CN114779298A - Indoor satellite positioning method and system for multipath error correction - Google Patents

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

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CN114779298A
CN114779298A CN202210305211.0A CN202210305211A CN114779298A CN 114779298 A CN114779298 A CN 114779298A CN 202210305211 A CN202210305211 A CN 202210305211A CN 114779298 A CN114779298 A CN 114779298A
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satellite
signal
node
signals
backscattering
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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

Abstract

The invention belongs to the technical field of indoor satellite positioning, and particularly provides an indoor satellite positioning method and system for correcting multipath errors, wherein the method comprises the steps that a GNSS satellite transmits a wireless signal, when the signal is shielded, indoor wireless equipment cannot receive the shielded signal, and original measurement information of the signal is returned by receiving a direct path GNSS satellite signal without shielding and a GNSS satellite signal rebounded by a backscattering node; after the wireless device acquires ephemeris data of a satellite from a network, the actual position of the satellite corresponding to the received satellite signal can be calculated, the known position of the backscatter node is acquired, a model is established according to the reflection state of the backscatter node by combining the original measurement information of the received satellite signal, an observation equation is listed, and the position of the wireless device is solved. The backscattering node with low power consumption, small volume and low price is attached to the position of the visible sky around the wireless device, and the wireless device can be any device capable of receiving 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 positioning satellite systems (GNSS) have become an indispensable tool for many emerging location-based services, such as navigation, taxi taking, Augmented Reality (AR), and the like. The satellite positioning technology has the following characteristics:
(1) using global coordinate system (ECEF) without depending on 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 visible satellites in the room, lack of direct paths, large propagation loss in the building and the like, and cannot be used indoors. In an indoor environment, namely, GNSS satellite signals which can be received by the wireless device are weak, the number of the satellite signals which can be received is small, the position information of the wireless device is unknown, and the wireless device only needs to be positioned by deploying one or more backscattering nodes which are low in power consumption, small in size and low in price in the surrounding visible sky. For example, in a mall or station, guests may use backscatter nodes deployed near a window for indoor location. The indoor satellite positioning is realized in order to solve the problem of indoor application of the satellite positioning technology. In the existing methods, the disclosed articles 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 closed flowing. ieee Transactions on Mobile computing 15,6 (136), 1348 + nihri 1 and Shahriar Nirjon, Jie Liu, gerad DeJean, Bodhi Priyantha, yuzhhe Jin, and Ted hart.2014.coin-GPS: index localization analysis, in front computing 12 and satellite coverage area, and the integration of these signals into the receiving terminal is usually achieved by using high gain amplifiers, which are more efficient than the above mentioned in the conventional approaches, and are more efficient than the above mentioned in the conventional approaches.
Therefore, a set of low-power-consumption indoor satellite positioning scheme suitable for handheld wireless equipment is lacking at present.
Disclosure of Invention
The invention aims at the technical problem of high power consumption of indoor satellite positioning in the prior art.
The invention provides an indoor satellite positioning method for correcting multipath errors, which comprises the following steps:
s1, the GNSS satellite emits wireless signals, when the signals are shielded, indoor wireless equipment cannot receive the shielded signals, and the GNSS satellite signals rebounded from the backscattering nodes are received through direct paths without shielding, and original measurement information of the signals is returned;
s2, after the wireless device 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 can be acquired, a 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 device is solved.
Preferably, the S2 specifically includes:
when the back scattering node rebounds the signal, the signal received by the wireless equipment is the sum of the direct signal of the GNSS satellite and the signal rebounded by the back scattering node;
when the back scattering node does not bounce back signals, the signals received by the wireless equipment are direct signals of the GNSS satellite; the wireless device returns raw measurement information based on the received signal.
Preferably, the wireless device needs to separate a signal rebounded by the backscatter node after receiving the signal, and specifically, the signal rebounded by the backscatter node is detected according to the characteristics that the backscatter node can provide an observable gain for a weak signal and the GNSS satellite signal receiving module can calculate the GNSS signal strength of the receiving end.
