A ranging communication integrated implementation method and system

Abstract

The application provides a ranging and communication integrated implementation method and system, and relates to the technical field of ranging and communication integration. The method comprises the following steps: performing non-uniform coding on a communication information bit stream to generate a non-uniform communication code sequence; fusing the non-uniform communication code sequence with a preset ranging pseudo code sequence to obtain an integrated composite code sequence; performing phase modulation on a carrier based on the integrated composite code sequence to output a modulated wave signal; demodulating the modulated wave signal to obtain a baseband composite code sequence estimation; performing pseudo code synchronization on the baseband composite code sequence estimation to obtain a measured distance, and performing non-uniform decoding on the baseband composite code sequence estimation to recover the communication information. The application has the advantages of high communication rate, simultaneous ranging and communication, and no influence on the main interference phase signal measurement.

Description

Technical Field

[0001] This invention relates to the technical field of integrated ranging and communication, and in particular to a method and system for implementing integrated ranging and communication. Background Technology

[0002] With the development of technologies such as satellite navigation, mobile communication, and IoT positioning, the importance of integrated ranging and communication technology is becoming increasingly prominent. In particular, the development of space science missions has put forward multi-faceted requirements for inter-satellite ranging and communication integrated technology.

[0003] Existing integrated ranging and communication technologies mainly include the following technical approaches, but all have certain shortcomings: The first approach is based on direct sequence spread spectrum, which achieves integrated functionality by combining communication codes and ranging pseudo-codes. Its ranging performance and communication rate are strongly coupled. To achieve reliable ranging, traditional design principles require the communication code rate to be significantly lower than the pseudo-code rate. However, in applications with large variations in inter-satellite distances, the pseudo-code rate is limited by its dynamic range and cannot be further improved, thus restricting the communication rate. The second approach is based on time division multiplexing, which achieves rate decoupling in principle by alternately transmitting ranging and communication signals. However, the interruption of the ranging signal during the communication time slot disrupts the continuity of carrier and pseudocode tracking, easily introducing reacquisition problems in high-dynamic, long-delay links and increasing system uncertainty. The third approach, based on higher-order modulation or multi-carrier multiplexing, improves communication rate by increasing spectrum utilization efficiency, but often requires compromises in signal envelope, phase continuity, and peak-to-average power ratio (PAPR), potentially introducing significant modulation sidebands and spectral leakage. Furthermore, the PAPR characteristics of multi-carrier signals impose stringent requirements on the linearity of onboard power amplifiers, making it unsuitable for use in space science missions where the main interferometric phase signal is the primary measurement tool. Therefore, existing integrated ranging and communication technologies suffer from low communication rates, the inability to perform ranging and communication simultaneously, and interference with the measurement of the main interferometric phase signal. Summary of the Invention

[0004] Therefore, it is necessary to provide a method and system for integrating ranging and communication to address the problems of existing ranging and communication integration technologies, which has the advantages of high communication rate, simultaneous ranging and communication, and no impact on the measurement of the main interferometric phase signal.

[0005] To achieve the above-mentioned technical effects, the technical solution of the present invention is as follows: A method for integrating ranging and communication includes: S1. Perform unbalanced encoding on the communication information bit stream to generate an unbalanced communication code sequence; S2. The unbalanced communication code sequence is fused with a preset ranging pseudocode sequence to obtain an integrated composite code sequence; S3. Based on the integrated composite code sequence, the carrier wave is phase-modulated to output a modulated wave signal; S4. Demodulate the modulated wave signal to obtain a baseband composite code sequence estimate; S5. Perform pseudocode synchronization on the baseband composite code sequence estimation to obtain the measured distance, and perform unbalanced decoding on the baseband composite code sequence estimation to recover the communication information.

[0006] Preferably, the communication information bitstream is unbalancedly encoded according to a preset unbalanced encoding rule to generate an unbalanced communication code sequence, wherein the unbalanced encoding rule is as follows: In the communication information bit stream, every m information bits are mapped to an encoding unit of length n. In the encoding unit, there are exactly w symbols that are second logic values, and the remaining (nw) symbols are first logic values. Here, n and w are positive integers, and satisfy n = w*(k+1), m ≤ log2(C(n, w)), k>0, and C is a combinatorial function. The encoding unit is denoted as the unbalanced communication code sequence.

