Abstract

A new lidar scheme using a pseudorandom code modulated cw laser as a transmitting laser source (RM-CW lidar) is proposed and a demonstration of its use for aerosol measurement is shown. A formula for estimating the SNR values in RM-CW lidar was derived, and it was demonstrated that the observed SNR value was in good agreement with the calculation.

© 1983 Optical Society of America

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References

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  1. E. D. Hinkley, Ed., Laser Monitoring of the Atmosphere (Springer, New York, 1976).
    [CrossRef]
  2. Y. E. Lee, Statistical Theory of Communication (Wiley, New York, 1960).
  3. R. A. Ferguson, “Feasibility Study of a cw Lidar Technique for Measurement of Plume Opacity,” Final Report SRI project 1979, EPA no. 650/2-73/037 (Nov.1973).
  4. M. I. Skolnik, Ed., Radar Handbook (McGraw-Hill, New York, 1970), Chap. 16.
  5. T. Sakamoto, Y. Taki, H. Miyakawa, T. Suzuki, H. Kobayashi, T. Kanda, J. Inst. Electron. Commun. Eng. Jpn. 46, 155 (1963), in Japanese.
  6. S. E. Craig, W. Fishbein, O. E. Ritenbach, IRE Trans. on Military Electr. MIL-6, 153 (1962).
    [CrossRef]
  7. J. Harms, Appl. Opt. 18, 1559 (1979).
    [CrossRef] [PubMed]
  8. Y. Sasano, H. Shimizu, N. Takeuchi, M. Okuda, Appl. Opt. 18, 3908 (1979).
    [CrossRef] [PubMed]
  9. D. C. O’Shea, L. G. Dodge, Appl. Opt. 13, 1481 (1974).
    [CrossRef]
  10. H. Baba, K. Sakurai, F. Shimizu, to be published in Rev. Sci. Instrum.April (1983).
  11. In the case of photon counting, a theory (Ref. 10) gives the counting efficiency in the form ζ=[1−exp(n¯Δt)]/n¯Δt, where n¯ is the average count of incident photons/sec and Δt is the unit gate time. The error limit of 10% in ζ corresponds to n¯Δt being 0.2, which gives n¯ to be 106 photons/sec for Δt = 200 nsec. This situation was attained by raising the discrimination level.
  12. R. C. Dixon, Spread Spectrum Systems (Wiley, New York, 1976).

1979

1974

1963

T. Sakamoto, Y. Taki, H. Miyakawa, T. Suzuki, H. Kobayashi, T. Kanda, J. Inst. Electron. Commun. Eng. Jpn. 46, 155 (1963), in Japanese.

1962

S. E. Craig, W. Fishbein, O. E. Ritenbach, IRE Trans. on Military Electr. MIL-6, 153 (1962).
[CrossRef]

Baba, H.

H. Baba, K. Sakurai, F. Shimizu, to be published in Rev. Sci. Instrum.April (1983).

Craig, S. E.

S. E. Craig, W. Fishbein, O. E. Ritenbach, IRE Trans. on Military Electr. MIL-6, 153 (1962).
[CrossRef]

Dixon, R. C.

R. C. Dixon, Spread Spectrum Systems (Wiley, New York, 1976).

Dodge, L. G.

Ferguson, R. A.

R. A. Ferguson, “Feasibility Study of a cw Lidar Technique for Measurement of Plume Opacity,” Final Report SRI project 1979, EPA no. 650/2-73/037 (Nov.1973).

Fishbein, W.

S. E. Craig, W. Fishbein, O. E. Ritenbach, IRE Trans. on Military Electr. MIL-6, 153 (1962).
[CrossRef]

Harms, J.

Kanda, T.

T. Sakamoto, Y. Taki, H. Miyakawa, T. Suzuki, H. Kobayashi, T. Kanda, J. Inst. Electron. Commun. Eng. Jpn. 46, 155 (1963), in Japanese.

Kobayashi, H.

T. Sakamoto, Y. Taki, H. Miyakawa, T. Suzuki, H. Kobayashi, T. Kanda, J. Inst. Electron. Commun. Eng. Jpn. 46, 155 (1963), in Japanese.

Lee, Y. E.

Y. E. Lee, Statistical Theory of Communication (Wiley, New York, 1960).

Miyakawa, H.

T. Sakamoto, Y. Taki, H. Miyakawa, T. Suzuki, H. Kobayashi, T. Kanda, J. Inst. Electron. Commun. Eng. Jpn. 46, 155 (1963), in Japanese.

O’Shea, D. C.

Okuda, M.

Ritenbach, O. E.

S. E. Craig, W. Fishbein, O. E. Ritenbach, IRE Trans. on Military Electr. MIL-6, 153 (1962).
[CrossRef]

Sakamoto, T.

T. Sakamoto, Y. Taki, H. Miyakawa, T. Suzuki, H. Kobayashi, T. Kanda, J. Inst. Electron. Commun. Eng. Jpn. 46, 155 (1963), in Japanese.

Sakurai, K.

H. Baba, K. Sakurai, F. Shimizu, to be published in Rev. Sci. Instrum.April (1983).

Sasano, Y.

Shimizu, F.

H. Baba, K. Sakurai, F. Shimizu, to be published in Rev. Sci. Instrum.April (1983).

Shimizu, H.

Suzuki, T.

T. Sakamoto, Y. Taki, H. Miyakawa, T. Suzuki, H. Kobayashi, T. Kanda, J. Inst. Electron. Commun. Eng. Jpn. 46, 155 (1963), in Japanese.

