CN111050393B - UWB positioning system - Google Patents
UWB positioning system Download PDFInfo
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- CN111050393B CN111050393B CN201911180764.2A CN201911180764A CN111050393B CN 111050393 B CN111050393 B CN 111050393B CN 201911180764 A CN201911180764 A CN 201911180764A CN 111050393 B CN111050393 B CN 111050393B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/004—Synchronisation arrangements compensating for timing error of reception due to propagation delay
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/0055—Synchronisation arrangements determining timing error of reception due to propagation delay
- H04W56/0065—Synchronisation arrangements determining timing error of reception due to propagation delay using measurement of signal travel time
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
- H04W64/006—Locating users or terminals or network equipment for network management purposes, e.g. mobility management with additional information processing, e.g. for direction or speed determination
Abstract
The utility model provides a UWB positioning system, includes location label, reference base station, ordinary base station, gateway, positioning engine, reference base station and ordinary base station communication connection, reference base station and ordinary base station are connected with the gateway communication respectively, the gateway is connected with positioning engine communication, be equipped with first sending module and first receiving module on the reference base station, be equipped with second receiving module on the ordinary base station, be equipped with second sending module on the location label, first sending module broadcast beacon frame is to second receiving module, second sending module broadcast location frame is to first receiving module and second receiving module for the location frame arrives reference base station and ordinary base station time difference measurement and calibration. The system realizes frequency synchronization and time synchronization in a wireless mode, does not need to increase a common clock system and lay a synchronous cable, and can effectively reduce the complexity and the design cost of the system.
Description
Technical Field
The invention belongs to the field of wireless communication and positioning, and particularly relates to a UWB positioning system.
Background
The UWB (ultra wide band) positioning technology relies on the instantaneous narrow pulse characteristic of UWB signals, the time of flight (TOF) of the signals is utilized to carry out ranging positioning, and the UWB positioning generally adopts a trilateral positioning method or a time difference positioning method. The time difference positioning method is also called hyperbolic positioning, and compared with a trilateral positioning method, the method only needs to send positioning signals in a single direction, the communication protocol is simple, the expandability of the nodes is higher, and the power consumption is lower. The basic principle of the method is that firstly, the time difference of signals arriving at different reference nodes is measured; then measuring the distance difference between every two nodes based on the time difference, and establishing a hyperbolic equation set; and solving the coordinates of the node to be positioned by solving a quadratic equation.
In order to improve the positioning accuracy, the system needs to accurately measure the arrival time difference of the signals. The traditional technical means is to establish a set of public clock system, distribute a reference clock and a synchronous pulse to all reference nodes through a radio frequency cable, and the radio frequency cable is required to be as long as possible or can be used for delay compensation in advance so as to realize frequency synchronization and time synchronization of all nodes and finally ensure that high-precision time difference information can be obtained. The method has the disadvantages of complex hardware layout, high construction cost and inconvenience for large-scale expansion of the system.
Disclosure of Invention
In order to solve the problem, the UWB positioning system is provided, and the system realizes frequency synchronization and time synchronization in a wireless mode without adding a common clock system and laying a synchronous cable, so that the complexity and the design cost of the system can be effectively reduced.
The utility model provides a UWB positioning system, includes location label, reference base station, ordinary base station, gateway, positioning engine, reference base station and ordinary base station communication connection, reference base station and ordinary base station are connected with the gateway communication respectively, the gateway is connected with positioning engine communication, be equipped with first sending module and first receiving module on the reference base station, be equipped with second receiving module on the ordinary base station, be equipped with second sending module on the location label, first sending module broadcast beacon frame is to second receiving module, second sending module broadcast location frame is to first receiving module and second receiving module for the location frame arrives reference base station and ordinary base station time difference measurement and calibration.
Furthermore, the first sending module broadcasts beacon frames to the second receiving module periodically, and at the same time, the first sending module records and packages the timestamps and frame sequence numbers of the beacon frames broadcasted periodically into a first beacon frame data packet queue, and directly sends the first beacon frame data packet queue to the positioning engine; the second receiving module receives the beacon frame periodically, records and packages the timestamp and the frame serial number of the beacon frame periodically received into a second beacon frame data packet queue, and sends the second beacon frame data packet queue to the positioning engine.
