阅读说明：本技术 太阳同步轨道 (Sun synchronous rail ) 是由 R·沃恩 J·斯科特 R·里德 R·霍金斯 J·萨利文 于 2018-04-09 设计创作，主要内容包括：卫星系统可以具有通信卫星星群,其通过诸如便携式电子设备和家庭/办公装置的电子设备向用户提供服务。网络操作中心可以使用网关来与卫星星群进行通信。卫星星群可包括具有不同轨道(诸如具有不同倾角的圆形轨道)的卫星集合、具有椭圆形轨道的卫星集合、具有不同高度的圆形轨道(包括低地球轨道、中地球轨道和/或地球同步轨道)的卫星集合、具有太阳同步轨道的卫星集合、和/或具有其他轨道的卫星集合。可以选择星群中的卫星的轨道以便向地球上的不同位置处的期望用户群体集中提供覆盖,同时减小在一天中的一个或多个时间未使用(例如,空闲)的容量。(Satellite systems may have a constellation of communication satellites that provide services to users through electronic devices such as portable electronic devices and home/office equipment. The network operations center may use gateways to communicate with the constellation of satellites. The constellation of satellites may include a set of satellites having different orbits, such as circular orbits with different inclinations, a set of satellites having elliptical orbits, a set of satellites having circular orbits of different heights, including low earth orbit, medium earth orbit, and/or geosynchronous orbit, a set of satellites having sun-synchronous orbits, and/or a set of satellites having other orbits. The orbits of the satellites in the constellation can be selected to provide coverage to a desired user constellation at different locations on earth while reducing unused (e.g., free) capacity at one or more times of day.)

1. A satellite constellation, the satellite constellation comprising:

a first set of communication satellites, wherein each of the communication satellites in the first set of communication satellites is characterized by an inclined circular orbit having a first inclination;

a second set of communication satellites, wherein each of the communication satellites in the second set of communication satellites is characterized by an inclined circular orbit having a second inclination that is different from the first inclination; and

a third set of communication satellites having sun-synchronized orbits, wherein the third set of satellites having sun-synchronized orbits are configured to provide communication capacity to a geographic area during a predetermined time of day.

2. The satellite constellation of claim 1, wherein the predetermined time of day comprises a daytime period.

3. The satellite constellation of claim 1, wherein the predetermined time of day comprises a time period after dark.

4. The satellite constellation of claim 1, wherein the predetermined time of day comprises a high demand time of day.

5. The satellite constellation of claim 1, wherein the communication satellites in the first set of communication satellites are characterized by low earth orbits.

6. The satellite constellation of claim 5, wherein the communication satellites in the second set of communication satellites are characterized by low earth orbits.

7. The satellite constellation of claim 6, wherein the communication satellites in the third set of communication satellites are characterized by low earth orbits.

8. The satellite constellation of claim 7, further comprising a fourth set of communication satellites having a medium earth orbit.

9. The satellite constellation of claim 7, further comprising a fourth set of communication satellites having a tilted geosynchronous orbit.

10. The satellite constellation of claim 1, wherein the first set of communication satellites comprises:

a first set of one or more low-earth orbit satellites having a first orbital height; and

a second set of one or more low-Earth orbit satellites having a second orbital altitude that is different from the first orbital altitude.

11. The satellite constellation of claim 10, wherein the third set of communication satellites having sun-synchronous orbits comprises:

a first set of communication satellites orbiting in a first sun-synchronous orbital plane; and

a second set of communication satellites orbiting in a second sun synchronous orbital plane different from the first sun synchronous orbital plane.

12. The satellite constellation of claim 11, wherein at a particular time of day, the first set of communication satellites in the first sun-synchronized orbital plane provide different geographic coverage than the second set of communication satellites in the second sun-synchronized orbital plane.

13. A satellite constellation, the satellite constellation comprising:

a plurality of communication satellites having circular orbits with an inclination of 10 ° -60 °, wherein the plurality of communication satellites includes a first set of communication satellites, wherein each of the communication satellites in the first set of communication satellites is characterized by an inclined circular orbit having a first inclination, wherein the plurality of communication satellites includes a second set of communication satellites, wherein each of the communication satellites in the second set of communication satellites is characterized by an inclined circular orbit having a second inclination, the second inclination being different from the first inclination; and

a third set of communication satellites having sun-synchronized orbits configured to provide communication capacity to a geographic area during a predetermined time of day.

14. The satellite constellation of claim 13, wherein the first set of communication satellites has a low earth orbit and the second set of communication satellites has a low earth orbit.

15. The satellite constellation of claim 14, further comprising at least one geosynchronous communication satellite.

16. The satellite constellation of claim 14, further comprising at least one medium earth orbit communications satellite.

