Method for testing satellite communication performance in high dynamic environment

Abstract

The invention relates to a satellite communication performance test method in a high-dynamic environment, which is characterized in that strict time synchronization between a satellite processor and a terminal is not required through a time-sharing automatic cycle switching design in an uplink and downlink test stage, the problem of time synchronization overhead caused by large transmission delay change in the high-dynamic environment is avoided, a control instruction does not need to be newly added, and the test efficiency is improved. Interaction between the satellite and the terminal is simple and convenient to transplant; through special design of a bidirectional link frame format, coupling transmission of forward link state information, a link configuration instruction and a backward link performance test is realized, and adaptive adjustment of bidirectional link parameter configuration can be supported without assistance of a measurement and control channel. The system testing efficiency and the testing flexibility in a long-distance wireless communication scene are effectively improved, and the testing requirement of a two-way communication link between a satellite and a motion terminal in a high-dynamic scene is fully met.

Description

Technical Field

[0001] The present application relates to the field of satellite communication technology, and in particular, to a method for testing satellite communication performance in a high dynamic environment. Background Art

[0002] In the satellite communication system, a two-way communication link is formed between the satellite and the terminal to transmit control instructions and data information. Before the satellite is officially launched, it is necessary to conduct a system joint test with the terminal, traverse various link parameter configurations, and test and verify the system's connectivity, dynamic range, anti-interference ability and other performance indicators to ensure that all indicators meet the design requirements. As an important evaluation indicator of the joint test, the frame error rate can characterize the link on and off status of the satellite and the terminal under different link parameter configurations, and is the basis and guarantee for the reliable transmission of mission information.

[0003] In order to more realistically and intuitively reflect the actual communication and interconnection status of the link, wireless flight tests are often used between satellites and terminals to simulate the communication link when the satellite is in orbit, that is, the satellite processor is placed on the ground and the terminal is in high-speed motion. In this high-dynamic test environment, the link parameters can only be configured and the link status observed by the host computer on the ground satellite side, and independent real-time testing of the two-way link performance indicators cannot be achieved; at the same time, considering the economic cost of the flight test, it is required to complete the full coverage test of the system indicators in as few flights as possible, and the test process needs to be optimized to improve the test efficiency. In summary, how to achieve satellite communication system performance verification in high-dynamic scenarios has become an urgent problem to be solved. Summary of the invention

[0004] In order to overcome at least one deficiency in the prior art, the present application provides a method for testing satellite communication performance in a high dynamic environment.

[0005] In a first aspect, a method for testing satellite communication performance in a high dynamic environment is provided, comprising:

[0006] Step 1, configure the satellite processor so that the satellite processor is in a state of continuous reception and continuous transmission at the same time after being turned on;

[0007] Configure the relevant parameters of the terminal control unit so that the terminal can perform cyclic switching of the transmit and receive modes after powering on; the relevant parameters of the terminal control unit include the transmit link frame number threshold and the receive mode duration threshold;

[0008] Configure the relevant parameters of the uplink intelligent decision control unit, including the uplink frame error rate index, the terminal receiving signal-to-noise ratio threshold, and the uplink rate gear test list. The satellite transmission rate gears in the uplink rate gear test list are arranged from low to high;

[0009] Configure the relevant parameters of the downlink intelligent decision control unit, including the downlink frame error rate index, the satellite reception signal-to-noise ratio threshold, and the downlink rate gear test list. The terminal transmission rate gears in the downlink speed gear parameter list are arranged from low to high;

[0010] Step 2, powering up the satellite processor and the terminal at the same time to establish a two-way wireless signal transmission link;

[0011] Step 3, perform uplink test phase, including:

[0012] The satellite-side host computer software generates an uplink frame, which is encoded and modulated by the satellite processor and then sent to the terminal; the uplink frame includes the terminal transmission rate gear information; the terminal transmission rate gear information is generated by the downlink intelligent decision control unit according to the downlink rate gear test list; when entering the uplink test phase for the first time, the terminal transmission rate gear information is set to the lowest gear in the downlink speed gear parameter list;

