Satellite communication data transmission system and method for water conservancy monitoring

Abstract

The invention discloses a satellite communication data transmission system and method for water conservancy monitoring, and relates to the technical field of satellite communication data transmission, and the method comprises the steps: determining the time length of a satellite visible window when a satellite module enters a communicable state, obtaining a link quality index sequence in the window, and reading a power supply voltage and a window available energy budget; performing window integral estimation on each transmission mode based on the mode table to obtain a window average single packet success probability; the method comprises the following steps: forming a sending block by dequeuing basic segment messages from a to-be-sent queue preferentially according to a validity period, determining a target delivery probability of the sending block, generating a check packet through single check block coding under the constraint of a window average single packet success probability, determining a minimum packet size meeting the target delivery probability, calculating energy consumption, and selecting an execution mode, and sending the basic segment message and the check packet in sequence. The timeliness distinguishing and the delivery target constraint of the water message are realized, and the stability and the verifiability of reliable delivery are improved under the available energy budget constraint.

Description

Technical Field

[0001] This invention relates to the field of satellite communication data transmission technology, and in particular to a satellite communication data transmission system and method for water conservancy monitoring. Background Technology

[0002] Water conservancy monitoring targets scenarios such as rivers, reservoirs, and dams. It typically relies on on-site monitoring terminals to periodically collect hydrological data such as water levels and uploads it to the operational platform via communication links to support scheduling and early warning. In remote mountainous areas, reservoir areas, and environments with insufficient terrestrial network coverage, such as emergency disaster areas, satellite communication has become a commonly used remote backhaul method due to its wide coverage, flexible deployment, and strong resistance to environmental disturbances. Existing solutions are mostly designed around stable transmission within the visible window, combining wireless parameter configurations such as link quality indicators, modulation coding, and transmission power, and with reliability mechanisms such as forward error correction or retransmission confirmation, to achieve continuous reporting and traceable recording of water information messages under limited bandwidth and power supply conditions.

[0003] Given the timeliness of water conservancy monitoring operations and the intermittent nature of satellite visibility windows, conventional methods mainly suffer from several drawbacks. Water information messages are often reported on a fixed schedule and use a first-come, first-served or coarse-grained priority approach, making it difficult to translate water level deviations and trends into actionable delivery targets and validity constraints. This results in difficulties in differentiating between emergency water conditions and routine sampling when resources are limited. Link adaptation often relies on static thresholds or single-point link indicators, lacking a success probability assessment based on visible window link quality sequences and a threshold calibration mechanism driven by feedback. Consequently, the launch mode and redundancy configuration are difficult to adaptively converge to a verifiable reliability level with respect to the window link and energy budget. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a satellite communication data transmission method for water conservancy monitoring to solve the problems of water information messages lacking delivery targets and validity guarantee mechanisms based on water level changes, and link adaptation lacking window probability assessment and feedback calibration mechanisms under satellite visibility window and energy-limited conditions.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a satellite communication data transmission method for water conservancy monitoring, which includes: collecting measured water level values ​​to form a sampling sequence; calculating a reference water level, water level fluctuation scale, water level change rate and change rate scale based on a sliding window, and calculating an urgency index; generating a target delivery probability and validity period; fixing the message payload into a basic segment and an extended segment; and adding the message to the pending queue according to the target delivery probability and validity period.

[0008] When the satellite module enters the communication state, the duration of the satellite's visible window is determined. Within the window, the link quality index sequence is obtained, and the power supply voltage and the available energy budget for the window are read. Based on the mode table, the window integral estimation is performed for each transmission mode to obtain the average single packet success probability of the window.

[0009] Based on the validity period, the basic segment messages are dequeued from the queue to form a sending block and the target delivery probability of the sending block is determined. Under the constraint of the window average single packet success probability, a check packet is generated by single check packet encoding and the minimum packet size that satisfies the target delivery probability is determined. The energy consumption is calculated and the execution mode is selected. The basic segment messages and check packets are sent in sequence.

[0010] The receiving end generates a receipt bitmap for the transmitted block and returns it to the water conservancy monitoring terminal. Based on the receipt bitmap, the confirmed messages are dequeued, and the unconfirmed messages that are still within the validity period are reserved to wait for the next satellite visibility window. The threshold offset is maintained and the threshold parameters are updated based on the receipt results.

[0011] As a preferred embodiment of the satellite communication data transmission method for water conservancy monitoring described in this invention, the steps of calculating the reference water level, water level fluctuation scale, water level change rate, and change rate scale based on a sliding window, and calculating the urgency index to generate the target delivery probability and validity period are as follows: Water level measurements are collected according to a sampling period, and a water level sliding window and a change rate sliding window are maintained. The median of the measured water level values ​​is used as the reference water level, the median of the absolute deviations between each measured water level value and the reference water level is used as the water level fluctuation scale, and the median of the absolute value of the water level change rate is used as the change rate scale. An urgency index is calculated based on the measured water level value, reference water level, water level fluctuation scale, water level change rate, and change rate scale, and the target delivery probability and validity period are simultaneously generated from the urgency index.

