CN116719049A - Method and system for estimating noise of ocean area of satellite-borne single-photon laser radar - Google Patents
Method and system for estimating noise of ocean area of satellite-borne single-photon laser radar Download PDFInfo
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Abstract
The invention provides a method and a system for estimating ocean region noise of a satellite-borne single-photon laser radar, wherein the method comprises the following steps: step 1, calculating the Rayleigh scattering noise f of the atmosphere r The method comprises the steps of carrying out a first treatment on the surface of the Step 2, calculating the scattering noise f of the atmospheric aerosol a The method comprises the steps of carrying out a first treatment on the surface of the Step 3, calculating water surface reflection noise; step 4, calculating water reflection noise below the water surface; and 5, calculating the total noise of the laser radar based on the steps 1-4. The method comprehensively considers the contributions of the noise of the Rayleigh scattering, the aerosol scattering, the white foam reflection on the water surface, the specular reflection and the water body reflection, accurately models the noise, decomposes the atmosphere into two parts of Rayleigh scattering and aerosol scattering in detail, and puts forward a corresponding noise formula, thereby estimating the noise size of a laser radar system or a transmitted satellite, greatly improving the precision, scientifically and reliably assisting the laser radarThe design optimization of system parameters is achieved, and the method has important significance for analyzing the influence of the system parameters and environmental parameters on the noise and the design of the subsequent single-photon laser radar satellite.
Description
Technical Field
The invention belongs to the technical field of laser remote sensing, and particularly relates to a satellite-borne single-photon laser radar ocean region noise estimation method and system.
Background
The satellite ocean remote sensing technology occupies a very important position in an ocean observation system and plays a very important role in the fields of global ocean carbon circulation, sea level rising, ocean wave observation and the like. The satellite-borne single-photon laser radar has a remarkable application prospect in the aspects of ocean exploration, underwater sounding, ocean subsurface optical parameter exploration and the like according to high sensitivity, high resolution and high measurement precision. The ICESat-2 (Ice, cloud, and land Elevation Satellite-2) satellite carries the first on-board single-photon lidar in the world, ATLAS (Advanced Topographic Laser Altimeter System), capable of responding to return signals of weak photon magnitude.
Solar radiation is the most important noise source in the daytime of a satellite-borne single-photon laser radar system, and photons of solar radiation reflected back by atmosphere, water surface, water body and the like can be received and recorded by a laser radar receiving system to form noise photon point cloud. An accurate noise estimation model is of great significance to further application of laser radar noise data (such as application of land and water classification, sea ice classification and the like) and system design and optimization of future satellite-borne laser radars. The noise estimation of the marine area of the satellite-borne single-photon laser radar can be realized by accurately modeling the backward reflection noise items of the atmosphere, the water surface and the water body and inputting the parameters of the laser radar system and the environmental parameters.
Degnan proposed a satellite-borne single-photon lidar land noise model (simply referred to as the Degnan model) that reduced the atmosphere to all co-scattered and non-absorbed gas particles, and deduced the atmospheric back-scattered noise. And the surface of the earth is approximated as a lambertian body in the Degnan model, and the main reflection characteristic of the water surface is specular reflection, which is quite different from the reflection of the lambertian body. The noise model published at present is mostly based on the Degnan model, only the magnitude of noise can be estimated approximately, and the noise model has larger error (more than 50%).
Disclosure of Invention
The invention aims to solve the problems, and aims to provide a method and a system for estimating the noise of a marine area of a satellite-borne single-photon laser radar, which can greatly improve the noise estimation precision.
