A set comprising a sensor carrier and a needle-like instrument, wherein said sensor carrier comprises an elongate carrier body having proximal and distal ends, and a sensor is attached to or enclosed by said sensor carrier body close to its distal end, wherein said sensor is suitable for carrying out measurements allowing for determining the position of the sensor within an electromagnetic navigation field, wherein said needle-like instrument has - a sterile distal portion and an optionally non-sterile proximal portion, - a removable protection device for encapsulating the sterile portion, and - an adapter at a predetermined connection position located on said optionally non-sterile portion, wherein the adapter of said needle-like element and an adaptor of said sensor carrier together form a connection mechanism, which allows for connecting or mounting the sensor carrier at said predetermined connection position and with a predetermined orientation of said sensor carrier body with respect to said needle-like instrument, such that when said sensor carrier is connected with said needle-like instrument via said connection mechanism, said sensor is automatically located at a predetermined and known position relative to the distal end of said sterile distal portion, wherein said adaptor of said sensor carrier allows to releasably connect said sensor carrier with said optionally non-sterile proximal portion of said needle-like instrument at said connection position and with said predetermined orientation of said elongate sensor carrier body with respect to said needle-like instrument, such that when said sensor carrier is connected with said instrument via its adapter, • said elongate carrier body extends from said connection position in distal direction, and • said sensor is automatically located at said predetermined and known position relative to the distal end of said sterile distal portion. wherein said needle-like instrument has - a sterile distal portion and an optionally non-sterile proximal portion, - a removable protection device for encapsulating the sterile portion, and - an adapter at a predetermined connection position located on said optionally non-sterile portion, wherein the adapter of said needle-like element and an adaptor of said sensor carrier together form a connection mechanism, which allows for connecting or mounting the sensor carrier at said predetermined connection position and with a predetermined orientation of said sensor carrier body with respect to said needle-like instrument, such that when said sensor carrier is connected with said needle-like instrument via said connection mechanism, said sensor is automatically located at a predetermined and known position relative to the distal end of said sterile distal portion, - a sterile distal portion and an optionally non-sterile proximal portion, - a removable protection device for encapsulating the sterile portion, and - an adapter at a predetermined connection position located on said optionally non-sterile portion, wherein the adapter of said needle-like element and an adaptor of said sensor carrier together form a connection mechanism, which allows for connecting or mounting the sensor carrier at said predetermined connection position and with a predetermined orientation of said sensor carrier body with respect to said needle-like instrument, such that when said sensor carrier is connected with said needle-like instrument via said connection mechanism, said sensor is automatically located at a predetermined and known position relative to the distal end of said sterile distal portion, wherein said adaptor of said sensor carrier allows to releasably connect said sensor carrier with said optionally non-sterile proximal portion of said needle-like instrument at said connection position and with said predetermined orientation of said elongate sensor carrier body with respect to said needle-like instrument, such that when said sensor carrier is connected with said instrument via its adapter, • said elongate carrier body extends from said connection position in distal direction, and • said sensor is automatically located at said predetermined and known position relative to the distal end of said sterile distal portion. • said elongate carrier body extends from said connection position in distal direction, and • said sensor is automatically located at said predetermined and known position relative to the distal end of said sterile distal portion.