• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The satellite system according to the invention intended for navigation and / or geodesy is provided with several MEO satellites respectively having their own clock which are distributed in orbits and which rotate around the Earth, several MEO satellites, in particular eight, lying in each orbit. In addition, the satellite system according to the invention is provided with several LEO satellites and / or several ground stations. Each MEO satellite has two optical terminals for the bidirectional transmission of optical free beam signals by means of lasers respectively with the first and / or second MEO satellite which precedes (s) directly on the same orbit and respectively the first and / or second satellite MOE following / following directly on the same orbit. With the aid of the optical free beam signals, the clocks of the MEO satellites are synchronized orbit by orbit with each other to give a valid orbit time for this orbit.
    公开号:FR3066610A1
    申请号:FR1854171
    申请日:2018-05-18
    公开日:2018-11-23
    发明作者:Christoph Gunther；Johann Furthner
    申请人:Deutsches Zentrum fuer Luft und Raumfahrt eV；
    IPC主号:
    专利说明:

    Satellite system for navigation and / or geodesy
    The invention relates to a satellite system for navigation and / or geodesy.
    Current satellite navigation systems transmit signals in the signal frequency
    The trajectories of are determined by ground measurements. These are also used for such as throws in addition to radio frequency range (L band). The is derived from an atomic clock.
    satellites and the arrangement of system clocks Some specific missions,
    GRACE, GOCE and LAGEOS, were geodesy.
    example for geodesy.
    The systems present some current navigation infrastructure to the current unidirectional satellite, navigation disadvantages.
    depend enough on satellite
    Thus, the systems of strongly of a current complex soil. Due in systems difficult to separate the due to the troposphere. The direction of navigation measures by it is quite time, the altitude and the trajectory component delays in particularly tricky to determine. The known ones are geodesy, but certainly used jointly they were not designed for that.
    flight is systems there for
    The object of the invention is to indicate a satellite navigation system improved in various respects which is designed to be also used in geodesy.
    .2
    To achieve this objective, the invention proposes a satellite system for navigation and for geodesy, the satellite system being provided with several MEO satellites (at an altitude of 10,000 km to 30,000 km) respectively having their own clock. which are distributed in orbits and which revolve around the Earth, several MEO satellites, in particular eight, being present in each orbit, and several LEO satellites and / or several ground stations, each MEO satellite having two terminals Optics for the bidirectional transmission of optical free beam signals by means of lasers with the first and / or second MEO satellite respectively preceding (s) in the same orbit and with the first and / or second MEO satellite respectively following / following on the same orbit and the clocks of the MEO satellites being, by means of the optical free beam signals, synchronized by orbit with each other s others to give a valid orbit time for this orbit.
    The invention provides a satellite system for navigation and geodesy in which several Medium Earth Orbit (MEO) satellites are used which rotate around the Earth being distributed over at least two, preferably three, orbits. In each orbit, there are several MEO satellites, and in particular eight. Between the MEO satellites of each orbit, there is a single or multiple optical link of respectively neighboring satellites with optical frequency standards, that is to say a time base with laser assistance. It is thus possible to establish a very stable system time scale with extremely high short-term stability if, which is advantageously provided, each MEO satellite has a laser stabilized on cavity or respectively on resonator with an optical resonator which forms the time base of the MEO satellite. On the Medium Earth Orbit, optical free beam communication is not subject to any influence exerted by the Earth's atmosphere so that it does not affect the accuracy of the orbit system time. Besides the very precise time reference system according to the invention, it is possible, with the proposal according to the invention, to establish a very precise reference system for space insofar as the trajectories are stable and are measured with great precision. By means of dedicated individual optical communication links from MEO satellites to LEO satellites and from these to ground stations or respectively directly from MEO satellites to ground stations, it is then possible to synchronize with reference systems located on the ground (for both time and space). With the satellite system according to the invention, the accuracy of the frequency and time synchronization as well as the measurements of distance to different objects in space and / or on Earth can, compared with the prior art, be determined with much higher precision with the satellite system according to the invention.
    In an advantageous development of the invention, it is provided that the clock of each MEO satellite has a laser stabilized on an optical cavity.
    .4
    In another suitable form of
    1'invention, it is possible to predict that the satellites
    MEO emit radio signals for navigation (for example in the band
    L or S) and that these are synchronized by means of a frequency comb with the very stable optical clock signals.
