SphericalLogIrrCovariance

MATLAB

[BlnX, BlnY] = SphericalLogIrrCovariance(alpha, d, Atm, wvl, [type])

Description

Computes the large and small scale log-irradiance covariance for a spherical wave given turbulence multiplier alpha, point spacings d, atmospheric modeling data in Atm, and wavelength in wvl. In this calculation, the light propagates from the platform to the target.

Parameters

Parameters	Description
alpha [scalar]	Turbulence strength multiplier.
d [vector]	Separation of the points in the irradiance profile (m)
Atm [struct]	Atmospheric modeling structure from AtmStruct.
wvl [scalar]	Optical wavelength (m).
type [string]	(Optional) Scale of covariance to output if the number of outputs is one. Ignored for two outputs. Specify 'large' (default), 'small', or 'both' for combined.

Return Values

Return Values	Description
BlnX [vector]	Large scale log-irradiance covariance value
BlnY [vector]	Small scale log-irradiance covariance value

References

L. C. Andrews and R. L. Phillips, Laser Beam Propagation through Random Media, 2nd ed. Bellingham, Wash.: SPIE Press, 2005.
L. C. Andrews, R. L. Phillips, and C. Y. Hopen, Laser Beam Scintillation with Applications. Bellingham, WA: SPIE, 2001.
L. C. Andrews, R. L. Phillips, and C. Young Hopen, "Scintillation model for a satellite communication link at large zenith angles", Opt. Eng., vol. 39(12), pp. 3272-3280, 2000.

Examples

>> Atm = AtmStruct(0, 2e4, 0, 100, 'Cn2', 'HV57');

>> wvl = 0.5e-6;

>> d = [1 2 3 4 5].*0.02; % points separated by 2 cm

>> [BlnX, BlnY] = SphericalLogIrrCovariance(1, d, Atm, wvl);

Large scale (BlnX) and small scale (BlnY) log irradiance covariance. The irradiance covariances are: BX = (exp(BlnX) - 1) is the large scale irradiance covariance BY = (exp(BlnY) - 1) is the small scale irradiance covariance B = (exp(BlnX + BlnY) - 1) is the full irradiance covariance