阅读说明：本技术 转发式室内定位方法和装置 (Forwarding type indoor positioning method and device ) 是由 刘成 高为广 陈颖 于 2019-08-16 设计创作，主要内容包括：本发明提供一种转发式室内定位方法和装置。该方法包括：中心处理节点i发射无线电测距信号；锚节点j接收和解调来自所述中心处理节点i的无线电测距信号,重新调制成转发信号进行转发；所述中心处理节点i接收和解调来自所述锚节点j的转发信号；所述中心处理节点i计算所述锚节点j的锚节点虚拟钟差ΔT<Sub>ij</Sub>；所述用户终端k接收来自所述锚节点i的转发信号,和来自所述中心处理节点i的所述锚节点虚拟钟差ΔT<Sub>ij</Sub>,利用所述虚拟钟差ΔT<Sub>ij</Sub>,计算得到所述用户终端k与所述锚节点i之间的距离值ρ<Sub>kj</Sub>,并由此计算得到该用户终端k的位置坐标信息。利用本发明的方法和装置,能够在无需锚节点之间时间同步的情况下,实现室内高精度定位。(The invention provides a forwarding type indoor positioning method and a forwarding type indoor positioning device. The method comprises the following steps: a central processing node i transmits a radio ranging signal; the anchor node j receives and demodulates the radio ranging signal from the central processing node i, and the radio ranging signal is re-modulated into a forwarding signal for forwarding; the central processing node i receives and demodulates a forwarding signal from the anchor node j; the central processing node i calculates the anchor node virtual clock error delta T of the anchor node j ij (ii) a The user terminal k receives a forwarding signal from the anchor node i and the anchor node virtual clock error delta T from the central processing node i ij Using said virtual clock difference Δ T ij And calculating to obtain a distance value rho between the user terminal k and the anchor node i kj And calculating the position coordinate information of the user terminal k according to the position coordinate information. By utilizing the method and the device of the invention, indoor high-precision positioning can be realized under the condition of not needing time synchronization between anchor nodesa bit.)

1. A method of repeater indoor positioning, the method comprising the steps of:

The central processing node i transmits a radio ranging signal and marks the transmission moment in said radio ranging signalWherein i is more than or equal to 1;

The anchor node j receives and demodulates the radio ranging signal from the central processing node i and marks the moment of retransmissionThen modulating the signal into a forwarding signal again for forwarding, wherein j is more than or equal to 3;

The central processing node i receives and demodulates the forwarded signal from the anchor node j and records it at the centerReceiving time of forwarding signal of the anchor node j by the management node i

The central processing node i receives the forwarding signal of the anchor node j according to the central receiving node iThe transmission time of the radio ranging signal transmitted by the central processing node iAnd the distance between the anchor node j and the central processing node i measured in advanceTo calculate an anchor node virtual clock offset Δ T for the anchor node j_ijAnd sending the virtual clock error delta T of the anchor node to a user terminal k_ij；

The user terminal k receives a forwarding signal from the anchor node i and the anchor node virtual clock error delta T from the central processing node i_ijUsing said virtual clock difference Δ T_ijAnd calculating to obtain a distance value rho between the user terminal k and the anchor node i_kj；

According to the distance value rho between the user terminal k and a plurality of anchor nodes j_kjAnd calculating to obtain the position coordinate information of the user terminal k.

2. The forwarding indoor positioning method according to claim 1, wherein:

The radio ranging signal also comprises an ID identification number of the central processing node i;

The forwarding signal also comprises an ID identification number of the anchor node j.

3. The forwarding-type indoor positioning method as claimed in claim 1, further comprising:

Pre-measuring the distance between a looking-through anchor node j and a central processing node i using a laser rangefinderAnd the distance between the anchor node j and the central processing node iAnd sending the information to the central processing node i.

4. The method according to claim 1, wherein an anchor node virtual clock offset Δ T of the anchor node j is calculated after the central processing node i receives and demodulates the forwarded signal from the anchor node j_ijBefore, still include:

and the central processing node i screens out the modulated forwarding signals of the anchor node i which are in communication with the central processing node i from the demodulated forwarding signals.

5. the forwarding indoor positioning method according to claim 1,

The central processing node i is according to the formulaCalculating to obtain virtual clock error delta T of anchor node_ijWhereinFor the time of reception of the forwarded signal of the anchor node j by the central receiving node i,The transmission moment at which the radio ranging signal is transmitted for the central processing node i,To prepareThe distance between the anchor node j and the central processing node i is measured first, and c is 3 × 10⁸M/s.

