CN114895331A - Time signal measuring device and method based on satellite navigation signals - Google Patents
Time signal measuring device and method based on satellite navigation signals Download PDFInfo
- Publication number
- CN114895331A CN114895331A CN202210521890.5A CN202210521890A CN114895331A CN 114895331 A CN114895331 A CN 114895331A CN 202210521890 A CN202210521890 A CN 202210521890A CN 114895331 A CN114895331 A CN 114895331A
- Authority
- CN
- China
- Prior art keywords
- signal
- module
- frequency
- time
- difference
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/13—Receivers
- G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
- G01S19/25—Acquisition or tracking or demodulation of signals transmitted by the system involving aiding data received from a cooperating element, e.g. assisted GPS
- G01S19/256—Acquisition or tracking or demodulation of signals transmitted by the system involving aiding data received from a cooperating element, e.g. assisted GPS relating to timing, e.g. time of week, code phase, timing offset
-
- G—PHYSICS
- G04—HOROLOGY
- G04F—TIME-INTERVAL MEASURING
- G04F10/00—Apparatus for measuring unknown time intervals by electric means
- G04F10/04—Apparatus for measuring unknown time intervals by electric means by counting pulses or half-cycles of an ac
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The invention discloses a time signal measuring device and method based on satellite navigation signals, the device comprises a local reference source, a signal receiving and source difference measuring module, a controllable frequency division module, a parameter generating module, a delay gate control module, a time difference measuring module and a time difference correction calculating module, the source difference value of the local reference signal is obtained through the measurement of the received satellite navigation signals, a pulse to be measured of the measured time signal is used as a door opening signal, an adjacent FTF pulse signal generated by the controllable frequency division module is used as a door closing signal, the apparent time difference between the two is measured, the actual time difference corresponding to the apparent time difference is calculated, and therefore the time deviation of the measured time signal is further obtained. The invention improves the metering accuracy of the local reference source and the accuracy of the measurement time signal by introducing the satellite navigation signal, and has the advantages of high measurement accuracy, low cost, wide application range and the like.
Description
Technical Field
The invention belongs to the technical field of time-frequency testing, and particularly relates to a time signal measuring device and method based on satellite navigation signals.
Background
In the prior art, when a time-frequency signal is measured by using a satellite navigation signal, an independent satellite time service module is usually used to receive the satellite navigation signal, measure the deviation of a local reference frequency, record the adjustment information of a local reference source, and tame the local reference source.
Here, due to the fact thatThe satellite time service module is different from the local reference source, namely different reference sources are adopted, mainly because the satellite time service module uses an independent reference source carried by the satellite time service module. The measurement portion for performing frequency difference measurement on the frequency difference between the local reference signal and the satellite navigation signal is heterogeneous with the adjustment portion for adjusting the local reference frequency. When time-frequency signal measurement is carried out based on the principle, the accuracy is not high and can only reach 10 -8 To 10 -9 Of the order of (d), there is a phase deviation from the measured time-second pulse.
Disclosure of Invention
The invention mainly solves the technical problem of providing a time signal measuring device and method based on satellite navigation signals, and solves the problems of different time-frequency measurement sources and low measurement precision in the prior art.
In order to solve the technical problems, the invention adopts a technical scheme that: the time signal measuring device comprises a local reference source, a signal receiving and source difference measuring module, a controllable frequency division module, a parameter generating module, a delay gate control module, a time difference measuring module and a time difference correction calculating module, wherein the local reference source outputs a local reference signal to the signal receiving and source difference measuring module;
the local reference signal is also input into the controllable frequency division module to generate a main clock, the parameter generation module generates an output frequency adjustment value, the main clock is subjected to frequency division to generate an FTF pulse signal, and the FTF pulse signal is input into the delay gating module;
the time-delayed gating module also acquires a close pulse in the FTF pulse signals adjacent to the time-delayed gating module as a door-closing signal after the second pulse to be detected appears, and inputs the door-closing signal to the time difference measuring module;
the time difference measuring module is connected to a local reference signal of the local reference source and is used as a reference clock to measure the apparent time difference between the door opening signal and the door closing signal;
and the time difference correction calculation module receives the apparent time difference and the source difference value of the local reference signal, and calculates the actual time difference corresponding to the apparent time difference, thereby further obtaining the time deviation of the measured time signal.
Preferably, the signal receiving and source difference measuring module includes a frequency conversion sub-module, a demodulation sub-module and a source difference calculating module, and the frequency conversion sub-module is based on the actual frequency value f of the local reference signal 0 ', actual frequency value f of frequency multiplied local carrier signal c '＝Mf 0 ', wherein M denotes a frequency multiplier, for an incoming satellite navigation signal f sz Performing down-conversion processing to obtain a low intermediate frequency signal, inputting the low intermediate frequency signal into a demodulation submodule, and outputting a carrier frequency difference delta f by the frequency conversion submodule c ', the demodulation sub-module performs carrier loop tracking demodulation by using the local carrier signal to obtain demodulation information, and the demodulation sub-module further outputs a tracking frequency difference Δ f c ", said carrier frequency difference and tracking frequency difference are added by Δ f c '+Δf c ″＝f c '-f sz And then the source difference value of the local reference signal is calculated by a source difference calculating module
Wherein f is 0 Nominal frequency, f, representing a local reference source 0 '＝f c '/M＝(Δf c '+Δf c ″+f sz )/M。
Preferably, the controllable frequency dividing module includes a first adder and a delay register, the frequency adjustment value from the parameter generating module is input to the first adder, and is periodically accumulated with an accumulated value stored in the delay register, and after the accumulated value is accumulated to a second period, the first adder updates the input frequency adjustment value and continues accumulating, the first adder is further cascaded with an edge detector for detecting edge transition of an output waveform, and the edge detector outputs the pulse per second signal.
