An Indoor Wireless Positioning Method and System Based on High-Gain Backscatter Nodes

Abstract

The present invention belongs to the technical field of indoor positioning, and specifically provides an indoor wireless positioning method and system based on a high-gain backscatter node. The method includes the following steps: S1, modeling a tunnel diode, and designing a microstrip tuning circuit and a metal resonator cavity to ensure accurate circuit impedance, obtaining a backscatter node for bouncing wireless signals to change the multipath propagation of wireless signals; S2, attaching the backscatter node to a position where the sky is visible around a wireless device, bouncing the wireless signal to change the multipath propagation characteristics of the wireless signal, so as to achieve signal reception of the indoor wireless device and complete indoor positioning. This solution designs a backscatter node with a small structure volume, low power consumption and low price; it can cover the frequency bands commonly used by satellite positioning signals through simple fine adjustment of the circuit; the backscatter node is used to bounce wireless signals to change the multipath propagation characteristics of wireless signals, and finally helps the wireless device to perform indoor positioning.

Description

Technical Field

[0001] The present invention relates to the technical field of indoor positioning, and more specifically, to an indoor wireless positioning method and system based on high-gain backscatter nodes. Background Art

[0002] The Global Navigation Satellite System (GNSS) has become an indispensable tool for many emerging location-based services, such as navigation, ride-hailing, augmented reality (AR), etc. Satellite positioning technology has the following characteristics: (1) It uses the global coordinate system (ECEF) and does not rely on local coordinates for positioning; (2) It operates in a dedicated licensed spectrum and is less susceptible to interference compared to other technologies in the ISM frequency band; (3) Satellite positioning technology has been deployed and optimized in hundreds of millions of devices, and its applicability has been widely verified. However, the current satellite positioning technology is limited by problems such as few visible satellites indoors, lack of direct paths, and large propagation losses in buildings, and cannot be used indoors. In an indoor environment, the GNSS satellite signals received by wireless devices are weak, the number of satellite signals that can be received is small, and the location information of wireless devices is unknown. When GNSS satellite signals reach the ground, their energy is already very weak (-130 dBm), and a certain gain (>20 dB) of the backscatter node is required to ensure indoor coverage. However, existing backscatter nodes cannot meet both of the above requirements at the same time. For example, in the existing technology 1 (Ambuj Varshney, Andreas Soleiman, and Thiemo Voigt. 2019. Tunnelscatter: Low power communication for sensor tags using tunnel diodes. In The 25th Annual International Conference on Mobile Computing and Networking. 1–17): It is mainly designed for 900 MHz communication signals and realizes negative resistance amplification based on the basic circuit principle of tunnel diodes. It uses an FR4 substrate, does not control the circuit impedance, and has a low sensitivity (about -60 dBm). Existing technology 2 (Amato F, Peterson C W, Degnan B P, et al. Tunneling RFID tags for long-range and low-power microwave applications[J]. IEEE Journal of Radio Frequency Identification, 2018, 2(2):93-103): Existing technology 2 is mainly designed for 5.8 GHz communication signals, realizes a sensitivity of about -90 dBm, and does not design a circuit for tuning and precise impedance control.

[0003] To solve the problem of the application of satellite positioning technology indoors and achieve indoor satellite positioning. Existing methods usually achieve indoor GPS satellite signal coverage by adding a high-gain directional antenna at the receiving end or using a relay amplifier. These methods consume a large amount of power and are not conducive to integration into handheld wireless devices with limited volume. Summary of the Invention

[0004] The present invention needs to solve the problem of indoor wireless positioning technology existing in the prior art.

[0005] The present invention provides an indoor wireless positioning method based on a high-gain backscatter node, including the following steps:

[0006] S1, model a tunnel diode, and design a microstrip tuning circuit and a metal resonator to ensure accurate circuit impedance, obtaining a backscatter node for bouncing wireless signals to change the multipath propagation of wireless signals;

[0007] S2, attach the backscatter node to a position where the sky is visible around the wireless device, bounce the wireless signal to change the multipath propagation characteristics of the wireless signal, so as to realize the signal reception of the indoor wireless device and complete indoor positioning.

[0008] Preferably, after S1 and before S2, it further includes: when the backscatter node circuit structure is obtained, seal the backscatter node in a metal shielding box, and use an impedance analyzer to set the tuning microstrip and tuning screws to adjust the parameters of the circuit, where the tuning microstrip is used to achieve a coarse tuning of 1 to 5 ohms of the frequency, and the tuning screw is used to achieve a fine tuning of 0.004 to 0.2 ohms of the frequency.

