Electromagnetic wave-based speed assessment method, system and processor thereof

Abstract

An electromagnetic wave-based speed estimation method includes the steps of: estimating a detected speed based on electromagnetic wave information; and, based on the electromagnetic wave information indicating two movement patterns associated with two correlation characteristic values ​​of a plurality of subcarriers at two time points, generating a first signal to indicate that an identified speed equals the detected speed if the two movement patterns are determined to be the same, and generating a second signal to indicate that the identified speed is greater than the detected speed if the two movement patterns are determined to be different. This improves the speed measurement range without increasing the sampling rate. An electromagnetic wave-based speed estimation system and its processor are also disclosed.

Claims

1. A velocity estimation system based on electromagnetic waves, comprising: An electromagnetic transceiver configured to collect electromagnetic information associated with electromagnetic waves transmitted to and reflected from a target, the electromagnetic waves being associated with an orthogonal frequency division multiplexing (OFDM) protocol; a velocity estimation module configured to estimate a detection velocity based on the electromagnetic information; and a velocity discrimination module configured to generate a first signal indicating an identification velocity equal to the detection velocity in response to the determination that the two mobility modes are the same, and a second signal indicating that the identification velocity is greater than the detection velocity in response to the determination that the two mobility modes are different.

2. The electromagnetic wave-based speed estimation system as claimed in claim 1, wherein the speed identification module is configured to estimate a speed limit based on a wavelength and a sampling rate indicated by the electromagnetic wave information; and in response to the determination that the two movement modes are different, the identified speed is estimated to be twice the speed limit minus a difference of the detected speed.

3. The electromagnetic wave-based speed estimation system as described in claim 2, wherein the speed discrimination module is configured to estimate the upper limit of the speed measurement, as follows: , where, Vmax is the upper limit of the velocity measurement, is the wavelength, and is the sampling rate.

4. The electromagnetic wave-based velocity estimation system as claimed in claim 1, wherein the velocity discrimination module is configured to: indicate that the two movement modes are the same when it is determined that each of the two correlation feature values ​​is greater than or equal to a correlation threshold; indicate that the two movement modes are the same when it is determined that each of the two correlation feature values ​​is less than the correlation threshold; and indicate that the two movement modes are different when it is determined that one of the two correlation feature values ​​is greater than or equal to the correlation threshold and the other is less than the correlation threshold.

5. The electromagnetic wave-based velocity estimation system as claimed in claim 4, wherein the velocity discrimination module is configured to: indicate that the two movement modes jointly represent near to near in response to the determination that each of the two correlation feature values ​​is greater than or equal to the correlation threshold; indicate that the two movement modes jointly represent far to far in response to the determination that each of the two correlation feature values ​​is less than the correlation threshold; and indicate that the two movement modes jointly represent near to far or far to near in response to the determination that one of the two correlation feature values ​​is greater than or equal to the correlation threshold and the other is less than the correlation threshold.

6. The electromagnetic wave-based velocity estimation system as claimed in claim 1, wherein the velocity discrimination module is configured to estimate the two correlation feature values ​​based on a plurality of subcarrier index values ​​at two time points indicated by the electromagnetic wave information, each of the two correlation feature values ​​being calculated as follows: , where, Let f be the correlation characteristic value, f represent one of the complex subcarrier index values, is the number of subcarriers, and is the correlation between the f-th subcarrier and the (f+1)-th subcarrier.

7. The electromagnetic wave-based velocity estimation system as described in claim 6, wherein the velocity discrimination module is configured to: calculate a correlation coefficient between a first subcarrier and a second subcarrier to represent the correlation between the f-th subcarrier and the (f+1)-th subcarrier, the correlation coefficient being calculated as follows: , , , where, X is the first subcarrier containing N samples over a period of time, Y is the second subcarrier containing N samples over the same period of time, and are the average values ​​of the samples, i is the sample index value, and r is the correlation coefficient between the first subcarrier and the second subcarrier.

8. The electromagnetic wave-based speed estimation system as claimed in claim 1, wherein the speed identification module is configured to: generate a third signal to indicate that the target is in a high-speed state in response to determining that the identified speed is greater than or equal to a speed threshold; and generate a fourth signal to indicate that the target is in a low-speed state in response to determining that the identified speed is less than the speed threshold.

9. A processor suitable for an electromagnetic wave-based speed estimation system, the speed estimation system including an electromagnetic wave transceiver configured to collect electromagnetic wave information associated with electromagnetic waves transmitted to a target and electromagnetic waves reflected from the target, the electromagnetic waves being associated with an orthogonal frequency division multiplexing (OFDM) protocol, wherein the processor is configured to execute at least one instruction associated with a memory to: estimate a detection speed based on the electromagnetic wave information; and indicate two movement modes associated with two correlation characteristic values ​​of a plurality of subcarriers at two time points based on the electromagnetic wave information, indicating an identification speed equal to the detection speed in response to the determination that the two movement modes are the same, and indicating that the identification speed is greater than the detection speed in response to the determination that the two movement modes are different.