[0013] The uplink intelligent decision control unit configures the satellite transmission rate gear in this uplink test phase according to the uplink rate gear test list; at the same time, while ensuring that the terminal reception signal-to-noise ratio is greater than the terminal reception signal-to-noise ratio threshold and the uplink frame error rate meets the uplink frame error rate index, the uplink channel simulator parameters in this uplink test phase are adaptively and dynamically adjusted to test the maximum tolerable dynamic range and anti-interference capability of the uplink; when the uplink test phase is performed for the first time, the satellite transmission rate gear is set to the lowest gear in the uplink rate gear test list, and the uplink channel simulator parameters are configured to the default values;

[0014] The terminal receives and parses the uplink frame, obtains the terminal transmission rate gear information, performs CRC check on the received uplink frame, counts the total number of received link frames and the total number of correctly checked link frames, calculates the terminal reception signal-to-noise ratio, and completes the uplink status information statistics; at the same time, the terminal sends the received uplink frame and the corresponding timestamp to the data acquisition device for storage;

[0015] Step 4: After the terminal receiving time reaches the receiving mode duration threshold and the current link frame is completely received, the terminal control unit controls the terminal to switch to the transmitting mode to perform a downlink test phase; the downlink test phase includes:

[0016] The terminal generates a downlink frame according to the uplink status information obtained during the uplink test phase, adjusts and encodes the downlink frame, and sends it to the satellite via the transmission channel; and configures the terminal control unit according to the terminal transmission rate gear information obtained;

[0017] The downlink intelligent decision control unit adaptively and dynamically adjusts the parameters of the downlink channel simulator in this downlink test phase, while ensuring that the satellite reception signal-to-noise ratio is greater than the satellite reception signal-to-noise ratio threshold and the downlink frame error rate meets the downlink frame error rate index, so as to test the maximum tolerable dynamic range and anti-interference capability of the downlink; when entering the downlink test phase for the first time, the downlink channel simulator parameters are configured as default values;

[0018] The satellite processor continuously receives downlink frames, demodulates and decodes them, and transmits them to the satellite host computer software; the satellite host computer software parses the uplink status information in the downlink frames and displays it in real time, and calculates the frame error rate in the uplink test phase; the satellite processor calculates the satellite reception signal-to-noise ratio and sends it to the satellite host computer software; the satellite host computer software performs CRC check on the downlink frames, counts the total number of link frames received and the total number of link frames that are correctly checked, calculates the downlink frame error rate, completes the downlink status information statistics and displays it in real time;

[0019] Step 5: After the number of link frames transmitted by the terminal reaches the threshold of the number of link frames transmitted, the terminal control unit controls the terminal to switch to the receiving mode, performs the uplink test phase again, and returns to step 3 until all gears in the uplink rate gear test list and the downlink rate gear test list are tested.

[0020] In one embodiment, the valid data area in the uplink frame includes a satellite transmission link frame count, terminal transmission rate gear information, and a payload;

[0021] The satellite link frame count occupies M bytes, starting from 1. Each time a link frame is sent, the count increases by 1. M must satisfy Among them, T is the total test time, T u is the uplink frame duration, Indicates rounding up;

[0022] The terminal transmission rate gear information occupies 2 bytes;

[0023] The payload is the agreed test data.

[0024] In one embodiment, the valid data area of ​​the downlink frame includes the terminal sending link frame count, the terminal receiving link frame total number, the terminal receiving CRC correct frame total number, the terminal receiving signal-to-noise ratio and the payload;

[0025] The terminal sends a link frame count that occupies N bytes, starting from 1 each time. Each time a link frame is sent, the count increases by 1; N must satisfy 2 8N -1≥X, where X is the threshold of the number of transmission link frames;

[0026] The total number of link frames received by the terminal and the total number of CRC correct frames received by the terminal occupy Q bytes respectively, and Q needs to satisfy Among them, T is the total test time, T u is the uplink frame duration, T t is the duration of the transmission mode, T r is the receiving mode duration threshold; Indicates rounding up;

[0027] The terminal receiving signal-to-noise ratio occupies 2 bytes;

[0028] The payload is the agreed test data.

[0029] Compared with the prior art, this application has the following beneficial effects:

[0030] (1) Through the time-sharing automatic cyclic switching design during the uplink and downlink test phase, there is no need for strict time synchronization between the satellite processor and the terminal, avoiding the time synchronization overhead problem caused by large changes in transmission delay in a high-dynamic environment. No new control instructions are required, and the interaction between the satellite and the terminal is simple, making it easy to transplant.

