Irradiance-Based Radiation Source Orientation Method

Abstract

The present invention relates to the technical field of orientation of radiation sources. The present invention discloses a method for orientating a radiation source based on irradiance. The method is characterized by comprising the following steps: accepting irradiation of the radiation source on M side surfaces of a regular pyramid or a regular prismoid and measuring irradiance of the M side surfaces; sequencing the irradiance of the M side surfaces to obtain an orientation sequence; performing Fourier transform on the orientation sequence to obtain a coefficient of each of frequency spectrum component Fourier series; and obtaining an azimuth angle α.sub.s and an elevating angle γ of the radiation source according to a frequency spectrum component of the orientation sequence with an angular frequency of 0 and ±2π/M, wherein M is an integer and is greater than or equal to 3; and in the M side surfaces, unit normal vector azimuth angles of adjacent side surfaces differ from each other at an integer multiple of 2π/M. The orientation method of the present invention may be used for orientation of the sun, orientation of a microwave source and orientation of various radioactive radiation sources.

Claims

1. A method for orientating a radiation source based on irradiance, the method comprising the following steps: accepting irradiation of the radiation source on M side surfaces of a regular pyramid or a regular prismoid and measuring irradiance of the M side surfaces; sequencing the irradiance of the M side surfaces to obtain an orientation sequence; performing Fourier transform on the orientation sequence to obtain a coefficient of each of frequency spectrum component Fourier series; and obtaining an azimuth angle α.sub.s and an elevating angle γ of the radiation source according to a frequency spectrum component of the orientation sequence with the angular frequency of 0 and ±2π/M, wherein M is an integer and M≥3; and in the M side surfaces, unit normal vector azimuth angles of adjacent side surfaces differ from each other at an integer multiple of 2π/M.

2. The method for orientating a radiation source based on irradiance according to claim 1, wherein the radiation source is a light source.

3. The method for orientating a radiation source based on irradiance according to claim 2, wherein the light source is the sun.

4. The method for orientating a radiation source based on irradiance according to claim 2, wherein the radiation source is a voltage or a current output by a photoelectric sensor.

5. The method for orientating a radiation source based on irradiance according to claim 1, wherein the radiation source is a microwave emission source.

6. The method for orientating a radiation source based on irradiance according to claim 5, wherein the radiation source is a voltage or a current output by a Hall sensor.

7. The method for orientating a radiation source based on irradiance according to claim 1, wherein the sequencing the irradiance of the M side surfaces to obtain an orientation sequence specifically comprises: sequencing the irradiance of the M side surfaces to obtain the orientation sequence according to a dimension of an azimuth angle α.sub.i of each of unit normal vectors n.sub.i of the M side surfaces, wherein n.sub.i is the unit normal vector of the ith side surface, α.sub.i is the azimuth angle of n.sub.i, and is equal to 0, 1, to (M−1).

8. The method for orientating a radiation source based on irradiance according to claim 7, wherein the angular frequency is or .

9. The method for orientating a radiation source based on irradiance according to claim 8, wherein an expression formula of the azimuth angle α.sub.s is , wherein α.sub.0 is the azimuth angle of the unit normal vector n.sub.0, and is a frequency spectrum component of the orientation sequence at the angular frequency and ; an expression formula of the elevating angle γ is as follows: $\gamma =\arctan \frac{\text{?}}{\text{?}}\left(.Math.X\left(\text{?}\right).Math./.Math.X\left(\text{?}\right).Math.\right),\text{?}\text{indicates text missing or illegible when filed}$ wherein is the frequency spectrum component of the orientation sequence at the angular frequency of 0.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the disclosure are to provide further understanding of the present invention. The specific implementation modes, schematic embodiments and description thereof are used for explaining the present invention and do not limit the present invention improperly. In the drawings,

[0025] FIG. 1 is a schematic diagram of a geometrical relationship of a vector of a radiation source and a sensor mounting plane on a regular pyramid.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] It is to be noted that in the absence of conflict, the specific implementation modes, the embodiments of the present disclosure and features in the embodiments can be combined with one another. Detailed description on the present invention will be made below in combination with the following contents with reference to drawings.

[0027] In order to make those skilled in the art better understand the scheme of the present disclosure, clear and intact description will be made on technical schemes in the specific implementation mode and the embodiments of the present invention below in combination with drawings in the embodiment of the present invention. The described embodiments are merely a part of embodiments of the present invention and are not all the embodiments. On a basis of the specific implementation modes and embodiments in the present invention, all other implementation modes and embodiments obtained by those skilled in the technical field without creative efforts shall fall into the scope of protection of the present invention.

