low cost device to measure Geomagnetically induced current at substations

I am currently working on building a low cost device that is able to measure Geomagnetically induced currents using off the shelf components. I want to use a hall effect sensor to measure current at a transformer neutral, filter the current that is between 0.001-0.1 Hz, store the data on a memory card and eventually send it to a central computer/ internet via GPS.

I am not very familiar with the Arduino and I am wondering if the arduino is capable of filtering, storing and sending data using GPS ?

Any help will be highly appreciated.

How much current flow in Geomagnetically induced currents?
I'm thinking you'll need some signal amplification before you sample the signal and try to detect a very low frequency.
Storing to SD card, that's just data logging. Sending a file over internet is also straightforward, you can browse & find lots of hits on both.
Not sure how GPS fits in there. Aren't the sensors pretty stationary?

GPS = Global Positioning Satellite (receiver). I think you mean GPRS (A cell phone signal).

@Chagrin, thanks for the correction I meant to say GPRS. @CrossRoads , the current magnitude to be measured can go as high as 10 A. I looked at the Arduino GSM/GPRS shield which is able to post to a Google Spreadsheet but I am not sure if it is able to filter and sample the data at a specific rate. I want the cost of the device to be as low as possible without compromising the accuracy of the data.

so I would like to use one board to do all the processing or am I looking at this the wrong way ?

the current magnitude to be measured can go as high as 10 A.

In what sort of conductor will you measuring currents that high, and how often do you expect to see such currents?

Note that "space weather" storms can induce hundred ampere currents in long power lines and pipes, so if you are expecting to observe 10 ampere currents, you should plan for much higher currents as well.

I suspect a split-core DC hall sensor module is used, if you can find a ratiometric 5V one that
would be the ideal match.

You probably want to provide an LC filtered version of 5V to the sensor and AREF and use
analogReference (EXTERNAL), for minimum analog noise.

Is 10 bit ADC enough? If not an external ADC will be needed.

Presumably you need to notch-filter out the mains frequency (and harmonics?)? Some
digital filtering will be needed and careful choice of sampling rate and anti-aliasing input