[0009] Preferably, S1 specifically includes:

[0010] S11, select a tunnel diode MBD1057 and construct a device model for its volt-ampere characteristics;

[0011] S12, when designing the circuit structure at the design frequency point, make the equivalent impedance of the backscatter circuit containing the tunnel diode MBD1057 be -50 ohm;

[0012] S13, design the circuit bias voltage to reduce the noise figure NF.

[0013] Preferably, after S2, it includes:

[0014] S3, after the wireless device eliminates the noise of the signal-to-noise ratio of the signal, according to the strength characteristics of the signal-to-noise ratio of the signal, separate the original measurement information of the signal corresponding to the bounce path of the backscatter node and the original measurement information of the signal that has not bounced off the backscatter node;

[0015] After the wireless device obtains the ephemeris data of the satellite from the network at S4, it calculates the actual position of the satellite corresponding to the received satellite signal, and then performs virtual mapping on the satellite bounced by the backscatter node to obtain a virtual satellite;

[0016] At S5, the wireless device fuses the signal measurement data of the virtual satellite and the actual satellite, and finally calculates the position of the wireless device, thereby determining the movement trajectory.

[0017] Preferably, S2 specifically includes: The GNSS satellite transmits a wireless positioning signal, and the wireless device receives the signal indoors. When the backscatter node bounces the signal, the signal received by the wireless device is the sum of the signal directly transmitted by the GNSS satellite and the signal bounced by the backscatter node;

[0018] When the backscatter node does not bounce the signal, the signal received by the wireless device is the signal directly transmitted by the GNSS satellite; the wireless device returns the original measurement information according to the received signal.

[0019] Preferably, S2 specifically includes:

[0020] S21, using moving averages with different window lengths to filter the signal strength change to obtain the carrier-to-noise ratio of the stable GNSS satellite signal, so as to separate the signals from two different paths;

[0021] S22, performing virtual mapping on the satellite corresponding to the signal from the bounce path;

[0022] S23, the wireless device first calculates the pseudorange between each GNSS satellite and the wireless device, and uses the phase of the carrier to smooth the pseudorange to improve the ranging accuracy;

[0023] S24, performing iteration on the position according to the iterative weighted least squares algorithm in the classical navigation PVT algorithm;

[0024] S25, after the iterative operation until the position converges to the preset range, substitute it into the following formula to obtain the final position:

[0025] L c = L0 + δL

[0026] where L c represents the actual position of the receiving device, L0 represents the initial position of the iteration, is the position of the backscatter node, and δL is the position convergence vector obtained through iteration.

[0027] The present invention also provides a system for implementing the indoor wireless positioning method based on a high-gain backscatter node, including:

[0028] A backscattering node establishment module, which is used to model a tunnel diode, design a microstrip tuning circuit and a metal resonator to ensure accurate circuit impedance, and obtain a backscattering node for bouncing wireless signals to change the multipath propagation of wireless signals;

[0029] A wireless positioning module, which is used to attach the backscattering node to the position of the visible sky around the wireless device, bounce the wireless signal to change the multipath propagation characteristics of the wireless signal, so as to realize the signal reception of the indoor wireless device and complete indoor positioning.

[0030] The present invention also provides an electronic device, including a memory and a processor. When the processor executes a computer management program stored in the memory, it implements the steps of the indoor wireless positioning method based on a high-gain backscattering node.

[0031] The present invention also provides a computer-readable storage medium, on which a computer management program is stored. When the computer management program is executed by a processor, it implements the steps of the indoor wireless positioning method based on a high-gain backscattering node.

[0032] Beneficial effects: An indoor wireless positioning method and system based on a high-gain backscattering node provided by the present invention. The method includes the following steps: S1, modeling a tunnel diode, designing a microstrip tuning circuit and a metal resonator to ensure accurate circuit impedance, and obtaining a backscattering node for bouncing wireless signals to change the multipath propagation of wireless signals; S2, attaching the backscattering node to the position of the visible sky around the wireless device, bouncing the wireless signal to change the multipath propagation characteristics of the wireless signal, so as to realize the signal reception of the indoor wireless device and complete indoor positioning. This solution is designed for GNSS signals and can cover the commonly used frequency bands of satellite positioning signals (GPS L1, L2, L5 frequency bands, Beidou B1, B2, B3, Galileo E1, E2, etc.) through fine adjustment of a simple circuit. A precision tuning circuit is designed, including a tuning microstrip and a tuning screw connected to a metal shielding box, which can achieve precise impedance control and a sensitivity of -130 dBm.

