Representative methods, apparatus and systems are disclosed for blood pressure and other vital sign monitoring using arterial applanation tonometry, including ambulatory blood pressure and other vital sign monitoring. A representative system comprises a wearable apparatus. The various embodiments measure blood pressure and other vital sign monitoring using a plurality of pressure sensors of a pressure sensor array, with one or more of the pressure sensors 140 applanating an artery, such as a radial artery. In a first embodiment, a pressure sensor signal is utilized which has the highest cross-coherence with the signals of its nearest pressure sensor neighbors of the pressure sensor array. In a second embodiment, Kalman filtering is utilized for the pressure sensor signals from the pressure sensor array.
