CN109995427A - A kind of Monte Carlo simulation method of underwater uplink laser communication - Google Patents
A kind of Monte Carlo simulation method of underwater uplink laser communication Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
- H04B10/073—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an out-of-service signal
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/70—Photonic quantum communication
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/80—Optical aspects relating to the use of optical transmission for specific applications, not provided for in groups H04B10/03 - H04B10/70, e.g. optical power feeding or optical transmission through water
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Abstract
The present invention provides a kind of Monte Carlo simulation method of underwater uplink laser communication.The Monte Carlo simulation method of the underwater uplink laser communication, the initial coordinate including determining photon, comprising: the primary quantity for obtaining photon samples the Gauss light source of laser, generates primary light source；Coordinate position next time is calculated according to last photon coordinate position, comprising: the random free step-length for generating photon generates initial scatter angle by Scattering Phase Function, determines random orientations angle, determine the initial transmission direction cosine of photon；According to the different height of photon, scattering whether occurs in next step to photon and judges.The Monte Carlo simulation method of underwater uplink laser communication provided by the invention, simulated photons during transmission, scattering and weight decaying, and then calculate and judge position and the weight of photon equilibrium state, it realizes the situation for accurately simulating subsurface communication, provides important directive significance to improve the quality and stability of subsurface communication.
Description
Technical field
The present invention relates to technical field of communication equipment more particularly to a kind of Monte Carlo simulations of underwater uplink laser communication
Method.
Background technique
Washing laser communication is to utilize sea water transmittance window --- the technology that bluish-green laser is communicated as carrier wave.It is underwater to swash
Optical communication system is as follows: information → compressed encoding → modulation laser → transmitting → reception → filtering → demodulation → decoding → information
Restore.The characteristics of bluish-green laser is can to penetrate cloud layer and seawater, and with electromagnetic wave phase ratio, high directivity, information hiding is good, letter
It is high (reaching thousands of bits per second) to cease transmission rate.It can be used for communication for coordination and communication for command.The former refers to submarine-aircraft, submarine-submarine
Between communicate；The latter refers to that land commander passes through the communication for command between satellite or aircraft and submarine and control communicates.
In order to ensure the stability of subsurface communication needs to simulate subsurface communication, subsurface communication analogy method now
Incomplete to simulate underwater environment when carrying out photonic analogy, the scattering position of photon is unable to get accurate modeling, therefore
In the presence of very big error.
Therefore, it is necessary to which a kind of Monte Carlo simulation method for providing new underwater uplink laser communication solves above-mentioned technology
Problem.
Summary of the invention
The technical problem to be solved by the present invention is to provide a kind of underwater uplink laser communications easy to operate, cleaning effect is good
Monte Carlo simulation method.
In order to solve the above technical problems, the Monte Carlo simulation method packet of underwater uplink laser communication provided by the invention
It includes: determining the initial coordinate of photon, comprising:
The primary quantity of photon is obtained,
The Gauss light source of laser is sampled, primary light source is generated；
Coordinate position next time is calculated according to last photon coordinate position, comprising:
The random free step-length of photon is generated,
Initial scatter angle is generated by Scattering Phase Function, determines random orientations angle,
Determine the initial transmission direction cosine of photon；
According to the different height of photon, scattering whether occurs in next step to photon and judges.
Preferably, described to include: to whether photon next step occurs to scatter to judge
Judge whether photon reaches the water surface,
If so, generating the inclination angle on current photon outgoing sea at random, change the transmission side of photon according to refraction theorem
To decaying to photon energy, carry out size judgement with the thresholding in advance set to photon weight；
If it is not, then judge whether photon reaches receiving plane,
If so, the coordinate position and weight information of current photon on the receiving surface are recorded,
If it is not, decaying to photon energy, size judgement is carried out with the thresholding set in advance to photon weight.
Preferably, the photon energy is decayed as the weight for reducing photon.