    According to an advantageous embodiment of the invention, it is possible to provide that LEO satellites (at an altitude of 400 to 1,500 km) and / or ground stations are equipped with navigation receivers for receive radio signals from MEO satellites.
    In addition, according to an advantageous embodiment of the invention, it is possible to provide that the LEO satellites are equipped with transmitters and that the MEO satellites are equipped with receivers for radio signals in order to perform pseudo measurements. bidirectional distance from MEO and / or LEO satellites.
    According to another advantageous embodiment of the invention, it is possible to provide that the MEO satellites are equipped with a terminal which can be directed to at least one of the LEO satellites and / or respectively to one of the ground stations .
    In an advantageous development of the invention, it is provided that at least one LEO satellite carries at least one
    According to an advantageous embodiment of the invention, it is possible to provide that the orbit times on the different orbits of the MEO satellites are synchronized using optical signals and / or radio waves through the LEO satellites and / or ground stations.
    In another suitable embodiment of the invention, it is possible to provide that, on LEO satellites and / or in ground stations, clocks are operated with very high long-term stability (in the meaning of a small Allan standard deviation) and that the time-synchronized constellation of MEO satellites be used for hourly distribution.
    It is also advantageous for the MEO satellites and / or LEO satellites and / or the ground stations to exchange measurements and / or other information by means of optical signals or radio waves.
    In another suitable embodiment of the invention, it is possible to provide that, on LEO satellites and / or ground control stations, e.g. ground stations estimate trajectories, signal offsets and possibly atmospheric parameters and distribute this information to the MEO satellites via optical signals and / or radio waves.
    According to another advantageous embodiment of variations in trajectories of LEO satellites which may be the invention, it is possible to provide that, 6, determined for example. by means of acceleration sensors can be used for the measurement of the earth's gravitational field.
    Furthermore, according to an advantageous embodiment of the invention, it is possible to provide that variations in the trajectories of LEO satellites can be determined, for example. by means of distance measurements between the MEO satellites of each orbit can be used for the measurement of the radiation pressure of the Sun.
    In an advantageous development of
    1'invention, it is expected that, as has already been suggested above, the clock of each MEO satellite has a laser, stabilized on cavity or respectively on resonator, with optical resonator.
    It is also advantageous for the MEO satellites to revolve around the Earth at an identical or substantially identical distance, the distance being in the range of 20,000 km to 25,000 km, and in particular 23,000 km, while it it is also possible to advantageously provide that the LEO satellites include several first LEO satellites evolving higher which revolve around the Earth at a first identical distance of, or essentially from, 1,000 km to 1,400 km, in particular 1 200 km, and several second LEO satellites evolving lower which revolve around the Earth at a second identical distance from 200 km to 600 km, in particular from 300 km or 400 km to 600 km.
    In another suitable embodiment of the invention, it is possible to provide that, for communication both with MEO satellites and with ground stations, LEO satellites have frequency transformers, in particular combs frequency, for converting optical signals from MEO satellites into radio signals for ground stations and vice versa.
    LEO satellites and in particular, if necessary, LEO satellites moving lower are suitable for the measurement of the Earth's gravitational field and for this purpose have laser clocks stabilized on cavity or respectively on resonator and / or inertial sensors.
    It is also advantageous that, due to extremely high time stability, at least briefly, according to the invention between the MEO satellites of a common orbit, the paths and speeds of MEO satellites and / or the solar pressure can be measured. with great precision. The influences of solar pressure mean that a satellite which, on its trajectory around the Earth, approaches the Sun evolves more slowly than when it moves away from the Sun. Due to the very stable signals from stabilized resonator lasers, these extremely small speed divergences can now be measured and used for the current determination of the position of MEO satellites.
    In another suitable embodiment of the invention, it is possible to provide that, for the adjustment of the orbit times of the MEO satellites adjusted by the LEO satellites, the ground stations can be used with a reference system or with the terrestrial time reference system taking into account a potential relative rotation of the earth and the set of MEO satellites.
    The satellite system according to the invention for navigation and geodesy advantageously uses the knowledge acquired in the context of the invention, according to which lasers stabilized on a resonator produce a signal much more stable than oscillating circuits stabilized on quartz , a much higher stability was reached with optical clocks (at least in the laboratory) than with current atomic clocks, optical signals allow a much better hourly and spatial resolution than radio signals, the frequency combs used as that frequency transformers are able to convert optical signals into radio signals and modern and compact inertial sensors allow the measurement of extremely small accelerations so that they can be used for the measurement of the Earth's gravitational field, at occasion where it was found that, for this, alongside the hor boxes provided according to the invention, it is possible in addition to using very precise inertial sensors as proposed by Professor Braxmaier from Bremen and Professor Ertmer from Hanover.