Further, the broadcast period of the beacon frame is not critical, and the broadcast period is not a deterministic delay.
Furthermore, the second sending module broadcasts the positioning frame randomly, the first receiving module and the second receiving module receive the positioning frame, the first receiving module records and packages a frame sequence number and a timestamp of the received positioning frame into a first positioning frame data packet queue, and sends the first positioning frame data packet queue to the positioning engine; and the second receiving module records and packages the frame serial number and the time stamp of the received positioning frame into a second positioning frame data packet queue and sends the second positioning frame data packet queue to the positioning engine, and the positioning engine performs time difference measurement and calibration according to a given calculation method.
Further, the calculation method of the positioning engine comprises the following steps:
a. the positioning engine is based on the base station coordinates,the distance between the reference base station and the common base station is calculated, so that the relative time delay T of the beacon frame propagation is obtaineddx；
b. The positioning engine takes out the data packets with two newly-sent beacon frame serial numbers connected from the first beacon frame data packet queue of the reference base station, and the timestamp of the previous beacon frame is N0And the last beacon frame timestamp is N'0Calculating the difference N between the previous and the next time stamps of the reference base stationspf0＝N'0-N0；
c. In the same step b, the positioning engine takes out the data packets which are sent out newly and are connected with the frame number of the two new tables from the second beacon frame data packet queue of the common base station, and the data packets are respectively N corresponding to the step bxAnd N'xCalculating the difference N between the front and rear time stamps of the common base stationspfx＝N'x-NxThen the actual frequency f of the ordinary base station is calculated according to the following formulaxAnd (3) carrying out calibration:
in the above formula, f0The frequency of the reference base station is calibrated;
d. extracting a positioning frame time stamp information value N received by the reference base station from a first positioning frame data packet queue of the reference base station and a second positioning frame data packet queue of the common base stationtag0And the timestamp information value N of the positioning frame received by the common base stationtagxCalculating the time T of the positioning frame arriving at the reference base station according to the following formula0And time T of arrival at the common base stationx：
e. Calculating the time difference value delta T of the positioning frame reaching each common base station according to a formulax0：
ΔTx0＝Tx-T0
Wherein x is a natural number 1,2,3 … …, and represents different common base station numbers
f. Further using a time difference positioning method using a plurality of sets of delta Tx0＝Tx-T0And calculating the actual coordinate position of the positioning label.
Further, the calculation method of the positioning engine further includes, in step a:
before the measurement of the arrival time difference and the calibration start, the clock frequency of the reference base station is accurately measured and calibrated, and the position coordinates of the reference base station and the common base station are calibrated, so that the relative distance information of the reference base station and the common base station is obtained.
Further, the gateway is a switch or a router, and the gateway is configured to receive the data packets from the reference base station and the normal base station and forward the data packets to the positioning engine. The data transmission between the gateway and the reference base station and the common base station can be realized in a wireless mode or through a network cable.
Further, the positioning engine is a PC server or a resolver, and the positioning engine is configured to receive data packets from each base station, take out corresponding data, perform time difference measurement and calibration, and perform positioning and resolving by using a time difference positioning method.
In order to realize the invention, the method mainly comprises the following steps:
in general, the above technical solutions contemplated by the present invention can achieve the following beneficial effects:
(1) the invention adopts wireless technology to carry out frequency and time synchronization, does not depend on a common reference clock system, does not need to lay a radio frequency synchronous cable, is beneficial to reducing the construction difficulty and reducing the laying cost of the line;
(2) the construction period of hardware arrangement engineering is shortened;
(3) the invention only needs to calibrate the clock of the reference base station, does not make requirements on the common base station, allows the clock between the reference base station and the common base station to have difference, has lower requirements on device screening, and is beneficial to reducing the purchase cost of elements;
(4) the invention adopts a one-way broadcast mode to send the positioning frame and the beacon frame, does not need two-way handshake communication, is beneficial to reducing the communication overhead of nodes, reduces the wireless network congestion and reduces the system power consumption.
(5) The clock calibration method is simple, and the execution efficiency of the positioning engine is high.