[0012] As a preferred embodiment of the satellite communication data transmission method for water conservancy monitoring described in this invention, the steps of adding the message to the waiting queue according to the target delivery probability and validity period are as follows: fixing the message payload into a basic segment and an extended segment; taking the current value of the unique sequence number count maintained by the water conservancy monitoring terminal as the unique sequence number of the message, and incrementing and saving the count value; writing the basic segment, extended segment, unique sequence number, target delivery probability, and validity period as waiting records into the waiting queue; prioritizing the arrangement of the waiting queue according to the validity period from shortest to longest; and when the validity periods are the same, arranging them according to the target delivery probability from highest to lowest.

[0013] As a preferred embodiment of the satellite communication data transmission method for water conservancy monitoring described in this invention, the steps of determining the satellite visibility window duration when the satellite module enters a communicable state, acquiring the link quality index sequence and reading the power supply voltage and the available energy budget within the window are as follows: determining the start and end times and window duration of the satellite visibility window through the satellite module communication state switching; acquiring the link quality index sequence and synchronously recording the power supply voltage within the window at a fixed sampling period; and determining the available energy budget at the start time of the satellite visibility window.

[0014] As a preferred embodiment of the satellite communication data transmission method for water conservancy monitoring described in this invention, the step of performing window integral estimation on each transmission mode based on the mode table to obtain the average single packet success probability of the window is as follows: for each transmission mode in the mode table, perform window integral estimation based on the link quality index sequence within the window to obtain the average single packet success probability of the window; and output the average single packet success probability of the window corresponding to each transmission mode in the order of the mode table.

[0015] As a preferred embodiment of the satellite communication data transmission method for water conservancy monitoring described in this invention, the steps of generating a check packet through single-check packet encoding and determining the minimum packet size that satisfies the target delivery probability are as follows: a transmission block is formed by dequeuing unexpired basic segments from the waiting queue according to their validity period; the target delivery probability of the transmission block is taken as the maximum target delivery probability within the transmission block; for each transmission mode, the single packet loss rate is obtained based on the average single packet success probability within the window; the packet size is incrementally increased until the packet recovery probability is not lower than the target delivery probability of the transmission block, and the minimum packet size is determined.

[0016] As a preferred embodiment of the satellite communication data transmission method for water conservancy monitoring described in this invention, the following steps are included: calculating energy consumption and selecting an execution mode, and sequentially sending basic segment messages and verification packets. This includes grouping the data according to the minimum group size, generating verification packets by XORing each byte of the basic segments within a group, calculating energy consumption based on power supply voltage, transmission current, net rate, basic segment bit length, and total number of packets, and selecting the minimum energy consumption transmission mode as the execution mode, under the conditions of recoverability probability, remaining available window time, and energy budget. After configuring the mode table, the basic segments and verification packets are sent sequentially. The receiving end deduplicates the data according to the unique sequence number and restores the missing messages when no more than one message is missing in each group and the verification packet arrives. The terminal records the transmission log and retains unsent and non-expired records.

[0017] As a preferred embodiment of the satellite communication data transmission method for water conservancy monitoring described in this invention, the steps of dequeuing confirmed messages according to the receipt bitmap and retaining unconfirmed messages that are still valid until the next satellite visibility window are as follows: the receiving end generates a receipt bitmap based on the unique sequence number of the received and restored messages; the sending block number is taken as the minimum value in the unique sequence number list of sending blocks; the sequence number bitmap in the receipt bitmap is marked bit by bit according to the range of observable unique sequence numbers starting from the sending block number, indicating whether the messages are valid or invalid and carrying a recovery flag before being transmitted back; the water conservancy monitoring terminal matches the receipt bitmap with the transmission log, dequeues confirmed records, retains unconfirmed and non-expired records for transmission, and downgrades expired records to summary records.

[0018] As a preferred embodiment of the satellite communication data transmission method for water conservancy monitoring described in this invention, the steps of maintaining the threshold offset and updating the threshold parameters based on the receipt results are as follows: taking the average single packet success probability of the execution mode within the current satellite visible window as the estimated delivery level; converting the receipt results into a determination of whether the transmission block is successful; comparing the result with the estimated delivery level to obtain the calibration direction; decreasing the threshold when successful and the estimated delivery level is low; increasing the threshold when unsuccessful and the estimated delivery level is high; normalizing the calibration intensity by probability and converting it into a threshold correction increment by the kurtosis parameter; accumulating the correction increment into the threshold offset and updating the mode table threshold parameters.

[0019] Secondly, the present invention provides a satellite communication data transmission system for water conservancy monitoring, including an urgency-driven message queuing module, which collects measured water level values ​​to form a sampling sequence, calculates reference water level, water level fluctuation scale, water level change rate and change rate scale based on a sliding window, calculates an urgency index, generates target delivery probability and validity period, fixes the message payload to a basic segment and an extended segment, and adds the message to the pending queue according to the target delivery probability and validity period.

[0020] The link evaluation and success rate estimation module determines the satellite's visible window duration when the satellite module enters the communicable state. Within the window, it acquires the link quality index sequence and reads the power supply voltage and available energy budget for the window. Based on the mode table, it performs window integral estimation for each launch mode to obtain the average single packet success probability within the window.