[0031] (2) Through the special design of the two-way link frame format, the coupled transmission of forward link status information, link configuration instructions and return link performance test is realized, which can support the adaptive adjustment of two-way link parameter configuration without the assistance of measurement and control channels, effectively improving the system test efficiency and test flexibility in long-distance wireless communication scenarios, and fully meeting the two-way communication link test requirements between satellites and moving terminals in high dynamic scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present application may be better understood by referring to the following description given in conjunction with the accompanying drawings, which together with the following detailed description are included in this specification and form a part of this specification. In the drawings:

[0033] Figure 1 A schematic diagram of a satellite communication performance test system is shown;

[0034] Figure 2 A schematic diagram of an uplink frame format is shown;

[0035] Figure 3 A schematic diagram of the downlink frame format is shown. DETAILED DESCRIPTION

[0036] The exemplary embodiments of the present application will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual embodiments are described in the specification. However, it should be understood that many implementation-specific decisions can be made in the process of developing any such actual embodiments in order to achieve the specific goals of the developer, and these decisions may vary from embodiment to embodiment.

[0037] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure closely related to the scheme according to the present application is shown in the drawings, while other details that are not closely related to the present application are omitted.

[0038] It should be understood that the present application is not limited to the described implementation forms due to the following description with reference to the accompanying drawings. In this article, where feasible, the embodiments can be combined with each other, features between different embodiments can be replaced or borrowed, and one or more features can be omitted in one embodiment.

[0039] An embodiment of the present application provides a method for testing satellite communication performance in a high dynamic environment. For ease of description, an uplink is defined as a wireless communication link sent by a satellite and received by a terminal, and a downlink is defined as a wireless communication link sent by a terminal and received by a satellite. Figure 1 A schematic diagram of a satellite communication performance test system is shown in FIG. Figure 1 , the methods mainly include:

[0040] Step 1, configure the satellite processor so that the satellite processor is in a state of continuous reception and continuous transmission at the same time after being turned on;

[0041] Configure the relevant parameters of the terminal control unit so that the terminal can switch between the transmit and receive modes cyclically after startup, and set the terminal to be in the receive mode initially after startup; the relevant parameters of the terminal control unit include the transmit link frame number threshold X and the receive mode duration threshold T r ;

[0042] Assume that the total test duration is T and the uplink frame duration is T u , the downlink frame duration is T d , then the emission mode duration T t Satisfy X·T d =T t , the receiving mode duration reaches the threshold T r After that, it is necessary to ensure that the entire frame of data is received completely before switching to the transmission mode, so the actual receiving mode duration is T r +ε, where ε is a parameter to ensure that the entire frame of data is received completely, and ε satisfies 0≤ε <T u ; Set the terminal to be in receiving mode initially after powering on.

[0043] Configure the relevant parameters of the uplink intelligent decision control unit, including the uplink frame error rate index, the terminal receiving signal-to-noise ratio threshold, and the uplink rate gear test list. The satellite transmission rate gears in the uplink rate gear test list are arranged from low to high;

[0044] Configure the relevant parameters of the downlink intelligent decision control unit, including the downlink frame error rate indicator, the satellite reception signal-to-noise ratio threshold, and the downlink rate gear test list. The terminal transmission rate gears in the downlink speed gear parameter list are arranged from low to high.

[0045] Step 2: Power on the satellite processor and the terminal at the same time to establish a two-way wireless signal transmission link.

[0046] Step 3, performing uplink testing, including:

[0047] First, adjust the satellite transmission channel parameters and the uplink channel simulator parameters, and combine the terminal motion state to simulate the high dynamic scene required for the actual task, while ensuring that the terminal's receiving level is within the normal working range; here, adjust the satellite transmission channel parameters and the uplink channel simulator parameters according to the size of the terminal's receiving level.

