Abstract

A coherent three-dimensional (angle–angle–range) lidar imager using a master-oscillator-power-amplifier concept and operating at a wavelength of 1.5 μm with chirp-pulse compression is described. A fiber-optic delay line in the local oscillator path enables a single continuous-wave semiconductor laser source with a modulated drive waveform to generate both the constant-frequency local oscillator and the frequency chirp. A portion of this chirp is gated out and amplified by a two-stage fiber amplifier. The digitized return signal was compressed by cross correlating it with a sample of the outgoing pulse. In this way a 350-ns, 10-μJ pulse with a 250-MHz frequency sweep is compressed to a width of approximately 8 ns. With a 25-mm output aperture, the lidar has been used to produce three-dimensional images of hard targets out to a range of approximately 2 km with near-diffraction-limited angular resolution and submeter range resolution.

© 2005 Optical Society of America

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References

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  1. J. Massa, G. Buller, A. Walker, G. Smith, S. Cova, M. Umasuthan, A. Wallace, “Optical design and evaluation of a three-dimensional imaging and ranging system based on time-correlated single-photon counting,” Appl. Opt. 41, 1063–1070 (2002).
    [CrossRef] [PubMed]
  2. S. M. Hannon, J. A. Thomson, S. W. Henderson, P. Gatt, R. Stoneman, D. Bruns, “Agile multiple pulse coherent lidar for range and micro-Doppler measurement,” in Laser Radar Technology and Applications III, G. W. Kamerman, ed., Proc. SPIE3380, 259–264 (1998).
    [CrossRef]
  3. M. A. Albota, R. M. Heinrichs, D. G. Kocher, D. G. Fouche, B. E. Player, M. E. OBrien, B. F. Aull, J. J. Zayhowski, J. Mooney, B. C. Willard, R. R. Carlson, “Three-dimensional imaging laser radar with a photon-counting avalanche photodiode array and microchip laser,” Appl. Opt. 41, 7671–7678 (2002).
    [CrossRef]
  4. K. F. Hulme, B. S. Collins, G. D. Constant, J. T. Pinson, “A CO2 laser rangefinder using heterodyne detection and chirp pulse compression,” Opt. Quantum Electron. 13, 35–45 (1981).
    [CrossRef]
  5. M. J. Halmos, D. M. Henderson, R. L. Duvall, “Pulse compression of an FM chirped CO2 laser,” Appl. Opt. 28, 3595–3602 (1989).
    [CrossRef] [PubMed]
  6. M. W. Phillips, S. M. Hannon, P. G. Wanninger, P. J. M. Suni, A. L. Thomson, R. D. Richmond, “Range Doppler imaging with a coherent laser radar based upon optical fiber amplifiers,” in Coherent Laser Radar: Technology and Application, Vol. 191995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), paper ThA2, pp. 250–253.
  7. C. J. Karlsson, F. A. Olsson, “Linearization of the frequency sweep of a frequency-modulated continuous-wave semiconductor laser radar and the resulting ranging performance,” Appl. Opt. 38, 3376–3386 (1999).
    [CrossRef]
  8. A. H. Reynolds, “CO2 ladar modulation trade-off studies,” in Coherent Infrared Radar Systems and Applications II, R. C. Harney, ed., Proc. SPIE415, 155–165 (1983).
    [CrossRef]
  9. R. D. Peterson, K. L. Schepler, “Timing modulation of a 40-MHz laser-pulse train for target ranging and identification,” Appl. Opt. 42, 7191–7196 (2003).
    [CrossRef]
  10. J. Overbeck, M. S. Salisbury, M. B. Mark, E. A. Watson, “Required energy for a laser radar system incorporating a fiber amplifier or an avalanche photodiode,” Appl. Opt. 34, 7724–7730 (1995).
    [CrossRef] [PubMed]
  11. O. Steinvall, “Effects of target shape and reflection on laser radar cross sections,” Appl. Opt. 39, 4381–4391 (2000).
    [CrossRef]
  12. A. V. Jelalian, Laser Radar (Artech House, Boston, Mass., 1991).
  13. M. L. Simpson, C. A. Bennett, M. S. Emery, D. P. Hutchinson, G. H. Miller, R. K. Richards, D. N. Sitter, “Coherent imaging with two-dimensional focal-plane arrays: design and applications,” Appl. Opt. 36, 6913–6920 (1997).
    [CrossRef]
  14. J. H. Shapiro, B. A. Capron, R. C. Harney, “Imaging and target detection with a heterodyne-reception optical radar,” Appl. Opt. 20, 3292–3313 (1981).
    [CrossRef] [PubMed]
  15. H. Ahlberg, S. Lundqvist, D. Letalick, I. Renhorn, O. Steinvall, “Imaging Q-switched CO2 laser radar with heterodyne detection: design and evaluation,” Appl. Opt. 25, 2891–2897 (1986).
    [CrossRef]
  16. C. J. Karlsson, F. A. Olsson, D. Letalick, M. Harris, “All-fiber multifunction continuous-wave coherent laser radar at 1.55 μm for range, speed, vibration, and wind measurements,” Appl. Opt. 39, 3716–3726 (2000).
    [CrossRef]
  17. D. Taverner, D. J. Richardson, L. Dong, J. E. Caplen, K. Williams, R. V. Plenty, “158-μJ pulses from a single-transverse-mode large-mode-area erbium-doped fiber amplifier,” Opt. Lett. 22, 378–380 (1997).
    [CrossRef] [PubMed]
  18. G. Kulcsar, Y. Jaouen, G. Canat, E. Olmedo, G. Debarge, “Multiple-Stokes stimulated Brillouin scattering generation in pulsed high-power double-cladding Er3+Yb3+ codoped fibre amplifier,” IEEE Photon. Technol. Lett. 15, 801–803 (2003).
    [CrossRef]
  19. A. W. Rihaczek, Principles of High-Resolution Radar (Artech House, Norwood, Mass., 1996).
  20. M. Harris, G. N. Pearson, K. D. Ridley, C. J. Karlsson, F. A. Olsson, D. Letalick, “Single-particle laser Doppler anemometry at 1.55 μm,” Appl. Opt. 40, 969–973 (2001).
    [CrossRef]
  21. G. N. Pearson, P. J. Roberts, J. R. Eacock, M. Harris, “Analysis of the performance of a coherent pulsed fiber lidar for aerosol backscatter applications,” Appl. Opt. 41, 6442–6450 (2002).
    [CrossRef] [PubMed]
  22. R. G. Frehlich, M. J. Kavaya, “Coherent laser radar performance for general atmospheric refractive turbulence,” Appl. Opt. 30, 5325–5352 (1991).
    [CrossRef] [PubMed]
  23. P. F. Panter, Modulation, Noise, and Spectral Analysis, (McGraw-Hill, New York, 1965), Sect. 5.9.

