Monitoring device for monitoring a physiological parameter and methods thereof

A method to process signals acquired with at least one accelerometer and one gyroscope for the evaluation of a heart rate and/or a respiratory rate of a subject wearing said accelerometer and said gyroscope, said method comprising the following steps:

• reception of the signals acquired with a predefined sampling frequency by the accelerometer and the gyroscope in a given time window;
• for each corresponding pair of samples of signals acquired by the accelerometer and the gyroscope in the given time window, combination of the samples of signals of the accelerometer and the gyroscope so as to output an orientation vector for each sampling time;
• application of at least one filter to the orientation signal defined by the orientation vectors obtained for the sampling times in the given time window so as to obtain a filtered signal;
• calculating an average breath cycle and/or an average time interval separating two consecutive heart beats using an algorithm for modeling an average signal configured to iteratively determine the average between the filtered signal obtained for the given time window and the average signal obtained in a preceding iteration for a preceding time window;
• and
• estimation of a heart rate and/or a respiratory rate from the average breath cycle and/or the average time interval separating two consecutive heart beats calculated.