A time signal measurement device and method based on satellite navigation signal

Abstract

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 gating module, a time difference measurement module and a time difference correction calculation module, the source difference of the local reference signal is measured by receiving the satellite navigation signal, a second pulse to be measured of the measured time signal is used as an opening signal, an adjacent FTF pulse signal generated by the controllable frequency division module is used as a closing signal, the apparent time difference between the two is measured, and the actual time difference corresponding to the apparent time difference is calculated, thereby further obtaining the moment deviation of the measured time signal. The present invention improves the measurement accuracy of the local reference source and the accuracy of the measured time signal by introducing the satellite navigation signal, and has the advantages of high measurement accuracy, low cost, wide application range, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of time-frequency testing, and in particular relates to a time signal measuring device and method based on satellite navigation signals. Background Art

[0002] In the prior art, when using satellite navigation signals to measure time and frequency signals, an independent satellite timing module is usually used to receive satellite navigation signals, measure the deviation of the local reference frequency, record the adjustment information of the local reference source, and tame the local reference source.

[0003] Here, since the independent satellite timing module and the local reference source are of different sources, that is, different reference sources are used, mainly because the satellite timing module uses its own independent reference source. Therefore, the measurement part of the frequency difference between the local reference signal and the satellite navigation signal and the adjustment part of the local reference frequency are of different sources. When measuring time-frequency signals based on this principle, the accuracy is not high, and can only reach 10 -8 Up to 10 -9 There is a phase deviation of the measured time second pulse. Summary of the invention

[0004] The main technical problem solved by the present invention is to provide a time signal measurement device and method based on satellite navigation signals, so as to solve the problems of different sources and low measurement accuracy in time and frequency measurement in the prior art.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is: providing a time signal measurement device based on satellite navigation signals, comprising a local reference source, a signal receiving and source difference measurement module, a controllable frequency division module, a parameter generation module, a delay gating module, a time difference measurement module and a time difference correction calculation module, wherein the local reference source outputs a local reference signal to the signal receiving and source difference measurement module, the signal receiving and source difference measurement module receives a satellite navigation signal, performs source difference measurement on the local reference signal, obtains a source difference value of the local reference signal, and then outputs the local reference signal to the parameter generation module and the time difference correction calculation module;

[0006] The local reference signal is also input into the controllable frequency division module to generate a master clock, the parameter generation module generates an output frequency adjustment value, divides the master clock to generate an FTF pulse signal, and then inputs it into the delay gating module;

[0007] The measured time signal is input into the delay gating module and the time difference measurement module respectively, and a second pulse to be measured of the measured time signal is collected as an opening signal. After the second pulse to be measured appears, the delay gating module collects an adjacent pulse in the FTF pulse signal adjacent thereto as a closing signal, and inputs the closing signal into the time difference measurement module;

[0008] The time difference measurement module accesses the local reference signal of the local reference source and uses it as a reference clock to measure the apparent time difference between the door opening signal and the door closing signal;

[0009] The time difference correction calculation module receives the apparent time difference and the source difference of the local reference signal, calculates the actual time difference corresponding to the apparent time difference, and further obtains the time deviation of the measured time signal.

[0010] Preferably, the signal receiving and source difference measurement module includes a frequency conversion submodule, a demodulation submodule and a source difference calculation module, wherein the frequency conversion submodule calculates the actual frequency value f0' of the local carrier signal after frequency multiplication based on the actual frequency value f0' of the local reference signal. c '=Mf0', where M represents the frequency multiplication value, for the input satellite navigation signal f sz Down-conversion processing is performed to obtain a low intermediate frequency signal which is input into the demodulation submodule, and the frequency conversion submodule also outputs a carrier frequency difference Δf c ', the demodulation submodule uses the local carrier signal to perform carrier loop tracking demodulation to obtain demodulation information, and the demodulation submodule also outputs a tracking frequency difference Δf c ", the carrier frequency difference and tracking frequency difference add Δf c '+Δf c ” = f c '-f sz , and then the source difference calculation module calculates the source difference of the local reference signal Where f0 represents the nominal frequency of the local reference source, f0'=f c ' / M=(Δf c '+Δf c ”+f sz ) / M.

[0011] Preferably, the controllable frequency division module includes a first adder and a delay register, the frequency adjustment value from the parameter generation module is input into the first adder, and is periodically accumulated with the accumulated value stored in the delay register, and after accumulating to one second period, the first adder updates the input frequency adjustment value and continues to accumulate, the first adder is also cascaded with an edge detector for detecting edge transitions of the output waveform, and the edge detector outputs the local second pulse.