[0007] Preferably, the ratio of the number of symbols in the first logic value to the number of symbols in the second logic value is a preset fixed value p, and p > 1.

[0008] Preferably, the step of fusing the unbalanced communication code sequence with a preset ranging pseudocode sequence to obtain an integrated composite code sequence includes: performing a sample-by-sample XOR operation on the unbalanced communication code sequence and the preset ranging pseudocode sequence to obtain the integrated composite code sequence.

[0009] Preferably, the step of performing phase modulation on the carrier based on the integrated composite code sequence and outputting a modulated wave signal includes: when the integrated composite code sequence is a first logic value, applying a first preset phase offset to the carrier and outputting a modulated wave signal after the first preset phase offset; when the integrated composite code sequence is a second logic value, applying a second preset phase offset to the carrier and outputting a modulated wave signal after the second preset phase offset.

[0010] Preferably, the demodulation of the modulated wave signal to obtain the baseband composite code sequence estimate includes: S41. Interfere the modulated wave signal with a preset local oscillator signal to obtain an interference wave signal; S42. The interference wave signal is converted into an electrical signal by a detector, and then the electrical signal is amplified and converted from analog to digital to obtain a digital signal; S43. Perform digital down-conversion and carrier phase tracking on the digital signal to obtain a baseband signal; S44. Perform symbol timing synchronization and decision-making on the baseband signal to obtain the baseband composite code sequence estimate.

[0011] Preferably, the step of obtaining the measured distance by pseudocode synchronization of the baseband composite code sequence estimation includes: S51. Perform cross-correlation calculation between the baseband composite code sequence estimate and the local ranging pseudocode sequence to obtain the correlation value; S52. When the correlation value exceeds a preset threshold, a delay-locked loop is used to generate a leading pseudocode copy and a lagging pseudocode copy, and cross-correlation operations are performed with the baseband composite code sequence estimate to obtain the leading correlation function and the lagging correlation function. S53. An error signal is generated from the difference between the leading correlation function and the lagging correlation function. The generated phase of the local ranging pseudocode sequence is aligned with the received pseudocode sequence based on the feedback control of the error signal. The original phase difference between the local ranging pseudocode sequence and the received pseudocode sequence is output. S54. Calculate the measured distance using the original phase difference.

[0012] Preferably, the step of performing unbalanced decoding to recover communication information from the baseband composite code sequence estimation includes: S55. Perform a sample-by-sample XOR operation on the local ranging pseudocode sequence synchronized with the baseband composite code sequence estimate to obtain the unbalanced communication code sequence estimate. S56. Perform inverse mapping on the estimated unbalanced communication code sequence to obtain the bit stream of communication information.

[0013] Preferably, the step of inversely mapping the estimated unbalanced communication code sequence to obtain the communication information bitstream includes: S561. Divide the unbalanced communication code sequence estimate into multiple code segments according to n information bits; S562. Detect a unique pair of consecutive second logic value segments in each code segment and determine the starting position index of the second logic value segments; S563. Based on the starting position index, determine the corresponding m information bits according to the preset mapping relationship; S564. Concatenate the m information bits corresponding to each code segment in sequence to obtain the bit stream of the communication information.

[0014] The present invention also provides an integrated ranging and communication system, comprising: The unbalanced encoding module is used to perform unbalanced encoding on the communication information bit stream to generate an unbalanced communication code sequence. A composite code generation module is used to fuse the unbalanced communication code sequence with a preset ranging pseudocode sequence to obtain an integrated composite code sequence. The phase modulation module is used to perform phase modulation on the carrier wave based on the integrated composite code sequence and output a modulated wave signal; The signal demodulation module is used to demodulate the modulated wave signal to obtain a baseband composite code sequence estimate; The composite code processing module is used to perform pseudocode synchronization on the baseband composite code sequence estimation to obtain the measured distance, and to perform unbalanced decoding on the baseband composite code sequence estimation to recover the communication information.

