CN1042084C

CN1042084C - Satellite communications system

Info

Publication number: CN1042084C
Application number: CN 91102808
Authority: CN
Inventors: 罗伯特J·施威特曼
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1991-05-04
Filing date: 1991-05-04
Publication date: 1999-02-10
Anticipated expiration: 2006-05-04
Also published as: CN1066542A

Abstract

The present invention relates to a selective call receiver transmission system used for transmitting messages to a selective call receiver selected from a plurality of selective call receivers, which comprises a transmitter used for transmitting messages including signals. At least one satellite receives the messages and transmits the messages to a selective call receiver and successively forwards the messages to the selective call receiver from different positions.

Description

Increase selective call receiver receives the possibility of information from satellite system method

Present invention relates in general to a kind of selective call receiver receives the possibility of information from satellite system method that increases, utilize this method, increased the selective call receiver receives information from satellite possibility.

Communication that known Satellite Communication System provides point-to-point (point to point).Satellite relay is likely certain zone that this information is forwarded to ground by one or more other satellites from the information of ground transmitter.

But because the Power Limitation in the satellite, this forwarding intensity is very limited.Because some receiver, for example selective call receiver may be in the construction area that forward signal is difficult to penetrate, so not every forward signal can both be obtained.

Therefore, just need one to have the possible Satellite Communication System of increase selective call receiver reception.

Correspondingly, purpose of the present invention just provides a kind of selective call receiver receives the possibility of information from satellite system method that increases.

In order to realize purpose of the present invention, the present invention proposes:

A kind of method that increases the possibility of selective call receiver reception information, this information is launched from satellite system, it is characterized in that this method comprises the steps:

From the transmitter on near-earth ball surface to one first satellites transmits information:

Launch this information from first satellite to receiver from being positioned at a primary importance of calculating with respect to this receiver in the very first time;

This information is transmitted into second satellite; And

Second time after the very first time is launched this information from second satellite of the second place that is different from primary importance calculated with respect to receiver to receiver.

Fig. 1 is the schematic diagram of traditional a plurality of earth-orbiting satellites.

Fig. 2 is the block diagram of inside satellite part.

Fig. 3 be very first time point receive and two earth-orbiting satellites of the scheme of forward signal according to optimum implementation schematic diagram of the present invention.

Fig. 4 be second time point receive and two earth-orbiting satellites of forward signal according to the optimum implementation schematic diagram.

Fig. 5 is the wireless aerial lobe pattern according to two orbiters of optimum implementation.

Referring to Fig. 1, the arrangement of Satellite Communication System comprises several satellites, as 10,11,20 and 21, they are on the Low Earth Orbit of one or more orbit plane A, B, C, D, E and F, and these planes are to tilt highly naturally, and this layout provides comprehensive communication to cover to the earth 12.

In the high dip track structure of optimum implementation, adopt 48 low earth-orbit satellites just can transport to the satisfied earth and cover.These satellites can be disposed on 6 high dip Earth Orbit Planes, 8 satellites in each plane.Also can adopt other to arrange, cover but this layout needs more satellite just can obtain the earth identical with above-mentioned high dip orbital arrangement.

Referring to Fig. 2, each

satellite

10,11,20 and 21 comprise satellite communication circuit 13, suitable antenna 14,15, as be used for the helical antenna of up/downgoing line and be used for the lens that circuit intersects, correspondingly also have one and be connected with storage battery, the solar array 16 of the expansion of power supply is provided for communication system.Solar array promptly launches after satellite is sent into track by delivery vehicle, so communication system activates.These communication systems are by the remote measurement of standard then, track and control channel is included into circuit and forms network.

Satellite Communication System described herein provides frequency spectrum efficiently, and different Satellite Communication Systems can adopt same frequency simultaneously.Each

satellite

10,11,20 and 21 uses and resembles the platform that is transmitted into receiver 18 behind the signal relay that a platform sends transmitter 17.Transmitter receiver can be on the ground of zones of different of the earth, on the delivery vehicle aerial or waterborne.

In the present invention, a plurality of receivers 18, as include the selective call receiver of calling set, it is always relatively fixing to be in any given moment position in the continuous motion at satellite 11.Although the user of receiver 18 can move everywhere, it is relative less that distance is compared with the stroke of satellite on it.Each satellite communication circuit 13 comprises a microprocessor, is used for determining how the signal of launching being relayed to suitable receiver 18 in following mode.