In order to achieve the above object, the present invention adopts the following scheme:
< method >
As shown in fig. 1, the invention provides a method for estimating ocean area noise of a satellite-borne single-photon laser radar, which comprises the following steps:
step 1, calculating the Rayleigh scattering noise f of the atmosphere r ：
Wherein F is the calibration coefficient of the satellite-borne laser radar system; η is the overall receive system efficiency including the optical system receive efficiency and the detector quantum efficiency; n (N) λ Is the irradiance of the sun outside the atmosphere; θ r Is the system receiving half field angle; a is that r The caliber of the telescope is; hv is the single photon energy; p (P) r Is a Rayleigh scattering phase function; angle theta s And phi s Zenith and azimuth angles, respectively, of the vector from the sea surface measurement point to the sun; r (theta) is the Fresnel reflectivity of the water-air interface when the incident angle is theta; τ r Is the rayleigh optical thickness; Δλ is the filter bandwidth; alpha is the scattering angle; θ v And phi v The space base angle and the azimuth angle from the ICESat-2 receiving telescope to the sea surface measuring point are respectively; θ ± ＝±θ s ，θ + ＝+θ s ，θ ﹣ ＝﹣θ s ；
Step 2, calculating the scattering noise f of the atmospheric aerosol a ：
Wherein w is a Is the single scattering ratio of aerosol, τ a Is the optical thickness of aerosol, a, g 1 、g 2 Are constants determined according to historical data;
step 3, calculating water surface reflection noise;
step 4, calculating water reflection noise below the water surface;
and 5, calculating the total noise of the laser radar based on the steps 1-4.
Preferably, in the method for estimating the noise of the ocean area of the satellite-borne single-photon laser radar provided by the invention, in step 3, the noise f is reflected on the water surface surf Including background light noise f generated by white foam reflection on water surface s,foam Background light noise f generated by specular reflection on water surface s,specular The method comprises the steps of carrying out a first treatment on the surface of the The background light noise generated by the specular reflection of the water surface is as follows:
wherein ρ is s Is the Fresnel reflectivity of the water surface; t (T) a Is the direct atmospheric transmittance in the direction of the zenith; s is(s) 2 Is the root mean square slope of the sea surface.
Preferably, in the method for estimating the ocean area noise of the satellite-borne single-photon laser radar provided by the invention, in step 2, a=0.983 and g 1 ＝0.82、g 2 -0.55; in step 3, s 2 ＝0.003+0.00512U 10 ，U 10 Is the wind speed at 10 meters above the sea surface.
Preferably, in the method for estimating the noise of the ocean area of the satellite-borne single-photon laser radar provided by the invention, in step 4, the noise f is reflected by the water body w ：
Wherein R is rs Is apparent optical coefficient remote sensing reflectivity.
Preferably, in the method for estimating the noise of the ocean area of the satellite-borne single-photon laser radar provided by the invention, in step 5, the total noise f of the laser radar all =atmospheric rayleigh scattering noise f r +atmospheric aerosol scattering noise f a +Water surface reflection noise f surf +Water reflection noise term f w +detector dark count noise f d 。
< System >
Furthermore, the invention also provides a noise estimation system of the satellite-borne single-photon laser radar capable of automatically realizing the method, which comprises the following steps:
f r a calculation unit for calculating the Rayleigh scattering noise f of the atmosphere r ：
Wherein F is the calibration coefficient of the satellite-borne laser radar system; η is the overall receive system efficiency including the optical system receive efficiency and the detector quantum efficiency; n (N) λ Is the irradiance of the sun outside the atmosphere; θ r Is the system receiving half field angle; a is that r The caliber of the telescope is; hv is the single photon energy; p (P) r Is a Rayleigh scattering phase function; angle theta s And phi s Zenith and azimuth angles, respectively, of the vector from the sea surface measurement point to the sun; r (theta) is the Fresnel reflectivity of the water-air interface when the incident angle is theta; τ r Is the rayleigh optical thickness; Δλ is the filter bandwidth; alpha is the scattering angle; θ v And phi v The space base angle and the azimuth angle from the ICESat-2 receiving telescope to the sea surface measuring point are respectively; θ ± ＝±θ s ，θ + ＝+θ s ，θ ﹣ ＝﹣θ s ；
f a A calculation unit for calculating the atmospheric aerosol scattering noise f a ：
Wherein w is a Is the single scattering ratio of aerosol, τ a Is the optical thickness of aerosol, a, g 1 、g 2 Are constants determined according to historical data;
total noise calculation unit based on f r 、f a Calculating total noise f of laser radar all ；
Control part, and f r Calculation part f a The computing parts are all in communication connection and control the operation of the computing parts.