6. The forwarding indoor positioning method according to claim 1, wherein the virtual clock difference Δ T is utilized_ijAnd calculating to obtain a distance value rho between the user terminal k and the anchor node i_kjThe method comprises the following steps:

The user terminal k is according to the formulaCalculating the corrected forwarding time of the anchor node j to the forwarding signalWhereinThe forwarding time, Δ T, of the signaling signal marked for the anchor node j_ijVirtualizing a clock error for the anchor node;

according to the formulacalculating to obtain a distance value rho from the user terminal k to the anchor node j_kjWherein t is_kjFor the moment of reception of the forwarded signal of the anchor node i by the user terminal k,The forwarding time of the forwarding signal is corrected for the anchor node j.

7. The forwarding-type indoor positioning method according to claim 6, wherein p is a distance value between the user terminal k and a plurality of anchor nodes j_kjThe step of calculating the position coordinate information of the user terminal k includes:

According to the formulaCalculating the abscissa X and the ordinate Y of the position coordinate of the user terminal k, where ρ_kjIs the distance value, X, from the user terminal k to the anchor node j_mis the abscissa, Y, of the position coordinate of the anchor node j_mIs the ordinate, Δ t, of the position coordinate of the anchor node j_kFor clock error, m is the number of anchor nodes i, m is more than or equal to 3, and c is 3 × 10⁸M/s.

8. the forwarding-type indoor positioning method according to claim 6, wherein p is a distance value between the user terminal k and a plurality of anchor nodes j_kjthe step of calculating the position coordinate information of the user terminal k includes:

According to the formulaCalculating the X, Y and Z coordinates of the position coordinates of the user terminal, where rho_kjIs the distance value, X, from the user terminal k to the anchor node j_mIs the abscissa, Y, of the position coordinate of the anchor node j_mIs the ordinate, Z, of the position coordinate of the anchor node j_mIs the vertical coordinate of the position coordinate of the anchor node j, m is the number of the anchor nodes i, m is more than or equal to 4, c is 3 multiplied by 10⁸M/s.

9. A repeater indoor positioning device, comprising:

A central processing node i equipped with an atomic clock, configured for transmitting a radio ranging signal and marking the transmission instants in said radio ranging signalWherein i is more than or equal to 1, receiving and demodulating the forwarding signal from the anchor node j, and recording the receiving time of the forwarding signal of the anchor node j by the central processing node iAccording to the forwarding signal of the central receiving node i to the anchor node jTime of reception ofThe transmission time of the radio ranging signal transmitted by the central processing node iAnd the distance between the anchor node j and the central processing node i measured in advanceTo calculate an anchor node virtual clock offset Δ T for the anchor node j_ijAnd sending the virtual clock error delta T of the anchor node to a user terminal k_ij；

A plurality of anchor nodes j with radio signal transmitting and receiving functions, wherein the anchor nodes j are configured to receive and demodulate radio ranging signals from the central processing node i and mark forwarding timeThen modulating the signal into a forwarding signal again for forwarding, wherein j is more than or equal to 3;

A user terminal k with radio signal receiving function, configured to receive the forwarded signal from the anchor node i, and the anchor node virtual clock difference Δ T from the central processing node i_ijUsing said virtual clock difference Δ T_ijAnd calculating to obtain a distance value rho between the user terminal k and the anchor node i_kjaccording to the distance value rho between the user terminal k and a plurality of anchor nodes j_kjAnd calculating to obtain the position coordinate information of the user terminal k.

10. The forwarding indoor positioning device as claimed in claim 9, wherein the central processing node is kept in line of sight with all or part of the plurality of anchor nodes j.

Technical Field

The invention relates to the field of internet of things, location-based services and indoor positioning. And more particularly, to a method and apparatus for repeater indoor positioning.

Background

With the increasing growth of the internet of things and the location-based service industry, the demand for indoor location services is also rapidly increasing and expanding. By utilizing the indoor positioning technology, the system not only can provide commercial services such as asset management, convenient guidance, accurate advertisement pushing and the like for people, but also can be used for processing and dredging under the conditions of indoor burst, emergency and the like, and has important commercial value and social significance.

