CN114679231B - Method for acquiring space-based radio frequency map - Google Patents

Abstract

The invention discloses a method for acquiring a space-based radio frequency map, which comprises the following steps of S1, acquiring radial distances between a satellite and a radiation source at different moments based on position coordinates of a ground radiation source; s2, acquiring signal power samples of the ground radiation source at a plurality of points of a space orbit by the satellite based on the radial distance between the satellite and the radiation source; s3, acquiring average emission power of a radiation source based on signal power sampling; s4, acquiring the power density around the radiation source by using the average emission power of the radiation source based on the electromagnetic wave prediction model of the mobile communication base station; and S5, synthesizing the related data to obtain a space-based radio frequency map. The advantages are that: the acquired space-based radio frequency map is wide in coverage range, long in working duration, strong in concealment and good in safety.

Description

A method of obtaining space-based radio frequency map

technical field

The invention relates to the technical field of radio frequency maps, in particular to a method for acquiring space-based radio frequency maps.

Background technique

Radio frequency maps provide stakeholders with a tool to visualize current and potential spectrum interference and usage, enabling more effective spectrum management. The radio frequency map can visually display the spectrum usage, help spectrum managers detect unused spectrum, quickly allocate it to other needs, and improve task efficiency.

Many scholars at home and abroad have carried out research on this. Some scholars have done perception experiments in the actual environment, as shown in Figure 1: the left picture is the sensor deployment point map, and the right picture is the radio frequency map obtained by interpolation. The advantage of this scheme is that when there are a large number of sensors scattered and the coverage is wide and uniform enough, a fine regional radio frequency map will be obtained. The disadvantages are limited coverage and duration, difficulty in uniform perception, poor concealment and security, once the sensor link The perception results cannot be uploaded due to interference, and the performance of the entire system decreases or even fails. Some scholars have improved the radio frequency map interpolation algorithm to improve the accuracy of the radio frequency map, but these research results are based on foreign sensor throwing schemes.

ZL201210379047.4 calculates the surrounding electromagnetic situation from the perspective of the aircraft, but he ignores the spatial location information of the electromagnetic radiation source. Strictly speaking, what is perceived is not a map of radiation sources, but a map similar to the distribution of electromagnetic field strength. Both ZL201310372841.0 and ZL201610235479.6 estimate the surrounding electromagnetic situation from the perspective of a single-point monitoring station, and also ignore the radiation source location information, and do not constitute a radiation source map. ZL201710979669.3 mainly optimizes the deployment of sensors. ZL201810939989.0 uses the spatial resolution capability of the array antenna to locate the radiation source and invert the electromagnetic situation, but the spatial resolution of the array antenna decreases significantly with the increase of the distance, which is a small-scale and non-uniform perception method. It is not much different from other single-point perception systems when it comes to large-scale perception from a long distance.

To sum up, the existing radio frequency map technology has the following disadvantages:

1. The coverage area is small; whether it is multi-sensor throwing or single-point monitoring, it is impossible to locate and perceive radiation sources in a wide range to form a radio frequency map.

2. The working duration is limited; the sensing sensor needs to process and upload the sensing results in real time, and the built-in battery cannot work for a long time.

3. Difficulty in uniform sensing; affected by meteorological and environmental factors at the time of throwing, it is difficult for the scattered sensors to be evenly distributed in the area to be sensed. Even if the spatial positions can be evenly distributed, the perceptual sampling is non-uniform due to occlusions such as terrain and buildings.

4. Poor concealment.

5. Poor security.

To sum up, the current radio frequency map acquisition methods are mainly based on fixed sensors (single-point or multi-point), some focus on the electromagnetic feature processing of single-point observations of sensors, and some focus on the electromagnetic environment of multi-sensors For inversion and visualization work, there is currently no method to obtain radio frequency maps in a large-scale, uniform, covert, and safe manner.

Contents of the invention

The purpose of the present invention is to provide a method for acquiring space-based radio frequency maps, so as to solve the aforementioned problems in the prior art.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows:

A method for obtaining a space-based radio frequency map, comprising the steps of,

S1. Obtain the radial distance between the satellite and the radiation source at different times based on the position coordinates of the ground radiation source;

S2. Based on the radial distance between the satellite and the radiation source, obtain the signal power sampling of the ground radiation source by the satellite at several points in the space orbit;

S3. Obtain the average transmit power of the radiation source based on signal power sampling;

S4. Based on the electromagnetic wave prediction model of the mobile communication base station, the power density around the radiation source is obtained by using the average transmission power of the radiation source;

S5. Obtain a space-based radio frequency map by synthesizing the above relevant data.