Preferably, the S1 specifically includes: and when the number of the satellites is insufficient, performing combined positioning by using the backscattering node and the received satellites.
Preferably, the S2 specifically includes: dividing the expansion into direct path expansion and indirect path expansion according to whether the wireless equipment and the backscattering node have the visual line reach;
state one, direct path expansion, t1Time of dayThe signal is rebounded by the backscattering node, and the wireless equipment can simultaneously receive the signal from the direct path of the satellite and the signal from the backscattering node, namely the sum of the signals of the direct path of the satellite and the signal from the backscattering node;
state two, t2The time backscatter node absorbs the signal 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:
Figure BDA0003564534920000031
in state two, the actual propagation distance is:
Figure BDA0003564534920000032
wherein H is the height of the wireless equipment held by the user and is also the vertical height of the deployment of the backscattering node;
Figure BDA0003564534920000041
the value can be determined by a few iterations,
Figure BDA0003564534920000042
are each t1,t2The length of a geometric propagation path of a signal received by a wireless device at a moment, namely the actual propagation distance of the signal;
Figure BDA0003564534920000043
are each t1,t2The geometrical distance from the satellite to the backscattering node at the moment is recorded as a vector from the backscattering node to the wireless device as a baseline vector
Figure BDA0003564534920000044
Figure BDA0003564534920000045
The direction vector from the satellite to the backscatter node,
Figure BDA0003564534920000046
is the direction vector of the backscatter node to the geocenter,
Figure BDA0003564534920000047
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 GNSS satellite signals and backscattering the GNSS satellite signals reflected by the nodes and returning original measurement information of the signals when the GNSS satellite transmits the radio signals in a shielding manner and indoor radio equipment cannot receive the shielded signals;
the multi-path error correction module is used for calculating the actual position of the satellite corresponding to the received satellite signal after the wireless equipment acquires ephemeris data of the satellite from a network, acquiring the known position of the backscattering node, establishing a model according to the reflection state of the backscattering node by combining the original measurement information of the received satellite signal, listing an observation equation and solving the position of the wireless equipment.
The invention also provides electronic equipment which comprises a memory and a processor, wherein the processor is used for implementing the steps of the indoor satellite positioning method for correcting the multipath error when the processor executes the computer management program stored in the memory.
The present invention also provides a computer readable storage medium having stored thereon a computer management like program for implementing the steps of the method for indoor satellite based positioning with multipath error correction when executed by a processor.
Has the advantages that: the invention provides an indoor satellite positioning method and system for multipath error correction, wherein the method comprises the steps that a GNSS satellite emits wireless signals, when the signals are shielded, indoor wireless equipment cannot receive the shielded signals, direct path GNSS satellite signals without shielding and GNSS satellite signals rebounded by backscattering nodes are received, and original measurement information of the signals is returned; after the wireless device acquires ephemeris data of a satellite from a network, the actual position of the satellite corresponding to the received satellite signal can be calculated, the known position of the backscatter node is acquired, a model is established according to the reflection state of the backscatter node by combining the original measurement information of the received satellite signal, an observation equation is listed, and the position of the wireless device is solved. The scheme has low power consumption, small volume and low price, the backscattering node is attached to the position of the 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 for multipath error correction according to the present invention;
FIG. 2 is a schematic diagram of a hardware structure of a possible electronic device provided in the present invention;
FIG. 3 is a schematic diagram of a hardware structure of a possible computer-readable storage medium provided by the present invention;
FIG. 4 is a schematic diagram of the modeling and correction of the indoor multipath situation provided by 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 of the 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 shows t provided by the present invention1And t2Schematic diagrams of two states at a moment;
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 detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
