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CN114779298B - Indoor satellite positioning method and system with multipath error correction - Google Patents

Indoor satellite positioning method and system with multipath error correction Download PDF

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Publication number
CN114779298B
CN114779298B CN202210305211.0A CN202210305211A CN114779298B CN 114779298 B CN114779298 B CN 114779298B CN 202210305211 A CN202210305211 A CN 202210305211A CN 114779298 B CN114779298 B CN 114779298B
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signal
satellite
wireless device
node
indoor
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CN114779298A (en
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王巍
董慧鑫
谢怡荣
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Huazhong University of Science and Technology
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Huazhong University of Science and Technology
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/42—Determining position
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)

Abstract

本发明属于室内卫星定位技术领域，具体提供了一种多径误差修正的室内卫星定位方法及系统，其中方法包括GNSS卫星发射无线信号，当信号有遮挡时，室内的无线设备无法收到被遮挡的信号，通过收到无遮挡的直射路径GNSS卫星信号和背向散射节点反弹的GNSS卫星信号，并返回信号的原始测量信息；无线设备从网络获取到卫星的星历数据后，可计算出收到的卫星信号对应卫星的实际位置，获取背向散射节点的已知位置，结合接收到的卫星信号的原始测量信息，根据背向散射节点的反射状态建立模型，列出观测方程，求解无线设备的位置。该方案功耗低、体积小、价格便宜的背向散射节点附加在无线设备周围可见天空的位置，无线设备可以是任意可以进行GNSS信号接收的设备。

The present invention belongs to the technical field of indoor satellite positioning, and specifically provides an indoor satellite positioning method and system with multipath error correction, wherein the method includes GNSS satellite transmitting wireless signals, when the signal is blocked, the indoor wireless device cannot receive the blocked signal, by receiving the unblocked direct path GNSS satellite signal and the GNSS satellite signal bounced by the backscattering node, and returning the original measurement information of the signal; after the wireless device obtains the satellite ephemeris data from the network, it can calculate the actual position of the satellite corresponding to the received satellite signal, obtain the known position of the backscattering node, combine the original measurement information of the received satellite signal, establish a model according to the reflection state of the backscattering node, list the observation equation, and solve the position of the wireless device. The backscattering node of the scheme with low power consumption, small size and low price is attached to the position of the sky visible around the wireless device, and the wireless device can be any device that can receive GNSS signals.

Description

Indoor satellite positioning method and system for multipath error correction
Technical Field
The invention relates to the technical field of indoor satellite positioning, in particular to an indoor satellite positioning method and system for multipath error correction.
Background
Global satellite positioning systems (GNSS) have become an indispensable tool for many emerging location-based services, such as navigation, driving, augmented Reality (AR), etc. The satellite positioning technology has the following characteristics:
(1) Using the global coordinate system (ECEF), independent of local coordinate positioning;
(2) The licensed spectrum which is dedicated for work is not easy to receive interference compared with other technologies of ISM frequency points;
(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 the problems of small number of indoor visible satellites, lack of direct paths, large propagation loss in buildings and the like, and cannot be used indoors. In indoor environment, namely, the GNSS satellite signals which can be received by the wireless equipment are weak, the number of the received satellite signals is small, the position information of the wireless equipment is unknown, and the wireless equipment only needs to use one or more backscattering nodes with low power consumption, small volume and low price to be deployed at the positions of surrounding visible sky for positioning. For example, in a mall or station, a guest may utilize a backscatter node deployed at the edge of a window for indoor positioning. In order to solve the problem of indoor application of satellite positioning technology, indoor satellite positioning is realized. In the prior art methods, such as the published papers Jie Liu,Bodhi Priyantha,Ted Hart,Yuzhe Jin,Woosuk Lee,Vijay Raghunathan,Heitor S Ramos,and Qiang Wang.2015.CO-GPS:Energy efficient GPS sensing with cloud offloading.IEEE Transactions on MobileComputing 15,6(2015),1348–1361 and Shahriar Nirjon,Jie Liu,Gerald DeJean,Bodhi Priyantha,Yuzhe Jin,and Ted Hart.2014.COIN-GPS:indoor localization from direct GPS receiving.In Proceedings ofthe 12th annual international conference on Mobile systems,applications,and services.301–314,, the above prior art generally uses a high gain directional antenna at the receiving end or a relay amplifier to achieve indoor GPS satellite signal coverage, which has large power consumption and is not beneficial to be integrated into a handheld wireless device with limited volume.
