A multi-antenna navigation anechoic chamber test signal level fast calibration method

Abstract

The application discloses a kind of multi-antenna navigation darkroom test signal level fast calibration method, belong to satellite navigation user equipment test technical field.First, the test system of single star multi-output navigation signal simulator, time-frequency reference, monitoring receiver and its zero-phase center antenna is constructed;Through metrology, the power processing zero value of monitoring receiver at each frequency point is obtained, and the frequency point-azimuth-elevation three-dimensional database of zero-phase center antenna gain is calibrated in advance.During calibration, monitoring receiver antenna is fixed on the turntable, access time-frequency reference, and the simulator simultaneously broadcasts multi-channel, multi-frequency point navigation signal at maximum nominal value, monitoring receiver parallelly measures each link received power, and the actual test signal level of darkroom each antenna face and link attenuation are deduced by combining antenna gain and power zero value.The application is suitable for the batch calibration of multi-antenna navigation darkroom (full sky star darkroom) test signal level.

Description

Technical Field

[0001] This invention relates to the field of satellite navigation user equipment testing technology, specifically to a method for rapidly calibrating the test signal level in a multi-antenna navigation anechoic chamber by utilizing the characteristics of multi-system, multi-frequency, and multi-channel parallel reception of a monitoring receiver. This method is suitable for automated, high-precision, and rapid calibration of test signal levels in a multi-antenna navigation anechoic chamber. Background Technology

[0002] With the development of satellite navigation technology, multi-antenna navigation anechoic chambers are widely used for performance testing of navigation receivers. Multiple navigation antennas are deployed within the anechoic chamber to simulate a multi-satellite, multi-frequency testing environment. To ensure the accuracy of test results, the test signal levels from each radiating antenna within the anechoic chamber to the test area must be precisely calibrated. Traditional methods for calibrating test signal levels in multi-antenna navigation anechoic chambers typically involve calibrating each signal link level individually using a vector network analyzer or a single-channel receiver, resulting in low calibration efficiency and poor repeatability. This invention proposes a rapid calibration method for test signal levels in multi-antenna navigation test anechoic chambers based on a monitoring receiver. This method enables rapid calibration of multiple navigation test signal levels reaching the antenna aperture of the navigation terminal, effectively shortening calibration time and reducing the complexity of link calibration. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of traditional multi-antenna navigation anechoic chamber test signal level calibration processes, such as low efficiency and unstable phase center. A rapid calibration method for multi-antenna navigation anechoic chamber test signal levels is designed, utilizing the parallel reception characteristics of a monitoring receiver with multiple systems, multiple frequencies, and multiple channels to achieve rapid calibration of multi-antenna, multi-frequency test signal levels in multi-antenna navigation anechoic chambers. This effectively solves the problems of low measurement efficiency and poor repeatability when using traditional calibration methods in multi-antenna navigation anechoic chambers.

[0004] To achieve the above objectives, a method for rapid calibration of test signal levels in a multi-antenna navigation anechoic chamber includes the following steps:

[0005] Step 1: Construct a multi-antenna navigation anechoic chamber and supporting testing equipment: a multi-antenna navigation anechoic chamber, a single-satellite multi-output navigation signal simulator, a time and frequency reference, and a monitoring receiver (the monitoring receiver is equipped with a zero-phase center antenna).

[0006] Step 2: Obtain the signal level reception and processing zero value of the monitoring receiver at each frequency point through measurement or testing, that is, the difference between the measured value of the signal power reported by the monitoring receiver and the nominal value.

[0007] Step 3: Obtain the zero-phase center antenna pattern of the monitoring receiver through measurement or testing, and establish a three-dimensional database of antenna gain in frequency, azimuth, and elevation.

[0008] Step 4: Fix the zero-phase center antenna of the monitoring receiver on the test turntable. The azimuth of the zero-phase center antenna is consistent with the azimuth of the test turntable. The 10MHz time-frequency reference and the 1pps system reference signal are connected to the monitoring receiver as reference clocks.

[0009] Step 5: Start the single-satellite multi-output navigation signal simulator to broadcast multiple outputs and multiple frequency points of fixed scene navigation signals. Set the signal level to the maximum nominal value of the simulator output. Obtain the power measurement values ​​of all channel links by monitoring the observations output by the receiver. Based on this, complete the test signal level calibration of multiple antennas and multiple frequency points, and further calculate the link attenuation value of multiple antennas at each navigation frequency point.

[0010] Step 6: Change the output of the single-satellite multi-output navigation signal simulator to multiple other navigation antennas, and repeat Step 5 until the calibration of all test signal levels in the multi-antenna navigation anechoic chamber is completed.