[0012] Preferably, the parameter generation module obtains the source difference of the local reference signal The actual frequency of the local reference signal After K times of frequency in the controllable frequency division module, the actual frequency of the main clock generated is Kf0'. x The parameter generation module can calculate the frequency adjustment value to be 2. N / Kf0'T x , N represents the word length of the phase accumulator of DDS.

[0013] Preferably, the time difference measurement 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 of the local reference signal from the signal receiving and source difference measurement module. Further calculate the actual time difference between the door opening signal and the door closing signal And according to the number of FTF pulses between the gate opening signal and the adjacent local second pulses and the actual time difference τ c , and obtain the moment deviation of the measured time signal.

[0014] Preferably, it further comprises a peak detection and shaping module, which performs peak detection and shaping on the input measured time signal and then inputs it into the delay gating module and the time difference measurement module respectively.

[0015] Based on the same concept, the present invention also provides a method for measuring a time signal based on a satellite navigation signal, comprising the steps of:

[0016] receiving a satellite navigation signal, and performing source difference measurement on the local reference signal using the satellite navigation signal to obtain a source difference value of the local reference signal;

[0017] The source difference of the local reference signal is used to adjust the frequency, and the FTF pulse signal and the local second pulse are generated by controllable frequency division;

[0018] A pulse to be measured in the measured time signal is collected as a gate opening signal, and then after the pulse to be measured appears, a pulse in the FTF pulse signal adjacent thereto is collected as a gate closing signal;

[0019] Using the local reference signal as a reference clock, measuring the apparent time difference between the door opening signal and the door closing signal;

[0020] The actual time difference corresponding to the apparent time difference is calculated using the source difference of the local reference signal, thereby further obtaining the time deviation of the measured time signal.

[0021] Preferably, the method of performing source difference measurement on the local reference signal using the satellite navigation signal comprises:

[0022] multiplying the local reference signal to obtain a local carrier signal,

[0023] Demodulating and receiving the satellite navigation signal using the local carrier signal to obtain the actual frequency difference between the local carrier signal and the satellite navigation signal in real time,

[0024] The actual frequency of the local carrier signal is calculated using the actual frequency of the satellite navigation signal and the actual frequency difference, thereby obtaining the actual frequency of the local reference signal.

[0025] A source difference value of the local reference signal is calculated using the actual frequency and the nominal frequency of the local reference signal.

[0026] Preferably, the apparent time difference τ between the door opening signal and the door closing signal is measured p , the source difference of the local reference signal Further calculate the actual time difference between the door opening signal and the door closing signal And according to the number of FTF pulses between the gate opening signal and the adjacent local second pulses and the actual time difference τ c , and obtain the moment deviation of the measured time signal.

[0027] Preferably, the measured time signal is first subjected to peak detection and shaping and then collected as a gate opening signal.

[0028] The beneficial effects of the present invention are as follows: 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 gating module, a time difference measurement module and a time difference correction calculation module, the source difference of the local reference signal is measured by receiving the satellite navigation signal, a second pulse to be measured of the measured time signal is used as an opening signal, an adjacent FTF pulse signal generated by the controllable frequency division module is used as a closing signal, the apparent time difference between the two is measured, and the actual time difference corresponding to the apparent time difference is calculated, thereby further obtaining the moment deviation of the measured time signal. The present invention improves the measurement accuracy of the local reference source and the accuracy of the measured time signal by introducing the satellite navigation signal, and has the advantages of high measurement accuracy, low cost, and wide application range. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the composition of an embodiment of a time signal measuring device based on satellite navigation signals of the present invention;

[0030] Figure 2It is a schematic diagram of the signal receiving and measuring module in another embodiment of the time signal measuring device based on satellite navigation signals of the present invention;

[0031] Figure 3 It is a schematic diagram of the composition of a controllable frequency division module in another embodiment of the time signal measurement device based on satellite navigation signals of the present invention;

[0032] Figure 4 It is a schematic diagram of waveforms generated by a controllable frequency division module in another embodiment of the time signal measurement device based on satellite navigation signals of the present invention;

[0033] Figure 5 It is a schematic diagram of the timing sequence of second time calibration in another embodiment of the time signal measurement device based on satellite navigation signal of the present invention;

[0034] Figure 6 It is a schematic diagram of a time difference measurement timing sequence in another embodiment of a time signal measurement device based on satellite navigation signals of the present invention;

[0035] Figure 7 It is a flow chart of an embodiment of a method for measuring a time signal based on a satellite navigation signal of the present invention. DETAILED DESCRIPTION

[0036] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. Preferred embodiments of the present invention are provided in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0037] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0038] Each embodiment is described in detail below with reference to the accompanying drawings.

