阅读说明：本技术 一种Ka/C双频高度计消除电离层误差方法及系统 (Method and system for eliminating ionosphere error of Ka/C dual-frequency altimeter ) 是由 翟振和 杨双宝 李楠 管斌 于 2020-06-15 设计创作，主要内容包括：本发明公开了一种Ka/C双频高度计消除电离层误差方法及系统,Ka/C双频雷达高度计的Ka频段中心频率为35.7GHz,C频段中心频率为5.3GHz。该方法包括：根据Ka/C双频雷达高度计的回波波形测量值建立误差方程；采用最小二乘平差方法确定误差方程中的参数值；根据参数值得到Ka/C双频段测距改正值和双频段海况偏差改正值；根据Ka/C双频高度计观测值、Ka/C双频段测距改正值和Ka/C双频段海况偏差改正值综合确定Ka频段的电离层误差改正值。采用本发明的方法及系统,能够大幅减小电离层对卫星测高的影响,提高卫星测高精度。(The invention discloses a method and a system for eliminating an ionosphere error by a Ka/C dual-frequency altimeter, wherein the Ka-frequency band center frequency of the Ka/C dual-frequency radar altimeter is 35.7GHz, and the C-frequency band center frequency is 5.3 GHz. The method comprises the following steps: establishing an error equation according to the echo waveform measurement value of the Ka/C dual-frequency radar altimeter; determining parameter values in an error equation by adopting a least square adjustment method; obtaining a Ka/C double-frequency range measurement correction value and a double-frequency sea condition deviation correction value according to the parameter values; and comprehensively determining the ionospheric error correction value of the Ka frequency band according to the observed value of the Ka/C dual-frequency altimeter, the Ka/C dual-frequency range measurement correction value and the Ka/C dual-frequency band sea state deviation correction value. By adopting the method and the system, the influence of the ionized layer on the satellite height measurement can be greatly reduced, and the satellite height measurement precision is improved.)

1. A method for eliminating ionospheric errors by a Ka/C dual-frequency altimeter is characterized by comprising the following steps:

obtaining a Ka frequency range altimeter observation value, a C frequency range altimeter observation value and a radar echo waveform measurement value;

establishing an error equation according to the radar echo waveform measured value;

determining the value of a parameter in the error equation by adopting a least square adjustment method;

carrying out waveform retracing on the echo waveform of the Ka frequency range altimeter according to the parameter value to obtain a Ka frequency range ranging correction value; carrying out waveform retracing on the echo waveform of the altimeter of the C frequency band according to the parameter value to obtain a ranging correction value of the C frequency band; the parameter value is the value of the parameter in the error equation;

determining a Ka frequency band sea state deviation correction value and a C frequency band sea state deviation correction value by adopting a least square method according to the parameter values;

and determining an ionospheric error correction value of the Ka frequency band according to the Ka frequency band altimeter observation value, the C frequency band altimeter observation value, the Ka frequency band ranging correction value, the C frequency band ranging correction value, the Ka frequency band sea state deviation correction value and the C frequency band sea state deviation correction value.

2. The method for eliminating the ionospheric error of the Ka/C dual-frequency altimeter according to claim 1, wherein the establishing an error equation according to the radar echo waveform measurement value specifically includes:

an error equation is established according to the following formula:

V＝Ax-L

wherein x represents the correction value of a parameter including P_N、A₀、t_x、σ，P_NRepresenting the thermal noise level, A₀Representing the signal amplitude, t_xRepresenting the real tracking time of the altimeter, sigma representing the synthetic rise time of an echo waveform of the altimeter, L representing a radar echo waveform measured value, A representing the value of a partial derivative of a radar echo waveform function p (t) to-be-estimated parameter at an initial value, and V representing a residual error;

wherein the content of the first and second substances,

x＝(A^T·A)^-1(A^T·L)

in the formula, gamma_aRepresenting the antenna beamwidth parameter, ξ representing the off-the-sky nadir angle, τ representing the time epoch, erf representing the error function, and t representing each echoThe tracking time corresponding to each range gate in the waveform, d represents the intermediate variable, h represents the height relative to the reference ellipsoid, c represents the speed of light, and R represents the earth's radius.

