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WO2020260662A1 - Systèmes et procédés de détermination de paramètres d'orbite d'un satellite - Google Patents

Systèmes et procédés de détermination de paramètres d'orbite d'un satellite Download PDF

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Publication number
WO2020260662A1
WO2020260662A1 PCT/EP2020/068152 EP2020068152W WO2020260662A1 WO 2020260662 A1 WO2020260662 A1 WO 2020260662A1 EP 2020068152 W EP2020068152 W EP 2020068152W WO 2020260662 A1 WO2020260662 A1 WO 2020260662A1
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WIPO (PCT)
Prior art keywords
obtaining
signal
receivers
phase
tdoa
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PCT/EP2020/068152
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English (en)
Inventor
Roger MARTÍN FUSTER
German Ángel GRIMALDO SÁNCHEZ
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Asgard Space SL
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Asgard Space SL
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
    • B64G1/00—Cosmonautic vehicles
    • B64G1/22—Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
    • B64G1/24—Guiding or controlling apparatus, e.g. for attitude control
    • B64G1/242—Orbits and trajectories
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
    • B64G3/00—Observing or tracking cosmonautic vehicles
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
    • G01S5/0205—Details
    • G01S5/0221—Receivers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
    • G01S5/0294—Trajectory determination or predictive filtering, e.g. target tracking or Kalman filtering
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
    • G01S5/06—Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements

