JPH04297881A - Receiving device for satellite navigation - Google Patents

Abstract

PURPOSE:To know a solar position at some point and the exact time of sunrise and sunset in all weathers and to make them useful for a plan of safe sailing or traveling or the like being made free from a danger, by obtaining information on the latitude, longitude and height of that point from a map or the like. CONSTITUTION:Information on the latitude, longitude and height of the present point is supplied from a satellite navigation receiver l to an arithmetic element 2. From a memory 3, information regarding the solar orbit which set beforehand is supplied to the arithmetic element 2. Based on the aforesaid information, the arithmetic element 2 computes the exact time of sunrise and sunset and displays it in a display element 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for determining the times of sunrise and sunset using data on the latitude, longitude and height of a point on the earth obtained by a satellite navigation receiver.

0002

2. Description of the Related Art Conventionally, the times of sunrise and sunset have been known solely from information released by specialized organizations such as the Japan Meteorological Agency. Satellite navigation receivers (GPS) that use multiple artificial satellites are also known, but they only process information related to navigation.

0003

[Problems to be Solved by the Invention] Due to the above-mentioned situation, it has been impossible to know the exact times of sunrise and sunset at the current location in a short time, for example, when sailing or traveling. Therefore, there were problems in knowing important information for ensuring safety during navigation and travel.

0004

OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems using a known satellite broadcasting receiver.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the satellite navigation receiving device of the present invention calculates the position on the geocentric coordinates of the sun as seen from one point on the earth based on the sun's orbit information. means for calculating the position of the point on geocentric coordinates based on the latitude, longitude and height data at the point given by the satellite navigation receiver; The present invention further comprises means for calculating the angle of elevation and azimuth at which the sun is viewed from the point, and determining the times of sunrise and sunset at the point from the angle of elevation and azimuth.

[0006]

[Operation] Regardless of the weather, it is possible to know the exact sunshine hours at a complex topographical point by taking into account the sun position at the current location, the times of sunrise and sunset, and topographical information.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a satellite navigation receiver according to the present invention. Reference numeral 1 denotes a known satellite navigation receiver, which uses signals from a plurality of satellites to obtain information on the latitude, longitude, and height of the current position on the ground or on the sea. Output. 2 is the calculation unit, 3 is the RAM
, E2P, ROM, and the like, information on the solar orbit, which will be described later, is stored in advance. 4 is the display section, 5 is the CPU, 6
is the operation section.

In response to commands from the operating section 6, the CPU 5 causes the solar orbit information from the memory 3 and the above-mentioned current position information from the satellite navigation receiver 1 to be supplied to the computing section 2, and the computing section 2 receives these information. The following calculations are performed based on:

The procedure for determining the position of the sun by the calculation unit 2 as seen from a point M on the earth will be described below. First, the sun's position on the geocentric coordinates is calculated as follows. The average periapsis elongation Mk at the current time t is determined from the following equation. Mk=Mo+n(t-toe)

...(1) Here, Mo is the average periapsis elongation of the sun at the reference time toe, and n is the average momentum of the sun in the case of elliptical motion. Next, the following Kepl regarding the eccentric periapsis elongation Ek
Solve the er equation. Ek=Mk+e sin(Ek)

...(2) Here, e is the eccentricity of the sun's elliptical motion.

Furthermore, the near point elongation angle Vk is obtained from the following equation. As a result, the latitude declination, radius, and inclination angle of the solar orbit can be determined using the following formulas. Latitude and declination: Uk=Vk+ω

...(4) Radius: rk=A{1-e cos
(Ek)}
...(5) Inclination angle: ik=io+idot(t-
toe)
...(6)

Here, ω is the sun's perigee argument,
A is the semi-major axis of the elliptical orbit, io is the orbital surface inclination angle at toe, and idot is the temporal change in the orbital surface inclination angle. Using these uk and rk, the position Sk on the sun's orbital plane is calculated by the following formula:
(xk', yk') is obtained. xk'=rk cos(uk)

