A multi-base-station 5g-ssb signal rsrp low-altitude target positioning method

Abstract

The application discloses a multi-base station 5G-SSB signal RSRP low-altitude target positioning method, comprising the following steps: S1, reconstructing each single signal in the aliasing signal based on an ECA same-frequency detection algorithm; S2, calculating the SS-RSRP value corresponding to each single reconstructed signal; S3, for a target at different reference positions, calculating the SS-RSRP value corresponding to each target echo signal in the aliasing received signal of the target, and constructing an SS-RSRP database; S4, calculating the standard Euclidean distance between the SS-RSRP data of the target echo signal in the aliasing received signal of the target at a certain actual position and the data in the SS-RSRP database; and S5, calculating the minimum value of the standard Euclidean distance, and positioning the target to a specific reference position point. The application can position the target to a specific reference position point, and as the number of reference positions increases, the positioning error is also reduced.

Description

Technical Field

[0001] This invention relates to the field of external radiation source radar technology, and in particular to a method for RSRP low-altitude target localization using multi-base station 5G-SSB (Synchronization Signal Block) signals. Background Technology

[0002] In recent years, drone technology has become increasingly sophisticated, and the low-altitude economy has flourished. 5G signals offer advantages such as large bandwidth, low latency, strong communication capabilities, and high positioning accuracy, making them well-suited for low-altitude target detection. Based on these advantages, 5G signals are widely used in low-altitude target positioning. However, there are still shortcomings in two aspects:

[0003] (1) When locating traditional terminal targets, the main methods used are TOA / TDOA (time of arrival / time difference of arrival) which measures the time it takes for the transmitted signal to travel to multiple base stations, and AoA (angle of arrival) which measures the received signal by the base station antenna array. This method requires the terminal to have signal transmission capabilities, which places high demands on the terminal. Furthermore, the transmitted electromagnetic waves can cause electromagnetic interference, making it unsuitable for locations with high electromagnetic environment requirements (such as airports). In addition, the transmitted electromagnetic waves cause electromagnetic pollution and pollute the environment.

[0004] (2) For the multi-base station model, the electromagnetic signals in space are more complex, the antenna receives radiation from multiple signals, and the signals of the same frequency cell are difficult to distinguish, and the signal components are mixed.

[0005] (3) Currently, the positioning of external radiation source radar has a large positioning error, and a more accurate external radiation source positioning method is needed to improve the positioning effect.

[0006] Therefore, this study presents a RSRP low-altitude target localization method based on multi-base station 5G-SSB signals, which is of great significance. Summary of the Invention

[0007] Purpose of the invention: This invention proposes a low-altitude target positioning method based on multi-base station 5G-SSB signals using RSRP (Reference Positioning Parameter). This method has low hardware requirements for the target and the positioning error decreases as the number of reference locations increases.

[0008] Technical solution: The RSRP low-altitude target positioning method for multi-base station 5G-SSB signals described in this invention specifically includes the following steps:

[0009] S1. Reconstruct each signal in the aliased signal received by the receiving station based on the ECA co-frequency detection algorithm;

[0010] S2. For all the single signals obtained from the reconstruction, delete the direct wave signal, retain the target echo signal, and calculate the reference signal average received power SS-RSRP value for each target echo.

[0011] S3. For targets at different reference positions, construct an SS-RSRP database consisting of the target echo SS-RSRP values ​​in the corresponding aliased received signals.

[0012] S4. Calculate the standard Euclidean distance between the SS-RSRP data of each target echo of the actual received signal and the data in the SS-RSRP database;

[0013] S5. Take the reference position corresponding to the smallest standard Euclidean distance value as the estimated target position.

[0014] Furthermore, the implementation process of step S1 is as follows:

[0015] First, peak cell detection is performed, PSS coarse synchronization is completed, and the cell group ID number is determined. And the initial synchronization point, the cell group ID number The initial synchronization point is passed to the SSS for synchronization, and then to the PSS for fine synchronization. The PSS fine synchronization further reduces the synchronization point error to obtain the final synchronization point. The auxiliary synchronization signal is then detected by the SSS synchronization mechanism. ;

[0016] Next, PBCH channel decoding is performed, and the above steps yield the results. and Then the physical ID number of the peak cell Represented as:

[0017] ;

[0018] Obtain the physical cell ID of the peak cell and the location of the currently detected SSB beam timing synchronization point, and then perform PBCH decoding.

