System and method for calibrating ground stations

Abstract

A geosynchronous equatorial orbit (GEO) ground station may simultaneously receive both a first signal (downlink data) at a first frequency and an internally generated calibration signal at a second frequency at a tracking receiver. Based on the calibration signal, the tracking receiver may determine a first phase value at the second frequency, and then, from the first phase value, determine a second phase value associated with the first frequency based on a first phase offset between the first and second frequencies according to a receiver calibration coefficient set, and then generate a phase correction value for the received signal at the first frequency without interrupting the downlink data coming from the GEO satellite. Having an accurate phase enables the tracking receiver to accurately report tracking errors to an antenna controller, thus enabling improved tracking performance.

Description

[Technical Field]

[0001] cross reference This patent application claims the interests of U.S. Provisional Patent Application No. 63 / 092,884, filed on 16 October 2020, entitled "SYSTEMS AND METHODS FOR CALIBRATING GEO GROUND STATIONS," which has been assigned to the applicant of this document and is expressly incorporated herein by reference in its entirety. [Background technology]

[0002] The following generally pertains to communications, including systems and methods for calibrating ground stations (e.g., geosynchronous equatorial orbit (GEO) ground stations). Ground stations may communicate with satellites according to specific communication frequencies (e.g., radio frequency (RF) carrier frequencies). Ground stations may perform frequency tracking for downlink and uplink communications with satellites. Some satellite tracking systems may use labor-intensive phase matching processes across multiple RF paths. RF cables in RF paths may be trimmed to length, and manual phase shifters may be adjusted in the field. Furthermore, amplifiers used in RF paths may be adapted to a reference. Temperature changes can alter the phase of amplifiers, and the phase shift introduced by amplifiers may also shift over time. In addition, long and expensive RF cables may be extended alongside antennas to provide tracking signals. Cables may be damaged in the field. Therefore, tracking techniques at communication frequencies may be used to eliminate the requirements of phase-matched components, manual phase shifters / adjustments, or labor-intensive RF cable trimming. However, while such techniques may need to be performed periodically, they require the temporary suspension or interruption of communications on the communication frequency in order to carry out tracking. [Overview of the Initiative]

[0003] The techniques described relate to improved methods, systems, devices, and apparatus for supporting satellite operation. A ground station (e.g., a geosynchronous equatorial orbit (GEO) ground station) may implement a tracking system including a tracking receiver. The tracking receiver may simultaneously receive both a first signal at a first frequency and a calibration signal at a second frequency, as well as a calibration signal at a second frequency, via a first and a second path. The first signal may be a communication signal received via the ground station's antenna. The calibration signal is output by the tracking receiver and is coupled with the first and second paths. Based on the calibration signal, the tracking receiver may determine a first phase value for the second frequency. Then, from the first phase value, the tracking receiver may determine a second phase value associated with the first frequency based on a first phase offset between the first and second frequencies, based on a receiver calibration coefficient set, and then generate a phase-corrected value for the received signal at the first frequency. Phase differences may also exist due to different path lengths between a first receiver of a tracking receiver configured to receive communication signals and a second receiver of the tracking receiver configured to receive calibration signals. During calibration, the tracking receiver may calibrate these differences based on phase offsets identified by a set of receiver calibration coefficients. By performing calibration at a second frequency different from the frequency used for communication signals, the tracking receiver can perform calibration for tracking without interrupting the communication signals, thereby providing more accurate tracking error signals and improving overall system tracking. In some embodiments, having accurate phases enables the tracking receiver to accurately report tracking errors to the antenna controller, thus enabling improved tracking performance.

[0004] During the characterization phase of the tracking system, for example, during or immediately after the installation or deployment of a ground station, the tracking receiver may generate a set of receiver calibration coefficients using different frequency sets. The tracking receiver may output calibration signals across each frequency in the frequency set and determine the phase of each frequency. The tracking receiver performs calibration of each receiver in the tracking receiver, for example, to account for differences between receivers in the tracking receiver. Values ​​representing different calibration coefficients in the receiver calibration coefficient set may be represented and stored in the tracking receiver. Characterization of the tracking system may allow the phase of the communication signal to be determined using calibration signals of different frequencies. [Brief explanation of the drawing]

[0005] [Figure 1] Figure 1 shows an example of a satellite communications system that supports a system and method for calibrating a ground station according to the embodiments described herein. [Figure 2] Figure 2 shows another example of a satellite communications system supporting a system and method for calibrating a ground station according to the embodiments described herein. [Figure 3] Figure 3 shows an example of a tracking system that supports a system and method for calibrating a ground station according to the embodiments described herein. [Figure 4] Figure 4 shows an example of a tracking system that supports a system and method for calibrating a ground station according to the embodiments described herein. [Figure 5] Figure 5A shows an example of a tracking receiver supporting a system and method for calibrating a ground station according to an embodiment described herein. Figure 5B shows an example of an antenna system supporting a system and method for calibrating a ground station according to an embodiment described herein. Figure 5C shows an example of an antenna system supporting a system and method for calibrating a ground station according to an embodiment described herein. [Figure 6] Figure 6 shows an example of a ground station supporting a system and method for calibrating a ground station according to the embodiments described herein. [Figure 7]Figure 7 shows a flowchart illustrating one or more methods supporting a system and method for calibrating a ground station according to the embodiments described herein. [Figure 8] Figure 8 shows a flowchart illustrating one or more methods supporting a system and method for calibrating a ground station according to the embodiments described herein. [Modes for carrying out the invention]

[0006] A ground station may implement a tracking system including a tracking receiver. In some embodiments, the ground station may be a geosynchronous equatorial orbit (GEO) ground station. The tracking system may require calibration of the phase difference in the antenna's signal path to a ground station transceiver, including a tracking transceiver. Initial phase calibration may be performed in connection with the installation and setup of the tracking system at a specific temperature. However, temperature changes and shifts caused over time may affect the phase of different signal paths and between the signal path and the calibration path. Certain techniques may allow periodic or intermittent calibration procedures, but such procedures may interrupt the reception of the communication signal and degrade throughput and overall communication performance. Systems and methods for tracking a calibration signal at a frequency different from the frequency of the communication signal may allow for uninterrupted reception of the communication signal. Characterization procedures may be performed during or immediately after installation to determine receiver calibration coefficients that can be used to determine the phase at the communication frequency from the phase determined at the calibration frequency.

[0007] A tracking receiver may simultaneously receive both a first signal at a first frequency and a calibration signal at a second frequency via a first and a second path. The first signal may be a communication signal received via a ground station antenna. The calibration signal may be output by the tracking receiver and coupled with the first and second paths. Based on the calibration signal, the tracking receiver may determine a first phase value for the second frequency. Then, from the first phase value, the tracking receiver may determine a second phase value associated with the first frequency based on a first phase offset between the first and second frequencies, based on a receiver calibration coefficient set, and then generate a phase correction value for the received signal at the first frequency. The phase difference may also exist due to a difference between a first receiver of the tracking receiver configured to receive the communication signal and a second receiver of the tracking receiver configured to receive the calibration signal. During calibration, the tracking receiver may calibrate these differences based on the phase offset identified by the receiver calibration coefficient set. By performing calibration at a second frequency different from the frequency used for the communication signal, the tracking receiver can perform calibration for tracking without interrupting the communication signal, thereby improving throughput.

[0008] During the characterization phase of the tracking system, for example, during or immediately after the installation or deployment of a ground station, the tracking receiver may generate a set of receiver calibration coefficients using different frequency sets. The tracking receiver may output calibration signals across each frequency in the frequency set and determine the phase of each frequency. The tracking receiver performs calibration of each receiver in the tracking receiver, for example, to account for differences between receivers in the tracking receiver. Values ​​representing different calibration coefficients in the set of receiver calibration coefficients may be represented and stored in the tracking receiver. For example, values ​​representing different calibration coefficients may be gradient and offset parameters for linear optimal fitting of position-relative frequency data acquired during the characterization phase, and may be represented or otherwise. Characterization of the tracking system may allow the phase of the communication signal to be determined using calibration signals of different frequencies.

[0009] The features of this disclosure are first described in the context of satellite communication systems, as described with reference to Figures 1 and 2. The features of this disclosure are also described in the context of tracking systems, tracking receivers, and antenna systems, as described with reference to Figures 3–5C. These and other features of this disclosure are further illustrated and described with reference to apparatus diagrams and flowcharts of systems and methods for calibrating ground stations (e.g., GEO ground stations), as described with reference to Figures 6–8.

[0010] Figure 1 shows an example of a satellite communications system 100 that supports a system and method for calibrating a ground station according to the embodiments described herein. The satellite communications system 100 may use several network architectures, including a space segment 101 and a ground segment 102. The space segment 101 may include one or more satellites 120. The ground segment 102 may include one or more ground stations 130 (e.g., gateway terminals, ground stations), and network devices 141 such as a network operations center (NOC), satellite and gateway terminal command center, or other central processing center or device. Although ground stations 130 are considered, in other embodiments the techniques described herein may be applied to other devices such as other access node terminals (e.g., gateway terminals). Network devices 141 may be coupled with ground stations 130 and may control embodiments of communications system 100. In various embodiments, the network device 141 may be located in the same location as the ground station 130, or nearby, or it may be remotely installed and communicate with the ground station 130 and / or the network 140 via wired and / or wireless links. In some embodiments, the ground segment 102 may also include a user terminal 150 that receives communication services via satellite 120.

[0011] The user terminal 150 may include various devices configured to communicate signals with the satellite 120, including fixed terminals (e.g., ground-based fixed terminals) or mobile terminals such as those on boats, aircraft, or ground-based vehicles. The user terminal 150 may communicate data and information with the ground station 130 via the satellite 120. The data and information may be communicated to destination devices such as network device 141, or to several other devices or distributed servers associated with the network 140.

[0012] Ground station 130 may transmit a forward uplink signal 132 to satellite 120 and receive a return downlink signal 133 from satellite 120. Ground station 130 is an example of an access node and may also be known as a gateway, gateway terminal, or hub. Ground station 130 may include a ground station antenna system 131 and a ground station transceiver 135. The ground station transceiver 135 may include a tracking system 134. The ground station antenna system 131 may be capable of bidirectional communication and may be designed to have sufficient transmit power and receive sensitivity to reliably communicate with satellite 120. In some embodiments, the ground station antenna system 131 may include a parabolic reflector having high directivity in the direction of satellite 120 and low directivity in other directions. The ground station antenna system 131 may include various alternative configurations that may operate features such as high separation between orthogonal polarizations, high efficiency in the operating frequency band, and low noise.

