WO2007084165A2

WO2007084165A2 - Satellite scanning maritime beam for two-way broadband services

Info

Publication number: WO2007084165A2
Application number: PCT/US2006/013245
Authority: WO
Inventors: Roger R. Taur; Xiaoguang Jia Taur; Ted Mitsuteru Sugiki; Kiroyuki Okamoto
Original assignee: ASTRO RESEARCH Corp; Astro Research Corp
Current assignee: ASTRO RESEARCH Corp; Astro Research Corp
Priority date: 2005-04-22
Filing date: 2006-04-10
Publication date: 2007-07-26
Anticipated expiration: 2007-10-22
Also published as: WO2007084165A3

Abstract

A method of providing a cost-effective two-way maritime broadband service to at least one ship located in a predetermined shipping channel. The method comprises the following steps: (A) providing at least one broadband satellite system (BSS) 50; (B) scanning at least one predetermined shipping channel by at least one spot beam generated by at least one broadband satellite system (BSS); and (C) providing a broadband scheduled service for each ship located in the shipping channel.

Description

SATELLITE SCANNING MARITIME BEAM FOR TWO-WAY BROADBAND SERVICES

FIELD OF THE INVENTION

The present invention is in the field of space applications. More specifically, the present invention relates to utilization of satellite scanning maritime beams for two-way broadband services.

BACKGROUND ART

The currently available commercial maritime satellite service is limited to narrow band and voice. For land based satellite system, low cost broadband services will become available very soon, such as the WildBlue system. WildBlue covers the entire contiguous U.S. or CONUS with multiple spot beams. Because the ocean areas are vast, to cover the entire ocean with spot beam for the economical broadband service is not cost effective. WildBlue covers the CONUS with 35 beams and it will take more than 300 spot beams to cover the Pacific Ocean. It will take eight dedicated big satellites to provide the service.

SUMMARY OF THE INVENTION

To address the shortcomings of the available art, the present invention provides for employing satellite scanning maritime beams for two-way broadband ser- vices.

One aspect of the present invention is directed to a method of providing a cost-effective two-way maritime broadband service to at least one ship located in a predetermined shipping channel . In one embodiment of the present invention, the method comprises the following steps: (A) providing at least one broadband satellite system (BSS) ; (B) scanning at least one predetermined shipping channel by at least one spot beam generated by at least one broadband satellite system (BSS) ; and (C) providing a broadband scheduled service for each ship located in the shipping channel . In this embodiment of the present invention, the BSS generates at least one spot beam. In this embodiment of the present invention, the BSS satellite is configured to provide a broadband service .

In one embodiment of the present invention, the step (A) of providing at least one broadband satellite system (BSS) further comprises the step (Al) of providing a broadband satellite system (BSS) that generates a single spot beam covering at least one predetermined shipping channel . In another embodiment of the present invention, the step (A) of providing at least one broadband satellite system (BSS) further comprises the step (A2) of providing a broadband satellite system (BSS) that generates a plurality of independent scanning spot beams covering at least one predetermined shipping channel . In one more embodiment of the present invention, the step (A) of providing at least one broadband satellite system (BSS) further comprises the step (A3) of providing a multibeam network of BSS, wherein each BSS generates a single spot beam, and wherein the multibeam network of BSS generates a plurality of spot beams covering at least one predetermined shipping channel . In this embodiment of the present invention, the plurality of spot beams is used to provide a broadband service with broadened schedule .

In one embodiment of the present invention, the step (B) of scanning at least one predetermined shipping channel by at least one spot beam generated by at least 2

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one broadband satellite system (BSS) further comprises the following steps: (Bl) determining a service zone contour within at least one predetermined shipping channel; (B2) determining a geometrical contour including the service zone within at least one predetermined shipping channel as seen from at least one BSS satellite; and (B3) steering a BSS transmitting and receiving means to scan an area within the geometrical contour including the service zone within at least one predetermined shipping channel by at least one spot beam of the BSS.

In one embodiment of the present invention, a service zone contour within at least one predetermined shipping channel is determined in a satellite- centered coordinate system. In one embodiment of the present invention, the step (B) of scanning at least one predetermined shipping channel by at least one spot beam generated by at least one broadband satellite system (BSS) further comprises the step (B4) of scanning at least one predetermined shipping channel by at least one spot beam generated by at least one broadband satellite system (BSS) for a predetermined time duration.

In one embodiment of the present invention, the step (B) of scanning at least one predetermined shipping channel by at least one spot beam generated by at least one broadband satellite system (BSS) further comprises the step (B5) of scanning at least one predetermined shipping channel by at least one spot beam generated by at least one broadband satellite system (BSS) at a prede- termined scanning rate.

In one embodiment of the present invention, wherein the transmitting and receiving means comprises a BSS antenna, the step (B3) of steering the BSS transmitting and receiving means to scan the area within the geometrical contour including the service zone within at least one predetermined shipping channel further comprises the step (B3, 1) of mechanically steering the BSS antenna by using a mechanical means located on board of the BSS. In one embodiment of the present invention, wherein the transmitting and receiving means comprises a phase- array BSS antenna, the step (B3) of steering the BSS transmitting and receiving means to scan the area within the geometrical contour including the service zone within at least one predetermined shipping channel further comprises the step (B3, 2) of electronically steering the phase-array BSS antenna by using an electronic means located on board of the BSS.