Preferably, described to include with the thresholding progress size judgement set in advance to photon weight；
Photon weight is less than the thresholding set in advance in advance, then it is defeated to carry out wheel disc, regenerates photon；
Photon weight then carries out the next step scattering of photon not less than the thresholding set in advance in advance.
Preferably, the calculating formula of the initial coordinate of the photon are as follows:
If light source is located at the origin position of rectangular coordinate system in space, zenith direction is the positive direction of z-axis, the light intensity clothes of light source
From Gaussian Profile, initial scatter angle is determined by light source
Wherein, r0For sample radius,fl=-d0/Θdiv/2, d0For laser beam width,
Θdiv/2For divergence half-angle, azimuth ψ0=2 π ξ, ξ are the random number in 0-1；Therefore, the initial coordinate of photon is
The calculating formula of the initial transmission direction cosines of the photon is
Preferably, the random free step-length for generating photon is calculated by the probability sampling of step-length, specific to wrap
It includes:
Photon advance free step-length probability distribution be
P (l < l')=1-e-μl' (4)
Probability density function is
P (l')=μ e-μl' (5)
Using Monte Carlo method, free step-length is sampled
L=-ln (ξ)/μ (6)
Wherein, ξ is the equally distributed random number in the section 0-1, and μ is the attenuation coefficient of seawater, according to Beer law, by sea
Water absorption coefficient μaWith scattering coefficient μsIt determines, i.e. μ=μa+μs。
Preferably, described that initial scatter angle is generated by Scattering Phase Function, determine that random orientations angle is by angle of scattering and side
The probability sampling of parallactic angle is calculated, and is specifically included:
Use H-G function come its approximate Scattering Phase Function for
Wherein, θ is angle of scattering, and using Monte Carlo method, sampling can be obtained
Wherein, g is asymmetric factor, and ξ is the random number in 0-1；
For azimuth ψ, the basic axial symmetry in photon random scatter track, probability density function is,
Using Monte Carlo method, sampling can be obtained
The π of ψ=2 ξ (10)
Wherein, ξ is the random number in 0-1.
Preferably, the attenuation of the photon energy is calculated by the absorption of photon, is specifically included:
The loss of weight is
After decaying, the Weighted residue of photon is w- Δ w, it is assumed that initial photon weight w0, n times collision after photon power
Weight is wn, then
As it can be seen that exponentially form declines weight photon in transmission process.
Preferably, the calculating formula in the scattering direction of the coordinate position next time includes:
It determines the new direction cosines of photon, is
If the transmission direction of photon and calmness sea/vapor interface normal direction are substantial access to (μz 2> 0.99), that photon
New direction cosines be
Preferably, described to judge whether photon reaches the water surface or receiving plane is catadioptric by calculating photon sea/vapor interface
Representation by arrows specifically includes:
Defining photon and reaching sea/vapor interface distance along transmission direction from current location is reduction step-length s
In formula (15), zboundaryFor sea/vapor interface Z coordinate, z is that photon is reached before sea/vapor interface and scattered next time
The Z coordinate for the scattering point that will be reflected, works as μzWhen=0, photon is parallel to sea/vapor interface movement, and photon will not touch side
Boundary is omitted；
When the free step-length of photon is less than reduction step-length (l < s), photon does not reach sea/vapor interface, does not occur catadioptric
It penetrates, continues to transmit in the seawater, when the free step-length of photon is more than or equal to reduction step-length (l >=s), photon reaches sea/gas circle
Catadioptric, incidence angle α occur for face, photoni, refraction angle αt, incidence angle by current scattering point direction cosines and sea/gas circle
The normal direction cosine in face codetermines；
Wave at different wind speeds pitch angle β experience normalization probability density formula be
Root mean square σ=(0.003+0.00512 υ) in formula (16)1/2, υ is wind speed, it can thus be concluded that the value of pitch angle β；IfFor the normal direction of wave, direction cosines nx, ny, nz, then
Wherein α is azimuth, is uniformly distributed in the section [0,2 π], i.e. the π of α=2 ξ, ξ are the random number in 0-1；
The normal direction of sea/vapor interface normal planeWith incident directionWith sea/
The normal direction of vapor interfaceMeet
It can obtain
If refractive direction isu′x, u 'y, uz' be refractive direction direction cosines；Refractive direction with enter
The normal direction for penetrating plane meetsThen
mxu′x+myu′y+mzu′z=0 (20)
Refraction angle αtN is provided by the snell law of refractionseasinαi=nairsinαt, andI.e.