[0033] This solution designs a backscattering node with a small structure volume, low power consumption and low price. The backscattering node includes a backscattering signal controller and a backscattering signal transmitting circuit; the backscattering node is attached to the position of the visible sky around the wireless device, and the wireless device can be any device that can receive GNSS signals, such as a mobile phone, etc.; the backscattering node is used to bounce wireless signals to change the multipath propagation characteristics of wireless signals, and finally helps the wireless device to position indoors. Description of the Drawings

[0034] Figure 1Schematic diagram of an indoor wireless positioning method based on a high-gain backscatter node provided by the present invention;

[0035] Figure 2 Schematic diagram of the hardware structure of a possible electronic device provided by the present invention;

[0036] Figure 3 Schematic diagram of the hardware structure of a possible computer-readable storage medium provided by the present invention;

[0037] Figure 4 Schematic diagram of the backscatter node circuit provided by the present invention;

[0038] Figure 5 Signal feature diagram after reflection of the backscatter node provided by the present invention;

[0039] Figure 6 Schematic diagram of the virtual satellite equivalent method provided by the present invention;

[0040] Figure 7 Schematic diagram of continuous positioning in a moving situation provided by the present invention;

[0041] Figure 8 Schematic diagram of the signal separation process provided by the present invention;

[0042] Figure 9 Flowchart of calculating the position of the virtual satellite provided by the present invention;

[0043] Figure 10 Schematic diagram of position solution provided by the present invention. Specific embodiments

[0044] The following combines the drawings and embodiments to further describe in detail the specific embodiments of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0045] As Figure 1As shown in the figure, an indoor wireless positioning method and system based on a high-gain backscattering node are provided in an embodiment of the present invention. The method includes the following steps: S1, modeling a tunnel diode, and designing a microstrip tuning circuit and a metal resonator to ensure accurate circuit impedance, so as to obtain a backscattering node for bouncing wireless signals to change the multipath propagation of wireless signals; S2, attaching the backscattering node to a position where the visible sky is around a wireless device, bouncing the wireless signal to change the multipath propagation characteristics of the wireless signal, so as to realize the signal reception of the indoor wireless device and complete indoor positioning. This solution is designed for GNSS signals and can cover the commonly used frequency bands of satellite positioning signals (GPS L1, L2, L5 frequency bands, Beidou B1, B2, B3, Galileo E1, E2, etc.) through fine adjustment of a simple circuit. A precision tuning circuit is designed, including a tuning microstrip and a tuning screw connected to a metal shielding box, which can achieve precise impedance control and a sensitivity of -130 dBm.

[0046] This solution has the following characteristics:

[0047] (1) This high-gain and high-sensitivity design is based on the circuit design and manufacturing method of a backscattering node based on a tunnel diode;

[0048] (2) This solution is a deployment method for deploying backscattering nodes for wireless devices that need to be positioned indoors;

[0049] (3) The wireless device receives the satellite signals of the Global Navigation Satellite System (GNSS) reflected by the backscattering node and the direct GNSS satellite signals;

[0050] (4) Separate the carrier-to-noise ratio of the GNSS signal to obtain the backscattering node bounce signal and the direct GNSS satellite signal; Equivalent the reflected satellite signal to a signal from a virtual satellite, and fuse the GNSS satellite ephemeris and the backscattering node reference position information to locate the position of the indoor wireless device.

[0051] In the case where the number of visible GNSS satellites indoors is small and the GNSS satellite signals are weak, the GNSS satellite signals are reflected into the indoor by the designed and manufactured high-sensitivity and high-gain backscattering nodes. By controlling the backscattering signal transmission circuit to switch between bouncing GNSS signals and absorbing GNSS signals, amplitude change characteristics are added to the indoor GPS signals. The indoor wireless device receives signals with such characteristics, separates the satellite signals in the direct path and the reflected path, and combines virtual satellite equivalence and position solution algorithms to estimate the position of the wireless signal, so as to achieve accurate positioning based on satellite signals indoors.

