A GNSS interference detection method and system based on AGC gain of a space-borne GNSS occultation probe

Abstract

The application provides a GNSS interference detection method and system based on AGC gain of a spaceborne GNSS occultation detector, the method comprising: reading AGC gain data and LEO satellite position data; time matching the AGC gain data and the LEO satellite position data; determining AGC gain under a condition without GNSS interference; calculating an AGC gain difference sequence; and performing GNSS interference detection on the AGC gain difference sequence based on a set GNSS interference detection threshold. The application has the advantages that it is suitable for a spaceborne GNSS occultation detector, and provides an effective solution for GNSS interference detection based on observation of the spaceborne GNSS occultation detector, which is simple, effective and easy to implement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical and application fields of GNSS remote sensing and GNSS interference monitoring, and particularly relates to a GNSS interference detection method and system based on AGC gain of a spaceborne GNSS occultation detector. BACKGROUND

[0002] Global Navigation Satellite System (GNSS) has greatly promoted the development of the economic society, promoted the progress of scientific research, helped the construction of national defense army, and changed the way of people's life. With the rapid development and wide application of GNSS, the natural vulnerability of GNSS has been exposed, and intentional or unintentional GNSS interference has also increased, especially the emergence of intentional GNSS interference, which has greatly endangered the safety of GNSS-based applications and systems. Therefore, GNSS interference monitoring technology and application has become one of the current research focuses.

[0003] Space-based GNSS occultation remote sensing detection technology is a technology based on remote sensing detection of the earth's atmosphere by GNSS. The spaceborne GNSS occultation detector is an effective payload for space-based GNSS occultation remote sensing detection, which is usually carried on a low earth orbit (LEO) satellite. It is worth mentioning that the occultation antenna equipped by the spaceborne GNSS occultation detector is a right-hand circularly polarized high-gain antenna, which can receive GNSS occultation signals from the earth's surface as well as GNSS interference. These received GNSS interference will inevitably affect the normal work of the spaceborne GNSS occultation detector and affect the measurement values of various observations.

[0004] In summary, GNSS interference detection based on spaceborne GNSS occultation detector observations has been one of the research hotspots. SUMMARY

[0005] The purpose of the present application is to provide a GNSS interference detection method based on AGC gain of a spaceborne GNSS occultation detector. The method can be applied to the spaceborne GNSS occultation detector, and provides an effective solution for GNSS interference detection based on spaceborne GNSS occultation detector observations.

[0006] In order to achieve the above purpose, the present application provides a GNSS interference detection method based on AGC gain of a spaceborne GNSS occultation detector, which comprises:

[0007] Step S101) reading AGC gain data;

[0008] Step S102) reading LEO satellite position data;

[0009] Step S103) time matching AGC gain data and LEO satellite position data;

[0010] Step S104) determining AGC gain under no GNSS interference condition;

[0011] Step S105) calculating AGC gain difference sequence;

[0012] Step S106) GNSS interference detection on AGC gain difference sequence based on set GNSS interference detection threshold.

[0013] As an improvement of the above method, the step S104) comprises:

[0014] Taking the South Pacific region as the no GNSS interference region, all LEO satellite positions in the South Pacific region form a set {P s}, the set {P s} satisfies:

[0015]

[0016] Wherein, i represents the serial number of LEO satellite position sequence; P(i) represents the i-th element in LEO satellite position sequence P; the mathematical symbol represents any; Lon represents longitude; Lat represents latitude;

[0017] The AGC gain corresponding to the set {P s} forms a set {G s} ; the AGC gain under no GNSS interference condition is represented as:

[0018] G0=mean({G s})

[0019] Wherein, G0represents the AGC gain under no GNSS interference condition; mean(·) represents the function of taking the average value of all elements.

[0020] As an improvement of the above method, the step S105) comprises:

[0021] Based on the AGC gain sequence G and the AGC gain G0under no GNSS interference condition, the AGC gain difference sequence is calculated, represented as:

[0022] ΔG=[ΔG(1), ΔG(2), ΔG(3), …, ΔG(n), …, ΔG(N)]

[0023] Wherein, AG represents AGC gain difference sequence; AG(n) represents the nth element in AGC gain difference sequence, AG(n)=G(n)-G0.

[0024] As an improvement of the above method, the step S106) comprises:

[0025] Based on AGC gain difference sequence AG, when AG(n)≤Th, it is determined that LEO satellite receives GNSS interference at position P(n); when AG(n)>Th / 2, it is determined that LEO satellite does not receive GNSS interference at position P(n); when Th<AG(n)≤Th / 2, it is determined that LEO satellite is suspected to receive GNSS interference at position P(n); Th represents a set GNSS interference detection threshold.

