GNSS navigation signal coexistence test system and sensitive threshold evaluation method

Abstract

The invention discloses a GNSS (Global Navigation Satellite System) navigation signal coexistence test system and a sensitive threshold evaluation method, and relates to the technical field of electromagnetic compatibility test, and the GNSS navigation signal coexistence test system comprises an electric wave reverberation chamber, a GNSS navigation signal transponder, a GNSS navigation signal receiver and an upper computer, the electric wave reverberation chamber comprises a mechanical stirrer, a radio frequency signal source, a radio frequency power amplifier, a frequency spectrograph, a transmitting antenna T and a receiving antenna R, the GNSS navigation signal transponder comprises a forwarding terminal, a forwarding receiving antenna TR and a forwarding transmitting antenna TT, and the GNSS navigation signal receiver comprises a receiving terminal and a receiving antenna RR; the multi-path scattering characteristic of the electric wave reverberation chamber is utilized to simulate the fading characteristic of a wireless signal in a real environment, and the high quality factor of the electric wave reverberation chamber is utilized to form a high-level test environment within a broadband range by utilizing relatively small input power, so that a GNSS navigation signal coexistence test and quantitative evaluation analysis on a sensitive threshold are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic compatibility testing, and in particular to a GNSS navigation signal coexistence testing system and a sensitivity threshold evaluation method. Background Art

[0002] The Global Satellite Navigation System (GNSS) is widely used in low-altitude economic fields such as general aviation manned flight, unmanned logistics, unmanned inspection, unmanned detection, unmanned mapping and unmanned remote sensing.

[0003] However, with the widespread application of high-power frequency-consuming electronic equipment or systems such as wireless communication base stations, portable mobile terminals, new phased array radars, high-speed frequency-hopping radios, and electronic countermeasure jammers, the problem of anti-interference coexistence of multiple wireless signals has become prominent, causing a series of wireless communication quality problems such as large transmission delay and high bit error rate.

[0004] In the existing technology, GNSS navigation signal coexistence testing and sensitivity threshold evaluation are mainly carried out in plane wave test environments such as radio darkrooms or simulated open fields. First, the testing and evaluation process needs to simulate the multipath effect of wireless signals in real environments. There is a large deviation between the simulation results in radio darkrooms or simulated open fields and the statistical characteristics of the actual environment. Second, due to the limitations of test instruments such as antennas and power amplifiers, the test voltage levels that can be generated in radio darkrooms or simulated open fields are limited, making it difficult to evaluate the coexistence performance, anti-interference margin and sensitivity threshold of GNSS navigation signals. Finally, the existing standards mainly test narrowband and cannot reflect the coexistence capability of GNSS navigation signals in 100MHz-18GHz broadband conditions.

[0005] Therefore, a GNSS navigation signal coexistence test system and a sensitivity threshold evaluation method are provided to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a GNSS navigation signal coexistence test system and a sensitivity threshold evaluation method, which simulate the fading characteristics of wireless signals in a real environment, improve the evaluation accuracy of the anti-interference coexistence capability of GNSS navigation signals under multipath effects, form a high-level test environment within a wide frequency band, and provide theoretical and experimental method support for evaluating the sensitivity threshold that affects the coexistence of GNSS navigation signals.

[0007] To achieve the above objectives, the present invention provides a GNSS navigation signal coexistence test system, including a radio wave reverberation chamber, a GNSS navigation signal repeater, a GNSS navigation signal receiver and a host computer. The radio wave reverberation chamber includes a mechanical stirrer, a radio frequency signal source, a radio frequency power amplifier, a spectrum analyzer, a transmitting antenna T and a receiving antenna R. The GNSS navigation signal repeater includes a forwarding terminal, a forwarding receiving antenna TR and a forwarding transmitting antenna TT. The GNSS navigation signal receiver includes a receiving terminal and a receiving antenna RR.

[0008] Preferably, the RF signal source and the RF power amplifier are connected through an RF coaxial cable, the RF power amplifier and the transmitting antenna T are connected through a cable, the spectrum analyzer and the receiving antenna R are connected through a cable, the forwarding terminal and the forwarding receiving antenna TR are connected through a cable, the forwarding terminal and the forwarding transmitting antenna TT are connected through a cable, the host computer and the receiving terminal are connected through a cable, and the receiving terminal and the receiving antenna RR are connected through a cable.