[0039] Figure 1 This is a schematic diagram of the composition of an embodiment of a time signal measurement device based on satellite navigation signals. Figure 1It can be seen that it includes a local reference source 11, a signal receiving and source difference measurement module 12, a controllable frequency division module 14, a parameter generation module 13, a delay gating module 16, a time difference measurement module 17 and a time difference correction calculation module 18. The local reference source 11 outputs a local reference signal, which is input to the signal receiving and source difference measurement module 12. The signal receiving and source difference measurement module 12 receives a satellite navigation signal, performs source difference measurement on the local reference signal, obtains a source difference value of the local reference signal, and then outputs it to the parameter generation module 13 and the time difference correction calculation module 18.

[0040] The local reference signal is also input into the controllable frequency division module 14 as the main clock, and the parameter generation module 13 generates an output frequency adjustment value, divides the main clock to generate an FTF (Fundamental time frame) pulse signal, and then inputs it into the delay gating module 16;

[0041] Preferably, in practical applications, the signal receiving and source difference measurement module 12 and the controllable frequency division module 14 can include frequency multipliers, respectively, and the local reference signal input by the local reference source 11 can be frequency multiplied in the signal receiving and source difference measurement module 12 and the controllable frequency division module 14, respectively, and the frequency multiplication value can be different, and frequency synthesis can also be performed based on the local reference signal to generate the required multiple frequency components. However, these frequency components all use the local reference signal as the reference clock, and therefore have the characteristics of the same source, and have the same frequency accuracy of the same source.

[0042] The measured time signal is input into the delay gating module 16 and the time difference measuring module 17 respectively, and a second pulse to be measured of the measured time signal is collected as an opening signal. The delay gating module 16 also collects an adjacent pulse in the FTF pulse signal adjacent to the second pulse to be measured as a closing signal after the second pulse to be measured appears, and inputs the closing signal into the time difference measuring module 17;

[0043] The time difference measurement module 17 receives the local reference signal of the local reference source and uses it as a reference clock to measure the apparent time difference between the door opening signal and the door closing signal;

[0044] The time difference correction calculation module 18 receives the apparent time difference and the source difference of the local reference signal, calculates the actual time difference corresponding to the apparent time difference, and further obtains the measured time difference between the measured time signal and the reference time.

[0045] Preferably, for the signal receiving and source difference measurement module 12, it receives the satellite navigation signal through the satellite antenna, completes the down-conversion and demodulation of the satellite navigation signal, and obtains the satellite navigation signal, and the local reference signal output by the local reference source is used in the receiving process to carry out the carrier loop tracking in the down-conversion and demodulation. Therefore, the signal receiving and source difference measurement module 12 uses the local reference signal output by the local reference source 11 as the source signal for signal reception, and the local reference source 11 in the device also provides the signal source for the controllable frequency division module 14 and the time difference measurement module 17, thereby ensuring that the local reference source 11 in the device is a unified reference source, and ensuring the homology of each module that generates second pulses.

[0046] With the popularization of GPS, Beidou and other satellite navigation and positioning modules and chips, which have lower market prices, the cost of the signal receiving and source difference measurement module 12 will be significantly reduced. At the same time, the accuracy requirements for the local reference source that generates the local reference signal are not high, and only a constant temperature crystal oscillator or a temperature compensated crystal oscillator is required, instead of a more expensive atomic clock, which can also reduce the price.

[0047] For the present invention, the local reference source 11 includes low-cost common reference sources such as quartz crystal, constant temperature crystal oscillator, temperature compensated crystal oscillator, etc. These reference sources may have aging and drift problems, that is, there is a problem of frequency change over time, or a problem of frequency stability. For example, the frequency stability of a quartz crystal can reach 10 -9 / day, even 10 -11 / day, for a 10MHz quartz crystal, the frequency change within a day is generally no more than 0.1Hz. The frequency stability of a quartz crystal is lower than that of an oven-controlled crystal oscillator, which means that the frequency of a quartz crystal changes more or faster than that of an oven-controlled crystal oscillator over time. Therefore, for the frequency dynamic change problem of the reference source, it is necessary to accurately measure its actual frequency value and maintain the dynamic and real-time nature of this measurement.