3. The Ka/C dual-frequency altimeter ionospheric error removal method of claim 2,

the wave shape retracing is carried out on the echo wave shape of the Ka frequency range altimeter according to the parameter value to obtain a Ka frequency range ranging correction value, and the method specifically comprises the following steps:

carrying out waveform retracing on the echo waveform of the Ka frequency band altimeter according to the parameter value to obtain the actual tracking time of the rising front edge of the Ka frequency band waveform;

determining a Ka frequency range ranging correction value according to the actual tracking time of the rising front edge of the Ka frequency range waveform; the formula for determining the Ka frequency range ranging correction value is as follows:

in the formula (I), the compound is shown in the specification,

the wave form retracing is carried out on the echo wave form of the C-band altimeter according to the parameter value to obtain a C-band ranging correction value, and the method specifically comprises the following steps:

carrying out waveform retracing on the echo waveform of the altimeter of the C frequency band according to the parameter value to obtain the actual tracking time of the rising front edge of the waveform of the C frequency band;

determining a C-band ranging correction value according to the actual tracking time of the rising front edge of the C-band waveform; the formula for determining the C-band ranging correction value is as follows:

in the formula (I), the compound is shown in the specification,

4. The method for eliminating the ionospheric error of the Ka/C dual-frequency altimeter according to claim 3, wherein the determining the Ka-band sea state deviation correction value and the C-band sea state deviation correction value by using a least square method according to the parameter value specifically comprises:

determining the sea state deviation correction value of the Ka frequency band according to the following formula:

swh_ka＝2c(σ_ka ²-2.57)^1/2

in the formula (I), the compound is shown in the specification,

determining the sea state deviation correction value of the C frequency band according to the following formula:

swh_c＝2c(σ_c ²-2.57)^1/2

in the formula (I), the compound is shown in the specification,indicating the correction value of the sea state deviation in the C-band, swh_cRepresenting the effective wave height, σ, of the C band_cAnd the composite rise time of the echo waveform of the altimeter in the C frequency band is shown.

5. The method for eliminating the ionospheric error by the Ka/C dual-band altimeter of claim 4, wherein the determining the ionospheric error correction value of the Ka band based on the Ka-band altimeter observation value, the C-band altimeter observation value, the Ka-band ranging correction value, the C-band ranging correction value, the Ka-band sea state deviation correction value, and the C-band sea state deviation correction value specifically comprises:

determining an ionospheric error correction value for the Ka band according to the following equation:

in the formula, I (f)_ka) The ionospheric error correction values representing the Ka band,represents the observed values of the Ka-band altimeter,

6. A system for eliminating ionospheric errors by a Ka/C dual-frequency altimeter is characterized by comprising:

the data acquisition module is used for acquiring an observed value of a Ka-band altimeter, an observed value of a C-band altimeter and a radar echo waveform measured value;

the error equation establishing module is used for establishing an error equation according to the radar echo waveform measured value;

the parameter value determining module is used for determining the value of the parameter in the error equation by adopting a least square adjustment method;

the ranging correction value determining module is used for carrying out waveform retracing on the echo waveform of the Ka frequency range altimeter according to the parameter value to obtain a Ka frequency range ranging correction value; carrying out waveform retracing on the echo waveform of the altimeter of the C frequency band according to the parameter value to obtain a ranging correction value of the C frequency band; the parameter value is the value of the parameter in the error equation;

the sea state deviation correction value determining module is used for determining a Ka frequency band sea state deviation correction value and a C frequency band sea state deviation correction value by adopting a least square method according to the parameter values;

and the ionospheric error correction value determining module is used for determining the ionospheric error correction value of the Ka frequency band according to the Ka frequency band altimeter observation value, the C frequency band altimeter observation value, the Ka frequency band ranging correction value, the C frequency band ranging correction value, the Ka frequency band sea state deviation correction value and the C frequency band sea state deviation correction value.

7. The system for eliminating ionospheric errors by a Ka/C dual-frequency altimeter of claim 6, wherein the error equation establishing module specifically comprises:

an error equation establishing unit for establishing an error equation according to the following formula:

V＝Ax-L

wherein x represents the correction value of a parameter including P_N、A₀、t_x、σ，P_NRepresenting the thermal noise level, A₀Representing the signal amplitude, t_xRepresenting the real tracking time of the altimeter, sigma representing the synthetic rise time of an echo waveform of the altimeter, L representing a radar echo waveform measured value, A representing the value of a partial derivative of a radar echo waveform function p (t) to-be-estimated parameter at an initial value, and V representing a residual error;

wherein the content of the first and second substances,

x＝(A^T·A)^-1(A^T·L)

in the formula, gamma_aRepresenting the antenna beam width parameter, ξ representing the off-the-sky nadir angle, τ representing the time epoch, erf representing the error function, t representing the tracking time for each range gate in each echo waveform, d representing the intermediate variable, h representing the height relative to the reference ellipsoid, c representing the speed of light, and R representing the earth radius.