Because it is difficult for navigation satellite signals such as a global positioning system GPS to effectively cover an indoor environment, indoor positioning is usually implemented based on an indoor anchor node. These anchor nodes may be different types of sensors including radio frequency tags RFID, wireless local area network Wi-Fi, BlueTooth, ZigBee, UWB ultra wide band, etc. In terms of an indoor positioning model and method, Time of Arrival (TOA) positioning is the most classical method, and determines the distance between a user terminal and a plurality of anchor node sensors by measuring the Arrival Time between the user terminal and the anchor node sensors, and then performs intersection solution to obtain the coordinate position of the user terminal.

Besides TOA, Fingerprint matching (Fingerprint) based on scene analysis is also a common indoor positioning method. In this type of method, the user terminal queries a feature database that has been established in advance using a measurement value such as a distance from the user terminal itself to the anchor node, and determines the position of the object according to a specific matching rule, which is substantially a pattern recognition method. At this time, although the user terminal does not need to determine the coordinate position of the user terminal through direct intersection calculation, the user terminal still needs to obtain the most accurate characteristic quantities such as distance measurement values and the like so as to perform more accurate and efficient characteristic database query and matching.

However, for a typical indoor positioning system, it is very difficult to obtain an accurate distance measurement between the user terminal and the anchor node, which requires strict time synchronization between the anchor nodes. According to estimation, a time synchronization error of 10ns between anchor nodes can cause a ranging error of 3m, so that the final positioning precision is influenced; if the atomic clock or other high-performance clock crystal oscillators are used for time synchronization of each anchor node, the cost is too high, and the system complexity is greatly improved.

Disclosure of Invention

aiming at the problems in the prior art, the invention provides a forwarding type indoor positioning method and a forwarding type indoor positioning device, which are used for calculating and obtaining the virtual clock error value of each anchor node by using a forwarding type bidirectional distance measuring method and sending the virtual clock error value to a user terminal for correction, so that the problem of time synchronization among the anchor nodes can be avoided, and high-precision is realizedIndoor positioning applications. The invention provides a forwarding type indoor positioning method, which comprises the following steps: the central processing node i transmits a radio ranging signal and marks the transmission moment in said radio ranging signalWherein i is more than or equal to 1; the anchor node j receives and demodulates the radio ranging signal from the central processing node i and marks the moment of retransmissionthen modulating the signal into a forwarding signal again for forwarding, wherein j is more than or equal to 3; the central processing node i receives and demodulates the forwarding signal from the anchor node j, and records the receiving time of the central processing node i to the forwarding signal of the anchor node jThe central processing node i receives the forwarding signal of the anchor node j according to the central receiving node iThe transmission time of the radio ranging signal transmitted by the central processing node iAnd the distance between the anchor node j and the central processing node i measured in advanceTo calculate an anchor node virtual clock offset Δ T for the anchor node j_ijAnd sending the virtual clock error delta T of the anchor node to a user terminal k_ij(ii) a The user terminal k receives a forwarding signal from the anchor node i and the anchor node virtual clock error delta T from the central processing node i_ijusing said virtual clock difference Δ T_ijand calculating to obtain a distance value rho between the user terminal k and the anchor node i_kj(ii) a According to the distance value rho between the user terminal k and the m anchor nodes j_kjAnd calculating to obtain the position coordinate information of the user terminal k, wherein m is more than or equal to 3.

preferably, the radio ranging signal further includes an ID identification number of the central processing node i; the forwarding signal also comprises an ID identification number of the anchor node j.

preferably, the method for forwarding indoor positioning further includes: pre-measuring the distance between a looking-through anchor node j and a central processing node i using a laser rangefinderAnd the distance between the anchor node j and the central processing node iAnd sending the information to the central processing node i.

Preferably, after the central processing node i receives and demodulates the forwarded signal from the anchor node j, the anchor node virtual clock offset Δ T of the anchor node j is calculated_ijbefore, still include: and the central processing node i screens out the modulated forwarding signals of the anchor node i which are in communication with the central processing node i from the demodulated forwarding signals.

Preferably, the central processing node i is according to the formulaCalculating to obtain virtual clock error delta T of anchor node_ijWhereinFor the time of reception of the forwarded signal of the anchor node j by the central receiving node i,The transmission moment at which the radio ranging signal is transmitted for the central processing node i,For pre-measured anchor node j and central processing nodeDistance between points i, c being 3 × 10⁸M/s.