[0048] The present invention uses the received satellite navigation signal carrier demodulation and telegram ephemeris to obtain the accurate carrier frequency of the satellite navigation signal, with an accuracy of 10 -13 Up to 10 -14 The magnitude of the local reference signal can be obtained by using the high-precision measurement signal. The accuracy can reach 10 -11 Up to 10 -12 Although local reference sources have the problem of low frequency stability and their frequencies drift over time, the method of the present invention can measure their actual frequencies with high precision, thereby obtaining actual frequency measurement values ​​with very high accuracy, and this measurement is real-time.

[0049] Preferably, reference Figure 2 The signal receiving and source difference measurement module includes a frequency conversion submodule 121 and a demodulation submodule 122. The frequency conversion submodule 121 uses a local carrier signal that is multiplied based on the local reference signal to down-convert the input satellite navigation signal to obtain a low-intermediate frequency baseband signal that is input to the demodulation submodule 122. The frequency conversion submodule 121 also outputs a carrier frequency difference. The demodulation submodule 122 uses the local carrier signal to perform carrier loop tracking demodulation to obtain demodulation information. The demodulation submodule 122 also outputs a tracking frequency difference. The carrier frequency difference and the tracking frequency difference are added by an adder 123, and then the source difference value is calculated by a source difference calculation module 124.

[0050] Preferably, for satellite navigation signals, the carrier is usually in the L band. After the frequency conversion submodule 121 receives the local reference signal f0' (actual frequency value) from the local reference source 11, it multiplies the frequency internally to obtain the local carrier signal f c '(actual frequency value), then f c '=Mf0', where M represents the frequency multiplication value, and then with the carrier f of the satellite navigation signal sz Mixing (note that the carrier wave f of the satellite navigation signal here sz is an actual value. Since the satellite navigation signal has a very high accuracy, this frequency value is a high-precision frequency value, which can be accurately obtained through the ephemeris and link calculation in the demodulation information, and also represents the true value of the satellite navigation signal carrier frequency). The low intermediate frequency baseband signal is output to the demodulation submodule 122, and the frequency conversion submodule 121 outputs the carrier f relative to the satellite navigation signal. sz The carrier frequency difference Δf c ', which is equivalent to the coarse frequency difference, the demodulation submodule 122 performs demodulation loop tracking processing on the input low intermediate frequency baseband signal, and further obtains the tracking frequency difference Δf between the local carrier signal and the satellite navigation signal carrier in real time c ”, which is equivalent to the fine frequency difference, and then the carrier frequency difference and the tracking frequency difference are added by the adder 123 to obtain Δf c '+Δf c ", which is equivalent to the addition of the coarse frequency difference and the fine frequency difference, so that the actual frequency difference Δf of the local carrier signal relative to the satellite navigation signal carrier frequency can be obtained c =f c '-f sz =Δf c '+Δf c Here Δf c ' and Δf c " can be a positive value or a negative value, depending on the actual deviation.

[0051] Furthermore, for the local reference source, the frequency of the local reference signal actually outputted should be f0'=f c ' / M=(Δf c '+Δf c ”+f sz ) / M, then the source difference of the local reference signal is Where f0 is the nominal frequency of the local reference source. Figure 2 The source difference of the local reference signal It is calculated and output by the source difference calculation module 124 according to the actual frequency difference output by the adder 123.

[0052] Furthermore, the source difference The output is updated at intervals of seconds, so that the error adjustment of the second clock output of the controllable frequency division module 14 is also performed at intervals of seconds, thereby ensuring that a high-precision second clock output can be obtained without long-term observation.

[0053] Furthermore, Figure 1 The parameter generation module 13 in the source difference The frequency adjustment value required for the controllable frequency division module 14 to output the second pulse is generated. The following further describes how to adjust the frequency according to the source difference value in combination with the composition of the controllable frequency division module 14. Control the output of second pulse.

[0054] Combination Figure 1 For the controllable frequency division module 14, the local reference signal input is multiplied by the internal frequency multiplier as the main clock. The second pulse output can be obtained by controlling the frequency division of the main clock. However, since the accuracy and stability of the local reference signal need to be corrected according to the satellite navigation signal, it is necessary to correct the error according to the obtained source difference. Dynamic correction of the local reference signal is needed to ensure the output of high-precision second pulses.