8. The system for eliminating ionospheric error of a Ka/C dual-frequency altimeter of claim 7, wherein the ranging correction value determination module specifically comprises:

the Ka frequency range distance measurement correction value determining unit is used for carrying out waveform retracing on the echo waveform of the Ka frequency range altimeter according to the parameter value to obtain a Ka frequency range distance measurement correction value;

the Ka band ranging correction value determining unit specifically includes:

the first actual tracking time determining subunit is used for performing waveform retracing on the echo waveform of the Ka frequency band altimeter according to the parameter value to obtain the actual tracking time of the rising front edge of the Ka frequency band waveform;

a Ka frequency range measurement correction value determining subunit, configured to determine a Ka frequency range measurement correction value according to the actual tracking time of the rising front edge of the Ka frequency range waveform; the formula for determining the Ka frequency range ranging correction value is as follows:

in the formula (I), the compound is shown in the specification,indicating a Ka-band ranging correction value,indicating the actual tracking time, Nor, of the rising front of the Ka band waveform_tRepresenting the time corresponding to the normal tracking point;

the C-band ranging correction value determining unit is used for performing waveform retracing on the echo waveform of the altimeter of the C-band according to the parameter value to obtain a C-band ranging correction value;

the C-band ranging correction value determining unit specifically includes:

the second actual tracking time determining subunit is used for performing waveform retracing on the echo waveform of the altimeter of the C-band according to the parameter value to obtain the actual tracking time of the rising front edge of the waveform of the C-band;

the C-band ranging correction value determining subunit is used for determining the C-band ranging correction value according to the actual tracking time of the rising front edge of the C-band waveform; the formula for determining the C-band ranging correction value is as follows:

in the formula (I), the compound is shown in the specification,indicating a C-band ranging correction value,representing the actual tracking time of the rising front of the C-band waveform.

9. The system for eliminating ionospheric error of a Ka/C dual-frequency altimeter of claim 8, wherein the sea state bias correction value determining module specifically comprises:

the Ka frequency band sea state deviation correction value determining unit is used for determining the Ka frequency band sea state deviation correction value according to the following formula:

swh_ka＝2c(σ_ka ²-2.57)^1/2

in the formula (I), the compound is shown in the specification,

the C frequency band sea state deviation correction value determining unit is used for determining the C frequency band sea state deviation correction value according to the following formula:

swh_c＝2c(σ_c ²-2.57)^1/2

in the formula (I), the compound is shown in the specification,

10. The Ka/C dual-frequency altimeter ionospheric error mitigation system of claim 9, wherein the ionospheric error correction value determination module specifically comprises:

an ionospheric error correction value determination unit configured to determine an ionospheric error correction value of the Ka band according to the following formula:

in the formula, I (f)_ka) The ionospheric error correction values representing the Ka band,represents the observed values of the Ka-band altimeter,represents the altimeter observed value of C frequency band, f_kaRepresenting frequencies of Ka-band, f_cRepresenting frequencies in the C band.

Technical Field

The invention relates to the technical field of marine satellite height measurement, in particular to a method and a system for eliminating ionosphere errors by a Ka/C dual-frequency altimeter.

Background

The marine satellite height measurement technology is an important means for acquiring sea surface changes, gravitational fields and submarine topography in global marine areas. The ionospheric error is one of the main errors in satellite height measurement, at present, most height measurement satellites generally adopt a Ku/C dual-frequency system to eliminate the ionospheric layer, and few height measurement satellites adopt a single-frequency Ka system, and the two systems have certain defects in the aspect of correcting the ionospheric error. Although the Ku/C dual-frequency system can greatly reduce the influence of ionosphere errors, a noise error of 0.5-1cm exists for centimeter-level height measurement, and the measurement accuracy of a Ku frequency band to a near-shore and ice region is lower than that of a Ka frequency band; although the Ka frequency range is high in ranging accuracy, data failure is caused by the influence of rainfall, and ionosphere influence cannot be completely eliminated by single Ka frequency range ranging.