[0013] When supporting communication services, the ground station 130 may schedule traffic to the user terminal 150. Alternatively, such scheduling may be performed in other parts of the communication system 100 (for example, in one or more network devices 141 which may include a network operations center (NOC) and / or a gateway command center). Although one ground station 130 is shown in Figure 1, embodiments of the present disclosure may be implemented in a communication system having multiple ground stations 130, each of which may be coupled to one another and / or to one or more networks 140.

[0014] The ground station 130 may provide an interface between the network 140 and the satellite 120, and in some embodiments, may be configured to receive data and information destined for the network 140 and one or more user terminals 150. The ground station 130 may format the data and information for distribution to each user terminal 150. Similarly, the ground station 130 may be configured to receive signals from the satellite 120 (e.g., from one or more user terminals 150) destined for destinations accessible via the network 140. The ground station 130 may also format received signals for transmission over the network 140.

[0015] Network 140 can be any type of network and may include, for example, the Internet, Internet Protocol (IP) networks, intranets, wide area networks (WANs), metropolitan area networks (MANs), local area networks (LANs), virtual private networks (VPNs), virtual LANs (VLANs), fiber optic networks, hybrid fiber optic coaxial networks, cable networks, public switched telephone networks (PSTNs), public switched data networks (PSDNs), public land mobile networks, and / or any other type of network that supports communication between devices as described herein. Network 140 may include both wired and wireless connections as well as optical links. Network 140 may connect the ground station 130 to other access node terminals that can communicate with the same satellite 120 or different satellites 120 or other vehicles.

[0016] Satellite 120 may be configured to support wireless communication between one or more terrestrial stations 130 and / or various user terminals 150 located in the service coverage area. In some embodiments, satellite 120 may be deployed and operate in GEO, such that its orbital position relative to terrestrial devices is relatively fixed or fixed within an operating tolerance or other orbital window (e.g., within an orbital slot). In other embodiments, satellite 120 may operate in any suitable orbit (e.g., low Earth orbit (LEO), medium Earth orbit (MEO), etc.).

[0017] Satellite 120 may include an antenna assembly 121 having one or more antenna feed elements. Each of the antenna feed elements may include, for example, a feed horn, a polarization transformer (e.g., a septum polarization horn that can function as two combined elements having different polarizations), a multi-port multi-band horn (e.g., a dual-band 20 GHz / 30 GHz having dual polarization LHCP / RHCP), a slotted cavity, an inverted F, a slotted waveguide, Vivaldi, helical, loop, patch, or any other configuration of antenna elements, or a combination of interconnected sub-elements. Each of the antenna feed elements may also include or be coupled to a radio frequency (RF) signal converter, a low noise amplifier (LNA), or a power amplifier (PA), and may be coupled to one or more transponders in satellite 120. Transponders may be used to perform signal processing such as amplification, frequency conversion, beamforming, etc.

[0018] In some embodiments, multiple frequency time-division multiple access (MF-TDMA) schemes may be used for the forward uplink signal 132 and the feedback uplink signal 173, enabling efficient streaming of traffic while maintaining flexibility in allocating capacity among user terminals 150. In these embodiments, some frequency channels may be allocated in a fixed manner, or alternatively, in a dynamic manner. A time-division multiple access (TDMA) scheme may also be employed for each frequency channel. In this scheme, each frequency channel may be divided into several time slots that can be allocated to connections (e.g., specific user terminals 150). In other embodiments, one or more of the forward uplink signal 132 and the feedback uplink signal 173 may be configured using other schemes such as frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), code division multiple access (CDMA), or any number of hybrid or other schemes known in the art. In various embodiments, the physical layer technique may be the same for each of the forward uplink signal 132, the feedback downlink signal 133, the forward downlink signal 172, or the feedback uplink signal 173, or some of the signals may use different physical layer techniques than the others.

[0019] When supporting communication services, satellite 120 may receive a forward uplink signal 132 from one or more ground stations 130 and provide a corresponding forward downlink signal 172 to one or more user terminals 150. Satellite 120 may also receive a feedback uplink signal 173 from one or more user terminals 150 and provide a corresponding feedback downlink signal 133 to one or more ground stations 130. Various physical layer transmission modulation and coding techniques may be used by ground stations 130, satellite 120, and user terminals 150 for signal communication (e.g., adaptive coding modulation (ACM)). Satellite 120 may include one or more transponders each coupled to one or more transmission antenna elements of one or more receiving elements and antennas, forming K receive / transmit paths having different radiation patterns (e.g., by using different combinations of frequency ranges and polarizations). Each of the K receive / transmit paths may be assigned as a forward path or a feedback path at any instant.

[0020] In some embodiments, satellite 120 is a single beam for communicating with ground station 130 ( Data may be communicated using a beam (which may be called a ground station beam, or more generally, an access node beam for an access node) and a single beam for communicating with user terminals 150 (which may be called a user beam). In some embodiments, each of these beams covers the service area of ​​satellite 120, which may span a large geographical area (e.g., half the Earth). In such cases, the ground station beam and the user beam may be called a broad beam. Also, communication resources (e.g., time and / or frequency resources) allocated to the communication system 100 may be shared among user terminals 150 within the coverage area of ​​user beam 125-b. In some embodiments, communication resources may be divided among user terminals 150 in terms of time and / or frequency, and separate communications may be transmitted to user terminals 150 via different communication resources. Additionally or alternatively, multiple user terminals 150 may use the same time and frequency resources, and separate communications may be transmitted to user terminals 150 via the same communication resources. If multiple user terminals 150 use the same time and frequency resources, the satellite communication system may apply spreading spectrum to separate communications before transmission. For example, a sequence (e.g., a pseudo-random sequence or orthogonal code) may be applied to separate communications before they are transmitted as combined signals over the same time and frequency resources.

[0021] In some embodiments, each sequence may be assigned to a different user terminal 150. Communication spread using sequences may be referred to as DSSS communication, and simultaneously transmitting transmissions for different users spread using unique sequences may be an example of CDMA technology. A user terminal 150 may determine the sequence to be used for communication to the user terminal 150 and apply that sequence to a combined signal to extract the signal components that carry the communication intended for the user terminal 150. A satellite 120 performing CDMA communication may include a plurality of spreaders and one or more power amplifiers coupled to the antenna elements of the spreaders and antenna arrays. In some embodiments, a separate data signal may be provided to each spreader, which can be given a plurality of spread signals by applying a unique spreading code to the data signal. The spread signals may be combined and provided to one or more power amplifiers, which can provide an amplified signal to the antennas of satellite 120.

[0022] In other embodiments, satellite 120 may communicate data using multiple beams covering the service area of ​​satellite 120 (for example, to increase the capacity of the communication system). That is, satellite 120 may communicate data using multiple beams arranged or tiled to cover the service area of ​​satellite 120. Some satellites 120 may include several transponders, each capable of independently receiving and transmitting signals. Each transponder may be coupled to one or more antenna elements (e.g., a receiving element and a transmitting antenna element) to form a receive / transmit signal path having a different radiation pattern (antenna pattern) than other receive / transmit signal paths, creating a unique beam that can be assigned to the same (e.g., using different frequency ranges or polarizations) or different beam coverage areas. In some cases, a single receive / transmit signal path may be shared across multiple beams using input and / or output multiplexers. In such cases, the number of simultaneous beams that can be formed may generally be limited by the number of receive / transmit signal paths deployed on the satellite.

[0023] In some embodiments, a ground station beam or user beam may be obtained via beamforming (and may be referred to as a “spot beam”). In such cases, ground station beam 125-a may be one of several ground station beams covering the service area of ​​satellite 120. Similarly, user beam 125-b may be one of several user node beams covering the service area of ​​satellite 120. Beamforming for a communication link may be performed by adjusting the phase (or time delay) and sometimes the amplitude of signals transmitted and / or received by multiple elements of one or more antenna arrays. This phase / amplitude adjustment is generally referred to as applying a “beam weight” or “beam coefficient” to the transmitted signal. For reception (by receiving elements of one or more antenna arrays), the relative phase and sometimes the amplitude of the received signal are adjusted so that the energy received from desired locations by multiple receiving antenna elements constructively overlaps (e.g., the same or different beam weights are applied). Within a spot beam, communication resources may be divided among user terminals, as similarly described with reference to communication using a broad beam. Furthermore, in some embodiments, the same set of communication resources may be shared by user terminals, as similarly described with reference to communication using a broad beam.

[0024] Satellite 120 may communicate with ground station 130 by transmitting a return downlink signal 133 and / or receiving a forward uplink signal 132 via one or more ground station beams (e.g., ground station beams 125-a which may be associated with each ground station beam coverage area 126-a). Ground station beams 125-a may support, for example, communication services for one or more user terminals 150 (e.g., relayed by satellite 120), or any other communications between satellite 120 and ground station 130. In some embodiments, ground station beam 125-a is one of several spot beams. Satellite 120 may communicate with user terminal 150 by transmitting a forward downlink signal 172 and / or receiving a return uplink signal 173 via one or more user beams (e.g., user beams 125-b which may be associated with each user beam coverage area 126-b). User beam 125-b may support communication services for one or more user terminals 150, or any other communications between satellite 120 and user terminals 150. In some embodiments, user beam 125-b is one of several spot beams. In some embodiments, satellite 120 may use either ground station beam 125-a or user beam 125-b to relay communications from ground station 130 to user terminals 150 (i.e., ground station 130 and user terminals 150 may share a beam).

[0025] To support beamforming operations, satellite 120 may use a phased array antenna assembly (e.g., a direct radiating array (DRA)), a phased array fed reflector (PAFR) antenna, or any other mechanism known in the art for receiving or transmitting signals (e.g., for communication or broadcasting services, or data acquisition services). A phased array antenna assembly may be used for both receiving uplink signals (e.g., a forward uplink signal 132, a feedback uplink signal 173, or both) and transmitting downlink signals (e.g., a feedback downlink signal 133, a forward downlink signal 172, or both). Relatively large reflectors may be illuminated by a phased array of antenna feeding elements, supporting the ability to create various patterns of spot beams within constraints set by the size of the reflectors and the number and arrangement of the antenna feeding elements.

