The information below describes how the “CFAR point cloud” output from a radar is derived from the radar’s view of the environment surrounding it.
This mode is just one approach to extracting features from the scene that the radar presents.
The key parameters to configure the operation of this feature extraction process can be configured in a radar by Colossus message type 205 and the navigation mode output from the radar can be requested by Colossus message type 120. When this feature extraction method is appropriate, the network bandwidth utilisation for the radar’s connection is greatly reduced.Alternatively, the source code for navigation mode feature extraction function is provided for both C++ and Pythonenvironments. This approach can be used to process the raw radar data within a customer’s complete control, and dynamic adjustment/adaptation of the key parameters is possible.
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International Research Journal of Engineering and Technology (IRJET) Volume: 05 Issue: 07 describes Constant False Alarm Rate (CFAR) Detection as
… an adaptive algorithm used in Radar systems to detect the target echoes against a background of noise and clutter. The role of the constant false alarm rate circuit is to determine the threshold above which any returning signal or echo can be considered probably to be originated from a target. In most radar systems, the threshold is set to achieve a required false alarm rate (or equivalently, probability of false alarm). Cell-Averaging CFAR (CA - CFAR) is a type of CFAR detection where the threshold is estimated by scanning a block of cells around a cell-under-test (CUT) and calculating the average power level. In CA – CFAR, a target is declared to be present if the power level in the CUT exceeds the average power level found from adjacent block of cells. This paper shows the principle of CA – CFAR detector, threshold factors for CFAR detection, factors affecting CFAR detection and CFAR loss
The subsequent text of that article expands on the technicalities around Cell-Averaging-CFAR. In simplistic terms, a sliding window is used to consider a single azimuth of radar data
Radar firmware versions 3.1.0.319 and later support the generation of a Cell-Averaged-CFAR “pointcloud” data output format via a UDP stream https://navtechradar.atlassian.net/wiki/spaces/PROD/pages/2229239935/UDP+Networking#Point-Cloud-Data
A radar must be configured via its' web interface to output data in this mode https://navtechradar.atlassian.net/wiki/spaces/PROD/pages/2265514016/User+-+System+Configuration#Changing-the-Navigation-Data.
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