2003 (2)

R. D. Peterson, K. L. Schepler, “Timing modulation of a 40-MHz laser-pulse train for target ranging and identification,” Appl. Opt. 42, 7191–7196 (2003).
[CrossRef]

G. Kulcsar, Y. Jaouen, G. Canat, E. Olmedo, G. Debarge, “Multiple-Stokes stimulated Brillouin scattering generation in pulsed high-power double-cladding Er3+Yb3+ codoped fibre amplifier,” IEEE Photon. Technol. Lett. 15, 801–803 (2003).
[CrossRef]

2002 (3)

2001 (1)

2000 (2)

1999 (1)

1997 (2)

1995 (1)

1991 (1)

1989 (1)

1986 (1)

1981 (2)

K. F. Hulme, B. S. Collins, G. D. Constant, J. T. Pinson, “A CO2 laser rangefinder using heterodyne detection and chirp pulse compression,” Opt. Quantum Electron. 13, 35–45 (1981).
[CrossRef]

J. H. Shapiro, B. A. Capron, R. C. Harney, “Imaging and target detection with a heterodyne-reception optical radar,” Appl. Opt. 20, 3292–3313 (1981).
[CrossRef] [PubMed]

Ahlberg, H.

Albota, M. A.

Aull, B. F.

Bennett, C. A.

Bruns, D.

S. M. Hannon, J. A. Thomson, S. W. Henderson, P. Gatt, R. Stoneman, D. Bruns, “Agile multiple pulse coherent lidar for range and micro-Doppler measurement,” in Laser Radar Technology and Applications III, G. W. Kamerman, ed., Proc. SPIE3380, 259–264 (1998).
[CrossRef]

Buller, G.

Canat, G.

G. Kulcsar, Y. Jaouen, G. Canat, E. Olmedo, G. Debarge, “Multiple-Stokes stimulated Brillouin scattering generation in pulsed high-power double-cladding Er3+Yb3+ codoped fibre amplifier,” IEEE Photon. Technol. Lett. 15, 801–803 (2003).
[CrossRef]

Caplen, J. E.

