Patent ID: 7167005

Claim:
A system, comprising: a transmitter which forms part of an inground portion of the system including a transmitting section having an input and configured for emitting a dipole field signal in response to a voltage at its input, and a power providing section including a battery for producing a battery voltage having a strength that decays with time and a voltage controlled regulator connected to receive said battery voltage for use in providing a supply voltage at the input of said transmitting section such that the transmitting section emits said dipole field signal in a particular way; and a receiver for receiving said dipole field signal and configured for storing a proportionality constant, that relates a depth of the transmitter to an inverse cubic root of the dipole field signal, for use in combination with said proportionality constant by the receiver to determine the depth of the transmitter relative to the receiver, wherein said supply voltage is sufficiently regulated by said regulator to cause the dipole field signal to be emitted in said particular way such that use of the proportionality constant by the receiver results in a determination of the depth of the transmitter, independent of changes in said strength of said battery so long as the battery remains operable, whereby the frequency with which the proportionality constant must be re-determined is reduced from what would be required without the sufficient regulation of said supply voltage by said regulator.