As shown in fig. 1, the indoor satellite positioning method for multipath error correction according to the embodiment of the present invention includes that a GNSS satellite transmits a wireless signal, when the signal is blocked, an indoor wireless device cannot receive the blocked signal, receives a direct path GNSS satellite signal without blocking and a GNSS satellite signal bounced by a backscatter node, and returns original measurement information of the signal; after the wireless equipment acquires ephemeris data of a satellite from a network, the actual position of the satellite corresponding to the received satellite signal can be calculated, the known position of the backscattering node is acquired, a model is built according to the reflection state of the backscattering 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. The backscattering node with low power consumption, small volume and low price is attached to the position of the 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 on the wireless device, and is easy to deploy and popularize. Deploying a backscattering node through a wireless device needing positioning indoors; the wireless device receives a Satellite Navigation System (GNSS) Satellite signal and a direct GNSS Satellite signal which are reflected by the back scattering node; separating the carrier-to-noise ratio of the GNSS signals to obtain backscattering node rebounding signals and direct GNSS satellite signals; and measuring the accumulated carrier phase of the GNSS satellite signals of the direct path and the reflected path, fusing the reference position information of the GNSS satellite ephemeris and the backscatter node, and positioning the position of the indoor wireless equipment. According to the invention, under the conditions that the number of indoor visible GNSS satellites is small and GNSS satellite signals are weak, the backscattering signal emission circuit is controlled to switch between rebounding GNSS signals and absorbing GNSS signals, so that accurate indoor positioning of wireless equipment is realized.
The backscattering node with low power consumption, small volume and low price is attached to the position of the 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, GNSS satellite signals that can be received by a wireless device are weak, the number of satellite signals that can be received is small, location information of the wireless device is unknown, and the wireless device only needs to be located by deploying one or more low-power, small-size, and low-cost backscatter nodes in the visible sky around. For example, in a mall or station, guests may use back-scattering nodes deployed near the window for indoor positioning.
Based on the scene, one or more backscattering nodes with low power consumption, small volume and low price are attached to the position of the 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 signals to change the multipath propagation characteristics of the wireless signals, ultimately helping to locate the wireless device indoors.
The invention designs that the backscattering node is attached to the visible sky position around the wireless equipment, and the backscattering node is used for rebounding the wireless signal to change the multipath propagation of the wireless signal; the embodiments of the present invention include the following techniques:
(1) backscattering assisted positioning technology: 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 value of the satellite signals is sampled in a short time for modeling by combining the known position coordinates of the backscatter nodes.
The traditional positioning model needs to have signal data of at least four satellites, and in the positioning model established in the patent, when the number of satellites is insufficient, the backscattering node can be used for carrying out combined positioning with the received satellites, so that the minimum number of satellites participating in positioning is less than that of the traditional positioning. For example, in an indoor environment, a mobile phone can only receive signals from a satellite a and a satellite B, the number of satellites is 2 and is smaller than 4 satellites required by a traditional positioning model, after backscattering nodes a and B are deployed at appropriate positions, two satellites and two backscattering nodes are shared, the mobile phone can receive signals directly from the satellite a and the satellite B and reflected signals from the backscattering nodes a and B, and the position of the mobile phone can be obtained through combined modeling to complete positioning. As shown in fig. 6.
(2) Multipath error correction technique: because the indoor environment is complicated, and the satellite moves relative to the ground, receiving terminal wireless equipment may be difficult to receive the direct signal of the satellite, but the reflected signal of other indoor reflection surfaces, and simultaneously there may be the blockking between backscatter node and the receiving terminal wireless equipment for the signal that is amplified and reflected through backscatter node can't be directed directly to receiving terminal wireless equipment, thereby brings positioning error. The two cases are divided into the path expansion caused by multipath reflection when the backscattering node is in the line of sight of the wireless device at the receiving end and not in the line of sight.
