Detection System for an evaluation of utility line identification information and location information (13,13a,13b,13c) of one or more occluded utility lines emanating an alternating magnetic field (Bb,Bt), the detection system comprising a mobile detection device and a server, wherein ▪ the mobile detection device is comprising ▪ at least two magnetic detector units (2t,2b) arranged in a defined spacing with respect to each other, which are comprising detection coils for providing an electrical detection signal according to the alternating magnetic field (Bb,Bt), ▪ a spectral analyzing unit built to derive a spectral frequency distribution profile of the electrical detection signal from at least one of the detector units (2t,2b), ▪ a communication interface configured to transmit the spectral frequency distribution profile by a data link to the server, ▪ the server is comprising ▪ a database for frequency distribution profiles of a plurality of known utility lines and ▪ a matching unit configured to derive a utility line identification information of a type or class of one or more utility lines by comparing the spectral frequency distribution profile to frequency distribution profiles of the database and ▪ the mobile detection device ▪ is configured to receive the utility line identification information from the server, ▪ is comprising an electronic signal evaluation unit built for deriving the location information (13a,13b,13c) according to a difference in the electrical signals from the at least two magnetic detector units (2t,2b), and ▪ is comprising a visualisation unit built for charting the one or more utility lines with the utility line location information (13a,13b,13c) and providing the utility line identification information. ▪ the mobile detection device is comprising ▪ at least two magnetic detector units (2t,2b) arranged in a defined spacing with respect to each other, which are comprising detection coils for providing an electrical detection signal according to the alternating magnetic field (Bb,Bt), ▪ a spectral analyzing unit built to derive a spectral frequency distribution profile of the electrical detection signal from at least one of the detector units (2t,2b), ▪ a communication interface configured to transmit the spectral frequency distribution profile by a data link to the server, ▪ at least two magnetic detector units (2t,2b) arranged in a defined spacing with respect to each other, which are comprising detection coils for providing an electrical detection signal according to the alternating magnetic field (Bb,Bt), ▪ a spectral analyzing unit built to derive a spectral frequency distribution profile of the electrical detection signal from at least one of the detector units (2t,2b), ▪ a communication interface configured to transmit the spectral frequency distribution profile by a data link to the server, ▪ the server is comprising ▪ a database for frequency distribution profiles of a plurality of known utility lines and ▪ a matching unit configured to derive a utility line identification information of a type or class of one or more utility lines by comparing the spectral frequency distribution profile to frequency distribution profiles of the database and ▪ a database for frequency distribution profiles of a plurality of known utility lines and ▪ a matching unit configured to derive a utility line identification information of a type or class of one or more utility lines by comparing the spectral frequency distribution profile to frequency distribution profiles of the database ▪ the mobile detection device ▪ is configured to receive the utility line identification information from the server, ▪ is comprising an electronic signal evaluation unit built for deriving the location information (13a,13b,13c) according to a difference in the electrical signals from the at least two magnetic detector units (2t,2b), and ▪ is comprising a visualisation unit built for charting the one or more utility lines with the utility line location information (13a,13b,13c) and providing the utility line identification information. ▪ is configured to receive the utility line identification information from the server, ▪ is comprising an electronic signal evaluation unit built for deriving the location information (13a,13b,13c) according to a difference in the electrical signals from the at least two magnetic detector units (2t,2b), and ▪ is comprising a visualisation unit built for charting the one or more utility lines with the utility line location