9.7 Sensor Fusion(Complementary Filtering) 33/35 Sensor Fusion:combine several sensors into a measurement system that utilizes the best qualities of each individual device to meet all the required performance specifications for a particular variable measurement. If the sensors complement each other,giving rise to the name complementary filtering. Complementary filtering aiding sensor fusion. Direct fusion is the fusion of sensor data from a set of sensors,soft sensors, and history values of sensor data; Indirect fusion uses information sources like a priori knowledge about the environment and human input. -Fusion of the output of direct indirect fusions. A more advanced version of a similar idea is called Kalman filtering. -Kalman filter,also known as linear quadratic estimation (LQE),is an algorithm which uses a series of measurements observed over time, containing noise and other inaccuracies,and produces estimates of unknown variables that tend to be more precise than those that would be based on a single measurement alone. 34/35 9.7 Sensor Fusion (Complementary Filtering) BAROMETRIC PRESSURE NOISE BAROMETRIC ALTITUDE hb 啊 0.0025s2+0.05s+ 1 compfih2.m Band-Limited s+1 White Noise 1 NOISE POWER =5.0 noise LO-PASS FILTER MEASURED ALTITUDE SAMPLE TIME =0.1 SEC hm SEED=23341 四 h Sum1 TRUE ALTITUDE THE BAROMETRIC PRESSURE NOISE IS GENERATED BY LOW-PASS FILTERING THE BAND-LIMITED WHITE NOISE s+l HI-PASS FILTER ha Clockl INERTIAL (ACCELEROMETER-BASED)ALTITUDE 80 ACCELEROMETER BIAS ERROR Figure 9.21 Sensor Fusion of Barometric Inertial Altitude Signals (The baroinertial altimeter is used in many practical flight vehicles.)z Sensor Fusion: combine several sensors into a measurement system that utilizes the best qualities of each individual device to meet all the required performance specifications for a particular variable measurement. z If the sensors complement each other, giving rise to the name complementary filtering. z Complementary filtering = aiding = sensor fusion. - Direct fusion is the fusion of sensor data from a set of sensors, soft sensors, and history values of sensor data; - Indirect fusion uses information sources like a priori knowledge about the environment and human input. - Fusion of the output of direct & indirect fusions. z A more advanced version of a similar idea is called Kalman filtering. - Kalman filter, also known as linear quadratic estimation (LQE), is an algorithm which uses a series of measurements observed over time, containing noise and other inaccuracies, and produces estimates of unknown variables that tend to be more precise than those that would be based on a single measurement alone. 9.7 Sensor Fusion (Complementary Filtering)33/35 9.7 Sensor Fusion (Complementary Filtering) Figure 9.21 Sensor Fusion of Barometric Inertial Altitude Signals (The baroinertial altimeter is used in many practical flight vehicles.) 34/35