[0026] The application also provides a GNSS interference detection system based on AGC gain of space-borne GNSS occultation probe, which is realized based on the above method, and the system comprises:

[0027] The reading gain data module is used for reading AGC gain data;

[0028] The reading satellite position data module is used for reading LEO satellite position data;

[0029] The time matching module is used for time matching AGC gain data and LEO satellite position data;

[0030] The determining non-interference gain module is used for determining AGC gain under non-GNSS interference condition;

[0031] The calculating gain difference sequence module is used for calculating AGC gain difference sequence;

[0032] The interference detection module is used for GNSS interference detection of AGC gain difference sequence according to a set GNSS interference detection threshold.

[0033] Compared with the prior art, the application has the following advantages:

[0034] 1. The method provided by the application is suitable for space-borne GNSS occultation probe, and provides an effective solution for GNSS interference detection based on observation of space-borne GNSS occultation probe;

[0035] 2. The method provided by the application is simple and effective, and is easy to realize. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The figure shows a flow chart of GNSS interference detection method based on AGC gain of space-borne GNSS occultation probe. DETAILED DESCRIPTION

[0037] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings.

[0038] As shown in Figure 1 The present application proposes a GNSS interference detection method based on AGC gain of a spaceborne GNSS occultation sounder, comprising:

[0039] Step S101) reading AGC gain data;

[0040] Generally, the radio frequency unit equipped in the spaceborne GNSS occultation sounder contains an AGC module, which is used to adjust the gain of the radio frequency front end autonomously, so as to ensure that the strength of the signal input to the subsequent ADC is in a suitable interval, and then ensure the normal work of the spaceborne GNSS occultation sounder. The gain of the AGC module contained in the radio frequency unit is called AGC gain. The spaceborne GNSS occultation sounder host reads the AGC gain in real time at a certain frequency. G(t) represents the real-time read AGC gain, with the unit of "dB"; wherein, t represents time, with the unit of "second".

[0041] Step S102) reading LEO satellite position data;

[0042] The spaceborne GNSS occultation sounder usually contains a spaceborne GNSS receiver module. The spaceborne GNSS receiver module is responsible for processing GNSS signals and positioning solution, so as to obtain the position information of the LEO satellite platform where the spaceborne GNSS occultation sounder is located. The spaceborne GNSS occultation sounder host reads the LEO satellite position information in real time at a certain frequency. P(t) represents the real-time read LEO satellite position information.

[0043] Step S103) time matching of AGC gain data and LEO satellite position data;

[0044] Based on the real-time read AGC gain G(t) and the real-time read LEO satellite position P(t), the AGC gain data and the LEO satellite position data matching operation is performed. The matching operation will correspond the AGC gain and the LEO satellite position read at the same time one by one, and respectively obtain the AGC gain sequence and the LEO satellite position sequence.

[0045] The one-to-one corresponding AGC gain sequence and LEO satellite position sequence are represented as:

[0046]

[0047] wherein G represents the AGC gain sequence; P represents the LEO satellite position sequence; n represents the sequence number; N represents the total number of elements; G(n) represents the nth element in the AGC gain sequence; P(n) represents the nth element in the LEO satellite position sequence, and P(n) = [Lon(n), Lat(n), Alt(n)] T ; wherein Lon represents the longitude, Lat represents the latitude, and Alt represents the altitude. The superscript T represents the transpose.

[0048] Step S104) determining the AGC gain under the condition of no GNSS interference;

[0049] Generally, the South Pacific region (west longitude 170° to west longitude 90°, south latitude 60° to south latitude 10°) is far away from the mainland, sparsely populated, and GNSS interference rarely occurs. Therefore, the South Pacific region is regarded as a GNSS interference-free region. The LEO satellite position set {P s} consisting of all the subsatellite points in the South Pacific region is obtained, and the set {P s} satisfies:

[0050]

[0051] wherein i represents the sequence number of the LEO satellite position sequence, and P(i) represents the ith element in the LEO satellite position sequence P; the mathematical symbol represents any.

[0052] The AGC gain set {G s} corresponding to the set {P s} is obtained. The AGC gain under the condition of no GNSS interference is represented as:

[0053] G0 = mean({G s}) (3)

[0054] wherein G0 represents the AGC gain under the condition of no GNSS interference; mean(-) represents the function of taking the average value of all elements.

[0055] Step S105) calculating the AGC gain difference sequence;

[0056] Based on the AGC gain sequence G and the AGC gain G0 under the condition of no GNSS interference, the AGC gain difference sequence is calculated, represented as:

[0057] ΔG = G - G0 = [ΔG(1), ΔG(2), ΔG(3), …, ΔG(n), …, ΔG(N)] (4)

[0058] Wherein, AG represents AGC gain difference sequence; AG(n) represents the nth element in AGC gain difference sequence, and AG(n)=G(n)-G0.

