SURVEYING POLE AND SECONDARY SENSOR UNIT HAVING TOROIDAL FORM

The invention relates to a surveying pole (1) and to a secondary sensor unit (2) which is attachable to the surveying pole (1). A reflector (10) and/or GNSS receiver attachable to the surveying pole (1) can be attached independently of whether or not the secondary sensor unit (2) is attached to the surveying pole (1). A distance between the reflector (10) and/or GNSS receiver and a pole tip (12) is also independent of whether or not the secondary sensor unit (2) is attached to the surveying pole (1). A distance between an attached reflector (10) and/or GNSS receiver and the attached secondary sensor unit (2) is also known and fixed. The invention also relates to a method and computer program product for numerically correcting distance measurement errors due to reflector (10) orientation and position with respect to a primary sensor (14), in particular a tachymeter.