**4. Data analysis and simulation results**

Model calculations based on the data obtained by the laser probing of the atmosphere by means of system I with an output power equal to 0.67 mW (Ashkinadze, D. A., Belobrovik, V. P., Spiridovich, A. L., Kugeiko, M. M. and Polknov, Y. A., 1980; Ashkinadze, D. A and Polkanov, Y. A., 1980; Polkanov, Y. A. et al., 1985; Polkanov, Y. A and Ashkinadze D. A., 1988; Polkanov, Y. A. et al., 1991).

The results of real lidar measurements are used to model the time organization of the proposed emission and detection. Lidar has the following characteristics:

• Radiation source:

Radiation energy E = 0.01 J;

Pulse duration To = 15 ns;

Pulse repetition frequency f = 50 Hz.

• Receiving system:

Diameter of the receiving mirror D = 0.1 m;

Operation of a photomultiplier tube (PMT) - an account of the photons;

Quantum efficiency of PMT η = 0,1;

• Recording equipment:

Time interval signal detection in single channel ti = 0,4 mkc;

Number of cycles of signal m – 3000;

Total measurement time t = 60 s (Polkanov, Y. A. et al., 1985).

The measurement conditions corresponded to the registration of a Poisson flow of the signal photons (Polkanov, Y. A., 1983). The number of the cycles of the accumulation provided a measurement error of no worse than 50%.

Fig. 1. The lidar scheme, with a separated transmitter and receiver.

The simulation results are presented as a set of tables.

Model calculations based on the data obtained by the laser probing of the atmosphere by means of system I with an output power equal to 0.67 mW (Ashkinadze, D. A., Belobrovik, V. P., Spiridovich, A. L., Kugeiko, M. M. and Polknov, Y. A., 1980; Ashkinadze, D. A and Polkanov, Y. A., 1980; Polkanov, Y. A. et al., 1985; Polkanov, Y. A and Ashkinadze D. A.,

The results of real lidar measurements are used to model the time organization of the

The measurement conditions corresponded to the registration of a Poisson flow of the signal photons (Polkanov, Y. A., 1983). The number of the cycles of the accumulation provided a

proposed emission and detection. Lidar has the following characteristics:

Operation of a photomultiplier tube (PMT) - an account of the photons;

Time interval signal detection in single channel ti = 0,4 mkc;

Total measurement time t = 60 s (Polkanov, Y. A. et al., 1985).

Fig. 1. The lidar scheme, with a separated transmitter and receiver.

The simulation results are presented as a set of tables.

**4. Data analysis and simulation results** 

1988; Polkanov, Y. A. et al., 1991).

• Radiation source:

• Receiving system:

Radiation energy E = 0.01 J; Pulse duration To = 15 ns;

Pulse repetition frequency f = 50 Hz.

Quantum efficiency of PMT η = 0,1;

Number of cycles of signal m – 3000;

measurement error of no worse than 50%.

• Recording equipment:

Diameter of the receiving mirror D = 0.1 m;

#### **4.1 The simulation results of the proposed temporal organisation of the detected signal**

We shall call this remote sensing system (lidar) as a base 'System I' (the old system), and a system with increasing intervals of registration (strob) 'System II' (the new system).

Fig. 2. Discrete-time signal xc(t) processing for System I.

Fig. 3. Discrete-time signal xc(t) processing for System II (T1 = T, T2 = 2T, T3 = 3T, T4 = 4T).

The calculation of the signal/background ratio and the corresponding measurement errors of the scattering signal is carried to the appropriate conditions of 'twilight' (∂1) and 'cloudy day' (∂2) when the level of background illumination increases by two orders of magnitude. The following table shows the dynamic range (DR) and signal/background ratio for the a wide range length of the path sounding (L) for each value of the extinction coefficient (σ) from the real range. The level of illumination is selected for the corresponding conditions with a high transparency of the atmosphere (~ 10-2 km-1).

Looking at Remote Sensing the Timing of an

daytime.

data.

is much smaller than in the case of system I (DR = 8 - 34). The data obtained suggests the following conclusions:

redundant requirements for its performance.

section of the remote sensor.

Organisation's Point of View and the Anticipation of Today's Problems 225

errors of the detecting apparatus. The error increases with the daytime measurements (at the same transparency), but by no more than an order of magnitude; its increase is insignificant for the extinction coefficient range σ = 1-10 km-1. The dynamic range of the signal/background ratio is small and varies with changing conditions in the atmosphere; it

1. The use of 'growing' of the proposed type of strobe allows for the measurement of the single-scattering signal with a high precision. Measurements become possible in the

2. Small dynamic range of the signal/background ratio will simplify the recording equipment without compromising the accuracy of the measurement by eliminating any

3. The use of this approach shifts the problem of increasing the measurement accuracy from the area associated with the environment to the area associated only with the

The accuracy varies slightly from a strobe to strobe on most of the track soundings. This provides significant advantages for the correctness of the subsequent interpretation of the

Fig. 5. Normalised error of measurement, depending upon the length of the path sounding.

