CN207460199U - A kind of clock synchronization apparatus of LED visible light indoor positioning - Google Patents

Abstract

The utility model discloses a kind of clock synchronization apparatus of LED visible light indoor positioning, which includes：Clock source block, power line, the transmitter corresponding at least three LED lamps constitute the local area network of single-hop static topological master-slave mode；Clock source is GPS time service benchmark, and clock source uses PLC technology transmission timing information in a manner of multicasting, and the transmitter corresponding to each LED lamp receives timing information by power line, and calculates time offset value and frequency compensation value, by N_squSecondary Phase synchronization, Frequency Synchronization make the time offset value of its local clock progressively reduce trend zero.The utility model realizes that the clock synchronous error of LED visible light indoor positioning is controlled in the range of ns grades.

Description

A kind of clock synchronization apparatus of LED visible light indoor positioning

Technical field

The utility model belongs to wireless self-assembly local area network Clock Synchronization Technology field more particularly to a kind of LED can See the clock synchronization apparatus of light indoor positioning.

Background technology

The clock synchronization apparatus of LED visible light indoor positioning is a kind of local area network of single-hop static topological master-slave mode, by In the diversity of ad-hoc network application environment, the reasons such as temperature change, electromagnetic interference, aging of oscillator, during local in device Clock is inevitably present clocking error with reference clock, and different application environments has different clock synchronization requirements, does not have There is a kind of clock synchronization protocol to be adapted to various environment.

There are mainly two types of the devices for solving master-slave mode local area network clock synchronous error at present, and a kind of is using GPS methods The clock synchronization apparatus of indoor positioning, each node are equipped with the reception system for supporting GPS time stamp, are obtained by taming crystal oscillator and outer The clock synchronous error of portion's GPS time stamp high-precision (ns grades), shortcoming are that each node is equipped with the reception system for supporting GPS time stamp System, cost of investment is very high, and energy consumption is very big, and market is difficult to receive；Another kind is using the NTP methods i.e. indoor positioning of master-slave synchronisation method Clock synchronization apparatus, the time of all nodes is synchronous with main controlled node (time reference node) holding in network, be first Main controlled node is chosen in network, subsequent main controlled node is to each from information of the node multicasting with its temporal, Ge Gecong Node keeps synchronous after the temporal information of main controlled node is obtained with it, and shortcoming is that clock synchronous error is higher (ms grades).

In conclusion problem existing in the prior art is：

In the prior art, although the clock synchronization apparatus of the indoor positioning of GPS methods can obtain ns grades of clock synchronous errors, It is too high because investing, it is difficult to realize；It is same can only to obtain ms grades of clocks for the clock synchronization apparatus technology maturation of the indoor positioning of NTP methods Error is walked, the requirement of LED visible light indoor position accuracy≤0.5 meter can not be met.

Utility model content

In view of the problems of the existing technology, it is same to provide a kind of clock of LED visible light indoor positioning for the utility model Device is walked, realizes and invests reasonable, technical feasibility, clock synchronous error control in ns grades of scopes.

It is GPS time service reference clocks that the utility model only selects clock source first, both ensure that the timing information essence of output It spends for ns grades, and reduces cost of investment；Secondly clock source includes working as using PLC technology by power line multicasting The timing information of preceding timestamp avoids the interference using other electromagnetic waves caused by radio transmission mode, ensure that timing is believed Breath transmission is undistorted；Transmitter corresponding to last each LED lamp is by calculating entrained by the timing information received every time Current time stamp and the time offset value of local clock and frequency compensation value, by N_squSecondary Phase synchronization, Frequency Synchronization, make it The time offset value of local clock progressively reduces trend zero, is handled according to sliding time window mechanism, it is ensured that each LED lamp institute Corresponding transmitter clock synchronous error control is in the range of ns grades.

The utility model is realized in this way a kind of clock synchronization apparatus of LED visible light indoor positioning, the LED can See the clock synchronization apparatus of light indoor positioning as the transmitting unit corresponding to clock source block, power line, at least three LED lamps Into, and form the local area network of single-hop static topological master-slave mode；Transmitter corresponding to each LED lamp includes corresponding transmitting Machine and the LED lamp being electrically connected；Transmitter corresponding to each LED lamp is connected by power line with clock source block It connects；

The clock source uses PLC technology to send the timing information including current time stamp in a manner of multicasting；

Transmitter corresponding to each LED lamp includes determining for current time stamp by what power line reception clock source was sent When information, and calculate the timestamp entrained by each timing information and the time offset value of local clock and frequency compensation value, pass through Cross N_squSecondary Phase synchronization, Frequency Synchronization make the time offset value of transmitter local clock corresponding to each LED lamp progressively Reduction tends to zero, is handled according to sliding time window mechanism, realizes that the clock synchronous error control of LED visible light indoor positioning exists In the range of ns grades.

