Sensor assembly for detecting position of target surface based on a reference portion of target surface and method

Sensor body 32 extends through first structure 16, and second structure 18 (Fig. 1) disposed radially outwardly of first structure 16. Structures 16 and 18 may be casings of an aircraft turbine engine. First end 34 of sensor body 32 is disposed proximate first environment 14; second end 36 is located radially outwardly of second structure 18. Sealing assembly 50 couples sensor body 32 to second structure 18, and accommodates movement of sensor body 32. Position sensor 42 is coupled to sensor body 32 and determines a position of a target 13. Target 13 may be an adjustable stator vane; its position may be an angular displacement. Target surface 104 has reference portion 106 and adjacent inclined portion 108. Position sensor 42 detects the position of target 13 based on a differential between a distance from sensor 42 to reference portion 106 and a distance from sensor 42 to inclined portion 108, advantageously accounting for thermal effects.