It can be seen that there is currently a lack of a low power indoor satellite positioning scheme suitable for handheld wireless devices.
Disclosure of Invention
The invention aims at the technical problem of high indoor satellite positioning power consumption in the prior art.
The invention provides an indoor satellite positioning method for multipath error correction, which comprises the following steps:
S1, a GNSS satellite transmits wireless signals, when the signals are blocked, indoor wireless equipment cannot receive the blocked signals, receives direct path GNSS satellite signals without blocking and GNSS satellite signals rebounded by a backscattering node, and returns original measurement information of the signals;
S2, after the wireless equipment acquires ephemeris data of the satellite from the network, the actual position of the satellite corresponding to the received satellite signal can be calculated, the known position of the back scattering node is acquired, the model is built according to the reflection state of the back scattering node by combining the original measurement information of the received satellite signal, an observation equation is listed, and the position of the wireless equipment is solved.
Preferably, the S2 specifically includes:
when the backscattering node rebounds the signal, the signal received by the wireless device is the sum of the signal of the direct irradiation of the GNSS satellite and the signal rebounded by the backscattering node;
when the backscattering node does not rebound signals, the signals received by the wireless equipment are signals directly irradiated by the GNSS satellites, and the wireless equipment returns original measurement information according to the received signals.
Preferably, after receiving the signal, the wireless device needs to separate the signal rebounded by the back scattering node, specifically, according to the characteristic that the back scattering node can provide considerable gain for the weak signal and the GNSS satellite signal receiving module can calculate the GNSS signal intensity of the receiving end, the signal rebounded by the back scattering node is detected.
Preferably, the step S1 specifically comprises the step of utilizing a back scattering node to perform combined positioning with the received satellites when the number of satellites is insufficient.
Preferably, the step S2 specifically comprises the steps of dividing direct path expansion and indirect path expansion according to whether the wireless equipment and the backscattering node are available or not;
The method comprises the steps that in the first state, a direct path expands, a backscattering node rebounds signals at a time t 1, and wireless equipment can receive signals from a direct path of a satellite and signals from a backscattering node at the same time, namely, the summation of the signals of the direct path of the satellite and the backscattering node is achieved;
In state two, the backscatter node absorbs the signal at time t 2, and the wireless device can only receive the direct path signal from the satellite.
Preferably, the S2 specifically includes:
state one, the actual propagation distance is:
and a second state, wherein the actual propagation distance is as follows:
Wherein H is the height of the wireless device held by the user and is also the vertical height of the back scattering node deployment; the value can be determined with few iterations, The length of the geometric propagation path of the signal received by the wireless device at the time t 1,t2 is respectively, namely the actual propagation distance of the signal; the geometrical distances from the satellite to the backscattering node at time t 1,t2 are respectively recorded as baseline vectors As the direction vector of the satellite to the backscatter node,As a direction vector from the backscatter node to the earth's center,Is an error correction term obtained by searching in the range of 0-2H.
The invention also provides an indoor satellite positioning system for multipath error correction, which is used for realizing the indoor satellite positioning method for multipath error correction, and specifically comprises the following steps:
The original signal measurement module is used for receiving the blocked signal when the GNSS satellite transmits the wireless signal, receiving the direct path GNSS satellite signal without the blocking and the GNSS satellite signal rebounded by the backscattering node, and returning the original measurement information of the signal;
The multipath error correction module is used for calculating the actual position of the satellite corresponding to the received satellite signal after the wireless device acquires the ephemeris data of the satellite from the network, acquiring the known position of the back scattering node, combining the original measurement information of the received satellite signal, building a model according to the reflection state of the back scattering node, listing an observation equation, and solving the position of the wireless device.
The invention also provides an electronic device, which comprises a memory and a processor, wherein the processor is used for executing the steps of the indoor satellite positioning method for realizing multipath error correction when the computer management program stored in the memory.
The present invention also provides a computer-readable storage medium having stored thereon a computer-management-class program which, when executed by a processor, implements the steps of the multipath error correction indoor satellite positioning method.