[0055] Preferably, the controllable frequency division module 14 is a direct digital frequency synthesizer (DDS) as a core device, and the DDS divides the input master clock to obtain a second pulse, or the DDS accumulates at a fixed phase interval to obtain a second period, and the phase interval needs to be adjusted according to the actual frequency of the local reference signal. For example, according to the above, the nominal frequency of the local reference signal is f0, and the source difference value obtained by measurement is Then the actual frequency of the local reference signal After the frequency multiplier, the multiplication value is K, then the actual frequency of the master clock is Kf0'. When the actual frequency Kf'0 of the master clock is used for frequency division, N represents the word length or number of bits of the phase accumulator of the DDS, and the minimum phase interval is 2π / 2 N For example, when you want to divide the main clock by two, the frequency adjustment value is 2 N-1 , the corresponding phase accumulation step is π, when the main clock is divided by four, the corresponding frequency adjustment value is 2 N-2 , the corresponding phase accumulation step is π / 2, and so on.

[0056] Therefore, after obtaining the accurate actual frequency Kf0' of the master clock, a period of T x The periodic pulse output, then the corresponding frequency adjustment value can be calculated to be 2 N / Kf0'T x , the corresponding phase accumulation step is 2π / Kf′0T x .

[0057] Therefore, with the master clock as the clock source, when each master clock cycle accumulates a step Then after A master clock can output a second pulse. However, due to the deviation of the actual frequency f0' of the local reference signal, it is necessary to continuously measure the deviation, that is, to measure and output the source difference once every second. By continuously updating the source difference every second To dynamically adjust the cumulative step interval Figure 1 The parameter generation module 13 in The frequency adjustment value of the DDS in the controllable frequency division module 14 is converted to maintain a high numerical accuracy, for example, a 16-bit to 32-bit binary number is used to represent the frequency adjustment value, wherein The N value represents different binary digits.

[0058] In actual applications, there will be The smaller value, that is, 2 N The value is limited, and The value is larger. In this case, it does not directly generate an output second pulse, but generates a periodic pulse with a shorter output period, that is, the aforementioned generation of a period of T x The periodic pulse output, then the corresponding frequency adjustment value can be calculated to be 2 N / Kf0'T x For example, a 10ms period FTF (Fundamental time frame) pulse, and then select a numbered pulse from every 100 FTF pulses as the local second pulse output.

[0059] Figure 3 and Figure 4 The internal composition and internal waveform generation schematic diagram of the controllable frequency division module 14 are further shown. Preferably, the controllable frequency division module includes a first adder 141 and a delay register 142, the frequency adjustment value from the parameter generation module is input to the first adder 141, and is periodically accumulated with the accumulated value stored in the delay register 142, and after accumulating to a second period, the delay register 142 naturally overflows, and then the first adder 141 updates the input frequency adjustment value and continues to accumulate, and the first adder 141 is also cascaded with an edge detector 144 for detecting the edge transition of the output waveform, and the edge detector 144 outputs a local second pulse.

[0060] Further preferably, the controllable frequency division module also includes a second adder 143 cascaded between the first adder 141 and the edge detector 144, the second adder 143 receives the phase adjustment value output from the signal receiving and source difference measurement module, and adds it to the result output by the first adder 141 and then outputs a local second pulse after edge detection by the edge detector.

[0061] Preferably, the frequency adjustment value from the parameter generation module is input to the first adder 141, and driven by the main clock, it is continuously added to the value accumulated in the delay register 142 and output. Under normal circumstances, after accumulating to a second period, a local second pulse is output, and then the accumulated value in the delay register 142 continues to periodically accumulate the input frequency adjustment value. In each second period, due to the source difference value σ in the signal receiving and source difference measurement module s The frequency adjustment value is corrected continuously, and the output second pulse is more accurate, thereby overcoming the irreconcilable contradiction between the measurement duration and the measurement accuracy in the prior art.

[0062] exist Figure 4 The schematic diagram of the signal waveform T141 of the accumulated value output after passing through the first adder 141 shows that the waveform T141 is a periodically accumulated triangular wave, and the period is one second period. If the waveform T141 is directly edge detected by the subsequent edge detector 144, a local second pulse can be output.

[0063] More preferably, Figure 3A second adder 143 is arranged behind the first adder 141 in the figure. The second adder 143 further adds the accumulated value output by the first adder 141 to the phase adjustment value output by the signal receiving and source difference measurement module, thereby further correcting the phase error of the second pulse output. The phase adjustment value is mainly obtained by detecting the phase jitter that occurs when the local reference signal and the satellite carrier signal are measured for source difference. Correspondingly, Figure 4 , which is a schematic diagram showing a waveform T143 output after passing through the second adder 143 , shows that the waveform T143 is phase-adjusted based on the waveform T141 , and the phase of the waveform T143 is slightly ahead of the phase of the waveform T141 . Figure 4 The figure further shows the edge detection waveform T144 of the waveform T143 after passing through the edge detector 144. By adding the phase adjustment value, the phase of the output second pulse can be further corrected, which is beneficial to eliminate the phase jitter problem in the local reference signal and improve the accuracy of the output second pulse.

