Probe calibration method of multi-probe antenna measurement system

Abstract

The invention provides a probe calibration method for a multi-probe antenna measurement system, and the method comprises the steps: carrying out the measurement of a first amplitude-phase parameter of a first probe located at a target position, enabling at least one probe to move along a preset track, and further measuring a second amplitude-phase parameter of a second probe located at the target position, after amplitude-phase parameter measurement is carried out on the two probes at the same target position, accurate relative amplitude-phase data between the two probes can be obtained according to the measured first amplitude-phase parameter and the measured second amplitude-phase parameter, then accurate calibrated amplitude-phase data of the first probe and the second probe are determined and obtained, accurate calibration of the first probe and the second probe is achieved, and the accuracy of calibration of the two probes is improved. Therefore, the subsequent accurate measurement of the antenna is ensured, the accurate position of the antenna does not need to be calibrated, and errors caused by manual operation (positioning) are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of communications, and in particular to a probe calibration method for a multi-probe antenna measurement system. Background Art

[0002] Calibration is the basis of antenna measurement. The probes, cables, amplifiers, receivers and transmitters of the antenna measurement system all need to be calibrated.

[0003] Especially for antenna measurement systems, it is necessary to use a standard antenna with known gain or known efficiency to place it at the measurement center to calibrate the system path loss. For example, for compact field and far field testing, it is necessary to use a standard antenna placed in a quiet zone for power calibration. For near field testing, it is also necessary to use a standard antenna to calibrate the system phase.

[0004] At present, with the development of technology, many antenna measurement systems adopt the form of multi-probes. Compared with the single-probe measurement system, multi-probes greatly improve the measurement efficiency. The calibration of the multi-probe system requires the use of a standard antenna to calibrate each probe, so as to obtain the power and phase difference information of each probe.

[0005] The multi-probe antenna measurement system has multiple probes, each of which corresponds to a different measurement channel. Different channels correspond to different cables, switches, and even amplifiers. Therefore, channel differences need to be calibrated before testing, otherwise measurement errors will occur. Therefore, the accurate implementation of calibration directly determines whether the measurement system can accurately perform antenna measurements.

[0006] Figure 1 A multi-probe antenna measurement system in the prior art is illustrated. The turntable is located at the center of the multiple probes and is used to carry the object under test and drive it to rotate. The multiple probes are installed on the probe bracket and the multiple probes can move along a preset arc trajectory.

[0007] One calibration method in the prior art is: place the calibration antenna at the center of the measurement system (this center is located on the normal of the turntable, and is also the center of the above-mentioned preset arc trajectory, and is also the position where each probe points), and align the calibration antenna with each probe respectively, measure the amplitude and phase difference of the receive / transmit signal between each probe and the calibration antenna, and complete the calibration of each probe according to the amplitude and phase difference. In this step, there are several ways to align the calibration antenna with each probe respectively. The first is to manually adjust the direction of the calibration antenna on the turntable, assisted by some positioning tools such as lasers, so that the calibration antenna is aligned with the probe. The second is to install the calibration antenna on a rotating device, and the direction of the calibration antenna can be changed by controlling the rotating device to align with each probe. The second calibration method is more mainstream, and the power calibration is more accurate and the error is smaller, but there are the following problems:

