TRAVEL TIME MEASUREMENT BASED ON FREQUENCY SWITCHING

Abstract

Method for determining a first virtual frequency switching time between a first frequency of a first signal emitted by a first object having a first phase progression and a first further frequency of a first further signal emitted from the first object. First virtual frequency switching time is determined as a time at which, at a second object, the phase relationship between an interpolated or received phase position of the first signal and an interpolated or received phase position of the first further signal corresponds to a first phase relationship between the first further phase progression and first phase progression.

Claims

1.-17. (canceled)

18. A method for determining at least one first virtual frequency switching time between a first frequency (f1) of a first signal (S1) emitted from a first object and having a first phase progression and at least one first further frequency (f1w.n) of a first further signal (S1w.n) emitted from the first object and having a first further phase progression; wherein the at least one first further phase progression of the at least one first further signal (S1w.n) has a first first phase relationship (phi1.1) to the first phase progression of the first signal (S1) at the first object, wherein the first first phase relationship (phi1.1) is predetermined or known or determined; and wherein the first second phase relationship (phi2.1) is predetermined or known or determined, wherein, from a phase progression received at the second object of the first signal (S1) received at the second object, and of the at least one phase progression of the at least one first further signal (S1w.n) received at the second object, the at least one first virtual frequency switching time (t1.1) is determined as a time, at which, at the second object, the phase relationship between the interpolated or received phase positions of the first and the first further signal (S1, S1w.1) corresponds to the first first phase relationship (phi1.1).

19. The method according to claim 18, wherein a second virtual frequency switching time between a second frequency (f2) of a second signal (S2) emitted by a second object and at least one second further frequency (f2w.n) of a second further signal (S2w.n) emitted by the second object and having a second further phase progression is determined, the at least one second further phase progression of the at least one second further signal (S2w.n) having a first second phase relationship (phi2.1), the first second phase relationship (phi2.1) being predetermined or known or being determined and wherein from a phase progression of the second signal (S2) received at the first object and the at least one phase progression of the at least one second further signal (S2w.n) received at the first object, the at least one second virtual frequency switching time (t2.1) is determined as a point in time at which at the first object the phase relationship between the interpolated or received phase progressions of the second and the first second further signals (S2, S2w.1) corresponds to the first second phase relationship (phi2.1), whereby the second frequency (f2) and the at least one second further frequency (f2w.n) are each higher than 1 MHz,

20. The method according to claim 18, wherein at least two first further signals are emitted from the first object, and wherein two first virtual frequency switching times between the first frequency (f1) and at least two first further frequencies (F1w.n) are determined, wherein first phase relationships (phi1.n) exist between successive first or first further signals at the first object, wherein the first phase relationships (phi1.n) at the first object are predetermined or known or determined, wherein the at least two first virtual frequency switching times (t1.n) are determined from a phase progression received at the second object of the first signal (S1) received at the second object and the phase progressions of the at least two first further signals (S1w.n) received at the second object, each as a time, at which the phase relationship between the interpolated or received phase positions of two signals from the first and the at least two first further signals (S1, S1w.n) at the second object corresponds to the respective first phase relationship (phi1.n) between these signals at the first object; or wherein at least two second further signals are emitted from the second object and at least two second virtual frequency switching times between the second frequency (f2) and at least two second further frequencies (F2w.n) are determined, wherein second phase relationships (phi2.n) exist between successive second or second further signals, wherein the second phase relationships (phi2.n) are predetermined or known or determined, wherein the at least two second virtual frequency switching times (t3.n) are determined from a phase progression received at the first object of the second signal (S2) received at the first object and the phase progressions of the at least two second further signals (S2w.n) received at the first object, each as a time, at which the phase relationship between the interpolated or received phase positions of two signals from the second and the at least two second further signals (S2, S2w.n) at the second object corresponds to the respective second phase relationship (phi2.n) between these signals.

21. The method according to claim 18, wherein the first signal (S1) and the first further signal (S1w) are generated by means of a first single PLL or generated by two first PLLs, between which toggling is done in order to switch the frequency, or wherein the second signal (S1) and at least one second further signal (S1w) is generated by means of a single second PLL or generated by two second PLLs, between which toggling is done in order to switch the frequency.

