Sensor Fusion or Sensor Confusion?

If you cannot find the sensor you need in any manufacturer s catalogue then you can probably make your own in software.

This is the basic premise behind sensor fusion. The idea is that if you combine the data from a variety of different sensors, you will be able to measure parameters for which no single sensor exists.

An easy example is the electronic nose . These typically comprise an array of 20 or more chemical sensors, each with its own sensitivity to a particular gas or combination of gases. Each sensor is pretty crude and lacks selectivity, however it only needs to have a repeatable set of characteristics for it to be a useful addition to the nose.

It is the combination of various characteristics that enables the nose to discriminate between aromas. And as I cannot believe that evolution provided us with a specific sensor for Chateau Lafitte 1992, I can only presume that our own noses operate in much the same way.

Another even simpler example is the determination of acceleration from a distance sensor and an accurate time signal. This is very easy and straightforward because all the data are instantaneously available and it all relates to the same instant in time.

Difficulties arise if one sensor has a delayed response compared with those of the rest of the system; and these difficulties...