CFAR

The false alarm issue can be resolved by implementing the constant false alarm rate. CFAR varies the detection threshold based on the vehicle surroundings. The CFAR technique estimates the level of interference in radar range and doppler cells “Training Cells” on either or both the side of the “Cell Under Test”. The estimate is then used to decide if the target is in the Cell Under Test (CUT).

The process loops across all the range cells and decides the presence of target based on the noise estimate.The basis of the process is that when noise is present, the cells around the cell of interest will contain a good estimate of the noise, i.e. it assumes that the noise or interference is spatially or temporarily homogeneous. Theoretically it will produce a constant false alarm rate, which is independent of the noise or clutter level

There are multiple categories of CFAR:

• Cell Averaging CFAR (CA-CFAR)
• Ordered Statistics CFAR (OS CFAR)
• Maximum Minimum Statistic (MAMIS CFAR)
• And, multiple variants of CA-CFAR.

Here, we will be covering the basic CA-CFAR.