[0026] Each antenna feed element may also include, or otherwise be coupled with, one or more transponders in satellite 120 that can perform other signal processing such as frequency conversion, beamforming, etc., including RF signal transducers, LNAs, phase shifters, or PAs. In some embodiments, each phase shifter may be coupled with one or more power amplifiers, and each power amplifier may be coupled with one or more antenna elements. In some embodiments, the phase shifters and / or weighting amplifiers may be located at ground station 130. Communications for different user terminals 150 may be provided to a set of phase shifters that generate a set of phase shift signals and provide the set of phase shift signals to a set of amplifiers. The set of amplifiers may amplify the phase shift signals (e.g., to different amplitudes) to obtain weighted signals and provide the weighted signals to a set of antenna elements. When emitted by the set of antenna elements, the weighted signals can be combined constructively and / or destructively so that the weighted signals form a single signal focused to a geographic area of ​​a larger geographic area serviced by satellite 120. A transponder coupled with multiple antenna feeding elements may be capable of performing beamforming communications.

[0027] The ground station 130 may perform phase calibration in the tracking system 134 of the ground station transceiver 135. The tracking system 134 may include or communicate with an antenna control unit for controlling the ground station antenna system 131. In some embodiments, the ground station antenna system 131 may also be referred to as an antenna or antenna assembly. As further described herein, the ground station 130 may transmit a forward uplink signal 132 to the satellite 120 via the control ground station antenna system 131 and receive a return downlink signal 133 from the satellite 120 via the control ground station antenna system 131. In some embodiments, such communication may be in one or more of the S band, X band, Ku band, Ka band, Q band, V band, or other similar signal bands in other embodiments (e.g., J band, K band, L band, or some combination thereof). The tracking system 134 may track the satellite 120 so that the ground station 130 can communicate with the satellite 120.

[0028] The tracking system 134 may require calibration of the phase difference in the signal paths of the sum and difference signals via the ground station antenna system 131 and the tracking receiver of the tracking system 134. Initial phase calibration may be performed in connection with the installation and setup of the tracking system 134. Furthermore, during operation, phase calibration may be performed to compensate for phase offset changes due to temperature changes in the ground station 130 and its components. In addition, certain components of the ground station 130 (e.g., ground station antenna system 131, ground station transceivers including those in the tracking system 134) may experience phase shifts over time. In particular, the amplifiers of the tracking system 134 (e.g., low-noise block down converters (LNBs)) may experience phase offset instability over time with temperature, and over time with a constant temperature.

[0029] As will be further discussed herein, the tracking system 134 and one or more of its components may perform an initial phase calibration, which may include a characterization procedure. The characterization procedure may include a calibration output generated by a tracking receiver (not shown) in the tracking system 134 for each frequency in a set of frequencies. The calibration signal is coupled back to a first input of the tracking receiver for a first path from the antenna and coupled back to a second input of the tracking receiver for one second from the tracking feed. The phase value at each frequency in the set of frequencies may be determined to generate a first set of phase values ​​corresponding to the set of frequencies for a particular receiver in the tracking system. In some embodiments, calibration coefficients associated with a particular receiver may then be stored. For example, a line may be fitted to a set of phase values ​​for a frequency, and the slope and offset of the stored fitted line may be determined. Alternatively, the phase value itself may be stored. This characterization procedure may also be performed on each other's receivers in the tracking system 134. In some embodiments, the difference in phase values ​​between different receivers at each frequency may be stored.

[0030] Subsequently, during operation, the ground station 130 may receive communication signals on a first frequency (which may also be called a carrier frequency) and, for example, return downlink signals 133 from satellite 120 at the ground station antenna system 131. The communication signals may follow a first path via a first path to a first input of the tracking receiver of the tracking system 134, and a second path via a second path (e.g., a tracking path) to a second input of the tracking receiver.

[0031] For the same duration that the communication signal is being received by the tracking receiver (for example, over a period of time without interruption to the reception of the communication signal), the tracking receiver may output a calibration signal coupled to a first path received at a first input and coupled to a second path received at a second input. The calibration signal may be output by the tracking receiver at a second frequency different from the first frequency of the received communication signal. In some embodiments, the calibration signal may be one of the frequency sets used in the characterization procedure described herein. In other embodiments, the calibration signal may be a frequency within the range of the frequency set, but not one of the frequencies used in the characterization procedure.

[0032] A tracking system 134 (for example, in a tracking receiver) may determine a phase value of a second frequency based on a calibration signal received at a first input and a calibration signal received at a second input. Using stored calibration coefficients (e.g., phase offset between the first and second frequencies), the tracking receiver may determine (e.g., extrapolate, calculate, etc.) a second phase value associated with the first frequency of the communication signal from the phase value of the second frequency. In some embodiments, the tracking system 134 may also determine a second phase offset from stored calibration coefficients. The second phase offset may be between a first receiver and a second receiver of the tracking receiver. The first receiver may be used for the first frequency for the communication signal, and the second receiver may be used for the second frequency for the calibration signal. The second phase offset may also be used to determine a second phase value associated with the first frequency, thereby taking into account the phase difference between different frequencies and receivers. The tracking system 134 can then generate a phase correction value for the received signal of the first frequency. The phase correction value can then be used in the tracking procedure.

[0033] Table 1 below shows exemplary characterization data that can be used to determine the receiver calibration coefficient. In one embodiment, a tracking receiver (e.g., a calibration component of the tracking receiver) may determine the slope (m) and offset (b) of the optimal fit line for each receiver of the tracking receiver based on characterization data. In some embodiments, the slope and offset may also be determined due to the phase difference between the first receiver and the second receiver. The receiver calibration coefficient may then be an index of these slopes and offsets associated with each receiver.

[0034] During calibration, the tracking receiver may use phase calibration data to determine the phase associated with the first frequency communication signal from the second frequency calibration signal without interrupting the communication signal. For example, according to the characterization data shown in Table 1, the communication signal may be at 8200 MHz (which may be received by the first receiver of the tracking receiver), and the calibration signal may be at a frequency of 7750 MHz (which may be received by the second receiver of the tracking receiver). The tracking receiver may determine that the phase at the second receiver for the calibration signal is -89 degrees. The tracking receiver (e.g., the calibration component of the tracking receiver) may then add a phase offset of 123.2 degrees at 8200 MHz (the phase difference between the first and second receivers) (as indicated by the receiver calibration coefficient) to reach 34.2 degrees. A tracking receiver (e.g., a calibration component of a tracking receiver) can then add a phase offset of -31 degrees (indicated by the receiver's calibration coefficient), which is -120.1 degrees minus -89.0 degrees, to the second receiver (the phase difference between 8200 MHz and 7750 MHz for the second receiver), and then arrive at 3.2 degrees. In this embodiment, 3.2 degrees then represents the phase of the communication signal at the first frequency (8200 MHz), and this can be used to generate a phase correction value for the communication signal without interrupting the reception of the communication signal.

[0035] Figure 2 shows an example of a satellite communications system 200 supporting a system and method for calibrating a ground station according to embodiments described herein. The satellite communications system 200 shows a satellite 220 and a ground station 230 in block diagram form. In some embodiments, the satellite communications system 200 may be implemented by one or more embodiments of the satellite communications system 100. For example, the satellite 220 and ground station 230 are examples of the satellite 120 and ground station 130, respectively, as illustrated and described with reference to Figure 1, and may perform one or more of their functions. Although only one satellite 220 is shown, the satellite 220 may represent one or more satellites or satellite networks according to other embodiments. The satellite 220 may transmit a downlink signal 233 to the ground station 230, and the satellite 220 may receive an uplink signal 232 from the ground station 230.

[0036] The ground station 230 may include a tracking system 205 which may include one or more components shared with other functional blocks of the ground station 230 (for example, as part of the ground station transceiver). For example, the tracking system 205 may include an antenna and an antenna controller unit 240, the antenna controller unit may also be considered part of other functional blocks of the ground station 230. In other embodiments, the tracking system 205 may communicate with the antenna controller unit 240, but may be considered separate from the antenna controller unit 240.

[0037] The tracking system 205 may include a tracking receiver 210 coupled to an antenna controller unit. Details of embodiments of the tracking receiver 210 are further described herein, for example, with reference to Figure 4A. The tracking receiver 210 may also include calibration components, which may implement 255, 265, 270, and 280, the functions of which will be further described.

[0038] During operation, the ground station 230 may receive communication signals at a first frequency of the channel (which may also be called the carrier frequency) and, for example, return downlink signals 233 from satellite 220 at the ground station 230. The antenna and antenna controller unit 240 may provide a path 250 for communication signals to the input of the tracking receiver 210. The tracking receiver 210 may also output calibration signals on a path 245 which may be coupled with one or more components of the antenna and antenna controller unit 240, including the path 250 to the first input of the tracking receiver 210. The calibration signals may be at a second frequency different from the first frequency. In some embodiments, the second frequency may be on the same channel as the first frequency (e.g., the same RF spectral band). For example, the ground station 230 may be configured to receive at different frequencies across the RF spectral band, for example, a range of frequencies within the X band (e.g., about 7750 MHz to about 8250 MHz). In other embodiments, other frequencies may be used, including other RF spectral bands (e.g., Ka band, Ku band, C band, etc.) or two or more entire RF spectral bands.

[0039] The tracking receiver 210 may include a plurality of receivers, including at least a first receiver for communication signals on path 250 and a second receiver for calibration signals on path 245. As further described herein, the calibration signals may be received by the tracking receiver 210 concurrently (e.g., in parallel, contemporaneously) with the communication signals received from satellite 220. That is, ground station 230 can communicate without interruption while performing calibration. The communication signals may be received by the first receiver, and the calibration signals may be received by the second receiver. The tracking receiver 210 may determine a calibration value associated with the second receiver at a second frequency 255. This calibration value may represent a first phase value 260 at the second frequency. Next, the tracking receiver may adjust the first phase value associated with the second receiver at the second frequency in 265 to the phase value associated with the first receiver and the second frequency according to a phase offset identified from the receiver calibration coefficient (for example, the phase offset provides a mapping between the phase associated with the first receiver and the phase associated with the second receiver). The phase value associated with the second frequency may then be further adjusted in 270 to a second phase value 275 associated with the first frequency according to a phase offset identified from the receiver calibration coefficient (for example, the phase offset provides a mapping between the phase associated with the first frequency and the phase associated with the second frequency, for example, for the first receiver). From the second phase value adjusted from the second frequency for the calibration signal to the first frequency for the communication signal, a phase compensation value for the first receiver may be generated in 280 for use in phase calibration.