17. The satellite constellation of claim 13, further comprising at least one communication satellite having a geostationary orbit.

18. The satellite constellation of claim 14, wherein the plurality of communication satellites having the circular orbit further comprises:

a fourth set of communication satellites in low earth orbit having a third orbital inclination different from the first orbital inclination and the second orbital inclination; and

a fifth set of communication satellites in low earth orbit having a fourth orbital inclination different from the first, second, and third orbital inclinations.

19. A satellite system, the satellite system comprising:

a satellite constellation, the satellite constellation having at least:

a set of sun-synchronous communication satellites having sun-synchronous orbits configured to provide communication capacity to a geographic area during a predetermined time of day; and

a first set of Low Earth Orbit (LEO) communication satellites having orbital inclination angles less than 70 °;

a second set of Low Earth Orbit (LEO) communication satellites having orbital inclination angles less than 65 °; and

a network operations center configured to control the constellation of satellites.

20. The satellite system of claim 19, further comprising:

a gateway configured to route communications between the network operations center and the satellite constellation.

Technical Field

The present disclosure relates generally to satellite systems for communications, including the use of sun-synchronized orbits to provide coverage during periods of high demand.

Background

Communication systems typically use satellites to transmit data. Satellite-based systems allow wireless transfer of information across long distances, such as the ocean. For example, satellite-based systems may be used to transfer information to terrestrial-based equipment, such as handheld devices and home or office equipment. Additionally, satellite communication systems may be used to provide coverage in the event that physical infrastructure is not already installed and/or to mobile devices that do not remain attached to infrastructure resources.

Implementing an efficient satellite-based communication system can be challenging. If not noticed, satellite deployment may be inefficient, resulting in increased cost and poor ground coverage. Additionally, if the satellite-based communication system is designed to service periods of highest demand, resources may remain idle during periods of lower demand. Furthermore, conventional satellite-based communication systems designed for specific demand levels may not be able to dynamically increase capacity in response to higher demand.

Disclosure of Invention

A satellite system may have a constellation of satellites of communication satellites that provide services (e.g., voice and/or data services) to electronic devices such as portable electronic devices and home/office equipment. The network operations center may use gateways to communicate with the constellation of satellites.

A satellite constellation may include a set of one or more satellites, where each set has a different orbit. For example, a satellite constellation may include any/all of the following: a set of satellites including circular orbits with different inclinations, a set of satellites with elliptical orbits, a set of satellites with circular orbits of different altitudes including Low Earth Orbit (LEO), Medium Earth Orbit (MEO) and/or geosynchronous orbit (e.g., highly inclined geosynchronous orbit), sun-synchronous orbit (tss), and/or other sets of satellites.

The orbits of the satellites in the constellation of satellites may be selected to improve service efficiency. For example, one or more orbits may be selected to focus coverage at the center of a user population at various locations on the earth. Additionally or alternatively, one or more tracks may be selected to accommodate demand peaks that coincide with specific times of day. Such a design may help reduce the number of satellites needed to provide a desired amount of coverage.

Drawings

Fig. 1 presents a diagram of an exemplary communication system including a satellite, in accordance with some embodiments.

Fig. 2 presents a schematic diagram illustrating an example of an electronic device in communication with a communication satellite, in accordance with some embodiments.

Fig. 3 presents a diagram of an exemplary satellite orbit around the earth, in accordance with some embodiments.

Figure 4 presents an illustration of earth and associated tilted satellite orbits, according to some embodiments.

Fig. 5 presents a graph in which an exemplary data traffic demand curve is plotted as a function of time of day, according to some embodiments.

Detailed Description

The present disclosure, including the figures, is illustrated by way of example and not by way of limitation.

The communication network may include one or more communication satellites and other devices, including ground-based communication devices and user terminals (or User Equipment (UE)). One or more satellites may be used, for example, to deliver wireless services to portable electronic devices, home and/or office equipment, and other equipment. For example, wireless services may be provided to handheld devices, wearable devices, set-top boxes, media devices, mobile terminals, computing devices, sensors, and the like. An exemplary communication system with satellites is shown in fig. 1. As shown in fig. 1, system 10 may include one or more constellations of communication satellites 22. The satellites 22 may be placed in any/all of a Low Earth Orbit (LEO) around the earth 12 (e.g., at an altitude of 500km-1500km or other suitable altitude), a geosynchronous orbit, and/or a Medium Earth Orbit (MEO). The satellites 22 may form a constellation of satellites having one or more sets of satellites with different types of orbits, e.g., synchronized with each other to provide a desired amount of coverage to a user population (or geographic area). Any suitable number of satellites 22 may be present in one or more of the satellite constellations of the system 10 (e.g., 10-100, 1,000-10,000, greater than 100, greater than 1000, less than 10,000, etc.).

