Author Affiliations
1 State Key Laboratory of Laser Interaction with Mater, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, Jilin 130033, China2 University of Chinese Academy of Sciences, Beijing 100049, Chinashow less
Fig. 1. Schematic of the heterodyne detection system
Fig. 2. Schematic of the I&Q detector
Fig. 3. Processing flow chart of the matched filtering algorithm
Fig. 4. Waveform distortion induced by the matched filtering process. (a) Envelope of the OPM signal; (b) envelope of self-convolution of the OPM signal
Fig. 5. Matched filtering process of medium-range missile. (a) REC signal; (b) power spectrum density of REC signal; (c) OPM signal and REC signal; (d) matched filtered output signal with carrier frequency; (e) envelope of the matched filtered output signal; (f) power spectrum density of the matched filtered output signal
Fig. 6. Matched filtering process of ISS. (a) REC signal; (b) power spectrum density of REC signal; (c) OPM signal and REC signal; (d) matched filtered output signal with carrier frequency; (e) envelope of the matched filtered output signal; (f) power spectrum density of the matched filtered output signal
Fig. 7. Monte Carlo simulation. (a) Range error of medium-range missile; (b) range rate error of medium-range missile; (c) range error of ISS; (d) range rate error of ISS
Fig. 8. CNR versus target range
Fig. 9. CNR versus radar cross section of target
Fig. 10. Power spectral density of echo signal with different sampling rates. (a) 100 MHz; (b) 400 MHz; (c) 700 MHz; (d) 1 GHz; (e) 10 GHz; (f) 20 GHz
Fig. 11. Envelope of the matched-filtered signal with different sampling rates. (a) 100 MHz; (b) 400 MHz; (c) 700 MHz; (d) 1 GHz; (e) 10 GHz; (f) 20 GHz
Item | Parameter | Value |
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| Energy /pulse | 10 J@10R(18)-13CO2 | | Pulse recurrence frequency | 10 Hz | | Pulse width | 2.5 μs | | Wavelength λ | 11.15 μm | | Aperture diameter | 60 cm | Transmitter | Optical transmission | 55% | | Heterodyne efficiency | 60% | | Quantum efficiency | 35% | | Frequency fidelity | Single transverse and longitudinal mode | | Resonator | Unstable, 4 cm×4 cm, M=1.25, L=2.5 m | | LO power | ~0.5 mW @shot noise limited operation | | Detector | HgCdTe (77 K) | Receiver | Bandwidth | >100 MHz | | Pre-amplifier gain | >40 dB |
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Table 1. Heterodyne detection system parameters
Parameter | Value |
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Energy /pulse Et | 10 J@10R(20)-13CO2 | Atmosphere transmission T | 0.8 | Transmission system efficiency Kt | 0.75 | Receiving system efficiency Kr | 0.7 | Aperture D | 0.6 m | Target reflectivity ρ | 0.2 | Target Area δ | 10-100 m2 | Pulse duration Δt | 2.5 μs | Target range R | 10-1000 km | Divergence angle θt | 0.1 mrad |
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Table 2. Heterodyne detection system parameters
Target | Target area δ /m2 | Target range R /km | Velocity /Ma |
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Medium-range missile | 5 | 10-300 | 10 | ISS | 100 | 380-1500 | 22-23 |
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Table 3. Parameters of two types of target