    The satellite system according to the invention can be used in all sectors of current satellite navigation and geodesy, however with a significantly higher precision than has been the case until now, and in particular also in as long as Precise Point Positioning (PPP) in real time.
    The drawing shows by way of example an embodiment of a structure of the satellite system according to the invention, only one of several, preferably three, uniformly inclined orbits, being shown here for the MEO satellites as well as for the satellites LEO. In addition, ground stations are suggested. The architecture of the system is roughly depicted in the drawing. The external MEO satellites contain cavity stabilized lasers. These are synchronized within an orbit by means of bidirectional optical links, and this by a time adjustment known per se. The interior LEO satellites establish the optical link between the MEO satellites of the different orbits and measure the navigation signals.
    The architecture therefore consists of a partial Medium Earth Orbit (MEO) constellation and optionally a partial Low Earth Orbit (LEO) constellation. The satellites are optically networked with each other. The links are used for synchronization, distance measurement and data transmission. The main differences with the state of the art are:
    the use of optical resonators in satellite navigation the optical time transfer between these satellites (telemetry has already been performed), in particular with the use of coherent phase measurements the extremely stable time which is calculated from there in the range in the short term on each orbit, the connection of the orbits by means of LEO satellites or respectively of the ground synchronization with optical clocks on LEO trajectories the measurement of signals from MEO satellites by receivers on LEO satellites.
    The system consists of MEO satellites in three orbits (similarly to Galileo or GLONASS) and a number of satellites flying below on the Low Earth Orbit. The free time base of the MEO satellites is produced by lasers in the optical range and stabilized on a cavity, which leads to very high short-term stability. The free time bases of the satellites are synchronized inside an orbit by bidirectional laser links. Due to the very high temporal resolution laser links, this synchronization is extremely good (resolution absolute measurement is in the range of 10 '12 seconds); the frequencies can be compared even more precisely (the vibrations of the satellite however have a limiting effect). The three orbits synchronized with great precision provide three times which can be adjusted to each other preferably optically and bidirectionally through one or more of the LEO satellites. This creates an extraordinarily rigidly synchronized time reference throughout the system. Bidirectional optical links are also used to measure distances and to estimate with great precision the solar pressure as well as the trajectories of the satellites. Finally, these links are used at the same time for data transmission.
    The stability of the optical time measurement system is transmitted to radio waves with a frequency comb. The frequencies of radio waves are currently mainly in the lower and middle L-band. With such wavelengths, the signals pass through the clouds without problem and can be processed in compact terrestrial receivers. However, the same signals are also received and processed by LEO satellites to determine satellite trajectories and instrumental offsets. This is done particularly well in so far as the signals do not pass through the atmosphere and are therefore not altered by it either. The total data exchange in this system can take place via bidirectional optical links and thus completely inside the system. On its own, that is to say without terrestrial infrastructure, the satellite system described so far provides the possibility of very precise positioning relative to an abstract reference system based on satellites. With a ground infrastructure, this reference system is adjusted with a terrestrial reference system. The main critical point here is a possible rotation between the two systems. Likewise, ground infrastructure can be used to measure atmospheric parameters and land tides. Soil measurement data can be sent back to the satellite system via appropriate radio links (now in the C-band) so there is no need to network the terrestrial infrastructure separately. In this case, it is sufficient in each position for a single C-band antenna which is directed towards a satellite, that is to say a LEO or MEO satellite, insofar as the data can be routed optically to the target satellites at inside the system via links between satellites (currently, several antennas are required on uplink stations).
    The satellites themselves carry at least three optical terminals. One is directed towards the preceding satellite in the same orbit. One is directed to the next satellite. And another is pointed down, toward LEO satellites or the Earth. The third terminal thus constitutes a link with LEO satellites. In another solution, it can also be directed to the
    Earth. It is used on the one hand for the synchronization of the trajectories and on the other hand for the determination of trajectories (MEO and LEO). The time base of the system described above is extremely stable for short periods of time, which is completely satisfactory for navigation. But the system can also be used to compare clocks that are very stable on the ground or to provide users with the time of clocks offering this high level of stability. It is also particularly interesting to use very stable clocks for LEO satellites and to produce universal time there. If these clocks have a stability of 10 "18 seconds, it is possible to use them to measure the Earth's gravitational field.
