CN105071914A - Digital frequency modulation (FM) broadcast based clock synchronization method and FM broadcast receiver - Google Patents

Abstract

The invention discloses a digital FM broadcast based clock synchronization method. The method comprises that an FM broadcast receiver receives radio data broadcast signals broadcast by an FM broadcast transmitter which is synchronized with standard time; the FM broadcast receiver obtains time synchronization signals in the radio data broadcast signals by demodulation; the FM broadcast receiver obtains local time information of the received time synchronization signals; and according to local position information, the time synchronization signals and local time information of the FM broadcast receiver, time and frequency of a local clock of the FM broadcast receiver are synchronized. The invention also discloses the FM broadcast receiver. Thus, clock of a pseudo-satellite system or a pseudo-satellite similar system is synchronized via FM broadcast, the FM broadcast transmitter transmits standard time to the corresponding FM broadcast receiver via the FM frequency range, and the technical problem that clock synchronization of the pseudo-satellite system or the pseudo-satellite similar system relies on satellite navigation excessively is solved.

Description

Based on clock synchronizing method and the fm broadcast receiver of digital frequency modulation broadcast

Technical field

The present invention relates to wireless navigation technical field, particularly relate to a kind of clock synchronizing method based on digital frequency modulation broadcast and fm broadcast receiver.

Background technology

Along with human society is to the dependence day by day of satellite navigation, existing GPS (Global Position System) (Big Dipper, global positioning system (GlobalPositioningSystem, GPS) etc., being referred to as GPS (Global Position System) (GlobalNavigationSatelliteSystem, GNSS)) the weak shortcoming of signal becomes increasingly conspicuous: under low layer building, jungle and canyon environment, be difficult to location; Substantially cannot locate in the high-rise building of city; Be that name disturbs radionavigational event to get more and more with secret protection, reduce further the daily availability of navigation system; Under war and Antagonistic Environment, radionavigation counter measure is more and more ripe.So the availability of GNSS is queried day by day.

In this context, major country has set about carrying out the work finding GNSS enhancing and backup scenario all in the world, and basic point of departure is all to find and utilize the more navigation sources beyond GNSS, reaches the object strengthening or back up existing GNSS.Wherein, to being most widely used of backing up of satellite navigation is ground pseudo satellite technology.Pseudo satellite, pseudolite (Pseudo-Satellite or Pseudolite is abbreviated as PL) is laid in reflector ground being launched certain framing signal, is usually all to launch the signal being similar to GPS.In theory, in the place that any threat signal is invalid, pseudo satellite, pseudolite can replace satellite and carry out navigator fix, such as, can the scene such as indoor, underground parking and tunnel navigate.

But the basic problem that pseudolite systems or similar pseudolite systems face needs ceaselessly to carry out the clock synchronous between multiple pseudo satellite, pseudolite node.Different from GPS, what pseudo satellite, pseudolite was equipped usually is temperature-compensating crystal oscillator clock, and precision is not high, can produce clock drift, can not precise synchronization with the time reference signal of reference station in the sampling time.But in location model, all pseudo satellite, pseudolites in system must keep synchronous.In prior art, the clock synchronous of real pseudo satellite, pseudolite is generally carried out by navigation satellite, but, if the clock synchronous of pseudo satellite, pseudolite depends on satellite navigation, when satellite navigation was lost efficacy, the clock accuracy of pseudo satellite, pseudolite cannot arrive navigation request and cause pseudo satellite, pseudolite to lose efficacy, and causes the clock of pseudolite systems to be crossed and is synchronized with dependence satellite navigation.

Summary of the invention

Main purpose of the present invention is to provide a kind of clock synchronizing method based on digital frequency modulation broadcast and fm broadcast receiver, and the clock synchronous being intended to solve pseudolite systems or similar pseudolite systems too relies on the technical problem of satellite navigation.

For achieving the above object, a kind of clock synchronizing method based on digital frequency modulation broadcast provided by the invention, the described clock synchronizing method based on digital frequency modulation broadcast comprises:

Fm broadcast receiver receives the Radio Data Broadcast Signal that the frequency-modulated broadcast transmitter synchronous with the standard time is broadcasted;

Described fm broadcast receiver demodulates time synchronizing signal in described Radio Data Broadcast Signal;

Described fm broadcast receiver obtains the local time information that it receives described time synchronizing signal;

Described fm broadcast receiver according to the local position information of self, described time synchronizing signal and local time information, synchronously moment of this fm broadcast receiver local clock and frequency.

Preferably, the far-end temporal information that described time synchronizing signal comprises ranging code, described frequency-modulated broadcast transmitter broadcasts described ranging code and the remote location information of described frequency-modulated broadcast transmitter,

Described fm broadcast receiver is according to described time synchronizing signal, local time information and local position information, and synchronously the moment of this fm broadcast receiver local clock and the step of frequency comprise:

Fm broadcast receiver, according to described local time information, estimates that this fm broadcast receiver receives the evaluation time information of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter;

Fm broadcast receiver, according to described remote location information, local position information, far-end temporal information and evaluation time information, calculates the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock;

Fm broadcast receiver according to described time difference and relative frequency difference, synchronously moment of this fm broadcast receiver local clock and frequency.

Preferably, described fm broadcast receiver obtains its step receiving the local time information of described time synchronizing signal and comprises;

Described fm broadcast receiver generates the local ranging code identical with the pulse signal waveform of the ranging code that described frequency-modulated broadcast transmitter sends;

Described fm broadcast receiver obtains the local clock during impulse waveform phase alignment of the ranging code that the impulse waveform of described local ranging code and described frequency-modulated broadcast transmitter send;

Described fm broadcast receiver, according to described local time information, estimates that this fm broadcast receiver receives the evaluation time information of described ranging code and described fm broadcast receiver comprises with the step of the relative frequency difference between frequency-modulated broadcast transmitter:

Each pulse of the ranging code that described fm broadcast receiver sends according to described frequency-modulated broadcast transmitter and the nominal delay of an one pulse and described local clock, estimate that this fm broadcast receiver receives the estimation clock value of first pulse of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter.

Preferably, described fm broadcast receiver is according to described remote location information, local position information, far-end temporal information and evaluation time information, and the step calculating the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock comprises:

Described fm broadcast receiver, according to described remote location information and local position information, calculates signal from described frequency-modulated broadcast transmitter to the propagation time of fm broadcast receiver;

Described fm broadcast receiver according to described far-end temporal information, estimated time information and transmission time, calculate the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock.

Preferably, described fm broadcast receiver is according to described time difference and relative frequency difference, and the step in the moment and frequency that adjust self clock comprises:

Preferably, described fm broadcast receiver is according to described time difference and relative frequency difference, and the step in the moment and frequency that adjust self clock comprises:

Described fm broadcast receiver, according to the frequency nominal value of described relative frequency difference and described fm broadcast receiver, adjusts the frequency of described fm broadcast receiver clock;

Described fm broadcast receiver, according to the frequency nominal value of described time difference and described fm broadcast receiver, adjusts the moment of described fm broadcast receiver clock.

