TABLE OF CONTENTS The formula to be used for correcting for true north is
where
| bearing_true (n) | = the target bearing from the ship with respect to true north. |
| ships_heading | = the ship's heading as measured by the ship's Inertial Navigation System or a magnetic compass. |
| Relative_bearing (n) | = the current target bearing relative to ship's longitudinal axis starting at the bow for zero degrees relative and rotating clockwise. |
The formula to be used for correcting from true north to magnetic north is
where
| bearing_mag(n) | = the target bearing from the ship with respect to magnetic north. |
| bearing_true(n) | = the target bearing from the ship with respect to true north. |
| magnetic_variation | = the variation between magnetic north and true north. Magnetic variation may be plus or minus. |
For an interferometer to have no phase ambiguities, the spacing between the antennas should be less than ?/(2 ?) wavelength apart. This provides a phase gain of less than 1. Note that a phase gain of exactly 1 gives a one-to-one conversion from azimuth angle to electrical angle. Therefore, there are no phase ambiguities. If the separation is greater than 1 wavelength, giving a greater than 1 phase gain, then ambiguities exist. For example, if the separation is 2 ?, then half the circle covers 360 degrees and then repeats for the second half of the circle. Therefore, a phase measurement of 40 degrees could be two spacial positions.