Definitions

  • the present disclosure relates to systems and methods for use in satellite orbit determination and/or satellite tracking.
  • the known methods for example, require the arrangement of ground sensors at very large distances from each other. Thus, the known techniques are inefficient and cumbersome to implement.
  • the invention comprises a method for determining at least two Time difference of arrival (TDOA) parameters suitable for determining an orbit of at least one target satellite having a transmitting frequency, the method comprising the steps of:
  • TDOA Time difference of arrival
  • RF Radio Frequency
  • the TDOA parameters obtained in this manner may be more precise than those obtained by known methods.
  • the method(s) according to the present invention use a cross-correlation determination that is partly based on interferometry.
  • Interferometry techniques may be very sensitive to positional changes or displacements (for example, a change in a satellite ' s orbit) of the elements in respect of which a position is to be determined.
  • interferometry can be highly vulnerable to relatively small phase errors.
  • aspects of the present invention such as synchronizing all elements with a master clock, using at least three receivers, and defining at least two pairs of receivers for determining a cross-correlation may help minimize such potential phase errors.
  • Using the present method it is possible to obtain precise data on the orbit of a target satellite by obtaining the two potential TDOA values corresponding to the target satellite. In this manner, the present system can be made more compact than known systems.
  • the present system(s) and method(s) provide a precision in the TDOA parameter determination that, if using known methods, would require a distance between receiving antennas in the order of hundreds of kilometers.
  • the present invention enables the placement or arrangement of the receiving antennas at separation distances, for example, in the order of tens of meters, to attain the same precision in the TDOA parameter(s).
  • satellites are assigned a specific frequency band for signal transmission and reception.
  • the methods according to the present invention can be performed in parallel for all the satellites, by selecting the transmitting frequencies corresponding to each satellite, without having to change (for example, increase) the number of antennas used.
  • the number of elements the system uses for obtaining the TDOAs of multiple satellites can be reduced or minimized, without introducing phase errors (which can negatively affect the cross-correlation calculations).
  • the methods and systems according to the present invention are more versatile, given that the type of data input to the system (the signals or portions thereof picked up by the receivers) can encompass a greater variety, and need not have to be necessarily obtained in an active manner (that is, under command from the system to the satellite), but may also be of exclusively passive origin.
  • any type of signal emitted by the satellite(s) during its functioning may be used.
  • a content signal or a telemetry beacon may be used to carry out the invention, as long as the satellite transmitting frequency is known.
  • a radar-type scheme may be employed (sending a signal to the at least one satellite, wherein the receiving antennas receive the rebound signal) such that the method(s) and system(s) according to the present invention may obtain reliable TDOAs and the satellite orbit may thus be obtained in a reliable manner.
  • determining a cross-correlation parameter between the obtained baseband In-phase and Quadrature signals corresponding to each receiver within the defined pair of receivers comprises:
  • obtaining said at least one TDOA parameter comprises obtaining said at least one TDOA parameter at least partly based on said phase angle value.
  • obtaining said at least one TDOA parameter comprises performing a selective calculation comprising the steps of:
  • the received RF signal is an analog signal
  • the method(s) may further comprise the step of:
  • a complex Cross-Correlation parameter comprises determining a Cross Ambiguity Function, and the method further comprises the steps of:
  • FDOA Frequency difference of arrival
  • the transmitting frequency of the at least one target satellite is obtained by means of a signal synchronization module, using the master clock signal as a reference signal.
  • a signal synchronization module for obtaining the transmitting frequency of each target satellite is provided for each of the at least three receivers, using the master clock signal as a reference signal.
  • the signal synchronization module comprises a phase-locked loop circuit.
  • the step of obtaining In-phase and Quadrature signals from the received RF signal comprises the steps of:
  • the obtained In-Phase signals may comprise baseband In-Phase signals.
  • the step of obtaining an RF signal corresponding to the at least one portion of the transmitted signal of each target satellite further comprises the step of converting the received analog signal into an optical signal, via, for example analog optical transceivers.
  • the RF signal from each receiver is transported from its receiving point to a common processing point.
  • Such signal transportation must be performed in a manner which requires, amongst other factors, no previous demodulation or time-discretization of the signal in any form. Otherwise the main purpose of coherency and synchronization would be defeated. Therefore, a digital optical link, typically used for fast data communications, cannot be applied for this matter.
  • the only way to use an optical link while keeping the coherency shall be using a non-distorting low noise analog electro-optical modulation process and its complementary electro-optical demodulation. Such process is not an industry standard application and requires much higher performance and constraints than a digital optical link.
  • the amplified analog signal(s) are converted directly to optical signal(s) without any prior digitization.
  • the at least three receivers comprise antennas configured for receiving signals in the radiofrequency spectrum.
  • the antennas may be configured, for example, to receive signals in the K, Ku, C, L and/or S RF bands.
  • the method(s) according to the invention further comprises the step of associating the at least one TDOA parameter with a time stamp or ' epoch ' .
  • a time stamp or epoch may be provided by a GPS receptor which provides precise UTC standard time.
  • a system for determining at least two Time Difference of arrival (TDAO) parameters suitable for determining an orbit of at least one target satellite having a transmitting frequency is also provided.
