Method and apparatus for calibrating installation error in pitch angle of traffic radar, and storage medium

1 . A method for calibrating an installation error in a pitch angle of a traffic radar, comprising:

changing frequency of the traffic radar according to a preset strategy within a preset frequency range;

acquiring energy values of echo signals of a preset target at different frequencies in sequence; and

in response to determining that the acquired energy values of the echo signals satisfy a preset condition, determining frequency corresponding to a maximum energy value of the echo signals as operating frequency of the traffic radar to calibrate the installation error in the pitch angle of the traffic radar;

wherein the preset target is disposed on the ground, and in a horizontal direction of the ground, a distance between the preset target and a projection point of the traffic radar in the horizontal direction is a length of a projection of a central beam of the traffic radar in the horizontal direction when the traffic radar is mounted at an expected pitch angle;

wherein the preset frequency range is determined according to a preset maximum calibration angle and a preset minimum calibration angle of the traffic radar;

wherein determining the preset frequency range according to the preset maximum calibration angle and the preset minimum calibration angle of the traffic radar comprises:

determining a first wavelength when the preset maximum calibration angle is calculated according to a preset equation and determining a first frequency value according to the first wavelength; and

determining a second wavelength when the preset minimum calibration angle is calculated according to the preset equation and determining a second frequency value according to the second wavelength;

wherein the preset frequency range is a range from the first frequency value to the second frequency value, and the preset frequency range comprises the first frequency value and the second frequency value;

the preset equation is as follows:

θ

=

arcsin

⁡

(

λ

λ

g

-

λ

L

f

+

L

P

)

,

wherein θ denotes the preset maximum calibration angle or the preset minimum calibration angle, L f +L p denotes a distance between oscillators of two adjacent radiating units of an antenna of the traffic radar, L f denotes a feed line length between the two adjacent radiating units of the antenna of the traffic radar, L p denotes a patch element length of a radiating unit of the antenna of the traffic radar, λ denotes a wavelength of a millimeter wave of the traffic radar in air, and λ g denotes a wavelength of the millimeter wave of the traffic radar on a dielectric substrate.

2 . The method of claim 1 , wherein the preset strategy comprises changing the frequency from small to large or from large to small by same or different preset step frequencies each time.

3 . The method of claim 1 , wherein the expected pitch angle is determined according to an installation height and a preset detection range of the traffic radar.

4 . The method of claim 1 , wherein

the preset condition comprises the acquired energy values of the echo signals changing from small to large and then from large to small.

5 . The method of claim 1 , wherein the traffic radar is mounted at a preset downtilt angle before the frequency of the traffic radar is changed, the preset downtilt angle not exceeds a designed maximum calibration angle.

6 . The method of claim 5 , wherein the downtilt angle is equal to 5°.

7 . The method of claim 1 , wherein the preset maximum calibration angle is a positive angle value, the preset minimum calibration angle is a negative angle value, and the absolute values of the preset maximum calibration angle and the preset minimum calibration angle are the same.

8 . The method of claim 1 , wherein the preset maximum calibration angle is a positive angle value, the preset minimum calibration angle is a negative angle value, and the absolute values of the preset maximum calibration angle and the preset minimum calibration angle are different.

9 . A non-transitory computer-readable storage medium, which is configured to store a computer program for performing the method for calibrating an installation error in a pitch angle of a traffic radar of claim 1 when the computer program is executed by a processor.

10 . An apparatus for calibrating an installation error in a pitch angle of a traffic radar, comprising:

at least one processor; and

a memory communicatively connected to the at least one processor;

wherein the memory stores instructions executable by the at least one processor to cause the at least one processor to perform a method for calibrating an installation error in a pitch angle of a traffic radar, wherein the method comprises:

changing frequency of the traffic radar according to a preset strategy within a preset frequency range;

acquiring energy values of echo signals of a preset target at different frequencies in sequence; and

in response to determining that the acquired energy values of the echo signals satisfy a preset condition, determining frequency corresponding to a maximum energy value of the echo signals as operating frequency of the traffic radar to calibrate the installation error in the pitch angle of the traffic radar;

wherein the preset target is disposed on the ground, and in a horizontal direction of the ground, a distance between the preset target and a projection point of the traffic radar in the horizontal direction is a length of a projection of a central beam of the traffic radar in the horizontal direction when the traffic radar is mounted at an expected pitch angle;

wherein the preset frequency range is determined according to a preset maximum calibration angle and a preset minimum calibration angle of the traffic radar;

wherein determining the preset frequency range according to the preset maximum calibration angle and the preset minimum calibration angle of the traffic radar comprises:

determining a first wavelength when the preset maximum calibration angle is calculated according to a preset equation and determining a first frequency value according to the first wavelength; and

determining a second wavelength when the preset minimum calibration angle is calculated according to the preset equation and determining a second frequency value according to the second wavelength;

wherein the preset frequency range is a range from the first frequency value to the second frequency value, and the preset frequency range comprises the first frequency value and the second frequency value;

the preset equation is as follows:

θ

=

arcsin

⁡

(

λ

λ

g

-

λ

L

f

+

L

P

)

,

wherein θ denotes the preset maximum calibration angle or the preset minimum calibration angle, L f +L p denotes a distance between oscillators of two adjacent radiating units of an antenna of the traffic radar, L f denotes a feed line length between the two adjacent radiating units of the antenna of the traffic radar, L p denotes a patch element length of a radiating unit of the antenna of the traffic radar, λ denotes a wavelength of a millimeter wave of the traffic radar in air, and λ g denotes a wavelength of the millimeter wave of the traffic radar on a dielectric substrate.

11 . The apparatus of claim 10 , wherein

the preset strategy comprises changing the frequency from small to large or from large to small by same or different preset step frequencies each time.

12 . The apparatus of claim 10 , wherein the expected pitch angle is determined according to an installation height and a preset detection range of the traffic radar.

13 . The apparatus of claim 10 , wherein

the preset condition comprises the acquired energy values of the echo signals changing from small to large and then from large to small.

14 . The apparatus of claim 10 , wherein the traffic radar is mounted at a preset downtilt angle before the frequency of the traffic radar is changed, the preset downtilt angle not exceeds a designed maximum calibration angle.