[0064] Preferably, in the specific implementation of the controllable frequency division module, the frequency adjustment value is used as the step length, the master clock is used for accumulation, and the natural overflow generates an FTF pulse with a period of 10ms, and then the FTF pulse is counted in a modulo 100 manner, that is, the FTF pulse is cyclically output with numbers 0-99, wherein the FTF pulse numbered 0 is designated as the local second pulse corresponding to the second time. In this way, there are 100 FTF pulses between two adjacent local second pulses.

[0065] Preferably, by demodulating the ephemeris information in the satellite navigation signal, the standard satellite time, i.e., the TOD information and satellite time in the navigation message, can be obtained, and then the satellite time recovered by the source difference measurement module and the local time beat signal generated by the local recovery can be received to obtain the difference between the local time and the satellite time, i.e., the clock difference value. Based on the clock difference value, the phase adjustment value of the controllable frequency division module is input until the clock difference value is close to 0, and it is considered that the phase synchronization between the local time and the satellite time has been established.

[0066] Therefore, combined with Figure 1 and Figure 5After 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. The difference between the local time and the satellite time, i.e. the clock difference value, is input into the controllable frequency division module as the phase adjustment value to adjust the output phase of the local second pulse corresponding to the FTF pulse. This is mainly based on the fact that the FTF pulse is generated by the DDS method driven by the master clock, and its output time is the local master clock time. When it lags behind the real time of the satellite (the minimum accuracy is 1 master clock cycle), the delay can be corrected by the mantissa of the DDS transition edge, that is, the phase is controlled by modifying the value of the accumulated step length at the mantissa of the DDS transition edge. Figure 5 The displayed content can schematically show the correction process of local time relative to satellite time.

[0067] Therefore, the frequency adjustment value output by the parameter generation module determines the accuracy of the output second pulse frequency (or period); the phase adjustment value output by the signal reception and source difference measurement module determines the timing accuracy of the output second pulse.

[0068] Combination Figure 1 and Figure 6 The time difference measurement module 17 uses a second pulse P1 to be measured as the gate opening signal for acquisition. At the same time, the second pulse P1 to be measured is also acquired by the delay gate control module 16. Then, the delay gate control module 16 acquires an adjacent pulse P2 in the input FTF pulse signal as the gate closing signal. That is to say, the adjacent pulse P2 is an FTF pulse immediately following the second pulse P1 to be measured. Figure 6 The FTF pulse numbered 5 is shown in the figure.

[0069] In this way, the time difference measurement module 17 can collect and obtain the door closing signal and the door opening signal in sequence. There is a time difference between the two signals. The measurement of the time difference is based on the local reference signal provided by the local reference source as the reference clock, that is, the local reference signal or the local reference signal after multiplication is used to measure the time difference, which is called the apparent time difference τ p , therefore, the apparent time difference τ p The accuracy is determined by the accuracy of the local reference signal, and the accuracy of the local reference signal is accurately obtained through the aforementioned signal receiving and source difference measurement module.

[0070] Therefore, further, the time difference measurement module 17 obtains the apparent time difference τ p After that, it is input to the time difference correction calculation module 18, which also receives the source difference value of the local reference signal from the signal receiving and source difference measurement module. Further calculate the actual time difference between the second pulse P1 to be measured and the adjacent closing pulse P2

[0071] Further, based on Figure 6 As shown in the figure, it can be seen that the second time corresponding to the second pulse P1 to be measured is relative to the FTF pulse. Since the FTF pulse is a pulse sequence with a period of 10ms, the FTF pulse No. 0 corresponds to the second pulse time. Therefore, the time difference measurement module 17 can further calculate the time deviation of the second pulse P1 to be measured relative to the satellite time. This is because the time difference measurement module 17 receives the FTF pulse from the controllable frequency division module and the local second pulse (PPS), which is the local second pulse that has been calibrated with the satellite time. Figure 6 It can be seen that according to the gate opening signal, that is, the number of FTF pulses between the second pulse P1 to be measured and the adjacent local second pulse and the actual time difference τ c , and obtain the accurate time deviation of the measured time signal.

[0072] like Figure 6 As shown, there are 4 FTF pulse intervals between the second pulse P1 to be measured and the previous adjacent local second pulse P3. According to the actual time difference calculated above Then the time deviation between the measured second pulse P1 and the adjacent local second pulse P3 is 50-τ c Therefore, the accurate time deviation of the measured time signal can be obtained through the time difference correction calculation module 18.