Disclosure of Invention

The invention aims to provide a method and a system for eliminating ionosphere errors by a Ka/C dual-frequency altimeter, which can reduce the influence of an ionosphere on satellite height measurement and improve the satellite height measurement precision.

In order to achieve the purpose, the invention provides the following scheme:

a method for eliminating satellite height measurement ionosphere errors by combining a dual-frequency radar altimeter comprises the following steps:

obtaining a Ka frequency range altimeter observation value, a C frequency range altimeter observation value and a radar echo waveform measurement value;

establishing an error equation according to the radar echo waveform measured value;

determining the value of a parameter in the error equation by adopting a least square adjustment method;

carrying out waveform retracing on the echo waveform of the Ka frequency range altimeter according to the parameter value to obtain a Ka frequency range ranging correction value; carrying out waveform retracing on the echo waveform of the altimeter of the C frequency band according to the parameter value to obtain a ranging correction value of the C frequency band; the parameter value is the value of the parameter in the error equation;

determining a Ka frequency band sea state deviation correction value and a C frequency band sea state deviation correction value by adopting a least square method according to the parameter values;

and determining an ionospheric error correction value of the Ka frequency band according to the Ka frequency band altimeter observation value, the C frequency band altimeter observation value, the Ka frequency band ranging correction value, the C frequency band ranging correction value, the Ka frequency band sea state deviation correction value and the C frequency band sea state deviation correction value.

Optionally, the establishing an error equation according to the radar echo waveform measurement value specifically includes:

an error equation is established according to the following formula:

V＝Ax-L

wherein x represents the correction value of a parameter including P_N、A₀、t_x、σ，P_NRepresenting the thermal noise level, A₀Representing the signal amplitude, t_xRepresenting the real tracking time of the altimeter, sigma representing the synthetic rise time of an echo waveform of the altimeter, L representing a radar echo waveform measured value, A representing the value of a partial derivative of a radar echo waveform function p (t) to-be-estimated parameter at an initial value, and V representing a residual error;

wherein the content of the first and second substances,

x＝(A^T·A)^-1(A^T·L)

in the formula, gamma_aRepresenting the antenna beam width parameter, ξ representing the angle of the off-the-sky nadir, τ representing the time epoch, erf representing the error function, t representing the tracking time for each range gate in each echo waveform, d representing the intermediate variable, h representing the height relative to the reference ellipsoid, c representing the speed of light, R representing the earth's beam width parameterA radius.

Alternatively to this, the first and second parts may,

the wave shape retracing is carried out on the echo wave shape of the Ka frequency range altimeter according to the parameter value to obtain a Ka frequency range ranging correction value, and the method specifically comprises the following steps:

carrying out waveform retracing on the echo waveform of the Ka frequency band altimeter according to the parameter value to obtain the actual tracking time of the rising front edge of the Ka frequency band waveform;

determining a Ka frequency range ranging correction value according to the actual tracking time of the rising front edge of the Ka frequency range waveform; the formula for determining the Ka frequency range ranging correction value is as follows:

in the formula (I), the compound is shown in the specification,

indicating a Ka-band ranging correction value,indicating the actual tracking time, Nor, of the rising front of the Ka band waveform_tRepresenting the time corresponding to the normal tracking point;

the wave form retracing is carried out on the echo wave form of the C-band altimeter according to the parameter value to obtain a C-band ranging correction value, and the method specifically comprises the following steps:

carrying out waveform retracing on the echo waveform of the altimeter of the C frequency band according to the parameter value to obtain the actual tracking time of the rising front edge of the waveform of the C frequency band;

determining a C-band ranging correction value according to the actual tracking time of the rising front edge of the C-band waveform; the formula for determining the C-band ranging correction value is as follows:

in the formula (I), the compound is shown in the specification,indicating a C-band ranging correction value,representing the actual tracking time of the rising front of the C-band waveform.