Preferably, the parameter generation module obtains a source difference value of the local reference signal
Actual frequency of local reference signal
After K times in the controllable frequency division module, the actual frequency of the generated main clock is Kf 0 ', when a period T is generated x The parameter generation module correspondingly calculates the frequency adjustment value to be 2 N /Kf 0 'T x And N represents the word length of the phase accumulator of the DDS.
Preferably, the time difference measuring module measures the apparent time difference τ between the door opening signal and the door closing signal p The time difference correction calculation module receives the source difference value of the local reference signal from the signal receiving and source difference measurement module
Further calculating the actual time difference between the door opening signal and the door closing signal
And according to the number of FTF pulses between the door opening signal and adjacent local second pulses and the actual time difference tau c And obtaining the time deviation of the measured time signal.
Preferably, the time difference measuring device further comprises a peak detecting and shaping module, which is used for performing peak detection and shaping on the input measured time signal and then inputting the input measured time signal to the delay gating module and the time difference measuring module respectively.
Based on the same conception, the invention also provides a time signal measuring method based on the satellite navigation signal, which comprises the following steps:
receiving a satellite navigation signal, and performing source difference measurement on the local reference signal by using the satellite navigation signal to obtain a source difference value of the local reference signal;
adjusting the frequency by using the source difference value of the local reference signal, and generating an FTF pulse signal and a local second time signal by controllable frequency division;
collecting a pulse to be measured of a measured time signal as a door opening signal, and collecting a pulse in the FTF pulse signal adjacent to the pulse to be measured as a door closing signal after the pulse to be measured appears;
measuring the apparent time difference between the door opening signal and the door closing signal by taking the local reference signal as a reference clock;
and calculating the actual time difference corresponding to the apparent time difference by using the source difference value of the local reference signal, thereby further obtaining the time deviation of the measured time signal.
Preferably, the method for performing source difference measurement on the local reference signal by using the satellite navigation signal includes:
frequency multiplication is carried out on the local reference signal to obtain a local carrier signal,
demodulating and receiving the satellite navigation signal by using the local carrier signal to obtain the actual frequency difference between the local carrier signal and the satellite navigation signal in real time,
calculating to obtain the actual frequency of the local carrier signal by using the actual frequency of the satellite navigation signal and the actual frequency difference, further obtaining the actual frequency of the local reference signal,
and calculating to obtain a source difference value of the local reference signal by using the actual frequency and the nominal frequency of the local reference signal.
Preferably, the apparent time difference τ between the door opening signal and the door closing signal is measured p Source difference value of the local reference signal
Further calculating the actual time difference between the door opening signal and the door closing signal
And according to the number of FTF pulses between the door opening signal and adjacent local second pulses and the actual time difference tau c And obtaining the time deviation of the measured time signal.
Preferably, the measured time signal is collected as a door opening signal after peak detection and shaping.
The invention has the beneficial effects that: the invention discloses a time signal measuring device and a method based on satellite navigation signals, the device comprises a local reference source, a signal receiving and source difference measuring module, a controllable frequency dividing module, a parameter generating module, a delay gate control module, a time difference measuring module and a time difference correction calculating module, wherein the source difference value of the local reference signal is obtained by receiving the satellite navigation signal measurement, a pulse to be measured of a measured time signal is taken as a door opening signal, an adjacent FTF pulse signal generated by the controllable frequency dividing module is taken as a door closing signal, the apparent time difference between the two signals is measured, and the actual time difference corresponding to the apparent time difference is calculated, so that the time deviation of the measured time signal is further obtained. The invention improves the metering accuracy of the local reference source and the accuracy of the measurement time signal by introducing the satellite navigation signal, and has the advantages of high measurement accuracy, low cost, wide application range and the like.
Drawings
FIG. 1 is a schematic diagram of an embodiment of a time signal measurement device based on satellite navigation signals according to the present invention;
FIG. 2 is a schematic diagram of a signal receiving and measuring module in another embodiment of the apparatus for measuring time signal based on satellite navigation signal according to the present invention;
FIG. 3 is a schematic diagram of a controllable frequency-division module in another embodiment of the apparatus for measuring a time signal based on a satellite navigation signal according to the present invention;
FIG. 4 is a waveform diagram illustrating the generation of a controllable frequency-division module in another embodiment of the apparatus for measuring a time signal based on a satellite navigation signal according to the present invention;
FIG. 5 is a timing diagram illustrating second time calibration in another embodiment of the apparatus for measuring a time signal based on a satellite navigation signal according to the present invention;
FIG. 6 is a timing diagram illustrating time difference measurement in another embodiment of the apparatus for measuring a time signal based on a satellite navigation signal according to the present invention;
FIG. 7 is a flowchart of an embodiment of a method for measuring a time signal based on a satellite navigation signal according to the present invention.
