Patent ID: 8490717

Claim:
A method for determining an average total magnetic field value during drilling comprising: providing a triaxial vector magnetometer affixed to a drill string subassembly wherein the triaxial vector magnetometer is adapted to measure three orthogonal component magnetic fields; allowing the drill string subassembly to rotate; and determining the average total magnetic field value (B TwR ) during the step of allowing the drill string subassembly to rotate, wherein the total magnetic field value (B TwR ) is computed according to a formula selected from the group consisting of: B TwR = ∑ i = 1 n ⁢ B x i 2 + B y i 2 + B z i 2 n ; B TwR = ∑ i = 1 n ⁢ ( B x i 2 + B y i 2 ) n + ( ∑ i = 1 n ⁢ B z i n ) 2 ; and ∑ i = 1 n ⁢ ( B x i 2 + B y i 2 + B z i 2 ) n , wherein B xi , B yi , and B zi each correspond to one of the three orthogonal component magnetic fields.