  • the system may comprise at least three receivers for obtaining a radiofrequency signal based on at least one portion of a signal transmitted by at least one target satellite;
  • processing means are configured to
  • performing the selective calculation by the processor of the system may comprise the steps of:
  • the three receivers comprise antennas configured for receiving signals in the radiofrequency spectrum.
  • the antennas may be configured for receiving signals in the K, Ku, C, L or S RF bands.
  • the receivers may be configured to receive signals in other frequency bands.
  • the obtained In-Phase signals comprise baseband In-Phase signals.
  • system processing means comprise at least one field- programmable gate array (FPGA).
  • FPGA field- programmable gate array
  • the processing means comprise one or more of a central processing unit (CPU), a graphical processing unit (GPU), a configurable processor, a FPGA, and a microprocessor.
  • the system may further comprise means for obtaining an optical signal from the at least one portion of the signal transmitted by the at least one target satellite, and means for obtaining an RF signal from said optical signal.
  • the means for obtaining an optical signal from the at least one portion of the signal transmitted by the at least one target satellite comprise a fiber optic medium.
  • a method for determining at least two Time difference of arrival (TDOA) parameters suitable for determining an orbit of at least one target satellite having a transmitting frequency, the method comprising the steps of processor configured for:
  • Determining a cross-correlation parameter between the obtained baseband In-phase and Quadrature signals corresponding to each receiver within the defined pair of receivers comprises:
  • obtaining said at least one TDOA parameter comprises obtaining said at least one TDOA parameter at least partly based on said phase angle value.
  • Obtaining said at least one TDOA parameter comprises performing a selective calculation comprising the steps of: -Obtaining a natural number N of iterations to be performed by the selective calculation;
  • At least one processor is provided which is configured with instructions to carry out one or more method(s) according to the invention.
  • the at least one processor may comprise one or more of a FPGA, microprocessor, central processing unit (CPU), and Graphical Processing Unit (GPU).
  • a method is provided. The method may comprise determining at least two Time difference of arrival (TDOA) parameters, suitable for determining an orbit of at least one objective satellite, the satellite transmitting a signal at a corresponding transmitting frequency, the transmitted signal being received by at least three receiving antennas, the method comprising the steps of:
  • TDOA Time difference of arrival
  • RF Radio Frequency
  • Obtaining a parameter may comprise,
  • Adding a number of cycles P refers to adding a phase value (e.g. in terms of multiples of pi in radian units).
  • a cross-correlation may comprise a correlation calculation applied for a given frequency of the signals.
  • TDOA is obtained from the phase of the complex number that results of applying Cross Correlation to its input signals. It provides information of the position of the satellite over time.
  • a Cross Ambiguity function may be used; which is a correlation calculation that may be applied to a plurality of frequencies of the signals.
  • FDOA is obtained from the magnitude of the complex number that results of applying Cross Correlation to its input signals. It provides information about the speed of the satellite over time.
  • Obtaining the number N of iterations to be performed can be achieved in any suitable manner, depending on different criteria. For example, a higher number N of iterations may be selected when accuracy is highly critical, while a lower number of iterations N may be selected when speed or efficiency are critical.
  • a master clock is obtained, which may be used by a system performing a method according to the present invention.
  • the master clock may be obtained by employing a local oscillator at a substantially stable frequency.
  • a local oscillator may comprise, for example, a crystal oscillator, which delivers a substantially reliable clock signal.
  • the local oscillator may be substantially isolated from any exterior signal, and may not require any external signal to be obtained.
  • the master clock may synchronize a plurality of elements that may perform steps of the present method(s), achieving a synchronized performance of the method(s), which advantageously minimizes the introduction of time-, frequency- or phase- related errors in the processing of the signal(s).
  • target satellite refers to a satellite for which a parameter(s) is/are being determined in accordance with one or more aspects of the invention.
  • Each target satellite may transmit a signal to the receivers.
  • This signal may be a signal transmitted actively by the satellite in a substantially autonomous way, or actively in response to a signal sent to the satellite. It may also be a signal sent to the satellite by any other device or system, including the system performing the method of the present invention, which bounces back from the satellite and is received by the receivers (e.g. antennas (as in the case of a radar system)).
  • the signal is transmitted by the target satellite and received by the receivers in a given or particular transmitting frequency (normally defined by a transmitting frequency band), which is known (or made known) to the system performing the method(s) according to the present invention.
  • a transmitting frequency band normally defined by a transmitting frequency band
  • the satellite may have a predetermined working frequency band in which it is allowed to send data (normally assigned by
  • a signal may have been sent to the satellite and backscattered, the sent signal having a frequency that is known by the present system(s).
  • a synchronizing element for each receiver.
  • a synchronizing element may comprise a Phase-Locked Loop (PLL) circuits (or other similar circuits which achieve substantially the same result), which synthesize each transmitting frequency using the master clock as a reference signal.
  • PLL Phase-Locked Loop
  • a different PLL circuit may be used to obtain each transmitting frequency. This way, by having or providing a specific PLL circuit per frequency, the system avoids introducing aleatory phases to the transmitting frequencies (which may be introduced by a PLL circuit when it is activated in the case of using a plurality of PLL circuits to obtain one transmitting frequency).