The analysis of the dynamic range of the scattering signal also shows the advantages of system II. The dynamic range of the signal does not exceed the value 102, compared with value 106 for systems of type I. Table 5 shows the value (DR) of the scattering signal and the background level for system II. In our case, the range for backlight can reach 103, remaining

several orders of magnitude lower than for the scattering signal of system I.

instrumental capabilities of the remote systems (i.e. they are more controlled). 4. An additional advantage of the developed approach is the small dynamic range of change of the error signal scattering, depending upon the distance to the considered

Fig. 4. Organisation model of the discrete-time signal processing.


Table 3. The measurement error (∂) of the signal/noise ratio (S/N) and the dynamic range (DR), depending upon the length of the path sounding (L) and the extinction coefficient of the medium (σ).

The measurement error of these conditions is calculated by formula (1) and does not exceed a few percent. For most cases, we can assume that it will be less then common instrument

**(km-1) L(km) 1 2 3 4 5 10 15 30 DR**  s/n 19,00 9,40 6,50 5,00 4,00 3,00 1,30 0,60 29 0.01 ∂1 (%) 2,60 2,10 2,01 2,03 2,06 2,36 2,62 3,29 29

∂2 (%) 8,34 8,87 9,94 11,10 12,15 17,21 20,69 28,75 29

∂2 (%) 1,24 1,25 1,36 1,51 1,65 2,29 2,79 2,97 34

∂2 (%) 0,70 0,66 0,63 0,87 0,95 1,26 1,52 1,61 23

∂2 (%) 0,63 0,77 0,87 0,98 1,06 8

∂2 (%) 0,05 0,05 0,05 0,05 0,05 8

 s/n 164,30 82,30 54,80 40,00 31,80 15,10 9,90 4,80 34 0.1 ∂1 (%) 0,84 0,66 0,63 0,63 0,63 0,63 0,65 0,66 34

 s/n 363,60 166,70 106,00 75,50 59,40 27,70 18,10 15,90 23 0.3 ∂1 (%) 0,56 0,46 0,44 0,44 0,44 0,44 0,45 0,46 23

 s/n 419,80 156,80 94,80 66,70 52,10 8 1.0 ∂1 (%) 0,52 0,46 0,46 0,47 0,47 8

σ(km-1) L(km) 0.1 0.2 0.3 0.4 0.5 8 s/n 420000 156000 95000 66000 52000 8 10.0 ∂1 (%) 0,05 0,05 0,05 0,05 0,05 8

Table 3. The measurement error (∂) of the signal/noise ratio (S/N) and the dynamic range (DR), depending upon the length of the path sounding (L) and the extinction coefficient of

The measurement error of these conditions is calculated by formula (1) and does not exceed a few percent. For most cases, we can assume that it will be less then common instrument

Fig. 4. Organisation model of the discrete-time signal processing.

**σ**

the medium (σ).

errors of the detecting apparatus. The error increases with the daytime measurements (at the same transparency), but by no more than an order of magnitude; its increase is insignificant for the extinction coefficient range σ = 1-10 km-1. The dynamic range of the signal/background ratio is small and varies with changing conditions in the atmosphere; it is much smaller than in the case of system I (DR = 8 - 34).

The data obtained suggests the following conclusions:


The accuracy varies slightly from a strobe to strobe on most of the track soundings. This provides significant advantages for the correctness of the subsequent interpretation of the data.

Fig. 5. Normalised error of measurement, depending upon the length of the path sounding.

The analysis of the dynamic range of the scattering signal also shows the advantages of system II. The dynamic range of the signal does not exceed the value 102, compared with value 106 for systems of type I. Table 5 shows the value (DR) of the scattering signal and the background level for system II. In our case, the range for backlight can reach 103, remaining several orders of magnitude lower than for the scattering signal of system I.

Looking at Remote Sensing the Timing of an

calculation was performed as follows:

on the basis of the obtained values, ΔL.

nanoseconds (in the zone of single scattering).

**radiation** 

(type I).

2010).

track at a distance L.

1. A constant increment of the scattering signal ΔPs is posed.

determined on the basis of the intervals' increment, Δts

= 15km, for σ = 0.3 km-1 to L = 5 km, and for σ = 1 km-1 to L = 4 km.

Organisation's Point of View and the Anticipation of Today's Problems 227

To estimate the limiting possibilities of system II, we calculated the allowable spatial resolution of the remote sensing under various conditions in the atmosphere. The

2. The increment area sounding (ΔL) which provided a signal increment (ΔPs) for certain values of the extinction coefficient (σ) and the length of track is then identified. 3. The increment ΔL thereby obtained is taken as the minimum spatial discretisation step

4. The necessary step time sampling rate is determined for the recording equipment (Δts)

5. The increment background illumination (the number of the background count ΔPb) is

To estimate the limiting possibilities of system II, we calculated the valid value of the spatial resolutions under various conditions in the atmosphere. The calculation was performed as follows: the value of ΔPs given as the number of samples (100, 10, 1), with the transition from one value to another. The value ΔPs does not exceed step ΔL spatial discretisation achieved the basic apparatus in version of the system I. The calculation results for W0 = 0.67 mW are shown by Table 6. The increments ΔPs certainly took higher increments due to the internal noise receiver. This was the case for σ = 10-2 km-1 to L = 30 km, for σ = 0.1 km-1 to L

We have exceeded ΔPs over ΔPb in all cases (to dusk) when ΔPc = 100, 10. This is much less than was the case for system I. The simulation results suggest that there is a real opportunity to provide the increment of the scattering signal on the increment of the recorded background illumination (ΔPs> ΔPb) for a wide range of conditions by the adjustment of the values Δt. At the same time, the allowed (minimum) time increments Δts (increments for the individual remote-sensing signal samples) do not exceed – in this case – hundreds of

**4.2 The simulation results of the proposed organisation of the sounding signal** 

organisation of the radiation of the sounding signal (in the case of active systems).