In one embodiment of the present invention, the step (C) of providing the broadband scheduled service for each ship located in at least one shipping channel further comprises the step (Cl) of providing the broadband scheduled service in Ka band.

Another aspect of the present invention is directed to a method of utilizing a broadband scheduled service provided by at least one broadband satellite system (BSS) to at least one ship located within at least one predetermined shipping channel, wherein each such ship is equipped with a ship satellite tracking station (SSTS) comprising a tracking satellite antenna.

In one embodiment of the present invention, the method comprises the following steps: (A) performing tracking of at least one spot beam generated by the BSS by using the satellite antenna of at least one ship sat- ellite tracking station (SSTS) ; and (B) gaining access to the broadband scheduled service provided by at least one broadband satellite system (BSS) by using at least one spot beam being tracked.

In one embodiment of the present invention, the step (B) of gaining access to the broadband βcheduled service provided by at least one broadband satellite system (BSS) by using at least one spot beam being tracked further comprises the following steps: (Bl) gaining access to a spot beam having a bandwidth (BW) by using a forward data link having frequency f_{forward link} at a first data rate First_bits_ per_second and using a return data link having frequency f_{return liπk} at a second data rate Second_bits_ per_second; wherein the spot beam provides access to N communication channels; and (B2) downloading a set of data during a time period T.

In one embodiment of the present invention, the step (B2) of downloading the set of data during the time period T further comprises the step (B2 , 1) of downloading a set of data selected from the group consisting of: {detailed weather maps; news and sports programs; and movies} .

One more aspect of the present invention is directed to a method of exchanging data between at least two ships located within at least one shipping channel by utilizing a broadband scheduled service provided by at least one broadband satellite system (BSS) , wherein each such ship is equipped with a ship satellite tracking station (SSTS) comprising a tracking satellite antenna.

In one embodiment of the present invention, the method comprises the following steps: (A) using a satellite antenna of the first ship satellite tracking station (SSTS) to perform tracking of at least one spot beam generated by the BSS; (B) gaining access to at least one broadband satellite system (BSS) by the first ship; (C) using a satellite antenna of the second ship satellite tracking station (SSTS) to perform tracking of at least one spot beam generated by the BSS; (D) gaining access to at least one broadband satellite system (BSS) by the - S -

second ship; and (E) using at least one broadband satellite system (BSS) to exchange data between the first ship and the second ship.

Yet one more aspect of the present invention is directed a system for providing a cost-effective two-way maritime broadband service to at least one ship located in a predetermined shipping channel .

In one embodiment of the present invention, the system comprises: (A) a broadband satellite system (BSS) means for generating at least one spot beam; (B) a means for scanning at least one predetermined shipping channel by at least one spot beam; and (C) a means for providing a broadband scheduled service for each ship located in the shipping channel . In one embodiment of the present invention, the means (A) of the broadband satellite system (BSS) further comprises at least one broadband satellite system (BSS) generating a single spot beam covering at least one predetermined shipping channel . In another embodiment of the present invention, the means (A) of the broadband satellite system (BSS) further comprises at least one broadband satellite system (BSS) generating a plurality of independent scanning spot beams covering at least one predetermined shipping chan- nel.

In one more embodiment of the present invention, the means (A) of the broadband satellite system (BSS) further comprises a multibeam network of BSS, wherein each BSS generates a single spot beam, and wherein the multibeam network of BSS generates a plurality of spot beams covering at least one predetermined shipping channel. In this embodiment of the present invention, the plurality of spot beams is used to provide a broadband service with broadened schedule. In one embodiment of the present invention, the means (B) for scanning at least one predetermined shipping channel further comprises: (Bl) a means for determining a service zone contour within at least one prede- termined shipping channel in a satellite-centered coordinate system; (B2) a means for determining a geometrical contour including the service zone within at least one predetermined shipping channel as seen from at least one BSS satellite; and (B3) a means for steering a BSS trans- mitting and receiving means to scan an area within the geometrical contour including the service zone within at least one predetermined shipping channel by using at least one spot beam of the BSS.

In one embodiment of the present invention, wherein the transmitting and receiving means comprises a BSS antenna; the means (B3) for steering the BSS transmitting and receiving means to scan the area within the geometrical contour including the service zone within at least one predetermined shipping channel further com- prises a mechanical means for steering the BSS antenna.

In one embodiment of the present invention, wherein the transmitting and receiving means comprises a phase- array BSS antenna, the means (B3) for steering the BSS transmitting and receiving means to scan the area within the geometrical contour including the service zone within at least one predetermined shipping channel further comprises an electronic means for steering the phase-array BSS antenna.

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned advantages of the present invention as well as additional advantages thereof will be more clearly understood hereinafter as a result of a detailed description of a preferred embodiment of the invention when taken in conjunction with the following drawings .

