Geometrics G-882 User Manual

Geometrics Inc. G-882 Cesium Marine Magnetometer Page
66
At the second depth, let the depth in meters be d2, and the raw reading r2.
The formula for the Scale Factor is:
(d1d2)  (r1r2)
The formula for the Bias is:
(d2r1d1r2)  (r1r2)
You may also use Excel to calculate these values using linear regression. The
advantage here is that you can use more that 2 depths and get a best fit for all
the readings.
Put the actual depths in the first column. Put the raw readings in another
column:
A
B
1
True Depth
Raw Reading
2
1
30
3
5
34
4
30
46
5
6
=INTERCEPT(A2:A4,B2:B4)
7
=SLOPE(A2:A4,B2:B4)
Use the INTERCEPT function to calculate the Bias. Use the SLOPE function to
calculate the Scale Factor. Examples are shown in the table above. For this
example, the Slope (Scale Factor) is 1.875, and the Intercept (Bias) is –56.75.

Geometrics G-882 Specifications

General

Brand	Geometrics
Model	G-882
Category	Marine Equipment
Language	English