[0048] The satellite-side host computer software generates an uplink frame, which is encoded and modulated by the satellite processor and then sent to the terminal; the uplink frame includes the terminal transmission rate gear information; the terminal transmission rate gear information is generated by the downlink intelligent decision control unit according to the downlink rate gear test list; when entering the uplink test phase for the first time, the terminal transmission rate gear information is set to the lowest gear in the downlink speed gear parameter list;

[0049] Specifically, Figure 2 shows a schematic diagram of the uplink frame format, see Figure 2 , the valid data area in the uplink frame includes the satellite transmission link frame count, the terminal transmission rate gear information and the payload;

[0050] The satellite link frame count occupies M bytes, starting from 1, and increases by 1 each time a link frame is sent. To ensure that the data bytes do not overflow, M must satisfy Among them, T is the total test time, T u is the uplink frame duration;

[0051] The terminal transmission rate gear information occupies 2 bytes;

[0052] The payload is the agreed test data.

[0053] The uplink intelligent decision control unit configures the satellite transmission rate gear in this uplink test phase according to the uplink rate gear test list; at the same time, while ensuring that the terminal reception signal-to-noise ratio is greater than the terminal reception signal-to-noise ratio threshold and the uplink frame error rate meets the uplink frame error rate index, the uplink channel simulator parameters in this uplink test phase are adaptively and dynamically adjusted, including delay, frequency deviation, signal-to-interference ratio, etc., to test the maximum tolerable dynamic range and anti-interference capability of the uplink; when the uplink test phase is performed for the first time, the satellite transmission rate gear is set to the lowest gear in the uplink rate gear test list, and the uplink channel simulator parameters are configured as default values;

[0054] Here, in the process of adjusting the parameters of the uplink channel simulator, it is determined that when the terminal received signal-to-noise ratio is greater than the terminal received signal-to-noise ratio threshold and the uplink frame error rate meets the uplink frame error rate indicator, the adjustment range of the parameters of the uplink channel simulator is the maximum tolerable dynamic range and anti-interference capability of the uplink.

[0055] The terminal receives and parses the uplink frame, obtains the terminal transmission rate gear information, performs CRC check on the received uplink frame, counts the total number of link frames received and the total number of link frames with correct check, calculates the terminal reception signal-to-noise ratio, and completes the uplink status information statistics; at the same time, the terminal sends the received uplink frame and the corresponding timestamp to the data acquisition device for storage.

[0056] Step 4: After the terminal receiving time reaches the receiving mode duration threshold and the current link frame is completely received, the terminal control unit controls the terminal to switch to the transmitting mode to perform a downlink test phase; the downlink test phase includes:

[0057] First, adjust the satellite receiving channel parameters and the downlink channel simulator parameters, and combine the terminal motion state to simulate the high dynamic scene required for the actual mission, while ensuring that the satellite's receiving level is within the normal working range.

[0058] The terminal generates a downlink frame according to the uplink status information obtained during the uplink test phase, adjusts and encodes the downlink frame, and sends it to the satellite via the transmission channel; and configures the terminal control unit according to the terminal transmission rate gear information obtained;

[0059] Specifically, Figure 3 A schematic diagram of the downlink frame format is shown in FIG. Figure 3 , the valid data area of ​​the downlink frame includes the terminal sending link frame count, the terminal receiving link frame total number, the terminal receiving CRC correct frame total number, the terminal receiving signal-to-noise ratio and payload;

[0060] The terminal sends a link frame count that occupies N bytes, starting from 1 each time. The count increases by 1 each time a link frame is sent. To ensure that the data bytes do not overflow, N must satisfy 2. 8N -1≥X, where X is the threshold of the number of transmission link frames;

[0061] The total number of link frames received by the terminal and the total number of CRC correct frames received by the terminal occupy Q bytes respectively, and Q needs to satisfy Among them, T is the total test time, T u is the uplink frame duration, T t is the duration of the transmission mode, T r is the receiving mode duration threshold;

[0062] The terminal receiving signal-to-noise ratio occupies 2 bytes;

[0063] The payload is the agreed test data.