The noise estimation system of the satellite-borne single-photon laser radar provided by the invention can further comprise: a laser radar parameter optimizing part which is communicated with the control part and is used for controlling the laser radar according to f r 、f a And total noise f of laser radar all And optimizing and configuring laser radar system parameters.
The noise estimation system of the satellite-borne single-photon laser radar provided by the invention can further comprise: f (f) surf A calculation unit for calculating the water surface reflection noise f surf The method comprises the steps of carrying out a first treatment on the surface of the And f w A calculation unit for calculating the reflection noise f of the water body below the water surface w The method comprises the steps of carrying out a first treatment on the surface of the The noise estimation system of the satellite-borne single-photon laser radar is used for noise estimation in the ocean area; the total noise calculation unit is based on f r 、f a 、f surf 、f w Calculating total noise f of laser radar all The method comprises the steps of carrying out a first treatment on the surface of the Control part and f r Calculation part f a Calculation part f surf Calculation part f w The computing parts are all in communication connection and control the operation of the computing parts; the laser radar parameter optimization part is based on f r 、f a 、f surf 、f w And total noise f of laser radar all And optimizing and configuring laser radar system parameters.
The noise estimation system of the satellite-borne single-photon laser radar provided by the invention can further comprise: and the input display part is in communication connection with the control part and is used for enabling a user to input an operation instruction and correspondingly display the operation instruction.
Preferably, the noise estimation system of the satellite-borne single-photon laser radar provided by the invention is characterized in that surf In the calculating part, the water surface reflection noise f surf Including back generated by reflection of white foam on water surfaceScenic noise f s,foam Background light noise f generated by specular reflection on water surface s,specular The method comprises the steps of carrying out a first treatment on the surface of the The background light noise generated by the specular reflection of the water surface is as follows:
wherein ρ is s Is the Fresnel reflectivity of the water surface; t (T) a Is the direct atmospheric transmittance in the direction of the zenith; s is(s) 2 Is the root mean square slope of the sea surface.
Effects and effects of the invention
According to the method disclosed by the invention, the contributions of the Rayleigh scattering, the aerosol scattering, the white foam reflection on the water surface, the specular reflection and the reflection noise of the water body below the water surface are comprehensively considered, the noise is accurately modeled, the atmosphere is decomposed into the Rayleigh scattering and the aerosol scattering in detail, a corresponding noise formula is provided, the specular reflection characteristic of the ocean surface is accurately modeled, the noise size of a laser radar system or a transmitted satellite is further estimated, the precision can be greatly improved, the design optimization of the parameters of the laser radar system is scientifically and reliably assisted, and the method has important significance in analyzing the influence of the parameters of the system and the environmental parameters on the noise size and the design of a subsequent single-photon laser radar satellite. The system can rapidly and accurately estimate the noise size of the satellite-borne single-photon laser radar through the input of the satellite-borne single-photon laser radar parameters and various environmental parameters, and is used for the optimization design of the satellite-borne laser radar ocean laser radar. Furthermore, for noise evaluation of other areas of the satellite-borne single-photon laser radar, the Rayleigh scattering and aerosol scattering calculation method can still be well applied.
Drawings
FIG. 1 is a flow chart of a method for estimating ocean area noise of a satellite-borne single-photon laser radar according to the invention;
fig. 2 is a diagram of comparing actual noise with theoretical noise of an ICESat-2 satellite-mounted single-photon lidar according to an embodiment of the present invention, in which a black solid line represents actual noise actually observed by an ICESat-2 system, and a black dotted line represents an ICESat-2 theoretical noise rate estimated according to the method of the present invention.
Detailed Description
The following describes in detail a specific embodiment of a method and a system for estimating ocean area noise of a satellite-borne single-photon laser radar according to the present invention with reference to the accompanying drawings.