  • a definition of at least two (different) pairs of receivers (or antennas) is performed. This definition is performed for all the receivers (or antennas) the system may comprise or may have access to. For example, if a given system performing the present method uses three receivers (or antennas), at least two different pairs of receivers (or antennas) from among said three receivers (antennas) in any possible combination. Another possibility could be that a first pair comprises the first and the second antenna, and a second pair comprises the second and the third antenna.
  • At least three different pairs of receivers are defined in respect to the at least three (different) receivers.
  • a first pair may comprise the first and second receiver
  • a second pair could comprise the first and the third receiver
  • a third receiver pair may comprise the second receiver and the third receiver.
  • the at least two TDOA parameters may thus be obtained taking into account all pair permutations (three pairs) for the three receivers. This would yield a total of six TDOA parameters.
  • the system performing the method(s) of the present invention comprises four antennas.
  • the defined pairs could be any possible combination between said four antennas, as long as at least two pairs (two pairs or more) are defined.
  • a first pair may comprise a first and second antenna
  • a second pair may comprise a first and a fourth antenna
  • a first pair comprises a first and second antenna
  • a second pair comprises a third and a fourth antenna
  • each obtained received signal which may be a Radio Frequency (RF) signal
  • RF Radio Frequency
  • l/Q baseband In-phase and Quadrature signal
  • This demodulation may be performed in one step, or alternatively may be performed in at least two steps, by demodulating the obtained received signal, which is an RF signal, into an Intermediate Frequency (IF) signal, and further lowering the signal from an IF signal to a band base in-phase quadrature signal.
  • IF Intermediate Frequency
  • a complex correlating parameter is obtained by performing a Cross Correlation in between the obtained base band in- phase and quadrature signals corresponding to each antenna within the defined pair of receiving antennas.
  • a Cross Correlation is applied between the base band in-phase and quadrature signal of the first antenna and the base band in-phase and quadrature signals of the second antenna.
  • the Cross Correlation performed in between the two signals is a well-known calculation, widely applied in signal processing, which measures the similarity in between said two signals, and it gives as a result a correlating parameter which is a complex number, and which can be represented in polar form as an amplitude parameter and a phase parameter.
  • the obtained phase of said obtained complex correlating parameter is used in the following steps.
  • This phase can be used to obtain a TDOA which is considered to be ambiguous, because it only partially delivers information useful for the obtaining of the orbit of a satellite. Since it is a phase, the value of this parameter ranges from values [-TT, +TT], but without knowing a number of cycles corresponding to the phase parameter, the TDOA extracted from said phase may define an infinite number of potential satellite orbits.
  • the system needs to find an approximation of a TDOA from the obtained phase by obtaining a number of cycles which has to be added to the obtained phase, in order to obtain a single TDOA.
  • the system performing the method of the present invention performs an iteration of an Orbital Determination Algorithm, each algorithm resulting in a possible TDOA (from which a possible orbit of the satellite is easily obtained) and a remainder parameter. From all the iterations, the best output is defined to be used to obtain a single TDOA.
  • Orbital Determination Algorithms used in the state of the art, and the present method can use any of the ones which deliver as a result a possible orbit of the satellite and try to minimize the remainder parameter while doing so, the remainder parameter giving information about how close to reality or reliable the resulting orbit (easily obtained from the obtained possible TDOA) calculated by the algorithm is.
  • a natural number N is defined in order to perform N iterations of possible solutions of the algorithm, thus obtaining at least 2N TDOAs, at least 2P plausible number of cycles and at least 2N Orbit Determination remainders.
  • the definition of P may be based on many different factors, but a good starting point to know the magnitude of P may be the magnitude of the complex correlating parameter.
  • a TDOA can be extracted directly from said magnitude, but its reliability is very low, thus it is a good starting point to define a possible P number.
  • Other information can be used to in addition to the magnitude of the complex correlating parameter, or on its own, related to a rough estimate of the position of the satellite in the sky related to the position of the antennas. That is, a possible range of orbits can be deduced by the fact that the satellite may be of a certain type (geo-stationary, of a certain group of known orbits, etc...) which provides another good starting point to determine a possible definition of P.
  • P refers to the natural number of cycles to be added to the obtained phase of the complex correlating parameter in order to obtain a reliable TDOA.
  • the cycles are in phase units (for example, degrees or radians), and in each of the N iterations, the calculation can be made directly with the phase value.
  • the phase value may be converted to a TDOA value prior to the calculation.
  • the selective calculation may comprise the following:
  • phase units for example, degrees or radians. And in each iteration the number of cycles is added to the phase in the prescribed phase unit (e.g., degrees or radians).
  • the output of each iteration represents a potential orbit with an associated remainder value.
  • the number of cycles P which has resulted in the orbit with the lowest remainder or residual value in (absolute) mathematical terms).
  • a TDOA parameter for each defined pair of receiving antennas is obtained by adding the lowest remainder parameter P (number of cycles P) obtained in the iteration (among N possible obtained remainder parameters) to a TDOA obtained from the phase angle of the obtained complex correlating parameter.
  • the invention is also directed to computer program product comprising program instructions for causing a computing system to perform any one or more of the methods disclosed herein.
  • the invention is also directed to a computer program product as indicated above, embodied on a storage medium.
  • the invention is also directed to a computer program product as indicated above, carried on a carrier signal.
  • Figure 1 is a block diagram of a system according to an exemplary embodiment of the invention.
