Improvements relating to satellite communication terminals

Abstract

The invention relates to a device for determining an orientation and geographical location of an antenna of a satellite communications (SATCOM) terminal. The device is suitable for mounting to the SAT

Description

Field

[0001] The subject matter herein relates generally to the field of satellite communication (SATCOM) terminals and more specifically to devices and methods for determining an orientation and location of an antenna of a SATCOM terminal. Introduction

[0002] Satellite Communication (SATCOM) terminals are used to establish communication links through satellites. Generally, a SATCOM terminal comprises an antenna to transmit and receive signals, modems / amplifiers for modulating / demodulating transmitted and received signals, and a controller for controlling the operation of the SATCOM terminal. SATCOM terminals have the ability to offer mobile communications capability for military, government, non-government, and commercial organisations. Summary

[0003] Owing to the tactical mobility of SATCOM terminals there is a requirement to be able to accurately point an antenna of a SATCOM terminal towards a predetermined satellite, anywhere in the World. Precise alignment is a requirement for successful operation of a SATCOM terminal, particularly with an increasing number of satellites now being deployed in the Space environment resulting in both spatial and signal congestion.

[0004] Furthermore, the tactical advantage of mobile SATCOM terminals is reduced where the terminal itself has high size, weight and power (SWaP) and where deployment and alignment of the SATCOM terminal is a complex and time-consuming process. Often, the alignment of an antenna of a SATCOM terminal is a manual procedure with crude or even no alignment feedback.

[0005] Hence, it is desirable to provide devices and methods for determining an orientation and location of an antenna of a SATCOM terminal that mitigate these issues.

[0006] According to a first aspect, there is provided a device for mounting to a satellite communications (SATCOM) terminal for determining an orientation and geographical location of an antenna of the SATCOM terminal, the device comprising: an accelerometer for providing a first orientation data; a magnetometer for providing a second orientation data; a gyroscope for providing a third orientation data; a global navigation satellite system ‘GNSS’ module for providing a location data; at least one memory; and at least one processor coupled with the at least one memory, wherein the at least one memory comprises instructions which when executed by the at least one processor, cause the at least one processor to: determine the orientation based on the first, second and third orientation data; determine the geographical location based on the location data; and output the determined orientation and geographical location for use by a controller of the SATCOM terminal.

[0007] The device may be mountable to an antenna or antenna head of a SATCOM terminal. The device may therefore when mounted move in orientation and position as the antenna is moved and reorientated. The precise mounting position may vary depending on application. For instance, the device may be mounted to the antenna head of an antenna such that functionally the device moves in position and angle as the antenna is reorientated.

[0008] The device provides a current orientation that is calculated by combining the outputs (the first, second and third orientation data) from the three sensors: the accelerometer, magnetometer; and gyroscope. By fusing these outputs an accurate calculation of, for instance, Magnetic North and Earth’s gravity vector can be achieved providing heading, pitch and roll values for orientation. The GNSS module provides accurate current geographical position. Only a single GNSS module tends to be required owing to the fusion / operation with the other electromechanical sensors (the accelerometer, magnetometer, gyroscope). As discussed herein, the term “GNSS module” may include the GNSS antenna and receiver processing. The combined information (orientation and geographical location) can then be output for use by a SATCOM controller that is providing the interface between the SATCOM terminal and a user. The outputted orientation and geographic location may be used to control alignment of the antenna of the SATCOM terminal directly (i.e., through automated means) or may be used to display alignment information to a user for manual realignment.

[0009] The device tends to simplify in particular the manual pointing and setup of SATCOM terminals by providing ‘live’ and highly accurate feedback of the terminal’s current orientation (also known as ‘look angle’), so that a user can be easily guided towards a desired satellite. This tends to facilitate alignment of a SATCOM terminal anywhere in the World.

[0010] Furthermore, the device tends to be able to be retrofitted to any SATCOM terminal and usable therewith to align respective antennas quickly and accurately.

[0011] As will be discussed herein, the device offers a smaller, lighter and more efficient approach to determining orientation and position of a SATCOM terminal.