The specific scheme principle process is as follows:
(1) as shown in fig. 5, the GNSS satellite transmits a wireless signal, and when the signal is blocked, the indoor wireless device cannot receive the blocked signal, can receive the unblocked direct path GNSS satellite signal and the GNSS satellite signal reflected by the backscatter node, and returns the original measurement information of the signal; after the wireless equipment carries out noise elimination on the carrier-to-noise ratio of the signal, separating original signal measurement information corresponding to a backscattering node rebound path and original signal measurement information which does not rebound from the backscattering node according to the carrier-to-noise ratio strength characteristic of the signal;
(2) as shown in fig. 6, after acquiring ephemeris data of a satellite from a network, a wireless device may calculate an actual position of the satellite corresponding to a received satellite signal, acquire a known position of a backscatter node, combine original measurement information of the received satellite signal, establish a model according to two states of the backscatter node, list an observation equation, and solve a position of the wireless device;
(3) as shown in fig. 7, the indoor conditions of the wireless device are complex, two common models of indoor multipath errors are proposed to improve the accuracy of indoor positioning and enhance robustness, and the models are corrected to reduce errors.
Specifically, the GNSS satellite transmits a wireless positioning signal, the wireless device receives the signal indoors, and when the signal bounces back to the backscatter node, the signal received by the wireless device is the sum of a direct signal of the GNSS satellite and a signal bounced back to the backscatter node; when the back scattering node does not bounce back signals, the signals received by the wireless equipment are direct signals of the GNSS satellite; the wireless device returns raw measurement information based on the received signal.
As shown in fig. 8, the wireless device first needs to separate the signals bouncing off the backscatter node. According to the scheme, the characteristic that the backscatter node can provide observable gain for weak signals and the characteristic that the GNSS satellite signal receiving module can calculate the GNSS signal intensity of the receiving end are utilized, and the signals rebounded by the backscatter node are detected.
The backscattering node has the characteristics of high sensitivity and high gain, and can perform reflection amplification on a GNSS satellite signal weak on the ground. When the backscattering node rebounds signals, the wireless equipment receives the sum of the GNSS satellite signals and the backscattering node rebounding signals, and compared with the case that the backscattering node does not rebound signals, the wireless equipment can only receive direct GNSS satellite signals, and the strength of amplified sum signals is stronger than that of direct path signals. In the raw measurement information of the GNSS satellite signal, the carrier-to-noise ratio, i.e., the carrier-to-noise ratio, can intuitively reflect the strength of the signal.
As shown in FIG. 8, the system state is divided into two states, t, according to the reflection state of the backscatter node2The backscattering node absorbs signals at all times, and the wireless equipment can only receive direct path signals from a satellite; t is t1And the wireless equipment can simultaneously receive the signal from the direct path of the satellite and the signal from the backscattering node, namely the sum of the signals of the direct path of the satellite and the signal from the backscattering node.
Signals of the GNSS satellite reach the ground through the atmosphere at any time, and electromagnetic waves can be scattered, reflected and diffracted in an ionosphere and a troposphere in the atmosphere, so that the signals are delayed for a certain time. In positioning systems of GNSS receivers, the determination of position is determined by the measurement of the signal propagation path, so the positioning accuracy depends on the precise measurement of the signal propagation time, while the errors introduced by the atmosphere vary with time and are difficult to measure and estimate accurately, so the distance estimation errors generated by ionospheric and tropospheric delays are recorded as I, T, respectively.
