Professional Android Sensor Programming

Chapter 6

Errors and Sensor Signal Processing

What's in this chapter?

Outlining the errors that occur in sensor data

Explaining algorithms for filtering data

Understanding sensor fusion schemes

Sensors do not measure values perfectly. Instead, they can often produce data that is incorrect due to noise or because of degradation that occurs over time. Both of these problems may introduce errors in the resulting data.

Fortunately, algorithms and techniques exist to address these errors. To reduce errors, an app can filter output from individual sensor readings or fuse results from multiple sensors. Additionally, some of Android's synthetic sensors execute filtering algorithms or perform the sensor fusion for you.

This chapter first explores what kinds of errors can occur. Then, it describes filtering techniques that can help remove errors from individual sensor readings. Finally, it describes some sensor fusion schemes to combine outputs of multiple sensors to create improved results.

If Android does not provide a synthetic sensor you need, this chapter gives you the understanding you need to develop an approach and improve the quality of sensor data output. If Android does provide a synthetic sensor you need, this chapter helps you understand how such sensors work.

Definitions

Before describing filtering algorithms or sensor fusion schemes, it is useful to understand different terminology to describe errors, what types of errors can occur, and what kinds of techniques exist to address ...