The satellite 22 may deliver wireless services to devices such as the electronic device 18. The electronic devices 18 may include handheld devices and/or other mobile devices, such as cellular phones, tablet computers, laptop computers, watches, and other wearable devices, mobile terminals, drones, robots, and other portable electronic devices. The electronic equipment 18 may also include fixed (or less portable) devices such as set-top boxes (e.g., satellite receivers), routers, home base stations, televisions, desktop computers, ground terminals (e.g., gateways), and other electronic devices. The electronic device 18 may be located anywhere on or above the earth, for example, on land, at sea, or in the air. The services provided by the satellite 22 may include telephony (voice) services, broadband internet access, media distribution services such as satellite audio (satellite radio and/or streaming audio services) and satellite television (video), data communications, positioning, and/or other services.

System 10 may include one or more Network Operations Centers (NOCs), such as NOC16, which may be coupled to one or more gateways (e.g., gateway 14). Any suitable number of gateways 14 may be present in system 10 (e.g., 1-100, greater than 10, greater than 100, less than 1000, etc.). The gateway 14 may have transceivers that allow the gateway to transmit wireless signals to the satellite 22 over the wireless link 20 and to receive wireless signals from the satellite 22 over the wireless link 20. The wireless link 20 may also be used to support communication between the satellite 22 and the electronic device 18. For example, during a media distribution operation, the gateway 14 may send traffic to a given satellite 22 via an uplink (one of the links 20) and then route it to one or more electronic devices 18 via a downlink (one of the links 20). Gateway 14 may perform various services including provisioning media for electronic device 18, routing telephone calls (e.g., voice and/or video calls) between electronic device 18 and/or other devices, providing internet access for electronic device 18, and/or delivering other communication and/or data services to electronic device 18. Gateways 14 may communicate with each other via satellites 22 and/or using a ground-based communication network.

NOC16 may be used to manage the operation of one or more gateways 14 and/or the operation of one or more satellites 22. For example, the NOC16 may monitor network performance and take appropriate corrective action if necessary. During these operations, the NOC16 may update software for one or more satellites 22 and/or electronic devices 18, may adjust the altitude and/or other orbital parameters of the satellites 22, may instruct one or more satellites 22 to perform operations that adjust satellite solar panels and/or other satellite components, and/or may otherwise control and maintain one or more satellites 22 in a constellation of satellites orbiting the earth 12. Additionally, in some embodiments, the NOC16 may also be configured to perform maintenance operations on one or more gateways 14.

The gateway 14, satellite 22, NOC16, and electronic device 18 may be configured to support encrypted communications. For example, the NOC16 and the gateway 14 may communicate using encrypted communications. Similarly, the gateway 14, satellite 22, and electronic device 18 may communicate using encrypted communications. This allows the NOC16 to issue security commands and receive security information when communicating with the gateways 14, satellites 22, and/or electronic devices 18. The use of encrypted communications within system 10 also allows electronic devices 18 to securely communicate with each other and with gateway 14, and also allows gateway 14 to securely distribute media and/or other information to electronic devices 18, for example, in accordance with digital protection requirements.

During operation of the system 10, the satellites 22 may serve as orbital relays. For example, when gateway 14 transmits wireless uplink signals, one or more satellites 22 may forward these signals as downlink signals to one or more electronic devices 18. In some embodiments, some electronic devices 18 may be receive-only devices, while other electronic devices 18 may support two-way communication with satellites. Where the electronic device 18 supports two-way communication, the electronic device 18 may transmit wireless signals to one or more satellites 22 so that the one or more satellites 22 may relay this information to one or more appropriate destinations (e.g., the gateway 14, other electronic devices 18, etc.).

The satellites 22 and links 20 may support any suitable satellite communication frequency band (e.g., IEEE frequency band), such as an L-band (1GHz-2GHz), an S-band (2GHz-4GHz), a C-band (4GHz-8GHz), a Ka-band (27GHz-40GHz), a V-band (40GHz-75GHz), a W-band (75GHz-110GHz), and/or other frequency bands suitable for spatial communication (e.g., frequencies above 1GHz, below 110GHz, and/or other suitable frequencies).

