A remote sensing system comprising: an internal antenna unit securable to the lower surface of a cover element, especially a manhole cover, configured to receive a signal from a transmitting unit especially placed within manhole; an external antenna unit for transmitting a signal to a communication device outside of the upper surface of the cover element, especially the manhole cover; the external antenna unit configured to be placed within an aperture, the aperture perforating the cover element, especially the manhole cover, from the upper to the lower surface of the cover element, especially the manhole cover, and the external antenna unit not protruding beyond the upper surface of the cover element, especially the manhole cover; coupling means electrically coupling the internal antenna unit to the external antenna unit, whereby the internal antenna unit and the external antenna unit are coupled by the coupling means for transmitting a signal from the internal antenna unit to the external antenna unit, characterized in that the external antenna unit is flexibly attached to the lower surface of the cover element, especially of the manhole cover, and is not attached to the walls of the aperture, and the remote sensing system further comprises a holding body having a first arm extending into a first direction and a second arm extending in a second direction essentially perpendicular to the first direction, wherein the first arm is flexibly attached to the lower surface of the cover element, especially the manhole cover, by attachment means, and the second arm comprises the external antenna unit and extends into the aperture, wherein the attachment means are made of a polymer having a high flexibility and the second arm is not attached to the walls of the aperture, so that a gap is provided between the second arm and the wall of the aperture. an internal antenna unit securable to the lower surface of a cover element, especially a manhole cover, configured to receive a signal from a transmitting unit especially placed within manhole; an external antenna unit for transmitting a signal to a communication device outside of the upper surface of the cover element, especially the manhole cover; the external antenna unit configured to be placed within an aperture, the aperture perforating the cover element, especially the manhole cover, from the upper to the lower surface of the cover element, especially the manhole cover, and the external antenna unit not protruding beyond the upper surface of the cover element, especially the manhole cover; the external antenna unit configured to be placed within an aperture, the aperture perforating the cover element, especially the manhole cover, from the upper to the lower surface of the cover element, especially the manhole cover, and the external antenna unit not protruding beyond the upper surface of the cover element, especially the manhole cover; coupling means electrically coupling the internal antenna unit to the external antenna unit, whereby the internal antenna unit and the external antenna unit are coupled by the coupling means for transmitting a signal from the internal antenna unit to the external antenna unit, characterized in that the external antenna unit is flexibly attached to the lower surface of the cover element, especially of the manhole cover, and is not attached to the walls of the aperture, and the remote sensing system further comprises a holding body having a first arm extending into a first direction and a second arm extending in a second direction essentially perpendicular to the first direction, wherein the first arm is flexibly attached to the lower surface of the cover element, especially the manhole cover, by attachment means, and the second arm comprises the external antenna unit and extends into the aperture, wherein the attachment means are made of a polymer having a high flexibility and the second arm is not attached to the walls of the aperture, so that a gap is provided between the second arm and the wall of the aperture.