We consider three types of organisation of the radiation source:

The proposed approach can be applied not only to the organisation of the temporary registration of the incoming signal (in the case of passive systems), but also to the temporary

• Pulsed light source (laser) with a pulse substantially shorter than the sounding track

• Pulsed light source (laser) with a pulse substantially equal the sounding track (type II). • Long pulsed light source with a repetition-rate that ensures the duration of the interval between the pulses is equal or near to the pulse length of type I (type III), dark pulse laser (Mingming, Feng, Kevin L. Silverman, Richard P. Mirin and Steven T. Cundiff,

Again, asAs before, the basic system is taken to be a real system of type I (V. E. Zuev, M. V. Kabanov, 1977) with a constant duration of strobe (ts = 0.4 ms) and the characteristics


Table 4. The number of the signal count (ns) and the background (nb) for the photon counting mode, and the dynamic range (DR), depending upon the extinction coefficient of the medium (σ).


Table 5. The required increase of the signal sampling interval (space, time) which provided the desired signal increase and its corresponding background increase.

**σ(km-1) L(km) 1 30 DR 0.01** signal 6462 15600 72 **0.01** background (noise) 850 25000 900 **σ (km-1) L(km) 1 2 DR 0.1** signal 57580 113730 59 **0.1** background (noise) 850 25000 900 **σ(km-11) L(km) 1 17 DR 0.3** signal 127465 217625 29 **0.3** background (noise) 850 14150 283 **σ (km-1) L(km) 1 2 DR 1** signal 147150 190310 6,5 **1** background (noise) 850 4150 24,4 **σ (km-1) L(km) 0,1 0,5 DR 10** signal 14739000 19004096 6,4 **10** background (noise) 85 415 24,4

Table 4. The number of the signal count (ns) and the background (nb) for the photon counting mode, and the dynamic range (DR), depending upon the extinction coefficient of

Δls(m) 0,6 4,4 18,0 60,0 190,0

ΔPnng 0б5 3б7 15,0 50,0 158,0

Table 5. The required increase of the signal sampling interval (space, time) which provided

**0.3** Δts(ns) 4 29 120 400 1270

Δls(m) 0,7 21,7 730,0 50,0 **1.0** Δts(ns) 4,7 145,0 4870,0 333,0 ΔPnbg 0б6 18,0 608,0 42

Δls(m) - 0,3 3,9 6,0

ΔPnbg - 0,2 2,6 5,0

the desired signal increase and its corresponding background increase.

**σ(km-1) L(km) 0.1 0.2 0.3 0.4** 

**10.0** Δts(ns) - 2 26 40,0

**σ(km-1) L(km) 1 2 3 4 5 10 15 30** 

**0.01** Δts(ns) 67 287 647 120 193 233 2130 1130

Δls(m) 10 43 97 18 29 125 320 169

ΔPnbg 8 36 81 15 24 104 26 141 Δls(m) 2 6 16 36 70 40 500 9700 **0.1** Δts(ns) 13 40 107 240 467 266 3300 64700 ΔPbg 2 5 13 30 58 733 417 8083

**N ex.n. = 0,3** 

**ΔPs > ΔРex.n.** 

**ΔPs = 100, 10, 1**

the medium (σ).

To estimate the limiting possibilities of system II, we calculated the allowable spatial resolution of the remote sensing under various conditions in the atmosphere. The calculation was performed as follows:


To estimate the limiting possibilities of system II, we calculated the valid value of the spatial resolutions under various conditions in the atmosphere. The calculation was performed as follows: the value of ΔPs given as the number of samples (100, 10, 1), with the transition from one value to another. The value ΔPs does not exceed step ΔL spatial discretisation achieved the basic apparatus in version of the system I. The calculation results for W0 = 0.67 mW are shown by Table 6. The increments ΔPs certainly took higher increments due to the internal noise receiver. This was the case for σ = 10-2 km-1 to L = 30 km, for σ = 0.1 km-1 to L = 15km, for σ = 0.3 km-1 to L = 5 km, and for σ = 1 km-1 to L = 4 km.

We have exceeded ΔPs over ΔPb in all cases (to dusk) when ΔPc = 100, 10. This is much less than was the case for system I. The simulation results suggest that there is a real opportunity to provide the increment of the scattering signal on the increment of the recorded background illumination (ΔPs> ΔPb) for a wide range of conditions by the adjustment of the values Δt. At the same time, the allowed (minimum) time increments Δts (increments for the individual remote-sensing signal samples) do not exceed – in this case – hundreds of nanoseconds (in the zone of single scattering).