  • Figure 2 is a block diagram of a digital converter system according to an exemplary embodiment of the invention.
  • Figure 3 is a schematic depiction of a synchronization module according to an exemplary embodiment of the invention.
  • Figure 1 illustrates an example of the system for determining an orbit path according to the present invention, in a block diagram form.
  • the system is connected to a plurality of antennas, in this case three antennas (A1), (A2) and (A3), which receive signals from two objective satellites S1 and S2 (not shown).
  • Each antenna receives said signals and adapts them by means of an Antenna feed system (101), a Low Noise Amplifier (102) which amplifies the signal without demodulating it, and an optical transmitter to convert the amplified electrical signal into an optical signal which is sent through an Optical Transmitting system (200), connected through an optic fiber cable to an Optical Receiver System (RF Front end) (300).
  • FIG. 2 shows a detailed block diagram of the Optical Receiver System (RF Front end) (300), wherein the optical signal is received, which converts the light signal into an electrical signal through its photodetector (301).
  • the converted electrical signal which is an RF (radio frequency) signal, is further lowered or demodulated to IF (intermediate frequency) by means of a mixer (302), using an RF clock (302CK) signal. No digital signal.
  • the demodulated signal is further sent into two In-phase and Quadrature mixers (303A) (303B) (hereinafter called l/Q mixers), one for each of the objective satellites.
  • These mixers (303A) (303B) demodulate the same signal into In-phase and Quadrature components, demodulating the signal from one satellite each (Satellites S1 and S2). This is achieved by using an IF clock for each signal corresponding to each satellite S1 and S2, i.e., for obtaining the signal of the first satellite S1 , a first IF clock (303A_CK) is used, and for obtaining the signal of the second satellite S2, a second IF clock (303B_CK) is used.
  • These clocks may be previously known, since they are related to the transmitting frequency designated or allocated to each satellite. Both the ADC clock and the IF clock are generated using the Master Clock and PLLs.
  • the output of l/Q mixer (303A) is a group of two signals (303A_S1), the two signals being an In-phase component and a Quadrature component corresponding to satellite S1.
  • the second l/Q mixer (303B) whose output is a group of two signals (303B_S2), the two signals being an In-phase and a Quadrature component corresponding to satellite S2.
  • both (303A_S1) and (303B_S2) are converted into digital signals by means of an Analog-Digital Converter (304) (hereinafter called ADC), using a clock signal (304CK).
  • ADC Analog-Digital Converter
  • the output of the ADC (304) comprises the digitalized versions of (303A_S1) and (303B_S2), and is connected then to the input lines of a Processing means (400), in this case a FPGA (Field Programmable Gate Array) which will be executed in real time.
  • a Processing means in this case a FPGA (Field Programmable Gate Array) which will be executed in real time.
  • the other two Antennas (A2) and (A3) are connected to an analogous chain of circuits, which use as their corresponding Clock signals (302CK), (303A_S1), (303B_S2) and (304CK), obtaining the same signals as in the case of the first Antenna (A1), but with the input signal of corresponding Antennas (A2) and (A3).
  • the use of the same clock signals ensures that the overall system of the present invention (each part of the system corresponding to each Antenna) is completely synchronized and minimal (if any) time/frequency differences are introduced in the overall system as might be by the use of different clocks.
  • Each digitalized output from each ADC corresponding to each Antenna is connected to the input of the FPGA (400), which may compute, for example, in real time, a Cross Correlation value.
  • the process of this function may comprise the following:
  • the selective calculation may comprise the following:
  • phase units for example, degrees or radians. And in each iteration the number of cycles is added to the phase in the prescribed phase unit (e.g., degrees or radians).
  • the number of cycles is represented in time units (for example, seconds), and in each iteration the conversion of the number of cycles to TDOA domain is added to the existing TDOA.
  • the output of each iteration represents a potential orbit with an associated remainder value.
  • the number of cycles P which has resulted in the orbit with the lowest remainder or residual value in (absolute) mathematical terms).
  • a TDOA parameter for each defined pair of receiving antennas is obtained by adding the lowest remainder parameter P(number of cycles P which resulted in the lowest remainder during the iteration, among N possible obtained remainder parameters) to a TDOA obtained from the phase angle value of the obtained complex correlating parameter.
  • the result of said iteration outputs as a result a digital data matrix of complex numbers which is sent by the FPGA to a CPU for further processing of the data.
  • Figure 3 illustrates a synchronizing module comprised within the system of the present invention, wherein all the clocks needed in the part of the system shown in Fig1 are generated.
  • the synchronizing module is used to ensure the synchronization of all the parts of system, through their corresponding clocks. Therefore, all the clocks used in it are generated from a master clock. More specifically, the synchronizing module comprises a local oscillator (hereinafter called LO) (500) used as a Master clock, whose output is connected to a plurality of interfaces, which adapt the signal to be compatible with the specifications of each clock, but introducing no variable time delay within any of the resultant clocks, which is important to avoid any
  • LO local oscillator
  • the output of the LO (500) is connected to a first interface 501 to generate a clock signal for the processor (for example, an FPGA).
  • the output of the LO (500) is also connected to a second interface 502 to generate various clock signals for the analog- to-digital converters, and to a third interface 503 to generate clock signals for the various mixers.
  • the methods and systems disclosed herein are not limited to satellite detection and tracking, but may also be employed, for example, for detecting and/or tracking other objects in spatial orbit such as spatial debris, space shuttles, etc.
  • obtaining said at least two TDOA parameters comprises obtaining said at least two TDOA parameters at least partly based on said phase angle value.
  • FDOA Frequency difference of arrival