Note the book
Figure BDA0003564534920000101
Are each t1,t2The length of the geometric propagation path of the signal received by the wireless device at the time instant, i.e., the actual propagation distance of the signal. In order to improve the positioning accuracy, the phase of the carrier wave of the GNSS satellite is measured on the wireless device, recorded as Φ, and has a distance unit, which represents the accumulated wave path after the wireless device captures the carrier wave signal of the locked satellite, and since the carrier wave signal is periodic, the whole-cycle ambiguity distance error N will be generated during locking. The receiving end wireless equipment measures the signal propagation time delay, the difference between the clock stability of a local system and the satellite-borne atomic clock performance of a satellite is called clock error, and the generated distance error is marked as (t)(R,t)-t(S,t)). For two adjacent different states:
t1:
Figure BDA0003564534920000102
t2:
Figure BDA0003564534920000103
t1,t2the time interval is short, the atmospheric layer state can be regarded as unchanged, and the generated atmospheric layer time delay keeps consistent;
Figure BDA0003564534920000104
the distance error caused by the propagation delay of the signal in the backscattering node can be measured by an instrument, and epsilonΦIndicating errors in phase measurementsA difference term; because the satellite is far away from the ground, the distance from the backscattering node to the wireless equipment is far less than the distance from the backscattering node to the satellite, and the signal of the satellite can be considered to arrive at the ground in parallel; note the book
Figure BDA0003564534920000111
Are each t1,t2The geometrical distance from the satellite to the backscattering node at the moment is recorded as a vector from the backscattering node to the wireless device as a baseline vector
Figure BDA0003564534920000112
t1The unit direction vector from the satellite to the wireless device at the moment of time is
Figure BDA0003564534920000113
All are three-dimensional space vectors, then there are:
Figure BDA0003564534920000114
Figure BDA0003564534920000115
Figure BDA0003564534920000116
Φd＝Φ1-Φ2,
Nd＝N1-N2,
Figure BDA0003564534920000117
obtaining:
Figure BDA0003564534920000118
solving for baseline vectors
Figure BDA0003564534920000119
Namely the position of the wireless equipment relative to the backscattering node, and the equation is transformed
Figure BDA00035645349200001110
The left side of the equal sign is an observed value and a known calculated value, the right side of the equal sign contains a quantity to be solved, the equation is a nonlinear equation and is difficult to solve, and then the nonlinear equation is solved in a linear mode.
As shown in fig. 9, the equation is shown in accordance with newton's method
Figure BDA0003564534920000121
The linear spread-out is performed,
Figure BDA0003564534920000122
note book
Figure BDA0003564534920000123
Then:
Figure BDA0003564534920000124
the method comprises the steps that 4 unknowns are included, three-dimensional position information of a baseline vector and clock error of wireless equipment are respectively included, 4 linearly independent equations are needed to complete solution, and if the number of available satellites is m, the number of backscattering nodes is n, and m & n is larger than or equal to 4, the solution can be completed.
An iterative Weighted Least Squares (WLS) algorithm is then used:
Figure BDA0003564534920000125
and substituting the backscattering node rebound signal and the direct signal into the calculation to obtain:
Figure BDA0003564534920000131
where W represents a weight matrix determined by the received satellite signal quality and G is derived from the unit direction vector spread between the satellite and the receiving device. After several times of iterative WLS operation until the position converges to a certain range, substituting the position into the following formula to obtain the final position:
Figure BDA0003564534920000132
wherein
Figure BDA0003564534920000133
Representing the actual baseline vector of the receiving device,
Figure BDA0003564534920000134
an initial baseline vector representing an iteration is shown,
Figure BDA0003564534920000135
is the baseline vector convergence vector obtained by iteration. The obtained baseline vector is relative position relative to the reference backscattering node, and the absolute position of the wireless device can be obtained through conversion.
As shown in fig. 4, since the indoor environment is complicated and changeable, the wireless signal is easy to generate complicated multipath propagation indoors, so that the propagation path of the signal received by the actual wireless device does not completely conform to the propagation path in the model, and a certain error will be generated by substituting the calculated positioning result, so that it is necessary to perform modeling correction on the indoor multipath situation to reduce the error. When the wireless equipment receives a navigation signal transmitted by a satellite, whether the received signal is an indirect signal or not can be judged through the parameters of the multipath zone bit and the carrier phase locking state, on the basis, two multipath models are provided and analyzed, and direct path expansion and indirect path expansion are divided according to whether the wireless equipment and a backscattering node are in sight.
In the expansion of the direct path, the direct path of the satellite is shielded, satellite signals are received by wireless equipment after being reflected by other reflecting surfaces, and the path expands to some extent relative to the original path and generates half-wave loss at a reflecting point:
Figure BDA0003564534920000141
h is the height of the user handheld wireless equipment and the vertical height of the backscattering node deployment, and H is approximately equal to 1.2 m.