FIG. 1 shows a case design of scanning beam maritime two-way satellite broadband service of the pres- ent invention including a plurality of a Ka-band scanning spot beams covering several predetermined shipping channels from LA to Hawaii, and from Alaska to LA and Panama Channel .

FIG. 2 illustrates the overview of the broad- band satellite system (BSS) capable of generating at least one spot beam for the purposes of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents that may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be obvious to one of ordinary skill in the art that the present invention may be practiced with- out these specific details. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the present invention. Historically, satellites have been most successful in distributing information over very large geographical areas using a single transmission. With services such as television broadcasting, data broadcasting, digital messaging, enterprise virtual private networks

(VPNs) and point-to-point telecom-datacom services, traditional "bent-pipe" satellites have played a significant role in our daily lives. A new generation of application needs, higher throughput requirements, and communication demands are changing the way satellite systems are designed, implemented and operated. New architectures and system networking concepts are being implemented to make satellite systems capable of addressing these new market demands. The progressive idea of making satellite sys- terns that are optimized for highly in demand services (e.g., Internet access, VPNs, personal access) opens entire new market opportunities that go far beyond the traditional viewpoint of selling services only into markets that where satellite services excel (e.g., broad- casting, multicasting and content delivery) .

Broadband satellite systems both receive and transmit rich-media content to and among network end- users whether at home or in the office-these systems are not intended to supply huge amounts of bandwidth for backbone infrastructure purposes. The market need is great for two-way broadband network access across large geographical areas where infrastructure has not been built out, or would be too costly to implement. In short, satellite will become the broadband "local-loop" in such communities.

There are four basic technology categories that form the basis for the various satellite broadband service offerings: Ku-band FSS, bent pipe Ka-band, on-board processing Ka-band and L-band MSS. The first generation services that are now in place use existing Ku-band fixed satellite service (FSS) satellites for two-way connections. Using FSS, a large geographical area (e.g., the United States or all of North America) is covered by a single broadcast beam. The new Ka-band systems use more focused beams that cover a much smaller area (hundreds of miles across, rather than thousands of miles with FSS) that form coverage cells like the illustration below. Adjacent cells use different frequency ranges but a given frequency range can be reused many times over a wide geographical area. In this way there is a large increase in overall capacity because of frequency reuse; the spot beam frequency gain is analogous to the difference between a direct-to-home broadcast signal and cellular phone cover- age. From a practical standpoint, Ka spot beams provide 30 to 60 times the system capacity of the FSS approach. The increase system capacity to 30 Gbps plays a very significant role in helping to make satellite broadband services a long-term, economically viable business oppor- tunity, as end-users' bandwidth requirements will only increase over the next five to ten years.

The Ka-band systems under development are being designed with two basic constructs : bent pipe and onboard processing. Bent-pipe satellites are essentially repeaters in the sky-they simply receive and retransmit signals without performing any additional functions like multiplexing, switching or routing. All waveform processing intelligence, like rain fade mitigation or data rate adjustment, is performed by the ground station ter- minal equipment. This bent-pipe approach is much less complex, less costly, and is less susceptible to obsolescence than the on-board processing approach.

On-board processing payloads act as intelligent signal routers and switches, directing traffic from one spot beam to another within the same satellite or to another sibling satellite to provide large regional or global single- hop connectivity. On-board processing enables very efficient full-mesh broadband connections that can adapt quickly to changing data throughput and system loading demands-all key attributes for enterprise networking and the increasing importance of supporting peer-to-peer networking applications.

Broadband means bandwidth, and in any media more bandwidth means higher transmission costs. Until now satellites have been delivering content (TV, movies or real-time data) to large numbers of content consumers using a single transmission. The economic gain for this point-to-multipoint distribution in terms of cost per user/receiver is phenomenal and easily surpasses any other media-fiber, cable/coax, copper or wireless local loop. However, for two-way interactive connections, satellites require a return channel from the user location, which significantly impacts the economic equation. Internet access and networking services will have an increasing dependence on high-bandwidth capacity. This demand for continual performance increase requires that service providers plan accordingly and carefully evaluate their overall implementation approach so that their businesses have longer term viability. The commercial success of a satellite broadband service offerings will be closely linked with three key factors: (1) deploying a system with sufficient subscriber capability, service capacity, and scalability; (2) maximizing the return on investment (ROI) of space segment (e.g., high utilization subscriber/Mbps) ; and (3) supporting essential business functions and practices in an efficient manner.

All of the above factors are significantly influenced by the overall system design and implementa- tion. The first is closely inter-related. System through- put and user demand vary significantly as a function of time of day and the types of applications used by the end-users. The application type affects the amount of data to be transferred, the timeliness of information and the number of concurrent applications to be supported across the network, or a geographical area (e.g., within a particular spot beam) .