[0059] Step S106) GNSS interference detection;

[0060] Based on AGC gain difference sequence AG, when AG(n)≤Th, it is determined that LEO satellite receives GNSS interference at position P(n); when AG(n)>Th / 2, it is determined that LEO satellite does not receive GNSS interference at position P(n); when Th<AG(n)≤Th / 2, it is determined that LEO satellite is suspected to receive GNSS interference at position P(n). Th represents GNSS interference detection threshold, which is generally an empirical value, with unit "dB".

[0061] The application also provides a GNSS interference detection system based on AGC gain of satellite-borne GNSS occultation probe, which is realized based on the above method, and the system comprises:

[0062] A gain data reading module is configured to read AGC gain data;

[0063] A satellite position data reading module is configured to read LEO satellite position data;

[0064] A time matching module is configured to time match AGC gain data and LEO satellite position data;

[0065] A non-interference gain determining module is configured to determine AGC gain under non-GNSS interference condition;

[0066] A gain difference sequence calculating module is configured to calculate AGC gain difference sequence;

[0067] An interference detection module is configured to perform GNSS interference detection on AGC gain difference sequence according to a set GNSS interference detection threshold.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the application rather than limit the application. Although the application is described in detail with reference to the embodiments, those skilled in the art should understand that the technical solutions of the application can be modified or replaced equivalently without departing from the spirit and scope of the application, and all of them should be covered in the scope of the claims of the application.

Claims

1. A GNSS interference detection method based on the AGC gain of a spaceborne GNSS occultation detector, comprising: Step S101) Read AGC gain data; Step S102) Read LEO satellite position data; Step S103) Time matching is performed between the AGC gain data and the LEO satellite position data; Step S104) Determine the AGC gain under conditions without GNSS interference; Step S105) Calculate the AGC gain difference sequence; Step S106) Perform GNSS interference detection on the AGC gain difference sequence based on the set GNSS interference detection threshold.

2. The GNSS interference detection method based on the AGC gain of a spaceborne GNSS occultation detector according to claim 1, characterized in that, Step S104) includes: The South Pacific region is considered a GNSS-free area, and all LEO satellite positions located in the South Pacific region are grouped into a set {P}. s }, set {P s }satisfy: Where i represents the ordinal number of the LEO satellite position sequence; P(i) represents the i-th element in the LEO satellite position sequence P; mathematical symbols Lon indicates any; Lat indicates latitude. With set {P s The corresponding AGC gain set {G} s The AGC gain under conditions without GNSS interference is expressed as: G0=mean({G s }) Where G0 represents the AGC gain under conditions without GNSS interference; mean(·) represents the function of averaging all elements.

3. The GNSS interference detection method based on the AGC gain of a spaceborne GNSS occultation detector according to claim 1, characterized in that, Step S105 includes: Based on the AGC gain sequence G and the AGC gain G0 under GNSS interference-free conditions, the AGC gain difference sequence is calculated and expressed as follows: ΔG=[ΔG(1),ΔG(2),ΔG(3),…,ΔG(n),…,ΔG(N)] Where ΔG represents the AGC gain difference sequence; ΔG(n) represents the nth element in the AGC gain difference sequence, ΔG(n) = G(n) - G0.

4. The GNSS interference detection method based on the AGC gain of a spaceborne GNSS occultation detector according to claim 1, characterized in that, Step S106) includes: Based on the AGC gain difference sequence ΔG, when ΔG(n)≤Th, it is determined that the LEO satellite received GNSS interference at position P(n); when ΔG(n)>Th / 2, it is determined that the LEO satellite did not receive GNSS interference at position P(n); when Th<ΔG(n)≤Th / 2, it is determined that the LEO satellite is suspected of receiving GNSS interference at position P(n); Th represents the set GNSS interference detection threshold.

5. A GNSS interference detection system based on the AGC gain of a spaceborne GNSS occultation detector, implemented according to the method described in any one of claims 1-4, characterized in that, The system includes: The gain data reading module is used to read AGC gain data; The satellite position data reading module is used to read LEO satellite position data; The time matching module is used to time match AGC gain data with LEO satellite position data; The interference-free gain module is used to determine the AGC gain under conditions of no GNSS interference. The module for calculating the gain difference sequence is used to calculate the AGC gain difference sequence; and The interference detection module is used to perform GNSS interference detection on the AGC gain difference sequence according to the set GNSS interference detection threshold.

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