[0052] Design a backscatter node with a small size, low power consumption, and low cost. The backscatter node includes a backscatter signal controller and a backscatter signal transmitting circuit. Attach the backscatter node to a position where the sky is visible around the wireless device. The wireless device can be any device capable of receiving GNSS signals, such as a mobile phone. The backscatter node is used to bounce wireless signals to change the multipath propagation characteristics of the wireless signals, ultimately helping the wireless device to perform indoor positioning.

[0053] In addition, to design and manufacture such a high-sensitivity and high-gain backscatter node, precise modeling of the tunnel diode of model MBD1057 was carried out, and a microstrip tuning circuit and a metal resonant cavity were innovatively designed to ensure precise circuit impedance, reducing the process error during manufacturing and the influence of external electromagnetic noise on the circuit impedance.

[0054] The circuit diagram of the backscatter node is as Figure 4 shown, including a radio frequency microstrip circuit and a baseband processing circuit. The wireless signal enters the radio frequency microstrip circuit for processing. Specifically, on the one hand, the wireless signal sequentially passes through a coupling capacitor, a tuning microstrip, a tunnel diode and then grounds; on the other hand, after passing through the coupling capacitor, the wireless signal passes through a microstrip T bias, a microstrip low-pass filter, and a tuning contact is set in front of the microstrip T bias to perform tuning corresponding to the tuning screw. The baseband processing circuit mainly provides a low-frequency square wave signal to control the reflection of the satellite signal by the radio frequency microstrip circuit. The high level (about 140 mV) of the square wave signal controls the radio frequency microstrip circuit to reflect and amplify the satellite signal. At this time, the mobile phone can receive the reflected satellite signal with significantly increased energy. The low level (about 0 mV) of the square wave signal does not reflect the satellite signal. Each node can modulate its own ID on the satellite signal in this way, and the mobile phone can judge whether the signal is reflected by the backscatter node and which node reflects it according to the intensity of the satellite signal.

[0055] In a specific implementation scenario, the principle of the specific indoor wireless positioning method is as follows:

[0056] First, select the tunnel diode and construct a device model for its volt-ampere characteristics. To achieve the above-mentioned high-gain backscattering effect, first according to the reflection coefficient formula:

[0057]

[0058] It can be seen that when the antenna impedance Z A is known, the amplitude and phase of the reflected signal depend on the internal circuit impedance Z L , and when Z L approaches -Z AA larger gain is obtained at that time. Therefore, a precise impedance matching circuit is designed. At the designed frequency point, the equivalent impedance of the backscattering circuit containing the tunnel diode is made close to -50 ohm through the circuit structure.

[0059] At the same time, the receiving sensitivity of the communication system is analyzed. The formula for the receiving sensitivity of the communication system is as follows:

[0060] P sensitivity = 10log(kTB) + NF + SNR min -G p

[0061] Where k is the thermodynamic constant, T is the temperature, B is the bandwidth, and NF is the noise figure. Since these constants cannot be changed during the system design and use, a smaller noise figure means higher receiving sensitivity. The noise figure NF of the system is minimized through the design of the circuit bias voltage.

[0062]

[0063] In the tunnel diode circuit, the expression formula for the noise figure is as above, where K a is the noise constant, which is approximately 1.2 - 1.4 for germanium-based tunnel diodes, R j is the selected negative resistance, which can be calculated according to the voltage-current characteristic curve, R s is the substrate resistance of the tunnel diode, f is the operating frequency, that is, f r0 is the cut-off frequency. Through modeling and calculation, its minimum value in the negative resistance region can be obtained.

[0064] After the above design is completed, due to the limitations of the circuit manufacturing and processing accuracy, and the tolerance of the dielectric constant of the circuit board, it is impossible to directly manufacture a device that meets the requirements. Therefore, a tuning microstrip is designed in the circuit structure. After the circuit is manufactured, the circuit parameters can be adjusted according to the tuning microstrip and tuning screws in combination with a precise impedance analyzer. The tuning microstrip can achieve coarse tuning of the frequency (1 - 5 ohms), while the tuning screws can achieve fine tuning (0.004 - 0.2 ohms). Since the circuit sensitivity is relatively high, a metal shielding box is also designed and manufactured to shield against external electromagnetic interference.

[0065] After the hardware design and production of the node are completed, the backscattering node is then attached to a position where the sky is visible around the wireless device. The wireless device can be any device that can receive GNSS signals, such as a mobile phone, etc.; the backscattering node is used to bounce wireless signals to change the multipath propagation characteristics of the wireless signals, and ultimately helps the wireless device to perform indoor positioning.