Example 1
In this embodiment, the system parameters and the environmental parameters of the global first satellite-borne single-photon laser radar ATLAS (Advance Topographic Laser Altimeter System) are taken as examples by ICESat-2 (Ice, cloud, and land Elevation Satellite-2). The ATLAS system emits a 6 beam 532nm wavelength green laser to the earth at a repetition rate of 10kHz, where the ATL03 product provides point cloud data (including specific time, latitude and longitude, solar azimuth and altitude) for orbital flight and statistical noise rates during actual operation.
The sample specifically selects the track ICESat-2 ATL03 data acquired by the ICESat-2 spaceborne laser radar on 21 st of 2020, the track latitude span is 9.5 degrees to 22.5 degrees, and the actual background noise rate of the sun and the zenith angle theta of the sun of the ICESat-2 ATL03 data center are selected s Azimuth angle phi of sun s Data, selecting environmental parameters provided by the national environmental forecast center (National Centers for Environmental Prediction, NCEP) global analysis data set, including sea surface barometric pressure P, relative humidity RH, wind speed U 10 The optical thickness τ of the aerosol provided by a medium resolution imaging spectrometer (Moderate-resolution Imaging Spectroradiometer, MODIS) is selected a Water remote sensing reflectivity R rs These data are obtained by linear interpolation in space and time by means of the geographical location and time of the ICESat-2 transit. For ICESat-2/ATLAS, the system hardware parameters are known values, and in the embodiment, the values of the parameters are as follows: λ=532 nm, Δλ=0.038 nm, a r ＝0.503m 2 ，θ r ＝87.5/2μrad，θ v ＝0.38°，F＝0.52，η＝0.0735。
As shown in fig. 1, the method for estimating the ocean area noise of the satellite-borne single-photon laser radar adopted in the first embodiment specifically comprises the following steps:
step S1: back-scattering induced noise f of Rayleigh scattering r ：
Wherein F is the calibration coefficient of the spaceborne laser radar system of 0.52, eta is the efficiency of the whole receiving system of 0.0735, and comprises the receiving efficiency of an optical system and the quantum efficiency of a detector, and the wavelength N of 532nm adopted for the laser radar carried by ICESat-2 λ ＝1.832w/m 2 ·nm，θ v The angle of the nadir corresponding to the optical axis of the laser radar field of view is 0.38 DEG, theta r Is that the half field angle of the system is 87.5/2 mu rad, A r The caliber of the telescope is 0.503m 2 Hv is the single photon energy of 3.736505723684210e-19J, angle θ s And phi s The zenith angle and azimuth angle of the vector from the sea surface measurement point to the sun, respectively, can be obtained from an official release ATL03 dataset, where the solar zenith angle spans 28.8 ° to 41.2 °; θ v And phi v The space base angle and the azimuth angle from the ICESat-2 receiving telescope to the sea surface measuring point are respectively; θ ± ＝±θ s The method comprises the steps of carrying out a first treatment on the surface of the Δλ is the filter bandwidth; alpha is the scattering angle; r (theta) is the Fresnel reflectivity of the water-air interface when the incident angle is theta; τ r The rayleigh optical thickness is mainly related to the wavelength λ and the atmospheric pressure P.
The rayleigh scattering optical thickness at any atmospheric pressure can be expressed as:
wherein τ r0 Expressed at standard atmospheric pressure P 0 (1013.25 hPa), the Rayleigh optical thickness at a temperature of 288.15K, can be calculated as:
where λ corresponds to the center wavelength of the optical narrowband filter, typically λ is also the center wavelength of the emitted laser light in micrometers for a lidar system, and τ for a wavelength of 532nm r0 ＝0.1112。
Step S2: aerosol scattering noise term f caused by dust, smoke, cloud, etc a ：
Wherein w is a Is the aerosol single scattering ratio; a. g 1 、g 2 All are constants determined according to historical data, and the values of a=0.983 and g are generally suggested 1 ＝0.82、g 2 ＝﹣0.55；τ a Is the aerosol optical thickness, obtained from a MODIS data center, where the single scattering ratio can be expressed as:
w a ＝(-0.0032AM+0.972)*exp(3.06*10 -4 RH) (5)
where AM is an aerosol type and RH is the relative humidity of the atmosphere. AM ranges from 1 (typical open sea aerosol) to 10 (typical continental aerosol), with AM selection 1 in this example, rh being obtained from the NCEP data.
