# US 11,442,145 B2 · Signal temporal position determination

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- Number: US 11,442,145 B2
- Document ID: US11442145B2
- Status: Granted
- Kind: B2
- Application number: 16/364,505
- Filed: 2019-03-26
- Published: 2020-10-01
- Granted: 2022-09-13
- Earliest claimed: 2019-03-26
- Assignees: Infineon Technologies AG
- Applicants: Infineon Technologies AG
- Inventors: Paul Meissner; Thomas Gigl
- Web page: https://patentgrep.com/patent/US11442145B2

## CPC

- G01S 7/4808: {Evaluating distance, position or velocity data}
- G01S 7/4804: {Auxiliary means for detecting or identifying lidar signals or the like, e.g. laser illuminators}
- G01S 7/4861: Circuits for detection, sampling, integration or read-out
- G01S 7/4865: Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak (peak detection in noise, signal conditioning G01S7/487)
- G01S 7/487: Extracting wanted echo signals {, e.g. pulse detection}
- G01S 17/10: using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32)
- G01S 17/26: wherein the transmitted pulses use a frequency-modulated or phase-modulated carrier wave, e.g. for pulse compression of received signals
- G01S 17/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46)
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES

## Abstract

A method of determining a temporal position of a received signal within a sample series is disclosed. The method includes sampling a sensor at a sampling frequency to generate the sample series. A matched filter set of matched filters is applied to the sample series to generate a matched filter correlation set of matched filter correlations, wherein impulse responses of respective matched filters correspond to a template signal at the sampling frequency of the sensor shifted by a sub-interval shift. The matched filter correlations are evaluated to determine a received signal sub-interval shift. The temporal position of the received signal within the sample series is determined based on at least the received signal sub-interval shift.

## Claims

### Claim 1

A method of determining a temporal position of a received signal within a sample series, comprising:
sampling a sensor at a sampling frequency to generate the sample series;
applying a matched filter set of matched filters to the sample series to generate a matched filter correlation set of matched filter correlations, wherein impulse responses of respective matched filters correspond to a template signal at the sampling frequency of the sensor shifted by a sub-interval shift;
evaluating the matched filter correlations to determine a received signal sub-interval shift; and
determining the temporal position of the received signal within the sample series based on at least the received signal sub-interval shift.

### Claim 2 (depends on 1)

The method of claim 1, further comprising: generating the respective matched filters by sampling the template signal with the sampling frequency and using a set of different sub-interval shifts for the received matched filters.

### Claim 3 (depends on 2)

The method of claim 2, wherein generating the respective matched filters further comprises: generating the respective matched filters according to an equation comprising:
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wherein:
Ns comprises a count of matched filters of the matched filter set;
n comprises an index of a matched filter within the matched filter set;
i comprises a sample index for n;
sT( . . . ) comprises the template signal at a selected time;
TS comprises a duration of a sample interval of the template signal;
MOS comprises an oversampling ratio relative to the sampling frequency of the sensor; and
sT,i[n] comprises a value of a matched filter at i.

### Claim 4 (depends on 1)

The method of claim 1, further comprising: generating the respective matched filters using a subsample series of samples of an oversampled template of the received signal.

### Claim 5 (depends on 4)

The method of claim 4, wherein generating the respective matched filters further comprises: generating the respective matched filters using an oversampled template of the received signal according to an equation comprising:
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wherein:
Ns comprises a count of matched filters of the matched filter set;
n comprises an index of a matched filter within the matched filter set;
i comprises a sample index for n;
sT( . . . ) comprises the template signal at a selected time;
TS comprises a duration of a sample interval of the template signal;
MOS comprises an oversampling ratio relative to the sampling frequency of the sensor; and
sT,i[n] comprises a value of a matched filter at i.

### Claim 6 (depends on 1)

The method of claim 1, wherein applying the matched filter set to the sample series further comprises:
selecting a window of samples within the sample series; and
applying the matched filter set to the window of samples.

### Claim 7 (depends on 1)

The method of claim 1, wherein the matched filter set further comprises:
a first matched filter that differs from a first adjacent matched filter by a first sub-interval shift distance; and
a second matched filter that differs from a second adjacent matched filter by a second sub-interval shift distance that is different than the first sub-interval shift distance.