#### **4.2 The simulation results of the proposed organisation of the sounding signal radiation**

The proposed approach can be applied not only to the organisation of the temporary registration of the incoming signal (in the case of passive systems), but also to the temporary organisation of the radiation of the sounding signal (in the case of active systems).

We consider three types of organisation of the radiation source:


Again, asAs before, the basic system is taken to be a real system of type I (V. E. Zuev, M. V. Kabanov, 1977) with a constant duration of strobe (ts = 0.4 ms) and the characteristics

Looking at Remote Sensing the Timing of an

dark pulses (for system III).

1 Watt).

below.

Organisation's Point of View and the Anticipation of Today's Problems 229

The analysis of this data allows us can conclude that to provide the necessary signal levels due to the growth of the pulse repetition rate, the frequency of system II should be raised to 8.57 kHz, and that of for system III to 55.5 kHz. These limitations are needed so as to exclude the presence on the track sensing of the two light pulses (for systems I and II) or the

The computed frequencies provided a growing number of background counts (compared with system I) for system II (171 times) and system III (- 1100 times). Accordingly, the number of signal photon counts was increased in 51 and 2200 times. This allows us to reduce the measurement error from 33% to 7% and 0.6% respectively for systems II and III. The evaluation shows that the use of systemsusing a system of type II andor type III – even with a radiation source with a capacity of 1 Watt – can significantly improve the measurement accuracy of the scattering signal, relative to the system I (radiation power ~

Fig. 6. Normalised power systems I (old) and II (new) as a function of environmental

This is achieved through the formation of the continuous emission of long pulses (dark pulses) with a high repetition rate. It allows for a fixed measurement time (60 s) registering a much larger number of photons. Thus, we can reduce the required power of the radiation source. It is interesting estimating the maximum possible repetition rate laser pulses for system II. The pulse length varies from one pulse to the next the length of the registration strobe (single reference signal) changes from one strobe to another gate. To eliminate the effect of the scattering signal from the previous pulse, the interval between pulses (lΔ) was chosen according to the condition: σ (lΔ + MDV) = 7.5. In this case, the contribution from the previous pulses in the signal did not exceed 10% of the maximum accumulated signal. The values of the maximum possible repetition-rate of system II is represented in the table

Here, the following notation was used: lτ0 – the pulse duration τ0; lΔ - the interval between pulses in meters; f – the frequency of pulses; M – the number of the accumulation cycles; Eo

conditions (σ=0,01-1 km-1) at the same signal/noise ratio.


Table 6. The calculated characteristics of the equivalent remote-sensing systems of type I, II and III.

described above. In addition, we used data obtained by probing the system in advanced atmospherics with the extinction coefficient σ = 0.1 km-1.

The comparative evaluation of the above types of systems was carried out under the assumption used that in the future there would be a a source of continuous light source radiation with a radiated power ~ 1W, since this energy is easily attainable at the present level of the laser system development. We select a maximum . The length of the route maximises the accumulated signal for the conditions of a single scattering (τ = 2σl ≤ 3). For system III, an assumption is introduced – the interval between pulses (60 m) does not affect the accumulated signal for distances greater than the path length of the maximum accumulation (L max ~ τ = 3) (Polkanov, Y. A. et al., 2007; Polkanov, Y. A. et al., 2008).

The temporal organisation of the remote-sensing signal reception, the level of background illumination, and the total measurement time is expected the same for all the simulated systems. This data is shown by Table 7, which summarises all of the necessary characteristics for comparison.

Duration of the radiation impulse 15 ns 18 μs 18 μs Length of the radiation impulse 4.5 m 5.4 km 5.4 km Radiation Energy 0,01 J 18 μsJ 18 μJ Radiation impulse power 667 kW 1 W 1 W Registration strobe duration 0.4 μs 0.4 μs 0.4 μs Registration strobe length 60 m 60 m 60 m Strobe numbers on a line 90 90 90 Line length 5.4 km 5.4 km 5.4 km Measurement total time 60 s 60 s 60 s Number of the accumulation cycles 3000 514000 3300000 Frequency of the impulses 50 Hz 8.57 kHz 55.5 kHz Spatial interval between impulses » 5 km 30 km « 5 km Total radiation energy 30 J 9.25 J 60 J Average radiation power 0.5 W 0.15 W 1.0 W Background readout number in a strobe 50 8570 55500 Signal readout number in a strobe (min) 83 4258 182600 Measurement error 33% 7% 0.6% Background readout number/parcel 0.017 0.017 0.017

(min) 0.028 0.008 0.055

Table 6. The calculated characteristics of the equivalent remote-sensing systems of type I, II

described above. In addition, we used data obtained by probing the system in advanced

The comparative evaluation of the above types of systems was carried out under the assumption used that in the future there would be a a source of continuous light source radiation with a radiated power ~ 1W, since this energy is easily attainable at the present level of the laser system development. We select a maximum . The length of the route maximises the accumulated signal for the conditions of a single scattering (τ = 2σl ≤ 3). For system III, an assumption is introduced – the interval between pulses (60 m) does not affect the accumulated signal for distances greater than the path length of the maximum accumulation (L max ~ τ = 3) (Polkanov, Y. A. et al., 2007; Polkanov, Y. A. et al., 2008).