Preferably, said virtual clock difference Δ T is used_ijAnd calculating to obtain a distance value rho between the user terminal k and the anchor node i_kjthe method comprises the following steps: the user terminal k is according to the formulaCalculating the corrected forwarding time of the anchor node j to the forwarding signalWhereinThe forwarding time, Δ T, of the signaling signal marked for the anchor node j_ijVirtualizing a clock error for the anchor node; according to the formulaCalculating to obtain a distance value rho from the user terminal k to the anchor node j_kjWherein t is_kjFor the moment of reception of the forwarded signal of the anchor node i by the user terminal k,The forwarding time of the forwarding signal is corrected for the anchor node j.

According to a preferred embodiment, the distance values ρ between the user terminal k and the anchor nodes j are determined according to_kjThe step of calculating the position coordinate information of the user terminal k includes: according to the formulaCalculating the abscissa X and the ordinate Y of the position coordinate of the user terminal k, where ρ_kjIs the distance value, X, from the user terminal k to the anchor node j_mIs the abscissa, Y, of the position coordinate of the anchor node j_mis the ordinate, Δ t, of the position coordinate of the anchor node j_kFor clock error, m is the number of anchor nodes i, m is more than or equal to 3, and c is 3 × 10⁸m/s.

according to anotherIn a preferred embodiment, the distance value ρ between the user terminal k and the anchor nodes j is determined according to_kjThe step of calculating the position coordinate information of the user terminal k includes: according to the formulaCalculating the X, Y and Z coordinates of the position coordinates of the user terminal, where rho_kjis the distance value, X, from the user terminal k to the anchor node j_mIs the abscissa, Y, of the position coordinate of the anchor node j_mIs the ordinate, Z, of the position coordinate of the anchor node j_mIs the vertical coordinate of the position coordinate of the anchor node j, m is the number of the anchor nodes i, m is more than or equal to 4, c is 3 multiplied by 10⁸M/s.

The invention also provides a forwarding type indoor positioning device, which comprises: a central processing node i equipped with an atomic clock, configured for transmitting a radio ranging signal and marking the transmission instants in said radio ranging signalWherein i is more than or equal to 1, receiving and demodulating the forwarding signal from the anchor node j, and recording the receiving time of the forwarding signal of the anchor node j by the central processing node iAccording to the receiving time of the forwarding signal of the anchor node j from the central receiving node iThe transmission time of the radio ranging signal transmitted by the central processing node iand the distance between the anchor node j and the central processing node i measured in advanceTo calculate an anchor node virtual clock offset Δ T for the anchor node j_ijAnd to the userthe terminal k sends the virtual clock error delta T of the anchor node_ij(ii) a A plurality of anchor nodes j with radio signal transmitting and receiving functions, wherein the anchor nodes j are configured to receive and demodulate radio ranging signals from the central processing node i and mark forwarding timethen modulating the signal into a forwarding signal again for forwarding, wherein j is more than or equal to 3; a user terminal k with radio signal receiving function, configured to receive the forwarded signal from the anchor node i, and the anchor node virtual clock difference Δ T from the central processing node i_ijUsing said virtual clock difference Δ T_ijAnd calculating to obtain a distance value rho between the user terminal k and the anchor node i_kjAccording to the distance value rho between the user terminal k and a plurality of anchor nodes j_kjAnd calculating to obtain the position coordinate information of the user terminal k.

Preferably, the central processing node i is in communication with all or part of the plurality of anchor nodes j.

By using the forwarding type indoor positioning method and the forwarding type indoor positioning device provided by the invention, the virtual clock error of the anchor node is measured and calibrated in a mode that the central processing node transmits signals and the anchor node forwards signals, and then the user terminal can obtain accurate distance values between the user terminal and each anchor node by using the correction of the virtual clock error of the anchor node, so that indoor high-precision positioning can be realized without time synchronization between the anchor nodes.

Drawings

Fig. 1 shows a flow chart of a method of forwarding indoor positioning according to the present invention;

Fig. 2 illustrates a signal transmission diagram of a repeater type indoor positioning method according to the present invention;

Fig. 3 shows a schematic composition diagram of a repeater indoor positioning device according to the present invention.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

Fig. 1 shows a flowchart of a method for forwarding indoor positioning according to the present invention, and fig. 2 shows a signal transmission diagram of the method for forwarding indoor positioning according to the present invention. Referring to fig. 1 and 2, the present invention provides a forwarding indoor positioning method, which includes the following steps:

Step 101, a central processing node i transmits a radio ranging signal and marks the transmission time in the radio ranging signalWherein i is more than or equal to 1;

The anchor node j receives and demodulates the radio ranging signal from the central processing node i and marks the forwarding time, step 102Then modulating the signal into a forwarding signal again for forwarding, wherein j is more than or equal to 3;

