Beidou navigation satellite signal ground-based monitoring method and system

Abstract

The application discloses a Beidou navigation satellite signal ground-based monitoring method and system, and comprises the following steps: obtaining ground-based system receiving power P R (θ, φ) through signal power received by a ground-based receiving station R (θ, φ) according to preset product information of an antenna of the ground-based monitoring station; obtaining a transmission distance according to positions of the ground-based receiving station and the Beidou navigation satellite; and obtaining equivalent omnidirectional radiation power of the Beidou navigation satellite according to the ground-based system receiving power P R (θ, φ), the antenna pattern G R (θ, φ) and the transmission distance. The application solves the bottleneck problem of the Beidou system of China in the process of quantitative remote sensing application.

Description

Technical Field

[0001] This invention belongs to the field of microwave remote sensing technology, and in particular relates to a ground-based monitoring method and system for BeiDou navigation satellite signals. Background Technology

[0002] The development of remote sensing applications using the BeiDou system's reflected signal (BDS-R) lags behind the world's leading levels. Existing foreign GNSS-R remote sensing satellite programs only consider the US Global Positioning System-Reflectometry (GPS-R) signal. For a long time, the only operational GNSS-R remote sensing satellite constellation in orbit was NASA's CYclone Global Navigation Satellite System (CYGNSS), whose marine and land operational products have undergone dozens of version updates, and its application areas are constantly expanding. Unfortunately, NASA only publishes compressed process products, and a large amount of researchable content is only available to the United States and related countries, which has greatly affected China's rapid development and progress in this field. On June 5, 2019, the successful in-orbit deployment of China's first-generation GNSS-R remote sensing satellite constellation compatible with the BeiDou system and in-orbit calibration payload—the "Catch the Wind-1" experimental twin satellites—broke this pattern and filled the gap in China's spaceborne GNSS-R remote sensing field.

[0003] However, the problem with "Wind Catcher-1" is that although it can receive reflected signals from the BeiDou system, the lack of ground-based monitoring products for BeiDou navigation satellite signals results in the absence of the transmission power spectrum of different navigation satellites, which is the most critical part of the theoretical model. This ultimately leads to the bottleneck problem of not being able to perform quantitative remote sensing processing on the received signals, making it difficult to obtain corresponding geophysical remote sensing products, which greatly affects the development process of remote sensing applications of the BeiDou system in my country. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a ground-based monitoring method and system for BeiDou navigation satellite signals, which solves the bottleneck problem in the quantitative remote sensing application of my country's BeiDou system.

[0005] The objective of this invention is achieved through the following technical solution: a ground-based monitoring method for BeiDou navigation satellite signals, comprising: obtaining the received power P of the ground system through the signal power received by the ground-based receiving station. R (θ,φ); The antenna pattern G is obtained based on the product information of the antenna of the preset ground-based monitoring station. R(θ,φ); the transmission distance is obtained based on the location of the ground-based receiving station and the location of the BeiDou navigation satellite; the transmission distance is obtained based on the receiving power P of the ground-based system. R (θ,φ), Antenna pattern G R The equivalent isotropic radiated power of the BeiDou navigation satellite is obtained from (θ,φ) and transmission distance.

[0006] In the above-mentioned ground-based monitoring method for BeiDou navigation satellite signals, the received power of the ground-based system is obtained by the following formula:

[0007] P R (θ,φ)=S B C BDS ;

[0008] Among them, P R (θ,φ) represents the received power of the ground system, S B θ is the scale factor, φ is the elevation angle of the BeiDou navigation satellite, and C is the azimuth angle of the BeiDou navigation satellite. BDS This represents the power-related value received by the ground-based receiver.

[0009] In the aforementioned ground-based monitoring method for BeiDou navigation satellite signals, the scale factor S B Obtained through a lookup table of low-noise amplifiers in the BeiDou power monitoring system.

[0010] In the above-mentioned ground-based monitoring method for BeiDou navigation satellite signals, the transmission distance is obtained using the following formula:

[0011]

[0012] Where R is the transmission distance, X T The X and Y coordinates of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system are... T The Y and Z coordinates of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system are... T The Z coordinate and X coordinate in the geocentric-ground-fixed coordinate system of the BeiDou navigation satellite are given. R The X and Y coordinates of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system are... R The Y-coordinate and Z-coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system are... R The Z-coordinate is the coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system.

