Satellite navigation antenna delay measurement method and system

Abstract

This invention discloses a method and system for measuring the delay of a satellite navigation antenna. In one specific embodiment, the method includes: connecting the antenna under test to a satellite navigation receiver, receiving satellite signals using the antenna under test, performing local clock calibration using the satellite navigation receiver, and acquiring a first pseudorange corresponding to the target satellite; disconnecting the antenna under test from the satellite navigation receiver, connecting the satellite navigation receiver's own antenna to the satellite navigation receiver, receiving satellite signals using the own antenna, and acquiring a second pseudorange corresponding to the target satellite before the satellite navigation receiver completes local clock calibration; and calculating the delay of the antenna under test using the first and second pseudoranges. This embodiment relaxes the requirements for the measurement site and auxiliary testing equipment, and is not limited by the testing site and equipment; this invention is also applicable to scenarios where the satellite antenna is replaced during use.

Description

Technical Field

[0001] This invention relates to the field of satellite navigation. More specifically, it relates to a method and system for measuring the delay of a satellite navigation antenna. Background Technology

[0002] The core of satellite navigation antenna delay measurement is measuring the group delay of the radio frequency path from the antenna's electrical port to the phase center, and then breaking it down into two interchangeable metrics: transmit delay and receive delay. Currently, engineering and metrology institutions can categorize satellite navigation antenna delay measurement methods into the following four types.

[0003] The first type is the closed-loop standard antenna and vector network analyzer method. The principle of this method is to align the antenna under test in the far field of a microwave anechoic chamber to form a transmit-receive closed loop, use a VNA to measure the S21 phase slope, and subtract the delay of the cable, spatial propagation, and the reference antenna itself to obtain the time delay of the antenna under test.

[0004] The second type is the two-way time delay transfer instrument field method. This method is suitable for large-size ground stations or satellite-borne antennas that cannot be placed in an anechoic chamber. The measurement method involves connecting a portable time delay transfer instrument to the transmitting channel under test via a short cable and recording the combined pseudorange; then connecting the same instrument to the receiving channel under test and recording the pseudorange a second time; subtracting the original delay yields the transmission and reception delays.

[0005] The third type is the simulator-based zero-time end-to-end method. This method requires a GNSS RF signal simulator and a high-speed digital oscilloscope. The measurement method involves the simulator broadcasting L1 and L2 signals with fixed timestamps at time t0. The antenna under test is connected to the receiver, and the receiver outputs PPS simultaneously. The oscilloscope simultaneously acquires the simulator's 10MHz reference and the receiver's PPS, measuring the delay as tPPS - t0. Subtracting the receiver's internal delay from this delay yields the antenna delay.

[0006] The fourth type is the ultra-short baseline dual-antenna differential method. This method is suitable for situations where only a standard laboratory is available, without an anechoic chamber or simulator. The measurement method involves placing a calibrated reference antenna A and the antenna under test B 1m apart, facing the sky. Two identical receivers share a clock and synchronously acquire 30 minutes of dual-frequency pseudorange and carrier phase data. The instrument delay difference is estimated using a carrier phase double-difference model. Because the baseline is 1m, ionospheric, tropospheric, and ephemeris errors are almost entirely eliminated, leaving only the antenna differential delay.

[0007] The above methods are accurate, but are limited by the testing site and equipment. These methods cannot be implemented when only the antenna under test and a satellite navigation receiver are available on site. Summary of the Invention

[0008] The purpose of this invention is to provide a satellite navigation antenna delay measurement method and system to solve at least one of the problems existing in the prior art.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of this invention provides a method for measuring the delay of a satellite navigation antenna, the method comprising: Connect the antenna under test to the satellite navigation receiver, use the antenna under test to receive satellite signals, use the satellite navigation receiver to perform local clock calibration, and collect the first pseudorange corresponding to the target satellite; Disconnect the antenna under test from the satellite navigation receiver, connect the satellite navigation receiver's own antenna to the satellite navigation receiver, use its own antenna to receive satellite signals, and before the satellite navigation receiver completes local clock calibration, collect the second pseudorange corresponding to the target satellite; The time delay of the antenna under test is calculated using the first pseudorange and the second pseudorange.