In addition, for achieving the above object, the present invention also provides a kind of fm broadcast receiver, it is characterized in that, described fm broadcast receiver comprises:

Signal receiving module, for receiving the Radio Data Broadcast Signal that the frequency-modulated broadcast transmitter synchronous with the standard time is broadcasted;

Demodulation module, for demodulating time synchronizing signal in described Radio Data Broadcast Signal;

Local zone time acquisition module, receives the local time information of described time synchronizing signal for obtaining described fm broadcast receiver;

Synchronization module, for the local position information according to self, described time synchronizing signal and local time information, synchronously moment of this fm broadcast receiver local clock and frequency.

Preferably, the far-end temporal information that described time synchronizing signal comprises ranging code, described frequency-modulated broadcast transmitter broadcasts described ranging code and the remote location information of described frequency-modulated broadcast transmitter,

Described synchronization module comprises:

Evaluation unit, for according to described local time information, estimates that this fm broadcast receiver receives the evaluation time information of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter;

Time difference calculating unit, for according to described remote location information, local position information, far-end temporal information and evaluation time information, calculates the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock;

Lock unit, for according to described time difference and relative frequency difference, synchronously moment of this fm broadcast receiver local clock and frequency.

Preferably, described local zone time acquisition module comprises;

Pulse generate unit, for generating the local ranging code identical with the pulse signal waveform of the ranging code that described frequency-modulated broadcast transmitter sends;

Clock value acquiring unit, the local clock during impulse waveform phase alignment of the ranging code that impulse waveform and described frequency-modulated broadcast transmitter for obtaining described local ranging code send;

Described evaluation unit, also for each pulse of ranging code of sending according to described frequency-modulated broadcast transmitter and the nominal delay of its first pulse and described local clock, estimate that this fm broadcast receiver receives the estimation clock value of first pulse of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter.

Preferably, described time difference calculating unit also for:

According to described remote location information and local position information, calculate signal from described frequency-modulated broadcast transmitter to the propagation time of fm broadcast receiver;

According to described far-end temporal information, estimated time information and transmission time, calculate the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock.

Preferably, described lock unit also for:

According to the frequency nominal value of described relative frequency difference and described fm broadcast receiver, adjust the frequency of described fm broadcast receiver clock;

According to the frequency nominal value of described time difference and described fm broadcast receiver, adjust the moment of described fm broadcast receiver clock.

The present invention receives the Radio Data Broadcast Signal in the signal of the frequency-modulated broadcast transmitter broadcast synchronous with the standard time by fm broadcast receiver, then extract the time synchronizing signal in Radio Data Broadcast Signal and obtain local time information and the local position information of this fm broadcast receiver, last according to local position information, time synchronizing signal and local time information, the moment of this fm broadcast receiver local clock synchronous and frequency, thus Radio Data Broadcast Signal is colonized in the vacant resource of traditional FM FM signal, it is far away that data broadcast due to FM frequency range has propagation distance, diffraction and the strong feature of transmittability, thus the present invention realizes the synchronous of clock in pseudolite systems or similar pseudolite systems by FM FM broadcasting, namely by frequency-modulated broadcast transmitter, the standard time is sent to corresponding fm broadcast receiver to complete the synchronous of receiver clock by the data broadcast of FM frequency range, the clock synchronous solving pseudolite systems or similar pseudolite systems too relies on the technical problem of satellite navigation.

Accompanying drawing explanation

Fig. 1 is the structural representation of an embodiment of the clock synchronizing method correspondence system that the present invention is based on digital frequency modulation broadcast;

Fig. 2 is the schematic flow sheet of clock synchronizing method first embodiment that the present invention is based on digital frequency modulation broadcast;

Fig. 3 be FM signal and parasitic digital signal band in Spectrum Relationship figure;

Fig. 4 is the out of band spectrum graph of a relation of FM signal and parasitic digital signal;

Fig. 5 is the signal format of frequency modulation data radio signal D (t) in the clock synchronizing method that the present invention is based on digital frequency modulation broadcast;

Fig. 6 is the performance schematic diagram that basis the present invention is based on the ranging pulse method time of advent in the clock synchronizing method of digital frequency modulation broadcast;

Fig. 7 is the high-level schematic functional block diagram of fm broadcast receiver first embodiment of the present invention.

The realization of the object of the invention, functional characteristics and advantage will in conjunction with the embodiments, are described further with reference to accompanying drawing.

Embodiment

Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.

For a better understanding of the present invention based on the clock synchronizing method of digital frequency modulation broadcast, as shown in Figure 1, the model that the present invention is based on the clock synchronizing method of digital frequency modulation broadcast is used to comprise at least one frequency-modulated broadcast transmitter A0 and multiple fm broadcast receiver (such as three, A1, A2, A3), the clock synchronous flow process of fm broadcast receiver is similar, for convenience of describing, following embodiment is for fm broadcast receiver A1.

The invention provides a kind of clock synchronizing method based on digital frequency modulation broadcast, in the first embodiment of clock synchronizing method that the present invention is based on digital frequency modulation broadcast, with reference to Fig. 2, the clock synchronizing method based on digital frequency modulation broadcast comprises:

Step S10, fm broadcast receiver receives the Radio Data Broadcast Signal that the frequency-modulated broadcast transmitter synchronous with the standard time is broadcasted;

Oneself is time-synchronized to the standard time by frequency-modulated broadcast transmitter A0.In general, the most frequently used standard time is UTC Universal Time Coordinated, synchronous method is the signal utilizing time service type global navigational satellite receiver to receive GLONASS (Global Navigation Satellite System), utilizes time service type global navigational satellite that frequency-modulated broadcast transmitter A0 is time-synchronized to the standard time.When GLONASS (Global Navigation Satellite System) is unavailable, frequency-modulated broadcast transmitter A0 can depend on self clock and carry out work, and now, the time of frequency-modulated broadcast transmitter A0 and standard time can exist error, as long as but error is in admissible scope, still can be considered " being in synchronous regime ".Different application is different to the requirement of admissible scope.Pseudolite systems, time and the UTC Universal Time Coordinated error of usual system frequency-modulated broadcast transmitter A0 are no more than 1 second.

Frequency-modulated broadcast transmitter A0 (hereinafter referred to as transmitter A0) is except the traditional frequency-modulated signals FM (t) of broadcast, also broadcast a kind of Radio Data Broadcast Signal D (t) parasitizing FM broadcasting, this signal broadcasts the far-end temporal information of ranging code and the remote location information of transmitter A0 with ranging code, transmitter A0 simultaneously.Therefore the signal that transmitter A0 launches can be expressed as RF (t)=FM (t)+D (t), wherein whole signals of launching for transmitter A0 of RF (t).Such as, in prior art, be a road analog and digital mixed signal by simulated sound broadcast singal and digital Audio Broadcasting signal syntheses, share a simulated sound broadcasting channel, after Hybrid-modulated Signal is amplified, launch through antenna-feedback system, obtain the radiofrequency signal of predetermined spectrum pattern.In same frequency range simulated sound broadcast singal and digital Audio Broadcasting Signal averaging, transmit simultaneously.

D (t) signal frequency spectrum design with not appreciable impact generally the wireless reception tonequality to existing FM broadcasting for starting point.Fig. 3 gives Whole frequency band spectrum shape, also referred to as form in band, can see that the frequency spectrum B1 of frequency spectrum B2 and FM (t) of D (t) exists overlapping.Fig. 4 gives a kind of non-fully band spectrum form, also referred to as the outer form of band, can see that the frequency spectrum B1 of frequency spectrum B2 and FM (t) of D (t) does not exist overlapping.These two kinds of forms respectively have pluses and minuses, all visible in systems in practice.U.S. HDRadio have employed the outer form of band shown in Fig. 4, and the CDRadio of China then have employed form in the band as Fig. 3.