22. The method according to claim 18, wherein switching or toggling is done at the first object between the emission of the first signal and of the at least one first further signal, or wherein, at the second object, switching or toggling is done between the emission of the second signal and of the at least one second further signal and at least one second further signal.

23. The method according to claim 18, wherein between the end of the first signal (S1) and the beginning of the first further signal (S1w.1) or between the end of the first further signal (S1w.1) and the beginning of a second first further signal (S1w.2), there is a time interval of at most 500 μs, or wherein between the end of the second signal (S2) and the beginning of the second further signal (S1w.1) or between the end of the first second further signal (S2w.1) and the beginning of a second second further signal (S2w.2), there is a time interval of at most five or of at most 500 μs.

24. The method according to claim 18, wherein the first frequency (f1) differs from the at least one first further frequency by a first difference (df1), or the second frequency differs from the at least one second further frequency by a second difference (df2), or wherein the first difference (df1) or the second difference (df1) has a value in the range of 100 kHz multiplied by the phase resolution up to 80 MHz achieved by the number of samplings performed of the first signal (S1) or of at least one first further signal (S1w.n) further signal multiplied by the phase resolution achieved by the number of samplings performed of the first signal (S1) or of at least one first further signal (S1w), or wherein the first difference (df1) differs from the second difference (df2) by at least 10%.

25. The method according to claim 18, wherein at least one first virtual frequency switching time is used for synchronization of the second object or of the first signal received at the second object or of a first further signal; or wherein a first switching time at which the phase relationship between the phase position of the first signal (S1) and the phase position of a first further signal (S1w.n) at the first object corresponds to one of the first phase relationships (phi1.n) has a predetermined or determinable time relationship relative to a signal emitted from the second object.

26. The method according to claim 18, wherein the phase position of the first signal (S1) or at least one of the first further signals (S1w.n) at the second object (receiver) is determined at the virtual frequency switching time (t1), and is used for range finding, or measuring the change in distance between the first and second object.

27. A method for signal round-trip time measurement or signal runtime measurement or for measuring the phase round-trip shift at least between a first object and a second object, including the steps of: a. performing a reference sequence including, at least once, the following steps of: i. sending a reference signal (RS) from the second object to the first object before, at or after a first reference time (t1′); ii. receiving the reference signal (RS) at the first object; wherein, at the second object, a first time difference (dt1) between a virtual frequency switching time (t1) and the reference time (t1′) is predetermined or known or determined; and wherein, at the first object, a second time difference (dt2) between a first switching time at which the phase relationship between the phase position of the first signal (S1) and the phase position of a first further signal (S1w.n) at the first object corresponds to the first phase relationship (phi1), and reception of the reference signal (RS) at the first object is predetermined or known or determined; and calculating a signal round-trip time or signal runtime or phase round-trip shift between the first and second object from the first time difference (dt1) and second time difference (dt2).

28. The method according to claim 27, wherein the reference signal (RS) has a second signal (S2) and at least one second further signals (S2w.n), wherein the second signal (S2) has a second frequency and a second phase progression, and each of the second further signals (S2w.n) has a second further frequency (f2w.n) and a second further phase progression; wherein the at least one second further phase progression of the at least one second further signal (S2w.n) to the respective preceding or following second further phase relationship of the at least one second further signal (S2w.n) or second phase progression of the second signal (S2), wherein the at least one second phase relationship (phi2.n) is predetermined or known or determined; wherein at least one, second virtual frequency switching times (t2.n) are determined from a time phase progression of the second signal (S2) received at the first object and the time phase progression of at least one second further signal (S2w.n) received at the first object further signal, each as a time between the interpolated or received phase positions of two signals from the second and the second further signals (S2, S2w.n) corresponding to the respective second phase relationship (phi2.n) between these signals; and wherein at the first reference time (also, second switching time) (t1′) the phase relationship between the phase position of the second signal (S2) and the phase position of at least one second further signal (S2w.n) at the second object corresponds to the second phase relationship (phi2.n) between these signals.

29. The method according to claim 27, wherein the phase relationship at the second object between reference signal (RS), second signal (S2) or second further signal (S2w), and first signal (S1) or the phase relationship between reference signal (RS) and first further signal (S1w) is determined or predetermined, or wherein the phase relationship at the first object between reference signal (RS), and first signal (S1) or the phase relationship between reference signal (RS), and first further signal (S1w) is determined or predetermined.