[0010] Optionally, the first pseudorange corresponding to the target satellite and the satellite navigation receiver includes:

[0011] In the formula, This is the first pseudorange; The local time of the satellite navigation receiver; The time at which satellite signals are transmitted to the target satellite; The time delay is the time delay of the antenna under test; It is the speed of light.

[0012] Optionally, the second pseudorange corresponding to the target satellite acquired by the satellite navigation receiver includes:

[0013] In the formula, This is the second pseudorange; The local time of the satellite navigation receiver; The time at which satellite signals are transmitted to the target satellite; It is the speed of light.

[0014] Optionally, calculating the time delay of the antenna under test using the first pseudorange and the second pseudorange includes:

[0015] In the formula, This is the first pseudorange; This is the second pseudorange; The time delay is the time delay of the antenna under test; It is the speed of light.

[0016] Optionally, the signal transmission delay of the antenna itself is less than the signal transmission delay of the antenna under test.

[0017] Optionally, the signal transmission delay of the antenna under test is on the order of milliseconds.

[0018] Optionally, the signal transmission delay of the antenna itself is on the order of nanoseconds.

[0019] Optionally, the antenna under test is a generalized satellite signal receiving link, including any one of a passive satellite navigation antenna, a satellite signal forwarding link, and an anti-interference antenna signal receiving link.

[0020] Optionally, the total duration of the second pseudorange corresponding to the target satellite acquired by the satellite navigation receiver is less than 5 seconds.

[0021] A second aspect of the present invention provides a satellite navigation antenna delay measurement system, the system comprising: A satellite navigation receiver is used to connect to the antenna under test, receive satellite signals using the antenna under test, complete local clock calibration, and acquire the first pseudorange corresponding to the target satellite. It is also used to disconnect the antenna under test, connect its own antenna, and use its own antenna to receive satellite signals. Before completing local clock calibration, it can collect the second pseudorange corresponding to the target satellite. It is also used to calculate the time delay of the antenna under test using the first pseudorange and the second pseudorange.

[0022] The beneficial effects of this invention are as follows: The technical solution described in this invention provides a method for measuring the delay of a satellite navigation antenna using pseudorange, which relaxes the requirements for the measurement site and auxiliary testing instruments and equipment, and is not limited by the testing site and equipment. This invention is also applicable to scenarios where satellite antennas are replaced during use. The initial delay of the antenna under test is calculated by the pseudorange difference before and after the antenna replacement. This invention can promptly identify and take measures to shorten the signal reacquisition process, and has real-time performance. This invention can measure a generalized antenna under test using a common single-frequency, single-point positioning receiver, and can obtain millisecond-level delay measurement accuracy. Attached Figure Description

[0023] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0024] Figure 1 This diagram illustrates the process of satellite navigation antenna delay measurement provided in an embodiment of the present invention. Detailed Implementation

[0025] To more clearly illustrate the present invention, the following description, in conjunction with embodiments and accompanying drawings, further explains the invention. Similar components in the drawings are indicated by the same reference numerals. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0026] The core of satellite navigation antenna delay measurement is measuring the group delay of the radio frequency path from the antenna's electrical port to the phase center, and then breaking it down into two interchangeable metrics: transmit delay and receive delay. Currently, engineering and metrology institutions can categorize satellite navigation antenna delay measurement methods into four types. However, while these methods are accurate, they are limited by the test site and equipment. When only the antenna under test and a satellite navigation receiver are available on-site, these methods cannot be implemented.

[0027] In view of this, such as Figure 1 As shown, one embodiment of the present invention provides a method for measuring the delay of a satellite navigation antenna. The method includes: connecting the antenna under test to a satellite navigation receiver, receiving satellite signals using the antenna under test, performing local clock calibration using the satellite navigation receiver, and acquiring a first pseudorange corresponding to the satellite navigation receiver and the target satellite; disconnecting the antenna under test from the satellite navigation receiver, connecting the satellite navigation receiver's own antenna to the satellite navigation receiver, receiving satellite signals using the own antenna, and acquiring a second pseudorange corresponding to the satellite navigation receiver and the target satellite before the satellite navigation receiver completes local clock calibration; and calculating the delay of the antenna under test using the first pseudorange and the second pseudorange.