The temporal organisation of the remote-sensing signal reception, the level of background illumination, and the total measurement time is expected the same for all the simulated systems. This data is shown by Table 7, which summarises all of the necessary

Number of signal readout number/parcel

characteristics for comparison.

atmospherics with the extinction coefficient σ = 0.1 km-1.

and III.

**1 2 3** 

The analysis of this data allows us can conclude that to provide the necessary signal levels due to the growth of the pulse repetition rate, the frequency of system II should be raised to 8.57 kHz, and that of for system III to 55.5 kHz. These limitations are needed so as to exclude the presence on the track sensing of the two light pulses (for systems I and II) or the dark pulses (for system III).

The computed frequencies provided a growing number of background counts (compared with system I) for system II (171 times) and system III (- 1100 times). Accordingly, the number of signal photon counts was increased in 51 and 2200 times. This allows us to reduce the measurement error from 33% to 7% and 0.6% respectively for systems II and III. The evaluation shows that the use of systemsusing a system of type II andor type III – even with a radiation source with a capacity of 1 Watt – can significantly improve the measurement accuracy of the scattering signal, relative to the system I (radiation power ~ 1 Watt).

Fig. 6. Normalised power systems I (old) and II (new) as a function of environmental conditions (σ=0,01-1 km-1) at the same signal/noise ratio.

This is achieved through the formation of the continuous emission of long pulses (dark pulses) with a high repetition rate. It allows for a fixed measurement time (60 s) registering a much larger number of photons. Thus, we can reduce the required power of the radiation source. It is interesting estimating the maximum possible repetition rate laser pulses for system II. The pulse length varies from one pulse to the next the length of the registration strobe (single reference signal) changes from one strobe to another gate. To eliminate the effect of the scattering signal from the previous pulse, the interval between pulses (lΔ) was chosen according to the condition: σ (lΔ + MDV) = 7.5. In this case, the contribution from the previous pulses in the signal did not exceed 10% of the maximum accumulated signal. The values of the maximum possible repetition-rate of system II is represented in the table below.

Here, the following notation was used: lτ0 – the pulse duration τ0; lΔ - the interval between pulses in meters; f – the frequency of pulses; M – the number of the accumulation cycles; Eo

Looking at Remote Sensing the Timing of an

systems depending upon the environment (type III).

intervals of the structure of the inhomogeneities (М+, М-).

optical shutters.

12 to 17 days.

Organisation's Point of View and the Anticipation of Today's Problems 231

σ (km-1) lτ<sup>0</sup> τ0 (μs) lΔ (m) f (kHz) M E0 (μJ) W0 (W) 0,01 30,0 100 60 10 600 000 50,0 0,5 0,1 30,0 100 60 10 600 000 50,0 0,5 0,3 16,7 55,7 60 18 1 100 000 28,0 0,5 1,0 5,0 16,7 60 60 3 600 000 8,4 0,5 10,0 0,5 1,7 60 600 36 000 000 0,9 0,5 Table 8. The maximum possible pulse repetition frequency of the radiation remote-sensing

The necessary energy radiation does not exceed ten microjoules at the limiting frequencies. This suggests the use of low-power lasers as radiation sources in systems II and III, with optical shutters which open with a given frequency (f). The maximum frequency is obtained at ~ 1 MHz, but it has a range of 10-100 kHz in most cases. This is achieved by conventional

In the above conditions, the maximum pulse power of system II does not exceed 18W. For system III, the power is equal to 0.5W which is sufficient to achieve a measurement error not

We investigated the behaviour of three sample models in relation to the signal from a selforganising environment. The behaviour of the three sample models was analyzed. It has a 16-17 readout and a digitisation step - 30 minutes, with total duration of measurements from

The averaging of the intervals between local maxima and minima gives the generalised

M1+ M1-

1 2 3 4 5 6 7 8 9 10 11 12

different types, 'plus' and 'minus' (M+, M-) for some areas (1-12).

Fig. 7. Results of the interval definition between the elements of the generalised structure of

worse than tenths of a percent, excluding the errors caused by the instrument.

**4.3 The simulation results of the signal structure stability of remote-sensing** 


Table 7. The maximum possible pulse repetition frequency (f) of the radiation remotesensing systems (type II) depending upon the environment (σ).