[0040] Figure 3 shows an example of a tracking system 300 that supports a system and method for calibrating a ground station according to the embodiments described herein. In some embodiments, the tracking system 300 may be implemented by one or more embodiments of the satellite communication system 100 and / or the satellite communication system 200. For example, the tracking receiver 350 may be an example of the tracking receiver 210 described with reference to Figure 1 and / or the tracking receiver 210 described with reference to Figure 2, and the tracking system 300 may be an example of the tracking system 134 described with reference to Figure 1 and / or the tracking system 205 described with reference to Figure 2.

[0041] The tracking system 300 may include or be coupled to an antenna 301 for receiving downlink signals. Antenna 301 may be coupled to a polarizer 305 that directs the received signal along path 306 to a diplexer 310 for a first polarization type (e.g., right-hand circular (RHC) polarization). Path 306 may form part of a first path from antenna 301 to a tracking receiver 350. Path 380 may be coupled to a diplexer 310 coupled to a first amplifier component 320. The first amplifier component 320 is coupled to a first input 330 of the tracking receiver 350.

[0042] Polarizer 305 may also direct the received signal along path 307 to diplexer 315 for a second polarization type (e.g., left-hand circular polarization (LHC) polarization). Path 307 may form part of a third path from antenna 301 to tracking receiver 350. The received signal may be coupled with the signal from path 385 of diplexer 315, which is coupled to a second amplifier component 325. The second amplifier component 325 is coupled to a third input 335 of tracking receiver 350.

[0043] The tracking receiver 350 may also be coupled to a tracking feed 360. In some embodiments, the tracking feed may couple a set of antennas, including antennas 302, 302-b, 302-c, and 302-d, to a diplexer 365 via a switch 355, which is coupled to an amplifier component 395. The amplifier component 395 may be coupled to a second input 345 of the tracking receiver 350. The switch 355 may select one of antennas 302, 302-b, 302-c, or 302-d and couple to the tracking receiver 350 for the tracking feed 360, for example, while performing tracking of a satellite that a ground station is communicating with.

[0044] The tracking receiver 350 may provide a calibration output 340 coupled to a distributor 375. The distributor 375 may be coupled to a diplexer 310 via path 380, to a diplexer 315 via path 385, and to a diplexer 365 via path 390. Thus, the calibration signal output by the tracking receiver 350 may be output by the tracking receiver 350 and received back by the tracking receiver 350 at the first input 330, the second input 345, and the third input 335.

[0045] The tracking receiver 350 may include a plurality of receivers, including a first receiver 351, a second receiver 352, a third receiver 354, and a calibration component 353.

[0046] A first receiver 351 may be coupled to a first input 330 and a second input 345 and may output values ​​to a calibration component 353. The first receiver 351 may be configured to be tuned to receive a signal of a first frequency (or the tracking receiver 350 may be tuned to provide to the first receiver 351). The calibration component 353 may then determine a phase value (e.g., phase offset, phase difference) between a communication signal of a first frequency received at the first input 330 via a first path to the antenna 301 and the tracking receiver 350 and a signal communication signal of a first frequency received at the first input 330 via a first path to the antenna 301 and the tracking receiver 350.

[0047] A second receiver 352 may be coupled to the first input 330 and the second input 345 and may output a value to a calibration component 353. The second receiver 352 may be tuned to receive a signal of a second frequency (or the tracking receiver 350 may be tuned to provide a signal to the second receiver 352). The calibration component 353 may then determine the phase value (e.g., phase offset, phase difference) between a second frequency calibration signal output by the tracking receiver 350 via the calibration output 340 and received at the first input 330 via the first path from path 380 to the tracking receiver 350, and a second frequency calibration signal output by the tracking receiver 350 via the calibration output 340 and received at the second input 345 via the second path from path 390 to the tracking receiver 350.

[0048] The calibration component 353 may determine a phase correction value for the first frequency communication signal using a set of calibration coefficients, along with a phase value of a first frequency associated with the communication signal and a phase value of a second frequency associated with the calibration signal. In some embodiments, the calibration component 353 may perform features of the tracking receiver 210 described with reference to Figure 2, particularly features 255, 265, 270, and 280.

[0049] In some embodiments, one or more of the first amplifier component 320, the second amplifier component 325, or the amplifier component 395 may be or include an LNB. An LNB may be a device used to downconvert frequencies and amplify a signal for further processing. In some embodiments, an LNB may be or include a low-noise amplifier (LNA), a downconvert mixer, a local oscillator, and an intermediate frequency amplifier. An LNB may amplify a signal received from a satellite and downconvert higher frequency signals to lower intermediate frequency (IF) signals. In some embodiments, the use of an LNB with the techniques described herein may eliminate the need for a phase-matched LNA and may allow the use of a lower-cost LNB.

[0050] Figure 4 shows an example of a tracking system 400 that supports a system and method for calibrating a ground station according to the embodiments described herein. In some embodiments, the tracking system 400 may be implemented by one or more embodiments of the satellite communication system 100 and / or the satellite communication system 200. For example, the tracking receiver 450 may be an example of the tracking receiver 210 described with reference to Figure 1 and / or the tracking receiver 210 described with reference to Figure 2 and / or the tracking receiver 350 described with reference to Figure 3, and the tracking system 400 may be an example of the tracking system 134 described with reference to Figure 1 and / or the tracking system 205 described with reference to Figure 2 and / or the tracking system 300 described with reference to Figure 3.

[0051] The tracking system 400 may include or be coupled to antenna 401 for receiving downlink signals. Antenna 401 may be coupled to a turnstile junction 402, which may then be coupled to a tracking coupler 403. The tracking coupler 403 may be coupled to a polarizer 405 and a monopulse network 404. Polarizer 405 may direct the received signal along path 406 to a diplexer 410 for a first polarization type (e.g., right-hand circular (RHC) polarization). Path 406 may form part of a first path from antenna 401 to a tracking receiver 450. Path 480 may be coupled to a diplexer 410 coupled to a first amplifier component 420. The first amplifier component 420 is coupled to a first input 430 of the tracking receiver 450.

[0052] Polarizer 405 may also direct the received signal along path 407 to diplexer 415 for a second polarization type (e.g., left-hand circular polarization (LHC) polarization). Path 407 may form part of a third path from antenna 401 to tracking receiver 450. The received signal may be coupled with the signal from path 485 of diplexer 415, which is coupled to a second amplifier component 425. The second amplifier component 425 is coupled to a third input 435 of tracking receiver 450.

[0053] The tracking receiver 450 may also be coupled to a tracking feed 460. In some embodiments, the tracking feed may couple the antenna 401 to a diplexer 465 via a tracking coupler 403. The diplexer 465 may then be coupled to an amplifier component 495. The amplifier component 495 may be coupled to a second input 445 of the tracking receiver 450. The tracking coupler 403 may be used to provide a signal of a first frequency (e.g., a tracking signal) to the communication signal while the ground station performs tracking of the satellite it is communicating with. In some embodiments, the tracking coupler 403 may be a TE21 coupler. In the case of a TE21 coupler, the phase states are 0, 90, 180, and 270. The TE21 orthogonality, which orthogonals the azimuth / elevation angles, may prevent switching because it separates the azimuth / elevation angles.

[0054] The tracking receiver 450 may provide a calibration output 440 coupled to a distributor 475. The distributor 475 may be coupled to a diplexer 410 via path 480, to a diplexer 415 via path 485, and to a diplexer 465 via path 490. Thus, the calibration signal output by the tracking receiver 450 may be output by the tracking receiver 450 and received back by the tracking receiver 450 at the first input 430, the second input 445, and the third input 435.

[0055] The tracking receiver 450 may include a plurality of receivers, including a first receiver 451, a second receiver 452, a third receiver 454, and a calibration component 453.

[0056] A first receiver 451 may be coupled to a first input 430 and a second input 445 and may output values ​​to a calibration component 453. The first receiver 451 may be configured to be tuned to receive a signal of a first frequency (or the tracking receiver 450 may be tuned to provide to the first receiver 451). The calibration component 453 may then determine the phase value (e.g., phase offset, phase difference) between a first frequency communication signal received at the first input 430 via a first path to antenna 401 and tracking receiver 450 and a first frequency signal communication signal received at the first input 430 via a first path to antenna 401 and tracking receiver 450.

[0057] A second receiver 452 may be coupled to the first input 430 and the second input 445 and may output a value to a calibration component 453. The second receiver 452 may be tuned to receive a signal of a second frequency (or the tracking receiver 450 may be tuned to provide to the second receiver 452). The calibration component 453 may then determine the phase value (e.g., phase offset, phase difference) between the second frequency calibration signal output by the tracking receiver 450 via the calibration output 440 and received at the first input 430 via the first path from path 480 to the tracking receiver 450, and the second frequency calibration signal output by the tracking receiver 450 via the calibration output 440 and received at the second input 445 via the second path from path 490 to the tracking receiver 450.

[0058] The calibration component 453 may determine a phase correction value for the first frequency communication signal using a set of calibration coefficients, along with a phase value of a first frequency associated with the communication signal and a phase value of a second frequency associated with the calibration signal. In some embodiments, the calibration component 453 may perform features of the tracking receiver 210 described with reference to Figure 2, particularly features 255, 265, 270, and 280.

[0059] In some embodiments, one or more of the first amplifier component 420, the second amplifier component 425, or the amplifier component 495 may be or include an LNB. An LNB may be a device used to downconvert frequencies and amplify a signal for further processing. In some embodiments, an LNB may be or include an LNA, a downconvert mixer, a local oscillator, and an intermediate frequency amplifier. An LNB may amplify a signal received from a satellite and downconvert higher frequency signals to lower intermediate frequency (IF) signals. In some embodiments, the use of an LNB with the techniques described herein may eliminate the need for a phase-matched LNA and may allow the use of a lower-cost LNB.

[0060] Figure 5 shows an example of a tracking system 500 supporting a system and method for calibrating a ground station according to embodiments described herein. In some embodiments, the tracking receiver 500-a may be an example of a part or embodiment of the tracking receiver 350 or the tracking receiver 450.