Further, the clock source block is by GPS clock module, the first main control module, the first power line carrier module and One power module forms；

The GPS clock module connects the first main control module by data cable, and the first main control module is connected again by data cable The first power line carrier module is connect, the first power module is electrically connected respectively with above-mentioned module.

Further, the GPS clock module is mainly by GPS receiver, High-precision O CXO components, local synchronization calibration group Part, error of measurement component, Error processing component, control structure, in-out box composition；The GPS receiver, High-precision O CXO groups Part, local synchronization calibration assemblies, error of measurement component, Error processing component connect control structure, the control structure by printed line In-out box is connected by printed line；

First main control module is made of ARM components；

First power line carrier module is made of power carrier (PLC) component and coupler, the power carrier (PLC) Component connects coupler by printed line；

First power module includes PD21HE551LD-10W DC-DC components, and configures bridge rectifier, common mode filter Ripple inductor；

During the standard that the GPS clock module is sent from GPS antenna or ground control station the acquisition GPS satellite of outdoor erection Between signal tame crystal oscillator, it is made to possess accurate time service benchmark；

First main control module is responsible for being arranged the clock synchronization information of the current time stamp of acquisition, is assembled into number According to serial port protocol command frame, the first power line carrier module of control is chronologically broadcasted；

The processing such as first power line carrier module encodes digital serial port protocol command frame, modulation, by between the set time Every T_ioutThe constantly transmitter multicasting by power line into each LED lamp signal source；

First power module is responsible for the modules into clock source block and provides electric energy.

Further, the clock synchronization section of the transmitter corresponding to each LED lamp is by the second power carrier mould Block, the second main control module, local clock module and second source module composition；

Second power line carrier module connects the second main control module by data cable, and the second main control module passes through data cable Local clock module is reconnected, second source module is electrically connected respectively with above-mentioned module；

Further, second power line carrier module is made of coupler and power carrier (PLC) component；The coupler Power carrier (PLC) component is connected by printed line；

Second main control module is made of ARM main process tasks component, FPGA from processing component；The ARM main process tasks component FPGA is connected from processing component by printed line；

The local clock module includes the RTC real-time clock components of high-performance constant-temperature crystal oscillator OCXO；

The second source module includes PD21HE551LD-10W DC-DC components and configures bridge rectifier, common mode filtering Inductor；

Second power line carrier module such as is responsible for filtered carrier signal is received and demodulated at the processing；

Second main control module is responsible for instruction deciphering, time record, data calculate, information preserves, phase frequency is synchronous, Realize that the transmitter corresponding to each LED lamp passes through N_squSynchronization during secondary clock pair is handled according to sliding time window mechanism, Its time offset value △ T (n) is made progressively to reduce trend zero；

The local clock module is from clock, and temporal information is provided for the transmitter corresponding to LED lamp；

The second source module is responsible for modules in the clock synchronization section into transmitter and provides electric energy.

The advantages of the utility model and good effect are：

The clock synchronization apparatus of LED visible light indoor positioning is a kind of local area network of single-hop static topological master-slave mode, nothing By all basically identical using the robustness, network overhead, convergence rate of its network of which kind of clock synchronization apparatus, the utility model with GPS methods, the indoor positioning of NTP methods clock synchronization apparatus than it is more prominent the advantages of and effect be：First, investment is reasonable, this practicality New Ventures cost is the 10% of GPS methods, with NTP methods it is about the same (except clock source than main controlled node investment be increased slightly in addition to, It is all)；Second is that clock synchronous error is small, the utility model and GPS method clock synchronous errors are all controlled in the range of ns grades, The clock time service precision ＜ 100ns of GPS method transmitters, clock time service precision ＜ 150ns, the NTP methods of the utility model transmitter The clock time service precision ＜ 10ms of transmitter.

Table 1 lists the utility model compared with GPS methods, the performance of NTP subtraction units

Description of the drawings

Fig. 1 is the clock synchronization apparatus schematic diagram for the LED visible light indoor positioning that the utility model embodiment provides.

In Fig. 1：1st, clock source block；2nd, the transmitter corresponding to LED lamp；3rd, power line.

