Recent content by Unconscious

  1. U

    I Noise Whiteness hypothesis in Kalman filtering

    This is clear to me, thank you. What is not clear to me is the pure math, in particular the step highlighted in my last post. So, are you saying to me that if the noise is not white, then I can’t correctly write the equality ##p(x_k|x_{k-1})=\mathcal{N}(f(x_{k-1}),Q)##? In other words, this...
  2. U

    I Noise Whiteness hypothesis in Kalman filtering

    Thank you for the link, but unfortunately I have not found an answer in that pages. Anyway, I try to share with you my doubt more precisely. Let's consider the formulas in Fig. 1 in this article: https://arxiv.org/pdf/1712.01406.pdf These two formulas have been obtained without assumptions on...
  3. U

    I Noise Whiteness hypothesis in Kalman filtering

    In Kalman filter mathematical treatment I have always read that a foundamental hypothesis is represented by the whiteness of the process noise. I have tried to do again the mathematical steps in the Kalman filter derivation but I can't see where such hypothesis is crucial. Could you help me...
  4. U

    I Limit of limits of linear combinations of indicator functions

    I mean pointwise convergence, optionally except on a measure-zero set of ##\mathbb{R}^n##.
  5. U

    I Limit of limits of linear combinations of indicator functions

    I have a sequence of functions ##0\leq f_1\leq f_2\leq ... \leq f_n \leq ...##, each one defined in ##\mathbb{R}^n## with values in ##\mathbb{R}##. I have also that ##f_n\uparrow f##. Every ##f_i## is the limit (almost everywhere) of "step" functions, that is a linear combination of rectangles...
  6. U

    B Physical temperature and antenna temperature

    Thank you, I will read again with this in mind. Surely, I will come with other questions.
  7. U

    B Physical temperature and antenna temperature

    I have read some documents on the subject, but until now, unfortunately, I still do not have a good understanding of them, most likely due to personal shortcomings that start from physics. In this regard, I would like to try here to expose some doubts that will almost certainly appear very...
  8. U

    Circular antenna array formula

    I had no intention of being rude, I was just exposing my thoughts trying to argue it as best as possible. I am sorry to have offended you. Thank you for the time you have dedicated to me.
  9. U

    Circular antenna array formula

    I set up the problem this way because I followed the path my antenna book taught me, but it only set the problem for arrays whose source distributions do not rotate (which would be like I did in post #8). In the last equation there is no change of integration variables. There, it was only used...
  10. U

    Circular antenna array formula

    Could I ask you where you see logic errors, please? Is there a particular step in my analysis in the first/last message that is wrong?
  11. U

    Circular antenna array formula

    The linked pdf is an extract of the second chapter of the book 'Conformal array antenna theory and design' of IEEE Press. Yes, it's true, in fact I said that this other equation is not applicable to our case: ##\mathbf{A}(\mathbf{r})=\sum_n\mathbf{A}^{(n)}(\mathbf{r})=\frac{e^{-jkr}}{4\pi...
  12. U

    Circular antenna array formula

    It is precisely this formula that cannot be applied to my case, because when you write ##(\mathbf{r}'-\Delta\mathbf{r}_n)## you are actually schematizing a generic array where, however, the elements are obtained using only and solely rigid translations of a reference element: this is not the...
  13. U

    Circular antenna array formula

    No, the element factor has to come up naturally from my first formula, just as it actually did, as you can see from the last formula I wrote. It is not so, in my first expression there is ##\mathbf{J}(\mathbf{r}')##, the whole ##\mathbf{J}(\mathbf{r}')##, which contains everything, it is not...
  14. U

    I Finding a limit involving Chebyshev polynomials

    Solution: https://en.wikipedia.org/wiki/Stolz%E2%80%93Ces%C3%A0ro_theorem .
  15. U

    Circular antenna array formula

    At page 20 of this pdf the two formulas that characterize the behavior of a linear and a circular antenna array are compared. The reason why I write this post is: I don't understand why the second formula is true. Below I show why I am not convinced. In general, given a configuration of sources...
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