[0021] The single-check minimum packet and mode selection sending module prioritizes dequeuing basic segment messages from the waiting queue according to their validity period to form sending blocks and determines the target delivery probability of the sending blocks. Under the constraint of the window average single packet success probability, it generates check packets through single-check packet encoding and determines the minimum packet size that satisfies the target delivery probability. It calculates energy consumption, selects the execution mode, and sends basic segment messages and check packets in sequence.

[0022] The acknowledgment bitmap confirmation and threshold update module generates an acknowledgment bitmap for the sending block and returns it to the water conservancy monitoring terminal. Based on the acknowledgment bitmap, confirmed messages are dequeued, while unconfirmed messages that are still valid are retained and await the next satellite visibility window. The threshold offset is maintained and the threshold parameters are updated based on the acknowledgment results.

[0023] The beneficial effects of this invention are as follows: by calculating the reference water level, water level fluctuation scale, and rate of change scale through a sliding window and a rate of change sliding window, an urgency index is formed, and the target delivery probability and validity period are generated, realizing the timeliness distinction and delivery target constraint of water information messages. The average single packet success probability of the window is obtained by window integral estimation of the link quality index sequence within the satellite visible window, and the threshold parameters are updated by maintaining the threshold offset in combination with the receipt bitmap, so that the mode table mapping self-calibrates with the window, thereby improving the stability and verifiability of reliable delivery under the constraint of available energy budget. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of a satellite communication data transmission method for water conservancy monitoring.

[0026] Figure 2 This is a schematic diagram of a satellite communication data transmission system for water conservancy monitoring.

[0027] Figure 3 This is a schematic diagram of the urgency index and the classification threshold.

[0028] Figure 4 This is a flowchart for receipt bitmap confirmation and threshold update. Detailed Implementation

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0031] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0032] Reference Figures 1-4 This is one embodiment of the present invention, which provides a satellite communication data transmission method for water conservancy monitoring, including the following steps:

[0033] S1. Collect measured water level values ​​to form a sampling sequence, calculate the reference water level, water level fluctuation scale, water level change rate and change rate scale based on the sliding window, calculate the urgency index, generate the target delivery probability and validity period, fix the message payload to the basic segment and the extended segment, and add the message to the waiting queue according to the target delivery probability and validity period.

[0034] The water level is measured once by the water conservancy monitoring terminal according to the sampling period, and the measured water level value is appended to the end of the sampling sequence. The measured water level value is written into the water level sliding window. If the water level sliding window is full, the earliest measured water level value that entered the water level sliding window is removed. If the sampling sequence contains at least two samplings, the ratio of the difference between the current measured water level value and the previous measured water level value to the sampling period is used as the water level change rate of adjacent samplings. The water level change rate is written into the change rate sliding window. If the change rate sliding window is full, the earliest change rate that entered the change rate sliding window is removed.

[0035] Within the water level sliding window of the measured water level values, the median of the measured water level values ​​is taken as the reference water level, and the median of the absolute deviation between each measured water level value and the reference water level is calculated as the water level fluctuation scale.

[0036] Within the sliding window of the rate of change of water level, the median of the absolute value of the rate of change of water level is taken as the rate of change measure.

[0037] An urgency index is calculated based on measured water level, reference water level, water level fluctuation scale, water level change rate, and change rate scale. The urgency index is then used to generate the target delivery probability and validity period. The expression is as follows:

[0038] ;

[0039] ;

[0040] ;

[0041] in, Indicates the first The urgency index corresponding to the next sample. This indicates the sequence number of the current sample in the sampling sequence. Indicates the first The measured water level from the second sample. Indicates a reference water level. Indicates the scale of water level fluctuations. This represents a small positive number with dimensions consistent with the scale of water level fluctuations, preventing the denominator from being zero. Indicates the first The rate of change of water level corresponding to each sampling. Represents a scale of rate of change. This represents a small positive number that is dimensionlessly consistent with the scale of the rate of change, preventing the denominator from being zero. Indicates the first The target delivery probability corresponding to each sampling. Indicates the first The validity period corresponding to each sampling Indicates the maximum validity period.

[0042] Figure 3 This demonstrates the grading characteristics of urgency over time calculated by a water conservancy monitoring terminal based on a sliding window of measured water level values ​​and a sliding window of the rate of change. The horizontal axis represents the sampling time, and the vertical axis represents the urgency index corresponding to each sampling. Figure 3 The solid line represents the curve of the urgency index changing with sampling time. The three horizontal dashed lines represent the three-level urgency classification thresholds (the three-level urgency classification thresholds are usually offline calibrated by calculating the urgency index distribution using the sliding window of this invention based on historical water level and rise rate data of the station, and determined through playback or simulation verification in conjunction with the hydrological operational alarm level, satellite visibility window, and available energy budget carrying capacity constraints). These thresholds are used to determine the process of the water situation transitioning from normal to a higher urgency level. Figure 3 The interval marked by the red dashed box in the above figure represents the critical period when the urgency index rises rapidly and crosses the classification threshold. Figure 3 The figure below shows a magnified comparison of the intervals. After magnification, it can be clearly observed that the urgency index reaches a local maximum value at the characteristic peak and successively crosses higher-level thresholds. This indicates that the deviation of the measured water level from the reference water level increases and the water level change rate increases simultaneously, thus jointly pushing up the urgency index. Since this invention generates the target delivery probability and validity period simultaneously from the urgency index, the crossing of the peak and threshold directly triggers a higher target delivery probability and a shorter validity period, enabling water information messages to achieve timeliness differentiation and delivery target constraints. That is, messages within the urgency interval are assigned stricter delivery targets and are prioritized in the waiting queue according to the shorter validity period.