[0028] Assuming that a ray of the radiation source arriving at an observation point is parallel or a distance from the radiation source to the observation point is far enough, the ray of the radiation source arriving at the observation point may approximately be parallel, for example, sunlight irradiated to the ground. In order to describe a spatial direction of the radiation source and the radiation energy when it arrives at the observation point, we construct a vector directed to the radiation source, a module of which is equal to irradiance (radiation flux in a unit area on a surface of a radiated object) at which the radiation source is incident to the plane vertically. It is defined as a vector of the radiation source. In addition, in order to describe a direction of the vector on a space rectangular coordinate system, we define two angles for the vectors: azimuth angle and elevating angle. The azimuth angle of the vector is the angle from true north (if applied on the Earth), noted here again as the positive y direction, which rotates to the east to a projection of the vector on the x-y plane, and the elevating angle of the vector is an included angle between the vector and the x-y coordinate surface.

[0029] By taking a bottom surface of the regular pyramid as the x-y coordinate plane and a center of a bottom surface thereof as an origin, an x-y-z space rectangular coordinate system is established. It is assumed that side surfaces of the regular pyramid may be irradiated by the radiation source. M sensors (M is greater than or equal to 3) are mounted on these side surfaces to detect the irradiance of the radiation source irradiated to the sensor mounting plane. When the number of the side surfaces of the regular pyramid is smaller than the number of the sensors mounted on the side surfaces of the regular pyramid, a plurality of sensors will detect the irradiance of a same side surface. A geometrical relationship of a vector of a radiation source and a sensor mounting plane is as shown in FIG. 1. In FIG. 1, the sensors are successively numbered from 0 to M−1 in light of amplitudes of the azimuth angles of unit normal vectors of the mounting plane according to an ascending sequence. When two sensors are mounted on a same plane, it is assumed that the azimuth angles of unit normal vectors of their mounting plane are α, and the azimuth angles of the two sensor mounting planes are distributed as α and . When the number of sensors mounted on the same plane is greater than 3, we distribute the azimuth angles of the sensor mounting planes according to the method. The azimuth angle of the vector r of the radiation source is α.sub.s, and the elevating angle is γ; the unit normal vector of the mounting side surface of the sensor , the azimuth angle and the elevating angle of n.sub.i are respectively α.sub.i and β; and the included angle between the vector r of the radiation source and the unit normal vector n.sub.i is φ.sub.i.

[0030] According to cosine law of radiation: the irradiance of any one surface changes along with cosine of the included angle between a radiation energy propagation direction and a normal of the plane, it can be obtained from the geometrical relationship shown in FIG. 1 that the irradiance of the radiation source irradiated to the mounting plane of the sensor P.sub.i is is just equal to an inner product of the vector r of the radiation source and the unit normal vector n.sub.i, that is, . Therefore, the irradiance x.sub.i of the radiation source irradiated to the mounting plane of the sensor P.sub.i is represent as

[00002]$\begin{array}{cc}\text{?}=.Math.r.Math.\cos \phi \text{?}.\text{?}\text{indicates text missing or illegible when filed}& \left(1\right)\end{array}$

[0031] Further, is put into an equation (1) to obtain

[00003]$\begin{array}{cc}\text{?}=n\text{?}r,\text{?}\text{indicates text missing or illegible when filed}& \left(2\right)\end{array}$

[0032] wherein and may be inferred according to the geometrical relationship shown in FIG. 1.

[0033] For light sources such as the sun, the irradiance x.sub.i may be the photoelectric sensor such as a voltage or a current output by a solar battery, a photodiode and the like. For the microwave emission source, the irradiance x.sub.i may be an electromagnetic receiver such as a voltage or a current output by a Hall sensor and the like.

[0034] It is assumed that the azimuth angles of the unit normal vectors of the sensor mounting planes adjacent in number differ . For example, when the number of the side surfaces of the regular pyramid is 3, two sensor planes may be mounted on each side surface. It may be obtained from FIG. 1 that the azimuth angles of the six sensor mounting planes are respectively , and . Similarly, when the number of the side surfaces of the regular pyramid is 6, three sensor planes may be mounted on the side surface of the regular pyramid, such that the azimuth angles of the three sensor mounting planes are respectively and . It may be obtained that the azimuth angle of the unit normal vector n.sub.i of the mounting plane of the sensor P.sub.i may be represented as formula , wherein α.sub.0 is the azimuth angle of the unit normal vector n.sub.0 of the mounting plane of the sensor P.sub.0. Therefore, it may be deduced from the formula (2):

[00004]$\begin{array}{cc}{x}_i=\left(.Math.r.Math.\cos \gamma \cos \text{?}\cos \left(2\pi \text{?}M+{\alpha }_0-{\alpha }_s\right)+.Math.r.Math.\sin \beta \sin \gamma \right),\text{?}\text{indicates text missing or illegible when filed}& \left(3\right)\end{array}$

[0035] wherein and are made, there is

[00005]$\begin{array}{cc}\text{?}=\text{?}\left(2\pi i\text{/}M+{\alpha }_0-{\alpha }_s\right)+\text{?},\text{?}\text{indicates text missing or illegible when filed}& \left(4\right)\end{array}$