– the energy of the radiation. This provides an accuracy that is not worse than the accuracy of the measurement system II for the same values of the extinction coefficient (σ). The number of emitted photons is equal in all the simulated cases. This corresponds to the radiation energy of system I for a full-time measurement (60 sec), which corresponds to the average power W0 = 0.5 W. This allows us to visually compare systems with different types of organisation of the radiation source. Likewise, we assessed the limiting frequencies of the pulses of radiation systems for system III. The data obtained is summarised in the following table:

**lτ0 (km)** 1 2 3 4 5 10 15 30 **τ0 (μs)** 3,3 6,7 10,0 13,3 16,7 33.0 50,0 100,0

**f (kHz)** 9,7 9,4 9,1 8,8 8,6 7,5 6,7 5,0 **M** 581 000 562 000 546 000 528 000 516 000 450 000 400 000 300 000 **E0 (μJ)** 51,6 53,4 54,9 56,8 58,1 66,7 74,6 100,0 **W0(W)** 15,6 8,0 5,5 4,3 3,5 2,0 1,5 1,0

**f (kHz)** 23,6 21,9 20,4 19,1 17,9 1`3,9 11,2 10,4 **M** 1 420 000 1 310 000 1 220 000 1 150 000 1 080 000 830 000 670 000 620 000 **E0 (μJ)** 21,0 23,0 24,0 26,0 28,0 36,0 45,0 48,0 **W0(W)** 6,4 3,4 2,5 2,0 1,7 1,1 0,9 0,8

**fE0 =const** 

**W0 = 0,5 W** 

**E(2)Σ = E(1)<sup>Σ</sup>**

**σ (km-1)** 0,01 - 0,1 **lΔ (km)** 30

**σ (km-1)** 0,3 **lΔ (km)** 11,7

**σ (km-1)** 1.0 **lΔ (km)** 3,5

**σ (km-1)** 10.0 **lΔ (km)** 0,35

> 33 000 000

**<sup>M</sup>**40 000 000

table:

**f (kHz)** 66,7 54,5 46,1 40,0 35,3 **M** 4 000 000 3 300 000 2 800 000 2 400 000 2 100 000

**E0 (μJ)** 7,5 9,2 10,8 12,5 14,2 **W0(W)** 2,3 1,4 1,1 0,9 0,8

**f (kHz)** 666,7 545,4 461,5 400,0 352,3

**E0 (μJ)** 0,7 0,9 1,1 1,2 1,4 **W0(W)** 2,3 1,4 1,1 0,9 0,8

sensing systems (type II) depending upon the environment (σ).

28 000 000

24 000 000

– the energy of the radiation. This provides an accuracy that is not worse than the accuracy of the measurement system II for the same values of the extinction coefficient (σ). The number of emitted photons is equal in all the simulated cases. This corresponds to the radiation energy of system I for a full-time measurement (60 sec), which corresponds to the average power W0 = 0.5 W. This allows us to visually compare systems with different types of organisation of the radiation source. Likewise, we assessed the limiting frequencies of the pulses of radiation systems for system III. The data obtained is summarised in the following

Table 7. The maximum possible pulse repetition frequency (f) of the radiation remote-

21 000 000


Table 8. The maximum possible pulse repetition frequency of the radiation remote-sensing systems depending upon the environment (type III).

The necessary energy radiation does not exceed ten microjoules at the limiting frequencies. This suggests the use of low-power lasers as radiation sources in systems II and III, with optical shutters which open with a given frequency (f). The maximum frequency is obtained at ~ 1 MHz, but it has a range of 10-100 kHz in most cases. This is achieved by conventional optical shutters.

In the above conditions, the maximum pulse power of system II does not exceed 18W. For system III, the power is equal to 0.5W which is sufficient to achieve a measurement error not worse than tenths of a percent, excluding the errors caused by the instrument.

## **4.3 The simulation results of the signal structure stability of remote-sensing**

We investigated the behaviour of three sample models in relation to the signal from a selforganising environment. The behaviour of the three sample models was analyzed. It has a 16-17 readout and a digitisation step - 30 minutes, with total duration of measurements from 12 to 17 days.

The averaging of the intervals between local maxima and minima gives the generalised intervals of the structure of the inhomogeneities (М+, М-).

Fig. 7. Results of the interval definition between the elements of the generalised structure of different types, 'plus' and 'minus' (M+, M-) for some areas (1-12).

Looking at Remote Sensing the Timing of an

structure.

(D+, D-).

and 'minus' has the following character:

Organisation's Point of View and the Anticipation of Today's Problems 233

For the third sample, we see the integral character and the mutual position of the structures, which repeats the second sample at more of the pulse character of the 'minus' signal

This is probably an estimation of the revealed structure of the corresponding dispersion

D1+ D1-

D2+ D2-

1 2 3 4 5 6 7 8 9 10 11 12

Fig. 10. The results of the dispersion definition between the elements of the generalised

1 2 3 4 5 6 7 8 9 10 11 12 13

Fig. 11. Results of the dispersion definition between the elements of the generalised structure of different types, 'plus' and 'minus' (D+, D-) for some areas (1-13).

Change of the dispersion of an interval between the elements of the signal structure 'plus'

structure of different types, 'plus' and 'minus' (D+, D-) for some areas (1-12).

Fig. 8. Results of the interval definition between the elements of the generalised structure of different types, 'plus' and 'minus' (M+, M-) for some areas (1-13).

Fig. 9. Results of the interval definition between the elements of the generalised structure of different types, 'plus' and 'minus' (M+, M-) for some areas (1-17).

The interval size changes between the elements of the generalised structure as 'plus' or 'minus' has a complex character:

For the first sample, the peak growth of the interval sizes for the 'plus' structure (several times) in the third and fifth day is observed. It takes place against a wavy course of the 'minus' structure signal. The character of the change of the 'plus' and 'minus' structures actually coincides with each other in the range of the 9-12 day.