[0012] The instructions may cause the at least one processor to determine the orientation by causing the at least one processor to: combine the first orientation data, second orientation data and third orientation data, using a quaternion-based sensor fusion algorithm, wherein the quaternion-based sensor fusion algorithm is optionally a Madgwick algorithm.

[0013] The algorithm tends to ensure that the orientation determined by the device is accurate and drift-free, providing a reliable representation of the device’s three-dimensional orientation. The algorithm fuses the outputs of the accelerometer, magnetometer and gyroscope (9-axes) into a single quaternion output. The Madgwick algorithm is a filter that estimates such an orientation in quaternion space that can run in real-time. The Madgwick algorithm tends to provide a good balance between performance, accuracy and computational efficiency. Furthermore, the Madgwick algorithm tends to be tunable to bias the algorithm to favour absolute accuracy.

[0014] The instructions may cause the at least one processor to determine the orientation by causing the at least one processor to: determine a gravity aligned orientation data from the first orientation data; determine a magnetically aligned orientation data from the second orientation data; and combine, using the quaternion-based sensor fusion algorithm, the gravity aligned orientation data, magnetically aligned orientation data, and third orientation data.

[0015] The gravity aligned orientation data is obtained by filtering and processing the accelerometer readings (first orientation data) to isolate the direction of gravity. Such filtering and processing techniques would be understood by one skilled in the art. In parallel, the magnetometer readings (second orientation data) are processed to estimate the device’s orientation with respect to the Earth’s magnetic field. This allows magnetically aligned orientation data to be determined (i.e., the device’s magnetic heading corresponding to an orientation relative to a Magnetic North reference).

[0016] The device may be designed to prioritize the accelerometer and magnetometer outputs (the first and second orientation data), aligning the orientation closely with gravity and true magnetic North. Prior art solutions are generally biased for smooth motion and hence an accumulation of relative errors can build-up over time. This tends to be mitigated by prioritizing the accelerometer and magnetometer outputs.

[0017] The instructions may cause the at least one processor to determine the orientation by causing the at least one processor to: monitor and correct the determined orientation, using the third orientation data.

[0018] The gyroscope may provide angular rate measurements that can be utilized to monitor changes in the device’s orientation over time. The output of the gyroscope (the third orientation data) tends to be used for interference rejection. The third orientation data tends to be used to detect interference such as the influence of a passing magnetic object on a stationary device. In such example scenarios, the gyroscope’s stable readings tend to help in identifying and disregarding skewed magnetometer readings. Conversely, when the device rotates smoothly when mounted to an antenna of a SATCOM terminal, any non-linear magnetic responses owing to soft iron interference tend to be counteracted by the gyroscope’s consistent readings, again ensuring a smooth motion tracking. Hence an accurate and reliable orientation can be determined.

[0019] The instructions may cause the at least one processor to determine the orientation by causing the at least one processor to: retrieve calibration data stored in the at least one memory, wherein the calibration data comprises one or more of biases, gains and rotations; and apply the calibration data to one or more of the first orientation data, second orientation data and third orientation data.

[0020] Calibration of the device may be performed before deployment and may be a multistage process that results in biases, gains and / or rotations that can be stored in the device’s memory. The biases, gains and / or rotations can be applied to the raw data generated by the accelerometer, magnetometer and / or gyroscope prior to said data being fused / combined to determine the orientation.

[0021] The device may be used primarily as a North referenced attitude sensor and hence the accelerometer and magnetometer accuracies are important for measuring real absolute values. The gyroscope accuracy may be less significant and deployed mainly for interference rejection purposes. Hence the accelerometer and magnetometer may be calibrated and the gyroscope not.

[0022] By calibrating, the device tends to be able to ignore interference from shock, vibration and passing magnetic objects.

[0023] The GNSS module may be configured for providing location data using Global Position System (GPS), Galileo and GLONASS constellations, wherein the instructions cause the at least one processor to determine the geographical location by causing the at least one processor to combine the location data of GPS, Galileo and GLONASS constellations.

[0024] By combining / fusing the location data from GPS, Galileo and GLONASS, the device is able to reject any constellations exhibiting issues or that are subject to jamming. This provides accurate and resilient determination of geographical location.