[0015] Compared with the prior art, the beneficial effects of the technical solution of the present invention are: This invention proposes an integrated ranging and communication method and system. First, the communication information bitstream is unbalancedly encoded to generate an unbalanced communication code sequence. This encoding method has the advantages of small low-frequency components and applicability to low-depth phase modulation, thus not affecting the measurement of the main interference phase signal. Then, the unbalanced communication code sequence is fused with a preset ranging pseudo-code sequence to obtain an integrated composite code sequence, thereby improving the communication rate and enabling simultaneous transmission of ranging and communication information. Next, the carrier wave is phase-modulated based on the integrated composite code sequence to output a modulated wave signal. Then, the modulated wave signal is demodulated to obtain a baseband composite code sequence estimate. Finally, pseudo-code synchronization of the baseband composite code sequence estimate yields the measured distance, and unbalanced decoding of the baseband composite code sequence estimate recovers the communication information, thus realizing integrated ranging and communication. Attached Figure Description

[0016] Figure 1 This is a flowchart of the integrated ranging and communication implementation method in an embodiment of the present invention; Figure 2 This is a schematic diagram of the integrated inter-satellite laser pseudocode ranging and communication system in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of conventional encoding in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the new code in an embodiment of the present invention; Figure 5 This is an overall schematic diagram of the correlation function between the transmitting end composite code and the receiving end pseudocode in the new encoding scheme of this invention embodiment; Figure 6 This is a central detail diagram of the correlation function between the transmitting end composite code and the receiving end pseudocode in the new coding scheme of this invention embodiment; Figure 7 This is a schematic diagram showing the central detail of the error signal between the transmitting end composite code and the receiving end pseudo code in the new coding scheme of this invention embodiment; Figure 8 This is the power amplitude spectrum of the new encoding scheme in an embodiment of the present invention; Figure 9 This is a structural block diagram of the inter-satellite laser pseudocode ranging and communication integrated system in an embodiment of the present invention. Detailed Implementation

[0017] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. It is understandable to those skilled in the art that some well-known details may be omitted from the accompanying drawings; To facilitate understanding of this embodiment, the prior art information of this embodiment is first introduced as follows: With the development of technologies such as satellite navigation, mobile communication, and IoT positioning, the importance of integrated ranging and communication technology is becoming increasingly prominent. In particular, the development of space science missions has placed multifaceted demands on this technology. For example, in space gravitational wave detection missions, sub-meter-level inter-satellite absolute distance measurements are required on baselines ranging from tens of thousands to millions of kilometers to suppress the effects of unequal arm lengths, while simultaneously enabling inter-satellite data communication to support inter-satellite coordinated control. At the same time, to avoid interference with the main interferometric phase measurement used for gravitational wave detection, the modulation signal used for integrated inter-satellite ranging and communication also needs to meet requirements such as weak modulation and the absence of low-frequency components.

[0018] To achieve the integration of ranging and communication, typical existing technologies are mainly based on the following technical routes.

[0019] The first approach is the classic direct sequence spread spectrum scheme, which is closest to this invention. It generates a composite code by XORing the communication data bits with a high-speed ranging pseudocode. The receiver uses a local copy of the pseudocode for correlation operations to achieve pseudocode synchronization and delay measurement (ranging), while simultaneously demodulating the communication information. This scheme inherits the anti-interference and anti-multipath characteristics of traditional spread spectrum communication, has high technological maturity, and is widely used in global satellite navigation systems. However, its limitation lies in the strong coupling between ranging performance and communication rate. The mixing of the communication code and the pseudocode reduces the correlation performance of the pseudocode, and the larger the ratio of the communication code rate to the pseudocode rate, the more significant the impact. Therefore, to achieve reliable ranging, traditional design principles require the communication code rate to be significantly lower than the pseudocode rate. This limitation is even more pronounced in space applications where inter-satellite distances change rapidly, because the pseudocode rate cannot be arbitrarily increased; it is constrained by the rate of change of inter-satellite distances. An excessively high code rate leads to insufficient dynamic range, making locking difficult. Therefore, with the pseudocode rate limited by dynamic range and unable to be significantly increased, the potential for increasing the communication code rate is also locked.