[0066] Preferably, the backscatter node is used to bounce wireless signals to change the multipath propagation of wireless signals, specifically including the following four steps:

[0067] (1) GNSS satellites transmit wireless signals. When the wireless signals are blocked, indoor wireless devices cannot receive the blocked signals, but can receive the unblocked direct-path GNSS satellite signals and the GNSS satellite signals bounced by the backscatter node, and return the original measurement information of the signals.

[0068] (2) As shown in Figure 5 , after the wireless device eliminates the noise of the signal-to-noise ratio of the signal, it separates the original measurement information of the signal corresponding to the backscatter node bounce path and the original measurement information of the signal that has not been bounced by the backscatter node according to the strength characteristics of the signal-to-noise ratio of the signal.

[0069] (3) As shown in Figure 6 , after the wireless device obtains the ephemeris data of the satellite from the network, it can calculate the actual position of the satellite corresponding to the received satellite signal, and then perform virtual mapping on the satellite bounced by the backscatter node to obtain a virtual satellite.

[0070] (4) As shown in Figure 7 , the wireless device fuses the signal measurement data of the virtual satellite and the actual satellite, and finally calculates the position of the wireless device, and then determines the movement trajectory.

[0071] Specifically, GNSS satellites transmit wireless positioning signals, and wireless devices receive signals indoors. When the backscatter node bounces signals, the signals received by the wireless device are the sum of the signals directly transmitted by GNSS satellites and the signals bounced by the backscatter node; when the backscatter node does not bounce signals, the signals received by the wireless device are the signals directly transmitted by GNSS satellites; the wireless device returns the original measurement information according to the received signals.

[0072] (5) As shown in Figure 8 , the wireless device first needs to separate the signals bounced by the backscatter node. The present invention uses the characteristics that the backscatter node can provide considerable gain for weak signals and the GNSS satellite signal receiving module can calculate the strength of the GNSS signal at the receiving end to detect the signals bounced by the backscatter node.

[0073] The backscatter node has the characteristics of high sensitivity and high gain, and can reflect and amplify weak GNSS satellite signals on the ground. When the backscatter node bounces the signal, the wireless device will receive the sum of the GNSS satellite signal and the bounced signal of the backscatter node. Compared with when the backscatter node does not bounce the signal, the wireless device can only receive the direct GNSS satellite signal, and the amplified sum signal strength is stronger than the direct path signal. In the original measurement information of the GNSS satellite signal, the carrier-to-noise ratio, that is, the carrier-to-noise ratio, can intuitively reflect the strength of the signal.

[0074] In the process of GNSS satellite signals being sent from space to reaching ground receiving equipment, the signals undergo a certain degree of attenuation due to the influence of the atmosphere. The satellite moves very quickly for a period of time, which is reflected as a change in angle for ground observation equipment and as a change in propagation path for the signal. The attenuation changes at this time are slow over time, which is called "slow fading".

[0075] When the GNSS satellite signal reaches the ground, due to the complex environment on the ground, a complex multipath effect will occur. As the satellite signal angle changes, the signal propagation path on the ground will change rapidly, resulting in rapid changes in signal strength, which is called "fast fading."

[0076] Since the characteristics of the rebound signal of the backscattering node are mainly reflected in the signal strength, the effects of "slow fading" and "fast fading" must be filtered out respectively, and the moving averages of different window lengths are used for processing:

[0077]

[0078] Where n represents the moving window length, It represents the moving average of the received signal energy, which can be expressed by the satellite signal carrier-to-noise ratio. For slow fading, a longer moving window is used, and for fast fading, a shorter moving window is used. M represents the measured pseudorange at the Mth moment. Similarly, P M-(n-1) is the measurement value at the previous n moments. By smoothing the measurement value, a stable carrier-to-noise ratio of the GNSS satellite signal can be obtained, making it easy to separate signals from two different paths.

[0079] like Figure 9 As shown in the figure, the virtual satellite mapping process proposed by the present invention can enrich the number of positioning satellites and improve positioning accuracy. Through the network, the orbit information of all GNSS satellites in the time period can be obtained from the server, and the position of the corresponding satellite in the sky can be calculated according to the number of the received satellite. After separating the signals with different paths, the signals from the rebound path are virtually mapped to the corresponding satellites:

[0080]

[0081]

[0082] where P v P r P n represent the coordinate positions of the virtual mapping satellite, the real satellite, and the backscatter node respectively. The coordinates are uniformly in the Earth-Centered Earth-Fixed coordinate system. is the unit direction vector of the backscatter node, and q represents the quaternion of rotation.