The indoor satellite positioning method and system for multipath error correction have the beneficial effects that the method comprises the steps that GNSS satellites emit wireless signals, when the signals are blocked, indoor wireless equipment cannot receive the blocked signals, through receiving direct path GNSS satellite signals without blocking and GNSS satellite signals rebounded by a back scattering node, original measurement information of the signals is returned, after the wireless equipment acquires ephemeris data of the satellites from a network, the actual positions of the received satellite signals corresponding to the satellites can be calculated, known positions of the back scattering node are acquired, and by combining the received original measurement information of the satellite signals, a model is built according to the reflection state of the back scattering node, observation equations are listed, and the positions of the wireless equipment are solved. The backscattering nodes with low power consumption, small volume and low price are attached to the positions of visible sky around the wireless equipment, and the wireless equipment can be any wireless equipment capable of receiving GNSS signals, such as a mobile phone and the like; the backscatter nodes are used to bounce the wireless signal to change the multipath propagation characteristics of the wireless signal, ultimately helping the wireless device locate indoors.
Drawings
FIG. 1 is a flow chart of an indoor satellite positioning method with multipath error correction provided by the invention;
Fig. 2 is a schematic hardware structure of one possible electronic device according to the present invention;
FIG. 3 is a schematic diagram of a possible hardware configuration of a computer readable storage medium according to the present invention;
FIG. 4 is a schematic diagram of modeling correction for multipath conditions in a room according to the present invention;
FIG. 5 is a schematic diagram of the present invention when there is a signal occlusion;
FIG. 6 is a schematic diagram illustrating backscattering node bounce provided by the present invention
FIG. 7 is a schematic diagram of two states of multipath error provided by the present invention;
fig. 8 is a schematic diagram of two states at time t 1 and time t 2 provided by the present invention;
FIG. 9 is a schematic diagram of an indoor satellite positioning method for multipath error correction provided by the present invention;
Detailed Description
The following describes in further detail the embodiments of the present invention with reference to the drawings and examples. The following examples are illustrative of the invention and are not intended to limit the scope of the invention.
As shown in FIG. 1, the indoor satellite positioning method for multipath error correction provided by the embodiment of the invention comprises the steps that GNSS satellites transmit wireless signals, when the signals are blocked, indoor wireless equipment cannot receive the blocked signals, through receiving direct path GNSS satellite signals without blocking and GNSS satellite signals rebounded by a back scattering node, original measurement information of the signals is returned, after the wireless equipment acquires ephemeris data of the satellites from a network, the actual positions of the received satellite signals corresponding to the satellites can be calculated, known positions of the back scattering node are acquired, and a model is built according to the reflection state of the back scattering node in combination with the received original measurement information of the satellite signals, an observation equation is listed, and the positions of the wireless equipment are solved. The backscattering nodes with low power consumption, small volume and low price are attached to the positions of visible sky around the wireless equipment, and the wireless equipment can be any wireless equipment capable of receiving GNSS signals, such as a mobile phone and the like; the backscatter nodes are used to bounce the wireless signal to change the multipath propagation characteristics of the wireless signal, ultimately helping the wireless device locate indoors.
The scheme does not need to make any hardware/firmware modification to the wireless device, and is easy to deploy and popularize. The method comprises the steps of deploying a back scattering node in indoor wireless equipment to be located, receiving satellite navigation system (GNSS, global Navigation SATELLITE SYSTEM) satellite signals and direct GNSS satellite signals reflected by the back scattering node by the wireless equipment, separating carrier-to-noise ratios of the GNSS signals to obtain back scattering node rebound signals and direct GNSS satellite signals, measuring accumulated carrier phases of the GNSS satellite signals of a direct path and a reflection path, fusing GNSS satellite ephemeris and back scattering node reference position information, and locating the indoor wireless equipment. According to the invention, under the condition that the number of indoor visible GNSS satellites is small and GNSS satellite signals are weak, the back scattering signal transmitting circuit is controlled to switch between rebounding GNSS signals and absorbing GNSS signals, so that the accurate indoor positioning of the wireless equipment is realized.
The backscattering nodes with low power consumption, small volume and low price are attached to the positions of visible sky around the wireless equipment, and the wireless equipment can be any equipment capable of receiving GNSS signals, such as a mobile phone and the like; the backscatter nodes are used to bounce the wireless signal to change the multipath propagation characteristics of the wireless signal, ultimately helping the wireless device locate indoors.
