METHOD FOR DETERMINING A DISTANCE USING A HIGH-RESOLUTION METHOD BASED ON SIGNAL PROPAGATION TIME MEASUREMENTS

Abstract

The invention relates to a method for determining a distance using a high-resolution method based on signal propagation time measurements. The process of determining distances from wireless signals with a high degree of precision using mathematical methods is known, for example using MUSIC or CAPON or methods such as those from EP 3 564 707, EP 3 502 736 A1, or EP 2 212 705. These methods, however, normally require phase measurements. The aim of the invention is to allow such methods to be used even purely with propagation time measurements. This is achieved in that complex numbers are constructed from propagation time measurements and amplitude mea-surements or power measurements, said complex numbers allowing the use of known methods.

Claims

1. A method for distance determination between two objects on the basis of a plurality of radio signal time-of-flight measurements at a plurality of different frequencies between the two objects, wherein phase values for the plurality of different frequencies or arguments of complex numbers for the plurality of different frequencies, are determined from the radio signal time-of-flight measurements, which as phase measurement values are used in mathematical methods for phase-based distance calculation or arguments of complex numbers in mathematical methods for complex distance calculation, in order to determine a distance between the two objects.

2. The method according to claim 1, wherein amplitude or power measurements on the plurality of different frequencies are performed for the plurality of radio signal time-of-flight measurements, wherein a number that is proportional to the amplitude or power is used as the amplitude or amount of the complex number in known mathematical methods for the phase-based distance determination, in order to determine the distance between the two objects.

3. The method according to claim 1, wherein radio signal times-of-flight of the radio signal time-of-flight measurements at frequencies are used for calculating a phase difference scaled to the spacing of the frequencies of the measurements of the radio signal times-of-flight, and the argument of the complex numbers at a first frequency, or the phase value at the first frequency, is given by phase differences summed up to the first frequency.

4. The method according to claim 2, wherein a vector or an autocorrelation matrix is constructed from the complex numbers, wherein the distance between the two objects is calculated from the vector or the autocorrelation matrix, respectively.

5. The method according to claim 1, wherein for radio signal time-of-flight measurement, at least one radio signal with the plurality of different frequencies is sent from a first object of the two objects to a second object of the two objects, or vice versa, wherein there is phase-coherent switching between at least two of the plurality of different frequencies.

6. The method according to claim 1, wherein the radio signal time-of-flight measurements are only carried out on signals that are sent by a first object of the two objects and received at a second object of the two objects.

7. The method according to claim 1, wherein a first object or a second object of the two objects emits the signals on multiple frequencies successively or consecutively.

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

9. The method according to claim 1, wherein a frequency spacing between two consecutive frequencies of the plurality of different frequencies is at least 0.1 MHz or a maximum of 10 MHz, or wherein the plurality of different frequencies span a frequency band of at least 2 MHz or a maximum of 100 MHz.

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

11. The method according to claim 1, wherein signals received at a second object or a first object of the two objects 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 of the two objects with a power above a predetermined and/or 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 ascertained distances of the pairs are used to carry out a mapping or position determination.

13. A use of phase values obtained computationally from radio signal time-of-flight measurements between two objects on different frequencies for the different frequencies, or arguments of complex numbers for the different frequencies, for determining a spacing between the two objects by means of phase-based spacing calculation methods or spacing calculation methods based on complex numbers.

14. The method according to claim 1, wherein a first object or a second object of the two objects does not send any signals for distance determination, or the second object only sends signals for time- or clock-cycle-synchronization.

15. The method according to claim 3, wherein the radio signal times of flight of the radio measurements come from a plurality of different antenna paths.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] FIG. 1 shows purely schematically, by way of example and in a non-limiting manner, a possible embodiment of the method according to the invention.

DETAILED DESCRIPTION

[0063] The described method begins with transmitting radio signals from Object A to Object B at frequencies f0 to fn. The frequencies are changed between phase-coherently without phase jump. At the receiver as well, the frequencies are changed between phase-coherently without phase jump.

[0064] Time-of-flight and amplitude measurements are performed on the received radio signals at Object B. Equivalent phase shifts are calculated from the times-of-flight, or phase shift changes are calculated by means of these or directly, by means of

dPhase shift(f1,f2)=Pi*(RTT(f3)*c)*dFrequency(f1,f2)/c.

[0065] dPhase shift is a phase shift difference between two frequencies f1 and f2, which have the spacing dFrequency. c is the speed of light and RTT is the doubled signal time-of-flight at the frequency fe, similar to f1 and/or f2.

[0066] On this basis, the phases phi are calculated for all f0 to fn, using

phi(f0)=0

and

phi(fc)=Sum(phi(f0)tophi(fc−1))+dPhase shift(fc−1,fc)

[0067] From this, complex numbers Z(f0) to Z(fn) are obtained with

Amount(Z(fd))=A(fd)

and

Argument(Z(fd))=phi(fd)

[0068] Next, the distance between Object A and B is calculated on the basis of Z(f0) to Z(fn).