Globally there is a strong need for new two-way broadband systems to reliably deliver IP-based services to large numbers of residential subscribers and enterprise users . Current infrastructures do not provide the necessary capacity, reach capability and service price points to satisfy this growing demand in all geographical areas-and satellite based systems are being deployed to provide the needed broadband "local-loop" service. Because of the diverse market requirements-service and network terminal costs, types of services, throughput performance and service quality levels-no single broadband system can address multiple market segments. FIG. 1 shows a case design of scanning beam maritime two-way satellite broadband service of the present invention including a plurality of a Ka-band scanning spot beams covering several predetermined shipping channels from LA 11 to Hawaii 21 (spot beams 12, 14, 16, 18, and 20), from Alaska 31 to LA 11 (spot beams 24, 26, 28, 30) and from LA 11 to Panama Channel 37 (spot beams 32, 34, 36) . The typical Ka frequency band includes 30 GHz.

In one embodiment of the present invention, the beam size used in the present invention is 1.6°, twice of that of the prior art WildBlue beam, and covers an area of about 1,000 km in diameter. Coverage area is a geographical area, which moves in time with the satellite, which defines the antenna coverage of a particular satellite. The prior art WildBlue approach is based on two-way wireless Ka-band spot beam satellite technology. WildBlue uses Ka-band "spot beam" satellites to allow multiple re-use of the same frequency, providing higher capacity at lower cost compared to other available satellite systems. WildBlue core service offers homes and small offices/home offices (SOHO) an Internet connection that is easy to use, reliable, always on, and more than 30 times faster than standard dial-up service. WildBlue Internet service for consumers includes typical Internet Service Provider features (email, web space, etc.) . With WildBlue, for example, consumers can download a movie on demand, attend University courses hundreds of miles away or quickly email a family photo. Though these services are familiar to some, 20-25 million homes and small offices across the country can access high-speed internet services exclusively because of the WildBlue technology. Most computers in use today will meet WildBlue minimum system requirements. For PC/ Windows, the WildBlue mini- mum system requirements are: 300 MHz or faster processing speed, minimum 128 MB Random Access Memory (RAM) , and Windows 98SE, ME, 2000, or XP operating system, 100 MB of hard drive space and an ethernet card. For Macintosh, the WildBlue minimum system requirements are: 300 MHz or faster processing speed, 128MB Random Access Memory

(RAM), and OS 9, OS 10.2 or higher operating system, 100 MB of hard drive space and an ethernet card.

In one embodiment, the broadband satellite system (BBS) of the present invention further comprises a satellite means (not shown) for generating at least one spot beam to cover at least one predetermined shipping channel (of FIG. 1) . In another embodiment of the present invention, the broadband satellite system (BSS) further comprises at least one broadband satellite system (BSS) generating a plurality of independent scanning spot beams covering at least one predetermined shipping channel (not shown) . In one more embodiment of the present invention, the broadband satellite system (BSS) further comprises a multibeam network of BSS, wherein each BSS generates a single spot beam, and wherein the multibeam network of BSS generates a plurality of spot beams covering at least one predetermined shipping channel . In this embodiment of the present invention, the plurality of spot beams is used to provide a broadband service with broadened schedule.

FIG. 2 illustrates the overview of the broadband satellite system (BSS) 50 capable of generating at least one spot beam for the purposes of the present invention. In one embodiment of the present invention, more specifically, the Yamal-200 spacecraft is useful in operation at 139° West Longitude (WL) at a geostationary orbit slot to provide coverage of several predetermined shipping channels, for example, from LA 11 to Hawaii 21 (spot beams 12, 14, 16, 18, and 20), from Alaska 31 to LA 11 (spot beams 24, 26, 28, 30), and from LA 11 to Panama Channel 37 (spot beams 32, 34, 36), as shown in FIG. 1.

The Yamal-200 spacecrafts are built by Rocket- Space Corporation Energia named after S. P. Koroliov and JSC Gascom in cooperation with Space Systems/Loral and

NEC. In the design of these satellites, RSC Energia used its fully developed Multi-purpose Unpressurized Satellite Bus that includes the modular principle. The Yamal-200 satellites are designed to operate in orbit for more than 12 years. For the purposes of the present invention, the Yamal-200 spacecraft should have more than 15 years of mission life.

Yamal-200 satellites are designed for transmission of large amounts of data. The mass of Yamal-200 satellites is about 1360 kg. They can be launched by using the Proton-Yamal integrated launch vehicle consisting of Proton-K launch vehicle (LV) , the space upper stage of the Block DM-type as the fourth stage and a satellite stack of two spacecraft Yamal-200. The Yamal-200 spacecraft can be equipped with a combined C and Ka band payload and is designed to provide advanced communications links including voice and fax communications, videoconferencing, transmission of digital data and TV programs, connection to the Internet. Herein, C-band is a band of frequencies in the 4 to 8 GHz frequency transmission range that are used for satellite and terrestrial communications; wherein Ka-Band is a band of frequencies in the 18 to 31 GHz range that are available for global satellite use. Yamal Satellite Communication and Broadcast

System consists of ground and space segments. The ground segment should include: satellite communication and broadcast networks including a plurality of earth stations, a plurality of teleports, a multichannel digital satellite TV broadcast system that includes satellite digital TV broadcast center and a digital television network, and a fiber-optic line connecting teleports. The space segment should include a Yamal-200 satellite, and a Ground control complex for Yamal series satellites. For the purposes of the present invention, the

Yamal-200 satellite should use 12:8 130 W linearized Traveling Wave Tube Amplifiers (TWTAs) as a source of power for communication with the users, and should utilize 4:2 98 W TWTAs as a source of power for communica- tion with the Gateway (GW) .

