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However, in most fielded systems, unwanted clutter and interference sources mean that the noise level changes both spatially and temporally. In this case, a changing threshold can be used, where the threshold level is raised and lowered to maintain a constant probability of false alarm. This is known as constant false alarm rate (CFAR) detection.
Side-lobes are produced during signal processing and a side-lobe suppression strategy, such as Dolph–Chebyshev window function, is required to reduce false alarms . [1] All of the samples taken from the Sample 1 sample period form the input to the first set of filters. This is the first ambiguous range interval.
In pulsed radar and sonar signal processing, an ambiguity function is a two-dimensional function of propagation delay and Doppler frequency, (,).It represents the distortion of a returned pulse due to the receiver matched filter [1] (commonly, but not exclusively, used in pulse compression radar) of the return from a moving target.
Non-Doppler radar systems cannot be pointed directly at the ground due to excessive false alarms, which overwhelm computers and operators. Sensitivity must be reduced near clutter to avoid overload. This vulnerability begins in the low-elevation region several beam widths above the horizon, and extends downward.
The MHT calculates not only the probabilities of previously-detected tracks, but also the probabilities of false alarms and new tracks. As a result, it might handle multiple parts of the radar tracker algorithm, i.e. the plot-to-track, the smoothing, and the initialization. MHT can be implemented as either hypothesis-oriented or track-oriented.
Radar pulsing causes a phenomenon called aliasing, which occurs when the Doppler frequency created by reflector motion exceeds the pulse repetition frequency (PRF). [1] This concept is related to range ambiguity resolution. Doppler frequency shift is introduced onto reflected signals used by radar.
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Range aliasing occurs when reflections arrive from distances that exceed the distance between transmit pulses at a specific pulse repetition frequency (PRF).. Range ambiguity resolution is required to obtain the true range when the measurements are made using a system where the following inequality is true.