[0020] The second approach is based on time-division multiplexing, employing a strategy of alternating transmission of ranging and communication signals. High-power, high-code-rate pure ranging pseudo-code is transmitted in specific time slots to ensure ranging accuracy, while high-data-rate transmission is achieved in other time slots. This method, in principle, decouples ranging and communication rates, providing flexibility for increasing communication rates. However, its essence is to simplify the integration problem into a timing switch between two independent systems, resulting in the inability to simultaneously perform ranging and communication functions. During communication transmission, the ranging signal is completely interrupted, disrupting the continuity of the carrier and pseudo-code tracking loops. In highly dynamic, long-delay inter-satellite links, this interruption forces the receiver to frequently reacquire, significantly increasing system uncertainty and even causing the ranging link to lose lock.

[0021] The third approach is based on advanced schemes using high-order modulation or multi-carrier multiplexing, aiming to achieve higher-dimensional resource utilization through innovations in signal design. For example, using Quadrature Phase Shift Keying (QPSK) modulation can transmit multiple bits of information within a single symbol period, thereby increasing communication speed at the same pseudocode rate. Furthermore, Orthogonal Frequency Division Multiplexing (OFDM) technology can transmit data in parallel on multiple orthogonal subcarriers, significantly improving spectral efficiency. However, these schemes often require compromises in signal envelope, phase continuity, and peak-to-average power ratio (PAPR), potentially introducing significant modulation sidebands and spectral leakage. For some space science missions, such as space gravitational wave detection, where the main interferometric signal carries the core scientific task of gravitational displacement measurement and requires picometer-level phase measurement accuracy, only a small portion of the modulation sidebands can be allocated for ranging and communication, making this approach unsuitable. Moreover, the PAPR characteristics of multi-carrier signals place stringent requirements on the linearity of onboard power amplifiers, making implementation difficult within limited onboard power budgets.

[0022] In summary, existing integrated ranging and communication technologies have the following main shortcomings: 1. Traditional integrated ranging and communication solutions combine the ranging pseudocode and communication code using an XOR operation. The code rate of the communication code must be lower than that of the pseudocode, and the closer the two are, the worse the ranging performance of the pseudocode. However, for space applications, inter-satellite distances vary, and to ensure dynamic range, the code rate of the pseudocode cannot be arbitrarily increased. Ultimately, this makes it difficult to improve communication speed.

[0023] 2. For a time-division multiplexing scheme for ranging and communication signals, the communication rate is not limited by the pseudocode rate. However, the ranging signal will be interrupted during communication in this scheme, which is detrimental to the tracking and locking of the ranging system.

[0024] 3. Higher-order modulation schemes can further increase communication rates by transmitting multiple bits per symbol. However, for some space science missions, such as space gravitational wave detection, the main interferometric signal carries the primary scientific task, which contradicts this modulation scheme. Similar problems exist with techniques such as multi-carrier multiplexing.

[0025] Therefore, it is necessary to provide a new integrated ranging and communication system, introducing an integrated ranging and communication technology based on a new coding scheme, so as to achieve a communication code rate that exceeds the ranging pseudocode rate, while maintaining the ranging capability based on the autocorrelation characteristics of the pseudocode, and avoiding affecting the measurement of the main interferometric signal that undertakes the core scientific task, so as to overcome the shortcomings of the above-mentioned existing technologies.

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0027] Example 1 like Figure 1 As shown, this embodiment provides an integrated ranging and communication implementation method, including: S1. Perform unbalanced encoding on the communication information bit stream to generate an unbalanced communication code sequence; S2. The unbalanced communication code sequence is fused with a preset ranging pseudocode sequence to obtain an integrated composite code sequence; S3. Based on the integrated composite code sequence, the carrier wave is phase-modulated to output a modulated wave signal; S4. Demodulate the modulated wave signal to obtain a baseband composite code sequence estimate; S5. Perform pseudocode synchronization on the baseband composite code sequence estimation to obtain the measured distance, and perform unbalanced decoding on the baseband composite code sequence estimation to recover the communication information.

[0028] In S1, the communication information bitstream is unbalancedly encoded according to a preset unbalanced encoding rule to generate an unbalanced communication code sequence. The unbalanced encoding rule is as follows: In the communication information bitstream, every m information bits are mapped to an encoding unit of length n. Each encoding unit contains exactly w symbols that are second logic values, and the remaining (nw) symbols are first logic values. Here, n and w are positive integers, satisfying n = w*(k+1), m ≤ log2(C(n, w)), k>0, and C is a combinatorial function. This encoding unit is denoted as the unbalanced communication code sequence. The ratio of the number of symbols for the first logic value to the number of symbols for the second logic value is a preset fixed value p, where p>1.