103, the central processing node i receives and demodulates the forwarding signal from the anchor node j, and records the receiving time of the central processing node i to the forwarding signal of the anchor node j

104, the central processing node i receives the forwarding signal of the anchor node j according to the receiving time of the central receiving node iThe transmission time of the radio ranging signal transmitted by the central processing node iAnd the distance between the anchor node j and the central processing node i measured in advanceto calculate an anchor node virtual clock offset Δ T for the anchor node j_ijAnd sending the virtual clock error delta T of the anchor node to a user terminal k_ij；

Step 105, the user terminal k receives the forwarding signal from the anchor node i and the anchor node virtual clock error Δ T from the central processing node i_ijUsing said virtual clock difference Δ T_ijAnd calculating to obtain a distance value rho between the user terminal k and the anchor node i_kj；

106, according to the distance value rho between the user terminal k and a plurality of anchor nodes j_kjAnd calculating to obtain the position coordinate information of the user terminal k.

The forwarding type indoor positioning method provided by the invention firstly obtains the virtual clock error delta T of the anchor node through forwarding type bidirectional distance measurement_ijThen user terminal k receives anchor node virtual clock error delta T_ijCorrecting the forwarding time of the signaling signal forwarded by the anchor node j, thereby calculating the more accurate distance value rho between the user terminal k and the anchor node j_kj. According to the distance value rho between the user terminal k and a plurality of anchor nodes j_kjAnd positioning and resolving the user terminal to obtain the position coordinate information of the user terminal k.

By using the forwarding type indoor positioning method provided by the invention, the virtual clock error of the anchor node is measured and calibrated in a mode that the central processing node transmits signals and the anchor node forwards signals, and then the virtual clock error of the anchor node is used for correction, so that the user terminal can obtain the accurate distance value between the user terminal and each anchor node, and the indoor high-precision positioning can be realized without time synchronization between the anchor nodes.

In order to facilitate the identification of the radio ranging signal transmitted by the central processing node i and the forwarding signal forwarded by the anchor node j, the radio ranging signal also comprises an ID identification number of the central processing node i; the forwarding signal also comprises an ID identification number of the anchor node j.

Preferably, a laser range finder or the like can be used to measure the distance between the anchor node j and the central processing node i in advanceAnd the distance between the anchor node j and the central processing node iSending to the central processing node i for subsequent calculation of an anchor node virtual clock offset Δ T_ij。

Further preferably, after the central processing node i receives and demodulates the forwarded signal from the anchor node j, the anchor node virtual clock offset Δ T of the anchor node j is calculated_ijBefore, still include: and the central processing node i screens out the modulated forwarding signals of the anchor node i which are in communication with the central processing node i from the demodulated forwarding signals. Therefore, forwarding signals of invisible anchor nodes can be screened out, and subsequent calculation operation is carried out only by using effective forwarding signals, so that unnecessary calculation amount is reduced.

In a preferred embodiment, a high precision atomic clock oscillator may be provided in the central processing node so that its marked signal transmission and reception times can be considered accurate. Therefore, the central processing node can calculate the total transmission time T of the signals in the closed loop process of 'transmitting by the central processing node i, receiving by the anchor node j, forwarding by the anchor node j and receiving by the central processing node i' according to the formula (1)_ij：

Wherein the content of the first and second substances,for the time of reception of the forwarded signal of the anchor node j by the central receiving node i,The transmission moment of the radio ranging signal for the central processing node i.

Based on central processing node i measured beforehand using a laser rangefinder or the likeExact geometric distance to each anchor node jKnowing the true time of transmission of the signalThe method comprises the following steps:

Wherein c is 3 × 10⁸m/s is the speed of light.

T_ijandThe difference between the two nodes is mainly caused by the clock error of each anchor node j (because the anchor node is not provided with a high-precision atomic clock crystal oscillator) and the signal forwarding processing delay, and is defined as the virtual clock error delta T of the anchor node_ijAnd has the following components:

Thus, from equations (1) to (3), equation (4) can be obtained:

That is, the central processing node i can calculate the virtual clock offset Δ T of the anchor node according to the above formula (4)_ijWhereinFor the time of reception of the forwarded signal of the anchor node j by the central receiving node i,The transmission moment at which the radio ranging signal is transmitted for the central processing node i,C is the distance between anchor node j and central processing node i measured in advance, and is 3 × 10⁸M/s.

Generally, the central processing node i obtains the virtual clock error Δ T of the anchor node in the calculation_ijAnd then, broadcasting the data for subsequent use by the user terminal.