[0013] In the above-mentioned ground-based monitoring method for BeiDou navigation satellite signals, the equivalent isotropic radiated power of the BeiDou navigation satellite is obtained through the following formula:

[0014]

[0015] Among them, E PRN (θ,φ) represents the equivalent isotropic radiated power of the BeiDou navigation satellite, P R(θ,φ) represents the received power of the ground-based system, R represents the transmission distance, and G represents the received power of the ground-based system. R (θ,φ) represents the antenna pattern, where θ is the elevation angle of the BeiDou navigation satellite, φ is the azimuth angle of the BeiDou navigation satellite, and C is a constant.

[0016] A ground-based monitoring system for BeiDou navigation satellite signals includes: a first module, used to obtain the received power P of the ground system through the signal power received by the ground-based receiving station. R (θ,φ); The second module is used to obtain the antenna pattern G based on the product information of the antenna of the preset ground-based monitoring station. R (θ,φ); The third module is used to obtain the transmission distance based on the location of the ground-based receiving station and the location of the BeiDou navigation satellites; the fourth module is used to determine the transmission distance based on the received power P of the ground-based system. R (θ,φ), Antenna pattern G R The equivalent isotropic radiated power of the BeiDou navigation satellite is obtained from (θ,φ) and transmission distance.

[0017] In the aforementioned BeiDou navigation satellite signal ground-based monitoring system, the received power of the ground-based system is obtained using the following formula:

[0018] P R (θ,φ)=S B C BDS ;

[0019] Among them, P R (θ,φ) represents the received power of the ground system, S B θ is the scale factor, φ is the elevation angle of the BeiDou navigation satellite, and C is the azimuth angle of the BeiDou navigation satellite. BDS This represents the power correlation value received by the ground-based receiver of the BeiDou navigation satellite signal.

[0020] In the aforementioned ground-based monitoring system for BeiDou navigation satellite signals, the scale factor S B Obtained through a lookup table of low-noise amplifiers in the BeiDou power monitoring system.

[0021] In the aforementioned BeiDou navigation satellite signal ground-based monitoring system, the transmission distance is obtained using the following formula:

[0022]

[0023] Where R is the transmission distance, X T The X and Y coordinates of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system are... T The Y and Z coordinates of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system are... T The Z coordinate and X coordinate in the geocentric-ground-fixed coordinate system of the BeiDou navigation satellite are given. R The X and Y coordinates of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system are... RThe Y-coordinate and Z-coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system are... R The Z-coordinate is the coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system.

[0024] In the aforementioned BeiDou navigation satellite signal ground-based monitoring system, the equivalent isotropic radiated power of the BeiDou navigation satellite is obtained using the following formula:

[0025]

[0026] Among them, E PRN (θ,φ) represents the equivalent isotropic radiated power of the BeiDou navigation satellite, P R (θ,φ) represents the received power of the ground-based system, R represents the transmission distance, and G represents the received power of the ground-based system. R (θ,φ) represents the antenna pattern, where θ is the elevation angle of the BeiDou navigation satellite, φ is the azimuth angle of the BeiDou navigation satellite, and C is a constant.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) This invention obtains the transmission power and gain of each Beidou navigation satellite under different incident directions by acquiring the equivalent omnidirectional radiation power of the Beidou system, thereby overcoming the bottleneck problem of uncertainty in the power of the transmitter during quantitative remote sensing applications;

[0029] (2) The present invention can monitor the power of the Beidou system all day and all weather through the Beidou navigation satellite signal ground-based monitoring system. It can not only obtain the final equivalent omnidirectional radiation power of the Beidou system, but also obtain effective information such as sudden power adjustment during the operation of the Beidou system, the unique signal physical characteristics of the Beidou system, ground-based atmospheric observation results, and high-precision single-point positioning with certain service capabilities. Attached Figure Description

[0030] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0031] Figure 1 This is a flowchart of the BeiDou navigation satellite signal ground-based monitoring method provided in an embodiment of the present invention;

[0032] Figure 2 This is a graph showing the change in received power over time of the ground-based monitoring system provided in this embodiment of the invention;

[0033] Figure 3 This is a graph showing the change of antenna gain over time in the ground-based monitoring system provided in an embodiment of the present invention;

[0034] Figure 4 This is a graph showing the change in distance over time between the ground-based monitoring system and navigation satellites provided in this embodiment of the invention.