[0028] In a specific example, a method for measuring the delay of a satellite navigation antenna using pseudorange is proposed. This method obtains the difference between the satellite pseudorange obtained when the satellite navigation receiver is connected to the antenna under test and the satellite pseudorange obtained when it is connected to its own antenna, and thus obtains the delay difference between the antenna under test and its own antenna.

[0029] In a specific example, when a satellite navigation receiver loses signal lock due to a change in the satellite receiving antenna, it typically maintains the pseudo-code phase it was tracking before the lock loss for a short period to reacquire the signal. For example, in GPS, one pseudo-code chip corresponds to a time of approximately 100 ns. If the antenna change causes a millisecond-level signal delay, maintaining the original pseudo-code phase will prevent signal reacquisition for a short time.

[0030] This embodiment provides a method for measuring the delay of a satellite navigation antenna using pseudorange, which relaxes the requirements for the measurement site and auxiliary testing equipment, and is not limited by the testing site and equipment. This invention is also applicable to scenarios where the satellite antenna is replaced during use. The initial delay of the antenna under test is calculated by the pseudorange difference before and after the antenna replacement. This invention can identify and take measures to shorten the signal reacquisition process in a timely manner, and has real-time performance. This invention can measure a generalized antenna under test using a common single-frequency, single-point positioning receiver, and can obtain millisecond-level delay measurement accuracy.

[0031] In one possible implementation, the first pseudorange corresponding to the target satellite acquired by the satellite navigation receiver includes:

[0032] In the formula, This is the first pseudorange; The local time of the satellite navigation receiver; The time at which satellite signals are transmitted to the target satellite; The time delay is the time delay of the antenna under test; It is the speed of light.

[0033] This embodiment clarifies the mathematical structure and physical meaning of the first pseudorange, clearly defines the superposition relationship of the measured antenna delay in the pseudorange observation value, and provides a rigorous derivation basis for subsequent calculation of antenna delay through pseudorange difference, ensuring the traceability of the measurement principle and the accuracy of the calculation logic.

[0034] In one possible implementation, the second pseudorange corresponding to the target satellite acquired by the satellite navigation receiver includes:

[0035] In the formula, This is the second pseudorange; The local time of the satellite navigation receiver; The time at which satellite signals are transmitted to the target satellite; It is the speed of light.

[0036] This embodiment clarifies the mathematical relationship of the second pseudorange when the antenna is replaced and the receiver is not recalibrated, highlighting the source of pseudorange deviation when the local clock is not corrected, forming a corresponding relationship with the first pseudorange formula, and constructing a complete logical closed loop for the difference method measurement.

[0037] In one possible implementation, calculating the time delay of the antenna under test using the first pseudorange and the second pseudorange includes:

[0038] In the formula, This is the first pseudorange; This is the second pseudorange; The time delay is the time delay of the antenna under test; It is the speed of light.

[0039] In a specific example, the method includes step S1: the satellite navigation receiver connects to the antenna under test, the receiver positions itself and adjusts its local clock, and the positioning process obtains the satellite pseudorange Pr1; Furthermore, the method includes step S2: replacing the antenna under test with the satellite navigation receiver's own antenna, the receiver loses lock and reacquires the signal, and obtains the satellite pseudorange Pr2 before the satellite navigation receiver repositions and adjusts its local clock; Furthermore, the method includes step S3: calculating the delay of the antenna under test, and obtaining the antenna delay = (Pr1-Pr2) / speed of light.

[0040] The key to this embodiment is that before and after replacing the antenna, the satellite navigation receiver is positioned and timed in step S1, while in step S2 the satellite navigation receiver is not timed and the delay of the antenna under test is obtained by measuring the pseudorange difference.

[0041] In a specific example, the calculated antenna delay is used to adjust the receiver's pseudocode search phase range in order to shorten the satellite signal reacquisition time after antenna switching.

[0042] In a specific example, the satellite navigation receiver is a single-frequency single-point positioning receiver, and the measurement process does not require the use of a microwave anechoic chamber, vector network analyzer, GNSS RF signal simulator, time delay transmitter, and calibration reference antenna.

