of that medium. Or emitters of radiation, same thing, the basic triangulation method would work on both of those types, again subject to the limitations of the medium, like radiation getting attenuated in the atmosphere and such. Even RF has those kinds of limitations such as low frequencies not penetrating the ionosphere thus the whole system would be bandwidth limited, only frequencies higher than say 30 mhz would get through the ionosphere if the sensors were in some kind of Earth orbit. That frequency limit would go up and down in frequency depending on what part of the solar cycle we were in att.
     
  7. Baluncore

    Baluncore 3,042
    Science Advisor

    After years of ionospheric prediction, OHR and radio astronomy, I quite understand the subject of ionospheric transparency.

    But it makes a big difference to the time it takes to compile a meaningful answer. I did not have that time. To be helpful we needed more information as is evidenced by Bobbywhy's post.

    The OP asked a question without giving any information about their field of interest or their level of understanding, which makes it more difficult to provide a concise or helpful answer. We now know the question arose from a patent specification. Interestingly, a patent is not a peer reviewed document, so all sorts of vague and wide open claims are made in patents. Maybe this partly explains why there was so little information in the OP.

    Is that millihertz, (mHz), or megahertz, (MHz)?
    Radio astronomy observations using interferometers looking through the ionosphere have been made well below 1 MHz, indeed Grote Reber observed in the 500 kHz to 3 MHz MW band.
     
  8. Thank you for all of your advices. I just want to do a simulation with the concept of this patent for my semester paper. Somehow I find this antenna constellation very interesting, different from the conventional one with X and Y crossing.

    I think this configuration is related to number theory. Maybe I shall read such articles before I can invent a new constellation.

    Senmeis
     
  9. As far as I understand, the six areas on the earth surface in Figure 8C represent ambiguities. Within each area is the so called measurement error area which is determined by the accuracy of the antenna array. Is it correct?

    Senmeis
     
  10. I have read this document. It seems bearings are just angles between connections from emitter to receivers and the x axis.

    This document describes the measurements where at least two separate devices are needed. It is different from the above patent. Do I understand it correctly?

    Senmeis
     
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