[0035] Figure 5 This is a graph showing the change in elevation angle over time received by the ground monitoring system provided in this embodiment of the invention;

[0036] Figure 6 This is a graph showing the change of the receiving azimuth angle over time in the ground-based monitoring system provided in this embodiment of the invention;

[0037] Figure 7 This is the equivalent omnidirectional radiation power map obtained by the ground monitoring system provided in the embodiments of the present invention. Detailed Implementation

[0038] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] Figure 1 This is a flowchart of the BeiDou navigation satellite signal ground-based monitoring method provided in an embodiment of the present invention. Figure 1 As shown, the method includes the following steps:

[0040] The received power P of the ground system is obtained by the signal power received by the ground receiving station. R (θ,φ);

[0041] The antenna pattern G is obtained based on the product information of the antenna of the pre-set ground-based monitoring station. R (θ,φ);

[0042] The transmission distance is determined based on the location of the ground-based receiving station and the location of the BeiDou navigation satellites.

[0043] According to the received power P of the foundation system R (θ,φ), Antenna pattern G R The equivalent isotropic radiated power of the BeiDou navigation satellite is obtained from (θ,φ) and transmission distance.

[0044] Specifically, this invention can be applied to situations where the equivalent isotropic radiative power spectrum (EIRP) is unknown in quantitative remote sensing applications of the BeiDou system. First, the ground-based EIRP monitoring equation for the BeiDou system is determined based on the Frings transmission equation, identifying the required monitoring parameters. Then, the received power and antenna pattern of the ground-based system are acquired, the transmission distance is calculated, and finally, the BeiDou system EIRP product is output. The specific implementation steps are as follows:

[0045] Step 1: Determine the BeiDou system ground-based EIRP monitoring equations based on the Frings transmission equations:

[0046] First, establish the Fringes transport equation:

[0047]

[0048] Among them, P R Base station system received power, E is the EIRP of the BeiDou system in a certain direction, R is the transmission distance, L a The atmospheric loss coefficient can be established as an empirical function based on the location of the ground-based observation station, where λ is the wavelength of the BeiDou signal, and G... R Let E be the gain of the receiving antenna. Rearranging the equation, we place the unknown quantity E, which we need to obtain, on the left side of the equation:

[0049]

[0050] Step 2: Determine the parameters required for monitoring:

[0051] Observe and obtain the unknowns from the rearranged equation:

[0052] P is obtained by measuring the different signal powers received by the ground-based receiving station. R Ground system received power;

[0053] G is obtained from the antenna pattern of the ground-based receiving station. R Antenna gain;

[0054] The R transmission distance is obtained based on the XYZ position of the ground-based receiving station and the XYZ position of the satellite.

[0055] Step 3: Ground system received power acquisition (P) R ):

[0056] The signal P received by the Beidou navigation signal receiving antenna R The following relationship exists between the correlation value BDS obtained by the BeiDou navigation receiver and the BDS:

[0057] P R (θ,φ)=S B C BDS

[0058] Among them, SB The scaling factor is obtained through a lookup table of low-noise amplifiers in the BeiDou power monitoring system. θ, φ, and PRN represent P R This refers to the receiving power of a specific BeiDou navigation satellite at a given elevation and azimuth angle at a specific moment.

[0059] Step 4: Antenna pattern acquisition (G R ):

[0060] Antenna pattern G R (θ,φ) are obtained directly from the product information of the antenna of the ground-based monitoring station.

[0061] Step 5: Transmission distance calculation (R):

[0062] Through long-term monitoring by ground-based receiving stations, a precise self-positioning location (X) can be obtained. R Y R Z R Furthermore, based on the precise ephemeris of BeiDou, it is possible to obtain information on navigation satellites (X) at different times and from different PRNs. T Y T Z T The transmission distance can be obtained by subtracting the two and taking the modulus, as follows:

[0063]

[0064] Step 6: Output BeiDou system EIRP products:

[0065] Steps 3, 4, and 5 above complete the parameters required for ground-based EIRP monitoring in step 1. The final product, based on each BeiDou navigation satellite, is as follows:

[0066]

[0067] Among them, E PRN (θ,φ) represents the EIRP of a BeiDou navigation satellite at the corresponding elevation and azimuth angles; where the observation angular resolution of elevation angle θ and azimuth angle φ is 1 degree, and C is a constant; P R G R R and R come from steps 3, 4, and 5, respectively.