[0009] Preferably, the forwarding terminal, the forwarding receiving antenna TR and the host computer are all arranged outside the radio wave reverberation chamber, the host computer is set as a computer PC, a monitoring unit is provided inside the computer PC, the forwarding transmitting antenna TT, the receiving terminal and the receiving antenna RR are all arranged inside the radio wave reverberation chamber, and the distance between the receiving terminal and the metal wall surface, and the distance between the receiving antenna RR and the metal wall surface are not less than one-quarter wavelength of the test frequency.

[0010] A sensitivity threshold evaluation method for a GNSS navigation signal coexistence test system includes the following steps: S1: Configure the internal experimental environment of the radio reverberation chamber to determine the test frequency range of the GNSS navigation signal receiver to be tested Frequency intervals and test levels E p , change the position of the mechanical stirrer j Set to j =0; S2: Mechanical stirrer steps to position j = j +1 for a given frequency , injected input power , forming the test level E p ; S3: For a given frequency , according to the three-dimensional coordinates, determine the desired test level E p Under the coexistence capability of GNSS navigation signals, if GNSS navigation signals coexist, record the coexistence with input power. The corresponding peak field strength and peak received power ; S4: If there are coexistence issues with GNSS navigation signals, adjust the input power , so that GNSS navigation signals coexist, record and input power The corresponding peak field strength and peak received power ; S5: Determine the position of the mechanical stirrer j and set position number N If the relationship between the position of the mechanical stirrer j Not more than the set position number N , repeat steps S1 to S4; S6: If the position of the mechanical stirrer j Greater than the set position number N， For any frequency , record separately N Test level corresponding to the coexistence of two GNSS navigation signals E p , extract the test level E p The minimum value of the frequency Sensitive threshold for coexistence of GNSS navigation signals.

[0011] Preferably, in step S1, the test level E p Set to the maximum field strength expected for coexistence of GNSS navigation signals in a real environment.

[0012] Preferably, in step S1, configuring the internal experimental environment of the radio wave reverberation chamber specifically includes the following steps: S11: Place the forwarding transmitting antenna TT inside the radio wave reverberation chamber, place the forwarding terminal and forwarding receiving antenna TR outside the radio wave reverberation chamber, place the receiving terminal and receiving antenna RR in the internal working space of the radio wave reverberation chamber, and connect the receiving terminal to the host computer; S12: No electromagnetic interference signal is applied in the radio wave reverberation chamber, the GNSS navigation repeater and GNSS navigation receiver are debugged, and the three-dimensional coordinates are set as reference indicators; S13: Point the transmitting antenna T toward the corner of the radio wave reverberation chamber, and set the receiving antenna R in the internal working space of the radio wave reverberation chamber.

[0013] Preferably, step S2 specifically includes the following steps: S21: From the starting frequency First, adjust the RF signal source and inject input power into the transmitting antenna T. , forming a test level in the radio wave reverberation room E p ; S22: Monitor the receiving power in the radio wave reverberation chamber through the receiving antenna R and the spectrum analyzer .

[0014] Preferably, in step S21, the input power The specific settings are: ;

[0015] in, AVF It represents the ratio of the average received power to the input power in the no-load state of the radio reverberation chamber. CVF It represents the ratio of the average received power to the input power in the radio reverberation chamber under the loaded state. E test Indicates the field strength, It represents the normalized mean field strength of the radio reverberation chamber in the no-load state.

[0016] Therefore, the present invention adopts the above-mentioned GNSS navigation signal coexistence test system and sensitivity threshold evaluation method, which has the following beneficial effects: (1) This solution simulates the electromagnetic fading characteristics of wireless signals in a real environment by using a radio wave reverberation chamber. By changing the field distribution in the chamber using a mechanical stirrer or an electronic stirrer, the same fading conditions can be accurately reproduced, facilitating repeated testing and comparison of results. (2) This solution utilizes the high quality factor of the radio reverberation chamber to create a high-level test environment with a relatively small input power within a wide frequency band, while ensuring the accuracy, repeatability, and statistical reliability of the test. It can accurately find the critical field strength at which the device fails and improve the accuracy of the threshold assessment. (3) This solution does not require the construction of a complex environment on site, which can significantly reduce testing costs and time. By quickly generating a large number of fading samples, it can complete long-term statistical characteristics evaluation in a short time.