[0043] The corresponding sampled message payload is fixed into a basic segment and an extended segment. The basic segment includes the site identifier, timestamp, measured water level, alarm bit, low battery bit, and unique sequence number. The extended segment includes a trend summary or original fragment index information.

[0044] The message payload refers to the set of fields of water conservancy monitoring information reported this time.

[0045] Take the current value of the unique serial number count maintained by the water conservancy monitoring terminal as the unique serial number of the message, and increment and save the count value.

[0046] The basic segment, extended segment, unique sequence number, target delivery probability, and validity period are written as a pending record into the pending queue. The pending queue adopts a deterministic sorting rule, prioritizing the sorting by validity period from shortest to longest. When the validity periods are the same, they are sorted by target delivery probability from highest to lowest.

[0047] S2. When the satellite module enters the communication state, determine the duration of the satellite's visible window, obtain the link quality index sequence within the window, and read the power supply voltage and the available energy budget for the window. Based on the mode table, perform window integral estimation for each transmission mode to obtain the average single packet success probability of the window.

[0048] The system continuously reads the communication status of the satellite module. When the satellite module switches from a non-communicable state to a communicable state, the current time is recorded as the start time of the satellite's visible window. The system continues to read the communication status of the satellite module. When the satellite module switches from a communicable state to a non-communicable state, the current time is recorded as the end time of the satellite's visible window.

[0049] The time difference between the end time and the start time is used as the duration of the satellite visibility window, and the start and end times of the satellite visibility window and the duration of the satellite visibility window are recorded as the basic parameters of this satellite visibility window.

[0050] After the satellite visibility window is opened, the sampling action is repeated once within the satellite visibility window according to the sampling period. At each sampling time, the link quality index is read from the satellite module and recorded, so that the readings form a link quality index sequence in chronological order.

[0051] Link quality index refers to the measurable value that a satellite module can provide for the current wireless or satellite link when it is in a communicable state. It is used to estimate the probability that a single message can be successfully delivered within the current satellite visibility window.

[0052] At the same sampling moment each time the link quality index is read, the power supply voltage is read and recorded synchronously to align the power supply voltage with the link quality index sequence time.

[0053] At the start of the satellite visibility window, the available energy budget for the current satellite visibility window is determined based on the current power supply conditions, and an update record of the remaining available energy budget is maintained within the satellite visibility window.

[0054] The available energy budget for a given window refers to the maximum energy limit that a water conservancy monitoring terminal is allowed to allocate to satellite communication transmission-related actions within the current satellite visibility window.

[0055] Read the mode table. Each transmission mode in the mode table contains the transmission power level, modulation and coding level, net rate, transmission current, threshold parameter, and kurtosis parameter. The mode table is used as the sole mapping basis for the link quality indicator sequence to the success probability of a single packet.

[0056] Transmit power level refers to the discrete transmit power settings supported by the satellite module.

[0057] Modulation coding profile refers to the combination profile of modulation methods and error correction coding strength supported by the satellite module.

[0058] Net rate refers to the effective bit rate available for payload transmission in the current transmit mode.

[0059] Transmit current refers to the average current during transmission in a given transmission mode.

[0060] Threshold parameters refer to the reference thresholds for link quality indicators that are consistent with the dimensions of link quality indicators.

[0061] The kurtosis parameter refers to the speed of transition from low success to high success in a logic mapping, which makes the mapping curve adaptable to the sensitivity of different emission modes.

[0062] For each launch mode in the mode table, window integral estimation is performed using the link quality index sequence within the satellite's visible window to obtain the window-average single-packet success probability corresponding to the launch mode. The expression is as follows:

[0063] ;

[0064] in, Indicates the first The average success probability of a single packet within the window corresponding to each transmission mode. This indicates the index of the launch mode in the mode table. Indicates the duration of the satellite visibility window. Indicates the start time of the satellite visibility window. Indicates the end time of the satellite visibility window. Indicates the first Steepness parameters for each emission mode, Indicates time Link quality metrics, Indicates the first Threshold parameters for each transmission mode.

[0065] The average single packet success probability corresponding to each launch mode is output in the order of the mode table, and recorded together with the start and end times of the satellite visible window, the duration of the satellite visible window, the link quality index sequence, the power supply voltage record, and the available energy budget of the window as the evaluation result of the current satellite visible window.