  • Clause 6 Method according to any of the preceding clauses, wherein the transmitting frequency of the at least one target satellite is obtained by means of a signal synchronization module, using the master clock signal as a reference signal.
  • Clause 7 Method according to any of the preceding clauses, wherein a signal synchronization module for obtaining the transmitting frequency of each target satellite is provided for each of the at least three receivers, using the master clock signal as a reference signal.
  • Clause 8 Method according to Clause 6 or Clause 7, wherein the signal synchronization module comprises a phase-locked loop circuit.
  • step of obtaining a baseband In-phase and Quadrature signal from the received RF signal comprises the steps of:
  • step of obtaining an RF signal corresponding to the at least one portion of the transmitted signal of each target satellite further comprises the step of converting the received analog signal into an optical signal.
  • Clause 1 Method for determining at least two Time difference of arrival (TDOA) parameters suitable for determining an orbit of at least one target satellite having a transmitting frequency, the method comprising the steps of processor configured for: -receiving at least three digital representations of an In-Phase and Quadrature signals corresponding to at least three different receivers,
  • TDOA Time difference of arrival
  • obtaining said at least one TDOA parameter comprises obtaining said at least one TDOA parameter at least partly based on said phase angle value.
  • Method of Clause 12, wherein obtaining said at least one TDOA parameter comprises performing a selective calculation comprising the steps of:
  • At least three receivers for obtaining a radiofrequency signal based on at least one portion of a signal transmitted by at least one target satellite
  • processing means are configured to
  • Clause 15 The system of Clause 14, wherein performing the selective calculation comprise the steps of: • Obtaining a natural number N of iterations to be performed by the selective calculation;
  • Clause 16 System of Clause 14 or Clause 15, wherein the at least three receivers comprise antennas configured for receiving signals in the radiofrequency spectrum.
  • Clause 17 System of any of clauses 13-16, further comprising means for obtaining an optical signal from the at least one portion of the signal transmitted by the at least one target satellite, and means for obtaining an RF signal from said optical signal.
  • Clause 18 System of Clause 17, wherein the means for obtaining an optical signal from the at least one portion of the signal transmitted by the at least one target satellite comprise a fiber optic medium.
  • Clause 19 System according to the system of any of clauses 13-18, wherein the antennas are configured for receiving signals in K, Ku, C, L and/or S RF bands.
  • Clause 21 System according to any of Clauses 13-20, wherein the processing means comprise at least one field-programmable gate array (FPGA).
  • FPGA field-programmable gate array
  • Clause 22 System according to any of Clauses 13-21 , wherein the processing means comprise one or more of a central processing unit (CPU), a graphical processing unit (GPU), a configurable processor, a FPGA, and a microprocessor.
  • CPU central processing unit
  • GPU graphical processing unit
  • FPGA field-programmable gate array
  • microprocessor microprocessor
  • Clause 23 Method according to any of the clauses 1-13, wherein the at least three receivers comprise antennas configured for receiving signals in the radiofrequency spectrum.
  • Clause 24 Method according to any of the clauses 1-13 and 23, further comprising the step of associating the at least one TDOA parameter with a time stamp/epoch.
  • Clause 25 Processor configured with instructions to carry out one or more of the methods according to clauses 1-13 and 23-24.
  • Clause 26 Processor according to Clause 25, wherein the processor comprises one or more of a FPGA, microprocessor, central processing unit (CPU), and Graphical Processing Unit.
  • the processor comprises one or more of a FPGA, microprocessor, central processing unit (CPU), and Graphical Processing Unit.
  • Clause 27 A computer program product comprising program instructions for causing a computing system to perform any one or more of the methods of claims 1-13 and 23- 24.
  • Clause 28 The computer program product of Clause 27, embodied on a storage medium.
  • Clause 29 The computer program product of Clause 27, carried on a carrier signal.
  • Clause 30 The method of Cause 1 , wherein the step of obtaining an RF signal corresponding to the at least one portion of the transmitted signal of each target satellite, further comprises the step of converting the received analog signal into an optical signal without any prior digitization of the received analog signal.
  • Clause 31 The method of Clause 30, wherein the step of obtaining an RF signal corresponding to the at least one portion of the transmitted signal of each target satellite, further comprises the step of amplifying the received analog signal prior to converting the analog signal into an optical signal.
  • Clause 32 The system of Clause 14, wherein the at least three receivers for obtaining a radiofrequency signal based on at least one portion of a signal transmitted by at least one target satellite comprise an optical transmitter for converting the at least one portion of a signal transmitted by at least one target satellite to an optical signal.
  • Clause 33 The system of Clause 32, wherein the at least three receivers for obtaining a radiofrequency signal based on at least one portion of a signal transmitted by at least one target satellite further comprise a low noise amplifier for amplifying the at least one portion of a signal transmitted by at least one target satellite prior to converting the analog signal to an optical signal.
  • Clause 34 The system of Clause 14, wherein the at least three receivers for obtaining a radiofrequency signal based on at least one portion of a signal transmitted by at least one target satellite comprise a low noise amplifier for amplifying the at least one portion of a signal transmitted by at least one target satellite, and an optical transmitter for converting the amplified at least one portion of a signal transmitted by at least one target satellite to an optical signal.
  • the at least three receivers for obtaining a radiofrequency signal based on at least one portion of a signal transmitted by at least one target satellite comprise a low noise amplifier for amplifying the at least one portion of a signal transmitted by at least one target satellite, and an optical transmitter for converting the amplified at least one portion of a signal transmitted by at least one target satellite to an optical signal.