...(7) yk'=rk sin(uk
)
...(8) On the other hand, taking into account the influence of the earth's rotation and the time change Ωt of the solar red diameter, the corrected solar longitude Ωk is determined by the following formula. Ωk=Ωo+(Ωt-ΩE)(t-toe)-
ΩEtoe ...(9) From the above, the sun position S(xs, ys,
zs) is determined by the following formula. xs=xk'cos(Ωk)-yk'cos(
ik) sin(Ωk)…(10)
ys=xk'sin(Ωk)+yk'cos(
ik) cos(Ωk)...(11)
zs=yk'sin(ik)

...(12)

Next, the geocentric coordinates at point M are determined. Equatorial radius R, information from satellite navigation receiver 1
The three components in the geocentric coordinate system of the position of point M at latitude φu, longitude λu, and height h on an elliptical earth with E and eccentricity eE are given by the following equations. xu=(N+h)cos(φu)cos(λu
)...(13)
yu=(N+h)cos(φu)sin(λu)
...(14)
zu={(N(1-eE2)+h)sin(φu)
...(15) Here,

The elevation angle θe at which the sun is viewed from point M is given by the following equation. Here, the azimuth angle θa at which the sun is viewed from point M is given by the following equation.

[0014] Through the above calculation, the position of the sun seen from point M on the earth can be known, and the elevation angle θe is
By finding the time t at which the value is 0 or π, you can know the time when the sun rises and sets. Note that the above calculation is performed using G
This calculation is almost similar to the calculation for searching satellites for positioning in PS receiver 1, and is already used in GPS receiver 1.
It is a built-in calculation processing function, and there is no need to add a new calculation function just by replacing the satellite parameters of this calculation with the target sun. Therefore, the above-mentioned figure 1
GPS can be used without having to provide separate hardware such as the calculation unit
It is also possible to provide the receiver 1 with new software for performing the above-mentioned calculations. Moreover, in the GPS receiver 1, from the purpose of the GPS receiver 1, naturally,
It will have information about the latitude, longitude, and height of the current location. Therefore, it is possible to know the position of the sun at the current position M, and the times at which the sun rises and sets.

FIG. 2 shows the flow of arithmetic processing for determining the times of sunrise and sunset according to the present invention. This calculation process consists of steps S1 to S4 as shown in the figure. 3 and 4 are steps S1 and S2, which are subroutines, respectively.
The flow of the arithmetic processing is shown in detail.

[0016]

As described above, according to the present invention, it is possible to easily know the position of the sun at the current location and the accurate times of sunrise and sunset in any weather. Therefore, you can plan a safe voyage or trip that avoids danger at your current location. In addition, in the present invention, since the sun position at each time is known, by performing calculations that take topographical information into consideration, it is possible to accurately know the sunshine hours even at complex topographical points on land or the like. Further, in the present invention, the data at the point may be obtained from a map or the like other than a GPS receiver.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart of arithmetic processing according to the above embodiment.

FIG. 3 is a flowchart of arithmetic processing in subroutine step S1 of FIG. 2;

FIG. 4 is a flowchart of arithmetic processing in subroutine step S2 of FIG. 2;

[Explanation of symbols]

1 Satellite navigation receiver 2 Arithmetic unit 3 Memory 4 Display section 5 CPU 6 Operation section

Claims (1)

[Claims] [Claim 1] Means for calculating the position of the sun on the geocentric coordinates as seen from a point on the earth based on the sun's orbit information;
means for calculating the position of the point on geocentric coordinates based on latitude, longitude and height data at the point given by a satellite navigation receiver; and means for calculating the position of the point on geocentric coordinates based on the data of the sun position and the data of the point position. 1. A satellite navigation receiver comprising: means for calculating an elevation angle and an azimuth angle at which the sun is viewed from a given angle, and determining the times of sunrise and sunset at the above-mentioned point from the elevation angle and azimuth angle.