[0008] When measuring the amplitude and phase of each probe, the position of the calibration antenna relative to the probe (for example, the distance between the calibration antenna and the probe) will affect the measurement results. This effect is different for power and phase. For example, assuming that the radius of the probe ring (i.e., multiple probes installed in an arc shape on the probe holder) is 5m, when the calibration antenna performs power and phase calibration of different probes, if there is an error of 1cm in the distance between the calibration antenna and different probes, then the error of power calibration is about 20*log10(5.01 / 5)=0.0173dB, which is negligible. However, the effect on phase is quite large. For example, at 6GHz, it is a phase error of 72 degrees, which may cause an error of 288 degrees in the millimeter wave band (such as 24GHz). It can be seen that phase calibration is extremely dependent on the positioning accuracy of the calibration antenna. However, as in the above-mentioned existing calibration methods, whether the calibration antenna is placed manually or the calibration antenna is rotated using a rotating device, it is almost impossible to achieve a consistent distance between the calibration antenna and the probe. Take the example of using a rotating device to rotate the calibration antenna. If you want the calibration antenna to be at equal distances from each probe, the rotation center of the rotating device and the center of the probe ring must be strictly aligned, which is almost impossible to achieve in engineering: first, the center of the probe ring is a virtual position that cannot be found directly and needs to be measured; second, the center of the rotating device is also a virtual position that also needs to be measured, and any measurement will have errors. Aligning the two measured virtual points will introduce large differences in human operations. Therefore, such calibration cannot calibrate the phase difference between different channels.

[0009] See also Figure 2 Another calibration method in the prior art is to use a Dipole antenna or a Loop antenna to calibrate the channel differences between multiple probes. The specific method is to place the Dipole or Loop at the center of the probe ring so that the phase center of the Dipole coincides with the center of the probe ring, and use the consistency of the Dipole phase center to perform calibration. This method also faces problems. The center of the probe ring is a virtual position. How to ensure that the Dipole phase center falls accurately at the center of the probe ring is a challenge, and the phase error caused by the position error increases sharply with the increase of frequency. In addition, due to the existence of common-mode current in the calibration antenna, the phase center cannot be guaranteed to be stable at all times, especially when working at the edge frequency. At this time, a slight deviation in the phase center may also lead to a large phase error.

[0010] In summary, how to accurately calibrate the probes of a multi-probe antenna measurement system is a technical problem that urgently needs to be solved. Summary of the invention

[0011] In view of this, an object of the present invention is to provide a probe calibration method for a multi-probe antenna measurement system, so as to alleviate the technical problem that the prior art cannot accurately calibrate the probes of the multi-probe antenna measurement system.

[0012] In a first aspect, an embodiment of the present invention provides a probe calibration method for a multi-probe antenna measurement system, wherein the multi-probe antenna measurement system comprises: a plurality of probes movable along a preset track, and a test bench for carrying a test piece, wherein the method comprises:

[0013] Measuring a first amplitude and phase parameter between a calibration antenna and a first probe, wherein the calibration antenna is placed on the test bench, and the first probe is a probe located at a target position of the preset track;

[0014] Measuring a second amplitude and phase parameter between the calibration antenna and a second probe, wherein the second probe is a probe located at the target position after at least one of the probes moves along the preset trajectory;

[0015] Relative amplitude and phase data between the first probe and the second probe are determined according to the first amplitude and phase parameters and calibrated amplitude and phase data of the first probe and the second probe are determined based on the relative amplitude and phase data, thereby completing the calibration of the first probe and the second probe.

[0016] Furthermore, the preset trajectory is an arc, and the plurality of probes are distributed along the arc.

[0017] Furthermore, the preset track is a straight line, and the plurality of probes are distributed along the straight line.

[0018] Furthermore, the first probe is adjacent to the second probe.

[0019] Furthermore, there are multiple target locations.

[0020] Furthermore, the first probe is any probe among the multiple probes.

[0021] Furthermore, the number of the target positions is 1.

[0022] Further, determining calibrated amplitude and phase data of the first probe and the second probe based on the relative amplitude and phase data includes:

[0023] Acquire calibrated amplitude and phase data of a first target probe, wherein the first target probe is any one of the first probe and the second probe;

[0024] The calibrated amplitude and phase data of the second target probe are determined according to the relative amplitude and phase data and the calibrated amplitude and phase data of the first target probe, wherein the second target probe is a probe different from the first target probe between the first probe and the second probe.

[0025] Furthermore, the relative positions of the plurality of probes are fixed.