nxu′x+nyu′y+nzu′z=cos αt (21)
And
u′x+u′y+u′z=1 (22)
Joint type (20), formula (21), formula (22), solve
Wherein
Refraction angle direction cosines u 'x, u 'y, u 'zSymbol accept or reject, it is smaller according to incidence angle and refraction angle angle absolute value
The correct refraction angle direction cosines of correspondence；
Reflectivity R (α of the photon when dielectric boundaries reflecti) provided by the derivative formula of Fresnel
Compared with the relevant technologies, the Monte Carlo simulation method of underwater uplink laser communication provided by the invention has such as
It is lower the utility model has the advantages that
The present invention provides a kind of Monte Carlo simulation method of underwater uplink laser communication, using monte carlo method, mould
Quasi- photon during transmission, scattering and the decaying of weight, and then calculate and judge position and the weight of photon equilibrium state,
It realizes the situation for accurately simulating subsurface communication, provides important guidance meaning to improve the quality and stability of subsurface communication
Justice.
Detailed description of the invention
Fig. 1 is the flow diagram of the Monte Carlo simulation method of underwater uplink laser communication provided by the invention；
Fig. 2 is the flow chart of integrated operation of the invention.
Specific embodiment
The invention will be further described with embodiment with reference to the accompanying drawing.
Fig. 1 is the flow diagram of the Monte Carlo simulation method of underwater uplink laser communication provided by the invention；Such as Fig. 1
Shown, the Monte Carlo simulation method of underwater uplink laser communication includes:
Determine the initial coordinate of photon, comprising:
The primary quantity of photon is obtained,
The Gauss light source of laser is sampled, primary light source is generated；
Coordinate position next time is calculated according to last photon coordinate position, comprising:
The random free step-length of photon is generated,
Initial scatter angle is generated by Scattering Phase Function, determines random orientations angle,
Determine the initial transmission direction cosine of photon；
According to the different height of photon, scattering whether occurs in next step to photon and judges.
Wherein, described to include: to whether photon next step occurs to scatter to judge
Judge whether photon reaches the water surface,
If so, generating the inclination angle on current photon outgoing sea at random, change the transmission side of photon according to refraction theorem
To decaying to photon energy, carry out size judgement with the thresholding in advance set to photon weight；
If it is not, then judge whether photon reaches receiving plane,
If so, the coordinate position and weight information of current photon on the receiving surface are recorded,
If it is not, decaying to photon energy, size judgement is carried out with the thresholding set in advance to photon weight.
Specifically, firstly, obtaining the primary quantity of photon, being sampled to the Gauss light source of laser in simulation process, generate
Initial photon determines the initial coordinate of photon；Secondly, generating random free step-length, initial scatter angle is generated by Scattering Phase Function,
Random orientations angle is generated, the initial transmission direction cosine of photon is determined, photon next time is calculated according to last coordinate position
Coordinate position；Finally, whether the height different according to photon, occur scattering in next step to photon and judge.
In scattering process, whether scattering will reach the water surface to photon and judge each time, if reached, at random
The inclination angle for generating current photon outgoing sea, changes the transmission direction of photon according to refraction theorem, declines to photon energy
Subtract the weight for reducing photon.If photon comes into atmosphere, judge whether photon reaches receiving plane, if reached, note
The coordinate position and weight information of current photon on the receiving surface are recorded, if not reaching, decay photon weight, is dissipated next time
It penetrates.Photon, if photon weight is less than a certain thresholding being previously set, carries out wheel disc to it after by Multiple Scattering
Gambling gives the regenerated chance of photon, otherwise terminates the transmission of this photon, carry out the transmission of next photon, until all photons
It is transmitted, analysis comparison is finally carried out according to statistical result.