[0068] The effectiveness of the invention will be further illustrated below through EIRP monitoring of GPS satellites:

[0069] Experimental Test: By analyzing a full day's worth of GPS data received by the GPS receiver, the various parameters required for monitoring are output in a time series. The first step is P from step 3. R The output result is as follows Figure 2As shown, the horizontal axis represents the time series, and the vertical axis represents the GPS ground-based system received power at each time point, in dB. Next, the antenna gain (G) in step 4 is calculated based on the antenna pattern. R The acquisition of ) such as Figure 3 As shown, the horizontal axis represents the time series, and the vertical axis represents the antenna gain at each time point, in dB. Finally, the transmission distance (R) corresponding to step 5 is calculated, as follows: Figure 4 As shown, the horizontal axis represents the time series, and the vertical axis represents the signal transmission distance at each time point, in meters (m). Finally, the results from steps 3, 4, and 5 are substituted into the equation in step 6 to obtain the ERIP observation values ​​at the corresponding times. Simultaneously, it is also necessary to record the satellite number and its corresponding elevation and azimuth angles for each time point, as shown below. Figure 5 and Figure 6 As shown, the horizontal axis represents time series data, and the vertical axis is in degrees. Finally, based on the above information, a 360-degree (azimuth) × 90-degree (elevation) matrix is ​​constructed. Each matrix grid corresponds to the relevant ERIP calculation results, yielding the EIRP product, as shown below. Figure 7 As shown in the figure, three-dimensional polar coordinates are used for display.

[0070] Experimental Conclusion: The detailed explanation of the steps in this invention, based on a day's worth of actual navigation signals obtained using a GPS receiver, reveals that while some gaps exist due to insufficient observations to cover all scenarios, the ERIPs at the corresponding angles already observed can be used for quantitative remote sensing of navigation satellite signals. Ultimately, this invention will be geared towards ground-based monitoring of the BDS BeiDou system, where the observations in steps 3, 4, and 5 will be replaced with BeiDou system observations to obtain the ground-based monitoring results of the BeiDou navigation satellite system's EIRP.

[0071] This embodiment also provides a BeiDou navigation satellite signal ground-based monitoring system, including: a first module, used to obtain the ground-based system received power P by the signal power received by the ground-based receiving station. R (θ,φ); The second module is used to obtain the antenna pattern G based on the product information of the antenna of the preset ground-based monitoring station. R (θ,φ); The third module is used to obtain the transmission distance based on the location of the ground-based receiving station and the location of the BeiDou navigation satellites; the fourth module is used to determine the transmission distance based on the received power P of the ground-based system. R (θ,φ), Antenna pattern G R The equivalent isotropic radiated power of the BeiDou navigation satellite is obtained from (θ,φ) and transmission distance.

[0072] In the above embodiments, the received power of the ground system is obtained by the following formula:

[0073] P R (θ,φ)=S BC BDS ;

[0074] Among them, P R (θ,φ) represents the received power of the ground system, S B θ is the scale factor, φ is the elevation angle of the BeiDou navigation satellite, and C is the azimuth angle of the BeiDou navigation satellite. BDS This represents the power correlation value received by the ground-based receiver of the BeiDou navigation satellite signal.

[0075] In the above embodiments, the scale factor S B Obtained through a lookup table of low-noise amplifiers in the BeiDou power monitoring system.

[0076] In the above embodiments, the transmission distance is obtained by the following formula:

[0077]

[0078] Where R is the transmission distance, X T The X and Y coordinates of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system are... T The Y and Z coordinates of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system are... T The Z coordinate and X coordinate in the geocentric-ground-fixed coordinate system of the BeiDou navigation satellite are given. R The X and Y coordinates of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system are... R The Y-coordinate and Z-coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system are... R The Z-coordinate is the coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system.

[0079] In the above embodiments, the equivalent isotropic radiated power of the BeiDou navigation satellite is obtained by the following formula:

[0080]

[0081] Among them, E PRN (θ,φ) represents the equivalent isotropic radiated power of the BeiDou navigation satellite, G R (θ,φ) represents the antenna pattern, where θ is the elevation angle of the BeiDou navigation satellite, φ is the azimuth angle of the BeiDou navigation satellite, and C is a constant.

[0082] This invention obtains the transmission power and gain of each BeiDou navigation satellite under different incident directions by acquiring the equivalent omnidirectional radiation power of the BeiDou system, thereby overcoming the bottleneck problem of uncertainty in the power of the transmitter during quantitative remote sensing applications. Furthermore, this invention, through a ground-based monitoring system for BeiDou navigation satellite signals, enables all-weather, 24 / 7 ground-based monitoring of the BeiDou system's power. It not only obtains the final equivalent omnidirectional radiation power of the BeiDou system but also acquires effective information such as sudden power adjustments during BeiDou system operation, unique signal characteristics of the BeiDou system, ground-based atmospheric observation results, and high-precision point positioning with certain service capabilities.