Some frequencies (e.g., C-band frequencies and other low frequencies, such as L-band and S-band frequencies) may penetrate buildings and thus may be suitable, at least at some times, for communicating with electronic devices located indoors, such as handheld electronic devices 18 (e.g., devices that are mobile and may sometimes be indoors and may sometimes be outdoors) and/or electronic devices 18 without external antennas/receivers. Other frequencies (e.g., V-band frequencies and other high frequencies, such as Ka-band and W-band frequencies) cannot easily (or efficiently) penetrate buildings and thus may be suitable for communication with electronic devices 18 having external antennas/receivers or being positioned outdoors and/or otherwise having line-of-sight paths to satellites 22. To accommodate various scenarios (e.g., mobile device scenarios and home/office scenarios), the satellites 22 may include, for example, C-band satellites (or other low-band satellites, such as L-band or S-band satellites), V-band satellites (or other high-band satellites, such as Ka-band or W-band satellites), and/or dual-band satellites (e.g., satellites that support C-band and V-band communications or other low-band and high-band communications).

In at least some embodiments, demand for communication services can be expressed as a function of location and time of day. For example, densely populated areas (e.g., cities) may have higher demand than less populated areas (e.g., mountain areas and/or rural areas). Additionally, demand in a given region may not be constant throughout the day, for example, because user activities/demands (individual and/or as a group) such as business and social activities may vary throughout the day. Thus, the demand for communication services during one or more periods of the day may be greater than the demand at other times of the same day, e.g., evening time versus late night time.

Depending on how significant the demand varies throughout the day, it may not be sufficient to achieve a constellation that meets the capacity demand during peak busy hours and has reduced utilization for the remainder of the day. Rather, the constellation may be implemented by providing one or more assets of "surge" capacity, e.g., additional capacity relative to the baseline capacity that is available only during one or more higher demand periods of the day (e.g., during a predetermined daytime period, during a predetermined period after sundark, during a high demand period, such as from 7PM to 10PM, etc.). In some embodiments, this surge capacity may be achieved using one or more satellites in sun-synchronized orbits, wherein the sun-synchronized satellites provide coverage over a particular area during periods of high demand. Thus, a constellation can be constructed to provide a lower average capacity level throughout the day while utilizing a small number of satellites (e.g., sun-synchronized orbits) to effectively meet demand in a particular area during a particular period of increased demand.

The sun-synchronous orbit may be implemented as a near-polar orbit, with the altitude and inclination of the satellite configured such that the nodal regression rate matches the orbit rate of the earth and thus during each orbit, the sun-synchronous satellite crosses the equator at the same local time of day. Thus, the sun sync satellite passes over each day at the same time of day relative to the ground. By using sun-synchronized tracks, a geographic area can be supplied with variable capacity to meet demand based on time of day changes. Thus, the orbital plane may be selected such that during periods of increased demand (e.g., during peak traffic time divisions), one or more satellites pass through the region each day. Thus, the constellation configuration can provide increased (e.g., peak) capacity where and when needed, without increasing the capacity of the constellation at all times and locations. Thus, a reduced number of satellites may be used to implement the constellation, which reduces the cost of the constellation, the number of transmissions required to implement the constellation, and the time required to bring the services of the constellation to market, among other advantages. The constellation of satellites including sun sync satellites provides an economical means to supplement other orbits to meet global service with daily time of day demand cycles. For example, using satellites in sun-synchronized orbits in this manner can effectively double the constellation capacity while only increasing the number of satellites by about 30%.

Fig. 2 presents a schematic view of an illustrative electronic device 18 in communication with an illustrative satellite 22 via a wireless communication link 20. As shown in fig. 2, the electronic device 18 may include one or more antennas 30. The antenna 30 may include monopole, dipole, and/or other types of antenna elements. The antenna 30 may include, for example, a loop antenna, a spiral antenna, a patch antenna, an inverted-F antenna, a yagi antenna, a slot antenna, a horn antenna, a cavity antenna, a dish antenna, an antenna array (e.g., a phased antenna array that supports beam steering operation), or other suitable antenna. The antennas 30 may be implemented such that they are suitable for communicating with one or more satellites using one or more satellite communication frequency bands. The radio-frequency transceiver circuitry 32 may include radio-frequency receiver circuitry and/or radio-frequency transmitter circuitry that allows the electronic device 18 to transmit and/or receive wireless signals over the wireless communication link 20 using the one or more antennas 30. The electronic device 18 may also include control circuitry 34 and an input-output device 36. The control circuit 34 may include storage devices such as solid state drives, random access memory, and/or hard disk drives as well as other volatile and/or non-volatile memory. The control circuitry 34 may also include one or more microcontrollers, microprocessors, digital signal processors, communication circuitry with a processor, application specific integrated circuits, programmable logic devices, field programmable gate arrays, and/or other processing circuitry. During operation, the control circuit 34 may execute code (instructions) stored in a memory device of the control circuit 34 to implement desired functions of the electronic device 18.