[0025] In some embodiments the GNSS module may comprise a capacitor means (i.e., a super capacitor) for maintaining GNSS ephemeris data. This enables the ephemeris data to be maintained between power cycles. Ephemeris data can be used to predict the locations of GPS satellite constellations, allowing relatively quicker acquisition of satellites (also referred to as “Time to First Fix”). Hence, maintaining the ephemeris data between power cycles tends to allow the GNSS module to resolve a geographical location more quickly, following a power cycle.

[0026] The housing may be mountable to the SATCOM terminal, the housing containing the accelerometer, magnetometer, gyroscope, GNSS sensor, the at least one memory and the at least one processor, wherein the housing optionally comprises a main chassis and lid bonded together.

[0027] The housing tends to be sealed providing environmental protection for the device components and may be waterproof to a rating of IP68. The housing may comprise peripherals, such as LEDs indicating power and unit status to a user. The LEDs may be provided setback into light pipes extending through the housing, the light-pipes being filled with clear silicone, for instance, to maintain ingress protection.

[0028] The housing may be formed from PA-12 Nylon. Such a material is radio transparent allowing functional operation of the device components to be maintained when inside the housing.

[0029] The housing may have an exterior length, exterior width, and exterior depth that are respectively less than or equal to 100mm, less than or equal to 70mm and less than or equal to 40mm. More preferably the exterior length, exterior width, and exterior depth are respectively less than or equal to 80mm, less than or equal to 60mm and less than or equal to 30mm. Even more preferably the exterior length, exterior width and exterior depth are equal to or less than 70mm, 53mm and 23mm respectively. The device can be manufactured to have a relatively small size which enables the device to be deployed with SATCOM terminals with minimal footprint and hence minimal impact on the SWaP of the SATCOM terminal as a whole.

[0030] The housing may comprise a plurality of bolt-holes for mounting the housing to the antenna of the SATCOM terminal. The precise number of bolt-holes may vary depending on application. For instance, 1, 2, 3 or 4 bolt-holes may be used. The bolt-holes may extend through the housing at corners of the housing to mitigate the impact on the internal dimensions of the housing. Screws, bolts or other fastening means may extend through the bolt-holes to fix the device to a SATCOM terminal.

[0031] The GNSS module may be arranged on a first printed circuit board; the accelerometer, magnetometer and gyroscope, the at least one memory and the at least one processor, may be arranged on a second printed circuit board; and the first and second printed circuit boards may be connected using a ribbon cable. The GNSS module may have its own ground plane.

[0032] Providing the GNSS module on a separate circuit board to the other sensors provides flexibility of the deployment of the GNSS module. For instance, a GNSS antenna of the GNSS module can be angled within the housing to maximise visibility of GNSS satellites. Furthermore, the design of the device is future-proofed to allow other GNSS module configurations to be deployed — the first printed circuit can be removed and reconfigured without substantially impacting the components on the second printed circuit board.

[0033] The GNSS antenna of the GNSS module may be angled relative to a plane of the housing. This tends to allow for greater visibility of GNSS satellites. The GNSS antenna may be angled such that is points away from the boresight of the antenna of the SATCOM terminal, when the device is mounted to the SATCOM terminal, such that interference can be mitigated.

[0034] The housing may comprise at least one of: one or more pegs for locating the first and second printed circuit boards; and one or more clips for retaining the first and second printed circuit boards. This tends to allow the circuit boards to be located, aligned and retained securely within the housing.

[0035] The accelerometer, magnetometer and gyroscope may comprise respective three-axis micro-electromechanical sensors. This tends to allow the SWaP of the device to be improved.

[0036] The device may further comprise a temperature sensor for providing a temperature data to the at least one processor for a thermal calibration of the device.

[0037] The device may comprise a single interface connector for connecting the device to a SATCOM controller of the SATCOM terminal. A M8 connector may be used to provide power, data connectivity and analogue input / output. The use of a single interface connector tends to allow for the device to be made more compact, further improving the SWaP.