In a specific implementation scenario, in an indoor environment, that is, in an environment where GNSS satellite signals that can be received by a wireless device are weak, the number of satellite signals that can be received is small, and location information of the wireless device is unknown, the wireless device only needs to use one or more backscattering nodes with low power consumption, small volume and low price to deploy at positions of surrounding visible sky to perform positioning. For example, in a mall or station, a guest may utilize a backscatter node deployed at the edge of a window for indoor positioning.
Based on the scene, one or more backscattering nodes with low power consumption, small volume and low price are added at the position of visible sky around the wireless device, the wireless device can be any device capable of receiving GNSS signals, such as a mobile phone and the like, and the backscattering nodes are used for rebounding the wireless signals to change the multipath propagation characteristics of the wireless signals, so that the indoor positioning of the wireless device is finally assisted.
The invention designs that the back scattering node is attached at the visible sky position around the wireless device and is used for rebounding the wireless signal to change the multipath propagation of the wireless signal, and the embodiment of the invention has the following technologies comprising:
(1) The back scattering auxiliary positioning technology is characterized in that after the ejected satellite signals are distinguished from the satellite signals of the direct path, the real-time position of the satellite is calculated according to ephemeris data of the satellite, and the accumulated observation values of the sampled satellite signals are combined with the known position coordinates of the back scattering nodes to carry out modeling in a short time.
In the conventional positioning model, signal data of at least four satellites are required, and in the positioning model established by the patent, when the number of satellites is insufficient, the backscattering nodes and the received satellites can be utilized for combined positioning, so that the minimum number of satellites participating in positioning is smaller than that of the conventional positioning. For example, in an indoor environment, the mobile phone can only receive signals from the satellites a and B, at this time, the number of satellites is 2 which is less than 4 satellites required by the traditional positioning model, when the backscattering nodes a and B are deployed at the appropriate positions, two satellites and two backscattering nodes are shared, the mobile phone can receive signals directly from the satellites a and B and reflected signals from the backscattering nodes a and B, and the position of the mobile phone can be obtained by combined modeling, so that positioning is completed. As shown in fig. 6.
(2) In the multipath error correction technology, because the indoor environment is complex, the satellite moves relative to the ground, the receiving end wireless device can hardly receive the direct signal of the satellite, but the reflected signal passes through other indoor reflecting surfaces, and meanwhile, a barrier can exist between the back scattering node and the receiving end wireless device, so that the signal amplified and reflected by the back scattering node cannot be directly transmitted to the receiving end wireless device, and thus, positioning errors are brought. The two cases are divided into the expansion of paths by multipath reflection, with and without the backscatter node in the line of sight of the receiving end wireless device.
The specific scheme principle process is as follows:
(1) As shown in fig. 5, a GNSS satellite transmits a wireless signal, when the signal is blocked, the indoor wireless device cannot receive the blocked signal, and can receive the direct path GNSS satellite signal without blocking and the GNSS satellite signal rebounded by the backscatter node, and return the original measurement information of the signal;
(2) As shown in fig. 6, after the wireless device obtains ephemeris data of the satellite from the network, the actual position of the satellite corresponding to the received satellite signal can be calculated, the known position of the back scattering node is obtained, the model is built according to two states of the back scattering node by combining the signal original measurement information of the received satellite signal, an observation equation is listed, and the position of the wireless device is solved;
(3) As shown in fig. 7, the indoor condition of the wireless device is complex, so as to improve the accuracy of indoor positioning and robustness, two common models of indoor multipath errors are provided, and the correction models reduce the errors.
Specifically, the GNSS satellite transmits a wireless positioning signal, the wireless device receives the signal indoors, when the backscattering node rebounds the signal, the signal received by the wireless device is the sum of the direct signal of the GNSS satellite and the signal rebounded by the backscattering node, when the backscattering node does not rebound the signal, the signal received by the wireless device is the direct signal of the GNSS satellite, and the wireless device returns the original measurement information according to the received signal.
As shown in fig. 8, the wireless device first needs to separate the signal that the backscatter node bounces. According to the scheme, the characteristics that the backscattering node can provide considerable gain for weak signals and the GNSS satellite signal receiving module can calculate the GNSS signal intensity of the receiving end are utilized, and the signals bounced by the backscattering node are detected.