According to a preferred embodiment, the virtual clock difference Δ T is used_ijand calculating to obtain a distance value rho between the user terminal k and the anchor node i_kjThe method comprises the following steps:

the user terminal k is according to the formulacalculating the corrected forwarding time of the anchor node j to the forwarding signalWhereinThe forwarding time, Δ T, of the signaling signal marked for the anchor node j_ijVirtualizing a clock error for the anchor node;

According to the formulacalculating to obtain a distance value rho from the user terminal k to the anchor node j_kjWherein t is_kjFor the moment of reception of the forwarded signal of the anchor node i by the user terminal k,the forwarding time of the forwarding signal is corrected for the anchor node j.

Specifically, in the above-described procedure, after the anchor node j performs signal transfer, the user terminal k also receives the signal, and marks the reception time t of the signal transferred by the user terminal_kjAnd demodulating the forwarding time of the forwarding signal marked before the anchor node j

At the same time, the user terminal k receives the virtual clock offset Δ T of the anchor node j, which is transmitted later by the central processing node i_ijAnd correcting the forwarding time of the forwarding signal of the anchor node j

On the basis, the user terminal k receives the mark time t by combining the signal thereof_kjand calculating to obtain a distance measurement value rho from the anchor node j to the anchor node j_kj：

It should be noted that the process of receiving the forwarded signal from the anchor node j and receiving the anchor node virtual clock difference value from the central processing node i by the user terminal k is not strictly synchronous (the user terminal k receives the forwarded signal from the anchor node j first and then receives the anchor node virtual clock difference value from the central processing node i after a certain delay), but the influence on the indoor positioning user is negligible. The reason is that the indoor environment is limited in size, the transmission delay of radio signals is short, and the crystal oscillator of the user terminal cannot change greatly in the short time; secondly, because the indoor positioning users are generally low dynamic, the users can not generate large displacement in the time delay process of receiving the anchor node signals and the central processing node signals at the user terminal.

Further preferably, the distance value rho between the user terminal k and a plurality of anchor nodes j is determined according to_kjThe step of calculating the position coordinate information of the user terminal k includes: the abscissa X and the ordinate Y of the position coordinates of the user terminal are calculated according to formula (7),

where ρ is_kjIs the distance value, X, from the user terminal k to the anchor node j_mIs the abscissa, Y, of the position coordinate of the anchor node j_mIs the ordinate, Δ t, of the position coordinate of the anchor node j_kFor clock error, m is the number of anchor nodes i, m is more than or equal to 3, and c is 3 × 10⁸M/s.

Specifically, a distance measurement value ρ is obtained by measuring between the user terminal k and a plurality of anchor nodes j (j ═ 1, 2.. multidot., m)_kjAnd then, simultaneously observing an equation set and positioning and resolving.

For cost reasons, the user terminal is usually not equipped with a high-precision atomic clock crystal oscillator, so that the signal reception marks the time t_kjIt is also not accurate and there is a clock error as with the anchor node. But within a single positioning epoch of short time, the clock error may be considered fixed. That is, the user terminal clock error is measured for each range value ρ_kjThe method is the same, and can be used as a mode for setting error parameters in public, and simultaneously enters the user terminal clock errors into an observation equation set and performs joint solution.

Assuming a two-dimensional indoor positioning application, the known position coordinates of anchor node j (j ═ 1, 2.. multidata., m) are (X)_j，Y_j) The unknown number of the coordinate position of the user terminal is (X, Y), and the unknown number of the clock error of the user terminal is delta t_k. Then, through the measurement of m anchor nodes, a positioning equation set can be obtained in a simultaneous manner:

Expanding Taylor series on the formula (7), and performing Gaussian-Newton linearization iterative solution or Kalman filtering solution to obtain the position coordinates (X, Y) and the clock error delta t of the user terminal_k。

In the two-dimensional positioning process, at least 3 observable anchor nodes are needed because 3 unknown parameters need to be solved, namely m is more than or equal to 3.

It is readily understood that for three-dimensional positioning applications, at least 4 observable anchor nodes are required, i.e., m ≧ 4. Similarly, in the three-dimensional positioning, the abscissa X, ordinate Y and ordinate Z of the position coordinate of the user terminal k can be calculated according to the formula (8),

ρ_kjIs the distance value, X, from the user terminal k to the anchor node j_mIs the abscissa, Y, of the position coordinate of the anchor node j_mIs the ordinate, Z, of the position coordinate of the anchor node j_mIs the vertical coordinate of the position coordinate of the anchor node j, m is the number of the anchor nodes i, m is more than or equal to 4, c is 3 multiplied by 10⁸M/s.

