Inertial-navigation system uses silicon sensors

摘要

ASTRAP-DOWN inertial-navigation system uses silicon sensors to measure displacement without entailing the bulk and expense of moving parts or GPS receivers. For example, a three-axis accelerometer and three angular-rate sensors can determine the position and velocity of a vehicle such as a robot or radio-controlled aircraft. This hardware configuration requires that you read and integrate the sensor outputs and then combine and process them to obtain stabilized location values. Figure 1 shows one such complete system. An inexpensive 8-bit microcontroller can handle the sensor reading and integration tasks, and perform simple lowpass filtering of the accelerometer's output to remove conversion noise. The microcontroller can even run a basic position and velocity algorithm; alternatively, you can pass the preprocessed data to a DSP system. The NEC (www.necelam.com) μPD78-F9418A microcontroller has seven ADC inputs, so it can handle the six inputs from the sensors.