R2R Gravity data product format
#ISO_time UNIX_time longitude latitude raw_gravity dnv_flag gravity_anomaly_pre_eotvos eotvos_corrected_grav FINAL_MEDIAN_FILTERED_GRAV eotvos_correction eotvos_gradient velocity_east velocity course_made_good

ISO_time
 - Time in standard ISO format, e.g 2012-01-11T08:37:23.000Z

UNIX_time
 - Number of seconds since the Unix epoch

Longitude/Latitude
 - Values for longitude and latitude in decimal degrees from -90 to 90 (lat) and -180 to 180 (lon)

raw_gravity
 - Value of raw gravity after bias and scale have been accounted for.

dnv_flag
 - The DNV number propagated from the raw grav file.
    00 - No DNV
    01 - Platform DNV
    02 - Instrument DNV

gravity_anomaly_pre_eotvos
 - The raw_gravity value with theoretical gravity removed and gaussian filter applied

eotvos_corrected_grav
 - The gravity_anomaly_pre_eotvos value with Eotvos correction applied

final_median_filtered_grav
 - The final anomaly.  This is the eotvos_corrected_grav value after a median filter has been applied.

eotvos_correction
 - The value of the Gaussian filtered Eotvos correction applied to the data.

eotvos_gradient
 - The derivative of the Gaussian filtered Eotvos correction used for cutting turns from data.

velocity_east
 - The eastern component of velocity over ground for calculating the Eotvos correction

velocity
 - The velocity over ground for calculating the Eotvos correction

course_made_good
- The value of course made good calculated by R2R.