<title>Doppler estimation using a coherent ultrawideband random noise radar</title>

Abstract

Abstract-The University of Nebraska has developed an ultrawide-band (UWB) coherent random noise radar operating over the 1-2 GHz frequency range. The system achieves phase coherence by using heterodyne correlation of the received signal with a time-delayed frequency-shifted replica of the transmit waveform. Knowledge of the phase of the received signal and its time dependence due to target motion permits the extraction of the mean Doppler frequency from which the target speed can be inferred. Theoretical analysis, simulation studies, and laboratory measurements using a microwave delay line showed that it was possible to estimate the Doppler frequency from targets with linear as well as rotational motion. Field measurements using a photonic delay line demonstrated the success of this technique at a range of about 200 m at target speeds of up to 9 m/s. Analysis shows that the accuracy with which the Doppler frequency can be estimated depends not only on the phase performance of various components within the system, but also upon the random nature and bandwidth (BW) of the transmit waveform, and the characteristics of unsteady target motion.Index Terms-Doppler estimation, random noise radar, ultrawide-band radar.

<title>Simulation of the effect of phase uncertainties on the estimation of linear Doppler velocities using coherent random noise radar</title>

“…The peak phase modulation index of the IF output, 9(r), can be shown to be 2,3 O(r) = 9o2irfr (1) where f is the spurious modulating frequency and r = is a range related delay and 9o is the transmitter modulation index.…”

Periodicity in contrast with sidelobe suppression in random signal radars

“…In pulse and FMCW radars this problem was solved due to time and frequency separation. In Noise radars, randomness of signal makes no such seperation feasible and it leads to reducing radar sensitivity and detection range [3][4][5][6][7][8].…”

<title>Receiver operating characteristics (ROC) for coherent ultrawideband random noise radar</title>

“…Simulation studies and controlled laboratory tests confirm the system's ability to detect a target and also to preserve the instantaneous phase of the received signal despite the fact that the transmitted signal is white Gaussian random noise.1'2 The ability of the system to characterize the Doppler shift of moving targets exhibiting varying linear and rotational velocities was clearly demonstrated. 2 This paper attempts to investigate the performance of this radar from a statistical point of view by developing PDF and CDF of in-phase (I) and quadrature (Q) channels which are then used to obtain receiver operating characteristics (ROC).…”