Capron, B. A.

Carlson, R. R.

Collins, B. S.

K. F. Hulme, B. S. Collins, G. D. Constant, J. T. Pinson, “A CO2 laser rangefinder using heterodyne detection and chirp pulse compression,” Opt. Quantum Electron. 13, 35–45 (1981).
[CrossRef]

Constant, G. D.

K. F. Hulme, B. S. Collins, G. D. Constant, J. T. Pinson, “A CO2 laser rangefinder using heterodyne detection and chirp pulse compression,” Opt. Quantum Electron. 13, 35–45 (1981).
[CrossRef]

Cova, S.

Debarge, G.

G. Kulcsar, Y. Jaouen, G. Canat, E. Olmedo, G. Debarge, “Multiple-Stokes stimulated Brillouin scattering generation in pulsed high-power double-cladding Er3+Yb3+ codoped fibre amplifier,” IEEE Photon. Technol. Lett. 15, 801–803 (2003).
[CrossRef]

Dong, L.

Duvall, R. L.

Eacock, J. R.

Emery, M. S.

Fouche, D. G.

Frehlich, R. G.

Gatt, P.

S. M. Hannon, J. A. Thomson, S. W. Henderson, P. Gatt, R. Stoneman, D. Bruns, “Agile multiple pulse coherent lidar for range and micro-Doppler measurement,” in Laser Radar Technology and Applications III, G. W. Kamerman, ed., Proc. SPIE3380, 259–264 (1998).
[CrossRef]

Halmos, M. J.

Hannon, S. M.

M. W. Phillips, S. M. Hannon, P. G. Wanninger, P. J. M. Suni, A. L. Thomson, R. D. Richmond, “Range Doppler imaging with a coherent laser radar based upon optical fiber amplifiers,” in Coherent Laser Radar: Technology and Application, Vol. 191995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), paper ThA2, pp. 250–253.

S. M. Hannon, J. A. Thomson, S. W. Henderson, P. Gatt, R. Stoneman, D. Bruns, “Agile multiple pulse coherent lidar for range and micro-Doppler measurement,” in Laser Radar Technology and Applications III, G. W. Kamerman, ed., Proc. SPIE3380, 259–264 (1998).
[CrossRef]

Harney, R. C.

Harris, M.

Heinrichs, R. M.

Henderson, D. M.

Henderson, S. W.

S. M. Hannon, J. A. Thomson, S. W. Henderson, P. Gatt, R. Stoneman, D. Bruns, “Agile multiple pulse coherent lidar for range and micro-Doppler measurement,” in Laser Radar Technology and Applications III, G. W. Kamerman, ed., Proc. SPIE3380, 259–264 (1998).
[CrossRef]

Hulme, K. F.

K. F. Hulme, B. S. Collins, G. D. Constant, J. T. Pinson, “A CO2 laser rangefinder using heterodyne detection and chirp pulse compression,” Opt. Quantum Electron. 13, 35–45 (1981).
[CrossRef]

Hutchinson, D. P.

Jaouen, Y.

G. Kulcsar, Y. Jaouen, G. Canat, E. Olmedo, G. Debarge, “Multiple-Stokes stimulated Brillouin scattering generation in pulsed high-power double-cladding Er3+Yb3+ codoped fibre amplifier,” IEEE Photon. Technol. Lett. 15, 801–803 (2003).
[CrossRef]

Jelalian, A. V.

A. V. Jelalian, Laser Radar (Artech House, Boston, Mass., 1991).

Karlsson, C. J.

Kavaya, M. J.

Kocher, D. G.

Kulcsar, G.

G. Kulcsar, Y. Jaouen, G. Canat, E. Olmedo, G. Debarge, “Multiple-Stokes stimulated Brillouin scattering generation in pulsed high-power double-cladding Er3+Yb3+ codoped fibre amplifier,” IEEE Photon. Technol. Lett. 15, 801–803 (2003).
[CrossRef]

Letalick, D.

Lundqvist, S.

Mark, M. B.

Massa, J.

Miller, G. H.

Mooney, J.

OBrien, M. E.

Olmedo, E.

G. Kulcsar, Y. Jaouen, G. Canat, E. Olmedo, G. Debarge, “Multiple-Stokes stimulated Brillouin scattering generation in pulsed high-power double-cladding Er3+Yb3+ codoped fibre amplifier,” IEEE Photon. Technol. Lett. 15, 801–803 (2003).
[CrossRef]

Olsson, F. A.