[0017] The method scheme of the present invention is further described in detail below through the drawings and examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a structural diagram of a GNSS navigation signal coexistence test system according to the present invention; Figure 2 This is a flow chart of a sensitivity threshold evaluation method for a GNSS navigation signal coexistence test system according to the present invention; Figure 3 This is a signal control principle diagram of a GNSS navigation signal coexistence test system of the present invention.

[0019] Among them: 1. Host computer; 2. Mechanical stirrer; 3. RF signal source; 4. RF power amplifier; 5. Spectrum analyzer; 6. Transmitting antenna T; 7. Receiving antenna R; 8. Forwarding terminal; 9. Forwarding receiving antenna TR; 10. Forwarding transmitting antenna TT; 11. Receiving terminal; 12. Receiving antenna RR. DETAILED DESCRIPTION

[0020] The method scheme of the present invention is further described below through the drawings and examples.

[0021] Unless otherwise defined, technical terms or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0022] The words “include” or “comprising” and similar words used in the present invention mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of also including other elements. The orientation or position relationship indicated by the terms “inside”, “outside”, “upper”, “lower”, etc. is based on the orientation or position relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention. When the absolute position of the described object changes, the relative position relationship may also change accordingly. In the present invention, unless otherwise clearly stipulated and limited, the terms such as “attachment” should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral whole; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0023] Example

[0024] like Figure 1 As shown, this embodiment provides a GNSS navigation signal coexistence test system, including a radio wave reverberation chamber, a GNSS navigation signal repeater, a GNSS navigation signal receiver and a host computer 1. The radio wave reverberation chamber includes a mechanical stirrer 2, a radio frequency signal source 3, a radio frequency power amplifier 4, a spectrum analyzer 5, a transmitting antenna T6 and a receiving antenna R7, which form the required peak field strength in a wide frequency range of 100MHz-18GHz. And simulate the multipath scattering of electromagnetic waves in the real environment through reflection on the wall.

[0025] The GNSS navigation signal repeater includes a repeater terminal 8 , a repeater receiving antenna TR9 and a repeater transmitting antenna TT10 , and the GNSS navigation signal receiver includes a receiving terminal 11 and a receiving antenna RR12 .

[0026] For the radio wave reverberation chamber, the upper computer 1 controls the mechanical stirrer 2 to step, thereby changing the boundary conditions inside the cavity. Ultimately, a statistically uniform and randomly polarized test environment is formed in a working space that is no less than one-quarter wavelength away from the cavity wall and has the lowest usable frequency.

[0027] Due to the high quality factor of the radio reverberation chamber, a smaller input power is injected through the transmitting antenna T6. , which can form a very strong field E test , for this characteristic, at a given frequency , the host computer 1 controls the output and frequency of the RF signal source 3 The corresponding signal level is amplified by the RF power amplifier 4 and injected into the radio wave reverberation chamber by the transmitting antenna T6, forming the test level required for the GNSS navigation signal coexistence test in the radio wave reverberation chamber. E p .

[0028] At the same time, in order to ensure that a certain power is injected into the radio wave reverberation room, it is also necessary to use the receiving antenna R7 placed in the working space to measure the received power The power level is displayed by the spectrum analyzer 5, and the received power is recorded and saved by the host computer 1. .

[0029] For GNSS navigation, the forwarding receiving antenna TR9 receives the GNSS navigation signal and inputs it into the receiving terminal 11, which is then sent to the radio wave reverberation chamber through the forwarding transmitting antenna TT10. In the radio wave reverberation chamber, the navigation signal is transmitted multiple times by the metal wall, which can be used to simulate the multipath reflection effect in a real environment. Based on this characteristic, the receiving antenna RR12 receives the GNSS navigation signal and forwards it to the host computer 1 through the receiving terminal 11. The three-dimensional coordinates of the navigation signal are used to determine the coexistence capability of the GNSS navigation signal.