[0038] The instructions may cause the at least one processor to output the determined orientation and geographical location by causing the at least one processor to output the determined orientation and geographical location as a data message comprising: the geographical location; and the determined orientation as a Quaternion or Euler angle.

[0039] The geographical location and determined orientation may be provided to a controller of a SATCOM terminal. The determined orientation output as a Quaternion or Euler angle can be transformed to correct for the mounting orientation of the device on the SATCOM terminal. Furthermore, the geographic location combined with the determined orientation can be used to calculate accurate antenna pointing angles, RF transmission timings and also to obtain magnetic declination data which can be used to adjust azimuth angles.

[0040] The data message may further comprise a time the data message is sent and / or a temperature when the data message is sent.

[0041] The data message may further comprise a checksum for enabling a data integrity check of the data message to be completed when the data message is received by, for instance, a controller of a SATCOM terminal.

[0042] The data message may be output at an output frequency i.e., at a rate of 5Hz. This allows geographic location and orientation information to be updated regularly, improving SATCOM alignment.

[0043] The data message may comprise a comma separated sentence, wherein the first element thereof describes the message type. Supplementary metadata may also be output, optionally at a lower rate.

[0044] According to a second aspect, there is provided a controller for a SATCOM terminal comprising: at least one memory; and at least one processor; wherein the at least one memory comprises instructions which when executed by the at least one processor cause the at least one processor to: receive a determined orientation and geographical location of an antenna of the SATCOM terminal from the device of the first aspect; and generate, based on at least the determined orientation and geographical location, a steering information for reorientating a boresight of the antenna of the SATCOM terminal towards a predetermined satellite.

[0045] The controller may be used to control and manage one or more aspects of the SATCOM terminal. This may include antenna alignment and pointing, power, signal routing, antenna detection (frequency band, cable connections), etc. The controller may provide an interface between SATCOM equipment and a user.

[0046] The controller is configured to utilize the determined orientation and geographic location from one or more devices of the first aspect to determine alignment of an antenna of the SATCOM terminal. In this regard, the controller may be configured to query the device for the determined orientation and geographic location, or to read the determined orientation and geographic location from the device. More specifically, the controller may be configured to read a data message output from the device which may require reading the data message at an output frequency of the device, and / or parsing the data message.

[0047] The controller may provide power to the device of the first aspect. Alternatively, the device of the first aspect may have its own power source (batteries, capacitors, port for receiving power, etc.).

[0048] The determined orientation and geographic location are used by the controller to ascertain how the SATCOM terminal (in particular the antenna thereof) needs to be steered or realigned in order to achieve communication with a predetermined satellite. The instructions may further cause the at least one processor to output the steering information as a control signal for: controlling a means for reorientating the antenna; and / or controlling a display unit to display one or more user instructions for reorientating the antenna. A SATCOM terminal may be provided with automated apparatus such as an azimuth / elevation or equatorial motorised mount for orientating an antenna of the SATCOM terminal. In such examples, the control signal may directly control such apparatus. The SATCOM terminal and associated antenna may alternatively be manually adjustable. In such examples the control signal may comprise information that controls a display unit (of the controller or separate thereto) to display one or more instructions indicating to a user how to reorientate the antenna of the SATCOM terminal to achieve satellite alignment.

[0049] The instructions may further cause the at least one processor to: query the device for an identifier of an antenna of the SATCOM terminal, the identifier being preconfigured in the device; and reconfigure, based on the identifier, the controller for use with the antenna.

[0050] The device of the first aspect may be pre-programmed with an identifier for the antenna of the SATCOM terminal with which the device is to be deployed. This identifier may be stored in the at least one memory of the device. The controller, by querying the device for the identifier, can itself identify the antenna of the SATCOM terminal and hence reconfigure itself for use with the device and SATCOM terminal. The identifier may be referred to herein as a ‘Head ID’. The controller may query the device during bootup of the controller.

[0051] The instructions may further cause the at least one processor to: retrieve from the at least one memory, based on the identifier, one or more transforms for transforming the determined orientation to a boresight of the antenna of the SATCOM terminal; and apply the one or more transforms to the determined orientation.