In the expansion of the non-direct path, a reflection path of a backscattering node is shielded, a reflection signal is received by wireless equipment after being reflected by other reflection surfaces, and the path is expanded to some extent relative to the original path and generates half-wave loss at a reflection point:
Figure BDA0003564534920000142
Figure BDA0003564534920000143
the values can be determined with few iterations.
H is the height of the wireless equipment held by a user and is also the vertical height of the backscattering node deployment, and H is approximately equal to 1.2 m;
Figure BDA0003564534920000144
the value can be determined by a few iterations,
Figure BDA0003564534920000145
are each t1,t2The length of a geometric propagation path of a signal received by a wireless device at a moment, namely the actual propagation distance of the signal;
Figure BDA0003564534920000146
are each t1,t2The geometrical distance from the satellite to the backscattering node at the moment is recorded as a vector from the backscattering node to the wireless device as a baseline vector
Figure BDA0003564534920000147
t1The unit direction vector from the satellite to the wireless device at the moment of time is
Figure BDA0003564534920000148
Are all three-dimensional space vectors,
Figure BDA0003564534920000149
the direction vector from the satellite to the backscatter node,
Figure BDA00035645349200001410
is the direction vector of the backscatter node to the geocenter,
Figure BDA00035645349200001411
is an error correction term obtained by searching in the range of 0-2H.
By utilizing 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, hardware or drive modification of wireless equipment is not required, and accurate positioning can be realized even in the 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 GNSS satellite signals on the direct path without shielding and the GNSS satellite signals rebounded by the backscattering nodes when the GNSS satellite transmits the radio signals with shielding, and returning original measurement information of the signals;
the multi-path error correction module is used for calculating the actual position of the satellite corresponding to the received satellite signal after the wireless equipment acquires ephemeris data of the satellite from a network, acquiring the known position of the backscattering node, establishing a model according to the reflection state of the backscattering node by combining the original measurement information of the received satellite signal, listing an observation equation and solving the position of the wireless equipment.
Fig. 2 is a schematic diagram of an electronic device according to an embodiment of the invention. As shown in fig. 2, an 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 operable on the processor 1320, where the processor 1320, when executing the computer program 1311, implements the following steps: s1, the GNSS satellite emits wireless signals, when the signals are shielded, indoor wireless equipment cannot receive the shielded signals, and original measurement information of the signals is returned by receiving the direct path GNSS satellite signals without shielding and the GNSS satellite signals rebounded by the backscattering nodes;
s2, after the wireless device 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 can be acquired, a 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 device is solved.
Please refer to fig. 3, which 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, on which a computer program 1411 is stored, which computer program 1411, when executed by a processor, implements the steps of: s1, the GNSS satellite emits wireless signals, when the signals are shielded, indoor wireless equipment cannot receive the shielded signals, and original measurement information of the signals is returned by receiving the direct path GNSS satellite signals without shielding and the GNSS satellite signals rebounded by the backscattering nodes;
s2, after acquiring ephemeris data of a satellite from a network, the wireless device can calculate the actual position of the satellite corresponding to the received satellite signal, acquire the known position of the backscatter node, establish a model according to the reflection state of the backscatter node by combining the original measurement information of the received satellite signal, list an observation equation, and solve the position of the wireless device.
It should be noted that, in the foregoing embodiments, the description of each embodiment has an emphasis, and reference may be made to the related description of other embodiments for a part that is not described in detail in a certain embodiment.
As will be appreciated by one skilled in the art, 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. Therefore, it is intended that the appended claims be interpreted as including 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 changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (9)

1. An indoor satellite positioning method for multipath error correction, comprising the steps of:
s1, the GNSS satellite emits wireless signals, when the signals are shielded, indoor wireless equipment cannot receive the shielded signals, and original measurement information of the signals is returned by receiving the direct path GNSS satellite signals without shielding and the GNSS satellite signals rebounded by the backscattering nodes;
s2, after acquiring ephemeris data of a satellite from a network, the wireless device can calculate the actual position of the satellite corresponding to the received satellite signal, acquire the known position of the backscatter node, establish a model according to the reflection state of the backscatter node by combining the original measurement information of the received satellite signal, list an observation equation, and solve the position of the wireless device.