Control circuitry 34 may use input-output device 36 to supply output to an interface configured to make the output perceptible to a user and/or to an external device, and may collect input received from a user and/or one or more external sources. Input-output devices 36 may include a display configured to present images, audio devices (e.g., speakers and/or microphones), sensors, controls, and other components. For example, the input-output devices 36 may include user input devices such as one or more buttons, a touch screen, sensors (e.g., an accelerometer and/or a gyroscope), a microphone for collecting voice commands, and/or other components for collecting input from a user. In addition, input-output devices 36 may include speakers, light emitting components, displays, vibrators, and/or other tactile output devices, as well as other means for supplying output to a user. Input-output devices 36 may include sensors such as force sensors, position sensors, gyroscopes, magnetic sensors, accelerometers, capacitive touch sensors, proximity sensors, ambient light sensors, temperature sensors, humidity sensors, gas sensors, pressure sensors, and other sensors for collecting information indicative of the environment in which electronic device 18 is located.

A satellite, such as satellite 22, may include one or more antennas 40. The antenna 40 may be based on any suitable type of antenna element (e.g., an antenna element such as a monopole or dipole, a loop antenna, a helix antenna, a patch antenna, an inverted-F antenna, a yagi antenna, a slot antenna, a horn antenna, a cavity antenna, etc.). The antenna 40 may be used with any suitable type of antenna array (e.g., a phased antenna array, a fixed direct radiating array, an expandable direct radiating antenna array, a spatial feed array, a reflector feed array, etc.). Antennas 40 may be implemented such that they are suitable for communicating with one or more electronic devices 18, gateways 14, or other communication devices/nodes using one or more satellite communication frequency bands.

Satellite 22 may include transceiver circuitry communicatively coupled (directly or indirectly) to antenna 40. The transceiver circuitry may include one or more components, such as one or more repeaters 42 for receiving uplink signals and transmitting downlink signals, for example, on the link 20. Additionally, the control circuitry 44 may be used to control the operation of the satellites 22. Control circuitry 44 may include storage and/or processing circuitry of the type used in control circuitry 34.

Power may be supplied to the satellites 22 from a power system 46. The power system 46 may include one or more solar panels 48 (or an array of solar panels) for converting energy from the sun into electricity. The power system 46 may include power regulator circuitry and batteries for storing power generated by the solar panels 48 and distributing the power to the components of the satellite 22. The control circuitry 44 may receive information from one or more sensors 50. Additionally, the control circuitry 44 may receive commands from the NOC16, and, using information from one or more sensors and/or the received commands, may perform maintenance and/or control operations (e.g., software updates, operations related to the deployment and operation of the solar panels 48, diagnostic routines, height adjustments, and other track adjustments using the propulsion system 52, etc.). The sensors 50 may include light-based sensors (e.g., infrared cameras, visible light cameras, etc.), lidar, radar, sensors that measure backscattered light and/or backscattered radio frequency signals, temperature sensors, radiation sensors, accelerometers, gyroscopes, magnetic sensors, spectrometers, and/or other sensors. The sensors 50 may be used to perform telemetry, fault detection, satellite positioning, and other operations.

It may be desirable for the constellation of satellites 22 in system 10 to include satellites having different types of orbits. As an example, the satellites 22 may include orbits having different altitudes, eccentricities, inclinations, and other orbital attributes. One or more sun-synchronized satellites (or satellites in sun-synchronized orbit) may be included in the constellation of satellites 22 in system 10. One or more sun syncs can be configured to help meet demand (e.g., measured in throughput, number of simultaneous connections, or other such metrics) during periods of high demand, such as during afternoon or night time periods. By combining different orbit types within the same satellite constellation, the efficiency of deploying satellite resources may be improved.

Fig. 3 is a diagram of two exemplary satellite orbits (geocentric orbits) around the earth 12. The satellites 22 may orbit in a circular orbit (as shown in the schematic circular orbit 56) or in an elliptical orbit (such as the elliptical orbit 58). The circular orbit is characterized by an eccentricity of 0. The eccentricity of the elliptical orbit is greater than 0.

As shown in fig. 3, a satellite in circular orbit is characterized by an orbital height a. The satellites 22 may orbit at any altitude suitable for their intended purpose. For example, the satellites 22 may orbit the earth 12 in a low earth orbit (e.g., at an altitude a of 500km-1500 km), a geosynchronous orbit (e.g., at an altitude a of about 35,800 km), or a medium earth orbit (e.g., between a low earth orbit and a geosynchronous orbit). Examples of medium earth orbits include semi-synchronous orbits and Molniya orbits. The height of the semi-synchronous orbit is about 20,000km and is characterized by an orbital period that is half of a sidereal day. The Molniya orbit has an eccentricity greater than zero and has a near-earth position in the southern hemisphere, so satellites in this type of orbit spend most of their orbital time over the northern hemisphere, and vice versa. The Tundra orbit is an elliptical orbit (with an eccentricity greater than zero) with an orbit period twice that of the Molniya orbit. Other elliptical orbits (e.g., orbits having an eccentricity of at least 0.3, at least 0.5, at least 0.7, less than 0.8, etc.) can be used if desired.

