Fig. 1. (a) Schematic diagram of the proposed radar. MLL, mode-locked laser; DP-DMZM, dual-polarization dual-drive Mach–Zehnder modulator; PBS, polarization beam splitter; PD, photodetector; ADC, analog-to-digital converter; DSP, digital signal processing; LNA, low-noise amplifier; BPF, bandpass filter; TA, transmit antenna; RA, receive antenna. (b) DSP procedures. FFT, fast Fourier transform; CS, compressed sensing.

Fig. 2. (a) Frequency grid formed by N uniformly spaced frequencies. (b) Signal with M pseudo-randomly selected frequencies.

Fig. 3. Frequency profiles of the frequency-hopping sequences. (a) SFHS. (b) PRFHS.

Fig. 4. (a) Target responses obtained by SFHP. (b) Target responses obtained by PRFHP. (c) Target scene for range profile measurement. (d) Range profiles obtained by SFHP and PRFHP.

Fig. 5. (a) Target scene for position estimation. (b) Range profiles obtained by SFHP and PRFHP. Position estimation results obtained by SFHP (c) and PRFHP (d), respectively.