[0043] In a specific example, the method includes: using the antenna under test, a satellite navigation receiver, and the satellite navigation receiver's own antenna, including the following steps: connecting the satellite navigation receiver to the antenna under test, controlling the receiver to complete the positioning calculation and calibrate the local clock, and acquiring the pseudorange Pr1 corresponding to at least one target satellite; disconnecting the antenna under test, replacing it with its own antenna, and within the time window during which the receiver enters a reacquisition state after signal loss due to antenna switching, but before completing repositioning and local clock recalibration, acquiring the pseudorange Pr2 corresponding to the same target satellite; calculating the signal transmission delay of the antenna under test based on the difference between pseudorange Pr1 and pseudorange Pr2.

[0044] This embodiment provides a direct formula for calculating the time delay of the antenna under test, simplifying the antenna delay measurement to the difference calculation of two pseudorange observations. The calculation process has low complexity and strong real-time performance, and can be directly embedded into the firmware logic of the satellite navigation receiver without the need for additional computing power and dedicated computing units.

[0045] In one possible implementation, the signal transmission delay of the antenna itself is less than the signal transmission delay of the antenna under test.

[0046] This embodiment clarifies the selection constraints of the reference terminal's own antenna, ensuring that the interference of the antenna's time delay on the measurement results is within a controllable range, reducing the system error introduced by the reference link, and improving the reliability and stability of the measurement results.

[0047] In one possible implementation, the signal transmission delay of the antenna under test is on the order of milliseconds.

[0048] In a specific example, it is possible to measure the delay of a satellite receiving antenna with delays of 1 millisecond and several milliseconds.

[0049] This embodiment can identify millisecond-level signal delays before and after antenna replacement, which is beneficial for taking measures to shorten the signal reacquisition process.

[0050] This embodiment clarifies the applicable measurement range of the method, accurately adapts to typical high-delay engineering scenarios such as satellite signal forwarding links and anti-interference antenna links, and ensures that the measurement results have practical engineering application value for matching measurement accuracy at the millisecond level.

[0051] In one possible implementation, the signal transmission delay of the self-antenna is on the order of nanoseconds.

[0052] In a specific example, when the delay of the antenna under test reaches 1 millisecond or several milliseconds, since the delay of a normal satellite antenna is on the order of nanoseconds, the antenna delay difference is approximately equal to the delay of the antenna under test.

[0053] In a specific example, the signal transmission delay of the antenna under test is in the millisecond range, while the signal transmission delay of the antenna itself is in the nanosecond range. The transmission delay of the antenna itself is ignored during the calculation.

[0054] This embodiment further quantifies the time delay of the reference antenna to the order of magnitude, making the nanosecond-level self-antenna time delay approximately negligible compared to the millisecond-level measured antenna time delay. While simplifying the calculation model, it ensures that the measurement error is within an acceptable range for engineering purposes, without the need for additional calibration of the reference antenna's own time delay.

[0055] In one possible implementation, the antenna under test is a generalized satellite signal receiving link, including any one of a passive satellite navigation antenna, a satellite signal forwarding link, and an anti-interference antenna signal receiving link.

[0056] In a specific example, the antenna under test is a generalized antenna, which can be a satellite signal forwarding link or an anti-interference antenna signal receiving link.

[0057] This embodiment expands the scope of application of the method, which can not only measure conventional passive satellite navigation antennas, but also cover more generalized antenna scenarios such as active receiving links with signal processing modules and signal forwarding systems, greatly improving the universality and engineering application breadth of the method.

[0058] In one possible implementation, the total duration of the second pseudorange corresponding to the target satellite is less than 5 seconds.

[0059] In a specific example, pseudorange acquisition is completed during the signal loss and reacquisition phase after antenna switching, and the total duration of a single complete measurement is less than 5 seconds.

[0060] In a specific example, the method is implemented during the signal loss process, with a measurement time of less than 5 seconds, demonstrating its speed.

[0061] This embodiment clarifies the time window constraint for the second pseudorange acquisition, ensuring that the acquisition action is completed before the receiver completes local clock recalibration, thus avoiding the disappearance of pseudorange deviation and measurement failure caused by clock correction; at the same time, it ensures the speed of the measurement process, adapting to field application scenarios where antennas switch rapidly.