Meanwhile, the present invention also provides a forwarding indoor positioning apparatus, referring to fig. 3, the forwarding indoor positioning apparatus includes: a central processing node i equipped with an atomic clock, a plurality of anchor nodes j having radio signal transmitting and receiving functions, and a user terminal k having a radio signal receiving function,

The central processing node i is configured for transmitting a radio ranging signal and marking the transmission instants in the radio ranging signalwherein i is more than or equal to 1, receiving and demodulating the forwarding signal from the anchor node j, and recording the receiving time of the forwarding signal of the anchor node j by the central processing node iAccording to the receiving time of the forwarding signal of the anchor node j from the central receiving node iThe transmission time of the radio ranging signal transmitted by the central processing node iAnd pre-testingDistance between anchor node j and central processing node i of quantityto calculate an anchor node virtual clock offset Δ T for the anchor node j_ijand sending the virtual clock error delta T of the anchor node to a user terminal k_ij；

The anchor node j is configured for receiving and demodulating radio ranging signals from the central processing node i and marking the moment of retransmissionThen modulating the signal into a forwarding signal again for forwarding, wherein j is more than or equal to 3

The user terminal k is configured to receive the forwarded signal from the anchor node i and the anchor node virtual clock difference Δ T from the central processing node i_ijusing said virtual clock difference Δ T_ijAnd calculating to obtain a distance value rho between the user terminal k and the anchor node i_kjAccording to the distance value rho between the user terminal k and a plurality of anchor nodes j_kjAnd calculating to obtain the position coordinate information of the user terminal k.

The forwarding type indoor positioning device provided by the invention firstly obtains the virtual clock error delta T of the anchor node through forwarding type bidirectional distance measurement_ijthen user terminal k receives anchor node virtual clock error delta T_ijCorrecting the forwarding time of the signaling signal forwarded by the anchor node j, thereby calculating the more accurate distance value rho between the user terminal k and the anchor node j_kj. According to the distance value rho between the user terminal k and a plurality of anchor nodes j_kjand positioning and resolving the user terminal to obtain the position coordinate information of the user terminal k.

Generally, the number of the anchor nodes is at least 3, and the number of the central processing nodes can be 1 or more.

By utilizing the forwarding type indoor positioning device provided by the invention, a small number of central processing nodes with atomic clock crystal oscillators are arranged indoors, the virtual clock error of the anchor nodes is measured and calibrated in a mode that the central processing nodes transmit signals and the anchor nodes forward the signals, and then the virtual clock error of the anchor nodes is utilized for correction, so that the user terminal can obtain the accurate distance value between the user terminal and each anchor node, and the indoor high-precision positioning can be realized without time synchronization between the anchor nodes.

According to a preferred embodiment, the central processing node i is kept in communication with all or part of the plurality of anchor nodes j.

in order to facilitate the identification of the radio ranging signal transmitted by the central processing node i and the forwarding signal forwarded by the anchor node j, the radio ranging signal also comprises an ID identification number of the central processing node i; the forwarding signal also comprises an ID identification number of the anchor node j.

Preferably, a laser range finder or the like can be used to measure the distance between the anchor node j and the central processing node i in advanceand the distance between the anchor node j and the central processing node iSending to the central processing node i for subsequent calculation of an anchor node virtual clock offset Δ T_ij。

Further preferably, after the central processing node i receives and demodulates the forwarded signal from the anchor node j, the anchor node virtual clock offset Δ T of the anchor node j is calculated_ijBefore, the central processing node i may also screen out, from the demodulated forwarded signals, the modulated forwarded signals of the anchor node i that are in communication with the central processing node i. Therefore, forwarding signals of invisible anchor nodes can be screened out, and subsequent calculation operation is carried out only by using effective forwarding signals, so that unnecessary calculation amount is reduced.

In a preferred embodiment, the central processing node i may be according to a formula

Calculating to obtain virtual clock error delta T of anchor node_ijWhereinFor the time of reception of the forwarded signal of the anchor node j by the central processing node i,The transmission moment at which the radio ranging signal is transmitted for the central processing node i,C is the distance between anchor node j and central processing node i measured in advance, and is 3 × 10⁸M/s.