[0064] The downlink intelligent decision control unit adaptively and dynamically adjusts the parameters of the downlink channel simulator in this downlink test phase, while ensuring that the satellite reception signal-to-noise ratio is greater than the satellite reception signal-to-noise ratio threshold and the downlink frame error rate meets the downlink frame error rate index, so as to test the maximum tolerable dynamic range and anti-interference capability of the downlink; when entering the downlink test phase for the first time, the downlink channel simulator parameters are configured as default values;

[0065] Here, in the process of adjusting the parameters of the downlink channel simulator, it is determined that when the satellite reception signal-to-noise ratio is greater than the satellite reception signal-to-noise ratio threshold and the downlink frame error rate meets the downlink frame error rate indicator, the adjustment range of the parameters of the downlink channel simulator is the maximum dynamic range and anti-interference capability that the downlink can tolerate.

[0066] The satellite processor continuously receives downlink frames, demodulates and decodes them, and transmits them to the satellite host computer software; the satellite host computer software parses the uplink status information in the downlink frames and displays it in real time, and calculates the frame error rate in the uplink test phase; the satellite processor calculates the satellite reception signal-to-noise ratio and sends it to the satellite host computer software; the satellite host computer software performs CRC check on the downlink frames, counts the total number of link frames received and the total number of link frames that are correctly checked, calculates the downlink frame error rate, completes the downlink status information statistics and displays it in real time; the calculation method is as follows:

[0067]

[0068] Step 5: After the number of link frames transmitted by the terminal reaches the threshold of the number of link frames transmitted, the terminal control unit controls the terminal to switch to the receiving mode, performs the uplink test phase again, and returns to step 3 until all gears in the uplink rate gear test list and the downlink rate gear test list are tested.

[0069] Here, after completing the maximum dynamic range and anti-interference capability index test of the current uplink rate gear, the uplink intelligent decision-making control unit switches the satellite transmission rate gear configuration according to the uplink rate gear test list; after completing the maximum dynamic range and anti-interference capability index test of the current downlink rate gear, the downlink intelligent decision-making control unit switches the terminal transmission rate gear configuration according to the downlink rate gear test list; the test ends after completing the index test of all rate gears in sequence.

[0070] After the test is completed, the test data and corresponding receiving timestamp stored in the data acquisition device can be read, and combined with the terminal motion trajectory and the scenario simulated by the channel simulator, a specific analysis can be made on the changes in the uplink status as the terminal motion status changes.

[0071] In summary, compared with the prior art, this application has the following technical effects:

[0072] (1) Through the time-sharing automatic cyclic switching design during the uplink and downlink test phase, there is no need for strict time synchronization between the satellite processor and the terminal, avoiding the time synchronization overhead problem caused by large changes in transmission delay in a high-dynamic environment. No new control instructions are required, and the interaction between the satellite and the terminal is simple, making it easy to transplant.

[0073] (2) Through the special design of the two-way link frame format, the coupled transmission of forward link status information, link configuration instructions and return link performance test is realized, which can support the adaptive adjustment of two-way link parameter configuration without the assistance of measurement and control channels, effectively improving the system test efficiency and test flexibility in long-distance wireless communication scenarios, and fully meeting the two-way communication link test requirements between satellites and moving terminals in high dynamic scenarios.