[0073] Further, in Figure 1 The peak detection and shaping module 19 is also included, which mainly detects and shapes the input measured time signal to avoid the peak value of the input measured time signal being too small or too large, and avoids the input of distorted signals or interference signals after the measured time signal is shaped, thereby ensuring the purity of the measured time signal.

[0074] Based on the same concept, the present invention also provides a time signal measurement method based on satellite navigation signals. Figure 7 , including the steps of:

[0075] Step S1: receiving a satellite navigation signal, and using the satellite navigation signal to perform source difference measurement on the local reference signal to obtain a source difference value of the local reference signal;

[0076] Step S2: frequency adjustment is performed using the source difference of the local reference signal, and an FTF pulse signal and a local second pulse are generated through controllable frequency division;

[0077] Step S3: collecting a pulse to be measured in the measured time signal as a gate opening signal, and then collecting a pulse in the FTF pulse signal adjacent to the pulse to be measured as a gate closing signal after the pulse to be measured appears;

[0078] Step S4: using the local reference signal as a reference clock, measuring the apparent time difference between the door opening signal and the door closing signal;

[0079] Step S5: Calculate the actual time difference corresponding to the apparent time difference using the source difference of the local reference signal, thereby further obtaining the time deviation between the measured time signal and the local second time.

[0080] Preferably, the method of performing source difference measurement on the local reference signal using the satellite navigation signal comprises:

[0081] multiplying the local reference signal to obtain a local carrier signal,

[0082] Demodulating and receiving the satellite navigation signal using the local carrier signal to obtain the actual frequency difference between the local carrier signal and the satellite navigation signal in real time,

[0083] The actual frequency of the local carrier signal is calculated using the actual frequency of the satellite navigation signal and the actual frequency difference, thereby obtaining the actual frequency of the local reference signal.

[0084] A source difference value of the local reference signal is calculated using the actual frequency and the nominal frequency of the local reference signal.

[0085] Preferably, the apparent time difference τ between the door opening signal and the door closing signal is measured p , the source difference of the local reference signal Further calculate the actual time difference between the door opening signal and the door closing signal And according to the number of FTF pulses between the gate opening signal and the adjacent local second pulses and the actual time difference τ c , and obtain the accurate time deviation of the measured time signal.

[0086] Preferably, the measured time signal is first subjected to peak detection and shaping, and then collected as a gate opening signal. For details, reference may be made to the above description of the embodiment of the time signal measuring device based on satellite navigation signals, which will not be repeated here.

[0087] Based on the above-mentioned embodiment, the present invention discloses a time signal measurement device and method based on satellite navigation signal, 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 gating module, a time difference measurement module and a time difference correction calculation module, the source difference of the local reference signal is measured by receiving the satellite navigation signal, a second pulse to be measured of the measured time signal is used as an opening signal, an adjacent FTF pulse signal generated by the controllable frequency division module is used as a closing signal, the apparent time difference between the two is measured, and the actual time difference corresponding to the apparent time difference is calculated, thereby further obtaining the moment deviation of the measured time signal. The present invention improves the measurement accuracy of the local reference source and the accuracy of the measured time signal by introducing the satellite navigation signal, and has the advantages of high measurement accuracy, low cost, and wide application range.

[0088] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A time signal measurement device based on satellite navigation signals, characterized in that: It includes a local reference source, a signal receiving and source difference measurement module, a controllable frequency division module, a parameter generation module, a delay gating module, a time difference measurement module and a time difference correction calculation module, wherein the local reference source outputs a local reference signal to the signal receiving and source difference measurement module, the signal receiving and source difference measurement module receives a satellite navigation signal, performs source difference measurement on the local reference signal, obtains a source difference value of the local reference signal, and then outputs the local reference signal to the parameter generation module and the time difference correction calculation module; The local reference signal is also input into the controllable frequency division module to generate a master clock, the parameter generation module generates an output frequency adjustment value, divides the master clock to generate an FTF pulse signal, and then inputs it into the delay gating module; The measured time signal is input into the delay gating module and the time difference measurement module respectively, and a second pulse to be measured of the measured time signal is collected as an opening signal. After the second pulse to be measured appears, the delay gating module collects an adjacent pulse in the FTF pulse signal adjacent thereto as a closing signal, and inputs the closing signal into the time difference measurement module; The time difference measurement module accesses the local reference signal of the local reference source and uses it 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 receives the apparent time difference and the source difference of the local reference signal, calculates the actual time difference corresponding to the apparent time difference, and further obtains the time deviation of the measured time signal.