The clock source modular construction schematic diagram that Fig. 2 the utility model embodiments provide.

In figure：1-1, GPS clock module；1-2, the first main control module；1-3, the first power line carrier module；1-4, the first electricity Source module.

Clock synchronization section structure diagram in the transmitter that Fig. 3 the utility model embodiments provide.

In figure：2-1, the second power line carrier module；2-2, the second main control module；2-3, local clock module；2-4, second Power module.

Specific embodiment

The utility model is on the basis of the particularity of LED visible light indoor positioning clock synchronous applications environment is analyzed, knot Different Clock Synchronization Technologies is closed, provides a kind of designing scheme of the clock synchronization apparatus of LED visible light indoor positioning.

In order to make the purpose of the utility model, technical solutions and advantages more clearly understood, below in conjunction with the accompanying drawings and specifically The utility model is further described in embodiment.

As shown in Figure 1a, a kind of clock synchronization apparatus of LED visible light indoor positioning includes clock source block 1, at least three Transmitter 2, power line 3 corresponding to a LED lamp.Transmitting of the clock source block 1 corresponding to by power line 3 and LED lamp Machine 2 is connected, wherein the transmitter 2 corresponding to each LED lamp includes corresponding transmitter and the LED light being electrically connected Tool, the transmitter 2 corresponding to each LED lamp obtain 1 timing information of clock source block by power line 3.

As shown in Figure 1 b, the utility model selects clock on the basis of clock source 1, the transmitter 2 corresponding to each LED lamp Local clock be the local area network that single-hop static topological master-slave mode is formed from clock.Clock source 1 be GPS time service benchmark, clock Source 1 uses PLC technology transmission timing information in a manner of multicasting, and the transmitter 2 corresponding to each LED lamp is logical It crosses power line and receives the timing information that clock source 1 is sent, when calculating the current time stamp entrained by each timing information with local The time offset value of clock and frequency compensation value carry out N to local clock respectively_squSecondary phase, the clock of frequency are synchronous, make at that time Between deviant progressively reduce trend zero.It is handled according to sliding time window mechanism, realizes that the clock of LED visible light indoor positioning is same Control errors are walked in the range of ns grades.

The clock source modular construction that the utility model embodiment provides.

As shown in Fig. 2, the clock source modular construction is by GPS clock module 1-1, the first main control module 1-2, the first electric power Carrier module 1-3, the first power module 1-4 are formed.

GPS clock module 1-1 selects TS3100 series, mainly comprises the following steps：GPS receiver, high-precision Several portions such as OCXO components, local synchronization calibration assemblies, error of measurement component, Error processing left button, control structure, in-out box Point, GPS clock module 1-1 is responsible for receiving external GPS time reference signal and tames crystal oscillator obtaining reference clock, it is made to possess accurately Time service benchmark, exported so as to fulfill high-precision frequency and time signal, be to reach nanosecond time service precision and stabilization at present Spend the most effective mode in the output of 1E12 magnitude frequencies；

First main control module 1-2 is made of ARM components, and the arrangement of current time stamp isochronon synchronizing information will be obtained by, which being responsible for, is Data communication protocol frame, the first power line carrier module 1-3 of control are chronologically broadcasted；

First power line carrier module 1-3 selects ZPLC-10 models, is made of power carrier (PLC) component and coupler, bears Duty encodes digital serial port protocol frame, interweaves, modulating plus synchronization preamble, filtering go out-of-band interference, power amplifier, signal coupling To the power for illumination line of force etc. reason, pass through power line T in regular intervals_ioutConstantly to the corresponding transmitting of each LED lamp Machine multicasting；

What the first power module 1-4 was selected is PD21HE551LD-10W DC-DC models components and configures bridge rectifier, is total to Mould filter inductor is responsible for the modules into clock source block and provides electric energy.

Each module order of connection of clock source block is：GPS clock module 1-1 connects the first main control module 1- by data cable 2, the first main control module 1-2 by data cable reconnect the first power line carrier module 1-3, the first power module 1-4 respectively with it is upper State module electric connection.

The clock synchronization section structure for the transmitter corresponding to LED lamp that the utility model embodiment provides.

As shown in figure 3, the clock synchronization section of the transmitter corresponding to each LED lamp is by the second power carrier Module 2-1, the second main control module 2-2, local clock module 2-3, second source module 2-4 compositions.