[0030] The RF signal source 3 is connected to the RF power amplifier 4 through an RF coaxial cable, the RF power amplifier 4 is connected to the transmitting antenna T6 through a cable, the spectrum analyzer 5 is connected to the receiving antenna R7 through a cable, the forwarding terminal 8 is connected to the forwarding receiving antenna TR9 through a cable, the forwarding terminal 8 is connected to the forwarding transmitting antenna TT10 through a cable, the host computer 1 is connected to the receiving terminal 11 through a cable, and the receiving terminal 11 is connected to the receiving antenna RR12 through a cable.

[0031] The forwarding terminal 8, the forwarding receiving antenna TR9 and the host computer 1 are all set outside the radio wave reverberation chamber. The host computer 1 is set as a computer PC. A monitoring unit is set inside the computer PC for controlling the radio wave reverberation chamber system and monitoring the GNSS navigation signal under the action of electromagnetic interference.

[0032] The forwarding transmitting antenna TT10, the receiving terminal 11 and the receiving antenna RR12 are all arranged inside the radio wave reverberation chamber. The distance between the receiving terminal 11 and the metal wall and the distance between the receiving antenna RR12 and the metal wall are not less than one quarter wavelength of the test frequency.

[0033] like Figure 2 As shown, a sensitivity threshold evaluation method for a GNSS navigation signal coexistence test system includes the following steps: S1: Configure the internal experimental environment of the radio reverberation chamber to determine the test frequency range of the GNSS navigation signal receiver to be tested Frequency intervals and test levels E p , change the position of the mechanical stirrer j Set to j =0; In step S1, the test level E p Set to the maximum field strength expected for GNSS navigation signal coexistence in the actual environment.

[0034] In step S1, the internal experimental environment of the radio wave reverberation chamber is configured, which specifically includes the following steps: S11: Place the forwarding transmitting antenna TT inside the radio wave reverberation chamber, place the forwarding terminal and forwarding receiving antenna TR outside the radio wave reverberation chamber, place the receiving terminal and receiving antenna RR in the internal working space of the radio wave reverberation chamber, and connect the receiving terminal to the host computer; S12: No electromagnetic interference signal is applied to the radio wave reverberation chamber. The GNSS navigation transponder and GNSS navigation receiver are debugged. The three-dimensional coordinates are set as reference indicators to ensure that the GNSS navigation receiver operates normally. S13: Point the transmitting antenna T toward the corner of the radio wave reverberation chamber to avoid direct irradiation of the antenna and GNSS navigation receiver terminal in the working space, and set the receiving antenna R in the internal working space of the radio wave reverberation chamber.

[0035] S2: Mechanical stirrer steps to position j = j +1 for a given frequency , injected input power , forming the test level E p ; Step S2 specifically includes the following steps: S21: From the starting frequency First, adjust the RF signal source and inject input power into the transmitting antenna T. , forming a test level in the radio reverberation room E p ; In step S21, the input power The specific settings are:

[0036] in, AVF It represents the ratio of the average received power to the input power in the no-load state of the radio reverberation chamber. CVF It represents the ratio of the average received power to the input power in the radio reverberation chamber under the loaded state. E test Indicates the field strength, It represents the normalized mean field strength of the radio reverberation chamber in the no-load state.

[0037] S22: Monitor the receiving power in the radio wave reverberation chamber through the receiving antenna R and the spectrum analyzer .

[0038] S3: For a given frequency , according to the three-dimensional coordinates, determine the desired test level E p Under the same conditions, the coexistence capability of GNSS navigation signals is tested. If GNSS navigation signals coexist, it means that the GNSS navigation receiver under test can work normally. Then record the coexistence capability of GNSS navigation signals under the same conditions. If the coexistence capability of GNSS navigation signals is tested, it means that the GNSS navigation receiver under test can work normally. The corresponding peak field strength and peak received power ; S4: If there is a coexistence problem with the GNSS navigation signal, it indicates that the GNSS navigation receiver under test is interfered with and is working abnormally. Adjust the input power. , input power Reduce the test level in the radio reverberation room E p It is also reduced accordingly, allowing the GNSS navigation signal to coexist and record the input power The corresponding peak field strength and peak received power ; S5: Control the mechanical stirrer step by step through the host computer N Position, determine the position of the mechanical stirrer j and set position number N If the relationship between the position of the mechanical stirrer j Not more than the set position number N , repeat steps S1 to S4; S6: If the position of the mechanical stirrer j Greater than the set position number N， For any frequency , record separately N Test level corresponding to the coexistence of two GNSS navigation signalsE p , extract the test level E p The minimum value of the frequency Sensitive threshold for coexistence of GNSS navigation signals.