[0029] More specifically, w=1, and the unbalanced coding rule is as follows: each log2(k+1) information bits is mapped to a coding unit of length (k+1), and the position of the unique second logical value symbol in this coding unit is used to uniquely represent the value of the log2(k+1) information bits. The coding process also includes a step of channel error correction on the communication information bit stream.

[0030] In S2, fusing the unbalanced communication code sequence with a preset ranging pseudocode sequence to obtain an integrated composite code sequence includes: performing a sample-by-sample XOR operation on the unbalanced communication code sequence and the preset ranging pseudocode sequence to obtain the integrated composite code sequence.

[0031] In S3, the step of performing phase modulation on the carrier based on the integrated composite code sequence and outputting a modulated wave signal includes: when the integrated composite code sequence is a first logic value, applying a first preset phase offset to the carrier and outputting a modulated wave signal after the first preset phase offset; when the integrated composite code sequence is a second logic value, applying a second preset phase offset to the carrier and outputting a modulated wave signal after the second preset phase offset.

[0032] Specifically, the carrier is a laser carrier or a microwave carrier.

[0033] In S4, the demodulation of the modulated wave signal to obtain the baseband composite code sequence estimate includes: S41. Interfere the modulated wave signal with a preset local oscillator signal to obtain an interference wave signal; S42. The interference wave signal is converted into an electrical signal by a detector, and then the electrical signal is amplified and converted from analog to digital to obtain a digital signal; S43. Perform digital down-conversion and carrier phase tracking on the digital signal to obtain a baseband signal; S44. Perform symbol timing synchronization and decision-making on the baseband signal to obtain the baseband composite code sequence estimate.

[0034] In S5, the step of obtaining the measured distance by pseudocode synchronization of the baseband composite code sequence estimation includes: S51. Perform cross-correlation calculation between the baseband composite code sequence estimate and the local ranging pseudocode sequence to obtain the correlation value; S52. When the correlation value exceeds a preset threshold, a delay-locked loop is used to generate a leading pseudocode copy and a lagging pseudocode copy, and cross-correlation operations are performed with the baseband composite code sequence estimate to obtain the leading correlation function and the lagging correlation function. S53. An error signal is generated from the difference between the leading correlation function and the lagging correlation function. The generated phase of the local ranging pseudocode sequence is aligned with the received pseudocode sequence based on the feedback control of the error signal. The original phase difference between the local ranging pseudocode sequence and the received pseudocode sequence is output. S54. Calculate the measured distance using the original phase difference.

[0035] Specifically, the step of performing unbalanced decoding to recover communication information from the baseband composite code sequence estimation includes: S55. Perform a sample-by-sample XOR operation on the local ranging pseudocode sequence synchronized with the baseband composite code sequence estimate to obtain the unbalanced communication code sequence estimate. S56. Perform inverse mapping on the estimated unbalanced communication code sequence to obtain the bit stream of communication information.

[0036] More specifically, the step of inversely mapping the estimated unbalanced communication code sequence to obtain the communication information bitstream includes: S561. Divide the unbalanced communication code sequence estimate into multiple code segments according to n information bits; S562. Detect a unique pair of consecutive second logic value segments in each code segment and determine the starting position index of the second logic value segments; S563. Based on the starting position index, determine the corresponding m information bits according to the preset mapping relationship; S564. Concatenate the m information bits corresponding to each code segment in sequence to obtain the bit stream of the communication information.

[0037] Example 2 This embodiment further illustrates the above embodiments. Taking inter-satellite laser ranging and communication as an example, a laser is selected as the carrier. An integrated inter-satellite laser ranging and communication system can be designed using the method in Embodiment 1. This system includes a transmitter and a receiver, and its overall structure is as follows: Figure 2 As shown, the system is a dual single-pass ranging, two-way communication system, with one side serving as the transmitter and the other as the receiver. The system's workflow is as follows: the transmitting satellite encodes the communication information bitstream to be transmitted through unbalanced encoding, performs an XOR operation with the ranging pseudocode sequence to generate a composite code, and then loads it onto a laser carrier via an electro-optic phase modulator for transmission; the receiving satellite receives the optical signal, performs coherent detection and demodulation, recovers the baseband composite code sequence, achieves high-precision distance measurement through pseudocode synchronization, and recovers the communication information through decomposite decoding and unbalanced decoding.