Specifically, the calculating formula of the initial coordinate of the photon are as follows:
If light source is located at the origin position of rectangular coordinate system in space, zenith direction is the positive direction of z-axis, the light intensity clothes of light source
From Gaussian Profile, initial scatter angle is determined by light source
Wherein, r0For sample radius,fl=-d0/Θdiv/2, d0For laser beam width,
Θdiv/2For divergence half-angle, azimuth ψ0=2 π ξ, ξ be in 0-1 random number (in text following ξ be all by computer every time again
It generates).Therefore, the initial coordinate of photon is
The initial transmission direction cosines of photon are
Specifically, the random free step-length for generating photon is calculated by the probability sampling of step-length, comprising: light
Free step-length between sub- double scattering is that the probability for whether being scattered or being absorbed by it determines, the free step-length that photon is advanced is general
Rate is distributed as
P (l < l')=1-e-μl' (4)
Probability density function is
P (l')=μ e-μl' (5)
Using Monte Carlo method, free step-length is sampled
L=-ln (ξ)/μ (6)
Wherein, ξ is the equally distributed random number in the section 0-1, and μ is the attenuation coefficient of seawater, according to Beer law, by sea
Water absorption coefficient μaWith scattering coefficient μsIt determines, i.e. μ=μa+μs。
Specifically, described generate initial scatter angle by Scattering Phase Function, determine that random orientations angle is by angle of scattering and side
The probability sampling of parallactic angle is calculated, and photon transmits in the seawater, and the suspended particles such as extra large impurities in water cause photon to scatter,
And mainly based on Mie scattering, use H-G function come its approximate Scattering Phase Function for
Wherein, θ is angle of scattering, and using Monte Carlo method, sampling can be obtained[8]
Wherein, g is asymmetric factor, and ξ is the random number in 0-1.
For azimuth ψ, the basic axial symmetry in photon random scatter track, probability density function is
Using Monte Carlo method, sampling can be obtained
The π of ψ=2 ξ (10)
Wherein, ξ is the random number in 0-1.
Specifically, the attenuation of the photon energy is calculated by the absorption of photon,
Photon collides in scattering process with all kinds of impurity in seawater, causes the weight of photon to decay, photon is only
It takes Weighted residue to be scattered next time, the loss of weight is
After decaying, the Weighted residue of photon is w- Δ w, it is assumed that initial photon weight w0, n times collision after photon power
Weight is wn [9], then
As it can be seen that exponentially form declines weight photon in transmission process.
During transmission, each free step-length is accompanied by decaying to photon, and a part of weight is absorbed, and leads to photon
Weight is reduced, and another part weight follows photon equilibrium state, continues to transmit.After photon collision, according to the freedom scattered next time
Step-length, angle of scattering, deflection can determine the new direction cosines of photon, be
If the transmission direction of photon and calmness sea/vapor interface normal direction are substantial access to (μz 2> 0.99), that photon
New direction cosines be
Specifically, described judge whether photon reaches the water surface or receiving plane is catadioptric by calculating photon sea/vapor interface
Representation by arrows,
When photon reaches sea/vapor interface, partial photonic reflects back into seawater, and partial photonic is reflected via sea/vapor interface
Into in atmosphere.Here, defining photon and reaching sea/vapor interface distance along transmission direction from current location is reduction step-length s
In formula (15), zboundaryFor sea/vapor interface Z coordinate, z is that photon is reached before sea/vapor interface and scattered next time
The Z coordinate for the scattering point that will be reflected, works as μzWhen=0, photon is parallel to sea/vapor interface movement, and photon will not touch side
Boundary is omitted.
When the free step-length of photon is less than reduction step-length (l < s), photon does not reach sea/vapor interface, does not occur catadioptric
It penetrates, continues to transmit in the seawater, when the free step-length of photon is more than or equal to reduction step-length (l >=s), photon reaches sea/gas circle
Catadioptric, incidence angle α occur for face, photoni, refraction angle αt, incidence angle by current scattering point direction cosines and sea/gas circle
The normal direction cosine in face codetermines.