[0066] S3. Dequeue basic segment messages from the waiting queue according to their validity period to form a sending block and determine the target delivery probability of the sending block. Under the constraint of the window average single packet success probability, generate a check packet through single check packet encoding and determine the minimum packet size that satisfies the target delivery probability. Calculate the energy consumption and select the execution mode, and send the basic segment messages and check packets in sequence.

[0067] Starting from the head of the queue, each pending record is checked sequentially. If the validity period of a pending record has expired, it is removed from the queue and does not participate in the current satellite visibility window. If the validity period has not expired, the basic segment of the pending record is taken out and added to the transmission block, and the unique sequence number of the pending record is added to the sequence number list of the transmission block. This process is repeated until the remaining available time of the window is insufficient to complete the subsequent transmission action, the available energy budget of the window is insufficient to support the subsequent transmission action, or there are no pending records in the queue. If any of these conditions are met, the process of adding records stops.

[0068] The target delivery probability corresponding to the sending block is determined as the maximum value among the target delivery probabilities of all basic segment messages within the sending block.

[0069] For each transmission mode in the mode table, first read the average single-packet success probability corresponding to the transmission mode, and obtain the single-packet loss rate based on the average single-packet success probability. Start by increasing the packet size from the minimum feasible packet size and try different packet sizes. When the packet recovery probability under the current packet size is not lower than the delivery probability of the sent block target, the current packet size is determined as the minimum packet size for the transmission mode. The expression for the packet recovery probability is:

[0070] ;

[0071] ;

[0072] in, Indicates the first The probability of loss of a single transmitted packet under each transmission mode. Indicates the first There are several transmission modes and the group size is [number]. At that time, the probability that a basic segment message within a packet can be completely recovered under a single checksum mechanism. This indicates the packet size, which is the number of basic segment messages in a packet.

[0073] After determining the minimum packet size corresponding to the transmission mode, the packets are grouped according to the order of the basic segment messages within the transmission block. A check packet is generated for each full packet. The contents of all basic segment messages in the same byte position within the packet are XORed byte by byte to obtain the contents of the corresponding byte position of the check packet, so that the length of the check packet is consistent with the length of the basic segment message.

[0074] For each transmission mode, energy consumption is calculated based on the supply voltage, transmission current, net rate, basic segment bit length, and total number of packets transmitted in the transmission block (determined by the number of basic segment messages within the transmission block and the number of check packets generated after dividing the block according to the minimum packet size of the transmission mode). Then, the transmission mode with the lowest energy consumption is selected, provided that the remaining available window duration and the available energy budget are met. The energy consumption expression is as follows:

[0075] ;

[0076] in, Indicates the use of the first The energy consumed by each transmission mode to complete the transmission of a block. Indicates the supply voltage. Indicates the first Average current during transmission in each transmission mode. Indicates the first The total number of packets that a transmission block needs to send under each transmission mode and the minimum packet size of that mode. This indicates the bit length of a single basic segment message after it has been encoded by the satellite module's transmission interface. Indicates the first Net rate of each emission mode.

[0077] The minimum packet size for the launch mode ensures that the packet recovery probability is not less than the target delivery probability of the transmitted block, the transmission duration calculated according to the launch mode does not exceed the remaining available time of the window, and the energy consumption calculated according to the launch mode does not exceed the available energy budget of the window. Among all launch modes that simultaneously meet the conditions, the one with the lowest energy consumption is selected as the execution mode for the current satellite visibility window. If the energy consumption is the same, the launch mode that appears earlier in the mode table is selected.

[0078] Transmission duration refers to the ratio of the total number of bits transmitted to the net rate in execution mode. The total number of bits transmitted is determined by the total number of packets transmitted in the transmission block and the bit length of the base segment.

[0079] Write the transmit power level and modulation code level corresponding to the execution mode into the satellite module, so that the satellite module can perform transmission with the transmit power level and modulation code level corresponding to the execution mode. At the same time, use the net rate and transmit current of the execution mode as the basis for calculating the transmission resources of the current satellite visible window.

[0080] The basic segment messages are sent sequentially according to their original order within the transmission block, and a corresponding check packet is sent at the end of each packet. During the transmission process, the remaining available time of the window is updated according to the number of packets sent and the basic segment bit length, and the remaining amount of the available energy budget of the window is updated according to the energy consumption. When the remaining available time of the window or the available energy budget of the window is insufficient to continue sending the next packet, the transmission is stopped and the unsent records are left in the waiting queue to wait for the next satellite visible window.

[0081] The receiving end deduplicates each received basic segment message according to its unique sequence number and stores it in the database. It also groups and aggregates the received basic segment messages and check packets within the same group.

[0082] When the number of missing basic segment messages within a group is within the recoverable range of the check packet, the receiving end recovers the missing messages by generating the check packet using the byte XOR relationship of the basic segment messages within the group and stores them in the database. When the number of missing messages exceeds the recoverable range, the receiving end only stores the received messages and records the unique sequence number of the missing messages.

[0083] The recoverable range of missing segments in a check packet refers to the fact that the number of missing basic segment messages in each packet does not exceed one, and the check packet corresponding to the missing message has been received by the receiving end.