[0019] Furthermore, step S2 is implemented as follows:

[0020] First, calculate the average received power of the SSS signal module. :

[0021] ;

[0022] in, For the SSB index of the SS burst set. The length of the SSS sequence. This is the set of all subcarrier positions occupied by the SSS signal in the time-frequency resource grid. for The set of all SSS subcarrier indexes in the database. Indicates the index number is SSS module in the SSB sequence at that time;

[0023] Similarly, the average received power of the DM-RS signal module can be calculated:

[0024] ;

[0025] The length of the DM-RS sequence. For index number DM-RS module at the time;

[0026] The size of SS-RSRP is calculated from this. :;

[0027] ;

[0028] in, The length of the DM-RS sequence.

[0029] Furthermore, the aforementioned The range of values ​​is .

[0030] Furthermore, step S3 is implemented as follows:

[0031] The system adopts a three-base station model with a regular hexagonal structure. Each base station covers a 120° sector. Each base station has three signal sources, and each signal source transmits eight SSB beam signals with minimal delay. Each different SSB beam signal transmitted by each base station corresponds to a different direction, and each SSB has a different cell physical ID number.

[0032] For the A reference position, The SS-RSRP sequence received by the receiving station is as follows:

[0033] ;

[0034] in, Indicates the number received by the receiving station The average SS-RSRP matrix of the aliased target echoes corresponding to each reference position This indicates that the receiving station received the first... The first reference position corresponds to the aliased target echo in the 1st reference position The SS-RSRP value at strong signal locations is calculated by averaging 25 times. ;

[0035] Then the SS-RSRP sequences corresponding to all reference positions for:

[0036] .

[0037] Furthermore, step S4 is implemented as follows:

[0038] Since different signals travel at different distances and attenuate at different rates during propagation, the RSRP value of each signal in the aliased signal also changes accordingly. Combining the environmental model, the RSRP value array of the target echo signal reconstructed by the ECA algorithm in the actual received signal is selected, and the standard Euclidean distance value is calculated from the RSRP database measured at different reference positions.

[0039] Furthermore, the implementation process of step S5 is as follows:

[0040] The reference position corresponding to the minimum standard Euclidean distance value is taken as the estimated target position. When the target is located at this reference position in the SS-RSRP database, the extracted target echo SS-RSRP array is closest to the SS-RSRP value of the target echo in the actual receiving signal. This reference position is then used as the estimated target position.

[0041] Beneficial effects: Compared with the prior art, the beneficial effects of this invention are as follows: the target to be located does not need to have the ability to autonomously emit electromagnetic waves, and the hardware requirements of the target to be located are low; the receiving station can determine the location information by analyzing the target echo reflected by the target, without causing electromagnetic pollution or electromagnetic radiation, and is suitable for some extreme scenarios with high electromagnetic requirements (such as airports), and does not cause electromagnetic pollution, making it green and environmentally friendly; at the same time, this invention can locate the target to a specific reference point, and as the number of reference points increases, the positioning error of the target positioning also decreases. Attached Figure Description

[0042] Figure 1 This is a flowchart of the single signal reconstruction and SS-RSRP calculation method in aliased signals;

[0043] Figure 2 This is a diagram of a multi-base station aliasing signal model;

[0044] Figure 3 It is a 5G base station aliasing signal system model based on a three-base station scenario;

[0045] Figure 4 This is the model diagram corresponding to 217 reference positions;

[0046] Figure 5This refers to the positioning accuracy corresponding to different signal-to-noise ratios of the AWGN (Additive White Gaussian Noise) channel when taking 217 reference positions;

[0047] Figure 6 This represents the variation in positioning error at 217 reference positions under different signal-to-noise ratios. Detailed Implementation

[0048] The present invention will now be described in further detail with reference to the accompanying drawings.

[0049] This invention proposes a low-altitude target localization method based on RSRP (Resonance Reduction Point) using multi-base station 5G-SSB signals. The specific implementation process is as follows:

[0050] S1: As Figure 1 As shown, the reconstruction of each individual signal in the aliased signal received by the receiving station is performed based on the Extensive Cancellation Agorithm (ECA).

[0051] After performing complete preprocessing on the aliased signals received by the receiving station, the received signals are reconstructed and eliminated using the ECA co-frequency detection algorithm based on interference cancellation.