[0061] As an example, the tracking receiver 500-a may include a total input 521 (SUM) (which may be an example of a first input 330 or 430), a difference input 531 (DIFF) (which may be an example of a second input 345 or 445), a first analog-to-digital (A / D) converter 541, a second A / D converter 551, a digital signal processor (DSP) 505, and a calibration output 571. The first A / D converter 541 may be coupled between the total input 521 and the DSP 505. The first A / D converter 541 may be configured to convert the signal received at the total input 521 into a total digital signal and provide the total digital signal to the DSP 505. The second A / D converter 551 may be coupled between the difference input 531 and the DSP 505. The second A / D converter 551 may be configured to convert the signal received at the difference input 531 into a difference digital signal and provide the difference digital signal to the DSP 505. Calibration output 571 may be coupled to total input 521 (e.g., via a first path further described herein) and to difference input 531 (e.g., via a second path further described herein). Tracking receiver 500-a may be configured to generate a calibration signal and provide the calibration signal through calibration output 571.

[0062] In a more detailed aspect of this disclosure, the DSP 505 may be configured to generate a phase correction value PC1 based on a total digital signal and a difference digital signal resulting from a calibration signal coupled to the total input 521 and the difference input 531. The DSP 505 may be further configured to store the phase correction value. The phase correction value may correspond to the phase difference between the total digital signal and the difference digital signal. A first calibration signal insertion component (not shown) may be coupled between a calibration output 571 and a total input 521 to define a first signal path between the total input 521 and the first calibration signal insertion component. A second calibration signal insertion component (not shown) may be coupled between a calibration output 571 and a difference input 531 to define a second signal path between the difference input 531 and the second calibration signal insertion component. The first and second signal paths may have different phase shifts due to one or more components along their respective signal paths. The DSP505 may be configured to generate a phase correction value (e.g., PC1) based on the phase difference between the first signal path and the second signal path in response to a calibration signal.

[0063] The calibration signal can be generated by the DSP 505 using a configurable direct digital synthesizer (DDS) 510. The DDS 510 outputs a digital calibration signal to a digital-to-analog converter (DAC) 520. The DAC 520 outputs a calibration signal at the calibration output 571 based on the digital calibration signal. This calibration signal can also be generated using a phase-locked loop (PLL) and a voltage-controlled oscillator (VCO) (not shown). Two voltage-controlled amplifiers 530 and 540 can set the levels of the signals input to the A / D converters 541 and 551, respectively. The differential phase detector 515 detects the phase difference (or phase offset) between the digital sum signal and the digital difference signal output by the A / D converters 541 and 551, respectively. The differential phase detector 515 generates a phase correction value based on the detected phase difference and provides the phase correction value to the phase adjustment rotator 560. In the example shown, the phase adjustment rotator 560 digitally adjusts the phase of the digital difference signal in this example. More generally, the phase of the digital sum signal and / or the phase of the digital difference signal can be adjusted using the phase correction value to phase-match (or phase-align) the two signals. The adjusted digital difference signal is combined with the digital sum signal by the combination / sum operation 570.

[0064] In a more detailed aspect of the present disclosure, the differential phase detector 515 can use complex conjugate multiplication, as well as complex integration and dumping. An instantaneous estimated value of the phase offset can be calculated using complex conjugate multiplication. The sum signal can be modeled by e (jωt+θ1) and the difference signal can be modeled by e (jωt+θ2) Complex conjugate multiplication can result in the following: CC instant =e (jωt+θ1) *e -1*(jωt+θ2) =e (jωt+θ1-jωt-θ2) =e (θ1-θ2) =cos(θ1 - θ2)-jsin(θ1 - θ2) This instantaneous phase estimate can be averaged using complex integration and dumping. The value can be accumulated over 2 N samples, and the accumulated result can be divided by 2 N CC ave =(1 / 2 N )Σ[cos(θ1-θ2)-jsin(θ1-θ2)] The averaged complex result can be input into an arctangent function to reconstruct the phase offset value. TIFF0007855582000002.tif6170

[0065] The phase adjustment rotator 560 can phase-rotate the digital difference signal to remove the phase offset between the sum signal and the difference signal. The phase adjustment rotator 560 receives the difference digital signal and the resulting phase offset value and outputs a phase-rotated complex value.

[0066] In some embodiments, phase calibration may be performed at multiple frequencies within the operating bandwidth of the tracking system by generating a continuous wave (CW) tone at each step and performing phase error calibration at each step. The steps may be selected to correspond, for example, to a predetermined maximum value of the phase mismatch (e.g., a phase difference of about 20 degrees in the worst-case scenario). Thus, the steps may be selected to allow for easy interpolation between steps.

[0067] The tracking receiver of the tracking system 134, integrated with the tracking feed, may perform phase matching of the RF signal path within the digital domain of the DSP 505 by injecting a calibration signal into the signal path. The tracking receiver of the tracking system 134 may transmit and receive a calibration signal to perform phase calibration. During tracking mode, the tracking receiver of the tracking system 134 may also output tracking error signals to an ACU (not shown), e.g., the antenna and antenna controller unit 240 in Figure 2, via a digital signal (e.g., an Ethernet message) rather than via an analog signal over an expensive RF cable.

[0068] These embodiments may enable cost reductions in the system components. Phase-matched LNAs may no longer be required, thus enabling the use of lower-cost LNBs. Azimuth / elevation switching control and ACU functionality may be moved into the tracking receiver of the tracking system 134, thus reducing the wiring required between the ACU and the tracking receiver of the tracking system 134. ACU functionality may also be moved to the tracking receiver, for example, bin integration. Aligning and combining the total and difference signals in the DSP 505 of the tracking receiver of the tracking system 134 using calibration may offer several advantages. For example, external phase shifters and couplers can be eliminated by creating phase shifters and couplers within the DSP 505. Furthermore, labor costs in the construction of the tracking system 134 can be reduced. Delay and phase can be characterized, but matching between total and difference channels may not be required. Characterizing or measuring phase is far simpler than physically cutting cables to match phase.

[0069] Figure 5B shows an example of an antenna system 500-b supporting a system and method for calibrating a ground station according to embodiments described herein. In some embodiments, the antenna system 500-b may be a subset of the ground station antenna system 131. Antenna 545 may be a central feed horn and four periphery offset antennas 550-N which may be smaller feed horns, or may include them. In some embodiments, antenna 545 may be an example of antenna 301 and / or antenna 401.

[0070] Two of the offset antennas, 550-a and 550-b, may be used for elevation tracking and may be positioned above and below antenna system 500-b. Two of the offset antennas, 550-c and 550-d, may be used for horizontal (azimuth) tracking and may be positioned to the left and right of antenna system 500-b.

[0071] Antenna system 500-b may be aligned to the antenna boresite, and offset antenna 550-N may be offset at a slight angle from the boresite. Antenna system 500-b may be used to acquire data from a satellite (or other signal source) because it has the greatest sensitivity. The sum signal from antenna system 500-b may be used to normalize the difference signal from offset antenna 550-N in order to maintain a constant error gradient when the range to the satellite is changing. Since the signal variation due to the range is common to all antennas, normalizing the difference signal to the sum signal maintains a constant difference path error gradient. The signal from offset antenna 550-N is used to generate a tracking signal.

[0072] Figure 5C shows an example of an antenna system 500-c supporting a system and method for calibrating a ground station according to embodiments described herein. In some embodiments, the antenna system 500-c may be a subset of the ground station antenna system 131. Antenna 555 may be or include a central feed horn (e.g., without surrounding offset antennas). In some embodiments, antenna 555 may be an example of antenna 301 and / or antenna 401. Antenna 555 may be coupled to a tracking coupler such as a tracking coupler 403 for vertical (elevation) tracking and horizontal (azimuth) tracking.

[0073] Characterization of the phase shift (or phase offset or delay) associated with each frequency in the frequency set for the signal path through the antenna system 500-c may be performed once, for example, during or immediately after installation, as further described herein. In one embodiment, the characterization may be performed at room temperature. In other embodiments, different ambient temperatures may be used.

[0074] Figure 6 shows an example of a ground station 630 supporting a system and method for calibrating a ground station according to the embodiments described herein. Ground station 630 may be an example of, or may include, components of, ground stations 130 or 230 as described with reference to Figures 1 and 2. Ground station 630 may include components for bidirectional communication, including components for transmitting and receiving components and components for processed data received in communication. Ground station 630 may include an antenna 605, a transceiver 610, a communication manager 615, a processor 620, a tracking system 640, a memory 650, and a network interface 660.

[0075] Antenna 605 may be configured to receive or transmit information to or from a satellite using RF signals. Antenna 605 may be or include a parabolic antenna. In some embodiments, antenna 605 may be an example of antenna system 500-b or 500-c described with reference to Figures 5B and 5C. To receive signals, antenna 605 may reflect received signals to the focal point where the antenna feed passes the signal to the receiving chain. To transmit signals, antenna 605 may reflect signals emitted from the antenna feed at the focal point.

[0076] The transceiver 610 may communicate bidirectionally with another wireless transceiver. The transceiver 610 may also include a modem for modulating a signal and providing the modulated signal to the antenna 605. The modem may also demodulate the signal received from the antenna 605. The transceiver 610 and the antenna 605 may be examples of a receiver, a transmitter, or both.

[0077] The processor 620 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, the processor 620 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into the processor 620. The processor 620 may be configured to execute computer-readable instructions stored in memory (e.g., memory 650) to cause the ground station 630 to perform various functions (e.g., functions or tasks supporting communications for collision detection / warning). For example, the ground station 630 or components of the ground station 630 may include the processor 620 and memory 650 coupled to the processor 620, which are configured to perform various functions described herein.

[0078] Memory 650 may include random access memory (RAM) and read-only memory (ROM). Memory 650 may store computer-readable and computer-executable code. The code may include instructions that, when executed by processor 620, cause ground station 630 to perform various functions described herein. Code 655 may be stored in a non-temporary computer-readable medium such as system memory or another type of memory. In some cases, code 655 may not be directly executable by processor 620, but (for example, when compiled and executed) may cause a computer to perform functions described herein. In some cases, memory 650 may include a basic I / O system (BIOS) that can control basic hardware or software operations, such as interaction with peripheral components or devices.