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  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Astronomy & Astrophysics (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)

Abstract

L'invention concerne des systèmes et des procédés pour déterminer des paramètres appropriés pour déterminer une orbite d'un satellite à l'aide de paramètres TDOA et de plusieurs récepteurs espacés.
PCT/EP2020/068152 2019-06-28 2020-06-26 Systèmes et procédés de détermination de paramètres d'orbite d'un satellite Ceased WO2020260662A1 (fr)

Applications Claiming Priority (2)

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EP19382556 2019-06-28
EP19382556.9 2019-06-28

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WO2020260662A1 true WO2020260662A1 (fr) 2020-12-30

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2148214A2 (fr) * 2008-07-24 2010-01-27 SES Astra S.A. Système et procédé d'évaluation de position d'engin spatial
EP2972455A2 (fr) * 2013-03-15 2016-01-20 Raytheon Company Différence entre les fréquences d'arrivée (fdoa) pour la géolocalisation
ES2692175A1 (es) * 2017-05-31 2018-11-30 Universitat Politécnica de Catalunya Sistema y procedimiento para la determinación de órbitas de satélites

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2148214A2 (fr) * 2008-07-24 2010-01-27 SES Astra S.A. Système et procédé d'évaluation de position d'engin spatial
EP2972455A2 (fr) * 2013-03-15 2016-01-20 Raytheon Company Différence entre les fréquences d'arrivée (fdoa) pour la géolocalisation
ES2692175A1 (es) * 2017-05-31 2018-11-30 Universitat Politécnica de Catalunya Sistema y procedimiento para la determinación de órbitas de satélites

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HERRERA L E YNOQUIO ET AL: "Linearization techniques for electro-optical modulation in analog radio over fiber", 2017 SBMO/IEEE MTT-S INTERNATIONAL MICROWAVE AND OPTOELECTRONICS CONFERENCE (IMOC), IEEE, 27 August 2017 (2017-08-27), pages 1 - 4, XP033270472, DOI: 10.1109/IMOC.2017.8121049 *

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