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- Sensor_array abstract "A sensor array is a group of sensors deployed in a certain geometry pattern. The advantage of using a sensor array over using a single sensor lies in the factor that an array can increase the antenna gain in the direction of the signal while decreasing the gain in the directions of noise and interferences. In other words, sensor arrays can increase signal-to-noise ratio (SNR): magnify the signal while suppressing the noise. Another ability of sensor array is that is can detect the direction and distance of impinging signal sources. The technology to achieve this is called Array Signal Processing. Application examples of array signal processing include RADAR/SONAR, wireless communications, seismology, machine condition monitoring and fault diagnosis, etc.Using array signal processing, the temporal and spatial properties (or parameters) of the impinging signals contaminated with noise and hidden in the data collected by the sensor array can be estimated and revealed. This is known as parameter estimation.Figure 1 illustrates a six-element uniform linear array. In this example, the impinging signal is assumed far-field so that it can be treated as planar wave.Parameter estimation takes advantage of the fact that the distance from the source to each microphone in the array is different, which means that the signal recorded by each microphone will be phase-shifted replicas of each other. Eq. (1) shows the calculation for the extra time it takes to reach each microphone in the array relative to the array center, where c is the sound speed.Each sensor is associated with a different delay. Although the delays are small but not trivial. In frequency domain, the delays display as phase shift among the signals received by the sensors. The delays are closely related to the incident angle and the geometry of the sensor array. Given the geometry of the array, the delays or phase differences can be used to estimate the incident angle. This the mathematical basis behind the array signal processing. Simply summing the signals received by the sensors and calculating the mean value give the following result: Because the received signals are out of phase, this mean value does not give an enhanced signal compared with the original source. Heuristically, if we can find weights multiplying to the received signals to make them in phase before summing them together, the mean value will give an enhanced signal:The process of multiplying a well selected set of weights to the signals received by the sensor array so that the signal is added constructively while suppressing the noise is called beamforming. There are a variety of beamforming algorithms for sensor arrays, such as The delay-and-sum approach, spectral based (non-parametric) approaches and parametric approaches. These beamforming algorithms are briefly described as follows.".
- Sensor_array thumbnail Illustration_linear_sensor_array_and_incident_angle.jpg?width=300.
- Sensor_array wikiPageExternalLink SAS-new.pdf.
- Sensor_array wikiPageID "912925".
- Sensor_array wikiPageRevisionID "606264028".
- Sensor_array hasPhotoCollection Sensor_array.
- Sensor_array technical "March 2012".
- Sensor_array unreferenced "December 2009".
- Sensor_array subject Category:Sensors.
- Sensor_array type Artifact100021939.
- Sensor_array type Detector103180969.
- Sensor_array type Device103183080.
- Sensor_array type Instrumentality103575240.
- Sensor_array type Object100002684.
- Sensor_array type PhysicalEntity100001930.
- Sensor_array type Sensors.
- Sensor_array type Whole100003553.
- Sensor_array comment "A sensor array is a group of sensors deployed in a certain geometry pattern. The advantage of using a sensor array over using a single sensor lies in the factor that an array can increase the antenna gain in the direction of the signal while decreasing the gain in the directions of noise and interferences. In other words, sensor arrays can increase signal-to-noise ratio (SNR): magnify the signal while suppressing the noise.".
- Sensor_array label "Sensor array".
- Sensor_array sameAs m.03p8_k.
- Sensor_array sameAs Q7451086.
- Sensor_array sameAs Q7451086.
- Sensor_array sameAs Sensor_array.
- Sensor_array wasDerivedFrom Sensor_array?oldid=606264028.
- Sensor_array depiction Illustration_linear_sensor_array_and_incident_angle.jpg.
- Sensor_array isPrimaryTopicOf Sensor_array.