Step S3: the water surface reflection noise mainly comprises background light noise generated by water surface white foam reflection and background light noise generated by water surface specular reflection. Because of the wind wave on the sea surface, partial area on the water surface can be covered by foam, and the noise photon rate f of white foam reflection received by the spaceborne laser radar s,foam Can be expressed as:
wherein W is white foam coverage ratio, and the white foam coverage ratio of the ocean surface can be related to wind speedWind speed U 10 For a wind speed of 10m above the sea surface, the wind speed can be controlled from NCEPData center acquisition, ρ l Is white foam reflectance, 0.22, t (θ s ) And t (theta) v ) The atmospheric diffuse transmittance in the direction from ground to satellite and in the direction from sun to ground, respectively, can be obtained by looking up a table under the condition of known atmospheric optical thickness.
In the area where white foam is not covered, the water surface is in specular reflection, and the sunlight can be received by the receiving system only if the slope of the sea point just meets the direction of reflecting the sunlight to the satellite receiving telescope. Noise reflected at sea surface is expressed as:
wherein ρ is s The Fresnel reflectivity of the water surface is 0.02T for 532nm wavelength laser a Direct atmospheric transmittance s representing the direction of the zenith 2 For the root mean square slope of the sea surface, the correlation with wind speed can be expressed as s 2 ＝0.003+0.00512U 10 Wind speed U 10 Obtained from NCEP meteorological data.
Combining the two items, the total reflection noise item f of the water surface surf Can be expressed as:
f surf ＝f s,foam +f s,specular (8)
step S4: water body reflection noise item f w Can be expressed as:
here the remote sensing reflectivity R rs Obtained from the MODIS data.
Step S5: total background noise f detected by spaceborne lidar all Scattering noise term f by atmospheric Rayleigh r Atmospheric aerosol scattering noise term f a Total reflection noise term f of water surface surf Water body reflection noise item f w And detector dark count noise f d The composition is as follows:
f all ＝f r +f a +f surf +f w +f d (10)
according to the foregoing procedure, the solar altitude angle θ provided in the ICESat-2 ATL03 product is used in the examples s Azimuth angle phi s And its corresponding system hardware parameters, combined with sea surface atmospheric pressure P, relative humidity RH data and wind speed U of 10m above sea surface provided by NCEP 10 And an aerosol optical thickness τ provided by MODIS a Remote sensing reflectivity R rs The noise measured by the ICESat-2 system in this environment was finally estimated. The theoretical noise estimated by the invention is compared with the actual measured noise of ICESat-2 (supplied by ATL03 product). The orbit has a wide variation of various parameters, the latitude span is 9.5 degrees to 22.5 degrees, the solar zenith angle span is 28.8 degrees to 41.2 degrees, and the atmospheric optical thickness span is 0.09 to 0.28. As shown in FIG. 2, the solid black line represents the actual noise actually observed by the ICESat-2 system, and the dashed black line represents the theoretical noise rate of ICESat-2 estimated according to the method of the present invention. The absolute proportional error along the track direction (MAPE, mean Absolute Percentage Error) was 5.87%. Therefore, the invention can rapidly and accurately estimate the noise size of the satellite-borne single-photon laser radar through the input of the satellite-borne single-photon laser radar parameters and various environmental parameters, and is used for the optimization design of the satellite-borne laser radar ocean laser radar. For noise evaluation of other areas of the spaceborne single photon lidar, the Rayleigh scattering and aerosol scattering portions of the model remain applicable.