Usually, the actual data communication function that can realize tens Kbps of D (t) signal.According to the signal format of D (t) of the present invention as shown in Figure 5.According to the present invention, the placement ranging code in our cycle in D (t) signal is data piece between adjacent ranging code.The modulation system of data block is generally OFDM (OFDM) signal.Particularly, D (t) can at time t=[T0+nT _p, T0+nT _p+ T _pn] time interior transmission ranging code c (t-nT), wherein T0 is the initial time of first ranging code, T _pfor the cycle that adjacent ranging code occurs, T _pnfor ranging code continues duration.Ranging code can be pseudo noise code, Gold code etc., and in the present invention, ranging code is not continuous print, but stores data block between adjacent ranging code.

Step S20, described fm broadcast receiver demodulates time synchronizing signal in described Radio Data Broadcast Signal;

From RF (t), demodulation is out by D (t) for fm broadcast receiver A1.If the frequency spectrum of D (t) and frequency-modulated signals FM (t) are not overlapping, then adopt filtering method just can separate.Otherwise the frequency spectrum of D (t) exists overlapping with frequency-modulated signals FM (t), then need to use separation method in band, the separation method as a patent CN201510011206 in-band on-channel digital-analog audio frequency broadcast signal discloses a kind of concrete separation method.Then fm broadcast receiver A1 removes carrier wave to the D (t) after separation, and digitized of going forward side by side sampling obtains D (n).In digital communication, removing carrier wave is routine techniques.

Step S30, described fm broadcast receiver obtains the local time information that it receives described time synchronizing signal;

Fm broadcast receiver A1, when receiving the time synchronizing signal that transmitter A0 sends, records the local time information of fm broadcast receiver A1 at that time.Receiver A1 generates the local ranging code identical with the pulse signal waveform of the ranging code that transmitter A0 sends at local terminal, and receiver A1 obtains the local clock (local time information, this local clock is multiple) during the impulse waveform phase alignment of the ranging code that the impulse waveform of local ranging code and transmitter send.

Step S40, described fm broadcast receiver according to the local position information of self, described time synchronizing signal and local time information, synchronously moment of this fm broadcast receiver local clock and frequency.

The far-end temporal information that time synchronizing signal comprises ranging code, described frequency-modulated broadcast transmitter broadcasts described ranging code and the remote location information of described frequency-modulated broadcast transmitter,

Step S40 comprises:

Step S41, fm broadcast receiver, according to described local time information, estimates that this fm broadcast receiver receives the evaluation time information of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter;

Each pulse of the ranging code that described fm broadcast receiver sends according to described frequency-modulated broadcast transmitter and the nominal delay of an one pulse and described local clock, estimate that this fm broadcast receiver receives the estimation clock value of first pulse of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter.

Fm broadcast receiver A1 generates local ranging code CL (n) identical with transmitter A0 signal c (t) waveform.CL (n) and D (n) are carried out slip related operation.According to the correlation of ranging code, when D (n) and CL (n) phase alignment, now correlated results is maximum, namely obtains a relevant peaks.Suppose that described slip related operation obtains M relevant peaks in arbitrary preset time section Tsel, m relevant peaks is the relevant peaks in this time period corresponding to m ranging code, supposes that local clock corresponding to m relevant peaks is λ _m.Get wherein M to be multiplied by rate (one given percentage) individual maximum relevant peaks and to carry out following valuation computing:

Value to be estimated is:

The initial optimal estimation θ arriving the local moment of (1) first pulse that relevant peaks is corresponding;

(2) the frequency deviation k of transmitter A0 and receiver A1 (this sentences receiver A1 is example) clock.

Known:

Any m pulsion phase is t for the nominal delay of the 1st pulse _m(t ₁=0), have

T＝[t ₁,t ₂,…t _m.....,t _M] ^T

Wherein [] ^trepresenting matrix transposition.

Existing measured value:

M pulse arrival time (local clock) Φ=[λ ₁, λ ₂, λ ₃.. λ _m...., λ _m] ^t, suppose that each Time of arrival noise is ζ=[υ ₁, υ ₂, υ ₃.. υ _m..., υ _m] ^t.

Observational equation:

Local clock corresponding to m relevant peaks is λ _m, namely m observational equation can be expressed as:

λ _m＝(k+1)t _m+θ+υ _m

Or

λ _m-t _m＝kt _m+θ+υ _m

Wherein k is the frequency deviation of transmitting and receiving clock to be asked; θ is the initial optimal estimation arriving the local moment of pulse corresponding to first relevant peaks to be asked, and υ m is m Time of arrival noise

Matrix notation: above-mentioned observational equation can representing matrix form.

Make X=[k, θ] ^t

Then the problems referred to above can be expressed as:

Φ-T＝Γ*X+ζ

Wherein

Namely

$\left[\begin{array}{c}{\mathrm{\λ}}_1-t_1\\ {\mathrm{\λ}}_2-t_2\\ .\\ .\\ .\\ {\mathrm{\λ}}_M-t_M\end{array}\right]=\left[\begin{array}{c}{t}_{1}k+\mathrm{\θ}+{\mathrm{\υ}}_1\\ t_{2}k+\mathrm{\θ}+{\mathrm{\υ}}_2\\ .\\ .\\ .\\ t_{M}k+\mathrm{\θ}+{\mathrm{\υ}}_M\end{array}\right]$

Solve with least square, have:

X＝(Γ ^TΓ) ^-1Γ ^T(Φ-T)

X=[k, θ] ^tin optimal estimation θ and frequency deviation k be desired value.Wherein, θ is required ranging code due in, and frequency deviation k is the relative frequency difference with self clock frequency-modulated broadcast transmitter A0.

It is to be understood that obtain λ _mtechnology be mature technology in the communications, the neighbouring sample point (altogether three sampled points) generally getting that maximum sampled point of relevant peaks and lead-lag calculates.

Step S42, fm broadcast receiver, according to described remote location information, local position information, far-end temporal information and evaluation time information, calculates the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock;

Receiver A1 is according to the remote location information of its local position information and transmitter A0, draw the distance S between receiver A1 and transmitter A0, and fm broadcast signal in atmosphere transmission speed close to the light velocity, thus try to achieve the propagation time of signal spontaneous emission machine A0 to receiver A1; Thus receiver is according to far-end temporal information, information estimated time (i.e. above-mentioned ranging code due in θ) and transmission time, calculates the time difference between receiver A1 and transmitter A0 clock.

Step S43, fm broadcast receiver according to described time difference and relative frequency difference, synchronously moment of this fm broadcast receiver local clock and frequency.

Receiver A1 safeguards local zone time with numeral counter second usually in digital circuit, this digital circuit has a work clock, there is fluctuation in the frequency of this work clock, but frequency nominal value is known (frequency nominal value is set to Fdef), when receiver A1 gives tacit consent to startup, receiver A1 thinks when numeral thinks when counter often increases Fdef that it's one second has past the time second, namely overflows once second.When receiver A1 and transmitter A0 life period difference being detected, by the value (i.e. the moment of receiver A1) of timer second, the minimizing time difference is multiplied by frequency nominal value accordingly; When relative frequency difference (i.e. frequency deviation k) being detected, the work clock actual frequency of this digital circuit is adjusted to Fdef/ (1+K).

