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Method: porbits

The frequency shift $ \Delta f$ between the master and slave range data spectra equals

$\displaystyle \Delta f = -\frac{c}{\lambda} \frac{{B_{\perp}}}{r_1\tan(\theta-\...
...ta-\alpha)} \approx -\frac{c}{\lambda} \frac{\Delta\theta}{\tan(\theta-\alpha)}$ (V1)

Where:
$ \Delta\theta = \theta_1-\theta_2$, $ \alpha$ is the local terrain slope w.r.t. the ellipsoid, $ c$ is the speed of light, $ \theta $ is the local incidence angle (!), $ \lambda$ is the radar wavelength, $ r_1$ is the slant range ground to master. The approximation is used in Doris. Of course, the sign of $ {B_{\perp}}$, or $ \Delta\theta$ is important to filter the correct side of the spectra. Note that

$\displaystyle \alpha \rightarrow 23\ensuremath{^\circ}\Leftrightarrow \Delta f \rightarrow \infty$ (V2)

The local incidence angle is computed with the dot product of vectors P, and P-M. See also [5].

The algorithm in Doris works as


next up previous contents
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Leijen 2009-04-14