[0036] x.sub.i is arranged in sequence according to the number of the azimuth angles of the unit normal vectors of the sensor mounting planes increasingly to form an orientation sequence x(n). From the formula (4), the orientation sequence is obtained:

[00006]$\begin{array}{cc}x\left(n\right)=\text{?}\left(2\pi n\text{/}M+{\alpha }_0-{\alpha }_s\right)+\text{?}0\le n\le M-1,\text{?}\text{indicates text missing or illegible when filed}& \left(5\right)\end{array}$

[0037] wherein Fourier transform or frequency spectrum of the orientation sequence x(n) are set as formula, and it may be obtained from discrete Fourier transformation:

[00007]$\begin{array}{cc}X\left(\text{?}\right)=\underset{n=0}{\overset{M-1}{.Math.}}x\left(\text{?}\right)\text{?},\text{?}\text{indicates text missing or illegible when filed}& \left(6\right)\end{array}$

[0038] as a result of , it may be deduced from the formula (6):

[00008]$\begin{array}{cc}X\left(\text{?}\right)=\frac{\text{?}}{\text{?}}\left(\text{?}G\left(\text{?}\right)+\text{?}G\left(\text{?}\right)\right)+G\left(\text{?}\right),\text{?}\text{indicates text missing or illegible when filed}& \left(7\right)\end{array}$

[0039] wherein,

[00009]$G\text{?}=\text{?}\frac{\text{?}}{\text{?}}$$\text{?}\text{indicates text missing or illegible when filed}$

[0040] and are input in the formula (7), there is

[00010]$\begin{array}{cc}X\left(\text{?}\right)=\frac{\text{?}}{\text{?}}\text{?}=\frac{\text{?}}{\text{?}}M.Math.r.Math.\cos \gamma \cos \beta \text{?},\text{?}\text{indicates text missing or illegible when filed}& \left(9\right)\end{array}$

[0041] wherein X() is a frequency spectrum component of the orientation sequence at an angular frequency 0, and is the frequency spectrum component of the sequence at fundamental angular frequency and . As the fundamental angular frequency of the orientation sequence changes along with the number of the sensors M, the fundamental angular frequency of the orientation sequence changes along with the number of the sensors.

[0042] According to formula (9), formula is the azimuth angle of the vector of the radiation source, i.e., the azimuth angle of the radiation source, which may be obtained from a phase of the orientation sequence at two angular frequency and , and its value is

[00011]$\begin{array}{cc}{\alpha }_s={\alpha }_0\text{?},\text{?}\text{indicates text missing or illegible when filed}& \left(10\right)\end{array}$

[0043] as a result of is made. Therefore, the elevating angle of the vector of the radiation source can be deduced through the formula (8) and formula (9), that is, the elevating angle of the radiation source is:

[00012]$\begin{array}{cc}\gamma =\arctan \frac{\text{?}}{\text{?}}\left(.Math.X\left(\text{?}\right).Math./.Math.X\left(\text{?}\right).Math.\right),\text{?}\text{indicates text missing or illegible when filed}& \left(11\right)\end{array}$

[0044] As the geometric construction of the regular pyramid is known, the azimuth angle α.sub.0 and the elevating angle β of the unit normal vector of the mounting plane of the sensor P.sub.0 are all known. It may be known from the formula (10) and formula (11) that the orientation sequence is formed by irradiance radiated to the side surfaces of the regular pyramid, and the azimuth angle α.sub.s and the elevating angle γ of the radiation source may be solved through the frequency spectrum components of the orientation sequence at the angular frequency 0 and .

[0045] Usually, there is a ratio coefficient between the irradiance of the radiation source irradiated to the sensor mounting plane and its measuring value is not equal to 1, and we define it as a conversion coefficient, for example, a ratio between the output power of a solar battery and energy incident to the surface of the solar battery. Assuming that the conversion coefficient measured by irradiance is a constant η (η>0), the measured value of the irradiance of the radiation source incident to the plane vertically is . It may be known from (8), (9) and (11) that the azimuth angle and the elevating angle of the radiation source are independent of the conversion coefficient. It may be known that the azimuth angle α.sub.s and the elevating angle γ of the radiation source may be solved by measuring the irradiance of the radiation source incident to the sensor mounting plane.

[0046] As a portion, the geometrical relationships between the side surfaces of a regular pyramid the vector of the radiation source are same as that between the side surfaces of its frustum and the vector of the radiation source. It may be known that the azimuth angle α.sub.s and the elevating angle γ of the radiation source may further be solved by adopting the regular prismoid according to the orientation method.

[0047] According to the implementation principle of the orientation method, as long as a discrete sequence formed by irradiance of the radiation source irradiated to the sensor mounting plane is a cosine (or sine) sequence or an overlaying sequence of cosine (or sine) and constant, the radiation source may be oriented by the method.