[0083] As Figure 10 shown, the wireless device first calculates the pseudorange between each GNSS satellite and the wireless device, and uses the phase of the carrier wave to smooth the pseudorange to improve the ranging accuracy:

[0084]

[0085] where ρ s represents the smoothed pseudorange, (t - 1) represents the parameter of the previous moment, t represents the parameter of the current moment, φ represents the phase of the carrier wave, λ represents the wavelength, and M represents the length of the smoothing window.

[0086] Then, according to the iterative weighted least squares (wls) algorithm in the classical navigation PVT algorithm:

[0087] δρ (k) = ρ c (k) - ρ0 (k)

[0088] ≈ -I (k) δL + cδt b + ε ρ

[0089] where k represents the k-th satellite received, ρ c , ρ0 represent the actual pseudorange and the observed pseudorange from the satellite to the receiving device respectively, L represents the coordinates of the receiving device, t b represents the clock difference between the satellite and the receiving device, and ε ρ represents the error term of the pseudorange.

[0090] Substitute the backscattered signal and the direct signal of the backscatter node into the calculation to obtain:

[0091]

[0092] where W represents the weight matrix, which is determined by the quality of the received satellite signal, and G is extended from the unit direction vector between the satellite and the receiving device. After several iterations of wls operation, until the position converges to a certain range, substitute it into the following formula to obtain the final position:

[0093] L c = L0 + δL

[0094] where L c represents the actual position of the receiving device, L0 represents the initial position of the iteration, which is the position of the backscatter node, and δL is the position convergence vector obtained through iteration. Through the present invention, there is no need to modify the hardware or driver of the wireless device, and precise positioning can be achieved even in an environment where the number of visible satellites indoors is difficult to meet the requirements of traditional positioning algorithms.

[0095] Please refer to Figure 2 which is a schematic diagram of an embodiment of an electronic device provided by an embodiment of the present invention. As Figure 2 shown, an embodiment of the present invention provides an electronic device, including a memory 1310, a processor 1320, and a computer program 1311 stored in the memory 1310 and executable on the processor 1320. When the processor 1320 executes the computer program 1311, the following steps are implemented:

[0096] S1, model a tunnel diode, and design a microstrip tuning circuit and a metal resonator to ensure precise circuit impedance, so as to obtain a backscatter node for bouncing a wireless signal to change the multipath propagation of the wireless signal;

[0097] S2, attach the backscatter node to a position where the sky is visible around the wireless device, bounce the wireless signal to change the multipath propagation characteristics of the wireless signal, so as to achieve signal reception of the indoor wireless device and complete indoor positioning.

[0098] Please refer to Figure 3 which is a schematic diagram of an embodiment of a computer-readable storage medium provided by the present invention. As Figure 3 shown, this embodiment provides a computer-readable storage medium 1400, on which a computer program 1411 is stored. When the computer program 1411 is executed by a processor, the following steps are implemented:

[0099] S1, model a tunnel diode, and design a microstrip tuning circuit and a metal resonator to ensure precise circuit impedance, so as to obtain a backscatter node for bouncing a wireless signal to change the multipath propagation of the wireless signal;

[0100] S2, attach the backscatter node to a position where the sky is visible around the wireless device, bounce the wireless signal to change the multipath propagation characteristics of the wireless signal, so as to achieve signal reception of the indoor wireless device and complete indoor positioning.

[0101] It should be noted that in the above embodiments, the descriptions of the various embodiments have their own emphases. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0102] Those skilled in the art should understand that the embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0103] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded computer, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in Figure 1 one or more of the processes Figure 1 or a plurality of processes and / or blocks

[0104] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions specified in Figure 1 one or more of the processes Figure 1 or a plurality of processes and / or blocks

[0105] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one or more of the processes Figure 1 or a plurality of processes and / or blocks

[0106] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn the basic inventive concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention.