Overbeck, J.

Panter, P. F.

P. F. Panter, Modulation, Noise, and Spectral Analysis, (McGraw-Hill, New York, 1965), Sect. 5.9.

Pearson, G. N.

Peterson, R. D.

Phillips, M. W.

M. W. Phillips, S. M. Hannon, P. G. Wanninger, P. J. M. Suni, A. L. Thomson, R. D. Richmond, “Range Doppler imaging with a coherent laser radar based upon optical fiber amplifiers,” in Coherent Laser Radar: Technology and Application, Vol. 191995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), paper ThA2, pp. 250–253.

Pinson, J. T.

K. F. Hulme, B. S. Collins, G. D. Constant, J. T. Pinson, “A CO2 laser rangefinder using heterodyne detection and chirp pulse compression,” Opt. Quantum Electron. 13, 35–45 (1981).
[CrossRef]

Player, B. E.

Plenty, R. V.

Renhorn, I.

Reynolds, A. H.

A. H. Reynolds, “CO2 ladar modulation trade-off studies,” in Coherent Infrared Radar Systems and Applications II, R. C. Harney, ed., Proc. SPIE415, 155–165 (1983).
[CrossRef]

Richards, R. K.

Richardson, D. J.

Richmond, R. D.

M. W. Phillips, S. M. Hannon, P. G. Wanninger, P. J. M. Suni, A. L. Thomson, R. D. Richmond, “Range Doppler imaging with a coherent laser radar based upon optical fiber amplifiers,” in Coherent Laser Radar: Technology and Application, Vol. 191995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), paper ThA2, pp. 250–253.

Ridley, K. D.

Rihaczek, A. W.

A. W. Rihaczek, Principles of High-Resolution Radar (Artech House, Norwood, Mass., 1996).

Roberts, P. J.

Salisbury, M. S.

Schepler, K. L.

Shapiro, J. H.

Simpson, M. L.

Sitter, D. N.

Smith, G.

Steinvall, O.

Stoneman, R.

S. M. Hannon, J. A. Thomson, S. W. Henderson, P. Gatt, R. Stoneman, D. Bruns, “Agile multiple pulse coherent lidar for range and micro-Doppler measurement,” in Laser Radar Technology and Applications III, G. W. Kamerman, ed., Proc. SPIE3380, 259–264 (1998).
[CrossRef]

Suni, P. J. M.

M. W. Phillips, S. M. Hannon, P. G. Wanninger, P. J. M. Suni, A. L. Thomson, R. D. Richmond, “Range Doppler imaging with a coherent laser radar based upon optical fiber amplifiers,” in Coherent Laser Radar: Technology and Application, Vol. 191995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), paper ThA2, pp. 250–253.

Taverner, D.

Thomson, A. L.

M. W. Phillips, S. M. Hannon, P. G. Wanninger, P. J. M. Suni, A. L. Thomson, R. D. Richmond, “Range Doppler imaging with a coherent laser radar based upon optical fiber amplifiers,” in Coherent Laser Radar: Technology and Application, Vol. 191995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), paper ThA2, pp. 250–253.

Thomson, J. A.

S. M. Hannon, J. A. Thomson, S. W. Henderson, P. Gatt, R. Stoneman, D. Bruns, “Agile multiple pulse coherent lidar for range and micro-Doppler measurement,” in Laser Radar Technology and Applications III, G. W. Kamerman, ed., Proc. SPIE3380, 259–264 (1998).
[CrossRef]

Umasuthan, M.

Walker, A.

Wallace, A.

Wanninger, P. G.

M. W. Phillips, S. M. Hannon, P. G. Wanninger, P. J. M. Suni, A. L. Thomson, R. D. Richmond, “Range Doppler imaging with a coherent laser radar based upon optical fiber amplifiers,” in Coherent Laser Radar: Technology and Application, Vol. 191995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), paper ThA2, pp. 250–253.

Watson, E. A.

Willard, B. C.

Williams, K.

Zayhowski, J. J.