10. The processor as claimed in claim 9, wherein the processor is configured to estimate a speed limit based on a wavelength and a sampling rate indicated by the electromagnetic wave information, and to estimate the identification speed as twice the speed limit minus a difference in the detection speed in response to the determination that the two movement modes are different.

11. The processor of claim 9, wherein the processor is configured to: indicate that the two movement modes are the same in response to determining that each of the two correlation feature values ​​is greater than or equal to a correlation threshold; indicate that the two movement modes are the same in response to determining that each of the two correlation feature values ​​is less than the correlation threshold; and indicate that the two movement modes are different in response to determining that one of the two correlation feature values ​​is greater than or equal to the correlation threshold and the other is less than the correlation threshold.

12. The processor as claimed in claim 9, wherein the processor is configured to: estimate the two correlation feature values ​​based on a plurality of subcarrier index values ​​at two time points indicated by the electromagnetic wave information, each of the two correlation feature values ​​being calculated as follows: , where, Let f be the correlation characteristic value, f represent one of the complex subcarrier index values, is the number of subcarriers, and is the correlation between the f-th subcarrier and the (f+1)-th subcarrier.

13. A velocity estimation method based on electromagnetic waves, applied to a system including an electromagnetic transceiver and a processor, the electromagnetic transceiver being configured to collect electromagnetic wave information associated with electromagnetic waves transmitted to a target and electromagnetic waves reflected from the target, the electromagnetic waves being associated with an orthogonal frequency division multiplexing (OFDM) protocol, the method comprising: The processor is configured to execute at least one instruction associated with a memory, the processor performing a speed estimation operation, including: estimating a detection speed based on the electromagnetic wave information; and indicating two mobility modes associated with two correlation characteristic values ​​of a plurality of subcarriers at two time points based on the electromagnetic wave information, indicating an identification speed equal to the detection speed if the two mobility modes are determined to be the same, and indicating an identification speed greater than the detection speed if the two mobility modes are determined to be different.

14. The electromagnetic wave-based speed estimation method as described in claim 13, wherein the processor performs the speed estimation operation, further comprising: Based on the wavelength and sampling rate indicated by the electromagnetic wave information, an upper limit for speed measurement is estimated. In order to determine that the two movement modes are different, the identification speed is estimated to be twice the upper limit for speed measurement minus the difference in the detection speed.

15. The electromagnetic wave-based speed estimation method as described in claim 14, wherein the processor performs the speed estimation operation, further comprising: Estimate the upper limit of the velocity measurement as follows: , where Vmax is the upper limit of the velocity measurement, is the wavelength, and is the sampling rate.

16. The electromagnetic wave-based speed estimation method as described in claim 13, wherein the processor performs the speed estimation operation, further comprising: If each of the two correlation feature values ​​is greater than or equal to a correlation threshold, it indicates that the two movement patterns are the same; if each of the two correlation feature values ​​is less than the correlation threshold, it indicates that the two movement patterns are the same; if one of the two correlation feature values ​​is greater than or equal to the correlation threshold and the other is less than the correlation threshold, it indicates that the two movement patterns are different.

17. The electromagnetic wave-based speed estimation method as described in claim 16, wherein the processor performs the speed estimation operation, further comprising: If each of the two correlation feature values ​​is greater than or equal to the correlation threshold, the two movement patterns are indicated to jointly represent movement from near to near; if each of the two correlation feature values ​​is less than the correlation threshold, the two movement patterns are indicated to jointly represent movement from far to far; if one of the two correlation feature values ​​is greater than or equal to the correlation threshold and the other is less than the correlation threshold, the two movement patterns are indicated to jointly represent movement from near to far or from far to near.

18. The electromagnetic wave-based speed estimation method as described in claim 13, wherein the processor performs the speed estimation operation, further comprising: Based on the electromagnetic wave information indicating the multiple subcarrier index values ​​at two time points, the two correlation characteristic values ​​are estimated. The formula for each of the two correlation characteristic values ​​is as follows: , where is the correlation characteristic value, f represents one of the multiple subcarrier index values, is the number of subcarriers, and is the correlation between the f-th subcarrier and the (f+1)-th subcarrier.

19. The electromagnetic wave-based speed estimation method as described in claim 18, wherein the processor performs the speed estimation operation, further comprising: Calculate a correlation coefficient between a first subcarrier and a second subcarrier to represent the correlation between the f-th subcarrier and the (f+1)-th subcarrier. The formula for the correlation coefficient is as follows: , , , where X is the first subcarrier containing N samples over a period of time, Y is the second subcarrier containing N samples over the same period of time, and and are sample averages, i is the sample index value, and r is the correlation coefficient between the first subcarrier and the second subcarrier.

20. The electromagnetic wave-based speed estimation method as described in claim 13, wherein the processor performs the speed estimation operation, further comprising: In response to the determination that the identification speed is greater than or equal to a speed threshold, a third signal is generated to indicate that the target is in a high-speed state; In response to the determination that the identification speed is less than the speed threshold, a fourth signal is generated to indicate that the target is in a low-speed state.

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