Recommended mcu for 2-state kalman filter

[johangustafsson]

Hi,

I would like to design a circuit board using an accelerometer to monitor high frequent and high accelerations (a blasting sensor, construction machine sensor). The sensor will monitor all 3 directions, but will filter these independent as the sensor is not supposed to rotate (less than 1 degree movement). It will be equipped with a 3-directional mems-sensor and 3 independent geophones that measures velocity.

The filter

I will sample the mems-sensor and the geophones at 2-4 kS/s (probably 4 kS/s), and perform a simple kalman filter. It'll only look in one direction per filter, thus have only 2 states = acceleration and velocity, and 2 measurement corrections.

This filter will be tripled for each direction.

Times and updates

The output from the filter will be sent over GSM/Radio to a base station/server. This can be performed at times when there is movement below a certain threshold on the sensors, thus no need for the filter to run.

MCU

What MCU do you recomend for this filter? Would having 3 x 2state filter running at 4 KHz be any problems for the sensors boards?

Kind regards,

Johan

[shubhadippaul-b]

Hi Johan,

For digital sensors there is no significant benefit running the filter at rates higher that the actual Sensor Data Rate.

As such you may want to run your algorithm close to Sensor ODR.

Reading the Sensor Data at rates significantly higher than the Sensors MAX supported rate my introduce noise but other than that should not be a problem for the Sensor or the Sensor Board. However, at the MCU side you are adding up transactions which would simply return the same data when reading faster than the sensors ODR.

For a system to support a Fusion Algorithm and a Communication Protocol, an ARM M4 core based MCU should suffice. You may want to consider the Kinetis FRDM-K22F MCU board as an option.