  Orthogonal time frequency space (OTFS) modulation has recently been
identified as a suitable waveform for joint radar and communication systems.
Focusing on the effect of data modulation on the radar sensing performance, we
derive the ambiguity function (AF) of the OTFS waveform and characterize the
radar global accuracy. We evaluate the behavior of the AF with respect to the
distribution of the modulated data and derive an accurate approximation for the
mean and variance of the AF, thus, approximating its distribution by a Rice
distribution. Finally, we evaluate the global radar performance of the OTFS
waveform with the OFDM waveform.