[0011] Furthermore, the specific process of step 5 is as follows:

[0012] Step 501: The single-satellite multi-output navigation signal simulator outputs multiple channels, each with multiple frequency points for navigation signals, wherein the output signal power is the navigation signal with the maximum nominal value. ;

[0013] Step 502: Record the relationship between the output channel of the single-satellite multi-output navigation signal simulator and the corresponding simulated satellite number, where the output channel corresponds to the anechoic chamber antenna number;

[0014] Step 503: Set the monitoring receiver to work in link verification mode, and output the received signal levels of all receiving channels throughout the entire link verification process. ,in, Indicates satellite number, Indicates frequency point;

[0015] Step 504: Based on the satellite number received by the monitoring receiver, obtain the azimuth and elevation angles of the receiving antenna number corresponding to the current channel in the multi-antenna navigation anechoic chamber layout, and extract the corresponding antenna gain from the frequency-azimuth-elevation three-dimensional database. ,in, Indicates frequency point, Refers to the antenna azimuth angle. Refers to the antenna elevation angle;

[0016] Step 505, based on the received signal level Antenna gain Zero power value Calculations are performed to calibrate the levels of multi-channel navigation test signals from multiple antennas and multiple frequency points;

[0017] Step 506: Calculate the link attenuation of multiple antennas at each navigation frequency point based on the maximum nominal value signal output by the navigation signal simulator and the received signal level.

[0018] The present invention has the following advantages:

[0019] This invention utilizes the characteristics of multi-system, multi-frequency, and multi-channel parallel reception of a monitoring receiver, and pre-obtains the gain of the zero-phase center antenna at different frequencies, azimuth angles, and elevation angles to achieve rapid and automated calibration of the test signal level in a multi-antenna navigation anechoic chamber. The test signal level measurement process is simpler and more efficient than traditional calibration methods. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating the principle of signal level calibration for multi-antenna navigation anechoic chamber testing using a monitoring receiver. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0022] ① Construct a multi-antenna navigation anechoic chamber and supporting testing equipment: multi-antenna navigation anechoic chamber, single-satellite multi-output navigation signal simulator, test turntable, time and frequency reference, monitoring receiver (including zero-phase center antenna);

[0023] Multi-antenna navigation anechoic chamber: also known as a starry sky anechoic chamber, is used to simulate the navigation signal receiving environment of a navigation terminal under laboratory conditions. Multiple navigation antennas are deployed inside the microwave anechoic chamber to simulate the actual navigation satellite constellation. The phase centers of the multiple antennas inside the navigation anechoic chamber relative to the test turntable are known.

[0024] Single-satellite multi-output navigation signal simulator: Used in conjunction with a multi-antenna navigation anechoic chamber, it typically has no fewer than 12 individually output channels, each simulating the navigation signal output by a single navigation satellite. A multi-antenna navigation anechoic chamber and its associated testing equipment can be configured with multiple single-satellite multi-output navigation signal simulators, improving the accuracy of navigation constellation simulation.

[0025] Time and frequency reference: Provides a unified time and frequency reference for the system, where the zero pseudorange scenario output by the navigation signal simulator corresponds to the system reference of 1pps.

[0026] Monitoring Receiver (including zero-phase-center antenna): A dedicated navigation signal receiver that can be configured to operate in different modes to meet calibration requirements. A zero-phase-center antenna means that its phase center remains constant when receiving navigation signals from different directions; that is, the pseudorange after reaching the zero-phase-center antenna from different directions remains unchanged.

[0027] ② Obtain the zero value of the receiving processing at each frequency point of the monitoring receiver through measurement or testing, that is, the difference between the measured value of the signal power reported by the monitoring receiver and the nominal value. ( (representing frequency point)

[0028] ③ Obtain the zero-phase center antenna pattern of the monitoring receiver through measurement or testing, and establish a three-dimensional database of antenna gain in terms of frequency, azimuth, and elevation. ( Indicates frequency point, Refers to the antenna azimuth angle. (Refers to the antenna elevation angle)

[0029] ④ Fix the zero-phase center antenna of the monitoring receiver on the test turntable. The azimuth of the zero-phase center antenna at 0 degrees is consistent with the azimuth of the test turntable at 0 degrees. The 10MHz time-frequency reference and the 1pps system reference signal are connected to the monitoring receiver as reference clocks.

[0030] ⑤ The single-satellite multi-output navigation signal simulator broadcasts multiple outputs and multiple frequency points of fixed pseudorange navigation signals. The signal level is the maximum nominal value of the simulator output. By monitoring the observations output by the receiver, the power measurement values ​​of all channel links are obtained, the test signal level calibration of multiple antennas and multiple frequency points is completed, and the link attenuation values ​​of multiple antennas at each navigation frequency point are further obtained.

[0031] (501) The single-satellite multi-output navigation signal simulator outputs multiple channels, each channel with multiple frequency points of navigation signal, wherein the output signal power is the navigation signal with the maximum nominal value. ;

[0032] The number of channels output by the single-satellite multi-output navigation signal simulator should not exceed the maximum receiving channel capacity of the monitoring receiver. For example, if the monitoring receiver receives 12 channels per frequency point, then the maximum number of channels output by the single-satellite multi-output navigation signal simulator is 12.