[0026] In an embodiment of the present invention, a probe calibration method for a multi-probe antenna measurement system is provided. The multi-probe antenna measurement system includes: a plurality of probes movable along a preset trajectory, and a test bench for carrying a device under test. The method includes: measuring a first amplitude-phase parameter between a calibration antenna and a first probe, wherein the calibration antenna is placed on the test bench, and the first probe is a probe located at a target position along the preset trajectory; measuring a second amplitude-phase parameter between the calibration antenna and a second probe, wherein the second probe is a probe located at the target position after at least one probe moves along the preset trajectory; determining relative amplitude-phase data between the first probe and the second probe according to the first amplitude-phase parameter and the second amplitude-phase parameter, and determining calibrated amplitude-phase data of the first probe and the second probe based on the relative amplitude-phase data, thereby completing the calibration of the first probe and the second probe. It can be seen from the above description that in the probe calibration method of the multi-probe antenna measurement system of the present invention, after measuring the first amplitude and phase parameters of the first probe located at the target position, the second amplitude and phase parameters of the second probe also located at the target position are further measured by moving at least one probe along a preset trajectory. After the amplitude and phase parameters of the two probes at the same target position are measured, accurate relative amplitude and phase data between the two probes can be obtained based on the measured first amplitude and phase parameters and the second amplitude and phase parameters, and then the accurate calibrated amplitude and phase data of the first probe and the second probe are determined to achieve accurate calibration of the two, thereby ensuring the precise measurement of subsequent antennas. It is no longer necessary to calibrate the precise position of the antenna, thereby avoiding errors caused by human operation (positioning), and alleviating the technical problem that the prior art cannot accurately calibrate the probes of the multi-probe antenna measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 Schematic diagram of the multi-probe calibration system provided for conventional techniques;

[0029] Figure 2A schematic diagram of another multi-probe calibration system provided for conventional techniques;

[0030] Figure 3 A flow chart of a probe calibration method for a multi-probe antenna measurement system provided by an embodiment of the present invention;

[0031] Figure 4 A schematic diagram of a multi-probe antenna measurement system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The existing technology cannot accurately calibrate the probes of a multi-probe antenna measurement system.

[0034] Based on this, in the probe calibration method of the multi-probe antenna measurement system of the present invention, after measuring the first amplitude and phase parameters of the first probe located at the target position, the second amplitude and phase parameters of the second probe also located at the target position are further measured by moving at least one probe along a preset trajectory. After the amplitude and phase parameters of the two probes at the same target position are measured, accurate relative amplitude and phase data between the two probes can be obtained based on the measured first amplitude and phase parameters and the second amplitude and phase parameters, and then the accurate calibrated amplitude and phase data of the first probe and the second probe are determined to achieve accurate calibration of the two, thereby ensuring the precise measurement of subsequent antennas. It is no longer necessary to calibrate the precise position of the antenna, thereby avoiding errors caused by human operation (positioning).

[0035] To facilitate understanding of this embodiment, a probe calibration method for a multi-probe antenna measurement system disclosed in an embodiment of the present invention is first introduced in detail.

[0036] Embodiment 1:

[0037] According to an embodiment of the present invention, an embodiment of a probe calibration method for a multi-probe antenna measurement system is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0038] Figure 3 is a flow chart of a probe calibration method for a multi-probe antenna measurement system according to an embodiment of the present invention. Figure 3 As shown, the method comprises the following steps:

[0039] Step S302, measuring a first amplitude and phase parameter between a calibration antenna and a first probe, wherein the calibration antenna is placed on a test bench, and the first probe is a probe located at a target position of a preset track;

[0040] In an embodiment of the present invention, a multi-probe antenna measurement system includes: a plurality of probes movable along a preset track, and a test bench for carrying a device under test. Figure 4 A schematic diagram of a multi-probe antenna measurement system is shown.

