A method for threshold adjustment of an on-board space CCD detector array
By using a satellite-to-ground communication link and a lookup table, the threshold of the CCD detector array is adjusted in real time, solving the problem of low efficiency in traditional methods and achieving high-efficiency, real-time detection accuracy and data processing efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2023-09-08
- Publication Date
- 2026-06-23
AI Technical Summary
In existing technologies, inappropriate threshold settings for space CCD detector arrays can lead to data loss or waste. Traditional adjustment methods are inefficient, time-consuming, and labor-intensive, and cannot achieve high-efficiency, real-time detection accuracy.
The detector's operating threshold is adjusted in real time through steps including temperature range acquisition, data downlink, lookup table establishment, data uplink, and threshold adjustment. Efficient and real-time threshold adjustment is achieved using the space-to-ground communication link and lookup table.
It enables efficient, real-time threshold adjustment of the on-board CCD detector array, improving detection accuracy and data processing efficiency, and reducing the generation of invalid data.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of nuclear technology, and more specifically to a method for adjusting the threshold of an on-board space CCD detector array, which is particularly suitable for space exploration. Background Technology
[0002] In space science exploration using X-ray CCD detector arrays, the complex space environment and numerous factors cause fluctuations in detector operating temperature, leading to changes in the detector's operating threshold. An inappropriate threshold setting for any detector can cause problems in space experiments. If the threshold is set too high, all data below the threshold will be lost, making it impossible to observe the target. If the threshold is set too low, the data volume will increase, wasting satellite storage space and downlink bandwidth, causing invalid data to clog the link, and potentially losing valid observation data. Therefore, it is necessary to modify the detector's threshold. The conventional approach is that if a detector's operating threshold is found to be unsuitable during ground data processing, a command is sent to the satellite, which then forwards the command to the payload to modify the detector's threshold. The modified threshold is then analyzed and verified after data is downlinked. If multiple detectors' operating thresholds are found to have changed, multiple commands are sent to modify the thresholds. Because satellites can only send commands when they pass over my country, to verify the results, we need to wait for the satellite to pass over again and transmit data. If multiple commands are sent to modify the threshold, the waiting time will be even longer. Moreover, the temperature fluctuations caused by the space environment are a continuous process, requiring constant modification of the threshold. The traditional approach is inefficient, time-consuming, laborious, and ineffective, making it very inconvenient to use.
[0003] The beneficial effects of this invention are: it can efficiently and in real time complete the threshold adjustment of the on-board space CCD detector array in a simple way, thereby allowing high detection accuracy to be achieved. Summary of the Invention
[0004] To address the aforementioned problems in the prior art, this invention discloses a threshold adjustment method for an on-board CCD detector array, which can efficiently and in real-time adjust the threshold of the on-board CCD detector array in a simple manner, thereby allowing for high detection accuracy.
[0005] Specifically, the on-board space CCD detector array threshold adjustment method of the present invention may include a temperature range acquisition step, a data downlink step, a lookup table establishment step, a data uplink step, and a threshold adjustment step.
[0006] The temperature range acquisition step is used to obtain the operating temperature range R of each detector module i in the on-board CCD detector array. i ;
[0007] The data downlink step is used to transmit the operating temperature range R via a satellite-to-ground communication link. i Download to ground station;
[0008] The lookup table creation step is used to calculate the operating temperature range R by the ground station. i Multiple operating temperatures T within ij The corresponding detector's optimal operating threshold Tr ij Establish operating temperature T ij and the detector's optimal operating threshold Tr ij lookup table C i ;
[0009] The data upload step is used to transmit the query table C via a satellite-to-ground communication link. i Uploaded to satellite;
[0010] The threshold adjustment step is used to obtain the real-time operating temperature Tr of detector module i from the satellite. i And based on the real-time operating temperature Tr i From query table C i Obtain the optimal operating threshold Tr of the detector ij And set it as the working threshold of detector module i.
[0011] Furthermore, the on-board space CCD detector array is a soft X-ray detector.
[0012] Preferably, in the temperature range acquisition step, the operating temperature range R is determined based on the operating temperature of detector module i collected within a preset time. i .
[0013] Furthermore, in the query table creation step, according to Operating temperature range R i Convert to N hexadecimal numbers x ij The array consists of j = 1, ..., N, and the lookup table C i Operating temperature T ij From hexadecimal number x ij express.
[0014] Furthermore, in the query table creation step, each query table C will also be... i Merge into a single lookup table C, and calculate the checksum H of lookup table C. c And configure the identifier for query table C in query table C. i Header ID i .