The satellite may have a tilted circular orbit (a circular orbit located outside the equatorial plane) if desired. For example, consider satellite 22 of FIG. 4. In the illustration of fig. 4, a satellite 22 orbits the earth 12 in a satellite orbital plane SP. The plane SP is inclined at an inclination angle (tilt angle) I with respect to an equatorial plane EP aligned with the earth's equator. Polar tracks (sometimes referred to as near-polar tracks) are tracks that pass through north and south poles and are therefore characterized by an inclination of about 90 ° (e.g., at least 85 °, at least 88 °, at least 89 °, 90 °, less than 90 °, or other suitable polar track inclination).

One or more satellites 22 in the constellation of satellites of system 10 may have sun-synchronized orbits. A sun-synchronous orbit (sun-synchronous orbit) is a polar orbit (near-polar orbit) that passes the equator (or other given latitude) at the same local time each day. The elevation and dip of the sun's synchronous orbit are such that the nodal regression rate matches the earth's orbital rate. Thus, for users on the ground, the sun syncs will pass over each day at the same time of day. Because satellites with sun-synchronized orbits can be used to process communication traffic at the same local time each day, including one or more sun-synchronized satellites in the satellite constellation of system 10 can help the satellite constellation to efficiently meet peak traffic demands.

In general, each type of orbit included in the constellation of satellites of system 10 may help enhance the performance of the constellation in a different manner. For example, an elliptical orbit (such as a Molniya or Tundra orbit) may be used to provide capacity to a user population center (e.g., a population center located in europe, north america, australia, or asia) at a particular longitude and/or latitude (or one or more ranges thereof) of a northern hemisphere or a southern hemisphere. Additionally, a sun-synchronized orbit may be used to provide capacity that is concentrated at one or more high demand times of the day (e.g., morning or evening). The inclined circular track may be used to provide coverage over a desired range of latitudes. Low earth orbit may help reduce latency (e.g., for traffic related to voice telephone calls and other communications that are delay sensitive), and may help reduce transmit and receive power. Medium and geosynchronous orbits may help increase coverage, reduce the total number of satellites required to serve a given area, and may be well suited for broadcast-type traffic (e.g., media distribution services such as television services, music services, etc.).

As an example, consider an arrangement in which a set of a plurality of satellites 22 is included in a constellation of satellites, each set of satellites having a circular low earth orbit with a different respective orbital inclination. The coverage (probability density) of the inclined orbits is concentrated at the inclination angle I (e.g., + I in the northern hemisphere and-I in the southern hemisphere). Thus, if there is a first user population at 55 ° and a second user population at 48 ° (as an example), the satellite constellation may effectively serve the user populations at both latitudes by including at least a first set of satellites having an orbital inclination of 55 ° and a second set of satellites having an orbital inclination of 48 °. If desired, a set of one or more satellite(s) with different respective orbital inclinations may be included (e.g., one or more additional sets, two or more additional sets, 2-5 additional sets, 3-10 additional sets, etc., where each set includes one or more satellites).

In addition to accommodating one or more user population sets, e.g., at a particular latitude (e.g., a latitude associated with a metropolitan area), by forming the satellite constellation of system 10 from a plurality of sets of satellites 22, each set of satellites having a different respective orbital inclination, the satellite constellation of system 10 can include one or more sun-synchronized satellites 22 to accommodate traffic peaks (e.g., measured in terms of throughput, number of simultaneous connections, etc.) at one or more high-demand times of day.

As an example, consider the schematic traffic flow versus time of day curve of fig. 5 (curve 80). As shown in fig. 5, the communication services provided by the constellation of satellites of system 10 may experience significant changes in demand throughout the day. The services provided by system 10 may include, for example, any/all of voice and video call services, data services, and media distribution services (television, audio, etc.). During the early morning hours, when the user is mostly asleep, the demand is low (see, e.g., low demand period 84 of curve 80 of FIG. 5). As the user population wakes up, the demand for communication tends to rise. In at least some embodiments, data traffic (voice, internet, media distribution, etc.) may increase at night time and may peak, for example, when a user coming home from work begins watching television, communicating, accessing social media, and consuming other media/content. For example, as shown by peak 82 of curve 80, the demand for communication services may increase (and may peak) between approximately 5PM and 10PM during the night.