30. The method according to claim 27, wherein, after a first signal (S1), a first further signal (S1w) is emitted several times in succession, or wherein a first signal (S1) and a first further signal (S1w) are emitted several times in succession, or wherein after a second signal (S2) a second further signal (S2w) is emitted several times in succession or wherein a second signal (S2) and a second further signal (S2w) are emitted several times in succession switching on or switching off an amplifier at the first or second object.

31. The method according to claim 27, wherein among several possible first virtual frequency switching times, the first virtual frequency switching time (t1) is determined according to the same rule as the first switching time (t1′) among several possible switching times, or among several possible first virtual frequency switching times, the one or a middle one is determined as the first virtual frequency switching time (t1), and among several possible first switching times, the or a middle one is determined as the first switching time (t1′), or wherein, among several possible first virtual frequency switching times, the one, which lies at the same position in the signal progression of the first signal (S1) and first further signal (S1w) as the first switching time (t1′) is determined as the first virtual frequency switching time (t1′).

32. A use of at least one first virtual frequency switching time (t1) between a first frequency (f1) of a first signal (S1) having a first phase progression emitted from a first object (emitter) and at least one first further frequency (f1w.n) of at least one first further signal (S1w.n) emitted from the first object and having a first further phase progression, and a reference time, wherein a reference signal is sent from a second object such that it exhibits a change at the reference time, in order to determine a time, a distance, a runtime or for synchronizing two time measurements; wherein the first phase progression of the first signal (S1) has a first first phase relationship (phi1.1) to the first further phase progression of the first first further signal (S1w.n) at the first object, wherein the first first phase relationship (phi1.1) is predetermined or known or determined; and wherein from a phase progression received at a second object of the first signal (S1) received at the second object and the phase progression of the first first further signal (S1w.1) received at a second object, the at least one first virtual frequency switching time (t1) is determined as a time, at which the phase relationship between the interpolated or received phase positions of the first and the first further signal (S1, S1w.1) corresponds to the first first phase relationship (phi1.1).

33. The use according to claim 32, wherein the first frequency (f1) and the at least one first further frequency (f1w.n) and the second frequency (f2) and the at least one second further frequency (f2w.n) are each higher than 1 MHz.

34. The use according to claim 32, wherein the reference signal is sent before or after the reference time (t1′), or that the change at the reference time is a frequency change, phase change, edge or frequency switch.

35. The use according to claim 32, wherein the first signal (S1) and the first further signal (S1w) are generated by means of a first single PLL or by two first PLLs, which are toggled in order to switch the frequency, or wherein the second signal (S1) and the second further signal (S1w) are generated by means of a single second PLL or by two second PLLs, which are toggled in order to switch the frequency.

36. The use according to claim 32, wherein, at the first object, switching or toggling is done between the emission of the first signal and of the at least one first further signal, or wherein, at the second object, switching or toggling is done between the emission of the second signal and of the at least one second further signal.

37. The use according to claim 32, wherein between the end of the first signal (S1) and the beginning of the first further signal (S1w.1) or between the end of the first first further signal (S1w.1) and the beginning of a second first further signal (S1w.2), there is a time interval of at most 500 μs, or wherein between the end of the second signal (S2) and the beginning of the second further signal (S1w.1) or between the end of the first second further signal (S2w.1) and the beginning of a second second further signal (S2w.2), there is a time interval of at most five, in particular at most two, periods of the first or of the first further signal or of at most 500 μs.

38. The use according to claim 32, wherein the first frequency (f1) differs from the at least one first further frequency by a first difference (df1) or the second frequency differs from the at least one second further frequency by a second difference (df2), wherein in particular the first difference (df1) or the second difference (df1) has a value of at least 0.02‰, in particular at least 0.04‰, of the frequency of the first or first further signal or of at least 50 kHz, in particular at least 100 kHz, or of at most 5%, of the frequency of the first or first further signal or of at most 120 MHz, or where the first difference (df1) or the second difference (df1) has a value in the range of 100 kHz multiplied by the phase resolution up to 80 MHz achieved by the number of samplings performed of the first signal (S1) or at least one first further signal (S1w.n) or wherein the first difference (df1) differs from the second difference (df2) by at least 10%.