[0041] Specifically, a vector network analyzer may be used to measure the first amplitude and phase parameters between the calibration antenna and the first probe. Figure 4 In the multi-probe antenna measurement system shown, multiple probes are fixedly installed on a ring-shaped probe bracket in relative positions, and the test table (specifically, it can be a turntable for carrying the test piece and driving it to rotate) is located at the center of the multiple probes. The multiple probes can move as a whole along an arc trajectory (for example, along a guide rail), and the center of the arc trajectory is located at the center of the measurement system.

[0042] The above-mentioned target position is a fixed position relative to the calibration antenna. When the probe moves, the position of the target position relative to the calibration antenna is fixed and does not change with the movement of the probe.

[0043] The calibration antenna may be a standard calibration antenna or any other antenna.

[0044] It should be noted that the calibration antenna only needs to be placed on the test bench without aligning it with the probe.

[0045] Step S304, measuring a second amplitude and phase parameter between the calibration antenna and a second probe, wherein the second probe is a probe located at a target position after at least one probe moves along a preset trajectory;

[0046] The inventors took into account that in traditional schemes, attempts are made to place the phase center of the calibration antenna at a virtual position (the center of the probe ring). This virtual position needs to be measured, which results in measurement errors. Moreover, manually aligning the phase center of the calibration antenna with the center of the probe ring (i.e., the virtual position) will introduce large differences in human operation. In addition, the phase center cannot be guaranteed to be stable at all times. All of the above will lead to large phase errors. Based on this, the inventors designed the method of the present invention, which first measures the first amplitude and phase parameters of the first probe located at the target position, and then measures the second amplitude and phase parameters of the second probe also located at the target position by moving at least one probe along a preset trajectory. In this way, accurate relative amplitude and phase data between the two probes at the same target position can be obtained based on the amplitude and phase parameters of the two probes, thereby achieving accurate calibration of the two.

[0047] Step S306, determining relative amplitude and phase data between the first probe and the second probe according to the first amplitude and phase parameter and determining calibrated amplitude and phase data of the first probe and the second probe based on the relative amplitude and phase data, thereby completing the calibration of the first probe and the second probe.

[0048] In an embodiment of the present invention, a probe calibration method for a multi-probe antenna measurement system is provided. The multi-probe antenna measurement system includes: a plurality of probes movable along a preset trajectory, and a test bench for carrying a device under test. The method includes: measuring a first amplitude-phase parameter between a calibration antenna and a first probe, wherein the calibration antenna is placed on the test bench, and the first probe is a probe located at a target position along the preset trajectory; measuring a second amplitude-phase parameter between the calibration antenna and a second probe, wherein the second probe is a probe located at the target position after at least one probe moves along the preset trajectory; determining relative amplitude-phase data between the first probe and the second probe according to the first amplitude-phase parameter and the second amplitude-phase parameter, and determining calibrated amplitude-phase data of the first probe and the second probe based on the relative amplitude-phase data, thereby completing the calibration of the first probe and the second probe. It can be seen from the above description that in the probe calibration method of the multi-probe antenna measurement system of the present invention, after measuring the first amplitude and phase parameters of the first probe located at the target position, the second amplitude and phase parameters of the second probe also located at the target position are further measured by moving at least one probe along a preset trajectory. After the amplitude and phase parameters of the two probes at the same target position are measured, accurate relative amplitude and phase data between the two probes can be obtained based on the measured first amplitude and phase parameters and the second amplitude and phase parameters, and then the accurate calibrated amplitude and phase data of the first probe and the second probe are determined to achieve accurate calibration of the two, thereby ensuring the precise measurement of subsequent antennas. It is no longer necessary to calibrate the precise position of the antenna, thereby avoiding errors caused by human operation (positioning), and alleviating the technical problem that the prior art cannot accurately calibrate the probes of the multi-probe antenna measurement system.

[0049] The above content briefly introduces the probe calibration method of the multi-probe antenna measurement system of the present invention. The specific contents involved therein are described in detail below.