[0074] The above are only various implementations of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for testing satellite communication performance in a high dynamic environment, characterized in that: include: Step 1, configuring the satellite processor so that the satellite processor is in a state of continuous reception and continuous transmission at the same time after being turned on; Configure the relevant parameters of the terminal control unit so that the terminal can cyclically switch between the sending and receiving modes after powering on; The relevant parameters of the terminal control unit include a transmission link frame number threshold and a receiving mode duration threshold; Configure relevant parameters of the uplink intelligent decision control unit, the relevant parameters including uplink frame error rate index, terminal reception signal-to-noise ratio threshold, uplink rate gear test list, the satellite transmission rate gear in the uplink rate gear test list is arranged from low to high; Configure relevant parameters of the downlink intelligent decision control unit, the relevant parameters including downlink frame error rate index, satellite reception signal-to-noise ratio threshold, downlink rate gear test list, and the terminal transmission rate gear in the downlink speed gear parameter list is arranged from low to high; Step 2, powering on the satellite processor and the terminal simultaneously to establish a two-way wireless signal transmission link; Step 3, performing uplink testing, including: The satellite-side host computer software generates an uplink frame, which is encoded and modulated by the satellite processor and then sent to the terminal; the uplink frame includes terminal transmission rate gear information; the terminal transmission rate gear information is generated by the downlink intelligent decision control unit according to the downlink rate gear test list; when entering the uplink test phase for the first time, the terminal transmission rate gear information is set to the lowest gear in the downlink speed gear parameter list; The uplink intelligent decision control unit configures the satellite transmission rate gear in this uplink test phase according to the uplink rate gear test list; at the same time, while ensuring that the terminal reception signal-to-noise ratio is greater than the terminal reception signal-to-noise ratio threshold and the uplink frame error rate meets the uplink frame error rate index, adaptively and dynamically adjusts the parameters of the uplink channel simulator in this uplink test phase to test the maximum tolerable dynamic range and anti-interference capability of the uplink; when the uplink test phase is performed for the first time, the satellite transmission rate gear is set to the lowest gear in the uplink rate gear test list, and the uplink channel simulator parameters are configured as default values; The terminal receives and parses the uplink frame, obtains the terminal transmission rate gear information, performs CRC check on the received uplink frame, counts the total number of received link frames and the total number of correctly checked link frames, calculates the terminal reception signal-to-noise ratio, and completes uplink status information statistics; at the same time, the terminal sends the received uplink frame and the corresponding timestamp to the data acquisition device for storage; Step 4: After the terminal receiving time reaches the receiving mode duration threshold and the current link frame is completely received, the terminal control unit controls the terminal to switch to the transmitting mode to perform a downlink test phase; the downlink test phase includes: The terminal generates a downlink frame according to the uplink state information obtained in the uplink test phase, and adjusts and encodes the downlink frame and sends it to the satellite through the transmission channel; and configures the terminal control unit according to the acquired terminal transmission rate gear information; The downlink intelligent decision control unit adaptively and dynamically adjusts the parameters of the downlink channel simulator in this downlink test phase, while ensuring that the satellite reception signal-to-noise ratio is greater than the satellite reception signal-to-noise ratio threshold and the downlink frame error rate meets the downlink frame error rate index, so as to test the maximum dynamic range and anti-interference capability that the downlink can tolerate; when entering the downlink test phase for the first time, the downlink channel simulator parameters are configured as default values; The satellite processor continuously receives the downlink frame, demodulates and decodes it, and transmits it to the satellite host computer software; the satellite host computer software parses the uplink status information in the downlink frame and displays it in real time, and calculates the frame error rate of the uplink test phase; the satellite processor calculates the satellite reception signal-to-noise ratio and sends it to the satellite host computer software; the satellite host computer software performs CRC check on the downlink frame, counts the total number of link frames received and the total number of link frames that are correctly checked, calculates the downlink frame error rate, completes the downlink status information statistics and displays it in real time; Step 5: After the number of link frames transmitted by the terminal reaches the threshold of the number of link frames transmitted, the terminal control unit controls the terminal to switch to the receiving mode, performs the uplink test phase again, and returns to step 3 until all gears in the uplink rate gear test list and the downlink rate gear test list are tested.

2. The method according to claim 1, characterized in that in, The valid data area in the uplink frame includes a satellite transmission link frame count, terminal transmission rate gear information and payload; The satellite link frame count occupies M bytes, starting from 1, and the count increases by 1 each time a link frame is sent; M must satisfy Among them, T is the total test time, T u is the uplink frame duration, Indicates rounding up; The terminal transmission rate gear information occupies 2 bytes; The payload is the agreed test data.

3. The method according to claim 1, characterized in that The valid data area of ​​the downlink frame includes a terminal sending link frame count, a terminal receiving link frame total number, a terminal receiving CRC correct frame total number, a terminal receiving signal-to-noise ratio and a payload; The terminal sends a link frame count that occupies N bytes, starting from 1 each time, and the count increases by 1 each time a link frame is sent; N must satisfy 2 8N -1≥X, where X is the threshold of the number of transmission link frames; The total number of link frames received by the terminal and the total number of CRC correct frames received by the terminal occupy Q bytes respectively, and Q needs to satisfy Among them, T is the total test time, T u is the uplink frame duration, T t is the duration of the transmission mode, T r is the receiving mode duration threshold; Indicates rounding up; The terminal receiving signal-to-noise ratio occupies 2 bytes; The payload is the agreed test data.

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