Optionally, the determining the Ka frequency band sea state deviation correction value and the C frequency band sea state deviation correction value by using a least square method according to the parameter value specifically includes:

determining the sea state deviation correction value of the Ka frequency band according to the following formula:

swh_ka＝2c(σ_ka ²-2.57)^1/2

in the formula (I), the compound is shown in the specification,

indicating the correction value of sea state deviation in Ka band, swh_kaRepresents the effective wave height of Ka frequency band, U represents the wind speed, sigma_kaRepresenting the rise time, a, of echo waveform synthesis of the altimeter in Ka frequency band₁、a₂、a₃、a₄Are all constant parameters;

determining the sea state deviation correction value of the C frequency band according to the following formula:

swh_c＝2c(σ_c ²-2.57)^1/2

in the formula (I), the compound is shown in the specification,

indicating the correction value of the sea state deviation in the C-band, swh_cRepresenting the effective wave height, σ, of the C band_cAnd the composite rise time of the echo waveform of the altimeter in the C frequency band is shown.

Optionally, the determining an ionospheric error correction value of the Ka band according to the Ka band altimeter observation value, the C band altimeter observation value, the Ka band ranging correction value, the C band ranging correction value, the Ka band sea state deviation correction value, and the C band sea state deviation correction value specifically includes:

determining an ionospheric error correction value for the Ka band according to the following equation:

in the formula, I (f)_ka) The ionospheric error correction values representing the Ka band,represents the observed values of the Ka-band altimeter,represents the altimeter observed value of C frequency band, f_kaRepresenting frequencies of Ka-band, f_cRepresenting frequencies in the C band.

The invention also provides a system for eliminating the ionospheric error by the Ka/C dual-frequency altimeter, which comprises:

the data acquisition module is used for acquiring an observed value of a Ka-band altimeter, an observed value of a C-band altimeter and a radar echo waveform measured value;

the error equation establishing module is used for establishing an error equation according to the radar echo waveform measured value;

the parameter value determining module is used for determining the value of the parameter in the error equation by adopting a least square adjustment method;

the ranging correction value determining module is used for carrying out waveform retracing on the echo waveform of the Ka frequency range altimeter according to the parameter value to obtain a Ka frequency range ranging correction value; carrying out waveform retracing on the echo waveform of the altimeter of the C frequency band according to the parameter value to obtain a ranging correction value of the C frequency band; the parameter value is the value of the parameter in the error equation;

the sea state deviation correction value determining module is used for determining a Ka frequency band sea state deviation correction value and a C frequency band sea state deviation correction value by adopting a least square method according to the parameter values;

and the ionospheric error correction value determining module is used for determining the ionospheric error correction value of the Ka frequency band according to the Ka frequency band altimeter observation value, the C frequency band altimeter observation value, the Ka frequency band ranging correction value, the C frequency band ranging correction value, the Ka frequency band sea state deviation correction value and the C frequency band sea state deviation correction value.

Optionally, the error equation establishing module specifically includes:

an error equation establishing unit for establishing an error equation according to the following formula:

V＝Ax-L

wherein x represents the correction value of a parameter including P_N、A₀、t_x、σ，P_NRepresenting the thermal noise level, A₀Representing the signal amplitude, t_xRepresenting the real tracking time of the altimeter, sigma representing the synthetic rise time of an echo waveform of the altimeter, L representing a radar echo waveform measured value, A representing the value of a partial derivative of a radar echo waveform function p (t) to-be-estimated parameter at an initial value, and V representing a residual error;

wherein the content of the first and second substances,

x＝(A^T·A)^-1(A^T·L)

in the formula, gamma_aRepresenting the antenna beam width parameter, ξ representing the off-the-sky nadir angle, τ representing the time epoch, erf representing the error function, t representing the tracking time for each range gate in each echo waveform, d representing the middleThe variables, h, denote the height relative to a reference ellipsoid, c, the speed of light, and R, the radius of the earth.