[0084] The water conservancy monitoring terminal generates a transmission log, which includes a unique sequence number list of basic segment messages that have been transmitted, the execution mode, the minimum group size of the execution mode, the group boundary corresponding to the check packet, and the actual transmission time and energy consumption within the current satellite visibility window. Unsent but still valid records are kept in the pending transmission queue.

[0085] S4. The receiving end generates a receipt bitmap for the sending block and returns it to the water conservancy monitoring terminal. According to the receipt bitmap, the confirmed messages are dequeued, and the unconfirmed messages that are still within the validity period are reserved to wait for the next satellite visibility window. The threshold offset is maintained and the threshold parameters are updated based on the receipt results.

[0086] The receiving end summarizes the received or recovered basic segment messages into a unique sequence number set based on their unique sequence numbers. The receiving end generates a receipt bitmap based on the range of observable unique sequence numbers within the sending block. The receipt bitmap includes the sending block number, the received or recovered sequence number bitmap, and a recovery flag. The sequence number bitmap is marked bit by bit in the order of the unique sequence number list. If the basic segment message corresponding to the unique sequence number has been received or recovered and entered into the database, it is marked as valid; otherwise, it is marked as invalid. The recovery flag is used to indicate whether the sending block has undergone a byte-based XOR recovery process. The receiving end returns the receipt bitmap to the water conservancy monitoring terminal via satellite link, enabling the water conservancy monitoring terminal to match the receipt results with the sending log.

[0087] The send block number is taken as the smallest unique sequence number in the send block unique sequence number list in the send log.

[0088] When generating the sequence number bitmap, the receiving end uses the sending block number as the starting sequence number of the sequence number bitmap, and uses the difference between the largest unique sequence number observed by the receiving end in the sending block and the sending block number plus one as the length of the sequence number bitmap. Within the length coverage area, the corresponding position of the unique sequence number that is not observed but falls within the range is marked as invalid, so that each bit in the sequence number bitmap corresponds to the position of the difference between the unique sequence number and the sending block number. When matching, the water conservancy monitoring terminal uses the unique sequence number list of the sending block in the sending log as the standard, and the unique sequence number that falls outside the coverage area of ​​the sequence number bitmap is regarded as unconfirmed.

[0089] After receiving the acknowledgment bitmap, the water conservancy monitoring terminal locates the corresponding transmission log according to the transmission block number and parses it to obtain the set of confirmed unique sequence numbers. For the pending records corresponding to the confirmed unique sequence numbers, they are dequeued and will no longer participate in subsequent satellite visible window transmissions. For pending records with unconfirmed unique sequence numbers, if they are still within the validity period, they remain in the pending queue and maintain the established sorting rules, waiting for the next satellite visible window to continue transmission. If they have expired, they are discarded or downgraded to summary records. Summary records only retain the station identifier, timestamp, measured water level value, alarm bit, low battery bit, unique sequence number, and the target delivery probability and validity period corresponding to the pending record. After processing, the updated pending queue is obtained.

[0090] The water conservancy monitoring terminal updates the threshold parameters corresponding to the execution mode based on the receipt results, while the threshold parameters for the remaining transmission modes remain unchanged. The receipt results for the transmission block are converted into a success or failure determination. If all unique sequence numbers of the transmission block in the transmission log are marked as valid in the receipt bitmap, it is considered successful; otherwise, it is considered a failure. The average single-packet success probability within the current satellite visibility window of the execution mode is taken as the estimated delivery level. The estimated delivery level is compared with the success or failure determination of the transmission block to obtain the calibration direction. When the determination is successful and the estimated delivery level is low, the threshold parameters are corrected in the direction of decreasing the threshold parameters. The correction strength depends on the relative value of the estimated delivery level. The degree of inadequacy of the actual delivery status reflected by the proportion of the success determination probability is scaled by a normalized term consisting of the estimated delivery level and the complementary probability of the estimated delivery level. The normalized term is then adjusted by a kurtosis parameter to obtain a threshold correction increment consistent with the dimensions of the link quality index. When the determination is failure and the estimated delivery level is high, the threshold parameter is corrected in the direction of increasing the threshold parameter. The correction strength depends on how high the estimated delivery level is relative to the actual delivery status reflected by the failure determination. The threshold correction increment is calculated by normalization and kurtosis parameter. When the determination is success and the estimated delivery level is not low, or when the determination is failure and the estimated delivery level is not high, the threshold parameter is not updated.

[0091] The threshold correction increment is accumulated into the threshold offset of the execution mode, and the threshold parameters in the mode table are updated with the updated threshold offset. The updated threshold parameters are then directly used when performing window integration estimation in the next satellite visible window. The window average single packet success probability of the next satellite visible window is updated, and the selection of the execution mode with the minimum packet size and the minimum energy consumption is still constrained.

[0092] Threshold offset refers to the cumulative correction amount of the threshold parameters maintained by the water conservancy monitoring terminal for the execution mode, which is used to obtain the updated threshold parameters based on the original threshold parameters.