Appl. Opt. (14)

J. Massa, G. Buller, A. Walker, G. Smith, S. Cova, M. Umasuthan, A. Wallace, “Optical design and evaluation of a three-dimensional imaging and ranging system based on time-correlated single-photon counting,” Appl. Opt. 41, 1063–1070 (2002).
[CrossRef] [PubMed]

M. A. Albota, R. M. Heinrichs, D. G. Kocher, D. G. Fouche, B. E. Player, M. E. OBrien, B. F. Aull, J. J. Zayhowski, J. Mooney, B. C. Willard, R. R. Carlson, “Three-dimensional imaging laser radar with a photon-counting avalanche photodiode array and microchip laser,” Appl. Opt. 41, 7671–7678 (2002).
[CrossRef]

M. J. Halmos, D. M. Henderson, R. L. Duvall, “Pulse compression of an FM chirped CO2 laser,” Appl. Opt. 28, 3595–3602 (1989).
[CrossRef] [PubMed]

C. J. Karlsson, F. A. Olsson, “Linearization of the frequency sweep of a frequency-modulated continuous-wave semiconductor laser radar and the resulting ranging performance,” Appl. Opt. 38, 3376–3386 (1999).
[CrossRef]

R. D. Peterson, K. L. Schepler, “Timing modulation of a 40-MHz laser-pulse train for target ranging and identification,” Appl. Opt. 42, 7191–7196 (2003).
[CrossRef]

J. Overbeck, M. S. Salisbury, M. B. Mark, E. A. Watson, “Required energy for a laser radar system incorporating a fiber amplifier or an avalanche photodiode,” Appl. Opt. 34, 7724–7730 (1995).
[CrossRef] [PubMed]

O. Steinvall, “Effects of target shape and reflection on laser radar cross sections,” Appl. Opt. 39, 4381–4391 (2000).
[CrossRef]

M. L. Simpson, C. A. Bennett, M. S. Emery, D. P. Hutchinson, G. H. Miller, R. K. Richards, D. N. Sitter, “Coherent imaging with two-dimensional focal-plane arrays: design and applications,” Appl. Opt. 36, 6913–6920 (1997).
[CrossRef]

J. H. Shapiro, B. A. Capron, R. C. Harney, “Imaging and target detection with a heterodyne-reception optical radar,” Appl. Opt. 20, 3292–3313 (1981).
[CrossRef] [PubMed]

H. Ahlberg, S. Lundqvist, D. Letalick, I. Renhorn, O. Steinvall, “Imaging Q-switched CO2 laser radar with heterodyne detection: design and evaluation,” Appl. Opt. 25, 2891–2897 (1986).
[CrossRef]

C. J. Karlsson, F. A. Olsson, D. Letalick, M. Harris, “All-fiber multifunction continuous-wave coherent laser radar at 1.55 μm for range, speed, vibration, and wind measurements,” Appl. Opt. 39, 3716–3726 (2000).
[CrossRef]

M. Harris, G. N. Pearson, K. D. Ridley, C. J. Karlsson, F. A. Olsson, D. Letalick, “Single-particle laser Doppler anemometry at 1.55 μm,” Appl. Opt. 40, 969–973 (2001).
[CrossRef]

G. N. Pearson, P. J. Roberts, J. R. Eacock, M. Harris, “Analysis of the performance of a coherent pulsed fiber lidar for aerosol backscatter applications,” Appl. Opt. 41, 6442–6450 (2002).
[CrossRef] [PubMed]

R. G. Frehlich, M. J. Kavaya, “Coherent laser radar performance for general atmospheric refractive turbulence,” Appl. Opt. 30, 5325–5352 (1991).
[CrossRef] [PubMed]

IEEE Photon. Technol. Lett. (1)

G. Kulcsar, Y. Jaouen, G. Canat, E. Olmedo, G. Debarge, “Multiple-Stokes stimulated Brillouin scattering generation in pulsed high-power double-cladding Er3+Yb3+ codoped fibre amplifier,” IEEE Photon. Technol. Lett. 15, 801–803 (2003).
[CrossRef]

Opt. Lett. (1)

Opt. Quantum Electron. (1)

K. F. Hulme, B. S. Collins, G. D. Constant, J. T. Pinson, “A CO2 laser rangefinder using heterodyne detection and chirp pulse compression,” Opt. Quantum Electron. 13, 35–45 (1981).
[CrossRef]

Other (6)

S. M. Hannon, J. A. Thomson, S. W. Henderson, P. Gatt, R. Stoneman, D. Bruns, “Agile multiple pulse coherent lidar for range and micro-Doppler measurement,” in Laser Radar Technology and Applications III, G. W. Kamerman, ed., Proc. SPIE3380, 259–264 (1998).
[CrossRef]

A. H. Reynolds, “CO2 ladar modulation trade-off studies,” in Coherent Infrared Radar Systems and Applications II, R. C. Harney, ed., Proc. SPIE415, 155–165 (1983).
[CrossRef]

M. W. Phillips, S. M. Hannon, P. G. Wanninger, P. J. M. Suni, A. L. Thomson, R. D. Richmond, “Range Doppler imaging with a coherent laser radar based upon optical fiber amplifiers,” in Coherent Laser Radar: Technology and Application, Vol. 191995 OSA Technical Digest Series (Optical Society of America, Washington, D.C., 1995), paper ThA2, pp. 250–253.