[0052] The transforms may be stored in a read-only database of the controller. The transforms describe the rotations required between the device of the first aspect and the RF boresight of the antenna, taking account of the mounting orientation of the device. The mounting orientation may be predetermined for a given antenna of a SATCOM terminal. Hence by obtaining the identifier, the antenna of the SATCOM terminal and the mounting configuration of the device of the first aspect can be inferred.

[0053] According to a third aspect, there is provided an apparatus for determining an orientation and geographical location of an antenna of the SATCOM terminal, comprising: at least one controller according to the second aspect; and at least one device according to the first aspect.

[0054] According to a fourth aspect, there is provided a SATCOM terminal comprising: an antenna for communicating with at least one predetermined satellite; the controller of the second aspect; and at least one device according to the first aspect; wherein the at least one device is mounted to the SATCOM terminal and is communicatively connected with the controller, such that a determined orientation and geographical location from the device can be used by the controller to generate steering information for reorientating the antenna towards the at least one predetermined satellite.

[0055] The at least one device may be communicatively connected with the controller via an interconnecting cable, the interconnecting cable passing through an electronic module of the antenna, the electronic module comprising a plurality of switches for determining a configuration of the antenna. The plurality of switches may set a resistor divider network according to the size of the SATCOM terminal antenna (i.e., the reflector).

[0056] According to a fifth aspect, there is provided a computer-implemented method for determining an orientation and geographical location of an antenna of a SATCOM terminal, the method comprising: receiving first, second and third orientation data respectively from an accelerometer, magnetometer and gyroscope mounted to the SATCOM terminal; determining the orientation based on the first, second and third orientation data; receiving a location data from a GNSS module mounted to the SATCOM terminal; determining the geographical location based on the location data; and outputting the determined orientation and geographical location for use by a controller of the SATCOM terminal.

[0057] The determining the orientation may comprise: combining the first orientation data, second orientation data and third orientation data, using a quaternion-based sensor fusion algorithm, wherein the quaternion-based sensor fusion algorithm is optionally a Madgwick algorithm.

[0058] The determining the orientation may comprise: determining a gravity aligned orientation data from the first orientation data; determining a magnetically aligned orientation data from the second orientation data; and combining, using the quaternion-based sensor fusion algorithm, the gravity aligned orientation data, magnetically aligned orientation data, and third orientation data.

[0059] The determining the orientation may comprise monitoring and correcting the determined orientation, using the third orientation data.

[0060] The determining the orientation may comprise: retrieving calibration data, wherein the calibration data comprises one or more of biases, gains and rotations; and applying the calibration data to one or more of the first orientation data, second orientation data and third orientation data.

[0061] The determining the geographical location may comprise combining the location data of GPS, Galileo and GLONASS constellations.

[0062] The outputting the determined orientation and geographical location may comprise outputting as a data message comprising: the geographical location; and the determined orientation as a Quaternion or Euler angle.

[0063] According to a sixth aspect, there is provided a computer program comprising instructions which when executed by a processor of a device for determining an orientation and location of an antenna of a SATCOM terminal, causes the processor to perform the steps of the fifth aspect.

[0064] According to a seventh aspect, there is provided a non-transitory computer-readable storage medium comprising the computer program of the sixth aspect.

[0065] It will be appreciated that particular features of different aspects share the technical effects and benefits of corresponding features of other aspects of the invention.

[0066] It will also be appreciated that the use of the terms “first” and “second”, and the like, are merely intended to help distinguish between similar features and are not intended to indicate a relative importance of one feature over another, unless otherwise specified.

[0067] Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, and the claims and / or the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and all features of any embodiment can be combined in anyway and / or combination, unless such features are incompatible. Brief description of the drawings

[0068] Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 shows an example of a SATCOM terminal; Figure 2 shows an example of a system architecture for a device for mounting to a SATCOM terminal; Figure 3A shows an example, in top view, of a housing for a device for mounting to a SATCOM terminal; Figure 3B shows in side-view, the housing of Figure 3A; Figure 3C shows in further side-view, the housing of Figure 3A; Figure 3D shows in perspective view, the housing of Figure 3A; Figure 4 shows an example of printed circuit boards held within a housing of a device for mounting to a SATCOM terminal; Figure 5 shows an example of a calibration carousel for calibrating a device, the device for mounting to a SATCOM terminal; Figure 6 shows an example of the application of calibration data to raw sensor data; and Figure 7 shows an example of a computer-implemented method for determining an orientation and location of an antenna of a SATCOM terminal. Detailed description

[0069] Figure 1 shows an example of a SATCOM terminal 100.