[0050] In an alternative embodiment of the present invention, reference Figure 4 ,The preset trajectory is an arc, and multiple probes are distributed along the arc.

[0051] In an optional embodiment of the present invention, the preset trajectory is a straight line, and multiple probes are distributed along the straight line (for this type of multi-probe antenna measurement system, no corresponding schematic diagram is given, wherein multiple probes are fixedly installed on a linear probe bracket in relative positions).

[0052] In an optional embodiment of the present invention, the first probe is adjacent to the second probe, and the number of the target positions is multiple.

[0053] The following is a specific example to illustrate this calibration method:

[0054] like Figure 4 As shown, when the number of target positions is multiple, the corresponding number of first probes is multiple, and the first probes include: probe B, probe C, probe D, probe E, probe F, probe G and probe H. The positions where the above-mentioned multiple first probes are located are target positions, and the second probes corresponding to the above-mentioned first probes include: probe A, probe B, probe C, probe D, probe E, probe F and probe G.

[0055] When implementing, first use a vector network analyzer to measure Figure 4 Then, the plurality of probes are moved as a whole along the annular probe support so that the plurality of second probes are located at the target positions, that is, probe A reaches the position of probe B, probe B reaches the position of probe C, and so on, and then the second amplitude and phase parameters of probes A, probe B, probe C, probe D, probe E, probe F and probe G are measured at this time; then, the relative amplitude and phase data between probe B and probe A are determined according to the first amplitude and phase parameter of probe B and the second amplitude and phase parameter of probe A, and the relative amplitude and phase data between probe C and probe B are determined according to the first amplitude and phase parameter of probe C and the second amplitude and phase parameter of probe B, and so on, the accurate relative amplitude and phase data between two adjacent probes can be obtained, and if the calibrated amplitude and phase data of probe A is obtained at this time, the data of all probes can be normalized to probe A (normalization is performed by adding the calibrated amplitude and phase data of probe A to the relative amplitude and phase data), and the calibrated amplitude and phase data of all probes are obtained.

[0056] For a straight preset trajectory, the implementation process is similar to the above process and will not be described in detail here.

[0057] In an optional embodiment of the present invention, the first probe is any probe among a plurality of probes, and the number of target positions is one.

[0058] The following is a specific example to illustrate this calibration method:

[0059] like Figure 4 As shown, when the number of target positions is one, the corresponding number of first probes is one. Assuming that the target position is located directly above the calibration antenna, the first probe includes: probe A, the initial position of probe A is the target position, and the second probe includes: probe B, probe C, probe D, probe E, probe F, probe G and probe H.

[0060] When implementing, first use a vector network analyzer to measure Figure 4 Then, the plurality of probes are moved as a whole along the annular probe support so that probe B reaches the initial position (i.e., the target position) of probe A, and the second amplitude and phase parameter of probe B is measured at this time, and the plurality of probes are continued to be moved as a whole along the annular probe support so that probe C reaches the position of probe A, and the second amplitude and phase parameter of probe C is measured at this time, and so on; further, the relative amplitude and phase data between probe B and probe A are determined according to the second amplitude and phase parameter of probe B and the first amplitude and phase parameter of probe A, and the relative amplitude and phase data between probe C and probe A are determined according to the second amplitude and phase parameter of probe C and the second amplitude and phase parameter of probe A, and so on, the accurate relative amplitude and phase data between any other probe and probe A can be obtained, and if the calibrated amplitude and phase data of probe A is obtained at this time, the data of all probes can be normalized to probe A (normalization is performed by adding the calibrated amplitude and phase data of probe A to the relative amplitude and phase data), and the calibrated amplitude and phase data of all probes are obtained.

[0061] For a straight preset trajectory, the implementation process is similar to the above process and will not be described in detail here.