In the present embodiment, fm broadcast receiver receives the Radio Data Broadcast Signal in the signal of the frequency-modulated broadcast transmitter broadcast synchronous with the standard time, then extract the time synchronizing signal in Radio Data Broadcast Signal and obtain local time information and the local position information of this fm broadcast receiver, last according to local position information, time synchronizing signal and local time information, the moment of this fm broadcast receiver local clock synchronous and frequency, thus Radio Data Broadcast Signal is colonized in the vacant resource of traditional FM FM signal, it is far away that data broadcast due to FM frequency range has propagation distance, diffraction and the strong feature of transmittability, thus the present invention realizes the synchronous of clock in pseudolite systems or similar pseudolite systems by FM FM broadcasting, namely by frequency-modulated broadcast transmitter, the standard time is sent to corresponding fm broadcast receiver to complete the synchronous of receiver clock by the data broadcast of FM frequency range, the clock synchronous solving pseudolite systems or similar pseudolite systems too relies on the technical problem of satellite navigation.

Further, on the basis of clock synchronizing method first embodiment that the present invention is based on digital frequency modulation broadcast, propose the second embodiment of the clock synchronizing method based on digital frequency modulation broadcast, in a second embodiment, step S30 comprises:

Step S31, described fm broadcast receiver generates the local ranging code identical with the pulse signal waveform of the ranging code that described frequency-modulated broadcast transmitter sends;

Step S32, described fm broadcast receiver obtains the local clock during impulse waveform phase alignment of the ranging code that the impulse waveform of described local ranging code and described frequency-modulated broadcast transmitter send;

Fm broadcast receiver A1 generates local ranging code CL (n) identical with transmitter A0 signal c (t) waveform.CL (n) and D (n) are carried out slip related operation.According to the correlation of ranging code, when D (n) and CL (n) phase alignment, now correlated results is maximum, namely obtains a relevant peaks, records the local clock (current moment) when each relevant peaks produces.

Step S41 comprises:

Step S411, each pulse of the ranging code that described fm broadcast receiver sends according to described frequency-modulated broadcast transmitter and the nominal delay of an one pulse and described local clock, estimate that this fm broadcast receiver receives the estimation clock value of first pulse of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter.

Fm broadcast receiver A1 generates local ranging code CL (n) identical with transmitter A0 signal c (t) waveform.CL (n) and D (n) are carried out slip related operation.According to the correlation of ranging code, when D (n) and CL (n) phase alignment, now correlated results is maximum, namely obtains a relevant peaks.Suppose that described slip related operation obtains M relevant peaks in arbitrary preset time section Tsel, m relevant peaks is the relevant peaks in this time period corresponding to m ranging code, supposes that local clock corresponding to m relevant peaks is λ _m.Get wherein M to be multiplied by rate (one given percentage) individual maximum relevant peaks and to carry out following valuation computing:

Value to be estimated is:

The initial optimal estimation θ arriving the local moment of (1) first pulse that relevant peaks is corresponding;

(2) the frequency deviation k of transmitter A0 and receiver A1 (this sentences receiver A1 is example) clock.

Known:

Any m pulsion phase is t for the nominal delay of the 1st pulse _m(t ₁=0), have

T＝[t ₁,t ₂,…t _m.....,t _M] ^T

Wherein [] ^trepresenting matrix transposition.

Existing measured value:

M pulse arrival time (local clock) Φ=[λ ₁, λ ₂, λ ₃.. λ _m...., λ _m] ^t, suppose that each Time of arrival noise is ζ=[υ ₁, υ ₂, υ ₃.. υ _m..., υ _m] ^t.

Observational equation:

Local clock corresponding to m relevant peaks is λ _m, namely m observational equation can be expressed as:

λ _m＝(k+1)t _m+θ+υ _m

Or

λ _m-t _m＝kt _m+θ+υ _m

Wherein k is the frequency deviation of transmitting and receiving clock to be asked; θ is the initial optimal estimation arriving the local moment of pulse corresponding to first relevant peaks to be asked, and υ m is m Time of arrival noise

Matrix notation: above-mentioned observational equation can representing matrix form.

Make X=[k, θ] ^t

Then the problems referred to above can be expressed as:

Φ-T＝Γ*X+ζ

Wherein

Namely

$\left[\begin{array}{c}{\mathrm{\λ}}_1-t_1\\ {\mathrm{\λ}}_2-t_2\\ .\\ .\\ .\\ {\mathrm{\λ}}_M-t_M\end{array}\right]=\left[\begin{array}{c}{t}_{1}k+\mathrm{\θ}+{\mathrm{\υ}}_1\\ t_{2}k+\mathrm{\θ}+{\mathrm{\υ}}_2\\ .\\ .\\ .\\ t_{M}k+\mathrm{\θ}+{\mathrm{\υ}}_M\end{array}\right]$

Solve with least square, have:

X＝(Γ ^TΓ) ^-1Γ ^T(Φ-T)

X=[k, θ] ^tin optimal estimation θ and frequency deviation k be desired value.Wherein, θ is required ranging code due in, and frequency deviation k is the relative frequency difference with self clock frequency-modulated broadcast transmitter A0.It is to be understood that obtain λ _mtechnology be mature technology in the communications, the neighbouring sample point (altogether three sampled points) generally getting that maximum sampled point of relevant peaks and lead-lag calculates.

In existing airmanship (such as GPS navigation, Beidou navigation etc.), bandwidth generally reaches more than 2Mhz, and ranging code is continuous print, the code phase resolution that just can reach sub-meter grade is followed the tracks of by code phase, and ranging code is not continuous print in the present invention, data block is stored between adjacent ranging code, the bandwidth of D (t) signal only has hundreds of KHz (narrow bandwidth), the sampling clock of usual employing 1Msps goes sampling, now the resolution of clock only has 1us, and such synchronous error is obviously too large.

In a second embodiment, by the initial optimal estimation θ arriving the local moment comprehensively using multiple relevant peaks to estimate pulse corresponding to first relevant peaks, and the frequency deviation k of transmitter A0 and receiver A1 (this sentences receiver A1 is example) clock, thus local clock moment of receiver A1 and frequency are adjusted, with synchronous with transmitter A0, achieve and achieve high-precision time synchronized when the lower sampling clock of frequency ratio and narrow band signal, with reference to Fig. 6, Fig. 6 gives use 48 pulses, pulse utilization rate rate is respectively 0.6, 0.8, optimal estimation θ mean square error when 1, usually 10 nanosecond orders can be reached through measuring synchronous precision, wherein, abscissa Eb/N0 in Fig. 6 is the energy of every Bit data of the radio signal received and the ratio of Carrier To Noise Power Density, it is the universal method representing the radio signal quality received in this area, the ordinate RMSE of Fig. 6 is the root-mean-square error between the estimated value of θ and actual value, and unit is nanosecond, is the universal method representing valuation quality in this area.

On the basis of clock synchronizing method second embodiment that the present invention is based on digital frequency modulation broadcast, propose the 3rd embodiment of the clock synchronizing method based on digital frequency modulation broadcast, in the third embodiment, step S42 comprises:

Step S421, described fm broadcast receiver, according to described remote location information and local position information, calculates the propagation time of signal at described frequency-modulated broadcast transmitter and fm broadcast receiver;

If the remote location information of transmitter A0 is P _tx=[x _tx, y _tx, z _tx], the local position information of receiver A1 is P _rx=[x _rx, y _rx, z _rx], calculate the propagation time T of signal spontaneous emission machine A0 to receiver A1 _prop=| P _tx-P _rx|/C, wherein C is the light velocity.