2. The time signal measuring device based on satellite navigation signal according to claim 1, characterized in that: The signal receiving and source difference measurement module includes a frequency conversion submodule, a demodulation submodule and a source difference calculation module. The frequency conversion submodule calculates the actual frequency value f′ of the local carrier signal after multiplication based on the actual frequency value f′0 of the local reference signal. c =Mf′0, where M represents the frequency multiplication value, for the input satellite navigation signal f sz Down-conversion processing is performed to obtain a low intermediate frequency signal which is input into the demodulation submodule, and the frequency conversion submodule also outputs a carrier frequency difference Δf′ c The demodulation submodule uses the local carrier signal to perform carrier loop tracking demodulation to obtain demodulation information, and the demodulation submodule also outputs a tracking frequency difference Δf c ", the carrier frequency difference and tracking frequency difference add Δf c '+Δf c ” = f c '-f sz , and then the source difference calculation module calculates the source difference of the local reference signal Where f0 represents the nominal frequency of the local reference source, f0'=f c ' / M=(Δf c '+Δf c ”+f sz ) / M.

3. The time signal measuring device based on satellite navigation signal according to claim 2, characterized in that: 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 the accumulated value stored in the delay register. After accumulating to one second period, the first adder updates the input frequency adjustment value and continues to accumulate. The first adder is also cascaded with an edge detector for detecting edge transitions of the output waveform, and the edge detector outputs a local second pulse.

4. The time signal measuring device based on satellite navigation signal according to claim 3, characterized in that: The parameter generation module obtains the source difference of the local reference signal The actual frequency value of the local reference signal After K times of frequency in the controllable frequency division module, the actual frequency of the main clock generated is Kf′0. x The periodic pulse output, then the parameter generation module correspondingly calculates the frequency adjustment value to be 2 N / Kf′0T x , N represents the word length of the phase accumulator of DDS.

5. The time signal measuring device based on satellite navigation signal according to claim 4, characterized in that: The time difference measurement 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 of the local reference signal from the signal receiving and source difference measurement module. Further calculate the actual time difference between the door opening signal and the door closing signal And according to the number of FTF pulses between the gate opening signal and the adjacent local second pulses and the actual time difference τ c , and obtain the moment deviation of the measured time signal.

6. The time signal measuring device based on satellite navigation signal according to claim 5, characterized in that: It also includes a peak detection and shaping module, which performs peak detection and shaping on the input time signal to be measured, and then inputs it into the delay gating module and the time difference measurement module respectively.

7. A time signal measurement method based on satellite navigation signals, characterized in that: Includes steps: Receiving a satellite navigation signal, and using the satellite navigation signal to perform source difference measurement on a local reference signal to obtain a source difference value of the local reference signal; The source difference of the local reference signal is used to adjust the frequency, and the FTF pulse signal and the local second pulse are generated by controllable frequency division; A pulse to be measured in the measured time signal is collected as a gate opening signal, and then after the pulse to be measured appears, a pulse in the FTF pulse signal adjacent thereto is collected as a gate closing signal; Using the local reference signal as a reference clock, measuring the apparent time difference between the door opening signal and the door closing signal; The actual time difference corresponding to the apparent time difference is calculated using the source difference of the local reference signal, thereby further obtaining the time deviation of the measured time signal.

8. The method for measuring time signals based on satellite navigation signals according to claim 7, characterized in that: The method of performing source difference measurement on the local reference signal using the satellite navigation signal comprises: multiplying the local reference signal to obtain a local carrier signal, Demodulating and receiving the satellite navigation signal using the local carrier signal to obtain the actual frequency difference between the local carrier signal and the satellite navigation signal in real time, The actual frequency of the local carrier signal is calculated using the actual frequency of the satellite navigation signal and the actual frequency difference, thereby obtaining the actual frequency of the local reference signal. A source difference value of the local reference signal is calculated using the actual frequency and the nominal frequency of the local reference signal.

9. The method for measuring time signals based on satellite navigation signals according to claim 8, characterized in that: Measure the apparent time difference τ between the door opening signal and the door closing signal p , the source difference of the local reference signal Further calculate the actual time difference between the door opening signal and the door closing signal And according to the number of FTF pulses between the gate opening signal and the adjacent local second pulses and the actual time difference τ c , and obtain the moment deviation of the measured time signal.

10. The method for measuring time signals based on satellite navigation signals according to claim 9, characterized in that: The measured time signal is firstly subjected to peak value detection and shaping and then collected as a gate opening signal.

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