Detailed Description
In order to facilitate an understanding of the invention, the invention is described in more detail below with reference to the accompanying drawings and specific examples. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It is to be noted that, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
The embodiments will be described in detail below with reference to the accompanying drawings.
FIG. 1 is a block diagram of an embodiment of a time signal measurement device based on satellite navigation signals. As can be seen from fig. 1, the system comprises a local reference source 11, a signal receiving and source difference measuring module 12, a controllable frequency dividing module 14, a parameter generating module 13, a delay gating module 16, a time difference measuring module 17 and a time difference correction calculating module 18, wherein the local reference source 11 outputs a local reference signal and inputs the local reference signal to the signal receiving and source difference measuring module 12, the signal receiving and source difference measuring module 12 receives a satellite navigation signal, performs source difference measurement on the local reference signal to obtain a source difference value of the local reference signal, and outputs the source difference value to the parameter generating module 13 and the time difference correction calculating module 18;
the local reference signal is further input to the controllable frequency division module 14 as a main clock, the parameter generation module 13 generates an output frequency adjustment value, divides the frequency of the main clock to generate an FTF (Fundamental time frame) pulse signal, and inputs the FTF pulse signal to the delay gating module 16;
preferably, in practical applications, the signal receiving and source difference measuring module 12 and the controllable frequency dividing module 14 may respectively include frequency multipliers, frequency multiplication of the local reference signal input by the local reference source 11 may be respectively implemented inside the signal receiving and source difference measuring module 12 and the controllable frequency dividing module 14, the frequency multiplication values may be different, and frequency synthesis may be performed based on the local reference signal to generate multiple required frequency components. However, these frequency components are all referenced to the local reference signal, and therefore have the same characteristics and the same accuracy of the same frequency.
The measured time signals are respectively input into the delay gate control module 16 and the time difference measuring module 17, a to-be-measured second pulse of the measured time signals is used as a door opening signal to be collected, after the to-be-measured second pulse appears, the delay gate control module 16 collects a close pulse in the adjacent FTF pulse signals as a door closing signal, and inputs the door closing signal into the time difference measuring module 17;
the time difference measuring module 17 is connected to a local reference signal of the local reference source, and accordingly serves as a reference clock to measure the apparent time difference between the door opening signal and the door closing signal;
the time difference correction calculation module 18 receives the apparent time difference and the source difference of the local reference signal, and calculates an actual time difference corresponding to the apparent time difference, thereby further obtaining a measured time difference between the measured time signal and the reference time.
Preferably, for the signal receiving and source difference measuring module 12, it receives the satellite navigation signal through the satellite antenna, performs down-conversion and demodulation on the satellite navigation signal, and obtains the satellite navigation signal therefrom, and the receiving process uses the local reference signal output by the local reference source to perform down-conversion and in-demodulation carrier loop tracking. Therefore, the signal receiving and source difference measuring module 12 receives signals by using a local reference signal output by the local reference source 11 as a source signal, and the local reference source 11 also provides signal sources for the controllable frequency division module 14 and the time difference measuring module 17 in the device, thereby ensuring that the local reference source 11 in the device is a uniform reference source and ensuring the homology of each module generating pulse per second.
With the popularization and use of the satellite navigation positioning modules and chips such as the GPS, the Beidou and the like, the satellite navigation positioning module has lower market price, and the cost of the signal receiving and source difference measuring module 12 can be obviously reduced. Meanwhile, the precision requirement on a local reference source for generating a local reference signal is not high, and only a constant-temperature crystal oscillator and a temperature compensation crystal oscillator are needed, and an atomic clock with higher price is not needed, so that the price can be reduced.
For the purposes of the present invention, the local reference source 11 includes a quartz crystal, a constant temperature crystal oscillator, a temperature compensated crystal oscillator, and other low-cost common reference sources, which may have aging and drift problems, that is, a problem of frequency change over time, or a problem of frequency stability, for example, the frequency stability of the quartz crystal may reach 10 -9 Day, even 10 -11 Day, for a 10MHz quartz crystal, the frequency will typically not vary by more than 0.1Hz within a day. The frequency stability of the quartz crystal is lower than that of the oven controlled crystal oscillator, which is indicated in that the frequency of the quartz crystal changes more or faster than that of the oven controlled crystal oscillator along with the time, so that for the problem of dynamic frequency change of the reference source, the actual frequency value needs to be accurately measured, and the dynamic and real-time performance of the measurement can be maintained.
The invention obtains accurate carrier frequency of satellite navigation signals by utilizing carrier demodulation and telegraph text ephemeris of received satellite navigation signals, and the accuracy of the carrier frequency is 10 -13 To 10 -14 Of the local reference signal, the source difference of the local reference signal being obtainable using the high-precision level of the measurement signal
Can reach 10 -11 To 10 -12 Of the order of magnitude of (d). Although the local reference source has lower frequency stabilityHowever, the method of the present invention can perform high-precision measurement on the actual frequency, so as to obtain an actual frequency measurement value with very high precision, and the measurement has real-time performance.