The back scattering node has the characteristics of high sensitivity and high gain, and can be used for carrying out reflection amplification on GNSS satellite signals with weak ground. When the backscattering node bounces signals, the wireless device receives the sum of GNSS satellite signals and backscattering node bounces signals, and compared with the situation that the backscattering node does not bounce signals, the wireless device can only receive direct GNSS satellite signals, and the amplified sum signal intensity is stronger than that of direct path signals. In the original measurement information of the GNSS satellite signals, the carrier-to-noise ratio, namely the carrier-to-noise ratio, can intuitively reflect the strength of the signals.
As shown in fig. 8, the system state is divided into two states according to the reflection state of the back scattering node, the back scattering node absorbs signals at time t 2, the wireless device can only receive direct path signals from satellites, the back scattering node rebound signal at time t 1, the wireless device can receive signals from direct paths of satellites and signals from the back scattering node at the same time, namely, the summation of the signals of the two signals.
Signals of GNSS satellites at any moment reach the ground through an atmosphere layer, and electromagnetic waves can be scattered, reflected, diffracted and the like in an ionosphere and a troposphere in the atmosphere layer, so that the signals are delayed for a certain time. In the positioning system of the GNSS receiver, the position is determined by the measurement of the signal propagation path, so the positioning accuracy depends on the accurate measurement of the signal propagation time, while the error brought by the atmosphere is changed along with time and is difficult to accurately measure and estimate, so the distance measurement errors generated by the ionosphere and the troposphere delays are respectively recorded as I and T.
Recording deviceThe length of the geometric propagation path of the signal received by the wireless device at time t 1,t2, i.e. the actual propagation distance of the signal, respectively. To improve positioning accuracy, the phase of the GNSS satellite carrier is measured at the wireless device, denoted Φ, with a distance unit, representing the accumulated wave path of the wireless device after capturing the locked satellite carrier signal, which will generate a whole-cycle ambiguity distance error N due to the periodicity of the carrier signal. The receiving end wireless device measures signal propagation delay, and the generated distance error is recorded as (t (R,t)-t(S,t)) because the clock stability of the local system and the satellite-borne atomic clock performance of the satellite are greatly different and are called clock difference. For two adjacent different states, the time points are:
t1:
t2:
the time interval t 1,t2 is very short, the atmosphere state can be considered unchanged during the time, and the generated atmosphere time delay is consistent; The epsilon Φ represents the error term of the phase measurement, which is the distance error caused by the propagation delay of the signal in the backscattering node, can be measured by an instrument, and the backscattering node is far away from the ground and is far away from the wireless equipment and is smaller than the distance from the satellite, so that the signal of the satellite can be considered to reach the ground in parallel, and the error term of the phase measurement is recorded The geometrical distances from the satellite to the backscattering node at time t 1,t2 are respectively recorded as baseline vectorsThe unit direction vector from satellite to wireless device at time t 1 isAll are three-dimensional space vectors, and then:
Φd＝Φ1-Φ2,
Nd＝N1-N2,
Obtaining:
solving for baseline vectors Namely the position of the wireless device relative to the backscattering node, and the equation is deformed to obtain
The left side of the equal sign is an observed value and a known calculated value, the right side of the equal sign contains the quantity to be solved, the equation is a nonlinear equation at the moment and is difficult to solve, and then the nonlinear equation is solved in a linearization mode.
As shown in FIG. 9, the pair equation is in accordance with Newton's methodThe position of the device is linearly unfolded,
Recording device
Then:
the method comprises the steps of including 4 unknowns, namely three-dimensional position information of a base line vector and clock error of wireless equipment, and needing 4 linear independent equations to finish solving, and if the number of available satellites is m and the number of back scattering nodes is n, the solution can be finished by making m.n be more than or equal to 4.
An iterative weighted least Squares (WLS, weighted Least Squares) algorithm is then used:
substituting the back scattering node rebound signal and the direct signal into the calculation to obtain:
Wherein W represents a weight matrix, which is determined by the signal quality of the received satellite, and G is obtained by expanding a unit direction vector between the satellite and the receiving device. After a plurality of iterative WLS operations until the position converges to a certain range, substituting the position into the following formula to obtain the final position:
Wherein the method comprises the steps of Representing the actual baseline vector of the receiving device,An initial baseline vector representing the iteration is presented,Converging the vector for the baseline vector obtained by iteration. The obtained baseline vector is the relative position relative to the reference back scattering node, and the absolute position of the wireless equipment can be obtained through conversion.