Preferably, in step S3, the satellite samples the signal power of the ground radiation source at several points in the space orbit as,

Among them, P _i is the signal power of the satellite at the space orbit point i to the ground radiation source; P _tr is the transmission power of the ground radiation source; G _i is the ground radiation when the satellite is at (X _i , Y _i , _Zi ). The equivalent antenna gain of the source in the line-of-sight direction of the main lobe of the satellite antenna; L _i is the equivalent attenuation value of the signal space propagation from the ground radiation source to the satellite when the satellite is located at (X _i , Y _i , _Zi ); R _i is the radial distance between the satellite at orbit point i and the radiation source.

Preferably, step S4 specifically includes the following content,

通过针对不同环境下的不同辐射源进行地面定标，构建辐射源标定先验数据库；根据辐射源的类型在数据库中搜索匹配的辐射源参数

S41. On-the-spot measurement of the transmission power of a certain ground radiation source to obtain P _tr , based on sampling P _i of the signal power of the ground radiation source at several points in the space orbit by the satellite, and calculating the parameters of the ground radiation source when the satellite line-of-sight is R _i

Through ground calibration for different radiation sources in different environments, construct a radiation source calibration prior database; search for matching radiation source parameters in the database according to the type of radiation source

即可获取地面辐射源平均发射功率。S42. Carry out fusion processing on the radiation source received signal power samples at N points on the satellite orbit, and combine the radiation source parameters

The average transmit power of the ground radiation source can be obtained.

代入到下式中，获取辐射源平均发射功率

Preferably, step S42 obtains the average emission power of the ground radiation source by means of average fusion, specifically, the radiation source parameters

Substitute into the following formula to obtain the average emission power of the radiation source

Wherein, N is the total number of spatial sampling points, i=1, 2, 3,...,N.

Preferably, step S5 is specifically, based on the mobile communication base station electromagnetic wave prediction model, when only considering the antenna main lobe axial linear electromagnetic radiation intensity, obtain the peripheral power density of the radiation source;

Among them, P _d is the power density around the radiation source; G _tr is the antenna gain of the radiation source; L is the wireless propagation loss; r is the distance between the ground radiation source and the measured point.

The beneficial effects of the present invention are: 1. The obtained space-based radio frequency map covers a wide range. 2. The obtained space-based radio frequency map lasts for a long time. 3. Since the radiation source is viewed from the zenith, the signal is a direct wave signal, and the scattering and multipath effects caused by the terrain environment are averaged, so that the perception of the space-based radio frequency map is uniform. 4. The obtained space-based radio frequency map is highly concealed and can be transmitted to any safe place through satellite-ground or inter-satellite links. 5. The obtained space-based radio frequency map is safe.

Description of drawings

FIG. 1 is a sensor deployment diagram and a radio frequency map obtained by interpolation in the prior art;

Fig. 2 is a schematic flow chart of the method in the embodiment of the present invention;

Fig. 3 is a schematic diagram of obtaining the radial distance between the satellite and the radiation source using the precise ephemeris provided by the ground measurement and control station in an embodiment of the present invention;

Fig. 4 is a map around the opponent's base in the embodiment of the present invention;

Fig. 5 is a schematic diagram of the electromagnetic radiation power density of the estimated radiation source and its surroundings in the embodiment of the present invention;

Fig. 6 is a space-based radio frequency map obtained based on single-satellite Doppler frequency difference passive positioning obtained in an embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the present invention, and are not intended to limit the present invention.

Embodiment one

As shown in Figure 2, in this embodiment, a method for obtaining a space-based radio frequency map is provided, including the following steps,

S1. Obtain the radial distance between the satellite and the radiation source at different times based on the position coordinates of the ground radiation source;

S2. Based on the radial distance between the satellite and the radiation source, obtain the signal power sampling of the ground radiation source by the satellite at several points in the space orbit;

S3. Obtain the average transmit power of the radiation source based on signal power sampling;

S4. Based on the electromagnetic wave prediction model of the mobile communication base station, the power density around the radiation source is obtained by using the average transmission power of the radiation source;

S5. Obtain a space-based radio frequency map by synthesizing the above relevant data.

In this embodiment, there are many ways to obtain the position coordinates of the ground radiation source. In this embodiment, the single-satellite Doppler frequency difference passive positioning model is used to obtain the acquisition. This method obtains rough position coordinates, and the positioning error On the order of hundreds of meters.

In this embodiment, as shown in Figure 3, step S1 is specifically, according to the position coordinates of the ground radiation source, combined with the precise ephemeris provided by the ground measurement and control station, to obtain the radial distance R _i between the satellite and the radiation source , the calculation formula is,

Among them, (x, y, z) are the position coordinates of the ground radiation source; (X _i , Y _i , _Zi ) are the precise ephemeris provided by the ground measurement and control station.