Drawings
FIG. 1 is a hardware block diagram of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The utility model provides a UWB positioning system, includes location label (being the label that fig. 1 shows), reference base station, ordinary base station, gateway, positioning engine, reference base station and ordinary base station communication connection, reference base station and ordinary base station respectively with gateway communication connection, the gateway is connected with positioning engine communication, be equipped with first sending module and first receiving module on the reference base station, be equipped with second receiving module on the ordinary base station, be equipped with second sending module on the location label, first sending module broadcast beacon frame to second receiving module, second sending module broadcast location frame to first receiving module and second receiving module for the location frame arrives reference base station and ordinary base station time difference and measures and calibrates.
The first sending module broadcasts beacon frames to the second receiving module periodically, and at the same time, the first sending module records and packs the time stamps and the frame serial numbers of the beacon frames broadcasted periodically into a first beacon frame data packet queue which is directly sent to the positioning engine; the second receiving module is used for recording and packaging the sequence number and the time stamp of the beacon frame received periodically into a second beacon frame data packet queue and sending the second beacon frame data packet queue to the positioning engine, and the frame sequence number accumulated in sequence is used for marking the sending sequence of the beacon frame and is used for the positioning engine to carry out standard sequencing and searching on the received beacon frame data packet queue.
A beacon frame is sent in one period, contains a time stamp and a sequence number and is a data packet. The broadcast period of the beacon frame is not critical, and the broadcast period is not a deterministic delay. The reference base station may transmit on the idle time according to the congestion condition of the current channel.
The second sending module broadcasts the positioning frame as random broadcast, the first receiving module and the second receiving module receive the positioning frame, the first receiving module records and packages the serial number and the time stamp of the received positioning frame into a first positioning frame data packet queue, the second receiving module records and packages the serial number and the time stamp of the received positioning frame into a second positioning frame data packet queue and sends the second positioning frame data packet queue to the positioning engine, and the positioning engine carries out time difference measurement and calibration according to a given calculation method. And marking the sending sequence of the positioning frames, and using the positioning engine to carry out standard sequencing and searching on the received positioning frame data packet queues.
The calculation method of the positioning engine comprises the following steps:
a. the positioning engine calculates the distance between the reference base station and the common base station according to the coordinates of the base station, thereby obtaining the relative time delay T of the beacon frame propagationdx(ii) a The coordinate positions of the reference base station and the common base station can be obtained according to the calibration distance during installation or the measurement and drawing after the installation is finished, and the relative time delay T is calculated according to the coordinate positions and the propagation speed of the electromagnetic wavedxAs shown in fig. 1, in this embodiment, the reference base station is one, and the number of the common base stations is three.
b. The positioning engine takes out the data packets with two newly-sent beacon frame serial numbers connected from the first beacon frame data packet queue of the reference base station, and the timestamp of the previous beacon frame is N0And the last beacon frame timestamp is N'0Calculating the difference N between the previous and the next time stamps of the reference base stationspf0＝N'0-N0；
c. In the same step b, the positioning engine takes out the data packets which are sent out newly and are connected with the frame number of the two new tables from the second beacon frame data packet queue of the common base station, and the data packets are respectively N corresponding to the step bxAnd N'xCalculating the difference N between the front and rear time stamps of the common base stationspfx＝N'x-NxThen the actual frequency f of the ordinary base station is calculated according to the following formulaxAnd (3) carrying out calibration:
in the above formula, f0The frequency of the reference base station is calibrated;
d. extracting a positioning frame receiving time stamp information value N of the reference base station from a first positioning frame data packet queue of the reference base station and a second positioning frame data packet queue of the common base stationtag0Receiving positioning frame time stamp information value N with common base stationtagxCalculating the time T of the positioning frame arriving at the reference base station according to the following formula0And time T of arrival at the common base stationx：
e. Calculating the time difference value delta T of the positioning frame reaching each common base station according to a formulax0：
ΔTx0＝Tx-T0
Wherein x is a natural number 1,2,3, and represents different common base station numbers.
f. Further using a time difference positioning method using a plurality of sets of delta Tx0＝Tx-T0And calculating the actual coordinate position of the positioning label.