As shown in fig. 4, the environment in the room is complex and changeable, so that the wireless signal is easy to generate complex multipath propagation in the room, and the signal propagation path received by the actual wireless device does not completely conform to the propagation path in the model, and a certain error is generated in the positioning result obtained by substituting the signal into the calculation, so that modeling correction is necessary to be performed on the multipath condition in the room to reduce the error. When the wireless device receives the navigation signal transmitted by the satellite, the wireless device can judge whether the received signal is a non-direct signal through the combination of parameter 'multipath zone bit' and 'carrier phase locking state', and on the basis, two multipath models are provided and analyzed, and the wireless device and the back scattering node are divided into direct path expansion and non-direct path expansion according to whether the sight line of the wireless device and the back scattering node is accessible.
In the expansion of the direct path, the direct path of the satellite is blocked, the satellite signal is received by the wireless device after being reflected by other reflecting surfaces, and the path expands relative to the original path at the moment, and half-wave loss is generated at the reflecting point:
H is the height of the wireless device held by the user, and is also the vertical height of the back scattering node deployment, and H is approximately equal to 1.2m.
In the expansion of the indirect path, the reflection path of the back scattering node is blocked, the reflection signal is received by the wireless device after being reflected by other reflection surfaces, and at the moment, the path expands relative to the original path, and half-wave loss is generated at the reflection point:
The value can be determined with few iterations.
Wherein H is the height of the wireless device held by the user, and is also the vertical height of the back scattering node deployment, and H is approximately equal to 1.2m; the value can be determined with few iterations, The length of the geometric propagation path of the signal received by the wireless device at the time t 1,t2 is respectively, namely the actual propagation distance of the signal; the geometrical distances from the satellite to the backscattering node at time t 1,t2 are respectively recorded as baseline vectors The unit direction vector from satellite to wireless device at time t 1 isAre all three-dimensional space vectors, and are used for generating a three-dimensional space vector,As the direction vector of the satellite to the backscatter node,As a direction vector from the backscatter node to the earth's center,Is an error correction term obtained by searching in the range of 0-2H.
By using the two error analysis models, the method can flexibly calculate in an actual scene, reduce errors and finally obtain accurate indoor positioning.
According to the invention, the wireless equipment does not need to be changed in hardware or driving, and accurate positioning can be realized even in an environment that the number of indoor visible satellites is difficult to meet the traditional positioning algorithm.
The invention also provides an indoor satellite positioning system for multipath error correction, which is used for realizing the indoor satellite positioning method for multipath error correction, and specifically comprises the following steps:
The original signal measurement module is used for receiving the blocked signal when the GNSS satellite transmits the wireless signal, receiving the direct path GNSS satellite signal without the blocking and the GNSS satellite signal rebounded by the backscattering node, and returning the original measurement information of the signal;
The multipath error correction module is used for calculating the actual position of the satellite corresponding to the received satellite signal after the wireless device acquires the ephemeris data of the satellite from the network, acquiring the known position of the back scattering node, combining the original measurement information of the received satellite signal, building a model according to the reflection state of the back scattering node, listing an observation equation, and solving the position of the wireless device.
Fig. 2 is a schematic diagram of an embodiment of an electronic device according to an embodiment of the present invention. As shown in fig. 2, the embodiment of the present invention provides an electronic device, which includes a memory 1310, a processor 1320, and a computer program 1311 stored in the memory 1310 and executable on the processor 1320, wherein when the processor 1320 executes the computer program 1311, the steps of S1, a GNSS satellite transmits a wireless signal, when the signal is blocked, the indoor wireless device cannot receive the blocked signal, and returns the original measurement information of the signal by receiving the direct path GNSS satellite signal without blocking and the GNSS satellite signal rebounded by the back scattering node;
S2, after the wireless equipment acquires ephemeris data of the satellite from the network, the actual position of the satellite corresponding to the received satellite signal can be calculated, the known position of the back scattering node is acquired, the model is built according to the reflection state of the back scattering node by combining the original measurement information of the received satellite signal, an observation equation is listed, and the position of the wireless equipment is solved.