[0070] The SATCOM terminal 100 comprises an antenna 110. The antenna 110 is a dishreflector type antenna having a boresight ‘O’.

[0071] The SATCOM terminal 100 comprises a plurality of legs 120 providing stability for the antenna 110. The legs 120 comprise respective leg adjustors 122, 124, 126 that can be manually adjusted to stabilize and position the antenna 110. The antenna 110 is mounted to an antenna head 130 that can be manually rotated in azimuth and elevation relative to legs 120.

[0072] A controller 140 for the SATCOM terminal 100 is also shown. The controller 140 controls one or more aspects of the operation of the SATCOM terminal 100. The controller 140 manages and generates instructions for manually aligning the boresight O of antenna 110 with a predetermined satellite. The control 140 also provides power management, signal routing, and detection of antenna 110. The controller 140 provides a visual interface for a user of SATCOM terminal 100. The controller 140 may be modem and terminal agnostic to allow for a ‘plug and play’ solution with different antenna types. The controller 140 is ruggedized to provide environmental and ingress protection, for instance to IP65 standards. The controller 140 comprises at least one memory and at least one processor coupled with the at least one memory. The at least one memory comprises instructions for execution by the at least one processor.

[0073] In-use, a user of the SATCOM terminal 100 manually aligns the boresight O of antenna 110 to a predetermined satellite using instructions presented on a visual interface of controller 140. The manual adjustment requires the user to adjust leg adjustors 122, 124, 126 and antenna head 130. The manual alignment can be difficult to achieve quickly and efficiently without accurate and timely feedback from the controller 140. Some antennas 110 may provide a coarse feedback to controller 140 which is not sufficient as satellite space becomes more and more congested. Furthermore, in many cases, no direct feedback is provided from antennas 110 at all.

[0074] In response to these requirements, the inventors have provided a device that can be mounted to a SATCOM terminal, more specifically mounted to the movable antenna or antenna head of a SATCOM terminal. The device tends to establish a mechanism for providing accurate and reliable orientation and location information to a controller of the SATCOM terminal.

[0075] Figure 2 shows an example of a system architecture 200 for a device for mounting to an antenna of a SATCOM terminal.

[0076] The system architecture 200 comprises a microprocessor 210. The microprocessor 210 interfaces with all sensors of the device of the first aspect. The microprocessor 210 hosts the customized calibration and fusion algorithms for positioning as described herein. The microprocessor also hosts the command line interface for communications (i.e., universal asynchronous receiver / transmitter (UART) communications). The microprocessor 210 may be an STM32 ARM® Cortex® M4 32-bit RISC microprocessor.

[0077] The system architecture 200 also comprises a plurality of electromechanical sensors 220. The electromechanical sensors 220 comprise an accelerometer 222, a magnetometer 224 and a gyroscope 226. The accelerometer 222, magnetometer 224 and gyroscope 226 provide respective first orientation data, second orientation data and third orientation data to the microprocessor 210.

[0078] The accelerometer 222 provides high accuracy accelerometer sensing in an integrated package that is temperature stable. The accelerometer 222 is software configurable and provides a digital interface to microprocessor 210. The accelerometer 222 provides gravity referencing and may be an Analogue Devices AD XL (micro-electromechanical system (MEMS)) accelerometer.

[0079] The magnetometer 224 comprises three discrete sensor coils mounted orthogonally to one another providing high resolution and temperature stable magnetic sensing. The coils are excited and fused by a supplementary controller that provides a digital interface to the microprocessor 210. The magnetometer 224 provides magnetic North referencing and may be a TNI RM3100 Magneto Inductive Sensor. The supplementary controller may be a TNI MagI2C controller.