The output amplifier provides the power at the output of each channel and this determines the value of effective isotropic radiated power (EIRP) of the channel . The reference amplifier output power is defined by the single carrier saturation power. The TWTA amplifier operates by interaction between an electron beam and the radio wave. The electron beam, generated by a cathode raised to a high temperature, is focused and accelerated by a pair of anodes. The wave propagates along a helix; the electron beam, whose focus is maintained by concentrically located magnets, flows within the helix. The axial velocity of the wave is artificially reduced by the helix to a value close to the velocity of the electrons . The interaction leads to a slowing of the electrons which give up their kinetic energy. A collector captures the electrons at the output of the helix. Division of the collector into several stages at different potential permits better matching to the dispersion of the residual energy of the electrons and hence an increase in the efficiency of the tube. Typical values of the characteristics of the tubes are as follows: (a) power at saturation is from 20-200W; (b) efficiency at saturation is 55-70%; (c) gain at saturation is around 55dB; (d) AM/PM conversion coefficient K_p is around 4.5° /dB (near saturation) .

For the purposes of the present invention, the Yamal-200 satellite should operate at C/Ka-band and should utilize a TC&R transponder. Transponder is a component of a communications satellite that receives a signal from earth, processes and amplifies it, and then re-transmits it to another location on earth.

The TC&R transponder should include several main features that are compatible with ESA and NASA TCR standards. TC&R transponder should include both coherent and non-coherent operating modes available by telecommand, and should be compatible with most bus interfaces (primary bus, command & telemetry formats) . The TC&R transponder should include a Telecommand & Ranging Receiver having a number of modulation options PCM/PSK/PM and using NRZ-L or TC subcarrier (custom-tailored) at its output . The TC&R transponder should also include a Telemetry & Ranging Transmitter having different types of modulation PCM/PSK/PM and using simultaneous TM+RG subcarriers modulation, including TM direct modulation using SPL coded NRZ signals. TC&R transponder can use BPSK/QPSK transmitters that are available on demand. TC&R transponder can also use additional High Power Amplifier (HPA) that are available as a separate module.

For the purposes of the present invention, the Yamal-200 satellite should include eight 0.8° user beams that is sufficient to cover the service area as shown in FIG. 1. For the purposes of the present invention, the Yamal-200 satellite should include one gateway beam (LA) . For the purposes of the present invention, the Yamal-200 satellite should include equal forward and return bandwidth to each user.

For the purposes of the present invention, the Yamal-200 satellite should include two 4:2 down converter rings. The downconverter and power supply unit should be built into a machined 0-ring. For instance, the L band

RHCP feed/downconverter used for NOAA polar orbiting satellite reception, manufactured by Quorum Communications, Inc., located at 8304 Esters Blvd, Suite 850, Irving, TX 75063, could be used for the purposes of the present invention.

QThe downconverter receives the amplified broadband satellite signal from the LNA and converts it into a lower frequency (lower frequencies) which can be used efficiently by the receiver. The downconverter in older satellite systems actually rejects the signals from all of the transponders except one and converts this one- transponder signal into an intermediate frequency (IF) for use by the remainder of the receiver circuits. It might be compared to the mixer and IF stages of a TV receiver or radio. The block downconverter in later satellite receivers converts the broadband signal received from the LNA into a block of frequencies which can be used by a receiver. The receiver receives the whole block of fre- guencies and tunes in the desired transponder's signal while tuning out the remaining signal . This arrangement makes it possible for multiple receivers to be served by the same dish, each receiver selecting the desired transponder . For the purposes of the present invention, the

Yamal-200 satellite should not have RF autotrack. Indeed, the tracking is not necessary when the antenna beamwidth is large in comparison with the station-keeping box of a geostationary satellite or for the case of a system of satellites includes elliptical orbits when the antenna beamwidth greatly exceeds the solid angle which contains the appropriate movement of the active orbiting satellite .

In one embodiment, the BBS system of the pres- ent invention further comprises a means for scanning (not shown) at least one predetermined shipping channel (of FIG. 1) by at least one spot beam. In one embodiment of the present invention, the means for scanning at least one predetermined shipping channel by at least one spot beam further comprises: a means for determining a service zone contour within at least one predetermined shipping channel in a satellite-centered coordinate system; a means for determining a geometrical contour including the service zone within at least one predetermined shipping channel as seen from at least one BSS satellite; and a means for steering a BSS transmitting and receiving means to scan an area within the geometrical contour including the service zone within at least one predetermined shipping channel by using at least one spot beam of the BSS. In one embodiment of the present invention, the service zone reference points are identified in a satellite-centered coordinate system. The co-ordinate system (not shown) contains an axis oriented in satellite-earth center direction (the z-axis) , an axis perpendicular to the first in a plane parallel to the equatorial plane and oriented towards the east (the y axis) , and an axis normal to the other two (the x axis is oriented towards the north for a satellite in the equato- rial plane) . A point P on the surface of the earth has coordinates x_p/ y_p, z_p in the satellite coordinate system. These coordinates are calculated as a function of the altitude of the satellite and the coordinates of the sub- satellite point. In the case of the geostationary satellite, the relations can be obtained from the relative longitude L of the satellite and the point concerned and the latitude 1 of this point.

