Indoor positioning system and method based on passive indoor distribution

Abstract

The invention provides an indoor positioning system and method based on passive indoor distribution, and the method comprises the steps: deploying two sets of antennas outdoors, receiving a frequency 1 signal through a feed-in point 1, receiving a frequency 2 signal through a feed-in point 2, carrying out the amplification and filtering of the two signals through a satellite signal processing unit, and reserving a target frequency band; a frequency 1 signal and a base station information source are combined into an A-path signal, the length # imgabs0 # of each branch is covered and recorded through an indoor distribution system, a frequency 2 signal is independently transmitted as a B-path signal, the length of each branch is recorded as # imgabs1 #, and a time delay unit is configured to adjust signal synchronization; the method comprises the following steps: acquiring a pseudo-range difference between A and B paths of signals, establishing a coarse-grained fingerprint database of region matching, and combining geomagnetic sequence data to construct a high-precision fine-grained fingerprint database; the area is preliminarily determined through pseudo-range difference matching, and then terminal coordinates are accurately positioned according to geomagnetic data. According to the scheme, through dual-frequency signal fusion and layered fingerprint matching, the problem of satellite signal shielding in a complex scene is solved, and the positioning precision and reliability are improved.

Description

Technical Field

[0001] The present invention relates to the technical fields of wireless communication and positioning, and particularly to an indoor positioning system and method based on passive indoor distribution, which is applicable to precise positioning in satellite signal shielding areas such as large buildings and underground spaces. Background Art

[0002] With the rapid development of the Internet of Things technology and the in-depth promotion of the construction of smart cities, indoor positioning technology, as an important branch in the field of location services, is facing increasing application demands. In complex indoor environments such as large commercial complexes, underground parking lots, and industrial factories, precise location information services have become the basic support for key applications such as intelligent navigation, asset tracking, and emergency rescue. The current technical system mainly focuses on two directions: the deployment of active devices and the utilization of passive signals, but both face significant technical bottlenecks in practical applications. The existing positioning technologies mainly include: First, the positioning technology based on active devices is represented by Wi-Fi fingerprint recognition and Bluetooth beacon (Beacon) systems, which constitute the current mainstream indoor positioning solutions. Wi-Fi fingerprint positioning realizes position estimation by establishing a mapping database between signal strength (RSSI) and spatial positions and using pattern matching algorithms. The Bluetooth beacon system relies on a positioning network composed of low-power Bluetooth devices and realizes trilateration positioning by receiving signal strength for ranging. Although these two types of technologies have achieved certain applications in scenarios such as hospital navigation and mall shopping guides, they both require the deployment of dedicated signal transmitting devices, resulting in high system construction costs.

[0003] Second, the Global Navigation Satellite System (GNSS), as the core technology for outdoor positioning, faces fundamental physical limitations in indoor environments. When electromagnetic waves penetrate building structures, the satellite signal frequency band attenuates when passing through reinforced concrete walls, resulting in a sharp reduction in the number of effective satellite signals.

[0004] Third, as an important branch of passive positioning, geomagnetic positioning technology uses the spatial heterogeneity characteristics of the earth's magnetic field for position matching. Its technical advantage lies in that it does not require the deployment of dedicated equipment and can directly use the built-in magnetometer of a smartphone to achieve the positioning function. However, the inherent characteristics of the geomagnetic field lead to essential limitations of this technology: the continuity of geological structures makes the magnetic field gradient change gently, and the magnetic field intensity difference in open areas may be less than 100 nT / m², which directly restricts the spatial resolution of the matching algorithm. In modern buildings with similar building materials, the magnetic anomalies generated by steel structures often show a spatially symmetric distribution, resulting in a similarity of magnetic field characteristics at different positions exceeding 80%, making the positioning system prone to mis-matching.