Second power line carrier module 2-1 selects ZPLC-10 models, is made of power carrier (PLC) component and coupler, bears Duty by filtered carrier signal it is synchronous, decode, demodulate, deinterleave, be sent into the processing of the second main control module；

Second main control module 2-2 by ARM components be main process task, FPGA components be from processing form, be responsible for instruction understand, when Between record, data calculate, information preserves, phase frequency is synchronous etc., realize that the transmitter corresponding to each LED lamp passes through N_squ Synchronization during secondary clock pair makes its time offset value △ T (n) progressively reduce trend zero；

Local clock module 2-3 selects the RTC real-time clocks component (STM32F2) of high-performance constant-temperature crystal oscillator (OCXO), when Clock precision 60KZH；It is responsible for providing temporal information to the transmitter corresponding to LED lamp；

Second source module 2-4 selects PD21HE551LD-10W DC-DC models components and configures bridge rectifier, common mode filter Ripple inductance is responsible for the modules into transmitter clock synchronization section and provides electric energy.

Each module order of connection of clock synchronization section in transmitter is：Second power line carrier module 2-1 passes through data cable It connects the second main control module 2-2, the second main control module 2-2 to be connected with local clock module 2-3 by data cable, second source mould Block 2-4 is electrically connected respectively with above-mentioned module.

With reference to the clock synchronization principles for the LED visible light indoor positioning that embodiment provides, to the utility model device Realize that the flow of clock synchronous error ＜ 150ns is further described.

The clock source reference clock of the utility model is GPS clock module, and GPS clock module is by receiving external high-precision GPS standard time signal tame crystal oscillator and obtain reference clock, it is made to possess accurate time service benchmark, it is ensured that clock source export Ns grades of time precision.

The power carrier serial port protocol between transmitter corresponding to clock source and each LED lamp is assisted including data communication Negotiation parameter configuration protocol, clock source will include current time stamp T first_1(n), the arrangement of the timing informations such as network IP leads to for data Protocol command frame format is interrogated, as shown in table 1：

1 communications protocol command frame of table

1 byte	1 byte	1 byte	N byte	1 byte
					0xA5	Length (N+1)	D6	Broadcast data	0xA5

Length：D6+ broadcast datas (not including frame head 0xA5, postamble 0xA5, length field)；

D6：Broadcast transmission；

Broadcast data：Including sequence number, current time stamp T_1(n), transmission time interval, network IP, the information such as MAC Address.

Parameter configuration protocol command frame format, as shown in table 2：

2 parameter configuration protocol command frame of table

3 bytes (agreement mark)	1 byte	N byte
			AB BC CD	D1	Verification

D1：Order is locally configured in reading.

The broadcasting command frame that clock source is sent is the transmitter response being not required corresponding to each LED lamp.

Clock source uses PLC technology by power line with Fixed Time Interval T_ioutConstantly to each LED lamp Corresponding transmitter multicasting timing information, often being broadcasted by launch window mechanism once includes current time stamp T_1(n)Periodically The sequence number of oneself is just added 1 by information automatically, the number of broadcast times N of each clock synchronizing cycle_squMore than of transmitter in device It counts or at least above the transmitter number corresponding to the LED lamp of LED visible light indoor positioning.

Transmitter corresponding to each LED lamp can only receive clock source by power line and send out according to the sequence number of oneself The N gone out_squIt is secondary including current time stamp T_1(n)Timing information, and record and receive current time stamp T_1(n)Local zone time T_2(n).Sequence Row number is that the transmitter corresponding to the LED lamp of N is only received from n-th to N_squ+ (N-1) is secondary including current time stamp T_1(n) Timing information, it is ensured that the setting value of the transmitter launch time stamp corresponding to each LED lamp can be arranged according to certain time order Row realize information time sharing transmissions.

Transmitter corresponding to each LED lamp calculates oneself local zone time T_2(n)With clock source current time stamp T_1(n)'s Time offset value and frequency compensation value.

Settling time deviant mathematical formulae △ T (n)=(T_2(n)- T_1(n))-T_dcode- T_dwire,

△ T (n) be transmitter corresponding to LED lamp receive every time the local zone time of clock source current time stamp with it is current The time offset value of timestamp, crystal oscillator synchronous error are distributed as normal distribution, are Ma Er in process △ T (n) at different moments Section's husband's stationary random process；T_2(n)It is the local zone time that transmitter corresponding to LED lamp receives current time stamp every time；T_1(n) It is the current time stamp that clock source is sent every time；T_dcodeCaused prolong is decoded to the timing information frame of reception for transmitter When time span, decoding delay time length it is usually fixed, be to be determined by device performance, can be obtained by test method Delay time length must be decoded；T_dwireFor clock source output timing information frame through the transmission caused by communications to transmitter Delay time length, since the network compartments position of each transmitter to clock source is to immobilize, transmission medium is constant, that is, passes It is defeated apart from constant, therefore can show that timing information frame is transferred to the delay time length caused by transmitter through electric power cable T_dwire, time span is a constant.