Under the influence of sea wind, sea meeting random fluctuation, the normal of sea point tangent plane equally has randomness, Cox etc.
People summarizes certain rule, give wave at different wind speeds pitch angle β experience normalization probability density formula be
Root mean square σ=(0.003+0.00512 υ) in formula (16)1/2, υ is wind speed, it can thus be concluded that the value of pitch angle β.IfFor the normal direction of wave, direction cosines nx, ny, nz, then
Wherein α is azimuth, is uniformly distributed in the section [0,2 π], i.e. the π of α=2 ξ, ξ are the random number in 0-1.
The normal direction of sea/vapor interface normal planeWith incident directionWith sea/
The normal direction of vapor interfaceMeet
It can obtain
If refractive direction isu′x, u 'y, u 'zFor the direction cosines of refractive direction.Refractive direction with enter
The normal direction for penetrating plane meetsThen
mxu′x+myu′y+mzu′z=0 (20)
Refraction angle αtN is provided by the snell law of refractionseasinαi=nairsinαt, andI.e.
nxu′x+nyu′y+nzu′z=cos αt (21)
And
u′x+u′y+u′z=1 (22)
Joint type (20), formula (21), formula (22) solve
Wherein
Refraction angle direction cosines u 'x, u 'y, u 'zSymbol accept or reject, it is smaller according to incidence angle and refraction angle angle absolute value
The correct refraction angle direction cosines of correspondence.
Reflectivity R (α of the photon when dielectric boundaries reflecti) provided by the derivative formula of Fresnel
It requires supplementation with, the above calculating formula, the identical meaning of identical symbology.
It should be noted that photon is during transmission, the decaying for being all accompanied by weight is scattered each time, and photon dissipates
It is more to penetrate number, weight decaying it is more serious, due to the free step-length scattered every time be all it is random, partial photonic may dissipate
Number is penetrated much larger than average scattering number, causes weight too low, if weight is lower than predetermined threshold value wthreshold, illustratively,
The threshold value wthresholdIt is 0.0001, adds up having little significance for photon weight at this time, the transmission process of the photon should be terminated,
However the transmission for directly terminating the photon will lead to simulation result there are precision problem, the method for " roulette " in the present invention, with
Certain probability regains weight by photon, i.e., is each on the verge of the photon of the end of transmission, this all with the chance of primary recycling
Method is statistically unbiased, is a kind of mode that termination photon transmission is more reasonable.
Illustratively, Fig. 2 is the flow chart of integrated operation of the invention；
In simulation process, firstly, determining the initial coordinate of photon, i.e., by obtaining the primary quantity of photon, to the height of laser
This light source is sampled, and initial photon is generated；Secondly, generating random free step-length, initial scatter angle is generated by Scattering Phase Function,
Random orientations angle is generated, the initial transmission direction cosine of photon is determined, photon next time is calculated according to last coordinate position
Coordinate position；Finally, whether the height different according to photon, occur scattering in next step to photon and judge.
When judging, judge first whether photon reaches the water surface, if reached, generates current photon at random and go out
The inclination angle for penetrating sea changes the transmission direction of photon according to refraction theorem, is decayed to photon energy and reduces photon
Weight.If not reaching the water surface, photon comes into atmosphere, then judges whether photon reaches receiving plane, if reached, note
The coordinate position and weight information of current photon on the receiving surface are recorded, if not reaching, decay photon weight, is dissipated next time
It penetrates.Photon is after by Multiple Scattering, illustratively, described if photon weight is less than a certain thresholding being previously set
Threshold value wthresholdIt is 0.0001, when photon weight is less than 0.0001, roulette is carried out to it, gives the regenerated chance of photon,
Otherwise terminate the transmission of this photon, carry out the transmission of next photon, until all photon transmissions are completed, finally according to statistics
As a result analysis comparison is carried out.