Representation of the service zone contour on a map poses the problem of converting from three-dimensional space to a plane. One representation consists of using a reference plane tangential to the surface of the earth at the sub-satellite point and performing a projection of the points on the surface of the earth on to this plane.

The service zone has a zone of uncertainly resulting from the antenna pointing error. The geometrical contour of the service zone includes the combined effects of de-pointing of the antenna due to the satel- lite motion and deformation of the service zone contour due to the relative displacement of the satellite with respect to the geographical region.

In one embodiment of the present invention, the steering means configured to scan the area within the geometrical contour including the service zone within at least one predetermined shipping channel further comprises a mechanical means for steering the BSS antenna. In this embodiment, a servomotor can enable the mechanical steering of the satellite antenna. In another embodiment of the present invention, the steering means configured to scan the area within the geometrical contour including the service zone within at least one predetermined shipping channel further comprises an electronic means for steering the BSS antenna. In this embodiment of the present invention, the transmitting and receiving means comprises a phase- array BSS antenna .

Phased array antennas with many independently steerable beams require a large number of radiating ele- ments with individual phase (and amplitude) control for each beam. This signal control can be implemented with analog circuits (for a small number of beams) or digitally. The digital implementation requires substantial digital processing. Phased array antennas are used on the Iridium and Globalstar satellites. Thus, the satellite antenna spot beams can be scanned mechanically or electronically and both technologies are mature and flight proven.

In one embodiment of the present invention, the BBS system of the present invention further comprises a means for providing a broadband scheduled service for each ship located in the shipping channel .

In one embodiment of the present invention, bandwidth for each spot beam is 150 MHz and 120 channels can be provided for the 1.544 Mbps and 512 Kbps forward and return data links for each user. If each user requires 400 GB download for each visit, it will take about 35 minutes. Therefore, for example, for the LA-Hawaii shipping channel, each scan will take about 2.5 hours. If each user takes up ten channels, then each complete scan takes less than 30 minutes. The system is very flexible. For the Alaska-Panama shipping channels, the scanning rate is doubled.

The user's equipment (or the ship tracking station) includes the satellite tracking antenna, outdoor unit (ODU), indoor unit (IDU), and personal computer. The satellite tracking antenna is about 0.5 m in diameter and tracking accuracy requirement is about 0.2°, well within capability of the current commercial market an- tenna. The ODU and IDU are identical to that of the Ka- band system.

One aspect of the present invention is directed a method of providing a cost-effective two-way maritime broadband service to at least one ship located in a pre- determined shipping channel .

In one embodiment of the present invention, the method comprising the following steps (not shown) : (A) providing at least one broadband satellite system (BSS) ; (B) scanning at least one predetermined shipping channel by at least one spot beam generated by at least one broadband satellite system (BSS) ; and (C) providing a broadband scheduled service for each ship located in the shipping channel . In this embodiment of the present invention, the BSS generates at least one spot beam. In this embodiment of the present invention, the BSS satellite is configured to provide a broadband service.

In one embodiment of the present invention, the step (A) of providing at least one broadband satellite system (BSS) further comprises the step (Al) of providing a broadband satellite system (BSS) that generates a single spot beam covering at least one predetermined shipping channel . In another embodiment of the present invention, the step (A) of providing at least one broadband satellite system (BSS) further comprises the step (A2) of providing a broadband satellite system (BSS) that gener- ates a plurality of independent scanning spot beams covering at least one predetermined shipping channel . In one more embodiment of the present invention, the step (A) of providing at least one broadband satellite system (BSS) further comprises the step (A3) of providing a multibeam network of BSS, wherein each BSS generates a single spot beam, and wherein the multibeam network of BSS generates a plurality of spot beams covering at least one predetermined shipping channel . In this embodiment of the present invention, the plurality of spot beams is used to provide a broadband service with broadened schedule .

In one embodiment of the present invention, the step (B) of scanning at least one predetermined shipping channel by at least one spot beam generated by at least one broadband satellite system (BSS) further comprises the steps of: (Bl) determining a service zone contour within at least one predetermined shipping channel; (B2) determining a geometrical contour including the service zone within at least one predetermined shipping channel as seen from at least one BSS satellite; and (B3) steering a BSS transmitting and receiving means to scan an area within the geometrical contour including the service zone within at least one predetermined shipping channel by at least one spot beam of the BSS.

In one embodiment of the present invention, a service zone contour within at least one predetermined shipping channel is determined in a satellite- centered coordinate system. In one embodiment of the present invention, the step (B) of scanning at least one predetermined shipping channel by at least one spot beam generated by at least one broadband satellite system (BSS) further comprises the step (B4) of scanning at least one predetermined shipping channel by at least one spot beam generated by 2

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at least one broadband satellite system (BSS) for a predetermined time duration.