[0038] Step 1: Perform unbalanced coding on the communication information bit stream This embodiment employs an unbalanced encoding scheme, the core of which is to ensure that the number of "0"s (first logic values) in the encoded sequence is far greater than the number of "1"s (second logic values). The specific rules are as follows: every three consecutive information bits are mapped to an encoding unit of 16 sampling points. In this encoding unit, there are exactly two symbols that are "1", and the remaining 14 symbols are "0". The positions of the two "1"s must be consecutive (i.e., forming an "11" segment), and this segment has eight possible starting positions among the 16 positions (starting indices are 0, 2, 4, ..., 14), which correspond one-to-one with the eight combinations of three information bits (000 to 111).

[0039] After this encoding, the symbol rate of the communication code is the sampling frequency divided by 16, which is 6.25MHz. Since each symbol carries 3 information bits, the original communication information rate is the symbol rate multiplied by 3, which is 18.75Mbps.

[0040] Step 2: Generate ranging pseudocode sequence Compared to Figure 3 The traditional encoding structure shown in this embodiment is as follows: Figure 4 As shown, the ranging pseudocode has a length of 1024 bits, obtained by padding a 1023-bit m-sequence (maximum-length linear feedback shift register sequence) with zeros. To meet the needs of subsequent digital processing, the system sampling clock frequency is set to 100MHz. Each pseudocode chip is sampled 32 times, therefore the chip rate of the pseudocode is 3.125MHz.

[0041] Step 3: Generate an integrated composite code sequence Perform a sample-by-sample XOR operation between the unbalanced communication code sequence output from step 1 and the ranging pseudocode sequence output from step 2. The resulting integrated composite code sequence is still a 100MHz binary sequence.

[0042] Step 4: Laser Phase Modulation and Emission The integrated composite code sequence is fed into the electro-optic phase modulator at the transmitter. The modulator operates in binary phase-shift keying mode: when the composite code is 0, the output light phase is 0.5 rad; when the composite code is 1, the output light phase is -0.5 rad. The modulated laser is then collimated by a telescope and transmitted towards the opposite satellite. This low-depth modulation can largely preserve the interferometric capabilities of the laser carrier itself.

[0043] Step 5: Optical Signal Reception and Interference The telescope on the opposite satellite receives the laser signal from the transmitting satellite and interferes with it against the local oscillator light output from its local laser. The interfering optical signal is converted into an electrical signal by a photodetector and then amplified. Subsequently, the signal is digitized by an analog-to-digital converter at a sampling rate of 100MHz.

[0044] Step 6: Digital demodulation and baseband composite code sequence estimation The digitized signal undergoes digital down-conversion and carrier synchronization. In this embodiment, a digital phase-locked loop is used to track the carrier phase and demodulate the in-phase component of the baseband signal. Symbol timing synchronization and decision-making are then performed on this component to obtain a hard-decision estimate of the integrated baseband composite code sequence.

[0045] Step 7: Pseudocode Synchronization and High-Precision Distance Measurement This step is the core of the ranging function, and it is divided into two stages: coarse acquisition and fine tracking.

[0046] Coarse Acquisition: The local pseudocode generator produces the same pseudocode sequence as the transmitter. A sliding cross-correlation operation is performed between the local pseudocode sequence and the received baseband composite code sequence. Acquisition is considered successful when the correlation value exceeds a preset threshold. The correlation function curve is shown below. Figure 5 and Figure 6 As shown, compared to the autocorrelation function of the traditional scheme, its central correlation peak and the two sides produce a step-like shape, but it can still be captured.