Traditional satellite system can increase the possibility of reception by increasing satellites transmits power, but this method is subjected to the restriction that solar cell can offer the average power of satellite.In addition, in case signal is subjected to the environmental impact of urban area multipath reflection, be the logarithm normal distribution of this distance apart from the variation of the signal level of the given distance of transmitter.The deviation of this distribution (δ) is usually about 8 decibels (db).For the percentage with success is increased to 75 percent from percentage 50, with the excess power gain of needs 0.7 δ or 5.6db.But an incoherent repetition only needs the energy of 3db to increase just can obtain identical result.For the percentage of success is increased to 90 percent power gain that will need 1.1 δ or 8.8db from 90 percent; But one uncorrelated repeats to save the increase of 5.8db energy and reaches same effect.

Referring to Fig. 3 and Fig. 4, according to the present invention, when receiver is in regional that condition of acceptance is restricted, for example between the building 19.At first time point (Fig. 3), information from transmitter 17 be launched into satellite 10 then by relaying (forwarding) to receiver 18.In addition, information also can be looked 17 from emission and directly or from satellite 10 relayings be arrived satellite 11.At second time point (Fig. 4), satellite 11 position different from the previous positions of transmitting of satellite 10 is to receiver 18 forwarding informations.Can be at second time point information by transmitter 17 or satellite 10 or other satellites transmits to satellite 11.The time difference that second for example or a few minutes are arranged between very first time point and second time point.Because receiver can receive the information of emission from different angles, but the acceptance that receiver 18 receives information has increased.In general these different angles have different multipath reflections, thereby produce different signal levels at acceptance point.Which satellite (the received roughly direction of signal) is selected by this system and when (incidence angle) finishes relaying, but so just can farthest increase acceptance.This system realizes these selections by known computerized optimization technology, and is preferably disposed on ground, but also alternately is arranged among one or more satellites.In addition, because receiver 18 can change the position in emitting area between first and second time point, acceptance may further be increased.

Referring to Fig. 5, each satellite can typically throw (project) four or a plurality of lobe (being shown as round zone usually) on earth, and this is to obtain by having with the antenna 14 of the matched fixing beamwidth of lobe number.Although being debated, these are illustrated as four circles, but those skilled in the art should understand, the shape of these lobes and number can be multiple,

satellite

10 and 20 is in the track " D " from the arctic to the South Pole,

satellite

11 and 21 is in from the arctic to South Pole track " E ", although also can utilize other track that comprises retrograde orbit.In order to describe

satellite

10,11,20,21 forwarding informations how illustrate four examples, and wherein alphabetical A, B, C, D representative are at the receiver 18 of very first time point, and alphabetical A+, B+, C+ and D+ representative are at the receiver 18 of second time point.At first, transmitter 17 is to its overhead satellites transmits information, the satellite that this satellite can be any one on the nearer certain tracks of transmitter 17.In example shown in Figure 1, transmitter 17 can be delivered to information satellite 10 and be forwarded to the receiver of putting at " A " again.The user of receiver 18 is in advance with the position of the receiver system as a specific city announcement.At further second time point that moves of south of satellite 11, information is forwarded to receiver 18 at " A+ " point from satellite 11.Information from transmitter 17 can be passed through several satellites before being sent to receiver 18.In a similar fashion, example B has shown that the information from the satellite 11 of same track and 21 transmits, example " C " shown from same satellite 21 send 23 and 24 or 25 in the information of two lobes send, example " D " has shown that the information of the same lobe of sending from same satellite 20 26 transmits.This information can also can be sent to second satellite 11 at any one satellite or the transmitter 17 of second time point among several sources first.

In a word, by at different time points in two different positions (angle) trunk information, but the acceptance of receiver has been increased.

Claims

1. one kind increases the method that selective call receiver receives the possibility of information, and this information is launched from satellite system, it is characterized in that this method comprises the steps:

This information is transmitted into second satellite; And

2. according to the process of claim 1 wherein that step to the second satellites transmits information comprises from the transmitter on the near-earth ball surface step to second this information of satellites transmits.

3. according to the process of claim 1 wherein that described step to the second satellites transmits information comprises step from first satellite to second satellite that transmit this information from.

4. according to the process of claim 1 wherein that described is to carry out with respect to the different position of the position of selective call receiver with second satellite at first satellite since first satellite to the step of the second satellites transmits information.