For the second sample, the waviness, falling down character of the dependence, with some subsequent general lifting and the constant prevalence (leadership) of the 'minus' signal structure, is characterised.

M2+ M2-

M3+ M3-

1 2 3 4 5 6 7 8 9 10 11 12 13

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Fig. 9. Results of the interval definition between the elements of the generalised structure of

The interval size changes between the elements of the generalised structure as 'plus' or

For the first sample, the peak growth of the interval sizes for the 'plus' structure (several times) in the third and fifth day is observed. It takes place against a wavy course of the 'minus' structure signal. The character of the change of the 'plus' and 'minus' structures

For the second sample, the waviness, falling down character of the dependence, with some subsequent general lifting and the constant prevalence (leadership) of the 'minus' signal

different types, 'plus' and 'minus' (M+, M-) for some areas (1-13).

different types, 'plus' and 'minus' (M+, M-) for some areas (1-17).

actually coincides with each other in the range of the 9-12 day.

Fig. 8. Results of the interval definition between the elements of the generalised structure of

'minus' has a complex character:

structure, is characterised.

For the third sample, we see the integral character and the mutual position of the structures, which repeats the second sample at more of the pulse character of the 'minus' signal structure.

This is probably an estimation of the revealed structure of the corresponding dispersion (D+, D-).

Fig. 10. The results of the dispersion definition between the elements of the generalised structure of different types, 'plus' and 'minus' (D+, D-) for some areas (1-12).

Fig. 11. Results of the dispersion definition between the elements of the generalised structure of different types, 'plus' and 'minus' (D+, D-) for some areas (1-13).

Change of the dispersion of an interval between the elements of the signal structure 'plus' and 'minus' has the following character:

Looking at Remote Sensing the Timing of an

analysed signal towards its lifting.

0,0

presented above for the regular structure (W1).

0,0 0,5 1,0

presented above for the regular structure (W2).

presented above for the regular structure (W3).

as a uniform structure of a harmonious type.

0,0

0,5

1,0

0,5

1,0

Organisation's Point of View and the Anticipation of Today's Problems 235

It is probably necessary to draw a conclusion - the general excess of the level of probability 0,5 'plus' to for "plus" structures with big emissions W (I) 'plus' against the smooth behaviour of W (I) 'minus' can be a criterion for the displacement of the general course of an

**W1**

1 2 3 4 5 6 7 8 9 10 11 12

**W2**

1 2 3 4 5 6 7 8 9 10 11 12 13

**W3**

1 3 5 7 9 11 13

The connectivity index (S) of the 'plus' and 'minus' structures is equal to zero and corresponds to a case of the behaviour synchronisation of the 'plus' and 'minus' structures,

Fig. 13. The results of the calculation of the regularity index for the three situations

Fig. 14. The results of the calculation of the regularity index for the three situations

Fig. 15. The results of the calculation of the regularity index for the three situations

Fig. 12. Results of the dispersion definition between the elements of the generalised structure of the different types, 'plus' and 'minus' (D+, D-) for some areas (1-17).

For the first sample, the behaviour was similar to the behaviour of the intervals, i.e. the peak growth of the dispersion (instability) of the plus' structure intervals (several times) for the third and fifth day, and against a wavy course the 'minus' structure is characterised.

For the second sample, as well as for intervals, a poorly wavy character of dependence, with a constant prevalence (leadership) 'minus' structure is characterised.

For the third sample, the general character and mutual position of the structures has more pulse character, with emissions in the behaviour structure 'minus' for the second and eleventh day.

For a fuller analysis, additional characteristics have been used:

W – The regularity index; the average probability of the sample regular 'plus', 'minus' structure filling.

S – The connectivity index, the generalised difference of the probabilities of the sample regular 'plus', 'minus' structure filling.

The regularity index (W) of the frequency of the regular structure of the inhomogeneities shows that the probability of filling of the regular sample of the inhomogeneities at a certain interval (I = 1-13) is close to 0.5 only in the case where there is a sufficiently steady structure.

The characteristic tendency - the general course of curve W (I) is a little below the line 0,5. Essentially, the different behaviour of the regularity index (W) for the 'plus' and 'minus' structures is observed.

The W (I) of the 'minus' structure has a wavy character and actually does not reach the values 0,5. The W (I) of the 'plus' of the structure has a peaking characteristic and can reach values essentially more than 0,5 i.e. to fill all the sample.

D3+ D3-

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Fig. 12. Results of the dispersion definition between the elements of the generalised structure of the different types, 'plus' and 'minus' (D+, D-) for some areas (1-17).

third and fifth day, and against a wavy course the 'minus' structure is characterised.

a constant prevalence (leadership) 'minus' structure is characterised.

For a fuller analysis, additional characteristics have been used:

values essentially more than 0,5 i.e. to fill all the sample.

