Method for determining positions of sensor streamers during geophysical surveying

A method for geophysical surveying comprising:

• determining geodetic positions of a plurality of locations along a first geophysical sensor streamer which is towed at a first depth in the body of water;
• causing a lateral offset between the first geophysical sensor streamer and a second geophysical sensor streamer which is towed in the body of water;
• measuring a distance between a point on the second geophysical sensor streamer and each of a first and a second selected points along the first geophysical sensor streamer;
• measuring a second depth at the point on the second geophysical sensor streamer;
• calculating a depth difference from the first depth and the second depth;
• and
• determining a geodetic position at the point on the second geophysical sensor using the depth difference, a direction of the lateral offset and the measured distances;
• actuating at least one geophysical energy source disposed in the body of water;
• and
• detecting geophysical signals with one or more geophysical sensors disposed on at least one of the first and second geophysical sensor streamers.