Fig. 3 is a schematic diagram of an embodiment of a computer readable storage medium according to the present invention. As shown in fig. 3, the present embodiment provides a computer readable storage medium 1400 having stored thereon a computer program 1411, which computer program 1411 when executed by a processor performs the steps of S1, GNSS satellites transmitting wireless signals, when the signals are blocked, the indoor wireless device being unable to receive the blocked signals, receiving direct path GNSS satellite signals without blocking and GNSS satellite signals bounced by a backscatter node, and returning original measurement information of the signals;
S2, after the wireless equipment acquires ephemeris data of the satellite from the network, the actual position of the satellite corresponding to the received satellite signal can be calculated, the known position of the back scattering node is acquired, the model is built according to the reflection state of the back scattering node by combining the original measurement information of the received satellite signal, an observation equation is listed, and the position of the wireless equipment is solved.
In the foregoing embodiments, the descriptions of the embodiments are focused on, and for those portions of one embodiment that are not described in detail, reference may be made to the related descriptions of other embodiments.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims (7)

1.一种多径误差修正的室内卫星定位方法，其特征在于，包括以下步骤：1. A method for indoor satellite positioning with multipath error correction, characterized in that it comprises the following steps: S1，GNSS卫星发射无线信号，当信号有遮挡时，室内的无线设备无法收到被遮挡的信号，通过收到无遮挡的直射路径GNSS卫星信号和背向散射节点反弹的GNSS卫星信号，并返回信号的原始测量信息；S1, GNSS satellite transmits wireless signals. When the signal is blocked, the indoor wireless device cannot receive the blocked signal. It receives the unobstructed direct path GNSS satellite signal and the GNSS satellite signal bounced by the backscattering node, and returns the original measurement information of the signal; S2，无线设备从网络获取到卫星的星历数据后，可计算出收到的卫星信号对应卫星的实际位置，获取背向散射节点的已知位置，结合接收到的卫星信号的原始测量信息，根据背向散射节点的反射状态建立模型，列出观测方程，求解无线设备的位置；S2, after the wireless device obtains the satellite's ephemeris data from the network, it can calculate the actual position of the satellite corresponding to the received satellite signal, obtain the known position of the backscattering node, combine the original measurement information of the received satellite signal, establish a model based on the reflection state of the backscattering node, list the observation equation, and solve the position of the wireless device; 所述S2具体包括：根据无线设备与背向散射节点是否视线可及，分为直射路径膨胀和非直射路径膨胀；S2 specifically includes: dividing into direct path expansion and indirect path expansion according to whether the wireless device and the backscatter node are in line of sight; 状态一，直射路径膨胀，t1时刻背向散射节点反弹信号，无线设备能同时接收到来自卫星直射路径的信号和来自背向散射节点的信号，即为二者信号的加和；State 1: The direct path expands. At time t1, the backscatter node bounces the signal. The wireless device can simultaneously receive the signal from the satellite direct path and the signal from the backscatter node, which is the sum of the two signals. 状态二，t2时刻背向散射节点吸收信号，无线设备仅能接收到来自卫星的直射路径信号；State 2: At time t 2 , the backscattering node absorbs the signal, and the wireless device can only receive the direct path signal from the satellite; 所述S2具体包括：The S2 specifically includes: 状态一，实际传播距离为：State 1, the actual propagation distance is: 状态二，实际传播距离为：State 2, the actual propagation distance is: 其中，H为用户手持无线设备的高度，也是背向散射节点部署的垂直高度；能够通过很少的迭代确定取值，分别为t1,t2时刻下无线设备接收到信号的几何传播路径的长度，即信号的实际传播距离；分别为t1,t2时刻卫星到背向散射节点的几何距离，记从背向散射节点到无线设备的向量为基线向量为卫星到背向散射节点的方向矢量,为背向散射节点到地心的方向矢量,是误差校正项，通过在0-2H范围内搜索获得。Where H is the height of the user's handheld wireless device, which is also the vertical height of the backscatter node deployment; The value can be determined with very few iterations, are the lengths of the geometric propagation paths of the signals received by the wireless device at time t 1 and t 2 , i.e., the actual propagation distances of the signals; are the geometric distances from the satellite to the backscatter node at time t 1 and t 2 respectively, and the vector from the backscatter node to the wireless device is called the baseline vector is the direction vector from the satellite to the backscatter node, is the direction vector from the backscattering node to the center of the earth, is the error correction term, obtained by searching in the range of 0-2H. 2.