[0093] This embodiment also provides a satellite communication data transmission system for water conservancy monitoring, including:

[0094] The urgency-driven message queuing module collects measured water level values ​​to form a sampling sequence, calculates the reference water level, water level fluctuation scale, water level change rate and change rate scale based on a sliding window, calculates the urgency index, generates the target delivery probability and validity period, fixes the message payload to the basic segment and the extended segment, and adds the message to the waiting queue according to the target delivery probability and validity period.

[0095] The link evaluation and success rate estimation module determines the satellite's visible window duration when the satellite module enters the communicable state. Within the window, it acquires the link quality index sequence and reads the power supply voltage and the available energy budget for the window. Based on the mode table, it performs window integral estimation for each launch mode to obtain the average single packet success probability of the window.

[0096] The single-check minimum packet and mode selection sending module first dequeues basic segment messages from the queue to be sent according to the validity period to form a sending block and determines the target delivery probability of the sending block. Under the constraint of the window average single packet success probability, it generates a check packet through single-check packet encoding and determines the minimum packet size that satisfies the target delivery probability. It calculates energy consumption, selects the execution mode, and sends basic segment messages and check packets in sequence.

[0097] The acknowledgment bitmap confirmation and threshold update module generates an acknowledgment bitmap for the sending block and returns it to the water conservancy monitoring terminal. Based on the acknowledgment bitmap, confirmed messages are dequeued, while unconfirmed messages that are still valid are retained and await the next satellite visibility window. The threshold offset is maintained and the threshold parameters are updated based on the acknowledgment results.

[0098] In summary, this invention calculates the reference water level, water level fluctuation scale, and rate of change scale using a sliding window and a rate of change sliding window to form an urgency index, generating the target delivery probability and validity period. This enables the timeliness differentiation and delivery target constraint of hydrological information messages. The average single-packet success probability of the window is obtained by window integral estimation of the link quality index sequence within the satellite visible window. Furthermore, the threshold parameters are updated by maintaining the threshold offset using the receipt bitmap, allowing the mode table mapping to self-calibrate with the window. This improves the stability and verifiability of reliable delivery under the constraint of available energy budget.

[0099] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A satellite communication data transmission method for water conservancy monitoring, characterized in that: include, The system collects measured water level values ​​to form a sampling sequence, calculates the reference water level, water level fluctuation scale, water level change rate and change rate scale based on a sliding window, calculates the urgency index, generates the target delivery probability and validity period, fixes the message payload in the basic segment and extended segment, and adds the message to the pending queue according to the target delivery probability and validity period. When the satellite module enters the communication state, the duration of the satellite's visible window is determined. Within the window, the link quality index sequence is obtained, and the power supply voltage and the available energy budget for the window are read. Based on the mode table, the window integral estimation is performed for each transmission mode to obtain the average single packet success probability of the window. Based on the validity period, the basic segment messages are dequeued from the queue to form a sending block and the target delivery probability of the sending block is determined. Under the constraint of the window average single packet success probability, a check packet is generated by single check packet encoding and the minimum packet size that satisfies the target delivery probability is determined. The energy consumption is calculated and the execution mode is selected. The basic segment messages and check packets are sent in sequence. The receiving end generates a receipt bitmap for the transmitted block and returns it to the water conservancy monitoring terminal. Based on the receipt bitmap, the confirmed messages are dequeued, and the unconfirmed messages that are still within the validity period are reserved to wait for the next satellite visibility window. The threshold offset is maintained and the threshold parameters are updated based on the receipt results.

2. The satellite communication data transmission method for water conservancy monitoring as described in claim 1, characterized in that: The specific steps for calculating the reference water level, water level fluctuation scale, water level change rate, and change rate scale based on a sliding window, and calculating the urgency index to generate the target delivery probability and validity period are as follows: The measured water level values ​​are collected according to the sampling period, and the water level sliding window and the rate of change sliding window are maintained. The median of the measured water level values ​​is used as the reference water level, the median of the absolute deviation between each measured water level value and the reference water level is used as the water level fluctuation scale, and the median of the absolute value of the rate of change of water level is used as the rate of change scale. The urgency index is calculated based on the measured water level, reference water level, water level fluctuation scale, water level change rate, and change rate scale. The urgency index is then used to generate the target delivery probability and validity period.

3. The satellite communication data transmission method for water conservancy monitoring as described in claim 2, characterized in that: The specific steps for adding messages to the pending queue based on target delivery probability and validity period are as follows: The message payload is fixed in the basic segment and the extended segment. The current value of the unique sequence number count maintained by the water conservancy monitoring terminal is taken as the unique sequence number of the message, and the count value is incremented and saved. Write the base segment and extended segment, unique sequence number, target delivery probability, and validity period as pending records into the pending queue. The pending queue is first arranged in order of validity period from shortest to longest. When the validity periods are the same, they are arranged in order of target delivery probability from highest to lowest.