The above description is only an embodiment of the present invention, is not intended to limit the scope of the invention, all to utilize this hair
Equivalent structure or equivalent flow shift made by bright specification and accompanying drawing content is applied directly or indirectly in other relevant skills
Art field, is included within the scope of the present invention.
Claims (10)
1. a kind of Monte Carlo simulation method of underwater uplink laser communication, which is characterized in that the emulation mode includes:
Determine the initial coordinate of photon, comprising:
The primary quantity of photon is obtained,
The Gauss light source of laser is sampled, primary light source is generated；
Coordinate position next time is calculated according to last photon coordinate position, comprising:
The random free step-length of photon is generated,
Initial scatter angle is generated by Scattering Phase Function, determines random orientations angle,
Determine the initial transmission direction cosine of photon；
According to the different height of photon, scattering whether occurs in next step to photon and judges.
2. the Monte Carlo simulation method of underwater uplink laser communication according to claim 1, which is characterized in that described right
Whether photon occurs to scatter to judge in next step
Judge whether photon reaches the water surface,
If so, generating the inclination angle on current photon outgoing sea at random, change the transmission direction of photon according to refraction theorem, it is right
Photon energy decays, and carries out size judgement with the thresholding set in advance to photon weight；
If it is not, then judge whether photon reaches receiving plane,
If so, the coordinate position and weight information of current photon on the receiving surface are recorded,
If it is not, decaying to photon energy, size judgement is carried out with the thresholding set in advance to photon weight.
3. the Monte Carlo simulation method of underwater uplink laser communication according to claim 2, which is characterized in that the light
Sub- energy is decayed as the weight for reducing photon.
4. the Monte Carlo simulation method of underwater uplink laser communication according to claim 2, which is characterized in that described right
Photon weight carries out size judgement with the thresholding set in advance；
Photon weight is less than the thresholding set in advance in advance, then it is defeated to carry out wheel disc, regenerates photon；
Photon weight then carries out the next step scattering of photon not less than the thresholding set in advance in advance.
5. the Monte Carlo simulation method of underwater uplink laser communication according to claim 4, which is characterized in that the light
The calculating formula of the initial coordinate of son are as follows:
If light source is located at the origin position of rectangular coordinate system in space, zenith direction is the positive direction of z-axis, and the light intensity of light source is obeyed high
This distribution, initial scatter angle is determined by light source
Wherein, r0For sample radius,fl=-d0/Θdiv/2, d0For laser beam width, Θdiv/2For hair
Dissipate half-angle, azimuth ψ0=2 π ξ, ξ are the random number in 0-1；Therefore, the initial coordinate of photon is
The calculating formula of the initial transmission direction cosines of the photon is
6. the Monte Carlo simulation method of underwater uplink laser communication according to claim 5, which is characterized in that the life
It at the random free step-length of photon is calculated by the probability sampling of step-length, specifically included:
Photon advance free step-length probability distribution be
P (l < l')=1-e-μl' (4)
Probability density function is
P (l')=μ e-μl' (5)
Using Monte Carlo method, free step-length is sampled
L=-ln (ξ)/μ (6)
Wherein, ξ is the equally distributed random number in the section 0-1, and μ is that the attenuation coefficient of seawater is inhaled according to Beer law by seawater
Receive coefficient μaWith scattering coefficient μsIt determines, i.e. μ=μa+μs。
7. the Monte Carlo simulation method of underwater uplink laser communication according to claim 6, which is characterized in that it is described by
Scattering Phase Function generates initial scatter angle, determines that random orientations angle is counted by angle of scattering and azimuthal probability sampling
It calculates, specifically includes:
Use H-G function come its approximate Scattering Phase Function for
Wherein, θ is angle of scattering, and using Monte Carlo method, sampling can be obtained
Wherein, g is asymmetric factor, and ξ is the random number in 0-1；
For azimuth ψ, the basic axial symmetry in photon random scatter track, probability density function is,
Using Monte Carlo method, sampling can be obtained
The π of ψ=2 ξ (10)
Wherein, ξ is the random number in 0-1.