[0079] The communications manager 615 may support satellite communications. In some embodiments, the communications manager 615 is used to form a beam that spans a coverage area. The communications manager 615 may also be used to handle mobility events such as handing over a user terminal between the satellite beam and the satellite, or handing over a non-GEO satellite between a GEO satellite and a GEO satellite. The communications manager 615 may also be used to schedule communications resources for different devices, generate data messages according to satellite protocols, and map symbols to communications resources.

[0080] In some embodiments, the communications manager 615 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise cooperating with the transceiver 610, the antenna 605, or any combination thereof. Although the communications manager 615 is shown as a separate component, in some embodiments, one or more functions described with reference to the communications manager 615 may be supported or performed by the processor 620, memory 650, code 655, or any combination thereof. For example, code 655 may include instructions executable by the processor 620 to cause the ground station 630 to perform various forms of lens communication with a plurality of antenna arrays as described herein, or the processor 620 and memory 650 may be configured to perform or support such operations in a different manner.

[0081] The network interface 660 may be configured to send and receive information to and from other networks (e.g., the Internet, cellular networks, telephone networks, private networks, government networks, etc.). The network interface 660 may translate messages from one protocol to another (e.g., from satellite-based protocols to Internet protocols).

[0082] The tracking system 640 may be configured to support a system and method for calibrating a ground station. In some embodiments, the tracking system 640 may receive a first signal of a first frequency and a calibration signal of a second frequency via a first path at a first input of the tracking receiver 642. The tracking system may also receive a first signal of a first frequency and a calibration signal of a second frequency via a second path at a second input of the tracking receiver 642. The tracking system 640 may further output the calibration signal to a first coupler coupled to the first path and a second coupler coupled to the second path. The tracking system 640 may then determine a first phase value of the second frequency based at least in part on the calibration signal of the second frequency received at the first and second inputs. The tracking system 640 may then determine a second phase value associated with the first frequency from the first phase value based at least in part on a first phase offset between the first frequency and the second frequency. A first phase offset can be determined at least in part on a first receiver calibration coefficient set. Based at least in part on a second phase value, the tracking system 640 can then generate a phase correction value for the signal of the first frequency received via antenna 605.

[0083] In some embodiments, the tracking receiver 642 may include multiple receivers that can be used to receive signals of different frequencies simultaneously (same time) (e.g., concurrently). For example, the tracking receiver 642 may include a first receiver for a first signal of a first frequency and a second receiver for a calibration signal of a second frequency. Each receiver may have different effects on the phase of the received signal due to differences in the receiver's temperature, structure, design, etc. Therefore, a second phase value associated with a first frequency may be determined at least in part on a second phase offset between the first receiver for the first frequency and the second receiver for the first frequency. This second phase offset may be determined at least in part on a first set of receiver calibration coefficients. In some embodiments, the second phase offset between the first and second receivers may be based on receiver calibration coefficients determined during a characterization performed during or after the installation of the ground station 630. In some embodiments, the second phase offset may be determined from the first set-off receiver calibration coefficient, at least in part, based on the gradient and offset, or temperature, or a combination thereof, which are stored as receiver calibration coefficients.

[0084] The tracking system 640 may also perform calibration at specific time intervals (e.g., periodically or according to a schedule). Thus, the tracking system 640 may identify time intervals for performing calibration (e.g., periodic time intervals) and generate updated phase correction values ​​for a first signal received through the antenna at a first frequency according to the periodic time intervals.

[0085] In some embodiments, the tracking feed may be a set of antennas offset from an antenna configured to receive a first signal of a first frequency, or coupled thereto. The set of antennas may be coupled to a second input via a second path. In other embodiments, the antenna feed may include a tracking coupler coupled to a first path for receiving a first signal of a first frequency. The tracking coupler may be coupled to a second input via a second path.

[0086] In some embodiments of the tracking system 640, the ground station 630 may store multiple receiver calibration coefficient sets. For example, a first receiver calibration coefficient set may be associated with a first path (e.g., tracking receiver 642 at a first input from antenna 605), and a second receiver calibration coefficient set may be associated with a second path (e.g., tracking receiver 642 at a third input from antenna 605). In some embodiments, the first path may be associated with a first polarization type (e.g., left-hand circular polarization), and the first receiver calibration coefficient set may be associated with the first path. The ground station 630 may also be configured to receive a second polarization type (e.g., right-hand circular polarization). In such a case, a second receiver calibration coefficient set may be associated with a second path. In some embodiments, the second receiver calibration coefficient set may be associated with the difference between the first path and the second path, or the difference between the first receiver for the first path and the second receiver associated with the second path, or both. The tracking receiver 642 may include a third input coupled to antenna 605 to receive the first signal via the second path.

[0087] According to some embodiments of the tracking system 640, the tracking receiver 642 may output calibration signals for each frequency in a frequency set from its calibration output. The tracking system 640 may then receive the output calibration signals at a first input and a second input and determine a first set of phase values ​​associated with a first receiver of the tracking receiver 642. In some embodiments, the first receiver is coupled to both the first and second inputs. The tracking receiver 642 may then determine a second set of phase values ​​associated with a second receiver of the tracking receiver 642, the second receiver is also coupled to both the first and second inputs. The tracking receiver may then generate a first set of receiver calibration coefficients based at least in part on the first and second set of phase values.

[0088] In some embodiments of the tracking system 640, generating a first receiver calibration coefficient set based at least partially on a first phase value set and a second phase value set includes determining a first slope and a first offset for a first line that fits the difference between the first phase value set and the second phase value set as a function of frequency, and determining a second slope and a second offset for a second line that fits the first phase value set as a function of frequency. In some embodiments, the receiver calibration coefficient set includes at least a first slope, a first offset, a second slope, and a second offset.

[0089] In some embodiments, the tracking system 640, the tracking receiver 642, the antenna controller unit 644, the communication manager 615, the transceiver 610, or various combinations or components thereof may be implemented in hardware (e.g., in a communication management circuit). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gates or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting means for performing the functions described herein. In some embodiments, the processor and memory coupled to the processor may be configured to perform one or more of the functions described herein (e.g., by the processor executing instructions stored in memory).

[0090] Additionally or alternatively, the tracking system 640, the tracking receiver 642, the antenna controller unit 644, the communications manager 615, the transceiver 610, or various combinations or components thereof may be implemented in code 655 executed by the processor 620 (for example, as communications management software or firmware). When implemented in code 655 executed by the processor 620, the functions of the tracking system 640, the tracking receiver 642, the antenna controller unit 644, the communications manager 615, the transceiver 610, or various combinations or components thereof may be performed by a general-purpose processor, a DSP, a central processing unit (CPU), an ASIC, an FPGA, or any combination thereof or other programmable logic device (for example, configured or otherwise supporting as means for performing the functions described herein).

[0091] Figure 7 shows a flowchart illustrating Method 700, which supports a system and method for calibrating a ground station, as disclosed herein. The operation of Method 700 may be implemented by ground devices, e.g., ground stations 130, 230, 630, or their components, as described herein. For example, the operation of Method 700 may be performed by a ground station transceiver 135 (e.g., more specifically, a tracking system 134), a tracking system 205 (e.g., more specifically, a tracking receiver 210), a tracking receiver 350, or a tracking receiver 450. In some embodiments, a ground station (e.g., more specifically, a tracking system, or a tracking receiver of a tracking system) may perform the described functions by executing a set of instructions for controlling the functional elements of a device. Additionally or alternatively, a ground station may perform aspects of the described functions using dedicated hardware.

[0092] In 705, the method may include receiving a first signal of a first frequency via a first path at a first input of a tracking receiver, and receiving a calibration signal of a second frequency. Operation of 705 may be carried out according to the examples disclosed herein.

[0093] In 710, the method may include receiving a first signal of a first frequency via a second path at a second input of a tracking receiver, and receiving a calibration signal of a second frequency. Operation of 710 may be carried out according to the examples disclosed herein.

[0094] In 715, the method may include outputting a calibration signal to a first coupler coupled to a first path and a second coupler coupled to a second path. Operation of 715 may be carried out according to the examples disclosed herein.

[0095] In 720, the method may include determining a first phase value for a second frequency based at least in part on calibration signals of a second frequency received at a first input and a second input. Operation of 720 may be carried out according to the examples disclosed herein.

[0096] In 725, the method may include determining a second phase value associated with a first frequency from a first phase value, at least in part on a first phase offset between a first frequency and a second frequency, the first phase offset being determined at least in part on a first set of receiver calibration coefficients. The operation of 725 may be carried out according to the examples disclosed herein.

[0097] In 730, the method may include generating a phase correction value for a received first frequency signal, for example, via an antenna, based at least in part on a second phase value. The operation of 730 may be carried out according to the examples disclosed herein.

[0098] Figure 8 shows a flowchart illustrating Method 800, which supports a system and method for calibrating a ground station, as disclosed herein. The operation of Method 800 may be implemented by ground devices, e.g., ground stations 130, 230, 630, or their components, as described herein. For example, the operation of Method 800 may be performed by a ground station transceiver 135 (e.g., more specifically, a tracking system 134), a tracking system 205 (e.g., more specifically, a tracking receiver 210), a tracking receiver 350, or a tracking receiver 450. In some embodiments, a ground station (e.g., more specifically, a tracking system, or a tracking receiver of a tracking system) may perform the described functions by executing a set of instructions for controlling the functional elements of a device. Additionally or alternatively, a ground station may perform aspects of the described functions using dedicated hardware.

[0099] In 805, the method may include outputting calibration signals for each frequency of a frequency set from the calibration output. Operation of 805 may be carried out according to the examples disclosed herein.

[0100] In 810, the method may include receiving output calibration signals at the first and second inputs. Operation of 810 may be carried out according to the examples disclosed herein.

[0101] In 815, the method may include determining a first set of phase values ​​associated with a first receiver of a tracking receiver, the first receiver being coupled to both a first input and a second input. Operation of 815 may be carried out according to the examples disclosed herein.

[0102] In 820, the method may include determining a second set of phase values ​​associated with a second receiver of a tracking receiver, the second receiver being coupled to both the first and second inputs. Operation of 820 may be carried out according to the examples disclosed herein.

[0103] In 825, the method may include generating a first receiver calibration coefficient set based at least in part on a first phase set and a second phase value set. Operation of 825 may be carried out according to the examples disclosed herein.