The calculation method of the positioning engine further comprises the following steps:
before the measurement of the arrival time difference and the calibration start, the clock frequency of the reference base station is accurately measured and calibrated, and the position coordinates of the reference base station and the common base station are calibrated, so that the relative distance information of the reference base station and the common base station is obtained.
In this embodiment, the gateway is an exchange, and the gateway is configured to receive the data packets from the reference base station and the common base station and forward the data packets to the positioning engine. The positioning engine is a PC server and is used for receiving data packets from each base station, taking out corresponding data, performing time difference measurement and calibration and performing positioning calculation by using a time difference positioning method. In another embodiment, the gateway is a router and the positioning engine is a resolver. The data transmission between the gateway and the reference base station and the common base station can be in a wireless form or through a network cable, in this embodiment, the network cable.
As shown in fig. 1, in this embodiment, the timestamp is recorded by using a high bit width counter, one reference base station is used, and a timestamp N is set0Is 109Time stamp N'0Is 2 x 109，Nspf0Is 109，Ntag0＝3000000187,T0＝6666667290ns，f0Is 300MHz, Td1＝445ns,Td2＝629ns,Td3447ns, there are three common base stations, i.e., x is a natural number 1,2, 3. The first table specifically lists the numerical values of the respective calculation amounts involved in the calculation method of the positioning engine.
In another embodiment, the number of common base stations is four, i.e. x is a natural number 1,2,3, 4. In another embodiment, the number of common base stations is seven, i.e. x is a natural number 1,2,3, 4, 5, 6, 7.
Table values of respective calculated quantities involved in calculation method of positioning engine
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (6)
1. A UWB positioning system comprising: the positioning system comprises a positioning label, a reference base station, a common base station, a gateway and a positioning engine, wherein the reference base station is in communication connection with the common base station, the reference base station and the common base station are respectively in communication connection with the gateway, the gateway is in communication connection with the positioning engine, the reference base station is provided with a first sending module and a first receiving module, the common base station is provided with a second receiving module, the positioning label is provided with a second sending module, the first sending module broadcasts a beacon frame to the second receiving module, and the second sending module broadcasts a positioning frame to the first receiving module and the second receiving module, so that the time difference between the arrival of the positioning frame at the reference base station and the arrival of the common base station can be measured and calibrated;
the positioning engine carries out time difference measurement and calibration according to a given calculation method;
the calculation method of the positioning engine comprises the following steps:
a. the positioning engine calculates the distance between the reference base station and the common base station according to the coordinates of the base station, thereby obtaining the relative time delay T of the beacon frame propagationdx；
b. The positioning engine takes out the data packets with two newly-sent beacon frame serial numbers connected from the first beacon frame data packet queue of the reference base station, and the timestamp of the previous beacon frame is N0And the last beacon frame timestamp is N'0Calculating the difference N between the previous and the next time stamps of the reference base stationspf0＝N′0-N0；
c. In the same step b, the positioning engine takes out the data packets which are sent out newly and are connected with the frame number of the two new tables from the second beacon frame data packet queue of the common base station, and the data packets are respectively N corresponding to the step bxAnd N'xCalculating the difference N between the front and rear time stamps of the common base stationspfx＝N'x-NxThen the actual frequency of the ordinary base station is calculated according to the following formulaRate fxAnd (3) carrying out calibration:
in the above formula, f0The frequency of the reference base station is calibrated;
d. extracting a positioning frame time stamp information value N received by the reference base station from a first positioning frame data packet queue of the reference base station and a second positioning frame data packet queue of the common base stationtag0And the timestamp information value N of the positioning frame received by the common base stationtagxCalculating the time T of the positioning frame arriving at the reference base station according to the following formula0And time T of arrival at the common base stationx：
e. Calculating the time difference value delta T of the positioning frame reaching each common base station according to a formulax0：
ΔTx0＝Tx-T0
Wherein x is natural number 1,2,3 … …, representing different common base station numbers f. adopting time difference positioning method, utilizing multiple groups of delta Tx0＝Tx-T0And calculating the actual coordinate position of the positioning label.
2. The UWB positioning system of claim 1 wherein the first transmitting module broadcasts beacon frames periodically to the second receiving module, and the first transmitting module records and packages the timestamps and frame sequence numbers of the beacon frames broadcast periodically into a first beacon frame data packet queue for direct transmission to the positioning engine; the second receiving module receives the beacon frame periodically, records and packages the timestamp and the frame serial number of the beacon frame periodically received into a second beacon frame data packet queue, and sends the second beacon frame data packet queue to the positioning engine.