[0005] Based on the deficiencies in the existing technologies, it is necessary to provide a technical solution that can achieve low cost, comprehensive GNSS signal coverage, and precise positioning. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention provides an indoor positioning system and method based on passive distributed antenna system (DAS), which is applicable to precise positioning in satellite signal shielding areas such as large buildings and underground spaces. The specific implementation is as follows: On the one hand, an embodiment of the present invention provides an indoor positioning system based on passive DAS. The system includes: a satellite receiving antenna, a single-frequency satellite signal processing unit, a time delay configuration unit, a base station signal source, a combiner, a passive indoor distribution system, cloud services, and a positioning terminal, where: The satellite receiving antenna is installed in an outdoor open area and is used to receive satellite signals and transmit the received satellite signals to the single-frequency satellite signal processing unit; The single-frequency satellite signal processing unit is used to amplify and filter the satellite signals received by the satellite receiving antenna, and then retain the satellite signals in a specific frequency band; The time delay configuration unit is used to adjust the time delay of the satellite signals. By configuring and introducing precise time delay amounts, the range of satellite signal difference eigenvalues between different branch-level regions does not overlap, having distinguishability; The base station signal source is used to provide a signal source in the communication network; The combiner is a specific device located between the base station signal source and the passive indoor distribution system, and is used to combine the downlink signals of the base station signal source and output them to the antenna feeder equipment of the passive indoor distribution system. At the same time, in the reverse direction, it splits the uplink signals from the antenna feeder equipment and outputs them to each system signal source; The passive indoor distribution system (Passive DAS) usually uses a remote radio unit (RRU) or a repeater as the signal source, splits and distributes the signals through passive devices (such as power dividers and couplers), and transmits them to indoor antennas using coaxial cables. The passive devices do not require external power supply; Further, the passive devices include power dividers, couplers, combiners, etc.; The cloud services are deployed on cloud servers and include an ephemeris information service unit and a differential information service unit. The ephemeris information service unit provides an ephemeris information data download service for the positioning terminal; the differential information service unit provides real-time differential information for the positioning terminal; Further, the ephemeris information is information describing the satellite motion orbit, including satellite orbit parameters relative to a certain reference epoch and necessary orbit perturbation correction item parameters; the differential information is collected by one or more reference stations (also called reference stations) with known precise positions and includes various types of data, such as pseudorange differential correction amounts, carrier phase differential correction amounts, etc.

[0007] The positioning terminal has a positioning function and integrates one or more of a GNSS signal receiving module, a geomagnetic sensor, and an inertial sensor.

[0008] On the other hand, an embodiment of the present invention provides an indoor positioning method based on passive indoor distribution, which is applied to the above-mentioned indoor positioning system based on passive indoor distribution. The method includes: Step 1: Based on the positions of two different feeding points, use two outdoor satellite receiving antennas to receive satellite signals. The received satellite signals are amplified and filtered by a satellite signal processing unit, and satellite signals in a specific frequency band are retained. The satellite signal of frequency 1 is retained at feeding point 1, and the satellite signal of frequency 2 is retained at feeding point 2; Step 2: Feed the satellite signal of frequency 1 and the base station signal source into the indoor distribution antenna system through a combiner as the A-path signal, and record the lengths of each branch of the A-path signal as ; Step 3: Feed the satellite signal of frequency 2 into the indoor distribution antenna system as the B-path signal, and record the lengths of each branch of the B-path signal , and set a time delay configuration unit in different branches; Step 4: Based on the A-path signal and the B-path signal in the positioning area, collect the pseudorange difference between the A-path signal and the B-path signal as the coarse-grained fingerprint for positioning area matching, and collect the geomagnetic sequence in the positioning area as the fine-grained fingerprint for position matching; Step 5: Based on the collected coarse-grained fingerprint for positioning area matching, match the coarse-grained fingerprint in the sample library to preliminarily determine the area where the terminal is located; Step 6: According to the terminal sensor data, match the fine-grained fingerprint in the sample library to further determine the position of the terminal.

[0009] Further, in Step 3, further, the purpose of setting the time delay configuration unit in different branches is to make the range of the satellite signal difference characteristics between the same branch-level regions non-overlapping and distinguishable; its time delay configuration should satisfy the expression:

[0010] In the formula: represents the branch; is a natural number representing the number of branches; represents the speed of light; represents the transmission speed coefficient of electromagnetic waves in the indoor distribution feeder; represents the th branch delay; represents the th branch delay; represents the time delay difference between adjacent branches.

[0011] Further, in step 4, based on the A-path signal and the B-path signal within the positioning area, the pseudorange difference between the A-path signal and the B-path signal is collected, and the pseudorange difference The calculation expression is:

[0012] In the formula, represents the horizontal floor coordinate The pseudorange difference between the A-path signal and the B-path signal at the position; are the corrected pseudorange values of the A-path satellite signal and the B-path satellite signal at this position, respectively; are the original pseudorange values of the A-path satellite signal and the B-path satellite signal at this position, respectively; and are the pseudorange correction amounts of the A-path satellite signal and the B-path satellite signal based on the reference station, respectively; is the pseudorange correction amount caused by the transmission time of the A-path satellite signal from the outdoor receiving antenna to the output port of the combiner, which can be obtained by measurement; is the pseudorange correction amount caused by the transmission time of the B-path satellite signal from the outdoor receiving antenna to the output port of the single-frequency satellite signal processing unit, which can be obtained by measurement; The geomagnetic sequence within the positioning area The expression is:

[0013] In the formula, is the horizontal floor coordinate The modulus value of the magnetic field signal sample at the position, that is, the magnetic field modulus value.