[0080] The gyroscope 226 is a fully integrated software configurable package. The gyroscope 226 provides rotation referencing and may be a TDK IAM 3-Axis gyroscope.

[0081] The system 200 also comprises a GNSS module 230 comprising a GNSS antenna 234 and receiver 232. The GNSS module 230 provides global positioning and timing. The GNSS module 230 may be a UBLOX M8 GNSS module.

[0082] The GNSS module 230 fuses positioning data from GPS, Galileo and GLONASS constellations to provide accurate and resilient positioning data to the microprocessor 210. The GNSS module 230 also comprises a super capacitor (not visible) that is used to maintain GPS ephemeris data between power cycles.

[0083] The system 200 also comprises a temperature sensor 240 communicating with microprocessor 210. The temperature sensor 240 is used for thermal calibration. The temperature sensor 240 provides temperature data to the microprocessor 210 over a digital interface. The temperature sensor 240 may be a Microchip MCP9843 temperature sensor.

[0084] The system 200 also comprises a head-detect module 250 communicating with microprocessor 210. The head-detect module 250 provides terminal-type orientation detection that is sensed via an analogue input. A divider circuit is used to determine unique configurations allowing terminal-type identification. The head-detect module 250 is shown as communicating an identifier for an antenna externally (for instance to a controller of a SATCOM terminal).

[0085] The system 200 also comprises a bootloader 260 communicating with microprocessor 210. The bootloader 260 is a discrete microprocessor that is used to provide over the air firmware updates to the microprocessor 210. A data packet can be detected by the bootloader 260 to set the microprocessor 210 into programming mode. The bootloader 260 may comprise a PIC18 microprocessor.

[0086] The system 200 also comprises an RS422 driver 270 communicating with microprocessor 210, bootloader 260 and externally to the system 200. RS422 serial lines may be provided by a Texas Instruments THVD RS485 transceiver which interfaces to the TTL UART interface of the microprocessor 210. The RS422 driver 270 may be implemented as standard for RS422 but can be configured as addressable RS485.

[0087] The system 200 also comprises non-volatile memory 280 (i.e., non-volatile randomaccess memory (NVRAM)) communicating with microprocessor 210. The memory 280 may be flash storage provided by, for instance, an ISSIIS25 16MB memory chip. This is used to store and retrieve sensor calibration data and non-volatile system configuration settings. The microprocessor 210 itself may comprise associated memory.

[0088] In general, the microprocessor 210 determines an orientation based on the first, second and third orientation data received from accelerometer 222, magnetometer 224 and gyroscope 226. The microprocessor 210 determines a geographical location based on location data from GNSS module 230. The microprocessor 210 outputs the determined orientation and geographical location using the RS422 driver 270 for use by a controller of the SATCOM terminal. Calibration information from NVRAM 280 may be utilized in the determination of the orientation as will be later discussed.

[0089] Figure 3A shows an example, in top view, of a housing 300 for a device for mounting to a SATCOM terminal. The housing 300 is formed from RF transparent PA-12 Nylon and comprises a main chassis 320 and a lid (not visible).

[0090] The housing 300 contains the accelerometer, magnetometer, gyroscope, at least one memory and at least one processor. The housing 300 is sealed providing ingress protection to IP68 standard.

[0091] Evident from Figure 3A is a single M8 connector 330 providing connection between the interior and exterior of the housing 300. The single M8 connector 330 is used to provide power, RS422 data connectivity and analogue input / output (for instance for antenna terminal orientation detection).

[0092] The housing 300 has a substantially rectangular cross section having exterior dimensions of 70mm and 50-53mm. Evident from Figure 3A is that housing 300 comprises four bolt-holes 342, 344, 346, 348. The bolt-holes 342, 344, 346, 348 are arranged in the four corners of the housing 300. The bolt-holes 342, 344 and 346, 348 are separated in a first dimension by 38mm. The bolt-holes 342, 346 and 344, 348 are separated in a second dimension by 58mm. The bolt-holes 342, 344, 346, 348 have a partially tapered inner diameter of 8m through to approximately 4mm.