[0033] (502) Record the relationship between the output channels (corresponding to the anechoic chamber antenna number) of the single-satellite multi-output navigation signal simulator and the corresponding simulated satellite number;

[0034] (503) Set the monitoring receiver to work in link calibration mode, that is, output the link receiving signal level of all receiving channels during the entire link verification process. ( This indicates the antenna signal of the starry sky darkroom. Indicates satellite number, (representing frequency point)

[0035] (504) Based on the satellite number received by the monitoring receiver, obtain the azimuth and elevation angle of the receiving antenna number corresponding to the current channel in the multi-antenna navigation anechoic chamber layout, and extract the corresponding antenna gain from the frequency-azimuth-elevation three-dimensional database. ( Indicates frequency point, Refers to the antenna azimuth angle. (Refers to the antenna elevation angle)

[0036] (505) Based on the received signal level Antenna gain Zero power value And perform calculations to achieve multi-channel navigation test signal levels. The calibration and calculation process is as follows:

[0037]

[0038] in:

[0039] The antenna number indicating the darkroom with a starry sky;

[0040] Indicates frequency point;

[0041] Refers to the azimuth angle of the antenna;

[0042] Refers to the antenna elevation angle.

[0043] (506) Calculate the link attenuation of multiple antennas at each navigation frequency point based on the maximum nominal signal output by the navigation signal simulator and the received signal level.

[0044]

[0045] ⑥ Change the output signal of the single-satellite multi-output navigation signal simulator to multiple other navigation antennas, and repeat step ⑤ to complete the calibration of all test signal levels in the multi-antenna navigation anechoic chamber. Assuming the multi-antenna navigation anechoic chamber has 72 navigation antennas, at least 6 measurements are required to complete the calibration of all link test signal levels.

Claims

1. A method for rapid calibration of signal levels in a multi-antenna navigation anechoic chamber test, characterized in that, Includes the following steps: Step 1: Construct a multi-antenna navigation anechoic chamber and supporting testing equipment: a multi-antenna navigation anechoic chamber, a single-satellite multi-output navigation signal simulator, a time and frequency reference, and a monitoring receiver (the monitoring receiver is equipped with a zero-phase center antenna). Step 2: Obtain the signal level reception and processing zero value of the monitoring receiver at each frequency point through measurement or testing, that is, the difference between the measured value of the signal power reported by the monitoring receiver and the nominal value. Step 3: Obtain the zero-phase center antenna pattern of the monitoring receiver through measurement or testing, and establish a three-dimensional database of antenna gain in frequency, azimuth, and elevation. Step 4: Fix the zero-phase center antenna of the monitoring receiver on the test turntable. The azimuth of the zero-phase center antenna is consistent with the azimuth of the test turntable. The 10MHz time-frequency reference and the 1pps system reference signal are connected to the monitoring receiver as reference clocks. Step 5: Start the single-satellite multi-output navigation signal simulator to broadcast multiple outputs of fixed scene navigation signals at multiple frequencies. Set the signal level to the maximum nominal value of the simulator output. By monitoring the observations output by the receiver, the power measurement values ​​of all channel links are obtained. Based on this, the test signal level calibration of multiple antennas at multiple frequencies is completed, and the link attenuation value of multiple antennas at each navigation frequency is further calculated. Step 6: Change the output of the single-satellite multi-output navigation signal simulator to multiple other navigation antennas, and repeat Step 5 until the calibration of all test signal levels in the multi-antenna navigation anechoic chamber is completed.

2. The rapid calibration method for test signal levels in a multi-antenna navigation anechoic chamber according to claim 1, characterized in that: The specific process of step 5 is as follows: Step 501: The single-satellite multi-output navigation signal simulator outputs multiple channels, each with multiple frequency points for navigation signals, wherein the output signal power is the navigation signal with the maximum nominal value. ; Step 502: Record the relationship between the output channel of the single-satellite multi-output navigation signal simulator and the corresponding simulated satellite number, where the output channel corresponds to the anechoic chamber antenna number; Step 503: Set the monitoring receiver to work in link verification mode, and output the received signal levels of all receiving channels throughout the entire link verification process. ,in, Indicates satellite number, Indicates frequency point; Step 504: Based on the satellite number received by the monitoring receiver, obtain the azimuth and elevation angle of the receiving antenna number corresponding to the current channel in the multi-antenna navigation anechoic chamber layout, and extract the corresponding antenna gain from the frequency-azimuth-elevation-gain four-dimensional database. ,in, Indicates frequency point, Refers to the antenna azimuth angle. Refers to the antenna elevation angle; Step 505, based on the received signal level Antenna gain Zero power value Calculations are performed to calibrate the levels of multi-channel navigation test signals from multiple antennas and multiple frequency points; Step 506: Calculate the link attenuation of multiple antennas at each navigation frequency point based on the maximum nominal value signal output by the navigation signal simulator and the received signal level.

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