A. V. Jelalian, Laser Radar (Artech House, Boston, Mass., 1991).

A. W. Rihaczek, Principles of High-Resolution Radar (Artech House, Norwood, Mass., 1996).

P. F. Panter, Modulation, Noise, and Spectral Analysis, (McGraw-Hill, New York, 1965), Sect. 5.9.

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Figures (10)

Fig. 1
Fig. 1

Predicted power SNR versus range. See text for the parameter values.

Fig. 2
Fig. 2

Schematic diagram of the experimental arrangement. The dashed fiber network was used to simulate the lidar waveforms in a controlled manner for the initial characterization of the frequency modulation and signal processing. δ Pol, in-fiber polarization controller.

Fig. 3
Fig. 3

(A) Drive waveform employed to sweep the frequency of the laser source. (B) The heterodyne signal resulting from the frequency-swept portion of the laser output mixing with a constant-frequency portion of the laser output that was delayed in time by use of an 8-km fiber delay line. In this case the AOM was driven with the CW rf at 80 MHz. When the AOM was gated, the vertical lines indicate the temporal position of the section of laser output that was selected. (C) The frequency versus time of the waveform shown in (B). We evaluated this by forming a complex time series in software and numerically evaluating successive phase differences.

Fig. 4
Fig. 4

Pulse detected after propagating through the two-stage EDFA. (B) The balanced receiver output for a single pulse. (A) The result of our squaring and averaging 100 of these single pulses. See text for further details.

Fig. 5
Fig. 5

(A) Example of the correlation time series obtained with the in-fiber characterization. (B) The delayed peak shown in more detail.

Fig. 6
Fig. 6

Data extracted from multiple traces similar to the one shown in Fig. 5. In each case the peak of the correlation function (ignoring all points in the first 100 ns) was taken, and good shots were defined as ones where the peak value was at one of two time bins (4882 and 4883 ns) that straddled the correlation peak.

Fig. 7
Fig. 7

Two sections of a single time series recorded in lidar mode with the optics directed at a wall at a range of approximately 240 m. (A) The backscatter of the outgoing pulse that was used as a reference in the correlation processing. (B) The return from the target.

Fig. 8
Fig. 8

Data from 697 individual laser pulses recorded over a time period of approximately 1 min. The target was the wall of a building at a range of approximately 1.66 km. (A) The average of 697 individual correlation functions plotted as return power versus range. The SNR was approximately 30. (B) A histogram of the peak values of the individual correlation functions; 88% of the traces yielded peaks in the five range bins of 1.6590 − 1.6596 km.

Fig. 9
Fig. 9

Images of a scene consisting of a house set in trees on the side of a hill at a nominal range of approximately 1.6 km. Each image consisted of 50 × 75 pixels with an interpixel step of 0.25 mrad. (A), (B), and (D) Three lidar images. (C) A photograph of the scene. (A), (B), and (D) show images for 1-, 2-, and 10-pulse averages per pixel where we averaged the individual correlation functions prior to assessing the peak. In (A), (B), and (D) the color scale was assigned to a 300-m range depth approximately centered on the house in the middle of the frame. In (E) and (F) the 10-shot averaged image of (D) is shown with the color scale assigned to a 150- and 12-m range depth, respectively.

Fig. 10
Fig. 10

Distribution of intensities for all 3750 pixels of the 1-pulse/pixel image shown in Fig. 9(A).

Equations (5)

Equations on this page are rendered with MathJax. Learn more.

SNR = η T 2 R P A π h ν B r 2 .
S E ( ω ) = 4 stp ( ω ) S X ( ω ) ,
E ( t ) = a f ( t ) + b e i θ f ( t - t d ) + N ( t ) ,
ρ ( τ ) = E ( t ) E * ( t + τ ) d t .
ρ ( τ ) = a 2 r ( τ ) + a b e - i θ r ( τ - t d ) + a f ( t ) N * ( t + τ ) d t + a N ( t ) f * ( t + τ ) d t + N ( t ) N * ( t + τ ) d t ,

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