[0107] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. An indoor wireless positioning method based on high-gain backscatter nodes, characterized in that, Including the following steps: S1. Model the tunnel diode, and design a microstrip tuning circuit and a metal resonator to ensure accurate circuit impedance, so as to obtain a backscattering node for bouncing wireless signals to change the multipath propagation of wireless signals; The backscattering node is used to reflect GNSS satellite signals into the indoor area when the number of visible GNSS satellites in the indoor area is small and the GNSS satellite signals are weak; S2. Attach the backscattering node to a position where the sky is visible around the wireless device, bounce the wireless signal to change the multipath propagation characteristics of the wireless signal, so as to realize the signal reception of the indoor wireless device; S3. After the wireless device eliminates the noise of the signal-to-noise ratio of the signal, according to the strength characteristics of the signal-to-noise ratio of the signal, separate the original measurement information of the signal corresponding to the backscattering node bounce path and the original measurement information of the signal that has not been bounced by the backscattering node; S4. After the wireless device obtains the ephemeris data of the satellite from the network, calculate the actual position of the satellite corresponding to the received satellite signal, and then perform virtual mapping on the satellite bounced by the backscattering node to obtain a virtual satellite; S5. The wireless device fuses the signal measurement data of the virtual satellite and the actual satellite, and finally calculates the position of the wireless device, and then determines the movement trajectory.

2. The indoor wireless positioning method based on a high-gain backscatter node according to claim 1, wherein After S1 and before S2, it further includes: when the circuit structure of the backscattering node is obtained, seal the backscattering node in a metal shielding box, and use an impedance analyzer to set the tuning microstrip and tuning screws to adjust the parameters of the circuit, where the tuning microstrip is used to achieve a coarse tuning of 1 to 5 ohms of the frequency, and the tuning screw is used to achieve a fine tuning of 0.004 to 0.2 ohms of the frequency.

3. The indoor wireless positioning method based on a high-gain backscatter node according to claim 1, wherein The specific content of S1 includes: S11. Select the tunnel diode MBD1057 and construct a device model according to the volt-ampere characteristics; S12. When designing the circuit structure at the design frequency point, make the equivalent impedance of the backscattering circuit containing the tunnel diode MBD1057 be -50 ohm; S13. Design the circuit bias voltage to suppress the noise figure NF.

4. The indoor wireless positioning method based on a high-gain backscatter node according to claim 1, characterized in that, The specific content of S2 includes: The GNSS satellite transmits a wireless positioning signal, and the wireless device receives the signal indoors. When the backscattering node bounces the signal, the signal received by the wireless device is the sum of the signal directly transmitted by the GNSS satellite and the signal bounced by the backscattering node; When the backscattering node does not bounce the signal, the signal received by the wireless device is the signal directly transmitted by the GNSS satellite; the wireless device returns the original measurement information according to the received signal.

5. The indoor wireless positioning method based on a high-gain backscatter node according to claim 1, wherein The method further includes: Use moving averages with different window lengths to filter the signal strength change to obtain a stable signal-to-noise ratio of the GNSS satellite signal, so as to separate the signals from two different paths; Perform virtual mapping on the satellite corresponding to the signal from the bounce path; The wireless device first calculates the pseudorange between each GNSS satellite and the wireless device, and uses the phase of the carrier to smooth the pseudorange to improve the ranging accuracy; Iterate the position according to the iterative weighted least squares algorithm in the classical navigation PVT algorithm; After the iterative operation converges to a preset range, substitute it into the following formula to obtain the final position: ； wherein represents the actual position of the receiving device represents the initial position of the iteration, which is the position of the backscattering node is the position convergence vector obtained through iteration 6. A system for implementing the indoor wireless positioning method based on a high-gain backscatter node according to any one of claims 1-5, characterized in that, Including: A backscattering node establishment module, which is used to model a tunnel diode, design a microstrip tuning circuit and a metal resonator to ensure accurate circuit impedance, and obtain a backscattering node for bouncing a wireless signal to change the multipath propagation of the wireless signal; A wireless positioning module, which is used to attach the backscattering node to a position in the visible sky around a wireless device, bounce the wireless signal to change the multipath propagation characteristics of the wireless signal, so as to realize the signal reception of the indoor wireless device and complete indoor positioning.

7. An electronic device, characterized in that, It includes a memory and a processor, and the processor is used to implement the steps of the indoor wireless positioning method based on a high-gain backscattering node according to any one of claims 1-5 when executing a computer management program stored in the memory.

8. A computer-readable storage medium, characterized in that, A computer management program is stored thereon, and when the computer management program is executed by a processor, the steps of the indoor wireless positioning method based on a high-gain backscattering node according to any one of claims 1-5 are implemented.

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