[0052] First, peak cell detection is performed to complete coarse synchronization of the PSS (Primary Synchronization Signal) and determine the cell group ID number. And the initial synchronization point, the cell group ID number The initial synchronization point is input to the Secondary Synchronization Signal (SSS) for synchronization, and then to the Precision Synchronization Signal (PSS) for fine synchronization. The PSS fine synchronization further reduces the synchronization point error, resulting in a precise synchronization point. The secondary synchronization signal (SSS) is then used for synchronization detection to obtain... .

[0053] Next, PBCH (Physical Broadcast Channel) channel decoding is performed, and the above steps yield the results. and Then the physical ID number of the peak cell It can be represented as:

[0054]

[0055] After obtaining the physical cell ID of the peak cell and the location of the currently detected SSB beam timing synchronization point, PBCH decoding is performed. During PBCH decoding, CRC check is used to determine whether the signal has been successfully parsed. Frequency offset estimation and adjustment are then performed.

[0056] Based on the cell ID number and MIB information obtained from decoding, the corresponding PSS, SSS, DM-RS and PBCH signals in the peak cell SSB module are reconstructed sequentially. The reconstructed signals are saved for subsequent operations, and interference cancellation is performed on the current signal. The next strongest cell signal is then reconstructed and eliminated, and so on, until all cells in the aliasing signal are detected, i.e., CRC check fails.

[0057] S2: Calculate the SS-RSRP (Synchronization Signal Reference Signal Receiving Power) value for each signal.

[0058] For all the reconstructed individual signals, due to the different frequency offsets of different base stations, frequency offset estimation is performed using the combined PSS and SSS primary and secondary synchronization signals. This yields several groups of signals with similar frequency offsets, each containing direct waves and target echoes from the same base station. Since the direct wave has a shorter propagation distance and higher power, it can be distinguished from the target echo. The stronger direct wave signal is removed, leaving the target echo. The average received power of its SSS module and DM-RS module is calculated separately to obtain the reference signal average received power SS-RSRP value for each target echo in the aliased signal. The specific steps are as follows:

[0059] First, calculate the average received power of the SSS signal module:

[0060]

[0061] in, For the SSB index in the SS burst set, the range of values ​​in this paper is: , Indicates the length of the SSS sequence. This is the set of all subcarrier positions occupied by the SSS signal in the time-frequency resource grid. for The set of all SSS subcarrier indexes in the database. When representing index number The SSS module in the SSB sequence.

[0062] Similarly, the average received power of the DM-RS signal module can be calculated:

[0063]

[0064] Indicates the length of the SSS sequence. When representing index number The DM-RS module.

[0065] Then, the size of SS-RSRP can be calculated. :

[0066]

[0067] in The length of the DM-RS sequence.

[0068] Since RSRP is related to signal power and propagation distance, different signals propagate over different distances and attenuate at different rates during propagation, thus altering the average RSRP of each signal in aliased signals. By combining an environmental model with the closest SS-RSRP value between the received signal reconstructed using the ECA algorithm and the SS-RSRP value measured at different reference locations in the database, the target can be located near that location, significantly improving target localization accuracy.

[0069] S3: Select targets located at different reference positions and construct an SS-RSRP database consisting of the target echo SS-RSRP values ​​in the corresponding received signals.

[0070] Figure 2 This is a diagram illustrating a multi-base station aliasing signal model. Taking a three-base station aliasing signal system model as an example, as shown... Figure 3 As shown, a regular hexagonal structure is adopted, with each base station covering a 120° sector, matching the dense cellular network of current 5G base stations. Each base station has three signal transmitters, each transmitting eight SSB beam signals with minimal delay. Each base station and each different SSB beam signal corresponds to a different direction, and each SSB has a different cell physical ID number. The three base stations can basically achieve full coverage within the regular hexagonal area. For the external radiation source radar receiving station, assuming that multipath clutter and target echoes formed by other targets within the positioning range are ignored, the signals received by the receiving station include direct waves from the external radiation source radar receiving station gNB1 (SSB6), gNB2 (SSB4), and gNB3 (SSB4), as well as target echoes obtained by reflections from targets hit by SSB7 from gNB1, SSB2 from gNB2, and SSB4 from gNB3. Using the coverage area in the three-base station aliasing signal model as the target detection range, several points are uniformly selected as possible reference locations of the target. The SS-RSRP values ​​of each target echo signal in the received signal when the target is located at these locations are calculated according to steps (1) and (2), and an SS-RSRP database is constructed. The specific steps are as follows:

[0071] Ignoring the effects of multipath clutter, the signal received by the receiving station consists of the target echo and the direct wave. Since SS-RSRP measurements of aliased signals generate interference, the aliased SSB beams are separated. Select... A reference location, such as Figure 4 The black dot represents the reference position. A strong direct wave is removed using an ECA co-frequency detection algorithm based on interference cancellation. Then, the target echo SSB beam is reconstructed using cell base station information. The SS-RSRP value is calculated for the reconstructed SSB beam. After eliminating the previously calculated SSB beam interference, the SS-RSRP value of the second strongest SSB beam in the target echo is calculated. Then, for the... A reference position, The SS-RSRP sequence received by the receiving station is as follows:

[0072]

[0073] in, Indicates the number received by the receiving station The average SS-RSRP matrix of the aliased target echoes corresponding to each reference position This indicates that the receiving station received the first... The first reference position corresponds to the aliased target echo in the 1st reference position Average SS-RSRP size at strong signal locations .

[0074] Then the SS-RSRP sequences corresponding to all reference positions for:

[0075]

[0076] S4: Transfer the SS-RSRP data of the actual received signal. Data in the SS-RSRP database Calculate the standard Euclidean distance.

[0077] A target test location is randomly selected, and the signal is reconstructed sequentially using the ECA algorithm. The direct wave is removed, and the SS-RSRP value is calculated for the reconstructed SSB beam. After eliminating the direct wave, the SS-RSRP value of the second strongest signal in the target echo is calculated, thus obtaining the SS-RSRP sequence of the target echo received by the corresponding receiving station at that location. When using a three-base station model, which includes three target echoes, then... for:

[0078]

[0079] This indicates the first aliased target echo received by the receiving station. The SS-RSRP value at strong signal locations, where The SS-RSRP array is used to obtain the target echo signal from a simulated target at a real location. Data corresponding to all reference locations in the SS-RSRP database Calculate the standard Euclidean distance.

[0080] Because different signals travel at different distances and attenuate at different rates during propagation, the RSRP value of each signal in the aliased signal also changes accordingly. Based on an environmental model, the RSRP value array of the target echo signal reconstructed using the ECA algorithm from the actual received signal is selected, along with the standard Euclidean distance value calculated from the RSRP database measured at different reference locations.

[0081] S5: Target the specific point.

[0082] The SS-RSRP values ​​of the three target echoes corresponding to the actual received signals were obtained. SS-RSRP database corresponding to 217 reference locations Then, the standard Euclidean distance is calculated between the SS-RSRP value corresponding to the actual target and the SS-RSRP value corresponding to each reference position in the SS-RSRP database. The reference position corresponding to the minimum standard Euclidean distance is selected. When the target in the SS-RSRP database is located at this reference position, the extracted target echo SS-RSRP array is closest to the SS-RSRP value of the target echo in the actual receiving station signal. That is, this reference position is used as the estimated target position, thereby achieving a more accurate positioning process.

[0083] Assuming a three-base ...

[0084] Table 1 Simulation parameters corresponding to the signals of the three base stations.

[0085]

[0086] By simulating the aliasing signals of three target echoes corresponding to three base stations, traversing... Figure 4 Based on 217 reference positions, a series of process models are constructed to show how different SSB signals are directed toward the target and reflected to the receiving station. These models include signal propagation through the AWGN channel, receiver thermal noise, and signal attenuation during propagation. The target position is estimated after the received signal at each position is processed.

[0087] Figure 5 The probability that the position obtained from the minimum Euclidean distance matches the correct position is calculated based on the average RSRP value of each beam obtained from the measurement and the reference position. Figure 5 It can be seen that when the signal-to-noise ratio is greater than 4dB, the measurement accuracy of the precise point location reaches more than 90%. The higher the signal-to-noise ratio, the higher the accuracy of the positioning position to the actual point.

[0088] During the simulation, several points were randomly selected uniformly within the hexagonal positioning area as the target's true positions for simulation experiments. The average error between the true and predicted positions was calculated, and this positioning error was used as a measure of the positioning effect. 217, 817, 1261, and 3169 reference positions were uniformly selected within the hexagonal region, respectively. Figure 6 The positioning error corresponding to different numbers of reference positions under different signal-to-noise ratios is given by... Figure 6 It can be seen that as the number of reference positions increases and the signal-to-noise ratio continues to rise, the positioning error also decreases accordingly.