< example two >
In a second embodiment, a noise estimation system of a satellite-borne single-photon lidar capable of automatically implementing the method of the present invention is provided, where the system includes f r Calculation part f a Calculation part f surf Calculation part f w The laser radar system comprises a calculating part, a laser radar parameter optimizing part, a total noise calculating part, an input display part and a control part.
f r The calculation unit performs the above description of step 1 to calculate the atmospheric Rayleigh scattering noise f r 。
f a The calculation section performs the above-described step 2Content, calculate atmospheric aerosol scattering noise f a 。
f surf The calculating section performs the above-described contents of step 3 to calculate the water surface reflection noise f surf 。
f w The calculating part performs the above description of step 3 to calculate the reflection noise f of the water body below the water surface w 。
The total noise calculation unit is based on f r 、f a 、f surf 、f w Calculating total noise f of laser radar all 。
The laser radar parameter optimization part is based on f r 、f a 、f surf 、f w And total noise f of laser radar all And optimizing and configuring laser radar system parameters.
The input display part is used for enabling a user to input an operation instruction and displaying data of the corresponding part according to the operation instruction.
Control part and f r Calculation part f a Calculation part f surf Calculation part f w The calculation part, the laser radar parameter optimization part, the total noise calculation part and the input display part are all in communication connection and control the operation of the calculation part, the laser radar parameter optimization part, the total noise calculation part and the input display part;
the above embodiments are merely illustrative of the technical solutions of the present invention. The method and system for estimating the ocean area noise of the satellite-borne single-photon laser radar according to the present invention are not limited to the above embodiments, but the scope of the invention is defined by the claims. Any modifications, additions or equivalent substitutions made by those skilled in the art based on this embodiment are within the scope of the invention as claimed in the claims.
Claims (10)
1. The method for estimating the noise of the marine area of the satellite-borne single-photon laser radar is characterized by comprising the following steps of:
step 1, calculating the Rayleigh scattering noise f of the atmosphere r ：
Wherein F is the calibration coefficient of the satellite-borne laser radar system; η is the overall receive system efficiency including the optical system receive efficiency and the detector quantum efficiency; n (N) λ Is the irradiance of the sun outside the atmosphere; θ r Is the system receiving half field angle; a is that r The caliber of the telescope is; hv is the single photon energy; p (P) r Is a Rayleigh scattering phase function; angle theta s And phi s Zenith and azimuth angles, respectively, of the vector from the sea surface measurement point to the sun; r (theta) is the Fresnel reflectivity of the water-air interface when the incident angle is theta; τ r Is the rayleigh optical thickness; Δλ is the filter bandwidth; alpha is the scattering angle; θ v And phi v The space base angle and the azimuth angle from the ICESat-2 receiving telescope to the sea surface measuring point are respectively; θ ± ＝±θ s ，θ + ＝+θ s ，θ ﹣ ＝﹣θ s ；
Step 2, calculating the scattering noise f of the atmospheric aerosol a ：
Wherein w is a Is the single scattering ratio of aerosol, τ a Is the optical thickness of aerosol, a, g 1 、g 2 Are constants determined according to historical data;
step 3, calculating water surface reflection noise;
step 4, calculating water reflection noise below the water surface;
and 5, calculating the total noise of the laser radar based on the steps 1-4.
2. The method for estimating ocean area noise of a satellite-borne single-photon lidar according to claim 1, wherein the method comprises the steps of:
wherein in step 3, the water surface reflects noise f surf Including background light noise f generated by white foam reflection on water surface s,foam Specular reflection from water surfaceBackground light noise f generated s,specular ；
The background light noise generated by the specular reflection of the water surface is as follows:
wherein ρ is s Is the Fresnel reflectivity of the water surface; t (T) a Is the direct atmospheric transmittance in the direction of the zenith; s is(s) 2 Is the root mean square slope of the sea surface.
3. The method for estimating ocean area noise of on-board single photon lidar according to claim 2, wherein the method comprises the steps of:
wherein in step 2, a=0.983, g 1 ＝0.82、g 2 ＝﹣0.55；
In step 3, s 2 ＝0.003+0.00512U 10 ，U 10 Is the wind speed at 10 meters above the sea surface.
