Crossover Analysis

Crossover analysis compares depth or height measurements where two survey or altimeter tracks intersect, using the difference at each crossing to quantify and correct systematic error. In bathymetry it reveals residual heave, tide, sound-velocity, and draft errors as a depth misclosure at line intersections; the statistics of these misclosures gauge internal consistency and feed bias adjustment. In satellite altimetry, crossover differences between ascending and descending passes calibrate orbit and sea-state corrections. A small, zero-mean crossover spread indicates a well-controlled survey; a depth-dependent or track-dependent pattern points to an uncorrected systematic term checked against IHO S-44.