In one embodiment of the present invention, wherein the transmitting and receiving means comprises a BSS antenna; the step (B3) of steering the BSS transmitting and receiving means to scan the area within the geometrical contour including the service zone within at least one predetermined shipping channel further comprises the step (B3 , 1) of mechanically steering the BSS antenna by using a mechanical means located on board of the BSS. In one embodiment of the present invention, wherein the transmitting and receiving means comprises a phase- array BSS antenna, the step (B3) of steering the BSS transmitting and receiving means to scan the area within the geometrical contour including the service zone within at least one predetermined shipping channel further comprises the step (B3, 2) of electronically steering the phase-array BSS antenna by using an electronic means located on board of the BSS.

In one embodiment of the present invention, the step (B) of gaining access to the broadband scheduled service provided by at least one broadband satellite system (BSS) by using at least one spot beam being tracked further comprises the following steps: (Bl) gaining access to a spot beam having a bandwidth (BW) by using a forward data link having frequency f_forward_i_ink at a first data rate First_bits_ per_second and using a return data link having frequency f_{retUrn l}i_nk ^at a second data rate Second_bits_ per_second; wherein the spot beam provides access to N communication channels; and (B2) downloading a set of data during a time period T.

In one embodiment of the present invention, the step (B2) of downloading the set of data during the time period T further comprises the step (B2, 1) of downloading a set of data selected from the group consisting of: {detailed weather maps,- news and sports programs; and movies} .

In one embodiment of the present invention, the method comprises the following steps: (A) using a satellite antenna of the first ship satellite tracking station (SSTS) to perform tracking of at least one spot beam generated by the BSS; (B) gaining access to at least one broadband satellite system (BSS) by the first ship,- (C) using a satellite antenna of the second ship satellite tracking station (SSTS) to perform tracking of at least one spot beam generated by the BSS; (D) gaining access to at least one broadband satellite system (BSS) by the second ship; and (E) using at least one broadband satel- lite system (BSS) to exchange data between the first ship and the second ship.

The foregoing description of specific embodiments of the present invention has been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims

ClaimsWhat is claimed is:

1. A method of providing a cost-effective two-way- maritime broadband service to at least one ship located in a predetermined shipping channel, said method comprising the steps of:

(A) providing at least one broadband satellite system (BSS) ; wherein each said BSS generates at least one spot beam; and wherein each said BSS satellite is configured to provide a broadband service;

(B) scanning at least one predetermined shipping channel by said at least one spot beam generated by at least one said broadband satellite system (BSS) ; and

(C) providing a broadband scheduled service for each said ship located in said shipping channel .

2. The method of claim 1, wherein said step (A) of providing at least one said broadband satellite system

(BSS) further comprises the step of:

(Al) providing at least one said broadband satellite system (BSS) , wherein each said BSS generates a spot beam covering said at least one predetermined shipping channel.

3. The method of claim 1, wherein said step (A) of providing at least one said broadband satellite system

(BSS) further comprises the step of: (A2) providing at least one said broadband satellite system (BSS) , wherein each said BSS generates a plurality of independent scanning spot beams covering said at least one predetermined shipping channel .

4. The method of claim 1, wherein said step (A) of providing at least one said broadband satellite system

(BSS) further comprises the step of:

(A3) providing a multibeam network of BSS, wherein each said BSS generates a single spot beam; and wherein said multibeam network of BSS generates a plurality of spot beams covering said at least one predetermined shipping channel, and wherein said plurality of spot beams is used to provide a broadband service with broadened schedule.

5. The method of claim 1, wherein said step (B) of scanning at least one predetermined shipping channel by said at least one spot beam generated by at least one said broadband satellite system (BSS) further comprises the steps of :

(Bl) determining a service zone contour within said at least one predetermined shipping channel;

(B2) determining a geometrical contour including said service zone within said at least one predetermined shipping channel as seen from said at least one BSS satellite; and

(B3) steering a BSS transmitting and receiving means to scan an area within said geometrical contour including said service zone within said at least one predetermined shipping channel by said at least one spot beam of said BSS.

6. The method of claim 5, wherein said transmitting and receiving means comprises a BSS antenna; and wherein said step (B3) of steering said BSS transmitting and receiving means to scan said area within said geometrical contour including said service zone within said at least one predetermined shipping channel further comprises the step of: (B3, 1) mechanically steering said BSS antenna by using a mechanical means located on board of said BSS.

7. The method of claim 5, wherein said transmitting and receiving means comprises a phase-array BSS antenna; and wherein said step (B3) of steering said BSS transmitting and receiving means to scan said area within said geometrical contour including said service zone within said at least one predetermined shipping channel further comprises the step of:

(B3, 2) electronically steering said phase-array BSS antenna by using an electronic means located on board of said BSS.

8. The method of claim 1, wherein said step (B) of scanning said at least one predetermined shipping channel by said at least one spot beam generated by at least one said broadband satellite system (BSS) further comprises the step of: (B4) scanning at least one said predetermined shipping channel by at least one spot beam generated by at least one broadband satellite system (BSS) for a predetermined time duration.