4. The method for estimating ocean area noise of a satellite-borne single-photon lidar according to claim 1, wherein the method comprises the steps of:
wherein in step 4, the water body reflects the noise f w ：
Wherein R is rs Is apparent optical coefficient remote sensing reflectivity.
5. The method for estimating ocean area noise of a satellite-borne single-photon lidar according to claim 1, wherein the method comprises the steps of:
wherein in step 5, the total noise f of the lidar all =atmospheric rayleigh scattering noise f r +atmospheric aerosol scattering noise f a +Water surface reflection noise f surf +Water reflection noise term f w +detector dark count noise f d 。
6. The noise estimation system of the satellite-borne single-photon laser radar is characterized by comprising the following components:
f r a calculation unit for calculating the Rayleigh scattering noise f of the atmosphere r ：
Wherein F is the calibration coefficient of the satellite-borne laser radar system; h is the overall receiving system efficiency, including the optical system receiving efficiency and the detector quantum efficiency; n (N) λ Is the irradiance of the sun outside the atmosphere; θ r Is the system receiving half field angle; a is that r The caliber of the telescope is; hv is the single photon energy; p (P) r Is a Rayleigh scattering phase function; angle theta s And phi s Zenith and azimuth angles, respectively, of the vector from the sea surface measurement point to the sun; r (theta) is the Fresnel reflectivity of the water-air interface when the incident angle is theta; τ r Is the rayleigh optical thickness; Δλ is the filter bandwidth; alpha is the scattering angle; θ v And phi v The space base angle and the azimuth angle from the ICESat-2 receiving telescope to the sea surface measuring point are respectively; θ ± ＝±θ s ，θ + ＝+θ s ，θ ﹣ ＝﹣θ s ；
f a A calculation unit for calculating the atmospheric aerosol scattering noise f a ：
Wherein w is a Is the single scattering ratio of aerosol, τ a Is the optical thickness of aerosol, a, g 1 、g 2 Are constants determined according to historical data;
total noise calculation unit based on f r 、f a Calculating total noise f of laser radar all ；
Control part, and f r Calculation part f a The calculation part and the total noise calculation part are all in communication connection and control the operation of the calculation part and the total noise calculation part.
7. The on-board single-photon lidar noise estimation system of claim 6, further comprising:
a laser radar parameter optimizing part which is communicated with the control part and is used for controlling the laser radar according to f r 、f a And total noise f of laser radar all And optimizing and configuring laser radar system parameters.
8. The on-board single-photon lidar noise estimation system of claim 7, further comprising:
f surf a calculation unit for calculating the water surface reflection noise f surf The method comprises the steps of carrying out a first treatment on the surface of the And
f w a calculation unit for calculating the reflection noise f of the water body below the water surface w ；
The noise estimation system of the satellite-borne single-photon laser radar is used for noise estimation in the ocean area;
the total noise calculation unit is based on f r 、f a 、f surf 、f w Calculating total noise f of laser radar all ；
Control part and f r Calculation part f a Calculation part f surf Calculation part f w The calculation part and the total noise calculation part are all in communication connection and control the operation of the calculation part and the total noise calculation part;
the laser radar parameter optimization part is based on f r 、f a 、f surf 、f w And total noise f of laser radar all And optimizing and configuring laser radar system parameters.
9. The on-board single-photon lidar noise estimation system of claim 6, further comprising:
and the input display part is in communication connection with the control part and is used for enabling a user to input an operation instruction and correspondingly display the operation instruction.
10. The on-board single-photon lidar noise estimation system of claim 8, wherein:
wherein at f surf In the calculating part, the water surface reflection noise f surf Including background light noise f generated by white foam reflection on water surface s,foam Background light noise f generated by specular reflection on water surface s,specular ；
The background light noise generated by the specular reflection of the water surface is as follows:
wherein ρ is s Is the Fresnel reflectivity of the water surface; t (T) a Is the direct atmospheric transmittance in the direction of the zenith; s is(s) 2 Is the root mean square slope of the sea surface.
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