After obtaining the radial distance between the satellite and the radiation source at different times, the signal strength S _i received by the satellite at the spatial position (Xi, Yi, Zi) can be obtained by the following formula,

In this embodiment, in step S3, the satellite samples the signal power of the ground radiation source at several points in the space orbit as follows:

...

Among them, P _i is the signal power of the satellite at the space orbit point i to the ground radiation source; P _tr is the transmission power of the ground radiation source; G _i is the ground radiation when the satellite is at (X _i , Y _i , _Zi ). The equivalent antenna gain of the source in the line-of-sight direction of the main lobe of the satellite antenna (because the movement of the satellite causes the angle between the orientation of the ground radiation source antenna and the central axis of the main lobe of the satellite antenna to change with time, so G _i also changes with time and is related to satellite position); similarly, L _i is the equivalent attenuation value of the signal space propagation from the ground radiation source to the satellite when the satellite is located at (X _i , Y _i , _Zi ), this value is related to the atmosphere, space environment parameters and related to the satellite position.

In this embodiment, step S4 specifically includes the following content,

通过针对不同环境下的不同辐射源进行地面定标，构建辐射源标定先验数据库；根据辐射源的类型在数据库中搜索匹配的辐射源参数

S41. On-the-spot measurement of the transmission power of a certain ground radiation source to obtain P _tr , based on sampling P _i of the signal power of the ground radiation source at several points in the space orbit by the satellite, and calculating the parameters of the ground radiation source when the satellite line-of-sight is R _i

Through ground calibration for different radiation sources in different environments, construct a radiation source calibration prior database; search for matching radiation source parameters in the database according to the type of radiation source

通过针对城市、郊区、山区、森林、丘陵等不同环境下的不同辐射源(基站、电台、雷达、干扰机等)进行地面定标，可构建辐射源标定先验数据库。在实际应用时，可根据辐射源类型在数据库中搜索相匹配的辐射源参数

代入相应公式中，即可求得

That is to say, G _i and L _i can be obtained by means of ground calibration with various typical ground radiation sources. Specifically, the transmit power of a mobile phone base station in a certain place is measured on the spot to obtain P _tr , and then based on the satellite space multi-point observation value P _{i ,} the specific parameters of the ground radiation source antenna (antenna type, orientation, gain, polarization mode, frequency range, lobe width, standing wave ratio, etc.)

Through ground calibration for different radiation sources (base stations, radio stations, radars, jammers, etc.) in different environments such as cities, suburbs, mountains, forests, and hills, a priori database for radiation source calibration can be constructed. In actual application, the matching radiation source parameters can be searched in the database according to the type of radiation source

Substituting into the corresponding formula, we can get

值，从而实现对辐射源平均发射功率的精确估计。That is, the types of radiation sources detected by other means and the characteristics of the surrounding environment are retrieved in the radiation source calibration prior database.

value, so as to achieve an accurate estimate of the average emission power of the radiation source.

即可获取地面辐射源平均发射功率。S42. Carry out fusion processing on the radiation source received signal power samples at N points on the satellite orbit, and combine the radiation source parameters

The average transmit power of the ground radiation source can be obtained.

代入到下式中，获取辐射源平均发射功率

There are many methods of fusion processing in step S42, including but not limited to kalman filter, least square method, average fusion, etc. In step S42, average fusion is specifically used for fusion processing, and then the average transmission power of the ground radiation source is obtained. The specific operation process is to set the radiation source parameters

Substitute into the following formula to obtain the average emission power of the radiation source

Wherein, N is the total number of spatial sampling points, i=1, 2, 3,...,N.

In this embodiment, step S5 is specifically, based on the electromagnetic wave prediction model of the mobile communication base station in the standard HJ/T10.2-1996 "Radiation Environmental Protection Management Guidelines - Electromagnetic Radiation Monitoring Instruments and Methods", when only the main lobe of the antenna is considered When the axial linear electromagnetic radiation intensity is measured, the power density around the radiation source is obtained;

Among them, P _d is the power density around the radiation source; G _tr is the antenna gain of the radiation source; L is the wireless propagation loss, which can be based on Okumura-Hata, COST231-Hata, COST231 Walfisch-Ikegami, Keenan-Motley and other models, combined with the sensing area GIS environmental information and signal parameter characteristics are obtained; r is the distance between the ground radiation source and the measured point.

Combining with the relevant parameters obtained in the above process, the space-based radio frequency map is finally obtained.

Embodiment two

In this embodiment, taking the surrounding scene of the other party's base as an example, the feasibility of the method for obtaining a space-based radio frequency map (Radio Map, RM) is simulated and analyzed.