[0062] In an optional embodiment of the present invention, determining the calibrated amplitude and phase data of the first probe and the second probe based on the relative amplitude and phase data specifically includes the following steps:

[0063] (1) obtaining calibrated amplitude and phase data of a first target probe, wherein the first target probe is any one of the first probe and the second probe;

[0064] Specifically, the calibrated amplitude and phase data of the first target probe may be obtained by performing amplitude and phase measurement on the first target probe using a traditional measurement solution.

[0065] (2) determining the calibrated amplitude and phase data of the second target probe according to the relative amplitude and phase data and the calibrated amplitude and phase data of the first target probe, wherein the second target probe is a probe different from the first target probe between the first probe and the second probe.

[0066] In an optional embodiment of the present invention, a probe moving mechanism is used to enable the plurality of probes to move as a whole along the annular probe support.

[0067] Specifically, the plurality of probes move as a whole along the annular probe bracket in the guide rail, that is, a guide rail is provided in the annular probe bracket.

[0068] In an optional embodiment of the present invention, the relative positions of the plurality of probes are fixed.

[0069] The calibration method of the present invention uses the fact that the amplitude and phase parameters (S21) measured by the probes at the same position in the measurement coordinate system should be the same. Based on this, the amplitude and phase are calibrated without having to care about the precise position of the calibration antenna, thus avoiding errors caused by human operation (positioning).

[0070] Probe A and probe B move to the same position. This action only depends on the motion accuracy of the probe motion mechanism. In other words, the mechanical accuracy directly determines the accuracy of the calibration. Compared with the traditional solution of manually placing the calibration antenna so that the probe phase center is at the center of the measurement system (the center of the probe ring), it has better controllability and higher accuracy. Based on the existing industrial foundation, the accuracy of 1um can be achieved through arc or linear guides, and the corresponding error at 24G is only 0.0108 degrees.

[0071] Compared with the traditional method that requires aligning the rotation center (virtual point) of the calibration antenna with the center (virtual point) of the probe ring, the present invention can achieve calibration only by moving the mechanical guide rail, and the calibration accuracy is higher.

[0072] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A probe calibration method for a multi-probe antenna measurement system, characterized in that: The multi-probe antenna measurement system comprises: a plurality of probes movable along a preset track, and a test bench for carrying a test piece. The method comprises: Measuring a first amplitude and phase parameter between a calibration antenna and a first probe, wherein the calibration antenna is placed on the test bench, and the first probe is a probe located at a target position of the preset track; Measuring a second amplitude and phase parameter between the calibration antenna and a second probe, wherein the second probe is a probe located at the target position after at least one of the probes moves along the preset trajectory; Relative amplitude and phase data between the first probe and the second probe are determined according to the first amplitude and phase parameters and calibrated amplitude and phase data of the first probe and the second probe are determined based on the relative amplitude and phase data, thereby completing the calibration of the first probe and the second probe.

2. The method according to claim 1, characterized in that: The preset track is an arc, and the plurality of probes are distributed along the arc.

3. The method according to claim 1, characterized in that The preset track is a straight line, and the plurality of probes are distributed along the straight line.

4. The method according to claim 1, characterized in that: The first probe is adjacent to the second probe.

5. The method according to claim 4, characterized in that The number of the target positions is multiple.

6. The method according to claim 1, characterized in that The first probe is any probe among the plurality of probes.

7. The method according to claim 6, characterized in that The number of the target positions is 1.

8. The method according to claim 1, characterized in that Determining calibrated amplitude and phase data of the first probe and the second probe based on the relative amplitude and phase data includes: Acquire calibrated amplitude and phase data of a first target probe, wherein the first target probe is any one of the first probe and the second probe; The calibrated amplitude and phase data of the second target probe are determined according to the relative amplitude and phase data and the calibrated amplitude and phase data of the first target probe, wherein the second target probe is a probe different from the first target probe between the first probe and the second probe.

9. The method according to claim 1, characterized in that: The relative positions of the plurality of probes are fixed.

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