Phase Noise Mitigation for Multistatic FMCW Radar Sensor Networks Using Carrier Transmission

Abstract

For incoherent radar sensor networks it is desirable to perform both monostatic and bistatic distance measurements. Especially the bistatic measurements enable to achieve additional information about a target. As for bistatic measurements different local oscillators (LO) are used for system operation, the phase noise (PN) at the receiving (RX) sensor node is uncorrelated to the PN of the transmitter (TX). This effect usually degrades the signal-to-noise ratio (SNR) for bistatic measurements in comparison to monostatic measurements. This letter briefly discusses the problem of PN correlation in bistatic distance measurements and proposes a novel system approach that mitigates phase errors between TX and RX oscillators. The proposed concept is mathematically derived and proven with measurements using a radar demonstrator at 77 GHz.

Coherent Automotive Radar Networks: The Next Generation of Radar-Based Imaging and Mapping

“…Using the wireless broadcast of reference chirp signals for downconversion, which is termed over-the-air deramping (OTAD), accurate synchronization and coherence of multistatic systems can be ensured [38]. A related system concept for distributed detection of passive targets and PN reduction directly transmits the RF carrier for down-conversion at a second station [39]. Phase stable frequency synthesis of quasi-coherent distributed radar is enabled by sharing a reference signal with a frequency close to the desired RF over a wired link in addition to the compensation of the phase difference [40].…”

Strategic method of determining parameter values in frequency modulated continuous wave radar for low noise floor over middle‐long range

“…Heterodyne FMCW radar has frequently been employed to resolve the problem of dc offsets 9‐12 . However, as the heterodyne FMCW radar usually uses different local oscillators (LOs), it causes uncorrelated phase noise (UPN) and the RCE has little or no effect, which results in an increase in the noise floor 10 .…”

“…Heterodyne FMCW radar has frequently been employed to resolve the problem of dc offsets 9‐12 . However, as the heterodyne FMCW radar usually uses different local oscillators (LOs), it causes uncorrelated phase noise (UPN) and the RCE has little or no effect, which results in an increase in the noise floor 10 . When the configuration of the radar is monostatic or quasi‐monostatic, the leakage signal, which is a drawback of the FMCW radar, becomes intensely strong and can worsen the noise floor rise 11,12 .…”

Crosstalk in modern software defined radio for the implementation of frequency modulated continuous wave radar

“…FMCW radars are used for a range of diverse applications [3], for example, Moving Target Detection radars, vital sign detection systems, Synthetic Aperture Radars and most recently in the automotive radars, all use FMCW signal transmission [4]. FMCW radars use linear frequency modulation (LFM) and its transmitted signal s ( t ) is given as for 0 < t < T , where A and f tx are the amplitudes and start frequency of the reference LFM signal, B and T are sweep bandwidth and sweep period respectively [5–7]. The crosstalk is a phenomenon by which a signal transmitted from one circuit causes disturbance in the other circuit hence affecting the performance of the other circuit [8].…”

“…for 0 < t < T, where A and f tx are the amplitudes and start frequency of the reference LFM signal, B and T are sweep bandwidth and sweep period respectively [5][6][7]. The crosstalk is a phenomenon by which a signal transmitted from one circuit causes disturbance in the other circuit hence affecting the performance of the other circuit [8].…”