[0039] For a given frequency and N Positions, at test level E p If the GNSS navigation signals can coexist under the action of the test signal, it means that the GNSS navigation receiver under test is working normally. E p is the GNSS navigation signal coexistence sensitivity threshold; if the test level E p The GNSS navigation receiver under test works abnormally under the action of Post-test level E p Reduced to peak field strength , and in N If the GNSS navigation receivers under test can all work normally at the same location, it means that the peak field strength is the GNSS navigation signal coexistence sensitivity threshold.

[0040] like Figure 3 As shown, the host computer 1 sets the given frequency of the RF signal source 3 online. and level , Set the initial position of mechanical stirrer 2 j , select typical indicators of GNSS navigation signals. In this embodiment, the typical indicators selected are three-dimensional coordinates; Before starting the test, do not apply electromagnetic interference to ensure that stable GNSS navigation communication is established in the radio reverberation chamber. After starting the test, control the virtual switch to open and , the level of RF signal source 3 With a gain of 4 RF power amplifier G Add together as the injected input power of the radio reverberation chamber , and form the desired test level E p ; According to virtual diagnosis, at the test level E p Under the action, determine whether the selected typical indicators are normal. If normal, according to the test frequency range Select the test frequency points sequentially and inject input power again through virtual switch control , and use virtual diagnosis to determine whether typical indicators are normal; If the selected typical indicators are abnormal according to virtual diagnosis, the test level in the radio reverberation room needs to be lowered. E p , that is, adjust the signal level of RF signal source 3 set up; For mechanical stirrer 2, set the number of stirring positions N , according to the virtual judgment, determine ceil( k / n )and N The relative size of , where ceil is the upward rounding function, k = count, indicating that the virtual switch is in the off state and the signal level of RF signal source 3 is The count of, count is the counting function, n Test frequency range The corresponding frequency number in ; Especially, when k =1, n =20,ceil( k / n )=1; k =15, n =20,ceil( k / n )=1; k =21, n =20,ceil( k / n )=2; If ceil( k / n )≤ N , then according to the virtual logic operation, use j = j +ceil( k / n ) calculates the current position; otherwise, ends the test.

[0041] Therefore, the present invention adopts the above-mentioned GNSS navigation signal coexistence test system and sensitivity threshold evaluation method, utilizes the multipath scattering characteristics of the radio wave reverberation chamber to simulate the fading characteristics of wireless signals in a real environment, and utilizes the high quality factor of the radio wave reverberation chamber to form a high-level test environment with a small input power within a wide bandwidth, thereby realizing GNSS navigation signal coexistence testing and quantitative evaluation and analysis of sensitivity thresholds.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the method scheme of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary method personnel in this field should understand that they can still modify or replace the method scheme of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified method scheme to deviate from the spirit and scope of the method scheme of the present invention.

Claims

1. A GNSS navigation signal coexistence test system, characterized in that: It includes a radio wave reverberation chamber, a GNSS navigation signal repeater, a GNSS navigation signal receiver and a host computer. The radio wave reverberation chamber includes a mechanical stirrer, a radio frequency signal source, a radio frequency power amplifier, a spectrum analyzer, a transmitting antenna T and a receiving antenna R. The GNSS navigation signal repeater includes a forwarding terminal, a forwarding receiving antenna TR and a forwarding transmitting antenna TT. The GNSS navigation signal receiver includes a receiving terminal and a receiving antenna RR.