Preferably, referring to fig. 2, the signal receiving and source difference measuring module includes a frequency conversion sub-module 121 and a demodulation sub-module 122, the frequency conversion sub-module 121 performs frequency down-conversion processing on an input satellite navigation signal by using a local carrier signal that is frequency-multiplied based on the local reference signal, so as to obtain a low-intermediate frequency baseband signal, the low-intermediate frequency baseband signal is input to the demodulation sub-module 122, the frequency conversion sub-module 121 further outputs a carrier frequency difference, the demodulation sub-module 122 performs carrier loop tracking demodulation by using the local carrier signal, so as to obtain demodulation information, the demodulation sub-module 122 further outputs a tracking frequency difference, and the carrier frequency difference and the tracking frequency difference are added by an adder 123 and then calculated by a source difference calculating module 124, so as to obtain the source difference.
Preferably, the carrier is generally in the L band for satellite navigation signals, and the frequency conversion sub-module 121 receives the local reference signal f from the local reference source 11 0 ' (actual frequency value) and then frequency multiplication is carried out in the carrier signal to obtain a local carrier signal f c ' (actual frequency value), then there is f c '＝Mf 0 ', where M denotes the frequency multiplier, then with the carrier f of the satellite navigation signal sz Mixing is performed (note that here the carrier f of the satellite navigation signal sz Is an actual value, since the satellite navigation signal has very high accuracy, the frequency value is a high-accuracy frequency value, and can be accurately obtained through ephemeris and link calculation in the demodulation information, and also represents a true value of the carrier frequency of the satellite navigation signal). The obtained low-intermediate frequency baseband signal is output to the demodulation sub-module 122, and the frequency conversion sub-module 121 outputs a carrier f relative to the satellite navigation signal sz Carrier frequency difference Δ f of c ' equivalent to coarse frequency difference, the demodulation sub-module 122 performs demodulation loop tracking processing on the input low intermediate frequency baseband signal, and further obtains the tracking frequency difference Δ f between the local carrier signal and the satellite navigation signal carrier in real time c ", which corresponds to the fine frequency difference,then, the carrier frequency difference and the tracking frequency difference are added by Δ f through the adder 123 c '+Δf c Corresponding to the addition of the coarse frequency difference and the fine frequency difference, the actual frequency difference Δ f of the local carrier signal relative to the carrier frequency of the satellite navigation signal can be obtained c ＝f c '-f sz ＝Δf c '+Δf c ". Δ f herein c ' and Δ f c "can be either a positive or a negative value, depending on the actual deviation.
Further, for a local reference source, the frequency of the local reference signal that it actually outputs should be f 0 '＝f c '/M＝(Δf c '+Δf c ″+f sz ) If the source difference value of the local reference signal is/M, the source difference value of the local reference signal is
Wherein f is 0 Representing the nominal frequency of the local reference source. In FIG. 2, the source difference of the local reference signal
The source difference calculating module 124 calculates and outputs the actual frequency difference output by the adder 123.
Further, the source difference value
The updating output is performed at second intervals, so that the error adjustment can be performed at second intervals even when the second clock output of the controllable frequency division module 14 is output, and the high-precision second clock output can be obtained without long-time observation.
Further, the parameter generation module 13 in fig. 1 generates a source difference value according to the source difference value
The frequency adjustment value required for the controllable frequency division module 14 to output the pulse per second is generated. How to base the source difference on the composition of the controllable frequency-dividing module 14 is further explained below in conjunction with the composition of the controllable frequency-dividing module
The control outputs the second pulse.
Referring to fig. 1, for the controllable frequency division module 14, the local reference signal input thereto is multiplied by the internal frequency multiplier and then used as the main clock, and the second pulse output can be obtained by controlling the frequency division of the main clock, but since the accuracy and stability of the local reference signal need to be corrected according to the satellite navigation signal, the error needs to be corrected according to the obtained source difference
The second pulse with high precision can be ensured to be output only by dynamically correcting the local reference signal.
Preferably, the controllable frequency divider module 14 uses a Direct Digital Synthesizer (DDS) as a core device, the DDS divides an input main clock to obtain a pulse per second, or the DDS accumulates at fixed phase intervals to obtain a period per second, and the phase intervals need to be adjusted according to an actual frequency of the local reference signal. For example, according to the foregoing, the nominal frequency of the local reference signal is f 0 Measured source difference value
The actual frequency of the local reference signal
After passing through the frequency multiplier, the frequency multiplication value is K, and the actual frequency of the main clock is Kf 0 ', when the actual frequency Kf of the master clock is used 0 When frequency division is carried out, N represents the word length or the digit number of a phase accumulator of the DDS, and the minimum phase interval is 2 pi/2 N For example, when a divide-by-two of the master clock is to be implemented, the frequency adjustment value is 2 N-1 The corresponding phase accumulation step is pi, and when the frequency division is performed on the master clock, the corresponding frequency adjustment value is 2 N-2 The corresponding phase accumulation step is pi/2, and so on.