    LEO satellites evolve so low that they can be used perfectly for the measurement of the Earth's gravity field. With the exception of clocks, it is also possible to use very precise inertial sensors as they are produced by Professor Braxmaier from Bremen and Professor Ertmer from Hanover.
    Variants of the invention may further be described by the following features which can be described as embodiments of the invention carried out, summarized in the following groups and / or individually as individual features of the groups following.
    1.
    Geodesy satellite system, with
    - several satellites, at least two own clock, preferably for navigation and / or
    MEO respectively presenting which are arranged in a distributed manner in orbits and three,
    Earth, which revolve around the particular eight, MEO satellites being several, present in each orbit and / or
    - several LEO satellites and / or several ground stations and / or each optical satellite, namely communication
    MEO presenting two terminals a first optical terminal for free bi-directional beam optics by means of lasers with respectively the MEO satellite which precedes directly in the same orbit or with the two MEO satellites which precede directly in the same orbit, respectively, a second optical terminal for bidirectional free optical beam communication by means of lasers respectively with the MEO satellite which follows directly in the same orbit or with the two MEO satellites which follow directly in the same orbit, respectively, and possibly a third optical terminal which, for the communication of bidirectional free optical beam by means of lasers, is provided with one of the several LEO satellites and / or with one of the several ground stations and / or
    - the clocks of the MEO satellites which can be synchronized, orbit by orbit, by the communication of the optical free beam of these MEO satellites, and the MEO satellites of a common orbit respectively providing an orbit time by time adjustment according to the Composite principle Clock, and / or
    - LEO satellites and / or ground stations adjusting the orbit times.
    2. Satellite system according to group 1, characterized in that the clock of each MEO satellite has a laser stabilized on a cavity or on a resonator, with an optical resonator.
    3. Satellite system according to group 1 or 2, characterized in that the MEO satellites rotate around the Earth at an identical distance or at an essentially identical distance, the distance being in the range of 20,000 km to 25,000 km and in particular at 23,000 km.
    4. Satellite system according to one of groups 1 to 3, characterized in that the LEO satellites comprise several first LEO satellites evolving higher which revolve around the Earth at a first identical distance of or essentially from 1000 km to 1 400 km, in particular at 1,200 km, and several second LEO satellites evolving lower which revolve around the Earth at a second identical distance from 200 km to 600 km, in particular at 300 km or 400 km at 600 km.
    5. Satellite system according to one of groups 1 to 4, characterized by LEO satellites as well as by ground stations, LEO satellites presenting, for communication both with MEO satellites and with ground stations, frequency transformers, in particular frequency combs, intended for the conversion of optical signals from MEO satellites into radio signals for ground stations and vice versa.
    6. Satellite system according to one of groups 1 to 5, characterized in that the LEO satellites have laser clocks stabilized on a cavity or respectively on a resonator and / or inertial sensors for measuring the earth's gravitational field.
    7. Satellite system according to one of groups 1 to 6, characterized in that the two-way optical free beam communication between the satellites
    MEO of a common orbit can be used to measure the trajectory of MEO satellites and / or the solar pressure.
    8. Satellite system according to one of groups 1 to 7, characterized in that for the adjustment of the time 10 orbit of the adjusted MEO satellites through thesatellites LEO , the stations on the ground can to beused with a system of reference of timeearthly or respectively with the systemreference of terrestrial time in taking in has a 15 rotation relative potential of the Earth and
    the set of MEO satellites.
    权利要求:
    Claims (12)
    [1]
    1. Satellite system for navigation and / or geodesy, with several MEO satellites (at an altitude of 10 000 km to 30 000 km) presenting respectively their own clock which are arranged in a distributed manner in orbits and which revolve around the Earth, several MEO satellites, in particular eight, being present in each orbit, and several LEO satellites and / or several ground stations, each MEO satellite presenting two optical terminals for the bidirectional transmission of optical free beam signals by means of lasers with the respective first and / or second MEO satellite preceding (s) in the same orbit and with the respective first and / or second MEO satellite following / following in the same orbit and the clocks of the MEO satellites being, using optical free beam signals, synchronized orbit by orbit with each other to give a valid orbit time for this orbit.
