METHOD FOR ONE-SIDED RADIO-BASED DISTANCE MEASUREMENT

Abstract

A method for one-sided radio-based distance measurement. The object is to speed up the determination of the distance between a first object and a second object, to enable greater accuracy and/or to enable or improve the determination, even in the event of interference, particularly in the case of one-sided and/or asymmetric interference in the radio connection. The method is carried out largely without radio signals in a transmission direction. The method includes use of a transit time measurement between the first object and the second object to eliminate the ambiguity of the distance measurement; the distance measurement being carried out on the basis of a change in the phase shift, in particular relative to the frequency change, of the signal propagation from the first object to the second object as a result of a frequency change.

Claims

1. A method for distance determination between at least two objects, wherein the at least two objects are or will be time- or clock-cycle-synchronized, and wherein a first object of the at least two objects emits at least one signal on each of a first frequency and a second frequency, and a second object of the at least two objects receives the at least one signal of the first object and carries out phase measurements on them, wherein the first object changes between the first frequency and the second frequency in a phase-coherent manner with a phase jump of zero, or changes so that upon changing frequencies, the phase jump is known or determined upon transmission, and the distance between the first object and the second object is determined from the phase change caused by the frequency change from the first frequency to the second frequency, and that ambiguity of the distance determination is eliminated by means of a time-of-flight measurement by means of the knowledge of at least one point in time at which the emission of features of the at least one signal took place.

2. A use of a time-of-flight measurement between a first object and a second object for eliminating the ambiguity of a distance measurement, wherein for the purpose of the distance measurement, the first object emits at least one signal on each of a first and a second frequency, wherein the distance measurement is carried out on the basis of the change in the phase shift of the signal propagation from the first object to the second object as a result of a frequency change.

3. The method according to claim 1, wherein for the distance determination, signal components of one or both of the first object and the second object at frequencies with less than 40%, or at least signals with less than 20% of the mean energy of the signals, or signals with more than 140% of the mean energy, remain unconsidered.

4. The method according to claim 1, wherein a plurality of objects carry out the method together.

5. The method according to claim 1, wherein one or both of the first object and the second object emits signals on multiple frequencies successively or consecutively.

6. The method according to claim 1, wherein at least one time- or clock-cycle synchronization or correction is carried out between the at least two objects before, after or while the method is carried out.

7. The method according to claim 5, wherein a frequency spacing between two consecutive frequencies of the multiple frequencies is at least 0.1 MHz or a maximum of 17 MHz, or wherein the multiple frequencies span a frequency band of at least two MHz or a maximum of 100 MHz.

8. The method according to claim 1, wherein the accuracy of the time-of-flight measurement lies in a range from 0.3 m to 3 m.

9. The method according to claim 1, wherein a time drift of at least one or both of the at least two objects, or between the at least two objects, is determined or corrected or is considered in the calculation of the distance.

10. The method according to claim 1, wherein a mean value is determined from multiple distance determinations.

11. The method according to claim 1, wherein signals received at the second object or the first object with a received power below a predetermined or calculated lower power limit are not taken into consideration for the distance determination, and wherein signals received at the second object or the first object with a power above a predetermined or calculated upper power limit are not taken into consideration for the distance determination.

12. The method according to claim 1, carried out between a plurality of pairs of objects, wherein one object of each pair is an object that is involved in all pairs, and wherein the ascertained distances of the pairs are used to carry out a mapping or position determination.

13. An object or an object pair, configured for carrying out the method according to claim 1.

14. The method according to claim 1, wherein at no time the bandwidth of the signals exceeds 50 MHz.

15. The method according to claim 14, wherein at no time the bandwidth of the signals exceeds 25 MHz.

16. The method according to claim 5, wherein the multiple frequencies are at least five frequencies or a maximum of 200 frequencies.

17. The use according to claim 2, wherein for the distance determination, signal components of one or both of the first object and the second object at frequencies with less than 40%, or at least signals with less than 20% of the mean energy of the signals, or signals with more than 140% of the mean energy, remain unconsidered.

18. The use according to claim 2, wherein one or both of the first object and the second object emits signals on multiple frequencies successively or consecutively, wherein a frequency spacing between two consecutive frequencies of the multiple frequencies is at least 0.1 MHz or a maximum of 17 MHz, or wherein the multiple frequencies span a frequency band of at least two MHz r or a maximum of 100 MHz.

19. The use according to claim 2, wherein signals received at the second object or the first object with a received power below a predetermined or calculated lower power limit are not taken into consideration for the distance determination, and wherein signals received at the second object or the first object with a power above a predetermined or calculated upper power limit are not taken into consideration for the distance determination.

20. The use according to claim 2, wherein at no time the bandwidth of the signals exceeds 50 MHz.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] FIG. 1 shows, purely as an example and schematically, an illustration of the change in phase shift due to a frequency change.

[0053] FIG. 2 emphasizes the influence of the phase jump when switching.

DETAILED DESCRIPTION

[0054] FIG. 1 shows, purely as an example and schematically, an illustration of the change in phase shift due to a frequency change. In the upper depiction, a wave at a lower frequency (above) and a wave at a lower frequency (therebelow) is shown between two objects, respectively marked by a vertical line with a distance marked by a double-ended arrow. It is evident that the phase change from the transmitter to the receiver ends up being different at the frequencies. In the lower image, the lower wave is shown phase-shifted in order to also emphasize the change in the received phase based on the transmitted phase.

[0055] FIG. 2 emphasizes the influence of the phase jump when switching. In FIG. 2, an object is respectively shown on the right and left as vertical lines and between them, their distance is illustrated by a double-ended arrow. A phase-coherent frequency switch is illustrated above in FIG. 2, and a switch with phase jump is illustrated below in FIG. 2. It is evident that the phase jump has an effect on the change in phase difference between the phase at the first and at the second object when switching frequencies. This can be mathematically corrected, however, if the phase jump is known.