Using one or more sun-synchronized satellites configured to pass above during times of day associated with high (e.g., peak) demand, demand in a geographic area that increases (or peaks) at particular times of day may be efficiently accommodated. To accommodate the increased traffic during the time of day, such as peak 82 of fig. 5, for example, the satellite constellation of system 10 may include one or more sun-synchronized satellites that traverse a particular latitude or range of latitudes (e.g., northern hemisphere latitudes) during periods of relatively high demand (e.g., 5PM to 10PM traffic peaks). As an example, the first set of solar geostationary satellites 22 may be used to provide additional coverage during periods of increased demand (e.g., about 5PM), and may pass above each day at times of increased demand (e.g., 5 PM). Depending on the duration of the additional coverage and the duration of the increased demand of the first set of solar geostationary satellites 22, one or more additional sets of solar geostationary satellites may be included in the constellation. For example, a second set of sun sync satellites 22 located in a different sun sync orbital plane than the first set of sun sync satellites 22 may be used to provide additional coverage during another period of increased demand (e.g., occurring around 7PM), and may pass above each day at times of increased demand (e.g., 7 PM). For example, additional sets of sun sync satellites, each in the same different sun sync orbital plane, may be used to address increased demand at other times, such as 8PM, 9PM, and/or 10PM (as examples). The number of sets of one or more sun sync satellites included in a constellation may be selected to correspond to periods and/or durations of increased demand in one or more areas served by the constellation. For example, in such embodiments, there may be, for example, six separate sun-synchronous orbital planes that are offset from each other, for example, one hour each. In some embodiments, the solar synchronous orbital plane may have a paraxial inclination (e.g., 97.6 ° or other suitable inclination), and may have a height of about 550km (e.g., greater than 500km, less than 600km, or other suitable height). There may be any suitable number of satellites 22 orbiting in each of the six sun-synchronous orbital planes (e.g., 3 to 10 satellites per aircraft, up to 50 satellites per aircraft, more than 25 satellites per aircraft, less than 100 satellites per aircraft, etc.). In some other embodiments, the sun-synchronous orbital planes may have different inclinations and/or heights. Additionally, in some embodiments, the inclination and/or altitude may differ between the set of satellites in the sun-synchronous orbital plane.

With this type of arrangement, for example, a sun-synchronized satellite may handle increased (e.g., peak) traffic T2, whereas other satellites in the constellation (e.g., low earth orbiting satellites having a range of different orbital inclinations (e.g., orbital inclinations less than 70 °, less than 65 °, etc.)) may be used to handle traffic T1. If desired, one or more geostationary satellites (e.g., geostationary satellites with inclined orbits), medium earth orbit satellites, and/or satellites with elliptical orbits may be included in a constellation to handle traffic concentrated at a particular geographic location (e.g., a particular longitude and latitude, such as eastern north america, etc.).

As these examples illustrate, combining a set of satellites with different orbital inclinations, a set of satellites in a sun-synchronous orbit (e.g., sun-synchronous orbit aligned with one or more increasing (e.g., peak) traffic periods during a day), a set of satellites in a geosynchronous orbit, and/or a set of satellites in a medium earth orbit (e.g., circular and/or elliptical) may effectively meet traffic demand without excessive satellite resources (e.g., resources that remain idle during other periods of the day).

Within the constellation of satellites 22 in the system 10, each set of satellites 22 sharing a common orbit (e.g., a common orbital inclination and altitude for a set of low earth orbiting satellites having circular orbits, a common elliptical orbit type for a set of medium earth orbiting satellites, a common sun synchronous orbit, geocentric orbit, etc.) may include any suitable number N of satellites 22. For example, N can be 1-100, 10-1000, 10-10,000, 20-500, at least 10, at least 50, at least 100, at least 200, less than 10,000, less than 1000, less than 500, less than 100, or other suitable number. In addition, the number of satellites 22 sharing a common orbit may be adjusted over time.