Therefore, when obtaining the accurate actual frequency Kf of the master clock 0 ' after, to produceOne period being T x The corresponding frequency adjustment value can be calculated to be 2 N /Kf 0 'T x The corresponding phase accumulation step is 2 pi/Kf 0 'T x 。
Therefore, with the master clock as the clock source, when one step is accumulated per master clock cycle
Then pass through
One second pulse can be output from each master clock. But due to the actual frequency f of the local reference signal 0 ' if there is a deviation, it is necessary to measure the deviation continuously, i.e. to output a source difference every second
By continuously updating the source difference value every second
To dynamically adjust the accumulated step interval
The parameter generation module 13 in FIG. 1 is to generate the parameters
Converted to the DDS frequency adjustment value in the controllable frequency divider module 14 and maintained at a high numerical precision, for example, represented by a binary number from 16 bits to 32 bits, wherein
The middle N value represents different binary digits.
In practical application, there will be
In the case of a small value, i.e. 2 N Has a limited value of
The value is large, in this case, the output second pulse is not directly generated, but a periodic pulse with a short output period is generated, namely, the period generated is T x The corresponding frequency adjustment value can be calculated to be 2 N /Kf 0 'T x For example, FTF (Fundamental time frame) pulses of 10ms period, and then every 100 FTF pulses with a sequence number is selected as a pulse per second to be output.
Fig. 3 and 4 further show the internal components of the controllable frequency-dividing module 14 and the internal waveform generation schematic. Preferably, the controllable frequency dividing module includes a first adder 141 and a delay register 142, the frequency adjustment value from the parameter generating module is input to the first adder 141, and is periodically accumulated with the accumulated value stored in the delay register 142, and after the accumulation reaches a second period, the delay register 142 naturally overflows, then the first adder 141 updates the input frequency adjustment value and continues accumulation, the first adder 141 is further cascaded with an edge detector 144 for detecting edge transition of the output waveform, and the edge detector 144 outputs the second pulse signal.
Further preferably, the controllable frequency division module further includes a second adder 143 cascaded between the first adder 141 and the edge detector 144, and the second adder 143 receives the phase adjustment value output by the signal receiving and source difference measuring module, and outputs the pulse-per-second signal after performing edge detection by the edge detector after adding the phase adjustment value to the result output by the first adder 141.
Preferably, the frequency adjustment value from the parameter generation module is input to the first adder 141, and is continuously added to the value accumulated in the delay register 142 under the driving of the master clock. Normally, exactly one second pulse is output after accumulating for one second period, and then the accumulated value in the delay register 142 continues to perform periodic accumulation on the input frequency adjustment value. At each oneSource difference value sigma in signal receiving and source difference measuring module in second period s The correction is continuously obtained, and accordingly, the frequency adjustment value can be subjected to error correction, so that the output pulse per second is more accurate. Therefore, the contradiction that the measuring time length and the measuring precision can not be reconciled in the prior art is overcome.
In fig. 4, a schematic diagram T141 of a waveform of the signal of the accumulated value output after passing through the first adder 141 is shown, and it can be seen that the waveform T141 is a triangular wave with an accumulated period, that is, a period of one second, and if the waveform T141 is directly subjected to edge detection by the following edge detector 144, a pulse-per-second signal can be output.
Further preferably, a second adder 143 is further provided after the first adder 141 in fig. 3, and the second adder 143 adds the accumulated value output by the first adder 141 to the phase adjustment value output by the signal receiving and source difference measuring module, so as to further correct the phase error of the pulse per second output. The phase adjustment value is obtained by detecting a phase jitter occurring when the source difference measurement is performed on the local reference signal and the satellite carrier signal, and correspondingly, a waveform T143 output after passing through the second adder 143 is shown in fig. 4, and it can be seen that the waveform T143 performs phase adjustment based on the waveform T141, and the phase of the waveform T143 is slightly advanced with respect to the phase of the waveform T141. Further shown in fig. 4 is an edge-detected waveform T144 for waveform T143 after passing through edge detector 144. By adding the phase adjustment value, the phase of the output pulse per second can be further subjected to error correction, so that the problem of phase jitter occurring in a local reference signal can be eliminated, and the accuracy of the output pulse per second can be improved.
Preferably, when the controllable frequency division module is implemented specifically, the frequency adjustment value is used as a step size, the master clock is used for accumulating, the FTF pulse with a period of 10ms is generated by natural overflow, and then the FTF pulse is counted in a modulo 100 manner, that is, the FTF pulse is output cyclically with the number of 0-99, wherein the FTF pulse with the number of 0 is designated as the pulse corresponding to the second time. Thus, there are 100 FTF pulses between two consecutive second instants.
Preferably, the standard satellite time, that is, the TOD information and the satellite time in the navigation message, can be obtained by demodulating the ephemeris information in the satellite navigation signal, and then the difference between the local time and the satellite time, that is, the clock difference, is obtained when the local time beat signal generated by local recovery is used to receive the satellite recovered by the source difference measurement module. And inputting a phase adjustment value of the controllable frequency division module by taking the clock difference value as a basis until the clock difference value is close to 0, and considering that the phase synchronization of the local time and the satellite time is established.
