2.4.3 Selection of measurements (u)
Controllability considerations, including dynamic behavior, are important when selecting
which variables to measure. There are often many possible measurements we can make,
and the number, location and accuracy of the measurement is a tradeoff between cost of
measurements and benefits of improved control. A controllability analysis may be very
useful. In most cases the selection of measurements must be considered simultaneously
with the selection of the control configuration. For example, this applies to the issue of
stabilization and the use of secondary measurements.