39. The use according to claim 32, wherein at least one first virtual frequency switching time or wherein a first switching time, at which the phase relationship between the phase position of the first signal (S1) and the phase position of a first further signal (S1w.n) at the first object corresponds to one of the first phase relationships (phi1.n), has a predetermined or determinable time relationship relative to a signal emitted from the second object.

40. A device set up for determining at least one first virtual frequency switching time (t1) and sending a second signal and at least one second further signal, and set up for synchronization, for signal round-trip time measurement or signal runtime measurement or for measuring the phase round-trip shift or for range finding or measuring a distance change, having at least one means for receiving a first signal (S1) and at least one first further signal, and for sending a second signal and at least one second further signal from a first object, set up for determining at least one virtual frequency switching time between a first frequency (f1) of the first signal (S1) and at least one first further frequency (f1w.n) of the at least one first further signal (S1w.n); wherein the at least one first further phase progression of the at least one first further signal (S1w.n) has a first first phase relationship (phi1.1) to the first phase progression of the first signal (S1) at the first object, and wherein the device is set up to determine from a phase progression of the first signal (S1) received at the device, and of the at least one phase progression of the at least one first further signal (S2w.n) received at the device, the at least one virtual frequency switching time (t1.1) as a time, at which, at the device, the phase relationship between the interpolated or received phase positions of the first and the first further signal (S1, S1w.1) corresponds to the first first phase relationship (phi1.1).

41. A device set up to emit a first signal (S1) and at least one first further signal (S1w.n) for signal round-trip time measurement or signal runtime measurement or for measuring the phase round-trip shift or for range finding, having at least one PLL for generating the first signal (S1) at a first frequency and the at least one first further signal (S1w) at a first further frequency, wherein the device is set up to toggle between the generation of the first signal (S1) and the generation of the at least one first further signal (S1w.n) using knowledge or determination of the phase difference (phi1.n) between the first signal (S1) and the first further signal (S1w.n), and wherein the device is set up to receive a second signal (S2) from a second object and at least one second further signal from said second object, and is set up to determine at least one virtual frequency switching time between a second frequency (f2) of the second signal (S2) and at least one second further frequency (f2w.n) of the at least one second further signal (S2w.n); wherein the at least one second further phase progression of the at least one second further signal (S2w.n) has a first second phase relationship (phi2.1) to the second phase progression of the second signal (S2) at the second object; and wherein the device is set up to determine from a phase progression of the second signal (S2) received at the device, and of the at least one phase progression of the at least one second further signal (S2w.n) received at the device, the at least one virtual frequency switching time (t2.1) as a time, at which, at the device, the phase relationship between the interpolated or received phase positions of the second and the second further signal (S2, S2w.1) corresponds to the first second phase relationship (phi2.1).

42. A system for synchronization, for signal round-trip time measurement or signal runtime measurement or for measuring the phase round-trip shift or for range finding or measuring a distance change consisting of at least one first and one second device; wherein the first device is set up to emit a first signal (S1) and at least one first further signal (S1w.n), having at least one PLL for generating the first signal (S1) at a first frequency and the at least one first further signal (S1w) at a first further frequency; wherein the first device is set up to toggle between the generation of the first signal (S1) and the generation of the at least one first further signal (S1w.n) using knowledge or determination of the phase difference (phi1.n) between the first signal (S1) and the first further signal (S1w.n); wherein the at least one first further phase progression of the at least one first further signal (S1w.n) has a first first phase relationship (phi1.1) to the first phase progression of the first signal (S1) at the first device, wherein first device is set up to predetermine, determine or know the first first phase relationship (phi1.1); and wherein the first device is set up to receive a second signal (S12) from the second device and at least one second further signal from said second device, and is set up to determine at least one virtual frequency switching time between a second frequency (f2) of the second signal (Ss2) and at least one second further frequency (f2w.n) of the at least one second further signal (S2w.n); wherein the first device is set up to determine from a phase progression of the second signal (S2) received at the first device, and of the at least one phase progression of the at least one second further signal (S2w.n) received at the first device, the at least one virtual frequency switching time (t2.1) as a time, at which, at the first device, the phase relationship between the interpolated or received phase positions of the second and the second further signal (S2, S2w.1) corresponds to the first second phase relationship (phi2.1); wherein the second device is set up to emit the second signal (S2) and the at least one second further signal (S2w.n), having at least one PLL for generating the second signal (S2) at the second frequency and the at least one second further signal (S2w) at the second further frequency; wherein the second device is set up to toggle between the generation of the second signal (S2) and the generation of the at least one second further signal (S2w.n); wherein the at least one second further phase progression of the at least one second further signal (S2w.n) has a first second phase relationship (phi2.1) to the second phase progression of the second signal (S2) at the second device; and wherein second device is set up to predetermine, determine or know the first second phase relationship (phi2.1) and is set up to determine from a phase progression of the first signal (S1) received at the second device, and of the at least one phase progression of the at least one first further signal (S2w.n) received at the second device, the at least one virtual frequency switching time (t1.1) as a time, at which, at the second device, the phase relationship between the interpolated or received phase positions of the first and the first further signal (S1, S1w.1) corresponds to the first first phase relationship (phi1.1).

