JPS60153231A - Controlling method of antenna mounted on satellite - Google Patents

Abstract

PURPOSE:To reduce the switching frequency of radio channels and a switchboard by controlling a multi-beam antenna mounted on a periodically circulating satellite for communication so that respective beams are oriented to the same small zones also during the movement of the satellite on a track. CONSTITUTION: The satellite starts its service to a sevice area 7 at a position 6 and the multi-beam antenna mounted on the satellite irradiates small zones 81- 8m respectively precisely. During the period that the satellite moves on the track 5 from the position 6 through positions 6', 6'', the multi-beam antenna irradiates always the same small zones 81-8m. When the satellite passes through the position 6'', the multi-beam antenna is switched to the succeeding service area. Therefore, it is unnecessary to switch the connection of the switchboard in the satellite and to switch radio channels also in an earth station, so that the switching frequency is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a pointing direction control device for a multi-beam antenna mounted on an orbiting communication satellite.

(Prior Art and Problems) FIG. 1 is a conceptual diagram of a communication system using an orbiting communication satellite equipped with a conventional multi-beam antenna. In the figure, 1 is the orbit, 2 and 2' are the satellites, 3°3' are the service areas served by the satellites, 4, ~4x, 4', ~4', and n is the individual satellite multibeam antennas. It represents the small zone irradiated by the beam, and the subscript indicates the beam number, indicating that the total number of beams is integer.

It also indicates that the satellite 2 moves in the direction of the arrow on the orbit 1 and reaches the position of the satellite 2' after a certain time.

In order to avoid the negative effects of radio interference on the radio channels used in the small zones irradiated by the individual beams of the satellite's multi-beam antenna, different radio channels are assigned between adjacent small zones to the extent that radio interference does not become a problem. The same radio channel is assigned between small zones that are sufficiently far apart. In conventional multi-beam antennas, a pointing direction control device 11 is used to correct pointing errors of the multi-beam antenna due to satellite orbit errors, etc., but pointing control device 11 is not performed in conjunction with the orbit of the satellite. As indicated by the arrow in FIG. 1, when the satellite 2 moves on the orbit 1 to the position of the satellite 2', the service area 3 served by the satellite also moves to the position 3'. Therefore, it becomes necessary to switch the small zones 41 to 4m serving each earth station within the service area to small zones 4' and 4'm within a short time.

゛ For example, if orbit 1 is an altitude of 500&x, the diameter of service areas 3 and 3' is 80Az, and +n is 4. In the case of OO, the time for switching the small zones is approximately 10 seconds.

Since the radio channels used differ between adjacent small zones, the earth station needs to switch the radio channel each time the small zone changes.

On the other hand, in the case of a satellite as well, each time the sub-zone serving each earth station changes, the connection of the satellite switch must be changed. In this way, since the small zones serving each earth station are switched in a short period of time, there is a drawback in that both the earth station and the satellite require frequent switching of radio channels or exchanges.

(Object of the Invention) In order to eliminate this drawback, the present invention controls the direction so that each multi-beam always illuminates the same area during the time when the satellite is serving a certain area. This is due to a reduction in the switching frequency of radio channels and intra-satellite exchanges.

(Structure and operation of the invention) FIG. 2 shows an embodiment of the invention. 5 is the orbit, which is the same as in Figure 1. 6.6', 6'' are each time tltt2 and ts(
However, it is assumed that the delay increases in the order of t++ t2y ts. ). 7 is the service area served by satellites 6.6', 6'', and 8I to 8to are the small zones serviced by the individual beams of the multi-beam antenna. Zones 4+-4+a, 4', and -4'm have the same area, but they do not move with the movement of the satellite and are fixed on the ground.In 9 and 10, the ground-L trajectory of orbit 5 is the same as that of service area 7. The intersection α9 is directly below the satellite 6, and the intersection 10 is directly below the satellite 6''. The satellite starts service to service area 7 at the position of satellite 6, and the multi-beam antenna starts serving small zones 81-8.
Irradiate each lees accurately. The satellite moves from satellite 6 to satellite 6' to satellite 6'', but during this time the multi-beam antenna always illuminates the same small zone 81 to 8 m.When the satellite passes the 16th position of satellite 6'', the next Switch the multi-beam antenna to the service area. therefore,
Time 1. -1. In-satellite switching does not require connection switching.

In the previous example, in the system where orbit 5 has an altitude of 500 kHz and service area 3 has a diameter of 80 Ax, time t1~ is about 3.
It is 5 minutes. There is no need for the earth station to switch radio channels during this time either.

Furthermore, multiple satellites are arranged in orbit 5 so that when a satellite is at the position of satellite 6'', the following satellite is at the position of satellite 6'', and each satellite's multi-beam antenna pattern and each sub-zone are If the radio channels used by the earth stations are made the same, the earth station can communicate with the satellites one after another without disconnection and without switching the radio channels used.

Incidentally, the satellite multi-beam antenna pointing control can be easily performed using a well-known technique such as a seven-aided array antenna technique or a technique of mechanically controlling the attitude of an antenna reflector and a power feeding section.

(Effect of the invention) As explained above, since the small zone illuminated by the multi-beam antenna of the orbiting communication satellite illuminates a fixed area and does not move with the movement of the satellite, switching between the in-satellite switching equipment and the earth station is possible. It has the advantage of significantly reducing the frequency.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a communication system using an orbiting communication satellite equipped with a conventional multi-beam antenna, and FIG. 2 is an embodiment of the present invention. 1...orbit, 2.2'...satellite, 3,
3'...Service area, 41~4m, 4'
, ~4'm...Small zone, 5...Orbit, 6.6', 6"...Satellite, 7...Service area, 81~ 8w...Small zone, 9゜1
0...The intersection point where the ground trajectory of orbit 5 intersects with the boundary of service area 7 Agent Patent attorney Takashi Honma

Claims (1)

[Claims] In a communication system using an orbiting communication satellite equipped with a multi-beam antenna, when the satellite is positioned at a predetermined service start position for a certain service area, all beams of the satellite's antenna are transmitted to the area within the service area. Each beam is directed to each predetermined small zone, and while the satellite moves in orbit, each beam is controlled to be directed to the same small zone, and when the satellite reaches the predetermined service end position, the satellite beam A satellite-mounted antenna control system characterized by directing all beams of the antenna to a next service area.