根据权利要求1所述的多径误差修正的室内卫星定位方法，其特征在于，所述S2具体包括：2. The indoor satellite positioning method with multipath error correction according to claim 1, wherein S2 specifically comprises: 当所述背向散射节点反弹信号时，无线设备接收到的信号为GNSS卫星直射的信号和背向散射节点反弹的信号的总和；When the backscatter node bounces the signal, the signal received by the wireless device is the sum of the signal directly emitted by the GNSS satellite and the signal bounced by the backscatter node; 当背向散射节点不反弹信号时，无线设备接收到的信号为GNSS卫星直射的信号；无线设备根据接收到的信号返回原始测量信息。When the backscatter node does not bounce the signal, the signal received by the wireless device is the signal directly emitted by the GNSS satellite; the wireless device returns the original measurement information based on the received signal. 3.根据权利要求2所述的多径误差修正的室内卫星定位方法，其特征在于，所述无线设备接收信号后需要先分离背向散射节点反弹的信号，具体地，根据背向散射节点能够对微弱信号提供可观增益和GNSS卫星信号接收模块能够计算出接收端GNSS信号强度的特点，检测背向散射节点反弹的信号。3. According to the multipath error corrected indoor satellite positioning method described in claim 2, it is characterized in that after the wireless device receives the signal, it is necessary to first separate the signal bounced by the backscatter node. Specifically, based on the characteristics that the backscatter node can provide considerable gain for weak signals and the GNSS satellite signal receiving module can calculate the GNSS signal strength at the receiving end, the signal bounced by the backscatter node is detected. 4.根据权利要求1所述的多径误差修正的室内卫星定位方法，其特征在于，所述S1具体包括：当卫星数量不足时，利用背向散射节点与接收到的卫星进行组合定位。4. The indoor satellite positioning method with multipath error correction according to claim 1 is characterized in that S1 specifically includes: when the number of satellites is insufficient, combining positioning with backscatter nodes and received satellites. 5.一种多径误差修正的室内卫星定位系统，其特征在于，所述系统用于实现如权利要求1-4任一项所述的多径误差修正的室内卫星定位方法，具体包括：5. A multipath error corrected indoor satellite positioning system, characterized in that the system is used to implement the multipath error corrected indoor satellite positioning method according to any one of claims 1 to 4, specifically comprising: 原始信号测量模块，用于当GNSS卫星发射无线信号有遮挡时，室内的无线设备无法收到被遮挡的信号，通过收到无遮挡的直射路径GNSS卫星信号和背向散射节点反弹的GNSS卫星信号，并返回信号的原始测量信息；The original signal measurement module is used to receive the unobstructed direct path GNSS satellite signal and the GNSS satellite signal bounced by the backscattering node when the wireless signal transmitted by the GNSS satellite is blocked. The indoor wireless device cannot receive the blocked signal, and returns the original measurement information of the signal; 多径误差修正模块，用于在无线设备从网络获取到卫星的星历数据后，可计算出收到的卫星信号对应卫星的实际位置，获取背向散射节点的已知位置，结合接收到的卫星信号的原始测量信息，根据背向散射节点的反射状态建立模型，列出观测方程，求解无线设备的位置。The multipath error correction module is used to calculate the actual position of the satellite corresponding to the received satellite signal after the wireless device obtains the satellite's ephemeris data from the network, obtain the known position of the backscatter node, combine the original measurement information of the received satellite signal, establish a model according to the reflection state of the backscatter node, list the observation equation, and solve the position of the wireless device. 6.一种电子设备，其特征在于，包括存储器、处理器，所述处理器用于执行存储器中存储的计算机管理类程序时实现如权利要求1-4任一项所述的多径误差修正的室内卫星定位方法的步骤。6. An electronic device, characterized in that it comprises a memory and a processor, wherein the processor is used to implement the steps of the indoor satellite positioning method for multipath error correction as described in any one of claims 1 to 4 when executing a computer management program stored in the memory. 7.一种计算机可读存储介质，其特征在于，其上存储有计算机管理类程序，所述计算机管理类程序被处理器执行时实现如权利要求1-4任一项所述的多径误差修正的室内卫星定位方法的步骤。7. 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 satellite positioning method with multipath error correction as described in any one of claims 1 to 4 are implemented.
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