Description

[0113] Further advantages and features of the invention will become clear from the following description of an exemplary embodiment with reference to the accompanying drawings. In the drawings:

[0114] FIG. 1 is an illustration of the switching between two PLLs,

[0115] FIG. 2 is an illustration for determining multiple virtual frequency switching times,

[0116] FIG. 3 is an illustration for determining a virtual frequency switching time with phase offset,

[0117] FIG. 4 is an illustration of a first signal and a first further signal together with the binary signal used for generation,

[0118] FIG. 5 is an illustration of a first signal and a first further signal together with the binary signal used for generation,

[0119] FIG. 6 is an illustration for determining a virtual frequency switching time,

[0120] FIG. 7 is an illustration of a signal round-trip time measurement,

[0121] FIG. 8 is an illustration of two signal round-trip time measurements, and

[0122] FIG. 9 is an illustration of a sequence of several following first and following second signals for measuring the signal round-trip time.

[0123] FIG. 1 shows two PLLs, which can emit their output signal via an amplifier to an antenna by means of a downstream switch. Only the signal of one PLL may be forwarded. Each of the PLLs can be set to different frequencies.

[0124] Furthermore, a control system is shown, which is configured to evaluate the phases of the signals of the PLLs and calculate a switching time, at which the switch is being activated and resulting in a continuous phase-coherent signal. In particular, switching elements designed as semiconductors are used as switches, e.g., transistors or MOSFETs.

[0125] FIG. 2 shows phase measurements on a first signal (S1) (three marks on the left) and on three first further signals (S1w.1-S1w.3) (next three marks) with different frequencies (f1, f1w.1-f1w.1-f1w.3) received at a second object after being emitted from a first object, plotted against time, including extrapolations of the measured values based on interpolation, as straight lines. The intersection points of the straight lines are each indicated by a vertical dashed line, which marks the first virtual frequency switching time (dashed line on the left), and further virtual frequency switching times (following dashed lines), which can each be determined in this way assuming phase-coherent switching (first and further phase differences each equal zero).

[0126] FIG. 3 shows phase measurements on a first signal (left three marks) and on a first further signal (three marks on the right) plotted against time, as well as extrapolations of the measured values based on interpolation, as straight lines. The vertical dashed line indicates the first virtual frequency switching point, which may be determined in this way assuming toggling with a first phase difference represented by the double arrow (first phase difference < >0).

[0127] FIG. 4 shows a binary signal on top, and a frequency shift keyed signal below by coherent switching between two PLLs tuned to different frequencies. Below this, the resulting signal is characterized as a repeating sequence of first and further first signals. In principle, in the case of repetitions (including with different frequencies), the switch between the first further frequency to the first frequency is also advantageously evaluated, e.g., by performing the method on the assumption that the first further signal represents the first signal and the first signal following this represents the first further signal.

[0128] FIG. 5 shows an illustration similar to FIG. 4, with the difference that each switching (frequency shift keying) requires a minor time gap and a predetermined phase jump.

[0129] FIG. 6 shows an alternative determination of a first virtual frequency switching time with phase-coherent switching. The upper line shows samplings at the first signal (left seven marks) and samplings at the first further signal (seven marks on the right) shown over time from left to right. The variation over time of the first signal (left) and the first further signal (right) is illustrated as solid lines. No signal is present or no signal is received in the area of the continued dashed line. The dashed lines can be determined by extrapolating by an equalization calculation on the sampling d values of the first signal or the first further signal. Thus, the first virtual frequency switching time, indicated by a vertical dashed line, may be determined. Note that not every contact of the dashed lines represents a virtual frequency switching time, since the phase position must be identical.

