Method for cyclically measuring distances and velocities of objects using an FMCW radar sensor

1. A method for cyclically measuring distances and relative velocities of at least one object using an FMCW radar sensor, comprising:

periodically modulating the frequency of a transmitted signal of the radar sensor, each period including at least two differing modulation patterns;

deriving a relationship between distance and velocity of the object from a signal received for a single modulation pattern; and

adjusting the signals received, each of the received signals corresponding to a respective one of multiple modulation patterns, to one another in order to determine one value each for the distance and the velocity per each measuring cycle, wherein, for the adjustment between a signal obtained for a modulation pattern in a current measuring cycle and signals obtained for other modulation patterns, at least one signal from at least one previous measuring cycle is utilized.

2. The method as recited in claim 1 , wherein each modulation pattern includes a sequence of modulation ramps having the same lift and the same duration.

3. The method as recited in claim 2 , wherein a set of ambiguous values is determined for the velocity from the signal for a single modulation pattern based on phase differences between the signals which correspond to the consecutive frequency ramps, and the ambiguity is eliminated by adjusting the signals obtained from different modulation patterns.

4. The method as recited in claim 3 , wherein the number of the different modulation patterns is at least three per modulation period.

5. The method as recited in claim 4 , wherein each of the at least three different modulation patterns is followed directly by a respective computing time interval.

6. The method as recited in claim 5 , wherein:

each period includes at least N differing modulation patterns,

the adjustment is performed for signals received over a period according to the N−1 previous measuring cycles and the current measuring cycle, and

in each of the measuring cycles for the period, the signals received relate to a different one of the N modulation patterns.

7. The method as recited in claim 3 , wherein the transmitted signal is modulated within each measuring cycle according to exactly one modulation pattern.

8. The method as recited in claim 1 , wherein the adjustment between the signal obtained for the modulation pattern in the current measuring cycle and the signals obtained for other modulation patterns is performed by determining where a linear relationship between velocity and distance for each of the multiple modulation patterns match.

9. The method as recited in claim 1 , wherein the frequency is modulated by chirp sequence modulation.

10. An FMCW radar sensor, comprising:

an oscillator generating a transmitted signal;

a frequency modulation device modulating the frequency of the transmitted signal;

a mixer mixing the transmitted signal with a signal

received after a reflection from an object to generate a mixed signal; and

a control and evaluation unit evaluating the mixed signal,

wherein the control and evaluation unit is configured to:

periodically modulate the frequency of the transmitted signal of the radar sensor, each period including at least two differing modulation patterns;

derive a relationship between distance and velocity of the object from a signal received for a single modulation pattern; and

adjust the signals received, each of the received signals corresponding to a respective one of multiple modulation patterns, to one another in order to determine one value each for the distance and the velocity per each measuring cycle, wherein, for the adjustment between a signal obtained for a modulation pattern in a current measuring cycle and signals obtained for other modulation patterns, at least one signal from at least one previous measuring cycle is utilized.