[0083] This invention is specifically designed for my country's BeiDou system. The reflection power spectrum, transmitted signal properties, and navigation satellites to be monitored used in this invention are fundamentally different from those of other existing navigation satellite systems. This invention is simple, effective, and highly accurate, providing a reliable method for the application of BeiDou system reflection signals.

[0084] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A ground-based monitoring method for BeiDou navigation satellite signals, characterized in that... include: The received power of the ground system is obtained by the signal power received by the ground receiving station. The received power of the ground system is obtained by the power correlation value received by the ground receiving station and the scale factor calibration of the low noise amplifier lookup table. The antenna pattern is obtained based on the product information of the antenna of the pre-set ground-based monitoring station; The transmission distance is obtained based on the location of the ground-based receiving station and the location of the BeiDou navigation satellite; among them, the real-time transmission distance between the navigation satellite and the ground-based monitoring station is calculated based on the precise BeiDou ephemeris. The equivalent isotropic radiated power of the BeiDou navigation satellite is obtained based on the received power of the ground-based system, the antenna pattern, and the transmission distance. The received power of the ground system is obtained by the following formula: ； in, For the power received by the ground system, As a scale factor, The elevation angle of the BeiDou navigation satellite. The azimuth angle of the BeiDou navigation satellite. This represents the power-related value received by the ground-based receiving station; The satellite's geocentric and Earth-fixed coordinates are obtained through precise BeiDou ephemeris calculations, and the transmission distance is calculated using the following formula: ； in, For transmission distance, The X-coordinate of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system. The Y-coordinate of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system. The Z-coordinate of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system. The X-coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system. The Y-coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system. The Z-coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system; The equivalent isotropic radiated power of BeiDou navigation satellites is obtained using the following formula: ； in, This represents the equivalent isotropic radiated power of the BeiDou navigation satellite. Antenna radiation pattern, For the power received by the ground system, For transmission distance, The elevation angle of the BeiDou navigation satellite. The azimuth angle of the BeiDou navigation satellite. It is a constant.

2. The ground-based monitoring method for BeiDou navigation satellite signals according to claim 1, characterized in that: scale factor Obtained through a lookup table of low-noise amplifiers in the BeiDou power monitoring system.

3. A ground-based monitoring system for BeiDou navigation satellite signals, characterized in that... include: The first module is used to obtain the received power of the ground system through the signal power received by the ground receiving station. The received power of the ground system is obtained by calibrating the power correlation value received by the ground receiving station with the scale factor of the low noise amplifier lookup table. The second module is used to obtain the antenna pattern based on the product information of the antenna of the preset ground-based monitoring station; The third module is used to obtain the transmission distance based on the location of the ground-based receiving station and the location of the BeiDou navigation satellite; among which, the real-time transmission distance between the navigation satellite and the ground-based monitoring station is calculated based on the precise BeiDou ephemeris. The fourth module is used to obtain the equivalent isotropic radiated power of the BeiDou navigation satellite based on the received power of the ground system, the antenna pattern, and the transmission distance. The received power of the ground system is obtained by the following formula: ； in, For the power received by the ground system, As a scale factor, The elevation angle of the BeiDou navigation satellite. The azimuth angle of the BeiDou navigation satellite. This represents the power-related value received by the ground-based receiver; The satellite's geocentric and Earth-fixed coordinates are obtained through precise BeiDou ephemeris calculations, and the transmission distance is calculated using the following formula: ； in, For transmission distance, The X-coordinate of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system. The Y-coordinate of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system. The Z-coordinate of the BeiDou navigation satellite in the geocentric-ground-fixed coordinate system. The X-coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system. The Y-coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system. The Z-coordinate of the BeiDou power monitoring system in the geocentric-ground-fixed coordinate system; The equivalent isotropic radiated power of BeiDou navigation satellites is obtained using the following formula: ； in, This represents the equivalent isotropic radiated power of the BeiDou navigation satellite. For the power received by the ground system, For transmission distance, Antenna radiation pattern, The elevation angle of the BeiDou navigation satellite. The azimuth angle of the BeiDou navigation satellite. It is a constant.

4. The BeiDou navigation satellite signal ground-based monitoring system according to claim 3, characterized in that: scale factor Obtained through a lookup table of low-noise amplifiers in the BeiDou power monitoring system.

Images