2. The multipath error corrected indoor satellite positioning method according to claim 1, wherein the S2 specifically includes:
when the back scattering node rebounds the signal, the signal received by the wireless equipment is the sum of the direct signal of the GNSS satellite and the signal rebounded by the back scattering node;
when the back scattering node does not bounce back signals, the signals received by the wireless equipment are direct signals of the GNSS satellite; the wireless device returns raw measurement information based on the received signal.
3. The indoor multipath error corrected satellite positioning method of claim 2, wherein the wireless device needs to separate the signal bounced off the backscatter node after receiving the signal, and specifically, detects the signal bounced off the backscatter node according to the characteristics that the backscatter node can provide an observable gain for a weak signal and the GNSS satellite signal receiving module can calculate the GNSS signal intensity at the receiving end.
4. The method for multipath error corrected indoor satellite positioning according to claim 1, wherein the S1 specifically comprises: and when the number of the satellites is insufficient, performing combined positioning with the received satellites by using the backscatter nodes.
5. The method for multipath error corrected indoor satellite positioning according to claim 1, wherein the S2 specifically comprises: dividing the expansion into direct path expansion and indirect path expansion according to whether the wireless equipment and the backscattering node have the visual line reach;
state one, direct path expansion, t1The signal is rebounded from the backscattering node at all times, and the wireless equipment can simultaneously receive the signal from the direct path of the satellite and the signal from the backscattering node, namely the sum of the signals of the two signals;
state two, t2The time backscatter node absorbs the signal and the wireless device can only receive the direct path signal from the satellite.
6. The multipath error corrected indoor satellite positioning method of claim 5, wherein the S2 specifically includes:
in state one, the actual propagation distance is:
Figure FDA0003564534910000021
in state two, the actual propagation distance is:
Figure FDA0003564534910000022
wherein H is the height of the wireless equipment held by the user, and is also the vertical height of the backscattering node deployment;
Figure FDA0003564534910000023
the value can be determined by a few iterations,
Figure FDA0003564534910000024
are each t1,t2The length of a geometric propagation path of a signal received by a wireless device at a moment, namely the actual propagation distance of the signal;
Figure FDA0003564534910000025
are each t1,t2The geometric distance from the satellite to the backscattering node at the moment is recorded as a vector from the backscattering node to the wireless device as a baseline vector
Figure FDA0003564534910000026
The direction vector from the satellite to the backscatter node,
Figure FDA0003564534910000027
is the direction vector of the backscatter node to the geocenter,
Figure FDA0003564534910000028
is an error correction term obtained by searching in the range of 0-2H.
7. A multipath error corrected indoor satellite positioning system, the system being configured to implement the multipath error corrected indoor satellite positioning method according to any one of claims 1 to 6, and specifically comprising:
the original signal measurement module is used for receiving the GNSS satellite signals on the direct path without shielding and the GNSS satellite signals rebounded by the backscattering nodes when the GNSS satellite transmits the radio signals with shielding, and returning original measurement information of the signals;
the multi-path error correction module is used for calculating the actual position of the satellite corresponding to the received satellite signal after the wireless equipment acquires ephemeris data of the satellite from a network, acquiring the known position of the backscattering node, establishing a model according to the reflection state of the backscattering node by combining the original measurement information of the received satellite signal, listing an observation equation and solving the position of the wireless equipment.
8. An electronic device comprising a memory, a processor for implementing the steps of the multipath error corrected indoor satellite positioning method of any one of claims 1-6 when executing a computer management like program stored in the memory.
9. A computer-readable storage medium, having stored thereon a computer management like program, which when executed by a processor, performs the steps of the multipath error corrected indoor satellite positioning method of any one of claims 1 to 6.
CN202210305211.0A 2022-03-25 2022-03-25 Indoor satellite positioning method and system for multipath error correction Pending CN114779298A (en)

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