[0014] Further, in step 5, based on the coarsely grained fingerprint matched with the collected positioning area, the coarsely grained fingerprint in the sample library is matched, specifically including: Based on the pseudorange difference between the A-path signal and the B-path signal at each coordinate point within the positioning area and the pseudorange difference in the sample library, the signal feature distance is calculated to obtain a signal feature distance set; Select the smallest m coordinate set of pseudorange difference sample values in the signal feature distance set to preliminarily determine the area where the terminal is located.

[0015] Further, the calculation formula of the signal feature distance is as follows:

[0016] In the formula, represents the pseudorange difference sample of the corresponding coordinate point; is a natural number representing the number of pseudorange difference samples.

[0017] Further, in step 6, the terminal sensor data includes data such as acceleration, angular velocity, and magnetic field; the matching of the fine-grained fingerprint in the sample library based on the terminal sensor data and further determining the location of the terminal specifically includes: Based on the preliminary determination of the area where the terminal is located, the position point with the smallest signal feature distance will be selected as the starting point, and the relative motion trajectory set is calculated in combination with the terminal sensor data ; Based on the relative motion trajectory set, a geomagnetic sequence set to be matched is constructed ; For the sample geomagnetic sequence calculate the magnetic field feature distance with each geomagnetic sequence in the geomagnetic sequence set to be matched; Select the sample sequence coordinates with the smallest magnetic field feature distance as the terminal trajectory, and then determine the current location of the terminal.

[0018] Further, the calculation formula of the magnetic field distance is as follows:

[0019] In the formula, represents the pseudorange difference sample of the corresponding coordinate point; is a natural number, representing the number of pseudorange difference samples; represents the coordinate point corresponding to the geomagnetic sequence; is a natural number, representing the number of geomagnetic sequence coordinate points.

[0020] Compared with the prior art, the present invention has the following advantages: In the present invention, satellite signals are introduced into the in-building distribution system through different feeding points, and the signal difference characteristics of different branches are used as fingerprints to distinguish terminal areas for terminal area identification. At the same time, on the basis of area identification, geomagnetic sequence positioning is fused. Different position points on the isogram of the satellite signal difference characteristic values in the area are used as reference points for the geomagnetic sequence to be matched to construct the geomagnetic sequence to be matched, and they are respectively matched and calculated with the real-time measured geomagnetic sequence values of the terminal to further identify the fine-grained position of the terminal and improve the positioning accuracy.

[0021] Other features and advantages of the present invention will be described in the subsequent description, and some of them will become obvious from the description or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the description, the claims, and the drawings. Brief Description of the Drawings

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a structural diagram of an indoor positioning system based on passive distributed antenna system (DAS).

[0024] Figure 2 It is a flowchart of an indoor positioning method based on passive DAS.

[0025] Figure 3 It is a schematic structural diagram of an indoor positioning method based on passive DAS. Specific embodiments

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0027] In one embodiment, please refer to Figure 1 , a kind of indoor positioning system based on passive DAS is provided. The system includes a satellite receiving antenna, a single-frequency satellite signal processing unit, a time delay configuration unit, a base station signal source, a combiner, a passive indoor distribution system, cloud service, and a positioning terminal, where: The satellite receiving antenna is installed in an outdoor open area and is used to receive satellite signals and transmit the received satellite signals to the single-frequency satellite signal processing unit; The single-frequency satellite signal processing unit is used to amplify and filter the satellite signals received by the satellite receiving antenna, and then retain the satellite signals in a specific frequency band; The time delay configuration unit is used to adjust the time delay of the satellite signals. By configuring and introducing accurate time delay amounts, the range of satellite signal difference eigenvalues between different branch-level regions does not overlap and has distinguishability; The base station signal source is used to provide a signal source in the communication network; The combiner is a specific device located between the base station signal source and the passive indoor distribution system. It is used to combine the downlink signals of the base station signal source and output them to the antenna feeder device of the passive indoor distribution system. At the same time, it splits the uplink signals from the antenna feeder device in the reverse direction and outputs them to each system signal source; A passive in-building distribution system (Passive DAS) usually uses a remote radio unit (RRU) or a repeater as the signal source. The signal is split and distributed by passive devices (such as power dividers and couplers), and transmitted to indoor antennas through coaxial cables. The passive devices do not require external power supply. Further, the passive devices include power dividers, couplers, combiners, etc. Cloud service is deployed on cloud servers and includes an ephemeris information service unit and a differential information service unit. The ephemeris information service unit provides ephemeris information data download service for positioning terminals; the differential information service unit provides real-time differential information for positioning terminals. Further, the ephemeris information is information describing the satellite's motion orbit, including satellite orbit parameters relative to a certain reference epoch and necessary orbit perturbation correction item parameters; the differential information is collected by one or more reference stations (also called reference stations) with known precise positions and includes various types of data, such as pseudorange differential corrections, carrier phase differential corrections, etc.