2. A GNSS navigation signal coexistence test system according to claim 1, characterized in that: The RF signal source and RF power amplifier are connected through an RF coaxial cable, the RF power amplifier and transmitting antenna T are connected through a cable, the spectrum analyzer and receiving antenna R are connected through a cable, the forwarding terminal and forwarding receiving antenna TR are connected through a cable, the forwarding terminal and forwarding transmitting antenna TT are connected through a cable, the host computer and receiving terminal are connected through a cable, and the receiving terminal and receiving antenna RR are connected through a cable.

3. A GNSS navigation signal coexistence test system according to claim 1, characterized in that: The forwarding terminal, forwarding receiving antenna TR and host computer are all arranged outside the radio wave reverberation chamber. The host computer is set as a computer PC. A monitoring unit is set inside the computer PC. The forwarding transmitting antenna TT, receiving terminal and receiving antenna RR are all arranged inside the radio wave reverberation chamber. The distance between the receiving terminal and the metal wall surface, and the distance between the receiving antenna RR and the metal wall surface are not less than one-quarter wavelength of the test frequency.

4. A sensitivity threshold evaluation method for a GNSS navigation signal coexistence test system according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: Configure the internal experimental environment of the radio reverberation chamber to determine the test frequency range of the GNSS navigation signal receiver to be tested Frequency intervals and test levels E p , change the position of the mechanical stirrer j Set to j =0; S2: Mechanical stirrer steps to position j = j +1 for a given frequency , injected input power , forming the test level E p ; S3: For a given frequency , according to the three-dimensional coordinates, determine the desired test level E p Under the coexistence capability of GNSS navigation signals, if GNSS navigation signals coexist, record the coexistence with input power. The corresponding peak field strength and peak received power ; S4: If there are coexistence issues with GNSS navigation signals, adjust the input power , so that GNSS navigation signals coexist, record and input power The corresponding peak field strength and peak received power ; S5: Determine the position of the mechanical stirrer j and set position number N If the relationship between the position of the mechanical stirrer j Not more than the set number of positions N , repeat steps S1 to S4; S6: If the position of the mechanical stirrer j Greater than the set number of positions N， For any frequency , record separately N Test level corresponding to the coexistence of two GNSS navigation signals E p , extract the test level E p The minimum value of the frequency Sensitive threshold for coexistence of GNSS navigation signals.

5. The sensitivity threshold evaluation method of a GNSS navigation signal coexistence test system according to claim 4, characterized in that: In step S1, the test level E p Set to the maximum field strength expected for coexistence of GNSS navigation signals in a real environment.

6. The sensitivity threshold evaluation method of a GNSS navigation signal coexistence test system according to claim 4, characterized in that: In step S1, the internal experimental environment of the radio wave reverberation chamber is configured, which specifically includes the following steps: S11: Place the forwarding transmitting antenna TT inside the radio wave reverberation chamber, place the forwarding terminal and forwarding receiving antenna TR outside the radio wave reverberation chamber, place the receiving terminal and receiving antenna RR in the internal working space of the radio wave reverberation chamber, and connect the receiving terminal to the host computer; S12: No electromagnetic interference signal is applied in the radio wave reverberation chamber, the GNSS navigation repeater and GNSS navigation receiver are debugged, and the three-dimensional coordinates are set as reference indicators; S13: Point the transmitting antenna T toward the corner of the radio wave reverberation chamber, and set the receiving antenna R in the internal working space of the radio wave reverberation chamber.

7. The sensitivity threshold evaluation method of a GNSS navigation signal coexistence test system according to claim 4, characterized in that: Step S2 specifically includes the following steps: S21: From the starting frequency First, adjust the RF signal source and inject input power into the transmitting antenna T. , forming a test level in the radio wave reverberation room E p ; S22: Monitor the receiving power in the radio wave reverberation chamber through the receiving antenna R and the spectrum analyzer .

8. The sensitivity threshold evaluation method of a GNSS navigation signal coexistence test system according to claim 7, characterized in that: In step S21, the input power The specific settings are: ； in, AVF It represents the ratio of the average received power to the input power in the no-load state of the radio reverberation chamber. CVF It represents the ratio of the average received power to the input power in the radio reverberation chamber under the loaded state. E test Indicates the field strength, It represents the normalized mean field strength of the radio reverberation chamber in the no-load state.

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