[0015] Furthermore, in the data upload step, the query table C is split into multiple data blocks DB with preset sizes. kCalculate data block DB k Check code H k and the data block DB k and its check code H k Uploaded to the satellite; and the satellite calculates the received data block DB. k The system retrieves the checksum and compares it with the received checksum. If they do not match, it notifies the user to re-upload the data block DB. k .
[0016] Furthermore, in the data upload step, the checksum of the received query table C is calculated and compared with the received checksum H. c Compare them.
[0017] Furthermore, the on-board space CCD detector array threshold adjustment method also includes the step of sending an automatic threshold adjustment command to the satellite.
[0018] Furthermore, upon receiving the automatic threshold adjustment instruction, the threshold adjustment step is executed.
[0019] Preferably, the preset time in the temperature range acquisition step is one or several months. Detailed Implementation
[0020] In the following, exemplary embodiments of the present invention will be described in detail. The following embodiments are provided by way of example in order to fully convey the spirit of the invention to those skilled in the art. Therefore, the invention is not limited to the embodiments disclosed herein.
[0021] The Low Energy X-ray Telescope (LE) is a subsystem of the Insight-HXMT payload subsystem. Its basic function is to conduct sky surveys and fixed-point observations in the soft X-ray (1.0–15 keV) energy range. The LE uses a detector array composed of 96 CCD detectors. For ease of installation, every four detectors are integrated onto a base module, forming a detector module i, where i is 1, …, 24.
[0022] This invention uses LE as an example to describe the threshold adjustment method of the on-board space CCD detector array. In order to improve the efficiency of LE scientific observation, the thresholds of all detectors can be automatically adjusted on-board.
[0023] The on-board space CCD detector array threshold adjustment method according to the present invention may include a temperature range acquisition step, a data downlink step, a lookup table establishment step, a data uplink step, and a threshold adjustment step.
[0024] Due to factors such as satellite orbit, inclination, Earth's radiation, and the space environment, the on-orbit operating temperature of a CCD detector cannot be precisely controlled within a small range and will fluctuate to some extent. Simulations and actual measurements have shown that the on-orbit operating temperature of LE's CCD detector array ranges from -30℃ to -80℃, with some regularity in the fluctuations, but it is not entirely predictable. Therefore, in this invention, a temperature range acquisition step can be used to obtain the actual operating temperature range R of detector i by collecting detector temperature data over a preset relatively long period (at least one month). i .
[0025] Specifically, a temperature detector can be integrated into a single detector module i, and the temperature it measures is the actual operating temperature of the four detectors in detector module i, as shown in Table 1. In this case, LE has a total of 24 temperature detectors.
[0026] Table 1 Correspondence between detector channels and temperature detectors
[0027]
[0028]
[0029] The operating temperature range R of each detector module i in the on-board CCD detector array is obtained in LE. i Then, the operating temperature range R can be transmitted via a satellite-to-ground communication link using the data downlink step. i Download to the ground station.
[0030] Subsequently, the ground station can calculate the operating temperature range R. i Multiple operating temperatures T within ij The corresponding detector's optimal operating threshold Tr ij Establish operating temperature T ij and the detector's optimal operating threshold Tr ij lookup table C i The operating temperature values can completely cover the range of temperature fluctuations that may occur on the satellite.
[0031] Specifically, the ground station can... Operating temperature range R i Convert to N hexadecimal numbers x ij The array consists of j = 1, ..., N, and the lookup table C i Operating temperature T ij From hexadecimal number x ij This indicates that, for example, the operating temperature range of a CCD detector is -80℃ to -30℃, which corresponds to 0x000 to 0xfff in hexadecimal.
[0032] Table 2 Single Detector Module Lookup Table Ci
[0033]
[0034]
[0035] After obtaining the lookup table C for each detector module i i After that, you can also combine the various query tables C i The results are merged into a single lookup table C, as shown in Table 2, and the checksum H of lookup table C is calculated. c And configure the identifier for query table C in query table C. i Header ID i Distinguish the identifiers of different detector modules within the table.
[0036] The data upload step is used by the ground station to transmit the query table C via the satellite-to-ground communication link. i Uploaded to the satellite.
[0037] Therefore, the ground station can split the query table C into multiple data blocks DB with a preset size (e.g., 1 kbits). k Calculate data block DB k Check code H k Then, the data blocks DB are transmitted one by one via a ground antenna. k and its check code H k Uploaded to the satellite.
[0038] After receiving the uploaded data, the satellite LE needs to calculate the received data block DB. k The system retrieves the verification code and compares it with the received verification code. If they do not match, it notifies the user to re-upload the data block DB. k Similarly, uploading the entire query table C would require approximately 3 to 4 orbits, and considering that there are other operations performed each time the satellite passes over, the upload process will also be completed within one day.