The surrounding map of the opponent's base is shown in Figure 4. Through GIS scale measurement, the map accuracy is estimated to be 28.76m (pixel interval). Due to the lack of actual data, it is now assumed that there are radiation sources in the opponent's base and its surrounding cities and villages, and their positions are obtained through single-satellite Doppler frequency difference passive positioning technology.

Based on the estimation of the average emission power of the radiation source on the multi-point sampling of a single satellite in orbit, and then using the electromagnetic wave prediction model in the standard HJ/T10.2-1996 and the surrounding GIS information, the electromagnetic radiation power density (unit: dBm) of the radiation source and its surroundings is estimated ), as shown in Figure 5: Finally, a space-based radio frequency map (RM) based on single-satellite Doppler frequency difference passive positioning is obtained, and the effect is shown in Figure 6.

The RM information can be combined with time, frequency, space, signal type and other information to form a dynamic radio frequency map.

By adopting the above-mentioned technical scheme disclosed by the present invention, the following beneficial effects are obtained:

The invention provides a method for acquiring a space-based radio frequency map, and the space-based radio frequency map acquired by the method covers a wide range. Acquired space-based radio frequency maps work for long durations. Since the radiation source is viewed from the zenith, the signal is a direct wave signal, and the scattering and multipath effects caused by the terrain environment are averaged, so that the perception of the space-based radio frequency map is uniform. The obtained space-based radio frequency map is highly concealed and can be transmitted to any safe place through satellite-ground or inter-satellite links. The obtained space-based radio frequency map has good security.

The above is only a preferred embodiment of the present invention, and it should be pointed out that for those of ordinary skill in the art, some improvements and modifications can be made without departing from the principle of the present invention. It should be regarded as the protection scope of the present invention.

Claims (2)

1. A method for obtaining a space-based radio frequency map, characterized in that: comprising the steps, S1. Obtain the radial distance between the satellite and the ground radiation source at different times based on the position coordinates of the ground radiation source; S2. Based on the radial distance between the satellite and the ground radiation source, obtain the signal power sampling of the ground radiation source by the satellite at several points in the space orbit; S3. Obtain the average transmission power of the ground radiation source based on signal power sampling; in step S3, the satellite samples the signal power of the ground radiation source at several points in the space orbit as,

Among them, P _i is the signal power of the satellite at the space orbit point i to the ground radiation source; P _tr is the transmission power of the ground radiation source; G _i is the ground radiation when the satellite is at (X _i , Y _i , _Zi ). The equivalent antenna gain of the source in the line-of-sight direction of the main lobe of the satellite antenna; L _i is the equivalent attenuation value of the signal space propagation from the ground radiation source to the satellite when the satellite is located at (X _i , Y _i , _Zi ); R _i is the radial distance between the satellite at space orbit point i and the ground radiation source, that is, the satellite line-of-sight; S4. Based on the electromagnetic wave prediction model of the mobile communication base station, the average transmission power of the radiation source is used to obtain the surrounding power density of the radiation source; step S4 specifically includes the following content, S41. On-the-spot measurement of the transmission power of a certain ground radiation source to obtain P _tr , based on sampling P _i of the signal power of the ground radiation source at several points in the space orbit by the satellite, and calculating the parameters of the ground radiation source when the satellite line-of-sight is R _i

By performing ground calibration for different ground radiation sources in different environments, construct a ground radiation source calibration prior database; search for matching ground radiation source parameters in the database according to the type of ground radiation source

S42. Carry out fusion processing on the signal power sampling of the ground radiation source at point N of the satellite on the space orbit, and combine the parameters of the ground radiation source

The average transmit power of the ground radiation source can be obtained; Step S42 adopts the average fusion method to obtain the average transmission power of the ground radiation source, specifically, the parameters of the ground radiation source

Substitute into the following formula to obtain the average transmit power of the ground radiation source

Among them, N is the total number of spatial sampling points, i=1,2,3,...,N; S5. Based on the average transmission power of the ground radiation source obtained above, and based on the mobile communication base station electromagnetic wave prediction model, the power density around the ground radiation source is obtained, and then the space-based radio frequency map is obtained. 2. The method for obtaining a space-based radio frequency map according to claim 1, characterized in that: step S5 is specifically, based on the mobile communication base station electromagnetic wave prediction model, when only considering the antenna main lobe axial linear electromagnetic radiation intensity, obtain the ground Power density around the radiation source;

Among them, P _d is the power density around the ground radiation source; G _tr is the antenna gain of the ground radiation source; L is the wireless propagation loss; r is the distance between the ground radiation source and the measured point.

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