Establish frequency compensation value mathematical formulae V_fre(n)=V_fre(n-1)×[(T_1(n)- T_1(n-1))/(T_2(n)- T_2(n-1))], In formula n be n-th Clock Synchronization Procedure, V_fre(n) the frequency compensation value of n-th clock synchronization；V_fre(n-1) the N-1 times clock Synchronous frequency compensation value；T_1(n)It is the current time stamp that clock source n-th is sent；T_1(n-1)It is that clock source is sent for the N-1 times Current time stamp；T_2(n)It is the local zone time of the transmitter n-th reception current time stamp corresponding to LED lamp；T_2(n-1)It is The local zone time of the N-1 times reception current time stamp of transmitter corresponding to LED lamp；

Frequency compensation initial value-V_fre(0) clock source clock frequency f is depended on_masterWith the transmitter corresponding to LED lamp Clock frequency f_slave, obtained by such as following formula：V_fre(0)=2³²×(f_slave/f_master))。

Transmitter corresponding to each LED lamp is to definite every time time offset value △ T (n) and frequency compensation value V_fre (n) preserved, frequency compensation is carried out on the basis of phasor synchronization, realize clock source reference instant and transmitter local moment Phase synchronization and Frequency Synchronization.Transmitter corresponding to each LED lamp passes through N in a period of time_squIt is secondary constantly repeatedly straight Adjustment local zone time deviation is connect, its time offset value △ T (n) is made progressively to reduce trend zero, at sliding time window mechanism Reason, so as to ensure that the transmitter corresponding to each LED lamp has ＜ 150ns time service precisions.

The above is only the preferred embodiment of the utility model only, is not intended to limit the utility model, all at this All any modification, equivalent and improvement made within the spirit and principle of utility model etc., should be included in the utility model Protection domain within.

Claims (1)

1. a kind of clock synchronization apparatus of LED visible light indoor positioning, which is characterized in that the LED visible light indoor positioning Clock synchronization apparatus is made of the transmitter corresponding to clock source block, power line, at least three LED lamps, and forms single-hop The local area network of static topological master-slave mode；Transmitter corresponding to each LED lamp includes corresponding transmitter and is electrically connected therewith The LED lamp connect；Transmitter corresponding to each LED lamp is connected by power line with clock source block；

The clock source block is by GPS clock module, the first main control module, the first power line carrier module and the first power module group Into；

The GPS clock module connects the first main control module by data cable, and the first main control module reconnects the by data cable One power line carrier module, first power module connect GPS clock module, the first main control module, first by conducting wire respectively Power line carrier module；

The GPS clock module is by GPS receiver, High-precision O CXO components, local synchronization calibration assemblies, error of measurement component, error Processing component, control structure, in-out box composition；The GPS receiver, High-precision O CXO components, local synchronization calibration Component, error of measurement component, Error processing component connect control structure by printed line, and the control structure is connected by printed line and inputted Output precision；

First main control module is made of ARM components；

First power line carrier module is made of power carrier component and coupler；The power carrier component is connected by printed line Connect coupler；

First power module includes PD21HE551LD-10W DC-DC components, and configures bridge rectifier, common mode filtering electricity Sensor；

The clock synchronization section of transmitter corresponding to each LED lamp is by the second power line carrier module, the second master control Module, local clock module and second source module composition；

Second power line carrier module connects the second main control module by data cable, and the second main control module is connected again by data cable Connect local clock module, second source module by conducting wire respectively with the second power line carrier module, the second main control module, it is local when Clock module is electrically connected；

Second power line carrier module is made of coupler and power carrier component；The coupler connects electric power by printed line Carrier wave component；

Second main control module is made of ARM main process tasks component, FPGA from processing component；The ARM main process tasks component passes through Printed line connects FPGA from processing component；

The local clock module includes the RTC real-time clock components of high-performance constant-temperature crystal oscillator OCXO；

The second source module includes PD21HE551LD-10W DC-DC components and configures bridge rectifier, common mode filtering inductance Device.