Terrain correction systems

1. A computer-implemented method of processing measured potential field data from a moving platform potential field survey for mapping a field, the method being implemented in a computer comprising a memory in communication with a processor, the method comprising:

inputting, to said processor, said measured potential field data, said measured potential field data comprising data defining a time series of potential field measurements captured by a potential field measurement instrument mounted on a moving platform, each of said measurements having associated data defining positions of said measurements as a function of time;

inputting, to said processor, terrain data defining a spatial variation of terrain surveyed by said potential field survey;

determining, by said processor, time-domain correction data to be applied to said measured potential field data in the time-domain, said determining comprising:

using said terrain data and said associated data defining positions of said measurements as a function of time; and

compensating, by said processor, for a bandwidth of said potential field measuring instrument, wherein said compensating for said bandwidth comprises filtering, by said processor, said time-domain correction data using a filter matched to an impulse response of said instrument; and

adjusting, by said processor, said measured potential field data defining said time series of potential field measurements using said time-domain correction data to provide terrain corrected measured potential field data for said mapping of said field.

2. A method as claimed in claim 1 wherein said determining of said time-domain correction data comprises performing, by said processor, a forward calculation from said terrain data to said time-domain measured potential field data.

3. A method as claimed in claim 1 wherein said time-domain correction data comprises a set of calculated values of said measured potential field due to said terrain at three-dimensional positions in space along survey lines of said potential field survey.

4. A method as claimed in claim 3 wherein said three-dimensional positions comprise positions of said moving platform at regularly spaced intervals in time.

5. A method as claimed in claim 1 wherein said method is implemented off-line, after collection of said measured potential field data using said moving platform.

6. A method as claimed in claim 1 further comprising determining, by said processor, a set of field mapping parameters mapping said field using said terrain corrected measured potential field data.

7. A method as claimed in claim 6 further comprising determining, by said processor, a map of said field using said field mapping parameters.

8. A method as claimed in claim 1 wherein said measured potential field data comprises gravity or gravity gradiometer data.

9. A method as claimed in claim 8 wherein said measured potential field data comprises data for gravity gradient component G zz .

10. A method as claimed in claim 1 wherein said moving platform comprises an aircraft.

11. A carrier having a processor control code thereon that cause said processor to implement the method of claim 1 .

12. A data processing system for processing measured potential field data from a moving platform potential field survey for mapping a field, the system comprising:

data memory for storing measured potential field data, said measured potential field data comprising data defining a time series of potential field measurements captured by a potential field measurement instrument mounted on a moving platform, each of said measurements having associated data defining positions of said measurements as a function of time, and for storing terrain data defining a spatial variation of terrain surveyed by said potential field survey; and

program memory for storing processor control code; and

a processor coupled to said data memory and to said program memory to load and implement said control code, said control code comprising code to cause the processor to:

input, to said processor, said measured potential field data and said associated data for said measurements;

input, to said processor, said terrain data;

determine, by said processor, time-domain correction data to be applied to said measured potential field data in the time-domain, said determining comprising:

using said terrain data and said associated data defining positions of said measurements as a function of time; and

compensating, by said processor, for a bandwidth of said potential field measuring instrument, wherein said compensating for said bandwidth comprises filtering, by said processor, said time-domain correction data using a filter matched to an impulse response of said instrument; and

adjust, by said processor, said measured potential field data defining said time series of potential field measurements using said time-domain correction data to provide terrain corrected measured potential field data for said mapping of said field.

13. A data processing system as claimed in claim 12 wherein said determining of said time-domain correction data includes compensating for a bandwidth of said potential field measuring instrument.