Bias in Triangular Interferometer

In class TriangularInterferometer(InterferometerList): latitude and longitude are computed as

latitude += ( np.arctan( length * np.sin(xarm_azimuth * np.pi / 180) * 1e3 / utils.radius_of_earth ) * 180 / np.pi ) longitude += ( np.arctan( length * np.cos(xarm_azimuth * np.pi / 180) * 1e3 / utils.radius_of_earth ) * 180 / np.pi )

but the longitude should have

/ utils.radius_of_earth * np.cos(latitude*np.pi/180)

instead of just / utils.radius_of_earth, because the "circumference" of the Earth at each latitude is going to be different and not just the equatorial one. If this is not taken into account, the final distance between the triangular detector vertices is going to be biased.