[0104] These methods illustrate examples of implementations, and it should be noted that the operations and steps may be reconfigured or otherwise modified to allow for other implementations. In some embodiments, embodiments from two or more methods may be combined. For example, an embodiment of each method may include a step or embodiment of another method, or other steps or techniques described herein. In one embodiment, method 800 may be performed (e.g., during the characterization stage), and method 900 may be performed later (e.g., during the calibration stage using a receiver calibration coefficient set).

[0105] The apparatus will be described below. An overview of the embodiments of the apparatus described herein is provided below.

[0106] The following provides an overview of the aspects of this disclosure.

[0107] Embodiment 1: A method for use in a satellite communication system, comprising: receiving a first signal of a first frequency and a calibration signal of a second frequency via a first path at a first input of a tracking receiver; receiving a first signal of a first frequency and a calibration signal of a second frequency via a second path at a second input of the tracking receiver; outputting the calibration signal to a first coupler coupled to the first path and a second coupler coupled to the second path; and applying a small amount of the calibration signal of the second frequency received at the first and second inputs. A method comprising: determining a first phase value for a second frequency based at least partially on; determining a second phase value associated with a first frequency from the first phase value based at least partially on a first phase offset between a first frequency and a second frequency, wherein the first phase offset is determined at least partially on a first set of receiver calibration coefficients; and generating a phase correction value for a received signal of the first frequency based at least partially on the second phase value.

[0108] Embodiment 2: The method according to Embodiment 1, wherein the tracking receiver comprises at least a first receiver for a first signal of a first frequency and a second receiver for a calibration signal of a second frequency, wherein a second phase value associated with the first frequency is determined at least in part on a second phase offset between the first receiver for the first frequency and the second receiver for the first frequency, and the second phase offset is determined at least in part on a first receiver calibration coefficient set.

[0109] Embodiment 3: The method according to Embodiment 2, further comprising determining a second phase offset from a first set-off receiver calibration coefficient based at least in part on gradient, offset, and temperature.

[0110] Embodiment 4: The method according to any one of embodiments 1 to 3, further comprising selecting a second frequency for a calibration output, at least in part on the basis that the second frequency is different from the first frequency.

[0111] Embodiment 5: The method according to any one of embodiments 1 to 4, further comprising identifying a periodic time interval for performing calibration and generating an updated phase correction value for a first signal of a first frequency received according to the periodic time interval.

[0112] Embodiment 6: The method according to any one of embodiments 1 to 5, wherein the tracking feed comprises a set of antennas offset from an antenna configured to receive a first signal of a first frequency, and coupled to a second input via a second path.

[0113] Embodiment 7: The method according to any one of embodiments 1 to 6, wherein the tracking feed comprises a tracking coupler coupled to an antenna and a first path for receiving a first signal of a first frequency, and the tracking coupler is coupled to a second input via a second path.

[0114] Embodiment 8: The method according to any one of embodiments 1 to 7, wherein a first set of receiver calibration coefficients is associated with a first path, a second set of receiver calibration coefficients is associated with a second path, and a third input of a tracking receiver is coupled to an antenna to receive the first signal via the second path.

[0115] Embodiment 9: The method according to Embodiment 8, wherein a first set of receiver calibration coefficients is associated with a first polarization type for a signal received by a tracking receiver via a first path, and a second set of receiver calibration coefficients is associated with a second polarization type for a signal received by a tracking receiver via a second path.

[0116] Embodiment 10: The method according to any one of embodiments 1 to 9, further comprising: outputting calibration signals for each frequency in a frequency set from a calibration output; receiving output calibration signals at a first input and a second input; determining a first set of phase values ​​associated with a first receiver of a tracking receiver, wherein the first receiver is coupled to both the first input and the second input; determining a second set of phase values ​​associated with a second receiver of a tracking receiver, wherein the second receiver is coupled to both the first input and the second input; and generating a first set of receiver calibration coefficients based at least in part on the first set of phase values ​​and the second set of phase values.

[0117] Embodiment 11: The method according to Embodiment 10, wherein generating a first receiver calibration coefficient set based at least in part on a first phase value set and a second phase value set comprises determining a first slope and a first offset for a first line that fits the difference between the first phase value set and the second phase value set as a function of frequency, and determining a second slope and a second offset for a second line that fits the first phase value set as a function of frequency, wherein the receiver calibration coefficient set includes at least a first slope, a first offset, a second slope and a second offset.

[0118] Embodiment 12: An apparatus for use in a satellite communication system, comprising a processor, a memory coupled to the processor, and instructions stored in the memory and executable by the processor for causing the apparatus to perform the method according to any one of Embodiments 1 to 11.

[0119] Embodiment 13: An apparatus for use in a satellite communication system, comprising at least one means for performing the method described in any of Embodiments 1 to 11.

[0120] Embodiment 14: A non-temporary computer-readable medium for storing code for use in a satellite communication system, wherein the code includes instructions that can be executed by a processor to perform the method described in any of Embodiments 1 to 11.

[0121] Embodiment 15: A system for tracking a satellite, comprising: an antenna configured to receive a first signal of a first frequency; a tracking feed; a tracking receiver comprising: a first input coupled to the antenna for receiving the first signal via a first path; a second input coupled to the tracking feed for receiving the first signal via a second path; a calibration output for outputting a calibration signal of a second frequency, coupled to the first path via a first coupler and to the second path via a second coupler; and a calibration component coupled to the first input, the second input, and the calibration output, wherein the calibration component is A system configured to store a first set of receiver calibration coefficients; determine a first phase value for a second frequency based at least in part on calibration signals of a second frequency received at a first input and a second input; determine a second phase value associated with a first frequency from the first phase value based at least in part on a first phase offset between the first frequency and the second frequency, wherein the first phase offset is determined at least in part on the first set of receiver calibration coefficients; and generate a phase correction value for the received first frequency signal based at least in part on the second phase value.

[0122] Embodiment 16: The method according to Embodiment 15, wherein the tracking receiver further comprises at least a first receiver for a first signal of a first frequency and a second receiver for a calibration signal of a second frequency, the calibration component being further configured to determine a second phase value associated with a first frequency, at least in part on a second phase offset between the first receiver for the first frequency and the second receiver for the first frequency, the second phase offset being determined at least in part on a first receiver calibration coefficient set.

[0123] Embodiment 17: The system according to Embodiment 16, wherein the calibration component is configured to determine a second phase offset from a first set-off receiver calibration coefficient, at least in part, based on gradient, offset, and temperature.

[0124] Embodiment 18: The system according to any one of embodiments 15 to 17, further comprising selecting a second frequency for a calibration output, at least in part on the basis that the second frequency is different from the first frequency.

[0125] Embodiment 19: The system according to any one of embodiments 15 to 18, wherein the calibration component is further configured to select a second frequency for a calibration output, at least in part on the basis that the second frequency is different from the first frequency.

[0126] Embodiment 20: The system according to any one of embodiments 15 to 19, wherein the calibration component is further configured to identify a periodic time interval for performing a calibration and to generate an updated phase correction value for a first signal received through an antenna at a first frequency according to the periodic time interval.

[0127] Embodiment 21: The system according to any one of embodiments 15 to 20, comprising a set of antennas, the tracking feed being a set of antennas offset from an antenna configured to receive a first signal of a first frequency, and coupled to a second input via a second path.

[0128] Embodiment 22: The system according to any one of Embodiments 15 to 21, wherein the tracking feed comprises a tracking coupler coupled to an antenna and a first path for receiving a first signal of a first frequency, and the tracking coupler is coupled to a second input via a second path.

[0129] Embodiment 23: The system according to any one of embodiments 15 to 22, wherein a first receiver calibration coefficient set is associated with a first path, a second receiver calibration coefficient set is associated with a third path, and a third input of a tracking receiver is coupled to an antenna to receive the first signal via the third path.

[0130] Embodiment 24: The system according to Embodiment 23, wherein a first set of receiver calibration coefficients is associated with a first polarization type for a signal received by a tracking receiver via a first path, and a second set of receiver calibration coefficients is associated with a second polarization type for a signal received by a tracking receiver via a second path.

[0131] Embodiment 25: A system of any embodiment 15 to 24, further comprising: a first amplifier component located on a first path and coupled to the antenna and a first input of a tracking receiver; and a second amplifier component located on a second path and coupled to the calibration output and a second input.

[0132] Embodiment 26: The system according to Embodiment 25, wherein the first amplifier component comprises a first low-noise block down converter, and the second amplifier component comprises a second low-noise block down converter.

[0133] Embodiment 27: The system according to Embodiment 25, wherein the calibration component is further configured to output calibration signals for each frequency in a frequency set from a calibration output; receive output calibration signals at a first input and a second input; determine a first set of phase values ​​associated with a first receiver of a tracking receiver, wherein the first receiver is coupled to both the first input and the second input; determine a second set of phase values ​​associated with a second receiver of a tracking receiver, wherein the second receiver is coupled to both the first input and the second input; and generate a first set of receiver calibration coefficients based at least in part on the first set of phase values ​​and the second set of phase values.

[0134] Embodiment 28: The system according to Embodiment 27, wherein the calibration component is further configured to determine a first slope and a first offset for a first line that fits the difference between a first phase value set and a second phase value set as a function of frequency, and to determine a second slope and a second offset for a second line that fits the first phase value set as a function of frequency, the receiver calibration coefficient set includes at least a first slope, a first offset, a second slope and a second offset.

[0135] The information and signals described herein can be represented using any of the various different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout this description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0136] Various exemplary blocks and modules described in connection with the disclosure herein may be implemented or run using general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration).

[0137] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions may be stored or transmitted as one or more instructions or codes on a computer-readable medium. Other embodiments and implementations are within the scope of this disclosure and the accompanying claims. For example, due to the nature of the software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. The feature implementing the function may also be physically positioned in various locations, including being distributed so that parts of the function are implemented in different physical locations.

[0138] Computer-readable media include both non-temporary computer storage media and communication media, including any media that facilitate the transfer of computer programs from one location to another. Non-temporary storage media may be any available media accessible by a general-purpose computer or a special-purpose computer. Examples, but not limited to, non-temporary computer-readable media may include RAM, ROM, electrically erasable programmable read-only memory (EEPROM), flash memory, compact disk read-only memory (CDROM) or other optical disk storage devices, magnetic disk storage devices or other magnetic storage devices, or any other non-temporary media that can be used to execute or store desired program code means in the form of instructions or data structures, and that can be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. Any connection is also appropriately referred to as computer-readable media. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless techniques such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless techniques such as infrared, radio, and microwave are included in the definition of media. Disk and disc, as used herein, include CDs, laserdiscs, optical discs, digital multipurpose discs (DVDs), floppy disks, and Blu-ray discs, which typically reproduce data optically using a laser. Combinations of the above are also included within the scope of computer-readable media.