Optionally, the ranging correction value determining module specifically includes:

the Ka frequency range distance measurement correction value determining unit is used for carrying out waveform retracing on the echo waveform of the Ka frequency range altimeter according to the parameter value to obtain a Ka frequency range distance measurement correction value;

the Ka band ranging correction value determining unit specifically includes:

the first actual tracking time determining subunit is used for performing waveform retracing on the echo waveform of the Ka frequency band altimeter according to the parameter value to obtain the actual tracking time of the rising front edge of the Ka frequency band waveform;

a Ka frequency range measurement correction value determining subunit, configured to determine a Ka frequency range measurement correction value according to the actual tracking time of the rising front edge of the Ka frequency range waveform; the formula for determining the Ka frequency range ranging correction value is as follows:

in the formula (I), the compound is shown in the specification,indicating a Ka-band ranging correction value,indicating the actual tracking time, Nor, of the rising front of the Ka band waveform_tRepresenting the time corresponding to the normal tracking point;

the C-band ranging correction value determining unit is used for performing waveform retracing on the echo waveform of the altimeter of the C-band according to the parameter value to obtain a C-band ranging correction value;

the C-band ranging correction value determining unit specifically includes:

the second actual tracking time determining subunit is used for performing waveform retracing on the echo waveform of the altimeter of the C-band according to the parameter value to obtain the actual tracking time of the rising front edge of the waveform of the C-band;

the C-band ranging correction value determining subunit is used for determining the C-band ranging correction value according to the actual tracking time of the rising front edge of the C-band waveform; the formula for determining the C-band ranging correction value is as follows:

in the formula (I), the compound is shown in the specification,indicating a C-band ranging correction value,representing the actual tracking time of the rising front of the C-band waveform.

Optionally, the sea state deviation correction value determining module specifically includes:

the Ka frequency band sea state deviation correction value determining unit is used for determining the Ka frequency band sea state deviation correction value according to the following formula:

swh_ka＝2c(σ_ka ²-2.57)^1/2

in the formula (I), the compound is shown in the specification,indicating the correction value of sea state deviation in Ka band, swh_kaRepresents the effective wave height of Ka frequency band, U represents the wind speed, sigma_kaRepresenting the rise time, a, of echo waveform synthesis of the altimeter in Ka frequency band₁、a₂、a₃、a₄Are all constant parameters;

the C frequency band sea state deviation correction value determining unit is used for determining the C frequency band sea state deviation correction value according to the following formula:

swh_c＝2c(σ_c ²-2.57)^1/2

in the formula (I), the compound is shown in the specification,indicating the correction value of the sea state deviation in the C-band, swh_cRepresenting the effective wave height, σ, of the C band_cAnd the composite rise time of the echo waveform of the altimeter in the C frequency band is shown.

Optionally, the ionospheric error correction value determining module specifically includes:

an ionospheric error correction value determination unit configured to determine an ionospheric error correction value of the Ka band according to the following formula:

in the formula, I (f)_ka) The ionospheric error correction values representing the Ka band,represents the observed values of the Ka-band altimeter,represents the altimeter observed value of C frequency band, f_kaRepresenting frequencies of Ka-band, f_cRepresenting frequencies in the C band.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a method and a system for eliminating an ionosphere error by a Ka/C dual-frequency altimeter, wherein the Ka frequency band central frequency of the Ka/C dual-frequency radar altimeter is 35.7GHz, and the C frequency band central frequency is 5.3 GHz; determining the value of a parameter in an error equation by adopting a least square adjustment method; obtaining a Ka/C double-frequency range measurement correction value and a double-frequency sea condition deviation correction value according to the parameter values; and comprehensively determining the ionospheric error correction value of the Ka frequency band according to the observed value of the Ka/C dual-frequency altimeter, the Ka/C dual-frequency range measurement correction value and the Ka/C dual-frequency band sea state deviation correction value. By adopting the method and the system, the influence of the ionosphere on satellite height measurement can be greatly reduced, the satellite height measurement precision is improved, the influence of the ionosphere can be eliminated to 0.8-1mm magnitude, and the requirement of the marine satellite on the precision of 1cm height measurement is met.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a flow chart of a method for eliminating satellite height measurement ionosphere errors by the Ka/C dual-frequency radar altimeter combination in the embodiment of the invention;

FIG. 2 is a flow chart of ionospheric error correction calculation according to an embodiment of the present invention;

FIG. 3 is a ka band marine altimetry echo waveform diagram in an embodiment of the present invention;

FIG. 4 is a C-band marine altimetry echo waveform diagram in an embodiment of the present invention;

FIG. 5 is a block diagram of a system for eliminating satellite height measurement ionospheric error by the Ka/C dual-band radar altimeter combination in an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a method and a system for eliminating ionosphere errors by a Ka/C dual-frequency altimeter, which can reduce the influence of an ionosphere on satellite height measurement and improve the satellite height measurement precision.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.