rdcoupling

Range Doppler coupling

Syntax

  • dr = rdcoupling(fd,slope) example
  • dr = rdcoupling(fd,slope,c)

Description

example

dr = rdcoupling(fd,slope) returns the range offset due to the Doppler shift in a linear frequency modulated signal. For example, the signal can be a linear FM pulse or an FMCW signal. slope is the slope of the linear frequency modulation.

dr = rdcoupling(fd,slope,c) specifies the signal propagation speed.

Examples

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Range of Target After Correcting for Doppler Shift

Calculate the true range of the target for an FMCW waveform that sweeps a band of 3 MHz in 2 ms. The dechirped target return has a beat frequency of 1 kHz. The processing of the target return also indicates a Doppler shift of 100 Hz.

slope = 30e6/2e-3;
fb = 1e3;
fd = 100;
r = beat2range(fb,slope) - rdcoupling(fd,slope);

Input Arguments

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fd — Doppler shiftarray of real numbers

Doppler shift, specified as an array of real numbers.

Data Types: double

slope — Slope of linear frequency modulationnonzero scalar

Slope of linear frequency modulation, specified as a nonzero scalar in hertz per second.

Data Types: double

c — Signal propagation speedspeed of light (default) | positive scalar

Signal propagation speed, specified as a positive scalar in meters per second.

Data Types: double

Output Arguments

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dr — Range offset due to Doppler shiftreal scalar

Range offset due to Doppler shift, returned as an array of real numbers. The dimensions of dr match the dimensions of fd.

More About

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Range Offset

The range offset is the difference between the estimated range and the true range. The difference arises from coupling between the range and Doppler shift.

Algorithms

The function computes -c*fd/(2*slope).

References

[1] Barton, David K. Radar System Analysis and Modeling. Boston: Artech House, 2005.

[2] Richards, M. A. Fundamentals of Radar Signal Processing. New York: McGraw-Hill, 2005.

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