Step S422, described fm broadcast receiver according to described far-end temporal information, estimated time information and transmission time, calculate the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock.

Far-end temporal information is included in Preset Time (as T _selin) first the transmitter A0 time that pulse is corresponding be θ _tx, the local zone time that receiver receives first pulse corresponding is θ _rxthe time difference T of=θ, transmitter A0 and receiver A1 clock _e=θ _tx+ Tprop-θ _rx.

In the present embodiment, by calculating the signal propagation time between the transmitter and receiver according to the local position information of receiver and the remote location information of transmitter, again according to the information and transmission time estimated time of the far-end temporal information of transmitter, receiver, calculate the time difference between receiver clock and transmitter clock, obtain the time difference between receiver clock and transmitter clock with a kind of simple account form.

On the basis of clock synchronizing method the 3rd embodiment that the present invention is based on digital frequency modulation broadcast, the 4th embodiment of the clock synchronizing method based on digital frequency modulation broadcast is proposed, in the fourth embodiment,

Step 43 comprises:

Step S431, described fm broadcast receiver, according to the frequency nominal value of described relative frequency difference and described fm broadcast receiver, adjusts the frequency of described fm broadcast receiver clock;

Step S432, described fm broadcast receiver, according to the frequency nominal value of described time difference and described fm broadcast receiver, adjusts the moment of described fm broadcast receiver clock.

In the present embodiment, fm broadcast receiver safeguards local zone time with numeral counter second usually in digital circuit, and this digital circuit has a work clock, and its frequency exists fluctuation, but frequency nominal value (unit: MHz) is known, setting this frequency nominal value is Fdef.Receiver A1 gives tacit consent to when starting, if the timer digital second of receiver A1 often increases Fdef, it's one second has past the time, namely overflows once second.When transmitter A0 and receiver A1 life period difference T being detected _etime, then by second counter value reduce { T accordingly _e* Fdef} (needs round up, and also may be negative values).When frequency deviation k being detected, illustrate that a work clock actual frequency of this digital circuit is Fdef/ (1+k), therefore fm broadcast receiver A1 should adjust a second overflow mechanism, becomes and thinks that it's one second has past the time when numeral counter second reaches when frequency nominal value adds Fdef/ (1+K) (needs round up).

The invention provides a kind of fm broadcast receiver, in the first embodiment of fm broadcast receiver of the present invention, with reference to Fig. 7, fm broadcast receiver comprises:

Signal receiving module 10, for receiving the Radio Data Broadcast Signal that the frequency-modulated broadcast transmitter synchronous with the standard time is broadcasted;

Oneself is time-synchronized to the standard time by frequency-modulated broadcast transmitter A0.In general, the most frequently used standard time is UTC Universal Time Coordinated, synchronous method is the signal utilizing time service type global navigational satellite receiver to receive GLONASS (Global Navigation Satellite System), utilizes time service type global navigational satellite that frequency-modulated broadcast transmitter A0 is time-synchronized to the standard time.When GLONASS (Global Navigation Satellite System) is unavailable, frequency-modulated broadcast transmitter A0 can depend on self clock and carry out work, and now, the time of frequency-modulated broadcast transmitter A0 and standard time can exist error, as long as but error is in admissible scope, still can be considered " being in synchronous regime ".Different application is different to the requirement of admissible scope.Pseudolite systems, time and the UTC Universal Time Coordinated error of usual system frequency-modulated broadcast transmitter A0 are no more than 1 second.

Frequency-modulated broadcast transmitter A0 (hereinafter referred to as transmitter A0) is except the traditional frequency-modulated signals FM (t) of broadcast, also broadcast a kind of Radio Data Broadcast Signal D (t) parasitizing FM broadcasting, this signal broadcasts the far-end temporal information of ranging code and the remote location information of transmitter A0 with ranging code, transmitter A0 simultaneously.Therefore the signal that transmitter A0 launches can be expressed as RF (t)=FM (t)+D (t), wherein whole signals of launching for transmitter A0 of RF (t).Such as, in prior art, be a road analog and digital mixed signal by simulated sound broadcast singal and digital Audio Broadcasting signal syntheses, share a simulated sound broadcasting channel, after Hybrid-modulated Signal is amplified, launch through antenna-feedback system, obtain the radiofrequency signal of predetermined spectrum pattern.In same frequency range simulated sound broadcast singal and digital Audio Broadcasting Signal averaging, transmit simultaneously.

D (t) signal frequency spectrum design with not appreciable impact generally the wireless reception tonequality to existing FM broadcasting for starting point.Fig. 3 gives Whole frequency band spectrum shape, also referred to as form in band, can see that the frequency spectrum B1 of frequency spectrum B2 and FM (t) of D (t) exists overlapping.Fig. 4 gives a kind of non-fully band spectrum form, also referred to as the outer form of band, can see that the frequency spectrum B1 of frequency spectrum B2 and FM (t) of D (t) does not exist overlapping.These two kinds of forms respectively have pluses and minuses, all visible in systems in practice.U.S. HDRadio have employed the outer form of band shown in Fig. 4, and the CDRadio of China then have employed form in the band as Fig. 3.

Usually, the actual data communication function that can realize tens Kbps of D (t) signal.According to the signal format of D (t) of the present invention as shown in Figure 5.According to the present invention, the placement ranging code in our cycle in D (t) signal is data piece between adjacent ranging code.The modulation system of data block is generally OFDM (OFDM) signal.Particularly, D (t) can at time t=[T0+nT _p, T0+nT _p+ T _pn] time interior transmission ranging code c (t-nT), wherein T0 is the initial time of first ranging code, T _pfor the cycle that adjacent ranging code occurs, T _pnfor ranging code continues duration.Ranging code can be pseudo noise code, Gold code etc., and in the present invention, ranging code is not continuous print, but stores data block between adjacent ranging code.

Demodulation module 20, for demodulating time synchronizing signal in described Radio Data Broadcast Signal;

From RF (t), demodulation is out by D (t) for the demodulation module 20 of fm broadcast receiver A1.If the frequency spectrum of D (t) and frequency-modulated signals FM (t) are not overlapping, then adopt filtering method just can separate.Otherwise the frequency spectrum of D (t) exists overlapping with frequency-modulated signals FM (t), then need to use separation method in band, the separation method as a patent CN201510011206 in-band on-channel digital-analog audio frequency broadcast signal discloses a kind of concrete separation method.Then the demodulation module 20 of fm broadcast receiver A1 removes carrier wave to the D (t) after separation, and digitized of going forward side by side sampling obtains D (n).In digital communication, removing carrier wave is routine techniques.

Local zone time acquisition module 30, receives the local time information of described time synchronizing signal for obtaining described fm broadcast receiver;

The local zone time acquisition module 30 of fm broadcast receiver A1, when receiving the time synchronizing signal that transmitter A0 sends, records the local time information of fm broadcast receiver A1 at that time.Receiver A1 generates the local ranging code identical with the pulse signal waveform of the ranging code that transmitter A0 sends at local terminal, and receiver A1 obtains the local clock (local time information, this local clock is multiple) during the impulse waveform phase alignment of the ranging code that the impulse waveform of local ranging code and transmitter send.