According to a preferred embodiment, the user terminal k may be according to a formulaCalculating the corrected forwarding time of the anchor node j to the forwarding signalWhereinThe forwarding time, Δ T, of the signaling signal marked for the anchor node j_ijVirtualizing a clock error for the anchor node;

According to the formulaCalculating to obtain a distance value rho from the user terminal k to the anchor node j_kjWherein t is_kjFor the moment of reception of the forwarded signal of the anchor node i by the user terminal k,the forwarding time of the forwarding signal is corrected for the anchor node j.

Specifically, in the above steps, after the anchor node j performs signal forwarding,The user terminal k also receives the signal and marks the time t at which the user terminal receives the retransmission signal_kjAnd demodulating the forwarding time of the forwarding signal marked before the anchor node j

At the same time, the user terminal k receives the virtual clock offset Δ T of the anchor node j, which is transmitted later by the central processing node i_ijAnd correcting the forwarding time of the forwarding signal of the anchor node j

On the basis, the user terminal k receives the mark time t by combining the signal thereof_kjAnd calculating to obtain a distance measurement value rho from the anchor node j to the anchor node j_kj：

It should be noted that the process of receiving the forwarded signal from the anchor node j and receiving the anchor node virtual clock difference value from the central processing node i by the user terminal k is not strictly synchronous (the user terminal k receives the forwarded signal from the anchor node j first and then receives the anchor node virtual clock difference value from the central processing node i after a certain delay), but the influence on the indoor positioning user is negligible. The reason is that the indoor environment is limited in size, the transmission delay of radio signals is short, and the crystal oscillator of the user terminal cannot change greatly in the short time; secondly, because the indoor positioning users are generally low dynamic, the users can not generate large displacement in the time delay process of receiving the anchor node signals and the central processing node signals at the user terminal.

Further preferably, the user terminal k may calculate an abscissa X and an ordinate Y of the position coordinate of the user terminal according to formula (7),

Where ρ is_kjIs the distance value, X, from the user terminal k to the anchor node j_mis the abscissa, Y, of the position coordinate of the anchor node j_mIs the ordinate, Δ t, of the position coordinate of the anchor node j_kFor clock error, m is the number of anchor nodes i, m is more than or equal to 3, and c is 3 × 10⁸M/s.

Specifically, a distance measurement value ρ is obtained by measuring between the user terminal k and a plurality of anchor nodes j (j ═ 1, 2.. multidot., m)_kjAnd then, simultaneously observing an equation set and positioning and resolving.

For cost reasons, the user terminal is usually not equipped with a high-precision atomic clock crystal oscillator, so that the signal reception marks the time t_kjIt is also not accurate and there is a clock error as with the anchor node. But within a single positioning epoch of short time, the clock error may be considered fixed. That is, the user terminal clock error is measured for each range value ρ_kjThe method is the same, and can be used as a mode for setting error parameters in public, and simultaneously enters the user terminal clock errors into an observation equation set and performs joint solution.

Assuming a two-dimensional indoor positioning application, the known position coordinates of anchor node j (j ═ 1, 2.. multidata., m) are (X)_j，Y_j) The unknown number of the coordinate position of the user terminal is (X, Y), and the unknown number of the clock error of the user terminal is delta t_k. Then, through the measurement of m anchor nodes, a positioning equation set can be obtained in a simultaneous manner:

Expanding Taylor series on the formula (7), and performing Gaussian-Newton linearization iterative solution or Kalman filtering solution to obtain the position coordinates (X, Y) and the clock error delta t of the user terminal_k。

In the two-dimensional positioning process, at least 3 observable anchor nodes are needed because 3 unknown parameters need to be solved, namely m is more than or equal to 3.

it is readily understood that for three-dimensional positioning applications, at least 4 observable anchor nodes are required, i.e., m ≧ 4. Similarly, in the three-dimensional positioning, the abscissa X, ordinate Y and ordinate Z of the position coordinate of the user terminal k can be calculated according to the formula (8),

ρ_kjIs the distance value, X, from the user terminal k to the anchor node j_mis the abscissa, Y, of the position coordinate of the anchor node j_mIs the ordinate, Z, of the position coordinate of the anchor node j_mIs the vertical coordinate of the position coordinate of the anchor node j, m is the number of the anchor nodes i, m is more than or equal to 4, c is 3 multiplied by 10⁸m/s.

It should be noted that the above description is only a preferred embodiment of the present invention, and it should be understood that various changes and modifications can be made by those skilled in the art without departing from the technical idea of the present invention, and these changes and modifications are included in the protection scope of the present invention.