[0047] Fine tracking: A delay-locked loop (PLL) is used for fine tracking. This loop generates two copies of the local pseudocode, advancing and delaying them by half a symbol, respectively, resulting in a lead local code and a lag local code. These copies are then correlated with the received pseudocode signal to obtain two correlation functions. Subtracting these correlation functions yields the error signal. The error signal curve in this scheme is shown below. Figure 7 As shown, the vertical axis represents the calculated error signal value, and the horizontal axis represents the phase difference between the received pseudocode and the local pseudocode due to inter-satellite transmission delay. The center position of the error signal is similar to that of traditional schemes, exhibiting a ramp-like shape, indicating a linear relationship between the error signal value and the inter-satellite transmission delay within this range. Therefore, the generation phase of the local pseudocode sequence can be controlled based on the error signal feedback, aligning the local pseudocode with the received pseudocode, thereby achieving accurate phase tracking of the received pseudocode. In a stable tracking state, the inter-satellite transmission delay can be determined from the original phase difference between the local pseudocode and the received pseudocode, and multiplied by the speed of light to calculate the absolute inter-satellite distance.

[0048] Step 8: Decomposition to obtain communication code sequence estimation Perform a sample-by-sample XOR operation on the local pseudocode sequence that has been accurately synchronized in step 7 and the baseband composite code sequence estimate to restore the estimated value of the unbalanced communication code sequence.

[0049] Step 9: Unbalanced decoding to recover communication information The recovered communication code sequence is reverse-mapped according to the encoding rules of the transmitting end. First, it is segmented at intervals of 16 sampling points. For each segment, the starting position index of the unique pair of consecutive 1s is detected. Based on this starting position, the original 3 information bits can be recovered. All segmented decoding results are concatenated in sequence to obtain the complete communication information bit stream.

[0050] Figure 8 This is the power amplitude spectrum of the new coding scheme. It can be seen that it has a low-frequency suppression effect, making it suitable for space science missions where the main interference phase signal undertakes the measurement task.

[0051] This embodiment provides a pseudocode ranging and communication integrated system based on a novel coding scheme to overcome the drawback of existing technologies where the communication code rate is difficult to exceed the ranging pseudocode code rate. The highlights of this embodiment are: the use of a new coding method that ensures the correlation of the pseudocode remains intact to maintain the ranging function even when the communication code rate exceeds the ranging pseudocode code rate. Furthermore, it features low-frequency components and applicability to low-depth modulation, making it particularly suitable for use in space science missions where the main interferometric phase signal plays a primary measurement role, such as space gravitational wave detection missions.

[0052] Example 3 like Figure 9 As shown, this embodiment provides an integrated ranging and communication system, including: The unbalanced encoding module is used to perform unbalanced encoding on the communication information bit stream to generate an unbalanced communication code sequence. A composite code generation module is used to fuse the unbalanced communication code sequence with a preset ranging pseudocode sequence to obtain an integrated composite code sequence. The phase modulation module is used to perform phase modulation on the carrier wave based on the integrated composite code sequence and output a modulated wave signal; The signal demodulation module is used to demodulate the modulated wave signal to obtain a baseband composite code sequence estimate; The composite code processing module is used to perform pseudocode synchronization on the baseband composite code sequence estimation to obtain the measured distance, and to perform unbalanced decoding on the baseband composite code sequence estimation to recover the communication information.

[0053] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for integrating ranging and communication, characterized in that, include: S1. Perform unbalanced encoding on the communication information bit stream to generate an unbalanced communication code sequence; S2. The unbalanced communication code sequence is fused with a preset ranging pseudocode sequence to obtain an integrated composite code sequence; S3. Based on the integrated composite code sequence, the carrier wave is phase-modulated to output a modulated wave signal; S4. Demodulate the modulated wave signal to obtain a baseband composite code sequence estimate; S5. Perform pseudocode synchronization on the baseband composite code sequence estimation to obtain the measured distance, and perform unbalanced decoding on the baseband composite code sequence estimation to recover the communication information.

2. The integrated ranging and communication implementation method according to claim 1, characterized in that, The communication information bitstream is unbalancedly encoded according to a preset unbalanced encoding rule to generate an unbalanced communication code sequence. The unbalanced encoding rule is as follows: In the communication information bit stream, every m information bits are mapped to an encoding unit of length n. In the encoding unit, there are exactly w symbols that are second logic values, and the remaining (nw) symbols are first logic values. Here, n and w are positive integers, and satisfy n = w*(k+1), m ≤ log2(C(n, w)), k>0, and C is a combinatorial function. The encoding unit is denoted as the unbalanced communication code sequence.