Synchronization module 40, for the local position information according to self, described time synchronizing signal and local time information, synchronously moment of this fm broadcast receiver local clock and frequency.

The far-end temporal information that time synchronizing signal comprises ranging code, described frequency-modulated broadcast transmitter broadcasts described ranging code and the remote location information of described frequency-modulated broadcast transmitter,

Described synchronization module 40 comprises:

Evaluation unit 41, for according to described local time information, estimates that this fm broadcast receiver receives the evaluation time information of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter;

Each pulse of the ranging code that described fm broadcast receiver sends according to described frequency-modulated broadcast transmitter and the nominal delay of an one pulse and described local clock, estimate that this fm broadcast receiver receives the estimation clock value of first pulse of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter.

Fm broadcast receiver A1 generates local ranging code CL (n) identical with transmitter A0 signal c (t) waveform.CL (n) and D (n) are carried out slip related operation.According to the correlation of ranging code, when D (n) and CL (n) phase alignment, now correlated results is maximum, namely obtains a relevant peaks.Suppose that described slip related operation obtains M relevant peaks in arbitrary preset time section Tsel, m relevant peaks is the relevant peaks in this time period corresponding to m ranging code, supposes that local clock corresponding to m relevant peaks is λ _m.Get wherein M to be multiplied by rate (one given percentage) individual maximum relevant peaks and to carry out following valuation computing:

Value to be estimated is:

The initial optimal estimation θ arriving the local moment of (1) first pulse that relevant peaks is corresponding;

(2) the frequency deviation k of transmitter A0 and receiver A1 (this sentences receiver A1 is example) clock.

Known:

Any m pulsion phase is t for the nominal delay of the 1st pulse _m(t ₁=0), have

T＝[t ₁,t ₂,…t _m.....,t _M] ^T

Wherein [] ^trepresenting matrix transposition.

Existing measured value:

M pulse arrival time (local clock) Φ=[λ ₁, λ ₂, λ ₃.. λ _m...., λ _m] ^t, suppose that each Time of arrival noise is ζ=[υ ₁, υ ₂, υ ₃.. υ _m..., υ _m] ^t.

Observational equation:

Local clock corresponding to m relevant peaks is λ _m, namely m observational equation can be expressed as:

λ _m＝(k+1)t _m+θ+υ _m

Or

λ _m-t _m＝kt _m+θ+υ _m

Wherein k is the frequency deviation of transmitting and receiving clock to be asked; θ is the initial optimal estimation arriving the local moment of pulse corresponding to first relevant peaks to be asked, and υ m is m Time of arrival noise

Matrix notation: above-mentioned observational equation can representing matrix form.

Make X=[k, θ] ^t

Then the problems referred to above can be expressed as:

Φ-T＝Γ*X+ζ

Wherein

Namely

$\left[\begin{array}{c}{\mathrm{\λ}}_1-t_1\\ {\mathrm{\λ}}_2-t_2\\ .\\ .\\ .\\ {\mathrm{\λ}}_M-t_M\end{array}\right]=\left[\begin{array}{c}{t}_{1}k+\mathrm{\θ}+{\mathrm{\υ}}_1\\ t_{2}k+\mathrm{\θ}+{\mathrm{\υ}}_2\\ .\\ .\\ .\\ t_{M}k+\mathrm{\θ}+{\mathrm{\υ}}_M\end{array}\right]$

Solve with least square, have:

X＝(Γ ^TΓ) ^-1Γ ^T(Φ-T)

X=[k, θ] ^tin optimal estimation θ and frequency deviation k be desired value.Wherein, θ is required ranging code due in, and frequency deviation k is the relative frequency difference with self clock frequency-modulated broadcast transmitter A0.

It is to be understood that obtain λ _mtechnology be mature technology in the communications, the neighbouring sample point (altogether three sampled points) generally getting that maximum sampled point of relevant peaks and lead-lag calculates.

Time difference calculating unit 42, for according to described remote location information, local position information, far-end temporal information and evaluation time information, calculates the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock;

The time difference calculating unit 42 of receiver A1 is according to the remote location information of its local position information and transmitter A0, draw the distance S between receiver A1 and transmitter A0, and fm broadcast signal in atmosphere transmission speed close to the light velocity, thus try to achieve the propagation time of signal spontaneous emission machine A0 to receiver A1; Thus receiver is according to far-end temporal information, information estimated time (i.e. above-mentioned ranging code due in θ) and transmission time, calculates the time difference between receiver A1 and transmitter A0 clock.

Lock unit 43, for according to described time difference and relative frequency difference, synchronously moment of this fm broadcast receiver local clock and frequency.

The lock unit 43 of receiver A1 safeguards local zone time with numeral counter second usually in digital circuit, this digital circuit has a work clock, there is fluctuation in the frequency of this work clock, but frequency nominal value is known (frequency nominal value is set to Fdef), when receiver A1 gives tacit consent to startup, receiver A1 thinks when numeral thinks when counter often increases Fdef that it's one second has past the time second, namely overflows once second.When receiver A1 and transmitter A0 life period difference being detected, by the value (i.e. the moment of receiver A1) of timer second, the minimizing time difference is multiplied by frequency nominal value accordingly; When relative frequency difference (i.e. frequency deviation k) being detected, the work clock actual frequency of this digital circuit is adjusted to Fdef/ (1+K).

In the present embodiment, the signal receiving module 10 of fm broadcast receiver receives the Radio Data Broadcast Signal in the signal of the frequency-modulated broadcast transmitter broadcast synchronous with the standard time, then demodulation module 20 extracts local time information and the local position information that time synchronizing signal in Radio Data Broadcast Signal and local zone time acquisition module 30 obtain this fm broadcast receiver, last synchronization module 40 is according to local position information, time synchronizing signal and local time information, the moment of this fm broadcast receiver local clock synchronous and frequency, thus Radio Data Broadcast Signal is colonized in the vacant resource of traditional FM FM signal, it is far away that data broadcast due to FM frequency range has propagation distance, diffraction and the strong feature of transmittability, thus the present invention realizes the synchronous of clock in pseudolite systems or similar pseudolite systems by FM FM broadcasting, namely by frequency-modulated broadcast transmitter, the standard time is sent to corresponding fm broadcast receiver to complete the synchronous of receiver clock by the data broadcast of FM frequency range, the clock synchronous solving pseudolite systems or similar pseudolite systems too relies on the technical problem of satellite navigation.

Further, on the basis of fm broadcast receiver first embodiment of the present invention, propose the second embodiment of fm broadcast receiver, in a second embodiment, described local zone time acquisition module 30 comprises;

Pulse generate unit 31, for generating the local ranging code identical with the pulse signal waveform of the ranging code that described frequency-modulated broadcast transmitter sends;

Clock value acquiring unit 32, the local clock during impulse waveform phase alignment of the ranging code that impulse waveform and described frequency-modulated broadcast transmitter for obtaining described local ranging code send;

The pulse generate unit 31 of fm broadcast receiver A1 generates local ranging code CL (n) identical with transmitter A0 signal c (t) waveform.CL (n) and D (n) are carried out slip related operation by clock value acquiring unit 32.According to the correlation of ranging code, when D (n) and CL (n) phase alignment, now correlated results is maximum, namely obtains a relevant peaks, records the local clock (current moment) when each relevant peaks produces.