For the first sample, the behaviour was similar to the behaviour of the intervals, i.e. the peak growth of the dispersion (instability) of the plus' structure intervals (several times) for the

For the second sample, as well as for intervals, a poorly wavy character of dependence, with

For the third sample, the general character and mutual position of the structures has more pulse character, with emissions in the behaviour structure 'minus' for the second and

W – The regularity index; the average probability of the sample regular 'plus', 'minus'

S – The connectivity index, the generalised difference of the probabilities of the sample

The regularity index (W) of the frequency of the regular structure of the inhomogeneities shows that the probability of filling of the regular sample of the inhomogeneities at a certain interval (I = 1-13) is close to 0.5 only in the case where there is a sufficiently steady structure. The characteristic tendency - the general course of curve W (I) is a little below the line 0,5. Essentially, the different behaviour of the regularity index (W) for the 'plus' and 'minus'

The W (I) of the 'minus' structure has a wavy character and actually does not reach the values 0,5. The W (I) of the 'plus' of the structure has a peaking characteristic and can reach

eleventh day.

structure filling.

structures is observed.

regular 'plus', 'minus' structure filling.

It is probably necessary to draw a conclusion - the general excess of the level of probability 0,5 'plus' to for "plus" structures with big emissions W (I) 'plus' against the smooth behaviour of W (I) 'minus' can be a criterion for the displacement of the general course of an analysed signal towards its lifting.

Fig. 13. The results of the calculation of the regularity index for the three situations presented above for the regular structure (W1).

Fig. 14. The results of the calculation of the regularity index for the three situations presented above for the regular structure (W2).

Fig. 15. The results of the calculation of the regularity index for the three situations presented above for the regular structure (W3).

The connectivity index (S) of the 'plus' and 'minus' structures is equal to zero and corresponds to a case of the behaviour synchronisation of the 'plus' and 'minus' structures, as a uniform structure of a harmonious type.

Looking at Remote Sensing the Timing of an

leadership of the structure of the 'plus' type.

three samples of a signal, as the above results show.

These estimates allow us to make some significant findings:

'plus' type.

**5. Conclusion 5.1 Measurements** 

or dark laser impulses.

multiple scattering.

performance.

**5.2 Processing** 

Organisation's Point of View and the Anticipation of Today's Problems 237

For first sample, the connectivity index S1 (I) specifies the stable leader-structure of the

For the second sample, the connectivity index S1 (I) specifies the transition of leadership

For the third sample, the of connectivity index S3 (I) specifies the steady growth of the

The conclusion about the displacement of the general course of an analysed signal towards its general growth proves to be true in the presence of the 'plus' of leader-structures in all

1. Increasing the accuracy of the measurement of the scattering signal can be achieved through the use of the described methods of the signal processing, long laser impulses

2. This approach allows more accurate measurement of the scattering signal, by at least an order of magnitude, as well as measurements during the daytime up to distances comparable with the meteorological visibility range (MDV), including the area of

3. The proposed system of remote measurement organisation allows us to solve existing contradictions and provides a specified signal/noise ratio under a wide range of conditions and at different times for remote tracks, and it allows the more accurate linking of the principles of recording equipment with the methodology of interpreting the data. 4. The application of the proposed approach to the principles of the construction of lidar systems allows us to use low-power light sources and, in a large measure, to get rid of

5. This organisation of remote sensing systems allows us to pass from the problem of signal detection with high accuracy to the problem of minimising the distortion of the

6. The system with the probe interval (dark pulse) between impulses (type III) is the greatest prospect and it retains all of the advantages of systems of type II but with more

The results obtained allow for a new approach to the problem of reconstructing the characteristics of the environment based upon remote sensing. It is not correctly solved for a real, heterogeneous environment, largely due to the exclusion of the consideration of

1. "Leadership 'plus' structure" and "Leadership 'minus' structure" specifies, accordingly,

hardware errors caused by shock loads on the receiving system.

received signal, which is caused by instrumental factors.

thermodynamic processes (Polkanov, Y. A. et al., 1991).

the general lifting or falling of the signal.

On the basis of the assumptions made, it is possible to draw the following conclusions:

from the structure of the 'minus' type to the structure of the 'plus' type.

Fig. 16. The results of the calculation of the regularity index for the three situations presented above for the regular structure (W1).

The displacement of the connectivity index (S) in the 'plus' and 'minus' zone specifies on increase in the influence of 'plus' and 'minus' structures with an increase in the independence of their behaviour, rather than each other.

The displacement of the connectivity index (S) in a 'plus' zone can be interpreted as the presence of the leader-structure of the 'plus' type.

The displacement of an index of connectivity (S) in the 'minus' zone can be interpreted as the presence of the leader- structure of the 'minus' type.

Fig. 17. The results of the calculation of the regularity index for the three situations presented above for the regular structure (W2).

Fig. 18. The results of the calculation of the connectivity index for the three situations presented above for the regular structure (W3).

On the basis of the assumptions made, it is possible to draw the following conclusions:

For first sample, the connectivity index S1 (I) specifies the stable leader-structure of the 'plus' type.

For the second sample, the connectivity index S1 (I) specifies the transition of leadership from the structure of the 'minus' type to the structure of the 'plus' type.

For the third sample, the of connectivity index S3 (I) specifies the steady growth of the leadership of the structure of the 'plus' type.

The conclusion about the displacement of the general course of an analysed signal towards its general growth proves to be true in the presence of the 'plus' of leader-structures in all three samples of a signal, as the above results show.