4. The satellite communication data transmission method for water conservancy monitoring as described in claim 3, characterized in that: When the satellite module enters a communicable state, the duration of the satellite's visible window is determined. Within the window, the link quality index sequence is obtained, and the power supply voltage and available energy budget for the window are read. The specific steps are as follows: The start and end times and duration of the satellite visibility window are determined by switching the communication status of the satellite module. Within the window, the link quality index sequence is collected at a fixed sampling period and the power supply voltage is recorded synchronously. Determine the available energy budget for the window at the start of the satellite visibility window.

5. The satellite communication data transmission method for water conservancy monitoring as described in claim 4, characterized in that: The step of performing window integration estimation on each transmission mode based on the mode table to obtain the average single-packet success probability within the window is as follows: For each transmission mode in the mode table, window integral estimation is performed based on the link quality index sequence within the window to obtain the average single packet success probability within the window. The average single packet success probability for each launch mode is output in the order of the mode table.

6. The satellite communication data transmission method for water conservancy monitoring as described in claim 5, characterized in that: The specific steps for generating a check packet through single-check block encoding and determining the minimum packet size that satisfies the target delivery probability are as follows: A sending block is formed by dequeuing unexpired basic segments from the waiting queue according to their validity period. The target delivery probability of the sending block is the highest target delivery probability in the sending block. For each transmission mode, the packet loss rate is obtained based on the average single packet success probability within the window. The packet size is then increased until the packet recovery probability is not lower than the target delivery probability of the transmitted block, and the minimum packet size is determined.

7. The satellite communication data transmission method for water conservancy monitoring as described in claim 6, characterized in that: The calculation of energy consumption and selection of execution mode, followed by the sequential transmission of base segment messages and check packets, includes: Grouping is performed according to the minimum group size, and a check packet is generated by XORing the basic segment within the group byte by byte. Under the conditions of recoverability probability, remaining available window time and energy budget, energy consumption is calculated based on supply voltage, transmission current, net rate, basic segment bit length and total number of packets, and the minimum energy consumption transmission mode is selected as the execution mode. After configuring the mode table, the basic segment and the verification packet are sent in sequence. The receiving end deduplicates the data according to the unique sequence number and restores the missing message when no more than one message is missing in each group and the verification packet arrives. The terminal records the sending log and retains the unsent and non-expired records.

8. The satellite communication data transmission method for water conservancy monitoring as described in claim 7, characterized in that: The steps for dequeuing confirmed messages according to the receipt bitmap and retaining unconfirmed messages that are still valid until the next satellite visibility window are as follows: The receiving end generates a receipt bitmap based on the unique sequence number of the received and restored data. The sending block number is taken as the minimum value in the unique sequence number list of the sending block. The sequence number bitmap in the receipt bitmap is marked bit by bit as valid and invalid according to the observable unique sequence number range starting from the sending block number and then sent back with a recovery flag. The water conservancy monitoring terminal matches the receipt bitmap with the sending log, removes confirmed records from the queue, retains unconfirmed and non-expired records for later sending, and downgrades expired records to summary records.

9. The satellite communication data transmission method for water conservancy monitoring as described in claim 8, characterized in that: The specific steps for maintaining the threshold offset and updating the threshold parameters based on the receipt results are as follows: The average single-packet success probability within the current satellite visibility window of the execution mode is taken as the estimated delivery level. The receipt result is converted into a judgment of whether the transmission block was successful and compared with the estimated delivery level to obtain the calibration direction. When successful and the estimated delivery level is low, the threshold is reduced. When unsuccessful and the estimated delivery level is high, the threshold is increased. The calibration intensity is normalized by probability and converted into a threshold correction increment by the steepness parameter. The correction increment is accumulated as the threshold offset and the mode table threshold parameter is updated.

10. A satellite communication data transmission system for water conservancy monitoring, based on the satellite communication data transmission method for water conservancy monitoring according to any one of claims 1 to 9, characterized in that: include, The urgency-driven message queuing module collects measured water level values ​​to form a sampling sequence, calculates the reference water level, water level fluctuation scale, water level change rate and change rate scale based on a sliding window, calculates the urgency index, generates the target delivery probability and validity period, fixes the message payload to the basic segment and the extended segment, and adds the message to the waiting queue according to the target delivery probability and validity period. The link evaluation and success rate estimation module determines the satellite's visible window duration when the satellite module enters the communicable state. Within the window, it acquires the link quality index sequence and reads the power supply voltage and the available energy budget for the window. Based on the mode table, it performs window integral estimation for each launch mode to obtain the average single packet success probability of the window. The single-check minimum packet and mode selection sending module first dequeues basic segment messages from the queue to be sent according to the validity period to form a sending block and determines the target delivery probability of the sending block. Under the constraint of the window average single packet success probability, it generates a check packet through single-check packet encoding and determines the minimum packet size that satisfies the target delivery probability. It calculates energy consumption, selects the execution mode, and sends basic segment messages and check packets in sequence. The acknowledgment bitmap confirmation and threshold update module generates an acknowledgment bitmap for the sending block and returns it to the water conservancy monitoring terminal. Based on the acknowledgment bitmap, confirmed messages are dequeued, while unconfirmed messages that are still valid are retained and await the next satellite visibility window. The threshold offset is maintained and the threshold parameters are updated based on the acknowledgment results.

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