8. the Monte Carlo simulation method of underwater uplink laser communication according to claim 7, which is characterized in that the light
The attenuation of sub- energy is calculated by the absorption of photon, is specifically included:
The loss of weight is
After decaying, the Weighted residue of photon is w- Δ w, it is assumed that initial photon weight w0, n times collision after photon weight be
wn, then
As it can be seen that exponentially form declines weight photon in transmission process.
9. the Monte Carlo simulation method of underwater uplink laser communication according to claim 8, which is characterized in that under described
The calculating formula in the scattering direction of coordinate position includes:
It determines the new direction cosines of photon, is
If the transmission direction of photon and calmness sea/vapor interface normal direction are substantial access to (μz 2> 0.99), that photon it is new
Direction cosines be
10. the Monte Carlo simulation method of underwater uplink laser communication according to claim 9, which is characterized in that described
Judge whether photon reaches the water surface or receiving plane is specifically included by the calculating catadioptric representation by arrows of photon sea/vapor interface:
Defining photon and reaching sea/vapor interface distance along transmission direction from current location is reduction step-length s
In formula (15), zboundaryFor sea/vapor interface Z coordinate, z is that photon reaches before sea/vapor interface and scattering will next time
The Z coordinate of the scattering point reflected, works as μzWhen=0, photon is parallel to sea/vapor interface movement, and photon will not touch boundary, give
To ignore；
When the free step-length of photon is less than reduction step-length (l < s), photon does not reach sea/vapor interface, and catadioptric does not occur,
Continue to transmit in the seawater, when the free step-length of photon is more than or equal to reduction step-length (l >=s), photon reaches sea/vapor interface,
Catadioptric, incidence angle α occur for photoni, refraction angle αt, incidence angle by current scattering point direction cosines and sea/vapor interface
Normal direction cosine codetermines；
Wave at different wind speeds pitch angle β experience normalization probability density formula be
Root mean square σ=(0.003+0.00512 υ) in formula (16)1/2, υ is wind speed, it can thus be concluded that the value of pitch angle β；IfFor the normal direction of wave, direction cosines nx, ny, nz, then
Wherein α is azimuth, is uniformly distributed in the section [0,2 π], i.e. the π of α=2 ξ, ξ are the random number in 0-1；
The normal direction of sea/vapor interface normal planeWith incident directionWith sea/vapor interface
Normal directionMeet
It can obtain
If refractive direction isu′x, u 'y, u 'zFor the direction cosines of refractive direction；Refractive direction and incidence are flat
The normal direction in face meetsThen
mxu′x+myu′y+mzu′z=0 (20)
Refraction angle αtN is provided by the snell law of refractionseasinαi=nairsinαt, andI.e.
nxu′x+nyu′y+nzu′z=cos αt (21)
And
u′x+u′y+u′z=1 (22)
Joint type (20), formula (21), formula (22), solve
Wherein
Refraction angle direction cosines u 'x, u 'y, u 'zSymbol accept or reject, it is lesser right according to incidence angle and refraction angle angle absolute value
Answer correct refraction angle direction cosines；
Reflectivity R (α of the photon when dielectric boundaries reflecti) provided by the derivative formula of Fresnel
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| CN110661568A (en) * | 2019-10-28 | 2020-01-07 | 桂林电子科技大学 | Method for calculating 3dB intensity light spot radius of underwater arrival laser signal |
| CN110912617A (en) * | 2019-11-05 | 2020-03-24 | 中南大学 | Increase and decrease photon system for improving underwater continuous variable quantum key distribution and implementation method thereof |