[0028] A positioning terminal has a positioning function and integrates one or more of a GNSS signal receiving module, a geomagnetic sensor, and an inertial sensor.

[0029] In one embodiment, please refer to Figure 2 and Figure 3 , a method for indoor positioning based on passive in-building distribution is provided. The method includes the following steps: Step S1: Based on two different feeder point positions, use two outdoor satellite receiving antennas to receive satellite signals. The received satellite signals are amplified and filtered by a satellite signal processing unit, and satellite signals in a specific frequency band are retained. Frequency 1 satellite signal is retained at feeder point 1, and frequency 2 satellite signal is retained at feeder point 2. Step S2: Feed the frequency 1 satellite signal and the base station source signal into the in-building distribution antenna system through a combiner as the A-path signal, and record the lengths of each branch of the A-path signal as ; Step S3: Feed the frequency 2 satellite signal into the in-building distribution antenna system as the B-path signal, and record the lengths of each branch of the B-path signal , and set a time delay configuration unit in different branches. Further, the purpose of setting the time delay configuration unit in different branches is to make the satellite signal difference eigenvalue ranges between different branch-level regions non-overlapping and distinguishable; its time delay configuration should satisfy the expression:

[0030] In the formula: represents a branch; is a natural number representing the number of branches; represents the speed of light; represents the transmission speed coefficient of the electromagnetic wave in the indoor distribution feeder; represents the time delay of the represents the time delay of the represents the time delay difference between adjacent branches.

[0031] Step S4: Based on the A-path signal and the B-path signal in the positioning area, collect the pseudorange difference between the A-path signal and the B-path signal as the coarse-grained fingerprint for positioning area matching, and collect the geomagnetic sequence in the positioning area as the fine-grained fingerprint for position matching; Furthermore, for the collection of the pseudorange difference between the A-path signal and the B-path signal based on the A-path signal and the B-path signal in the positioning area, the pseudorange difference The calculation expression is:

[0032] In the formula, represents the horizontal floor coordinate of the pseudorange difference between the A-path signal and the B-path signal at the are respectively the corrected pseudorange values of the A-path satellite signal and the B-path satellite signal at this position; are respectively the original pseudorange values of the A-path satellite signal and the B-path satellite signal at this position; , are respectively the pseudorange correction amounts of the A-path satellite signal and the B-path satellite signal based on the reference station; is the pseudorange correction amount caused by the transmission time of the A-path satellite signal from the outdoor receiving antenna to the output port of the combiner, which can be obtained by measurement; is the pseudorange correction amount caused by the transmission time of the B-path satellite signal from the outdoor receiving antenna to the output port of the single-frequency satellite signal processing unit, which can be obtained by measurement.

[0033] Furthermore, the geomagnetic sequence in the positioning area has the following expression:

[0034] In the formula, is the horizontal floor coordinate of the modulus value of the magnetic field signal sample at the

[0035] Step S5: Based on the collected coarse-grained fingerprint for positioning area matching, match the coarse-grained fingerprint in the sample library to preliminarily determine the area where the terminal is located; Furthermore, the matching of the collected coarse-grained fingerprint for positioning area matching with the coarse-grained fingerprint in the sample library specifically includes: Step S501: Calculate the signal feature distance based on the pseudorange difference between the A-path signal and the B-path signal at each coordinate point within the positioning area and the pseudorange difference in the sample library, to obtain a set of signal feature distances; Further, the signal feature distance is calculated by the following formula:

[0036] In the formula, represents the pseudorange difference sample corresponding to the coordinate point; is a natural number representing the number of pseudorange difference samples.