[0130] The results of the equalization calculation and the extrapolations are shown separately.

[0131] FIG. 7 again shows the phase plotted against time. Two temporal axes can be seen, one for the time period at the first object, t.sub.O1, and one for the second at the second object, t.sub.O2; the signals emitted from the first object and received at the second object (first signal and first further signal), at which the second object takes phase measurements (dashed measuring points), are shown on the left. The first object has switched or changed the frequency without a phase jump at the time t.sub.U1.1. From the measuring points of the phase measurements of the second object, the corresponding virtual frequency switching time t.sub.1.1 can be determined. According to the above explanations, this is also feasible with other types of switching, e.g., interruption of the emission and/or a phase jump. Subsequently, the signal emitted from the second object is received at the first object, as are the second signal and the second further signal. Thus, the second object has changed frequency in a phase coherent manner at the time t.sub.U2.1. The first object takes phase measurements on the signals (measuring points on the right in the figure). From this, the corresponding second virtual frequency switching time can be determined.

[0132] From the first interval determined at the first object from t.sub.U1.1 to t.sub.2.1 and the second interval determined at the second object from t.sub.1.1 to t.sub.U2.1, the signal round-trip time can be calculated by subtracting the second interval from the first. This will now be explained again in more detail with reference to the following drawings.

[0133] FIG. 8 shows the scenario depicted in FIG. 7 on the left. The slanted dashed arrows illustrate the radio transmission, first from the first object to the second object, and then from the second object to the first object. However, at the indicated points in time, e.g., t.sub.U1.1, no pulse is emitted, however, the toggling is situated there, such that if the frequency change along with an interruption at this time, no signal whatsoever is emitted. The arrows between the temporal axes are thus more apt to illustrate the transmission than represent an actual signal. The first and second time differences explained above are indicated as time intervals, each with a double arrow. it can be seen that their difference coincides with the sum of the signal runtimes. These signal runtimes are again illustrated above the upper time line as dashed double arrows parallel to the time line. In the further course of time, i.e., in the figure further to the right, a further implementation of the scenario from FIG. 7 is shown, which is carried out in particular with other frequencies. For example, the accuracy may be increased or ambiguities may be avoided for range finding based on phase shifts, if the measurements are evaluated in combination. However, it is preferable not to carry out the implementations sequentially in a time-separated manner, as in FIG. 8, but to work with several consecutive first signals and several consecutive second further signals, as illustrated, e.g., in FIG. 9.

[0134] FIG. 9 shows in the notation from FIG. 8, an implementation with a first signal and three first further signals and a second signal and three second further signals, in which three first switching times or switching times t.sub.U1.n, three first virtual frequency switching times t.sub.1.n, three second switching times or toggling times t.sub.U2.n and three second virtual frequency switching times t.sub.2.n are present. It can be seen that the time interval between the first virtual frequency switching time and the first second frequency-toggling time (lowest double arrow in FIG. 9) is roughly the same as the time interval between the second virtual frequency switching time and the second frequency-toggling time (third double arrow from the bottom in FIG. 9), while the time interval between the third first virtual frequency switching time and the third second frequency switching time (second double arrow from the bottom in FIG. 9) is substantially greater. This should make it obvious that the length of these time intervals is unimportant, they only need to be known (predetermined or measured).

[0135] Three signal round-trip times can now be determined directly from these measurements. However, by calculating further time intervals between the respective points in time drawn on a time line, further signal round-trip times can also be determined.

[0136] This determination, however, makes it possible to now synchronize or correct the clocks or times of the two objects with a very high degree of accuracy. From the signal round-trip time (averaged from several determinations, as needed), the signal runtime may be determined by way of halving. Thus, for example, the second object can determine the exact position of the time t.sub.U1.1 on the first object on its second-object clock by subtracting the signal runtime (half the round-trip time) from the time t.sub.1.1. This means that the clock on the second object can now also be synchronized with the first object clock with great accuracy. Thus, with certain hardware, a time alignment may be done, which is far more accurate than was previously feasible with the prior-art methods