Chi-squared Target Models - General Target Model

General Target Model

Swerling target models give the RCS of a given object using a distribution in the location-scale family of the chi-squared distribution.

p(\sigma) = \frac{m}{\Gamma(m) \sigma_{av}} \left ( \frac{m\sigma}{\sigma_{av}} \right )^{m - 1} e^{-\frac{m\sigma}{\sigma_{av}}} I_{[0,\infty)}(\sigma)

where refers to the mean value of . This is not always easy to determine, as certain objects may be viewed the most frequently from a limited range of angles. For instance, a sea-based radar system is most likely to view a ship from the side, the front, and the back, but never the top or the bottom. is the degree of freedom divided by 2. The degree of freedom used in the chi-squared probability density function is a positive number related to the target model. Values of between 0.3 and 2 have been found to closely approximate certain simple shapes, such as cylinders or cylinders with fins.

Since the ratio of the standard deviation to the mean value of the chi-squared pdf is equal to -1/2, larger values of will result in less fluctuations. If equals infinity, the target's RCS is non-fluctuating.

Read more about this topic:  Chi-squared Target Models

Famous quotes containing the words general, target and/or model:

    “General education is the best preventive of the evils now most dreaded. In the civilized countries of the world, the question is how to distribute most generally and equally the property of the world. As a rule, where education is most general the distribution of property is most general.... As knowledge spreads, wealth spreads. To diffuse knowledge is to diffuse wealth. To give all an equal chance to acquire knowledge is the best and surest way to give all an equal chance to acquire property.”
    —Rutherford Birchard Hayes (1822–1893)

    “Well gentlemen, this is it. This is what we’ve been waiting for. Tonight your target is Tokyo. And you’re gonna play ‘em the Star Spangled Banner with two-ton bombs. All you’ve got to do is to remember what you’ve learned and follow your squadron leaders. They’ll get you in, and they’ll get you out. Any questions? All right that’s all. Good luck to you. Give ‘em hell.”
    —Dudley Nichols (1895–1960)

    “When you model yourself on people, you should try to resemble their good sides.”
    —Molière [Jean Baptiste Poquelin] (1622–1673)