[0039] After the satellite receives the lookup table C, it can store it in the EEPROM of LE Electronics. It can also use LE's read function to repeatedly verify the checksum of the uploaded data to confirm the correctness of the uploaded and stored lookup table.
[0040] After uploading lookup table C to the satellite, the ground station can send an automatic threshold adjustment command to the satellite.
[0041] After receiving the automatic threshold adjustment command, the satellite can obtain the real-time operating temperature Tr of detector module i during the threshold adjustment step. i And based on the real-time operating temperature Tr i From query table C iObtain the optimal operating threshold Tr of the detector ij And set it as the working threshold of detector module i.
[0042] For example, LE Electronics stores the current operating temperatures of the 24 CCD modules in memory in real time and calculates the corresponding temperature range number. LE's software queries the temperature range number in memory every 64 seconds and compares it with the previously calculated range. If a change is detected in the temperature range of a detector module, an internal command is generated to modify the detector threshold of that module, achieving real-time on-board adjustment. This function can be disabled by sending a command from the ground, allowing for manual threshold modification.
[0043] Furthermore, long-term radiation from the space environment may cause CCD detector performance degradation. It is necessary to regenerate the temperature threshold table based on the test results and repeat the above-mentioned threshold adjustment method for on-board CCD detector array.
[0044] In summary, by using the threshold adjustment method for on-board CCD detector arrays of the present invention, the threshold adjustment of on-board CCD detector arrays can be completed efficiently and in real time in a simple manner, thereby allowing for high detection accuracy.
[0045] Although the present invention has been described above with reference to specific embodiments, those skilled in the art will readily recognize that the above embodiments are merely exemplary and used to illustrate the principles of the present invention. They do not limit the scope of the present invention. Those skilled in the art can make various combinations, modifications and equivalent substitutions to the above embodiments without departing from the spirit and scope of the present invention.
Claims
1. A method for threshold adjustment of an on-board CCD detector array, comprising a temperature range acquisition step, a data downlink step, a lookup table establishment step, a data uplink step, and a threshold adjustment step; The temperature range acquisition step is used to obtain the operating temperature range R of each detector module i in the on-board CCD detector array. i ; The data downlink step is used to transmit the operating temperature range R via a satellite-to-ground communication link. i Download to the ground station; The lookup table creation step is used to calculate the operating temperature range R by the ground station. i Multiple operating temperatures T within ij The corresponding detector's optimal operating threshold Tr ij Establish operating temperature T ij and the detector's optimal operating threshold Tr ij lookup table C i ; The data upload step is used to transmit the query table C via a satellite-to-ground communication link. i Uploaded to satellite; The threshold adjustment step is used to obtain the real-time operating temperature Tr of detector module i from the satellite. i And based on the real-time operating temperature Tr i From query table C i Obtain the optimal operating threshold Tr of the detector ij And set it as the working threshold of detector module i.
2. The threshold adjustment method for an on-board CCD detector array as described in claim 1, wherein, The on-board CCD detector array is a soft X-ray detector.
3. The threshold adjustment method for an on-board CCD detector array as described in claim 1, wherein, In the temperature range acquisition step, the operating temperature range R is determined based on the operating temperature of detector module i collected within a preset time period. i .
4. The threshold adjustment method for an on-board CCD detector array as described in claim 1, wherein, In the query table creation step, according to Operating temperature range R i Convert to N hexadecimal numbers x ij The array consists of j = 1, ..., N, and the lookup table C i Operating temperature T ij From hexadecimal number x ij express.
5. The threshold adjustment method for an on-board CCD detector array as described in claim 1, wherein, In the query table creation step, each query table C will also be... i Merge into a single lookup table C, and calculate the checksum H of lookup table C. c And configure the identifier for query table C in query table C. i Header ID i .
6. The threshold adjustment method for an on-board CCD detector array as described in claim 5, wherein, In the data upload step, the query table C is split into multiple data blocks DB with preset sizes. k Calculate data block DB k Check code H k and the data block DB k and its check code H k Uploaded to the satellite; and the satellite calculates the received data block DB. k The system retrieves the checksum and compares it with the received checksum. If they do not match, it notifies the user to re-upload the data block DB. k .
7. The threshold adjustment method for an on-board CCD detector array as described in claim 6, wherein, In the data upload step, the checksum of the received query table C is also calculated and compared with the received checksum H. c Compare them.
8. The on-board space CCD detector array threshold adjustment method as described in claim 1, further comprising the step of sending an automatic threshold adjustment command to the satellite.
9. The threshold adjustment method for an on-board CCD detector array as described in claim 1, wherein, Upon receiving the automatic threshold adjustment instruction, the threshold adjustment steps are executed.
10. The threshold adjustment method for an on-board CCD detector array as described in claim 3, wherein, The preset time for obtaining the temperature range is one or several months.