Takeuchi, N.

Taki, Y.

T. Sakamoto, Y. Taki, H. Miyakawa, T. Suzuki, H. Kobayashi, T. Kanda, J. Inst. Electron. Commun. Eng. Jpn. 46, 155 (1963), in Japanese.

Appl. Opt.

IRE Trans. on Military Electr.

S. E. Craig, W. Fishbein, O. E. Ritenbach, IRE Trans. on Military Electr. MIL-6, 153 (1962).
[CrossRef]

J. Inst. Electron. Commun. Eng. Jpn.

T. Sakamoto, Y. Taki, H. Miyakawa, T. Suzuki, H. Kobayashi, T. Kanda, J. Inst. Electron. Commun. Eng. Jpn. 46, 155 (1963), in Japanese.

Other

H. Baba, K. Sakurai, F. Shimizu, to be published in Rev. Sci. Instrum.April (1983).

In the case of photon counting, a theory (Ref. 10) gives the counting efficiency in the form ζ=[1−exp(n¯Δt)]/n¯Δt, where n¯ is the average count of incident photons/sec and Δt is the unit gate time. The error limit of 10% in ζ corresponds to n¯Δt being 0.2, which gives n¯ to be 106 photons/sec for Δt = 200 nsec. This situation was attained by raising the discrimination level.

R. C. Dixon, Spread Spectrum Systems (Wiley, New York, 1976).

E. D. Hinkley, Ed., Laser Monitoring of the Atmosphere (Springer, New York, 1976).
[CrossRef]

Y. E. Lee, Statistical Theory of Communication (Wiley, New York, 1960).

R. A. Ferguson, “Feasibility Study of a cw Lidar Technique for Measurement of Plume Opacity,” Final Report SRI project 1979, EPA no. 650/2-73/037 (Nov.1973).

M. I. Skolnik, Ed., Radar Handbook (McGraw-Hill, New York, 1970), Chap. 16.

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Figures (5)

Fig. 1
Fig. 1

Example of M sequence (N = 15).

Fig. 2
Fig. 2

Schematic explanation of RM-CW lidar.

Fig. 3
Fig. 3

Block diagram of the experimental setup.

Fig. 4
Fig. 4

Example of RM-CW lidar measurement. Two optical axes of the transmitter and the laser crossed due to the nonparallelism of 4-mrad tilting. The crossover function Y(R) is shown by a dashed line. Two curves are adjusted to have the same initial slope at R = 0.85 km.

Fig. 5
Fig. 5

Example of RM-CW lidar measurement. Solid line is a theoretical fit of lidar return signal (absolute value is normalized to the experimental data). Dashed line shows the estimated crossover function Y(R), which is adjusted to have the same initial slope at R = 2.5 km with the lidar return signal.

Tables (1)

Tables Icon

Table 1 Features of the RM-CW Lidar

Equations (21)

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z ( t ) = 0 T x ( t t ) g ( t ) d t + b ( t ) .
g ( t ) = η ( c / 2 ) A r β r ( R ) T r ( R ) 2 Y ( R ) / R 2 ,
R = c t / 2 .
z ( t ) = P p t p g ( t ) + b ( t ) ,
x ( t t ) = P O a ( t t ) .
a ( t ) = i = 1 N a i · ( t i Δ t ) [ i ( modulo N ) ] , a i = 1 or 0 , ( t ) = 1 ( 0 t < Δ t ) ; 0 ( otherwise ) .
Ψ a , a ( j ) = 1 N i = 1 N a i a i + j = { 1 for j = 0 1 / N for j 0.
Ψ a , a ( j ) = 1 N i = 1 N a i a i + j = { ( N + 1 ) / 2 N l / N for j = 0 0 for j 0 ,
z ( t ) = i = 1 N z i · ( t i Δ t ) ,
b ( t ) = i = 1 N b i · ( t i Δ t ) ,
G ( t ) = g ( t ) Δ t = i = 1 N G i · ( t i Δ t ) ,
z i = P O j a i j G j + b i .
E ( A ) = A ˜ ( 1 / M ) m = 1 M A m ,
S j = N Ψ a , z ( j ) = i = 1 N a i + j z i = l P o G ¯ j + i = 1 N a i + j b i .
V j = E { [ l P o ( G j G ˜ j ) ] 2 } = E { [ i = 1 N a i j ( z i z ˜ i ) ] 2 } + E { [ i = 1 N a i j ( b b ˜ i ) ] 2 } = i = 1 N E [ ( z i z ˜ i ) 2 ] + i = 1 N E [ ( b i b ˜ i ) 2 ] .
ξ 2 E [ ( z i z ˜ i ) 2 ] = ξ z ˜ i ,
ξ 2 E [ ( b i b ˜ i ) 2 ] = ξ b ˜ i ,
V j = ( 1 / ξ ) ( i = 1 N z ˜ i + N b ¯ ) ,
V j = ( 1 / ξ ) [ i = 1 N ( P 0 k = 1 N a i k G ˜ k + b ˜ i ) + N b ¯ ] = ( 1 / ξ ) ( P 0 l k = 1 N G ˜ k + 2 N b ¯ ) = ( N / ξ ) ( P 0 l G ¯ + 2 b ¯ ) ,
( S / N ) RM = M × S j / V j = M ξ l P 0 G ˜ j l P 0 G ˜ + 2 b ¯ .
( S / N ) pulse = M ξ P p g ˜ j t p P p g ˜ j t p + 2 b ¯ .

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