Therefore, with reference to fig. 1 and 5, after the controllable frequency division module generates the FTF pulse according to the frequency adjustment value, the FTF pulse is fed back to the signal receiving and source difference measurement module, and the difference value between the local time and the satellite time, i.e. the clock difference value, is input to the controllable frequency division module as a phase adjustment value to regulate and control the output phase of the FTF pulse corresponding to the counted local second time, which is mainly generated based on that the FTF pulse is pushed by the master clock to generate the DDS, where the output time is the local master clock time, and when the DDS pulse lags behind the satellite, the real time (the minimum precision is 1 master clock cycle), the delay can be corrected by the mantissa of the DDS transition edge, that is, the mantissa of the DDS transition edge is subjected to phase regulation by modifying the value of the step length accumulated therein. The correction process of the local time with respect to the satellite time can be seen schematically by the display of fig. 5.
Therefore, the accuracy of the output pulse per second frequency (or period) is determined for the frequency adjustment value output by the parameter generation module; the time accuracy of outputting the pulse per second is determined by the phase adjustment value output by the signal receiving and source difference measuring module.
With reference to fig. 1 and 6, the time difference measuring module 17 collects a pulse to be measured P1 of the measured time signal as a door opening signal, and the pulse to be measured P1 is also collected by the delay gate control module 16, and then the delay gate control module 16 collects a close pulse P2 of the input FTF pulse signal as a door closing signal, that is, the close pulse P2 is an FTF pulse immediately following the pulse to be measured P1, and the FTF pulse shown in fig. 6 is the FTF pulse with the serial number 5.
Thus, the time difference measuring module 17 can acquire and obtain the door closing signal and the door opening signal in sequence, the time difference exists between the two signals, the time difference is measured by taking the local reference signal provided by the local reference source as the reference clock, namely measuring the time difference after the local reference signal or the local reference signal is subjected to frequency multiplication, and the time difference is called as the apparent time difference tau p Thus, the apparent time difference τ p The accuracy of the local reference signal is determined by the accuracy of the local reference signal, which is accurately obtained by the signal receiving and source difference measuring module.
Thus, further, the apparent time difference τ is obtained in the time difference measuring module 17 p Then, the time difference is input to a time difference correction calculation module 18, and the time difference correction calculation module 18 also receives the source difference value of the local reference signal from the signal receiving and source difference measurement module
Further calculating the actual time difference between the pulse per second P1 to be measured and the close pulse P2
Further, as shown in fig. 6, it can be seen that the second time corresponding to the second pulse P1 to be measured is a pulse sequence having a period of 10ms for the FTF pulse, and the FTF pulse No. 0 corresponds to the second pulse time. Therefore, the time difference measuring module 17 can further calculate the time deviation of the to-be-measured second pulse P1 with respect to the satellite time, because the time difference measuring module 17 receives the FTF pulse and the local second pulse (PPS) from the controllable frequency dividing module, that is, the local second pulse calibrated with the satellite time, and based on fig. 6, it can be seen that according to the door-open signal, that is, the number of FTF pulses between the to-be-measured second pulse P1 and the adjacent local second pulse, and the actual time difference τ c And obtaining the accurate time deviation of the measured time signal.
As shown in FIG. 6, there are 4 FTF pulse intervals between the PPS P1 under test and the adjacent local PPS P3 before, according to the foregoingCalculated actual time difference
The time deviation between the measured second pulse P1 with respect to the adjacent local second pulse P3 is 50- τ c (ms). Therefore, the time difference correction calculation module 18 can obtain the accurate time deviation of the measured time signal.
Further, fig. 1 also includes a peak detection and shaping module 19, which is mainly used for detecting and shaping the input measured time signal, so as to avoid the peak value of the input measured time signal being too small or too large, and avoid the input of distorted signals or interference signals after shaping the measured time signal, thereby ensuring the purity of the measured time signal.
Based on the same concept, the invention also provides a time signal measuring method based on the satellite navigation signal, which is combined with the figure 7 and comprises the following steps:
step S1: receiving a satellite navigation signal, and performing source difference measurement on the local reference signal by using the satellite navigation signal to obtain a source difference value of the local reference signal;
step S2: adjusting the frequency by using the source difference value of the local reference signal, and generating an FTF pulse signal and a local second time signal by controllable frequency division;
step S3: collecting a pulse to be measured of a measured time signal as a door opening signal, and collecting a pulse in the FTF pulse signal adjacent to the pulse to be measured as a door closing signal after the pulse to be measured appears;
step S4: measuring the apparent time difference between the door opening signal and the door closing signal by taking the local reference signal as a reference clock;
step S5: and calculating the actual time difference corresponding to the apparent time difference by using the source difference value of the local reference signal, thereby further obtaining the time deviation between the measured time signal and the local second moment.
Preferably, the method for performing source difference measurement on the local reference signal by using the satellite navigation signal includes:
frequency multiplication is carried out on the local reference signal to obtain a local carrier signal,
demodulating and receiving the satellite navigation signal by using the local carrier signal to obtain the actual frequency difference between the local carrier signal and the satellite navigation signal in real time,
calculating to obtain the actual frequency of the local carrier signal by using the actual frequency of the satellite navigation signal and the actual frequency difference, further obtaining the actual frequency of the local reference signal,
and calculating to obtain a source difference value of the local reference signal by using the actual frequency and the nominal frequency of the local reference signal.