[0037] Step S502: Select the set of coordinates of the m smallest time delay difference sample values in the set of signal feature distances, and preliminarily determine the area where the terminal is located.

[0038] Step S6: According to the terminal sensor data, match the fine-grained fingerprints in the sample library to further determine the location of the terminal.

[0039] Further, the terminal sensor data includes data such as acceleration, angular velocity, and magnetic field; Further, the process of matching the fine-grained fingerprints in the sample library according to the terminal sensor data to further determine the location of the terminal specifically includes: Step S601: Based on the preliminarily determined area where the terminal is located, set the position points with the smallest signal feature distance as the starting points, and calculate the relative motion trajectory set in combination with the terminal sensor data; Step S602: Based on the relative motion trajectory set, construct a set of geomagnetic sequences to be matched ; Step S603: Calculate the magnetic field feature distance between the sample geomagnetic sequence and each geomagnetic sequence in the set of geomagnetic sequences to be matched; Further, the magnetic field distance is calculated by the following formula:

[0040] In the formula, represents the pseudorange difference sample corresponding to the coordinate point; is a natural number representing the number of pseudorange difference samples; represents the coordinate point corresponding to the geomagnetic sequence; is a natural number representing the number of geomagnetic sequence coordinate points.

[0041] Step S604: Select the magnetic field feature distance The smallest sample sequence coordinates are used as the terminal trajectory, and then the current position of the terminal is determined.

[0042] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An indoor positioning system based on passive in-building distribution, characterized in that: The system includes a satellite receiving antenna, a single-frequency satellite signal processing unit, a time delay configuration unit, a base station signal source, a combiner, a passive in-building distribution system, cloud services, and a positioning terminal, where: The satellite receiving antenna is installed in an outdoor open area for receiving satellite signals and transmitting the received satellite signals to the single-frequency satellite signal processing unit; The single-frequency satellite signal processing unit is used to amplify and filter the satellite signals received by the satellite receiving antenna, and then retain the satellite signals in a specific frequency band; The time delay configuration unit is used to adjust the time delay of the satellite signals. By configuring and introducing accurate time delay amounts, the range of satellite signal difference eigenvalues between different branch-level regions does not overlap and has distinguishability; The base station signal source is used to provide a signal source in the communication network; The combiner is a specific device located between the base station signal source and the passive in-building distribution system, which is used to combine the downlink signals of the base station signal source and output them to the antenna feeder equipment of the passive in-building distribution system. At the same time, in the reverse direction, it splits the uplink signals from the antenna feeder equipment and outputs them to each system signal source; The passive in-building distribution system usually uses a remote radio unit or a repeater as the signal source, splits and distributes the signals through passive devices, and transmits them to indoor antennas using coaxial cables. The passive devices do not require external power supply; The cloud services are deployed on cloud servers and include an ephemeris information service unit and a differential information service unit; The positioning terminal has a positioning function and integrates one or more of a GNSS signal receiving module, a geomagnetic sensor, and an inertial sensor.

2. An indoor positioning system based on passive in-building distribution according to claim 1, characterized in that: The passive devices include one or more of a power splitter, a coupler, and a combiner; In the cloud services, the ephemeris information service unit provides ephemeris information data download services for the positioning terminal, and the differential information service unit provides real-time differential information for the positioning terminal, where: The ephemeris information is information describing the satellite motion orbit, including satellite orbit parameters relative to a certain reference epoch and necessary orbit perturbation correction term parameters; The differential information is collected by one or more reference stations with known accurate positions and includes pseudorange differential correction amounts and carrier phase differential correction amount data.

3. An indoor positioning method based on passive in-building distribution, which is applied to the indoor positioning system based on passive in-building distribution according to any one of claims 1 or 2, characterized in that, The positioning method includes: Based on two different feeder point positions, two outdoor satellite receiving antennas are used to receive satellite signals. The received satellite signals are amplified and filtered by the satellite signal processing unit, and the satellite signals in a specific frequency band are retained. Feeder point 1 retains satellite signal of frequency 1, and feeder point 2 retains satellite signal of frequency 2; Feed the satellite signal with frequency 1 and the base station signal source into the in-building distributed antenna system through a combiner as the signal of path A, and record the lengths of each branch of the signal of path A as ; Feed the satellite signal with frequency 2 into the indoor distributed antenna system as the B-path signal, and calculate the lengths of each branch of the B-path signal. And set delay configuration units in different branches. Based on the A-path signal and the B-path signal within the positioning area, collect the pseudorange difference between the A-path signal and the B-path signal as the coarse-grained fingerprint for positioning area matching, and collect the geomagnetic sequence within the positioning area as the fine-grained fingerprint for position matching; Based on the collected coarse-grained fingerprint for positioning area matching, match the coarse-grained fingerprints in the sample library to preliminarily determine the area where the terminal is located; Based on the terminal sensor data, match the fine-grained fingerprints in the sample library to further determine the location of the terminal.