[0089] Simulation results show that when 217 reference locations are used and the distance between base stations is 500 meters, the positioning error is 36.4 meters at a signal-to-noise ratio of 15dB, which is relatively small. As the signal-to-noise ratio increases, the positioning error decreases.

[0090] The above content merely illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on this technical solution fall within the scope of protection of the technical concept proposed in this invention and are included in the claims of this invention.

Claims

1. A method for RSRP low-altitude target positioning of multi-base station 5G-SSB signals, characterized in that, The method comprises the following steps: S1, reconstructing each signal in the aliasing signal received by the receiving station based on the ECA same-frequency detection algorithm; S2, deleting the direct wave signal and retaining the target echo signal for each target echo, and calculating the reference signal average received power SS-RSRP value of each target echo; S3, for different reference positions of the target, constructing a SS-RSRP database composed of target echo SS-RSRP values in the aliasing received signal corresponding to the target; S4, calculating the standard Euclidean distance of the SS-RSRP data of each target echo of the actual received signal and the data in the SS-RSRP database; S5, taking the reference position corresponding to the minimum standard Euclidean distance value as the estimated position of the target; The step S3 is implemented as follows: A three-base station model regular hexagonal structure is adopted, and each base station covers an area of 120° sector; each base station has three signal transmission sources, each signal transmission source transmits 8 SSB beam signals with a very small time delay; each different SSB beam signal transmitted by each base station corresponds to a different direction, and each SSB has a different cell physical ID number; The sequence of SS-RSRP received by the receiving station for the first reference position, is: ； in, Indicates the number received by the receiving station The average SS-RSRP matrix of the aliased target echoes corresponding to each reference position This indicates that the receiving station received the first... The first reference position corresponds to the aliased target echo in the 1st reference position The SS-RSRP value at strong signal locations is calculated by averaging 25 times. ; then all the reference locations corresponding to the SS-RSRP sequence is: ； The step S4 is implemented as follows: Because the distances of different signals are different, the signals attenuate differently during propagation, and the RSRP value of each signal in the aliasing signal also changes; in combination with the environment model, the RSRP value array of the target echo signal reconstructed by the ECA algorithm in the actual received signal is selected, and the standard Euclidean distance value is calculated by measuring the RSRP database of different reference positions.

2. The RSRP low-altitude target positioning method of a multi-base-station 5G-SSB signal according to claim 1, characterized in that, The step S1 is implemented as follows: First, peak cell detection is performed, PSS coarse synchronization is completed, and intra-cell group ID number is determined and initial synchronization point, the intra-cell group ID number is transmitted into SSS synchronization, the initial synchronization point is transmitted into PSS fine synchronization; the PSS fine synchronization further reduces the synchronization point error to obtain the fine synchronization point; the secondary synchronization signal SSS synchronization detection is performed to obtain ; PBCH channel decoding is then performed on the above step to obtain and the physical ID number of the peak cell is expressed as: ； The physical cell ID number of the peak cell and the SSB beam timing synchronization point position of the currently detected SSB beam are obtained, and PBCH decoding is performed.

3. The RSRP low-altitude target positioning method of a multi-base-station 5G-SSB signal according to claim 1, characterized in that, The step S2 is implemented as follows: First, the average received power of the SSS signal module is calculated : ； wherein, is an index of a SSB in a SS burst set, is a length of a SSS sequence, is a set of all subcarrier locations occupied by a SSS signal in a time-frequency resource grid, is all SSS subcarrier index sets in denotes an SSS module in a SSB sequence with index number ; The average received power of the DM-RS signal module is calculated: ； is the length of the DM-RS sequence, is the index number of the DM-RS module when is the DM-RS module when The size of the SS-RSRP is thus calculated : ； wherein, is the length of the DM-RS sequence.

4. The RSRP low-altitude target positioning method of a multi-base-station 5G-SSB signal according to claim 3, characterized in that, The ranges from .

5. The RSRP low-altitude target positioning method of a multi-base-station 5G-SSB signal according to claim 1, characterized in that, The step S5 is implemented as follows: When the target in the SS-RSRP database is located at the reference position, the target echo SS-RSRP array extracted is most similar to the SS-RSRP value of the target echo in the actual received signal, and the reference position is taken as the estimated target position.

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