    [2]
    2. Satellite system according to claim 1, characterized in that the clock of each MEO satellite has a laser stabilized on an optical cavity.
    [3]
    3. satellite system according to claim 1 or 2, characterized in that the MEO satellites transmit radio signals for navigation (for example in the L or S band) and these are synchronized by means of a frequency comb with very stable optical clock signals.
    [4]
    4. Satellite system according to one of the claims
    1 to 3, characterized in that LEO satellites (at an altitude of 400 to 1,500 km) and / or ground stations are equipped with navigation receivers to receive radio signals from MEO satellites.
    [5]
    5. Satellite system according to one of claims
    1 to 4, characterized in that the LEO satellites are equipped with transmitters and the MEO satellites with receivers for radio signals for carrying out bidirectional pseudo-distance measurements of the MEO satellites and / or LEO satellites.
    [6]
    6. Satellite system according to one of claims
    1 to 5, characterized in that the MEO satellites are equipped with a terminal which can be directed to at least one of the LEO satellites and / or one of the ground stations respectively.
    [7]
    7. Satellite system according to one of the claims
    1 to 6, characterized in that at least one LEO satellite carries at least one optical terminal.
    [8]
    8. Satellite system according to one of claims
    1 to 7, characterized in that the orbit times on the different orbits of the MEO satellites are synchronized using optical signals and / or radio waves through the LEO satellites and / or ground stations.
    • 19
    [9]
    9. Satellite system according to one of claims
    1 to 8, characterized in that clocks having a very high long-term stability (in the direction of a small Allan standard deviation) are implemented on LEO satellites and / or in ground stations and
    in that the constellation satellites MOE synchronized in time East used for the distribution schedule.
    [10]
    10. Satellite system according to one of claims
    1 to 9, characterized in that the MEO satellites and / or LEO satellites and / or ground stations exchange measurements and / or other information by means of
    signals optical or radio waves. 11. System of satellites according to one of the claims 1 to 10, characterized in that on of the satellites LEO and / or stations control at ground, eg. the stations on the ground estimate them traj ectoires, of the
    signal offsets and possibly atmospheric parameters and distribute this information to the MEO satellites by means of optical signals and / or radio waves.
    [11]
    12. Satellite system according to one of claims
    1 to 11, characterized in that variations in the trajectories of LEO satellites can be determined, for example. by means of acceleration sensors can be used for the measurement of the earth's gravitational field.
    [12]
    13. Satellite system according to one of claims
    1 to 12, characterized in that variations in • LE 0 trajectories of LEO satellites can be determined, for example. by means of distance measurements orbit by orbit between the respective MEO satellites can be used for the measurement of the radiation pressure of the Sun.
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    同族专利:
    公开号 | 公开日
    DE102017111091A1|2018-11-22|
    FR3066610B1|2020-02-28|
    DE102017111091B4|2019-01-10|
    WO2018215440A1|2018-11-29|
    CN110914708A|2020-03-24|
    EP3631514A1|2020-04-08|
    US20200209404A1|2020-07-02|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US5982323A|1997-05-24|1999-11-09|Oerlikon Contraves Ag|Satellite navigation system|
    CN101793526B|2010-04-12|2011-10-26|哈尔滨工业大学|Autonomous relative navigation method for multi-information fusion formation spacecrafts|
    US9379815B2|2014-08-26|2016-06-28|Raytheon Company|Electro-optical payload for high-bandwidth free space optical communications|CN112564770A|2020-12-01|2021-03-26|天地信息网络研究院有限公司|Multi-satellite co-location satellite communication system|
    CN112904705A|2021-01-22|2021-06-04|重庆邮电大学|Hierarchical clock synchronization method between low-orbit small satellites|
    法律状态:
    2019-04-17| PLFP| Fee payment|Year of fee payment: 2 |
    2019-08-23| PLSC| Search report ready|Effective date: 20190823 |
    2020-04-21| PLFP| Fee payment|Year of fee payment: 3 |
    2021-04-20| PLFP| Fee payment|Year of fee payment: 4 |
    优先权:
    申请号 | 申请日 | 专利标题
    DE102017111091.7A|DE102017111091B4|2017-05-22|2017-05-22|Satellite system for navigation and / or geodesy|
    DE102017111091.7|2017-05-22|
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