[0139] When used herein, including in the claims, "or" in a list of items (e.g., a list of items preceded by phrases such as "at least one" or "one or more") indicates a comprehensive list, such as the list "at least one A, B, or C" meaning A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, when used herein, the phrase "based on" should not be construed as a reference to a limited set of conditions. For example, an exemplary step described as "based on condition A" may be based on both condition A and condition B without departing from the scope of this disclosure. In other words, when used herein, the phrase "based on" should be construed in the same way as the phrase "at least partially based on."

[0140] In the attached diagram, similar components or features may have the same reference label. Furthermore, various components of the same type may be distinguished by following a reference label with a dash and a second label that distinguishes them from similar components. When only the first reference label is used herein, the description is applicable to any one of the similar components having the same first reference label, regardless of the second reference label or any other subsequent reference labels.

[0141] The descriptions herein, in relation to the accompanying drawings, describe exemplary configurations and do not represent all embodiments that may be practiced or that fall within the scope of the claims. The term “exemplary” as used herein means “serving as an example, illustration, or demonstrative,” and does not imply “preferred” or “advantageous over other embodiments.” Detailed descriptions include specific details for the purpose of providing an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some embodiments, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described embodiments.

[0142] The descriptions herein are provided to enable those skilled in the art to construct or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is given the broadest scope that is consistent with the principles and novel features disclosed herein.

Claims

1. A system (100) for tracking satellites, Antennas (301, 401) configured to receive a first signal of a first frequency, Tracking feeds (360, 460) and Tracking receivers (350, 450), A first input (330, 430) coupled to the antenna to receive the first signal via the first path, A second input (345, 445) coupled to the tracking feed to receive the first signal via a second path, Calibration outputs (340, 440) for outputting a calibration signal at a second frequency, which are coupled to the first path via a first coupler (310, 410) and to the second path via a second coupler (365, 465), A tracking receiver (350, 450) includes the first inputs (330, 430), the second inputs (345, 445), and calibration components (453, 353) coupled to the calibration output, wherein the calibration components (453, 353) are To store the first receiver calibration coefficient set, The first phase value of the second frequency is determined based at least in part on the calibration signal of the second frequency received at the first input (330, 430) and the second input (345, 445), Determining a second phase value associated with the first frequency from the first phase value, at least in part on a first phase offset between the first frequency and the second frequency, wherein the first phase offset is determined at least in part on a first receiver calibration coefficient set. A system (100) is configured to generate a phase correction value for the received first frequency signal, at least in part, based on the second phase value.

2. The tracking receiver (350, 450) further comprises at least a first receiver (351, 451) for the first signal of the first frequency and a second receiver (352, 452) for the calibration signal of the second frequency, The system (100) according to claim 1, wherein the calibration components (353, 453) are further configured to determine the second phase value associated with the first frequency based at least in part on a second phase offset between the first receiver (351, 451) for the first frequency and the second receiver (352, 452) for the first frequency, the second phase offset is determined at least in part on a set of first receiver calibration coefficients.

3. The system (100) according to claim 2, wherein the calibration components (353, 453) are configured to determine the second phase offset from the first receiver calibration coefficient set, at least in part, on gradient, offset, and temperature.

4. The calibration components (353, 453) are The system (100) according to any one of claims 1 to 3, further configured to select the second frequency for the calibration output, at least in part on the fact that the second frequency is different from the first frequency.

5. The calibration components (353, 453) are Identifying periodic time intervals for performing calibration, The system (100) according to any one of claims 1 to 4, further configured to generate updated phase correction values ​​for the first signal received through the antenna at the first frequency according to the periodic time intervals.

6. The system (100) according to any one of claims 1 to 5, wherein the tracking feed comprises a set of antennas (302-a, 302-b, 302-c, 302-d) offset from the antenna (301) configured to receive the first signal of the first frequency, and coupled to the second input (345) via the second path.

7. The system (100) according to any one of claims 1 to 5, wherein the tracking feed (460) comprises a tracking coupler (403) coupled to the antenna (401) and a first path for receiving the first signal of the first frequency, and the tracking coupler (403) is coupled to the second input (445) via the second path.

8. The first receiver calibration coefficient set is associated with the first path, The second receiver calibration coefficient set is associated with the third path. The system (100) according to any one of claims 1 to 7, wherein the third input of the tracking receiver is coupled to the antenna (301, 401) to receive the first signal via the third path.

9. The first set of receiver calibration coefficients is associated with a first polarization type for the signal received by the tracking receiver via the first path, The system (100) according to any one of claim 8, wherein a second set of receiver calibration coefficients is associated with a second polarization type for the signal received by the tracking receiver via the second path.

10. A first amplifier component (320, 420) is located on the first path and is coupled to the first input of the antenna (301, 401) and the tracking receiver (350, 450), The system (100) according to any one of claims 1 to 9, further comprising: a second amplifier component (325, 425) located on the second path and coupled to the calibration output (340, 440) and the second input (345, 445).

11. The first amplifier component (320, 420) includes a first low-noise block-down converter. The system according to claim 10, wherein the second amplifier component (325, 425) includes a second low-noise block down converter.

12. The calibration components (353, 453) are From the calibration outputs (340, 440), calibration signals for each frequency in the frequency set are output. The calibration signal output from the calibration output (340, 440) is received at the first input (330, 430) via the first coupler (310, 410), and then received at the second input (345, 445) via the second coupler (365, 465). Determining a first phase value set associated with the first receiver (351, 451) of the tracking receiver (350, 450), wherein the first receiver (351, 451) is coupled to both the first input (330, 430) and the second input (345, 445). Determining a second set of phase values ​​associated with the second receiver (352, 452) of the tracking receiver (350, 450), wherein the second receiver (352, 452) is coupled to both the first input (330, 430) and the second input (345, 445). The system (100) according to any one of claims 1 to 11, further configured to generate the first receiver calibration coefficient set based at least in part on the first phase value set and the second phase value set.

13. The calibration component is, Determining a first slope and a first offset for a first line that fits the difference between the first phase value set and the second phase value set as a function of frequency, The system is further configured to determine a second slope and a second offset for a second line that fits the first set of phase values ​​as a function of frequency, The system (100) according to claim 12, wherein the receiver calibration coefficient set includes at least the first gradient, the first offset, the second gradient, and the second offset.

14. A method for use in a satellite communication system (100), The first input (330, 430) of the tracking receiver (350, 450) receives a first signal of a first frequency and a calibration signal of a second frequency via a first path. The second input (345, 445) of the tracking receiver (350, 450) receives the first signal of the first frequency and the calibration signal of the second frequency via the second path. The calibration signal is output to the first coupler (310, 410) connected to the first path and the second coupler (365, 465) connected to the second path. Determining a first phase value for the second frequency based at least in part on the calibration signal of the second frequency received at the first input (330, 430) and the second input (345, 445), Determining a second phase value associated with the first frequency from the first phase value, at least in part on a first phase offset between the first frequency and the second frequency, wherein the first phase offset is determined at least in part on a first set of receiver calibration coefficients. A method comprising generating a phase-corrected value of the received first frequency signal based at least in part on the second phase value.

15. The tracking receiver (350, 450) comprises at least a first receiver (351, 451) for the first signal of the first frequency and a second receiver (352, 452) for the calibration signal of the second frequency, The method according to claim 14, wherein the second phase value associated with the first frequency is determined at least in part on a second phase offset between the first receiver (351, 451) for the first frequency and the second receiver (352, 452) for the first frequency, and the second phase offset is determined at least in part on a set of first receiver calibration coefficients.

16. The method according to claim 15, further comprising determining the second phase offset from the first set of receiver calibration coefficients based at least in part on gradient, offset, and temperature.

17. The method according to any one of claims 14 to 16, further comprising selecting the second frequency for a calibration output (340, 440) on at least in part that the second frequency is different from the first frequency.

18. Identifying periodic time intervals for performing calibration, The method according to claim 14, further comprising generating updated phase correction values ​​for the first signal of the first frequency received according to the periodic time interval.

19. The method according to claim 14, wherein the tracking feed (360, 460) is associated with an antenna (301) and configured to receive the first signal of the first frequency, and comprises a set of antennas (302-a, 302-b, 302-c, 302-d) offset from the antenna (301), and coupled to the second input via the second path.

20. The method according to claim 19, wherein the tracking feed comprises a tracking coupler (350, 450) coupled to the antenna (401), and the first path for receiving the first signal of the first frequency, the tracking coupler (350, 450) being coupled to the second input (345, 445) via the second path.

21. The first receiver calibration coefficient set is associated with the first path, A second set of receiver calibration coefficients is associated with a second path. The method according to claim 19, wherein the third input (335, 435) of the tracking receiver is coupled to the antenna to receive the first signal via the second path.

22. The first set of receiver calibration coefficients is associated with a first polarization type for the signals received by the tracking receivers (335, 435) via the first path. The method according to claim 19, wherein a second set of receiver calibration coefficients is associated with a second polarization type for signals received by the tracking receivers (350, 450) via the second path.

23. Outputting calibration signals for each frequency in the frequency set from the calibration output (340, 440), The output calibration signal is received at the first input and the second input, Determining a first phase value set associated with the first receiver of the tracking receiver (350, 450), wherein the first receiver is coupled to both the first input (330, 430) and the second input (345, 445). Determining a second set of phase values ​​associated with the second receiver (352, 452) of the tracking receiver (350, 450), wherein the second receiver (352, 452) is coupled to both the first input (330, 430) and the second input (345, 445). The method according to claim 14, further comprising generating the first receiver calibration coefficient set based at least in part on the first phase value set and the second phase value set.

24. The first receiver calibration coefficient set is generated based at least partially on the first phase value set and the second phase value set. Determining a first slope and a first offset for a first line that fits the difference between the first phase value set and the second phase value set as a function of frequency, This includes determining a second slope and a second offset for a second line that fits the first set of phase values ​​as a function of frequency, The method according to claim 23, wherein the receiver calibration coefficient set includes at least the first gradient, the first offset, the second gradient, and the second offset.

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