3. The UWB positioning system of claim 2, wherein the second sending module broadcasts the positioning frame randomly, the first receiving module and the second receiving module receive the positioning frame, and the first receiving module records and packages a frame sequence number and a timestamp of the received positioning frame into a first positioning frame packet queue and sends the first positioning frame packet queue to the positioning engine; and the second receiving module records and packages the frame serial number and the time stamp of the received positioning frame into a second positioning frame data packet queue and sends the second positioning frame data packet queue to the positioning engine.
4. The UWB positioning system according to claim 1, wherein the calculation method step a of the positioning engine further comprises:
before the measurement of the arrival time difference and the calibration start, the clock frequency of the reference base station is accurately measured and calibrated, and the position coordinates of the reference base station and the common base station are calibrated, so that the relative distance information of the reference base station and the common base station is obtained.
5. The UWB positioning system of claim 1 wherein the gateway is a switch or router, and wherein the gateway is configured to receive data packets from the reference base station and the normal base station and forward the data packets to the positioning engine.
6. The UWB positioning system of claim 1 wherein the positioning engine is a PC server or a resolver.
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| CN111491266A (en) * | 2020-05-16 | 2020-08-04 | 深圳市引力波联科技有限公司 | Time synchronization method for UWB TDOA positioning system base station |
| CN113163485B (en) * | 2021-03-23 | 2022-04-22 | 电子科技大学 | Method for accurately positioning in large-range complex indoor environment |
| CN115134763B (en) * | 2022-02-16 | 2023-10-24 | 浙江利尔达物联网技术有限公司 | Beacon broadcast type UWB ranging method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105579863A (en) * | 2013-09-30 | 2016-05-11 | 高通股份有限公司 | High precision access point to access point synchronization in an indoor position location system |
| CN107635283A (en) * | 2017-09-22 | 2018-01-26 | 华南理工大学 | A kind of indoor high-density mobile tag alignment system and localization method |
| CN109596123A (en) * | 2018-12-07 | 2019-04-09 | 湖北航天飞行器研究所 | A kind of wearable human body temperature type navigation communication means |
| CN109660948A (en) * | 2019-01-14 | 2019-04-19 | 华东师范大学 | A kind of indoor orientation method based on inverse positioning principle |
| CN109819396A (en) * | 2019-01-30 | 2019-05-28 | 北京布科思科技有限公司 | A kind of wireless location method and system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10064148B2 (en) * | 2017-01-20 | 2018-08-28 | M2 Robots, Inc. | Ultra-wide band positioning system |
| KR102130933B1 (en) * | 2017-03-16 | 2020-07-08 | 론프록스 코퍼레이션 | Systems and methods for positioning indoors using wireless positioning nodes |
| CN108366346A (en) * | 2018-04-23 | 2018-08-03 | 京东方科技集团股份有限公司 | A kind of external positioning adapter, communication means, indoor positioning device and method |
-
2019
- 2019-11-27 CN CN201911180764.2A patent/CN111050393B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105579863A (en) * | 2013-09-30 | 2016-05-11 | 高通股份有限公司 | High precision access point to access point synchronization in an indoor position location system |
| CN107635283A (en) * | 2017-09-22 | 2018-01-26 | 华南理工大学 | A kind of indoor high-density mobile tag alignment system and localization method |
| CN109596123A (en) * | 2018-12-07 | 2019-04-09 | 湖北航天飞行器研究所 | A kind of wearable human body temperature type navigation communication means |
| CN109660948A (en) * | 2019-01-14 | 2019-04-19 | 华东师范大学 | A kind of indoor orientation method based on inverse positioning principle |
| CN109819396A (en) * | 2019-01-30 | 2019-05-28 | 北京布科思科技有限公司 | A kind of wireless location method and system |
Non-Patent Citations (1)
| Title |
|---|
| 基于干涉仪测向的电子侦察卫星单星定位精度分析;张紫龙 等;《火力与指挥控制》;20160115;全文 * |
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