3. The integrated ranging and communication implementation method according to claim 2, characterized in that, The ratio of the number of symbols in the first logic value to the number of symbols in the second logic value is a preset fixed value p, and p > 1.

4. The integrated ranging and communication implementation method according to claim 1, characterized in that, The step of fusing the unbalanced communication code sequence with a preset ranging pseudocode sequence to obtain an integrated composite code sequence includes: performing a sample-by-sample point XOR operation on the unbalanced communication code sequence and the preset ranging pseudocode sequence to obtain the integrated composite code sequence.

5. The integrated ranging and communication implementation method according to claim 3, characterized in that, The step of performing phase modulation on the carrier based on the integrated composite code sequence and outputting a modulated wave signal includes: when the integrated composite code sequence is a first logic value, applying a first preset phase offset to the carrier and outputting a modulated wave signal after the first preset phase offset; when the integrated composite code sequence is a second logic value, applying a second preset phase offset to the carrier and outputting a modulated wave signal after the second preset phase offset.

6. The integrated ranging and communication implementation method according to claim 1, characterized in that, The demodulation of the modulated wave signal to obtain the baseband composite code sequence estimate includes: S41. Interfere the modulated wave signal with a preset local oscillator signal to obtain an interference wave signal; S42. The interference wave signal is converted into an electrical signal by a detector, and then the electrical signal is amplified and converted from analog to digital to obtain a digital signal; S43. Perform digital down-conversion and carrier phase tracking on the digital signal to obtain a baseband signal; S44. Perform symbol timing synchronization and decision on the baseband signal to obtain the baseband composite code sequence estimate.

7. The integrated ranging and communication implementation method according to claim 6, characterized in that, The step of obtaining the measured distance by pseudocode synchronization of the baseband composite code sequence estimation includes: S51. Perform cross-correlation calculation between the baseband composite code sequence estimate and the local ranging pseudocode sequence to obtain the correlation value; S52. When the correlation value exceeds a preset threshold, a delay-locked loop is used to generate a leading pseudocode copy and a lagging pseudocode copy, and cross-correlation operations are performed with the baseband composite code sequence estimate to obtain the leading correlation function and the lagging correlation function. S53. An error signal is generated from the difference between the leading correlation function and the lagging correlation function. The generated phase of the local ranging pseudocode sequence is aligned with the received pseudocode sequence based on the feedback control of the error signal. The original phase difference between the local ranging pseudocode sequence and the received pseudocode sequence is output. S54. Calculate the measured distance using the original phase difference.

8. The integrated ranging and communication implementation method according to claim 7, characterized in that, The step of performing unbalanced decoding to recover communication information from the baseband composite code sequence includes: S55. Perform a sample-by-sample XOR operation on the local ranging pseudocode sequence synchronized with the baseband composite code sequence estimate to obtain the unbalanced communication code sequence estimate. S56. Perform inverse mapping on the estimated unbalanced communication code sequence to obtain the bit stream of communication information.

9. The integrated ranging and communication implementation method according to claim 8, characterized in that, The step of inversely mapping the estimated unbalanced communication code sequence to obtain the communication information bit stream includes: S561. Divide the unbalanced communication code sequence estimate into multiple code segments according to n information bits; S562. Detect a unique pair of consecutive second logic value segments in each code segment and determine the starting position index of the second logic value segments; S563. Based on the starting position index, determine the corresponding m information bits according to the preset mapping relationship; S564. Concatenate the m information bits corresponding to each code segment in sequence to obtain the bit stream of the communication information.

10. A ranging and communication integrated system, characterized in that, include: The unbalanced encoding module is used to perform unbalanced encoding on the communication information bit stream to generate an unbalanced communication code sequence. A composite code generation module is used to fuse the unbalanced communication code sequence with a preset ranging pseudocode sequence to obtain an integrated composite code sequence. The phase modulation module is used to perform phase modulation on the carrier wave based on the integrated composite code sequence and output a modulated wave signal; The signal demodulation module is used to demodulate the modulated wave signal to obtain a baseband composite code sequence estimate; The composite code processing module is used to perform pseudocode synchronization on the baseband composite code sequence estimation to obtain the measured distance, and to perform unbalanced decoding on the baseband composite code sequence estimation to recover the communication information.

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