Described evaluation unit 41, also for each pulse of ranging code of sending according to described frequency-modulated broadcast transmitter and the nominal delay of its first pulse and described local clock, estimate that this fm broadcast receiver receives the estimation clock value of first pulse of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter.

Fm broadcast receiver A1 generates local ranging code CL (n) identical with transmitter A0 signal c (t) waveform.CL (n) and D (n) are carried out slip related operation.Evaluation unit 41 is according to the correlation of ranging code, and when D (n) and CL (n) phase alignment, now correlated results is maximum, namely obtains a relevant peaks.Suppose that described slip related operation obtains M relevant peaks in arbitrary preset time section Tsel, m relevant peaks is the relevant peaks in this time period corresponding to m ranging code, supposes that local clock corresponding to m relevant peaks is λ _m.Get wherein M to be multiplied by rate (one given percentage) individual maximum relevant peaks and to carry out following valuation computing:

Value to be estimated is:

The initial optimal estimation θ arriving the local moment of (1) first pulse that relevant peaks is corresponding;

(2) the frequency deviation k of transmitter A0 and receiver A1 (this sentences receiver A1 is example) clock.

Known:

Any m pulsion phase is t for the nominal delay of the 1st pulse _m(t ₁=0), have

T＝[t ₁,t ₂,…t _m.....,t _M] ^T

Wherein [] ^trepresenting matrix transposition.

Existing measured value:

M pulse arrival time (local clock) Φ=[λ ₁, λ ₂, λ ₃.. λ _m...., λ _m] ^t, suppose that each Time of arrival noise is ζ=[υ ₁, υ ₂, υ ₃.. υ _m..., υ _m] ^t.

Observational equation:

Local clock corresponding to m relevant peaks is λ _m, namely m observational equation can be expressed as:

λ _m＝(k+1)t _m+θ+υ _m

Or

λ _m-t _m＝kt _m+θ+υ _m

Wherein k is the frequency deviation of transmitting and receiving clock to be asked; θ is the initial optimal estimation arriving the local moment of pulse corresponding to first relevant peaks to be asked, and υ m is m Time of arrival noise

Matrix notation: above-mentioned observational equation can representing matrix form.

Make X=[k, θ] ^t

Then the problems referred to above can be expressed as:

Φ-T＝Γ*X+ζ

Wherein

Namely

$\left[\begin{array}{c}{\mathrm{\λ}}_1-t_1\\ {\mathrm{\λ}}_2-t_2\\ .\\ .\\ .\\ {\mathrm{\λ}}_M-t_M\end{array}\right]=\left[\begin{array}{c}{t}_{1}k+\mathrm{\θ}+{\mathrm{\υ}}_1\\ t_{2}k+\mathrm{\θ}+{\mathrm{\υ}}_2\\ .\\ .\\ .\\ t_{M}k+\mathrm{\θ}+{\mathrm{\υ}}_M\end{array}\right]$

Solve with least square, have:

X＝(Γ ^TΓ) ^-1Γ ^T(Φ-T)

X=[k, θ] ^tin optimal estimation θ and frequency deviation k be desired value.Wherein, θ is required ranging code due in, and frequency deviation k is the relative frequency difference with self clock frequency-modulated broadcast transmitter A0.It is to be understood that obtain λ _mtechnology be mature technology in the communications, the neighbouring sample point (altogether three sampled points) generally getting that maximum sampled point of relevant peaks and lead-lag calculates.

In existing airmanship (such as GPS navigation, Beidou navigation etc.), bandwidth generally reaches more than 2Mhz, and ranging code is continuous print, the code phase resolution that just can reach sub-meter grade is followed the tracks of by code phase, and ranging code is not continuous print in the present invention, data block is stored between adjacent ranging code, the bandwidth of D (t) signal only has hundreds of KHz (narrow bandwidth), the sampling clock of usual employing 1Msps goes sampling, now the resolution of clock only has 1us, and such synchronous error is obviously too large.

In a second embodiment, multiple relevant peaks is comprehensively used to estimate the initial optimal estimation θ arriving the local moment of pulse corresponding to first relevant peaks by evaluation unit 41, and the frequency deviation k of transmitter A0 and receiver A1 (this sentences receiver A1 is example) clock, thus local clock moment of receiver A1 and frequency are adjusted, with synchronous with transmitter A0, achieve and achieve high-precision time synchronized when the lower sampling clock of frequency ratio and narrow band signal, with reference to Fig. 6, Fig. 6 gives use 48 pulses, pulse utilization rate rate is respectively 0.6, 0.8, optimal estimation θ mean square error when 1, usually 10 nanosecond orders can be reached through measuring synchronous precision, wherein, abscissa Eb/N0 in Fig. 6 is the energy of every Bit data of the radio signal received and the ratio of Carrier To Noise Power Density, it is the universal method representing the radio signal quality received in this area, the ordinate RMSE of Fig. 6 is the root-mean-square error between the estimated value of θ and actual value, and unit is nanosecond, is the universal method representing valuation quality in this area.

Further, execute at fm broadcast receiver of the present invention second on the basis of example, propose the 3rd embodiment of fm broadcast receiver, in the third embodiment, described time difference calculating unit 42 also for:

According to described remote location information and local position information, calculate signal from described frequency-modulated broadcast transmitter to the propagation time of fm broadcast receiver;

If the remote location information of transmitter A0 is P _tx=[x _tx, y _tx, z _tx], the local position information of receiver A1 is P _rx=[x _rx, y _rx, z _rx], time difference calculating unit 42 calculates the propagation time T of signal spontaneous emission machine A0 to receiver A1 _prop=| P _tx-P _rx|/C, wherein C is the light velocity.

According to described far-end temporal information, estimated time information and transmission time, calculate the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock.

Far-end temporal information is included in Preset Time (as T _selin) first the transmitter A0 time that pulse is corresponding be θ _tx, the local zone time that receiver receives first pulse corresponding is θ _rxthe time difference T of=θ, transmitter A0 and receiver A1 clock _e=θ _tx+ Tprop-θ _rx.

In the present embodiment, the signal propagation time is between the transmitter and receiver calculated according to the remote location information of the local position information of receiver and transmitter by time difference calculating unit 42, again according to the information and transmission time estimated time of the far-end temporal information of transmitter, receiver, calculate the time difference between receiver clock and transmitter clock, obtain the time difference between receiver clock and transmitter clock with a kind of simple account form.

Further, execute at fm broadcast receiver of the present invention 3rd on the basis of example, propose the 4th embodiment of fm broadcast receiver, in the fourth embodiment, described lock unit 43 also for:

According to the frequency nominal value of described relative frequency difference and described fm broadcast receiver, adjust the frequency of described fm broadcast receiver clock;

According to the frequency nominal value of described time difference and described fm broadcast receiver, adjust the moment of described fm broadcast receiver clock.

In the present embodiment, fm broadcast receiver safeguards local zone time with numeral counter second usually in digital circuit, and this digital circuit has a work clock, and its frequency exists fluctuation, but frequency nominal value (unit: MHz) is known, setting this frequency nominal value is Fdef.Receiver A1 gives tacit consent to when starting, if the timer digital second of receiver A1 often increases Fdef, it's one second has past the time, namely overflows once second.When transmitter A0 and receiver A1 life period difference T being detected _etime, then by second counter value reduce { T accordingly _e* Fdef} (needs round up, and also may be negative values).When frequency deviation k being detected, illustrate that a work clock actual frequency of this digital circuit is Fdef/ (1+k), therefore fm broadcast receiver A1 should adjust a second overflow mechanism, becomes and thinks that it's one second has past the time when numeral counter second reaches when frequency nominal value adds Fdef/ (1+K) (needs round up).