Preferably, the apparent time difference τ between the door opening signal and the door closing signal is measured p Source difference value of the local reference signal
Further calculating the actual time difference between the door opening signal and the door closing signal
And according to the number of FTF pulses between the door opening signal and adjacent local second pulses and the actual time difference tau c And obtaining the accurate time deviation of the measured time signal.
Preferably, the measured time signal is collected as a door opening signal after peak detection and shaping are performed. For specific content, reference may be made to the foregoing description of an embodiment of a time signal measurement device based on a satellite navigation signal, which is not described herein again.
Based on the description of the above embodiments, the present invention discloses a time signal measurement device and method based on satellite navigation signals, the device includes a local reference source, a signal receiving and source difference measurement module, a controllable frequency division module, a parameter generation module, a delay gate control module, a time difference measurement module, and a time difference correction calculation module, a source difference value of the local reference signal is obtained by receiving satellite navigation signal measurement, a second pulse to be measured of a measured time signal is used as a gate-open signal, an adjacent FTF pulse signal generated by the controllable frequency division module is used as a gate-close signal, an apparent time difference between the two signals is measured, and an actual time difference corresponding to the apparent time difference is calculated, thereby further obtaining a time deviation of the measured time signal. The invention improves the metering accuracy of the local reference source and the accuracy of the measurement time signal by introducing the satellite navigation signal, and has the advantages of high measurement accuracy, low cost, wide application range and the like.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent structural changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. A time signal measuring device based on satellite navigation signals is characterized by comprising a local reference source, a signal receiving and source difference measuring module, a controllable frequency dividing module, a parameter generating module, a delay gate control module, a time difference measuring module and a time difference correction calculating module, wherein the local reference source outputs a local reference signal to the signal receiving and source difference measuring module;
the local reference signal is also input into the controllable frequency division module to generate a main clock, the parameter generation module generates an output frequency adjustment value, the main clock is subjected to frequency division to generate an FTF pulse signal, and the FTF pulse signal is input into the delay gating module;
the time-delayed gating module also acquires a close pulse in the FTF pulse signals adjacent to the time-delayed gating module as a door-closing signal after the second pulse to be detected appears, and inputs the door-closing signal to the time difference measuring module;
the time difference measuring module is connected to a local reference signal of the local reference source and is used as a reference clock to measure the apparent time difference between the door opening signal and the door closing signal;
and the time difference correction calculation module receives the apparent time difference and the source difference value of the local reference signal, and calculates the actual time difference corresponding to the apparent time difference, thereby further obtaining the time deviation of the measured time signal.
2. The satellite navigation signal-based time signal measurement device of claim 1, wherein the signal reception and source difference measurement module includes a frequency conversion sub-module, a demodulation sub-module, and a source difference calculation module, the frequency conversion sub-module based on an actual frequency value f of the local reference signal 0 ', actual frequency value f of frequency multiplied local carrier signal c '＝Mf 0 ', wherein M denotes a frequency multiplier, for an incoming satellite navigation signal f sz Performing down-conversion processing to obtain a low intermediate frequency signal, inputting the low intermediate frequency signal into a demodulation submodule, and outputting a carrier frequency difference delta f by the frequency conversion submodule c ', the demodulation sub-module performs carrier loop tracking demodulation by using the local carrier signal to obtain demodulation information, and the demodulation sub-module further outputs a tracking frequency difference Δ f c ", the carrier frequency difference and the tracking frequency difference are added by Δ f c '+Δf c ”＝f c '-f sz And then the source difference value of the local reference signal is calculated by a source difference calculating module
Wherein f is 0 Nominal frequency, f, of a local reference source 0 '＝f c '/M＝(Δf c '+Δf c ”+f sz )/M。
3. The satellite navigation signal-based time signal measuring apparatus according to claim 2, wherein the controllable frequency division module includes a first adder and a delay register, the frequency adjustment value from the parameter generation module is input to the first adder, and is periodically accumulated with an accumulated value stored in the delay register, and after the accumulation reaches one second period, the first adder updates the input frequency adjustment value and continues accumulation, the first adder is further cascaded with an edge detector for detecting edge transition of an output waveform, and the edge detector outputs the second pulse signal.
4. The apparatus according to claim 3, wherein the parameter generation module obtains a source difference value of the local reference signal
Actual frequency value of local reference signal
After K times in the controllable frequency division module, the actual frequency of the generated main clock is Kf 0 ', when a period T is generated x The parameter generation module correspondingly calculates to obtain a frequency adjustment value of 2 N /Kf 0 'T x And N represents the word length of the phase accumulator of the DDS.
5. The apparatus as claimed in claim 4, wherein the time difference measuring module measures the apparent time difference τ between the door opening signal and the door closing signal p The time difference correction calculation module receives the source difference value of the local reference signal from the signal receiving and source difference measurement module
Further calculating the actual time difference between the door opening signal and the door closing signal
And FTF pulse between adjacent local second pulses according to the door opening signalThe number of the impulses and the actual time difference tau c And obtaining the time deviation of the measured time signal.
