Mobile detection device for an evaluation of a depth value from the device to an occluded underground elongate utility line, comprising at least: ▪ a housing, ▪ a first and a second detector unit (2a,2b), placed inside the housing, each comprising at least can air core detection loop (25a,25b) with at least one winding of an electrically conductive material arranged along a first winding plane, and oa corresponding transmitting loop (27a,27b) with at least one winding of an electrically conductive material arranged along a second winding plane, wherein the detection loop (25a,25b) and the corresponding transmitting loop (27a,27b) are arranged contiguous to each other and said first winding plane and second winding plane are parallel, and the first and the second detector units (2a,2b) being arranged with a spacing along a predetermined direction with respect to one another, ▪ at least one excitation coil with a ferrite core adapted to emit an alternating electromagnetic excitation field (Be) of a defined characteristic, which excitation coil is placed inside the housing, arranged with a spacing from the first and second detector units along said predetermined direction, wherein the first detector unit is located between the second detector unit and the excitation coil along the predetermined direction, and arranged in such a way that the sensitivity direction of the detection loops of the first and second detector units(25a,25b) is substantially in line with the field emission direction of the excitation coil, ▪ an electronic signal evaluation unit adapted to detect the utility line according to an electrical signal induced in the detection loops (25a,25b) of the detector units (2a,2b) and to evaluate the depth value according to a difference of the electrical signal in-between the detection loops (25a,25b), and ▪ a compensation unit configured to apply an individual electrical signal to each of the transmitting loops (27a,27b) arranged to establish an individual compensation field (Bta,Btb) by each of the transmitting loops (27a,27b), which individual compensation field (Bta,Btb) is configured to substantially nullify influences of the excitation field (Be) at each of the detection loop (25a,25b); wherein the compensation unit is further configured to simultaneously apply the individual electrical signal to each of the transmitting loops (27a,27b) at both detector units (2a,2b) and to control the applied individual electrical signals in such a way, that a simultaneous nullification at both detector units (2a,2b) is established. ▪ a housing, ▪ a first and a second detector unit (2a,2b), placed inside the housing, each comprising at least can air core detection loop (25a,25b) with at least one winding of an electrically conductive material arranged along a first winding plane, and oa corresponding transmitting loop (27a,27b) with at least one winding of an electrically conductive material arranged along a second winding plane, wherein the detection loop (25a,25b) and the corresponding transmitting loop (27a,27b) are arranged contiguous to each other and said first winding plane and second winding plane are parallel, and the first and the second detector units (2a,2b) being arranged with a spacing along a predetermined direction with respect to one another, can air core detection loop (25a,25b) with at least one winding of an electrically conductive material arranged along a first winding plane, and oa corresponding transmitting loop (27a,27b) with at least one winding of an electrically conductive material arranged along a second winding plane, wherein the detection loop (25a,25b) and the corresponding transmitting loop (27a,27b) are arranged contiguous to each other and said first winding plane and second winding plane are parallel, and the first and the second detector units (2a,2b) being arranged with a spacing along a predetermined direction with respect to one another, ▪ at least one excitation coil with a ferrite core adapted to emit an alternating electromagnetic excitation field (Be) of a defined characteristic, which excitation coil is placed inside the housing, arranged with a spacing from the first and second detector units along said predetermined direction, wherein the first detector unit is located between the second detector unit and the excitation coil along the predetermined direction, and arranged in such a way that the sensitivity direction of the detection loops of the first and second detector units(25a,25b) is substantially in line with the field emission direction of the excitation coil, ▪ an electronic signal evaluation unit adapted to detect the utility line according to an electrical signal induced in the detection loops (25a,25b) of the detector units (2a,2b) and to evaluate the depth value according to a difference of the electrical signal in-between the detection loops (25a,25b), and ▪ a compensation unit configured to apply an individual electrical signal to each of the transmitting loops (27a,27b) arranged to establish an individual compensation field (Bta,Btb) by each of the transmitting loops (27a,27b), which individual compensation field (Bta,Btb) is configured to substantially nullify influences of the excitation field (Be) at each of the detection loop (25a,25b); wherein the compensation unit is further configured to simultaneously apply the individual electrical signal to each of the transmitting loops (27a,27b) at both detector units (2a,2b) and to control the applied individual electrical signals in such a way, that a simultaneous nullification at both detector units (2a,2b) is established.