The satellites 22 in the satellite constellation may have the same type of antenna array (with the same type of antenna elements), may have different types of antennas (e.g., one type of antenna array may be used for low earth orbit satellites, another type of antenna array may be used for sun sync satellites, and another type of antenna array may be used for geosynchronous satellites), may have different types of power systems (e.g., different power sources, different numbers of solar panels per satellite, etc.), or may have a common type of power system (e.g., a power system having the same type and number of solar panels, etc.), may have different satellite buses, or may share a common satellite bus architecture, may have different propulsion systems, may share a common type of propulsion system, etc. The satellites in the constellation of satellites of system 10 may be communication satellites (e.g., satellites that handle voice and data traffic, audio and/or video media broadcasts (such as broadcasts of television traffic), and/or satellites that handle other suitable types of communication traffic). Different sets of satellites (with the same or different components) may have different eccentricities, altitudes (e.g., different circular orbital altitudes), inclinations, and/or other different orbital properties. For example, one, two, three, four, or five or more sets of satellites may have circular low earth orbits with different respective inclinations (e.g., 0 ° -80 °, 10 ° -60 °, 30 ° -60 °, greater than 30 °, less than 80 °, less than 60 °, less than 70 °, or other suitable inclination), and one, two, three, four, or five or more of these orbits may have an altitude below a given altitude, while one or more additional sets of satellites may have an altitude greater than the given altitude. One or more of these additional sets of satellites may be geosynchronous, if desired, and one or more of these additional sets of satellites may be characterized by a medium earth orbit. If desired, one or more sets of satellites having one or more different respective elliptical orbits (different respective eccentricities) can be included in the constellation of satellites. A set (group) of satellites with sun-synchronized orbits may be included to help accommodate one or more daily traffic peaks.

According to one embodiment, there is provided a satellite constellation comprising: a plurality of communication satellites having circular orbits with an inclination of 10-60, and at least one sun synchronous communication satellite having a sun synchronous orbit.

According to another embodiment, a plurality of communication satellites having circular orbits comprises: a first set of communication satellites in low earth orbit having a first orbital inclination; and a second set of communication satellites in low earth orbit having a second orbital inclination different from the first orbital inclination.

According to another embodiment, the satellite constellation includes at least one geosynchronous communication satellite.

According to another embodiment, the constellation of satellites includes at least one medium earth orbit communications satellite.

According to another embodiment, a satellite constellation includes at least one

A communication satellite having a geostationary orbit.

According to another embodiment, a plurality of communication satellites having circular orbits comprises: a third set of communication satellites in low earth orbit having a third orbital inclination different from the first orbital inclination and the second orbital inclination; and a fourth set of communication satellites in low earth orbit having a fourth orbital inclination different from the first, second and third orbital inclinations.

According to one embodiment, there is provided a satellite system comprising: a satellite constellation having at least a first set of sun-synchronous communication satellites having sun-synchronous orbits and a second set of low-earth orbit (LEO) communication satellites having orbital inclinations less than 70 °; and a network operations center configured to control the constellation of satellites.

According to another embodiment, a satellite system includes a gateway configured to route communications between a network operations center and a constellation of satellites.

According to another embodiment, the satellite constellation includes a third set of geosynchronous communication satellites having geosynchronous orbits.

According to another embodiment, the second set of LEO communication satellites includes a first set of communication satellites having a first orbital inclination, an

A second set of communication satellites having a second orbital inclination different from the first orbital inclination.

According to another embodiment, the second set of LEO communication satellites includes a third set of communication satellites having a third inclination of orbit that is different from the first inclination of orbit and the second inclination of orbit.

According to another embodiment, the second set of communication satellites includes a fourth set of communication satellites having a fourth orbital inclination different from the first orbital inclination, the second orbital inclination, and the third orbital inclination.

According to one embodiment, there is provided a satellite constellation comprising: a first set of communication satellites, each communication satellite in the first set of communication satellites characterized by an inclined circular orbit having a first inclination; a second set of communication satellites, wherein each communication satellite in the second set of communication satellites is characterized by an inclined circular orbit having a second inclination angle that is different from the first inclination angle; and a third set of communication satellites having sun-synchronous orbits.

According to another embodiment, the communication satellites included in the first, second, and third sets of communication satellites are characterized by low earth orbit.

According to another embodiment, the third set of satellites having sun-synchronized orbits is configured to provide communication capacity to the geographic area during a predetermined time of day.

According to another embodiment, the satellite constellation includes a fourth set of communication satellites having medium earth orbits.

According to another embodiment, the satellite constellation includes a fourth set of communication satellites having geosynchronous, tilted orbits.

According to another embodiment, the first set of communication satellites includes: a first set of one or more low-earth orbit satellites having a first orbital height; and a second set of one or more low earth orbit satellites having a second orbital height different from the first orbital height.

According to another embodiment, the third set of communication satellites having sun-synchronized orbits includes: a first set of communication satellites orbiting in a first sun-synchronous orbital plane; and a second set of communication satellites orbiting in a second sun synchronous orbital plane different from the first sun synchronous orbital plane.

According to another embodiment, at a particular time of day, a first set of communication satellites in a first solar synchronous orbital plane provides different geographic coverage than a second set of communication satellites in a second solar synchronous orbital plane.

The foregoing is merely exemplary and various modifications may be made to the embodiments. The foregoing embodiments may be implemented independently or in any combination.