6. The apparatus according to claim 5, further comprising a peak detection and shaping module, wherein the input measured time signal is subjected to peak detection and shaping, and then input to the delay gate module and the time difference measurement module, respectively.
7. A method for time signal measurement based on satellite navigation signals, comprising the steps of:
receiving a satellite navigation signal, and performing source difference measurement on the local reference signal by using the satellite navigation signal to obtain a source difference value of the local reference signal;
adjusting the frequency by using the source difference value of the local reference signal, and generating an FTF pulse signal and a local second time signal by controllable frequency division;
collecting a pulse to be measured of a measured time signal as a door opening signal, and collecting a pulse in the FTF pulse signal adjacent to the pulse to be measured as a door closing signal after the pulse to be measured appears;
measuring the apparent time difference between the door opening signal and the door closing signal by taking the local reference signal as a reference clock;
and calculating the actual time difference corresponding to the apparent time difference by using the source difference value of the local reference signal, thereby further obtaining the time deviation of the measured time signal.
8. The method of claim 7, wherein the method of performing source difference measurement on the local reference signal using the satellite navigation signal comprises:
frequency multiplication is carried out on the local reference signal to obtain a local carrier signal,
demodulating and receiving the satellite navigation signal by using the local carrier signal to obtain the actual frequency difference between the local carrier signal and the satellite navigation signal in real time,
calculating to obtain the actual frequency of the local carrier signal by using the actual frequency of the satellite navigation signal and the actual frequency difference, further obtaining the actual frequency of the local reference signal,
and calculating to obtain a source difference value of the local reference signal by using the actual frequency and the nominal frequency of the local reference signal.
9. The method of claim 8, wherein the apparent time difference τ between the door opening signal and the door closing signal is measured p Source difference value of the local reference signal
Further calculating the actual time difference between the door opening signal and the door closing signal
And according to the number of FTF pulses between the door opening signal and adjacent local second pulses and the actual time difference tau c And obtaining the time deviation of the measured time signal.
10. The method of claim 9, wherein the measured time signal is collected as a door open signal after peak detection and shaping.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210521890.5A CN114895331A (en) | 2022-05-13 | 2022-05-13 | Time signal measuring device and method based on satellite navigation signals |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210521890.5A CN114895331A (en) | 2022-05-13 | 2022-05-13 | Time signal measuring device and method based on satellite navigation signals |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114895331A true CN114895331A (en) | 2022-08-12 |
Family
ID=82720948
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210521890.5A Pending CN114895331A (en) | 2022-05-13 | 2022-05-13 | Time signal measuring device and method based on satellite navigation signals |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114895331A (en) |
-
2022
- 2022-05-13 CN CN202210521890.5A patent/CN114895331A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100583685C (en) | Method for improving satellite time synchronism pulse keeping performance | |
| CN105867107B (en) | A kind of low power consumption high-precision time dissemination system | |
| CN105049040B (en) | A kind of method that Atomic Clocks Based on Coherent Population Trapping output frequency is corrected using GNSS | |
| CN101807089A (en) | Waveform signal generator with optionally adjustable output signal offset | |
| CN109765583A (en) | A kind of clock synchronizing method based on GNSS receiver pulse per second (PPS) | |
| CN106383438B (en) | One kind taming and dociling clock method based on sliding window time extension high-precision | |
| CN103699001A (en) | Method and system for realizing low-cost and high-precision timing through oven controlled crystal oscillator | |
| CN100535824C (en) | Method of improving satellite time synchronuos pulse holding performance | |
| CN106292268B (en) | Time service terminal device and pulse per second (PPS) based on GNSS receiver tame method | |
| CN102636189B (en) | Measurement signal means for correcting and method for correcting measurement signal | |
| CN111010174B (en) | Method and circuit for improving time-keeping metering precision | |
| CN114895331A (en) | Time signal measuring device and method based on satellite navigation signals | |
| CN115047748B (en) | Time service device and method based on satellite navigation signals | |
| CN110677144B (en) | Crystal oscillator calibration method and system | |
| CN115047749B (en) | Satellite navigation signal-based time keeping device and method | |
| CN114614965B (en) | High-precision time-frequency signal generating device | |
| CN115685725A (en) | Clock calibration device of measuring equipment and measuring equipment | |
| CN101488751B (en) | Measurement system and method for temperature frequency correcting apparatus | |
| CN116299566A (en) | High-precision frequency synchronization method of time service type receiver based on phase accumulator | |
| CN114019563B (en) | Seismic exploration synchronous acquisition method based on GPS and 5G dual-channel high-precision time service | |
| CN114296337A (en) | High-precision time service frequency-granting receiver | |
| US5436936A (en) | Compensation of a clock operating error | |
| CN115856793A (en) | Radar signal frequency deviation estimation compensation method | |
| CN114740260A (en) | Special synchronous acquisition method for detecting and adjusting crystal oscillator output frequency in real time | |
| CN114844619B (en) | Frequency signal generating device and method based on satellite navigation signal |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |