$400 Detect and Measure ONLY the Earths Natural Electric Currents Remotely

I need a System Designed that can detect and measure ONLY the Earths Natural Electric Currents Remotely in a given area. That means the system will be able to detect and measure only the electric currents and display the data. It will be able to read all the electric data across a field remotely at a distance up to 5 miles or more. The telluric current frequencies range from .01 Hz to 25,000 Hz. Voltages to be measured are around 500mV. The System design must be hand held size. And yet be very sensitive to collect all the measurements. I Don't want wires in the ground, or cables to place all over the ground. The system must be a Remote System. I need some explaining of the methods you will be using to know you won't be using methods we know will not work. So I will need some explaining to make sure you would be working on sound principles and concepts. Methods Such as: Radar Laser Ground Probes Radio Signals Bounced off of Plates Fiber Optic Sensors I look forward to your comments. So PM me as soon as possible. This is for the design only, not actually building the detector, I will build the detector. See Attached Files for more information.