4. An indoor positioning method based on passive indoor distribution according to claim 3, characterized in that: The delay configuration unit is set in different branches, and its purpose is to make the range of satellite signal difference eigenvalues between regions at the same branch level non-overlapping and distinguishable.

5. The indoor positioning method based on passive in-building distribution according to claim 3, wherein The delay configuration unit is set in different branches, and the delay configuration should satisfy: In the formula: represents a branch; is a natural number representing the number of branches; represents the speed of light; represents the transmission speed coefficient of electromagnetic waves in the in-building distribution feeder; represents the delay of the th branch; delay of the th branch; represents the delay difference between adjacent branches.

6. An indoor positioning method based on passive indoor distribution according to claim 3, characterized in that: Based on the signal of path A and the signal of path B in the positioning area, collect the pseudorange difference between the signal of path A and the signal of path B, and the calculation expression of the pseudorange difference is: In the formula, represents the pseudo-range difference between the signal of path A and the signal of path B at the position of the floor horizontal coordinate; are respectively the corrected pseudo-range values of the satellite signal of path A and the satellite signal of path B at this position; are respectively the original pseudo-range values of the satellite signal of path A and the satellite signal of path B at this position; and are respectively the pseudo-range correction amounts of the satellite signal of path A and the satellite signal of path B based on the reference station; is the pseudo-range correction amount caused during the transmission time of the satellite signal of path A from the outdoor receiving antenna to the output port of the combiner, which can be obtained through measurement; is the pseudo-range correction amount caused during the transmission time of the satellite signal of path B from the outdoor receiving antenna to the output port of the single-frequency satellite signal processing unit, which can be obtained through measurement; The expression of the geomagnetic sequence in the positioning area is: In the formula, is the floor horizontal coordinate and is the modulus value of the magnetic field signal sample value at the position, that is, the magnetic field modulus value.

7. The indoor positioning method based on passive in-building distribution according to claim 3, wherein, Based on the coarse-grained fingerprints matched in the collected positioning area, match the coarse-grained fingerprints in the sample library, specifically including: Based on the pseudorange difference between the signal of path A and the signal of path B at each coordinate point in the positioning area and the pseudorange difference in the sample library, calculate the signal feature distance to obtain a set of signal feature distances; Select the smallest m coordinate set of pseudorange difference sample values in the signal feature distance set to preliminarily determine the area where the terminal is located.

8. The indoor positioning method based on passive indoor distribution according to claim 7, characterized in that, The calculation expression of the signal feature distance is: In the formula, represents the pseudorange difference sample of the corresponding coordinate point; is a natural number representing the number of pseudorange difference samples.

9. The indoor positioning method based on passive in-building distribution according to claim 3, wherein, Based on the terminal sensor data, match the fine-grained fingerprints in the sample library to further determine the location of the terminal, specifically including: Based on the preliminary determination of the area where the terminal is located, the position point with the smallest signal feature distance will be selected as the starting point, and the relative motion trajectory set will be calculated in combination with the terminal sensor data ; ; Construct a set of geomagnetic sequences to be matched based on the set of relative motion trajectories ; For the sample geomagnetic sequence Calculate the magnetic field feature distance with each geomagnetic sequence in the geomagnetic sequence set to be matched; Select the magnetic field characteristic distance Take the coordinates of the sample sequence with the smallest value as the terminal trajectory, and then determine the current position of the terminal.

10. An indoor positioning method based on passive indoor distribution according to claim 9, characterized in that: The terminal sensor data includes one or more of acceleration, angular velocity and magnetic field data; The expression of the magnetic field distance is: In the formula, represents the pseudorange difference sample of the corresponding coordinate point; is a natural number representing the number of pseudorange difference samples; represents the coordinate point corresponding to the geomagnetic sequence; is a natural number representing the number of geomagnetic sequence coordinate points.

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