Bistatic range

Bistatic range refers to the basic measurement of range made by a radar or sonar system with separated transmitter and receiver. The receiver measures the time difference of arrival of the signal from the transmitter directly, and via reflection from the target. This defines an ellipse of constant bistatic range, called an iso-range contour, on which the target lies, with foci centred on the transmitter and receiver. If the target is at range Rrx from the receiver and range Rtx from the transmitter, and the receiver and transmitter are a distance L apart, then the bistatic range is Rrx+Rtx-L. Motion of the target causes a rate of change of bistatic range, which results in bistatic Doppler shift.[1][2][3]

Bistatic range geometry

Iso-range contour

Generally speaking, constant bistatic range points draw an ellipsoid with the transmitter and receiver positions as the focal points. The iso-range contours are where the ground slices the ellipsoid. When the ground is flat, this intercept forms an ellipse. Note that except when the two platforms have equal altitude, these ellipses are not centered on the specular point.[4]

gollark: If you use DD/MM/YYYY AutoBotRobot queues your reminder at midnight UTC then, if you use YYYY-MM-DD it uses the current time but the provided date.
gollark: But you do need dates fairly often, and this makes it *consistent* between implementations.
gollark: For example, as well as the time-duration-type thing ("5y2mo3w" etc) it actually supports DD/MM/YYYY as well as some weird backward thing because it uses an external library for it too.
gollark: And even then it still has some weirdness.
gollark: Datetimes are very hard. AutoBotRobot has to do a bunch of stuff to make it do even roughly what people expect.

See also

References

  1. Cherniakov, Mikhail (ed). (2007). Bistatic Radar: Principles and Practice. Wiley. ISBN 0-470-02630-8
  2. Willis, Nicholas. (2007). Bistatic Radar. SciTech Publishing. 2nd ed. ISBN 1-891121-45-6
  3. Willis, Nicholas J.; Griffiths, Hugh D. (2007). Advances in bistatic radar. SciTech Publishing. ISBN 1-891121-48-0.
  4. http://www.dtic.mil/dtic/tr/fulltext/u2/a163941.pdf
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