[0062] Another embodiment of the present invention provides a satellite navigation antenna delay measurement system, the system comprising: a satellite navigation receiver for connecting to an antenna under test, receiving satellite signals using the antenna under test, completing local clock calibration, and acquiring a first pseudorange corresponding to a target satellite; further configured to disconnect the antenna under test, connect its own antenna, receive satellite signals using its own antenna, and acquire a second pseudorange corresponding to the target satellite before completing local clock calibration; and further configured to calculate the delay of the antenna under test using the first pseudorange and the second pseudorange.

[0063] This embodiment provides a satellite navigation antenna delay measurement system using pseudorange, which relaxes the requirements for measurement site and auxiliary testing equipment, and is not limited by the test site and testing equipment. This invention is also applicable to scenarios where satellite antennas are replaced during use. The initial delay of the antenna under test is calculated by the pseudorange difference before and after the antenna replacement. This invention can identify and take measures to shorten the signal reacquisition process in a timely manner, and has real-time performance. This invention can measure a generalized antenna under test using a common single-frequency, single-point positioning receiver, and can obtain millisecond-level delay measurement accuracy.

[0064] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0065] It should also be noted that in the description of this invention, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for measuring the delay of a satellite navigation antenna, characterized in that, The method includes: Connect the antenna under test to the satellite navigation receiver, use the antenna under test to receive satellite signals, use the satellite navigation receiver to perform local clock calibration, and collect the first pseudorange corresponding to the target satellite; Disconnect the antenna under test from the satellite navigation receiver, connect the satellite navigation receiver's own antenna to the satellite navigation receiver, use its own antenna to receive satellite signals, and before the satellite navigation receiver completes local clock calibration, collect the second pseudorange corresponding to the target satellite; The time delay of the antenna under test is calculated using the first pseudorange and the second pseudorange.

2. The satellite navigation antenna delay measurement method according to claim 1, characterized in that, The first pseudorange corresponding to the target satellite and the satellite navigation receiver includes: In the formula, This is the first pseudorange; The local time of the satellite navigation receiver; The time at which satellite signals are transmitted to the target satellite; The time delay is the time delay of the antenna under test; It is the speed of light.

3. The satellite navigation antenna delay measurement method according to claim 2, characterized in that, The second pseudorange corresponding to the target satellite and the satellite navigation receiver acquired includes: In the formula, This is the second pseudorange; The local time of the satellite navigation receiver; The time at which satellite signals are transmitted to the target satellite; It is the speed of light.

4. The satellite navigation antenna delay measurement method according to claim 3, characterized in that, The calculation of the time delay of the antenna under test using the first pseudorange and the second pseudorange includes: In the formula, This is the first pseudorange; This is the second pseudorange; The time delay is the time delay of the antenna under test; It is the speed of light.

5. The satellite navigation antenna delay measurement method according to claim 1, characterized in that, The signal transmission delay of the antenna itself is less than the signal transmission delay of the antenna under test.

6. The satellite navigation antenna delay measurement method according to claim 5, characterized in that, The signal transmission delay of the antenna under test is on the order of milliseconds.

7. The satellite navigation antenna delay measurement method according to claim 6, characterized in that, The signal transmission delay of the antenna itself is on the order of nanoseconds.

8. The satellite navigation antenna delay measurement method according to claim 1, characterized in that, The antenna under test is a generalized satellite signal receiving link, including any one of a passive satellite navigation antenna, a satellite signal forwarding link, or an anti-interference antenna signal receiving link.

9. The satellite navigation antenna delay measurement method according to claim 1, characterized in that, The total duration of the second pseudorange corresponding to the target satellite acquired by the satellite navigation receiver is less than 5 seconds.

10. A satellite navigation antenna delay measurement system, characterized in that, The system includes: A satellite navigation receiver is used to connect to the antenna under test, receive satellite signals using the antenna under test, complete local clock calibration, and acquire the first pseudorange corresponding to the target satellite. It is also used to disconnect the antenna under test, connect its own antenna, and use its own antenna to receive satellite signals. Before completing local clock calibration, it can collect the second pseudorange corresponding to the target satellite. It is also used to calculate the time delay of the antenna under test using the first pseudorange and the second pseudorange.

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