### Claim 8 (depends on 1)

The method of claim 1, further comprising: generating the respective matched filters with a matched filter count based at least on a selected resolution of the temporal position of the received signal.

### Claim 9 (depends on 8)

The method of claim 8, further comprising:
receiving a request to determine the temporal position of the received signal with a second selected resolution that is different than the selected resolution; and
responsive to the request, regenerating the respective matched filters with a second matched filter count based at least on the second selected resolution.

### Claim 10 (depends on 1)

The method of claim 1, wherein determining the received signal sub-interval shift further comprises:
identifying a selected matched filter that presents a maximum matched filter correlation among the matched filter correlations of the matched filter set; and
selecting the sub-interval shift of the selected matched filter as the received signal sub-interval shift.

### Claim 11 (depends on 1)

The method of claim 1, wherein determining the received signal sub-interval shift further comprises:
for each respective matched filter, calculating a product of the sub-interval shift of the respective matched filter with a matched filter correlation of the matched filter; and
calculating a sum of the products of the respective matched filters, wherein the sum is normalized by a matched filter correlation sum of the matched filter correlations.

### Claim 12 (depends on 1)

The method of claim 1, wherein:
sampling the sensor further comprises: sampling the sensor at the sampling frequency to generate at least two replicate sample series;
applying the matched filter set to the sample series further comprises: applying the matched filter set to the at least two replicate sample series to generate at least two sets of matched filter correlations; and
determining the received signal sub-interval shift further comprises:
accumulating the at least two sets of matched filter correlations for the at least two replicate sample series; and
evaluating the at least two sets of matched filter correlations accumulated over the at least two replicate sample series to determine the received signal sub-interval shift of the received signal within the sample series.

### Claim 13 (depends on 1)

The method of claim 1, further comprising: determining a signal confidence based at least on a correlation distance between the selected matched filter and the sample series.

### Claim 14 (depends on 13)

The method of claim 13, wherein determining the signal confidence further comprises: determining the correlation distance as a standard deviation of samples of the sample series and corresponding samples of the matched filter.

### Claim 15 (depends on 13)

The method of claim 13, further comprising:
comparing the signal confidence to a signal confidence threshold; and
responsive to the signal confidence failing to satisfy the signal confidence threshold, reporting an absence of the signal.

### Claim 16 (depends on 1)

The method of claim 1, comprising: identifying a median sub-interval offset based on at least a median of respective time shifts corresponding to the respective maximum matched filter correlations among the matched filter set.

### Claim 17

A sensor comprising:
a signal detector to apply a matched filter set of matched filters to a sample series of the sensor at a sampling frequency, wherein respective matched filters correspond to a template signal at the sampling frequency shifted by a sub-interval shift, to identify a received signal sub-interval shift of a received signal within the sample series; and
a temporal position determiner to determine a temporal position of the received signal within the sample series based on at least the received signal sub-interval shift of the received signal within the sample series.

### Claim 18 (depends on 17)

The sensor of claim 17, wherein:
the sample series is stored in a shift register with a sample length;
respective matched filters comprise a filter length of the sample length; and
the signal detector applies the matched filter set to the shift register.

### Claim 19 (depends on 17)

The sensor of claim 17, wherein:
the matched filter set further comprises an evaluator set of evaluators that respectively evaluate the sample series to a matched filter to generate a matched filter correlation; and
the signal detector applies the matched filter set to the sample series by concurrently applying the evaluators to the sample series.

### Claim 20

A time-of-flight device comprising:
an emitter to emit a transmitted signal;
a receiver to receive a reflection of the transmitted signal by sampling a sensor at a sampling frequency to generate a sample series comprising a received signal;
a signal detector to apply a matched filter set of matched filters to the sample series, wherein impulse responses of respective matched filters correspond to a template signal sampled at the sampling frequency and shifted by a sub-interval shift, to identify a received signal sub-interval shift of the received signal within the sample series; and
a time-of-flight determiner that determines a time-of-flight of the transmitted signal based on at least the received signal sub-interval shift of the received signal within the sample series.