9. The method of claim 1, wherein said step (B) of scanning at least one predetermined shipping channel by said at least one spot beam generated by at least one said broadband satellite system (BSS) further comprises the step of: (B5) scanning at least one said predetermined shipping channel by at least one spot beam generated by at least one broadband satellite system (BSS) at a predetermined scanning rate.

10. The method of claim 1, wherein said step (C) of providing said broadband scheduled service for each said ship located in said at least one shipping channel further comprises the step of: (Cl) providing said broadband scheduled service in Ka band.

11. A method of utilizing a broadband scheduled service provided by at least one broadband satellite system (BSS) to at least one ship located within at least one predetermined shipping channel, each said ship being equipped with a ship satellite tracking station (SSTS) comprising a tracking satellite antenna; said method comprising the steps of: (A) performing tracking of at least one spot beam generated by said BSS by using said satellite antenna of said at least one ship satellite tracking station (SSTS) ; and

(B) gaining access to said broadband scheduled service provided by said at least one broadband satellite system (BSS) by using said at least one spot beam being tracked.

12. The method of claim 11, wherein said step (B) of gaining access to said broadband scheduled service provided by said at least one broadband satellite system (BSS) by using said at least one spot beam being tracked further comprises the steps of:

(Bl) gaining access to a spot beam having a bandwidth (BW) by using a forward data link having frequency f_{forward link} at a first data rate First_bits_ per_second and using a return data link having frequency f_retum_ii_nk ^{at a} second data rate Second_bits_ per_second; wherein said spot beam provides access to N communication channels/ and (B2) downloading a set of data during a time period T.

13. The method of claim 12, wherein said step (B2) of downloading said set of data during said time period T further comprises the step of:

(B2, 1) downloading a set of data selected from the group consisting of: {detailed weather maps; news and sports programs; and movies}.

14. A method of exchanging data between at least two ships located within at least one shipping channel by utilizing a broadband scheduled service provided by at least one broadband satellite system (BSS) , each said ship being equipped with a ship satellite tracking station (SSTS) comprising a tracking satellite antenna; said method comprising the steps of:

(A) using a satellite antenna of a first said ship satellite tracking station (SSTS) to perform tracking of at least one spot beam generated by said BSS;

(B) gaining access to said at least one broadband satellite system (BSS) by said first ship;

(C) using a satellite antenna of a second said ship satellite tracking station (SSTS) to perform tracking of at least one spot beam generated by said BSS;

(D) gaining access to said at least one broadband satellite system (BSS) by said second ship; and

(E) using said at least one broadband satellite system (BSS) to exchange data between said first ship and said second ship.

15. A system for providing a cost-effective two-way- maritime broadband service to at least one ship located in a predetermined shipping channel, said system comprising: (A) a broadband satellite system (BSS) means for generating at least one spot beam;

(B) a means for scanning at least one predetermined shipping channel by said at least one spot beam; and

(C) a means for providing a broadband scheduled service for each said ship located in said shipping channel .

16. The system of claim 15, wherein said broadband satellite system (BSS) means (A) for generating at least one spot beam further comprises:

(Al) at least one said broadband satellite system (BSS) , wherein each said BSS generates a spot beam covering said at least one predetermined shipping channel .

17. The system of claim 15, wherein said broadband satellite system (BSS) means (A) for generating at least one spot beam further comprises:

(A2) at least one said broadband satellite system (BSS) , wherein each said BSS generates a plurality of independent scanning spot beams covering said at least one predetermined shipping channel .

18. The system of claim 15, wherein said broadband satellite system (BSS) means (A) for generating at least one spot beam further comprises:

(A3) a multibeam network of BSS, wherein each said BSS generates a single spot beam; and wherein said multibeam network of BSS generates a plurality of spot beams covering said at least one predetermined shipping channel, and wherein said plurality of spot beams is used to provide a broadband service with broadened schedule.

19. The system of claim 15, wherein said means (B) for scanning at least one predetermined shipping channel by said at least one spot beam further comprises :

(Bl) a means for determining a service zone contour within said at least one predetermined shipping channel in a satellite-centered coordinate system;

(B2) a means for determining a geometrical contour including said service zone within said at least one predetermined shipping channel as seen from said at least one BSS satellite; and

(B3) a means for steering a BSS transmitting and receiving means to scan an area within said geometrical contour including said service zone within said at least one predetermined shipping channel by using said at least one spot beam of said BSS.

20. The system of claim 19, wherein said transmitting and receiving means comprises a BSS antenna; and wherein said means (B3) for steering said BSS transmitting and receiving means to scan said area within said geometrical contour including said service zone within said at least one predetermined shipping channel further comprises : (B3, 1) a mechanical means for steering said BSS antenna .

21. The system of claim 19, wherein said transmitting and receiving means comprises a phase- array BSS antenna; and wherein said means (B3) for steering said BSS transmitting and receiving means to scan said area within said geometrical contour including said service zone within said at least one predetermined shipping channel further comprises :

(B3 , 2) an electronic means for steering said phase- array BSS antenna.