| CN111555822A (en) * | 2020-04-28 | 2020-08-18 | 西安邮电大学 | Phase screen-based underwater wireless light transmission Monte Carlo simulation method |
| CN112235044A (en) * | 2020-09-21 | 2021-01-15 | 西安理工大学 | Channel modeling method of underwater laser communication system |
| CN112636821A (en) * | 2020-12-18 | 2021-04-09 | 南京先进激光技术研究院 | Underwater wireless optical communication optical channel simulation method and simulation system |
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| CN110661568A (en) * | 2019-10-28 | 2020-01-07 | 桂林电子科技大学 | Method for calculating 3dB intensity light spot radius of underwater arrival laser signal |
| CN110661568B (en) * | 2019-10-28 | 2022-04-15 | 桂林电子科技大学 | Method for calculating 3dB intensity light spot radius of underwater arrival laser signal |
| CN110912617A (en) * | 2019-11-05 | 2020-03-24 | 中南大学 | Increase and decrease photon system for improving underwater continuous variable quantum key distribution and implementation method thereof |
| CN110912617B (en) * | 2019-11-05 | 2020-10-02 | 中南大学 | Increase and decrease photon system for improving underwater continuous variable quantum key distribution and implementation method thereof |
| CN111555822A (en) * | 2020-04-28 | 2020-08-18 | 西安邮电大学 | Phase screen-based underwater wireless light transmission Monte Carlo simulation method |
| CN111555822B (en) * | 2020-04-28 | 2021-08-20 | 西安邮电大学 | Phase screen-based underwater wireless light transmission Monte Carlo simulation method |
| CN112235044B (en) * | 2020-09-21 | 2021-12-07 | 西安理工大学 | Channel modeling method of underwater laser communication system |
| CN112235044A (en) * | 2020-09-21 | 2021-01-15 | 西安理工大学 | Channel modeling method of underwater laser communication system |
| CN112636821A (en) * | 2020-12-18 | 2021-04-09 | 南京先进激光技术研究院 | Underwater wireless optical communication optical channel simulation method and simulation system |
| CN113078957B (en) * | 2021-03-16 | 2022-06-21 | 河海大学 | UWOC system channel characteristic MCNS method based on space coordinate transformation technology |
| CN113078957A (en) * | 2021-03-16 | 2021-07-06 | 河海大学 | UWOC system channel characteristic MCNS method based on space coordinate transformation technology |
| CN113297643B (en) * | 2021-04-14 | 2023-02-03 | 西安理工大学 | Method for calculating light spot area in underwater blue-green laser communication |
| CN113297643A (en) * | 2021-04-14 | 2021-08-24 | 西安理工大学 | Method for calculating light spot area in underwater blue-green laser communication |
| CN113361080A (en) * | 2021-05-20 | 2021-09-07 | 厦门大学 | Multilayer water photon transmission semi-analytic Monte Carlo simulation method based on GPU |
| CN113361080B (en) * | 2021-05-20 | 2022-05-17 | 厦门大学 | Multilayer water photon transmission semi-analytic Monte Carlo simulation method based on GPU |
| CN113626997A (en) * | 2021-07-23 | 2021-11-09 | 北京理工大学 | Pulse laser transmission characteristic simulation method in dust raising environment |
| CN113626997B (en) * | 2021-07-23 | 2024-04-12 | 北京理工大学 | Pulse laser transmission characteristic simulation method in dust environment |
| CN113740873A (en) * | 2021-08-31 | 2021-12-03 | 自然资源部第二海洋研究所 | Gaussian convolution-based marine laser radar rapid simulation method |
| CN113740873B (en) * | 2021-08-31 | 2024-05-28 | 自然资源部第二海洋研究所 | Ocean laser radar rapid simulation method based on Gaussian convolution |
| CN116644621A (en) * | 2023-07-27 | 2023-08-25 | 始终(无锡)医疗科技有限公司 | Full-spectrum backward scattering diffuse reflectance simulation method |
| CN116644621B (en) * | 2023-07-27 | 2023-10-20 | 始终(无锡)医疗科技有限公司 | Full-spectrum backward scattering diffuse reflectance simulation method |
| CN117152401A (en) * | 2023-09-05 | 2023-12-01 | 南通海沐海洋工程装备有限公司 | Acquisition method of underwater visual image data set for machine learning task |
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Application publication date: 20190709 |