Through the above description of the embodiments, those skilled in the art can be well understood to the mode that above-described embodiment method can add required general hardware platform by software and realize, hardware can certainly be passed through, but in a lot of situation, the former is better execution mode.Based on such understanding, technical scheme of the present invention can embody with the form of software product the part that prior art contributes in essence in other words, this computer software product is stored in a storage medium (as ROM/RAM, magnetic disc, CD), comprising some instructions in order to make a station terminal equipment (can be mobile phone, computer, server, air conditioner, or the network equipment etc.) perform the method for each embodiment of the present invention.

These are only the preferred embodiments of the present invention; not thereby the scope of the claims of the present invention is limited; every utilize specification of the present invention and accompanying drawing content to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present invention.

Claims (10)

1. based on a clock synchronizing method for digital frequency modulation broadcast, it is characterized in that, the described clock synchronizing method based on digital frequency modulation broadcast comprises:

Fm broadcast receiver receives the Radio Data Broadcast Signal that the frequency-modulated broadcast transmitter synchronous with the standard time is broadcasted;

Described fm broadcast receiver demodulates time synchronizing signal in described Radio Data Broadcast Signal;

Described fm broadcast receiver obtains the local time information that it receives described time synchronizing signal;

Described fm broadcast receiver according to the local position information of self, described time synchronizing signal and local time information, synchronously moment of this fm broadcast receiver local clock and frequency.

2. as claimed in claim 1 based on the clock synchronizing method of digital frequency modulation broadcast, it is characterized in that, the far-end temporal information that described time synchronizing signal comprises ranging code, described frequency-modulated broadcast transmitter broadcasts described ranging code and the remote location information of described frequency-modulated broadcast transmitter

Described fm broadcast receiver is according to described time synchronizing signal, local time information and local position information, and synchronously the moment of this fm broadcast receiver local clock and the step of frequency comprise:

Fm broadcast receiver, according to described local time information, estimates that this fm broadcast receiver receives the evaluation time information of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter;

Fm broadcast receiver, according to described remote location information, local position information, far-end temporal information and evaluation time information, calculates the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock;

Fm broadcast receiver according to described time difference and relative frequency difference, synchronously moment of this fm broadcast receiver local clock and frequency.

3., as claimed in claim 2 based on the clock synchronizing method of digital frequency modulation broadcast, it is characterized in that, described fm broadcast receiver obtains its step receiving the local time information of described time synchronizing signal and comprises;

Described fm broadcast receiver generates the local ranging code identical with the pulse signal waveform of the ranging code that described frequency-modulated broadcast transmitter sends;

Described fm broadcast receiver obtains the local clock during impulse waveform phase alignment of the ranging code that the impulse waveform of described local ranging code and described frequency-modulated broadcast transmitter send;

Described fm broadcast receiver, according to described local time information, estimates that this fm broadcast receiver receives the evaluation time information of described ranging code and described fm broadcast receiver comprises with the step of the relative frequency difference between frequency-modulated broadcast transmitter:

Each pulse of the ranging code that described fm broadcast receiver sends according to described frequency-modulated broadcast transmitter and the nominal delay of an one pulse and described local clock, estimate that this fm broadcast receiver receives the estimation clock value of first pulse of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter.

4. as claimed in claim 2 based on the clock synchronizing method of digital frequency modulation broadcast, it is characterized in that, described fm broadcast receiver is according to described remote location information, local position information, far-end temporal information and evaluation time information, and the step calculating the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock comprises:

Described fm broadcast receiver, according to described remote location information and local position information, calculates signal from described frequency-modulated broadcast transmitter to the propagation time of fm broadcast receiver;

Described fm broadcast receiver according to described far-end temporal information, estimated time information and transmission time, calculate the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock.

5., as claimed in claim 2 based on the clock synchronizing method of digital frequency modulation broadcast, it is characterized in that, described fm broadcast receiver is according to described time difference and relative frequency difference, and the step in the moment and frequency that adjust self clock comprises:

Described fm broadcast receiver, according to the frequency nominal value of described relative frequency difference and described fm broadcast receiver, adjusts the frequency of described fm broadcast receiver clock;

Described fm broadcast receiver, according to the frequency nominal value of described time difference and described fm broadcast receiver, adjusts the moment of described fm broadcast receiver clock.

6. a fm broadcast receiver, is characterized in that, described fm broadcast receiver comprises:

Signal receiving module, for receiving the Radio Data Broadcast Signal that the frequency-modulated broadcast transmitter synchronous with the standard time is broadcasted;

Demodulation module, for demodulating time synchronizing signal in described Radio Data Broadcast Signal;

Local zone time acquisition module, receives the local time information of described time synchronizing signal for obtaining described fm broadcast receiver;

Synchronization module, for the local position information according to self, described time synchronizing signal and local time information, synchronously moment of this fm broadcast receiver local clock and frequency.

7. fm broadcast receiver as claimed in claim 6, is characterized in that, the far-end temporal information that described time synchronizing signal comprises ranging code, described frequency-modulated broadcast transmitter broadcasts described ranging code and the remote location information of described frequency-modulated broadcast transmitter,

Described synchronization module comprises:

Evaluation unit, for according to described local time information, estimates that this fm broadcast receiver receives the evaluation time information of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter;

Time difference calculating unit, for according to described remote location information, local position information, far-end temporal information and evaluation time information, calculates the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock;

Lock unit, for according to described time difference and relative frequency difference, synchronously moment of this fm broadcast receiver local clock and frequency.

8. fm broadcast receiver as claimed in claim 7, it is characterized in that, described local zone time acquisition module comprises;

Pulse generate unit, for generating the local ranging code identical with the pulse signal waveform of the ranging code that described frequency-modulated broadcast transmitter sends;

Clock value acquiring unit, the local clock during impulse waveform phase alignment of the ranging code that impulse waveform and described frequency-modulated broadcast transmitter for obtaining described local ranging code send;

Described evaluation unit, also for each pulse of ranging code of sending according to described frequency-modulated broadcast transmitter and the nominal delay of its first pulse and described local clock, estimate that this fm broadcast receiver receives the estimation clock value of first pulse of described ranging code and described fm broadcast receiver and the relative frequency difference between frequency-modulated broadcast transmitter.

9. fm broadcast receiver as claimed in claim 7, is characterized in that, described time difference calculating unit also for:

According to described remote location information and local position information, calculate signal from described frequency-modulated broadcast transmitter to the propagation time of fm broadcast receiver;

According to described far-end temporal information, estimated time information and transmission time, calculate the time difference between described fm broadcast receiver clock and frequency-modulated broadcast transmitter clock.

10. fm broadcast receiver as claimed in claim 7, is characterized in that, described lock unit also for:

According to the frequency nominal value of described relative frequency difference and described fm broadcast receiver, adjust the frequency of described fm broadcast receiver clock;

According to the frequency nominal value of described time difference and described fm broadcast receiver, adjust the moment of described fm broadcast receiver clock.