[0093] The main chassis 320 comprises a raised and angled section 322 which will be discussed further with respect to Figure 3B.

[0094] Figure 3B shows in side view, the housing 300 of Figure 3A. The main chassis 320 and the lid 310 of the housing 300 are now visible. The depth of the housing 300 is approximately 23mm. The single connector 330 is also visible.

[0095] The main chassis 320 of the housing 300 comprises the raised angled section 322. The raised angled section 322 houses the GNSS antenna of the GNSS module and is angled to allow for greater visibility of GNSS satellite constellations.

[0096] Figure 3C shows in a different side view, the housing 300 of Figure 3A. The main chassis 320 and lid 310 of housing 300 are visible, with the protruding raised angled section 322. In this side-view, recessed parts 352, 354 are shown adjacent bolt-holes 342, 344. The recessed parts 352, 354 ensure bolts positioned in bolt-holes 342, 344 are recessed into the housing 300 and do not protrude therefrom. This ensures the housing 300 can maintain a compact form factor when mounted to a SATCOM terminal.

[0097] Figure 3D shows in perspective view, the housing 300 of Figure 3A. The main chassis 320 is shown attached to lid 310. The main chassis 320 and lid 310 may be sealed together with suitable adhesive or bonding material such as silicone.

[0098] Figure 4 shows an example of printed circuit boards 460 held within a housing 400 of a device for mounting to a SATCOM terminal. A main chassis 420 of the housing 400 is shown with lid removed. The main chassis 420 is shown as forming a tray-like structure allowing circuit boards 460 to be recessed into the main chassis 420. The circuit boards 460 substantially conform to the interior of the main chassis 420, minimizing translational movement. Furthermore, the circuit boards 460 are mounted on one or more pegs that position the circuit board 460 within main chassis 420.

[0099] A first printed circuit board (not visible) comprising the GNSS module is first positioned within the main chassis 420. Above the first printed circuit, a second printed circuit board 464 is arranged. The accelerometer, magnetometer and gyroscope, the at least one memory and the at least one processor, are arranged on a second printed circuit board 464. The second printed circuit board 464 is connected to the first printed circuit board using a ribbon cable 466.

[0100] A single M8 connector 430 is shown extending from circuit boards 460 through main chassis 420 and connecting to cable 470. The cable 470 may be connected to a controller for a SATCOM terminal.

[0101] As will be appreciated by one skilled in the art, the printed circuit boards 460 may comprise programming points for the various microprocessors, test points for production, LEDs and solder points (for instance for an external IP68 connector loom).

[0102] The device disclosed herein may be calibrated prior to use and prior to mounting to a SATCOM terminal. The calibration procedure may be a multi-step procedure that results in calibration data that can be stored in NVRAM such as the NVRAM 280 of Figure 2. This calibration data may include biases, gains and rotations that can be applied to raw orientation data from the accelerometer, magnetometer and gyroscope, before any data fusion occurs. Since the device disclosed herein is primarily used as a North references attitude sensor, the accelerometer and magnetometer sensor accuracies are important for measuring real absolute values of orientation. The gyroscope accuracy may be less significant and hence used to detect interference or unexpected external events only. In this respect, the accelerometer and magnetometer may be calibrated and the gyroscope not. The calibration procedure broadly follows a three-step process involving: calibrating bias and offset for each sensor axis; calibrating individual sensor orientation; calibrating overall device orientation. The procedures for calibrating the accelerometer and magnetometer will now be discussed with regard to Figure 5 which shows an example of a calibration carousel 500 for calibrating a device for mounting to an antenna of a SATCOM terminal.

[0103] The accelerometer calibration will first be described. The calibration is performed using a two-axis motorized carousel 500. The carousel 500 has an octagonal cross-section and is substantially tubular, defining eight exterior faces. A housing 400 of a device according to the first aspect is shown mounted to one of the exterior faces, the housing containing the components of the device. The carousel 500 can be rotated about an axis ‘A’ that is concentric to carousel 500. The rotation is controlled by a first motor. The carousel 500 can also be rotated about a further axis ‘B’ that is orthogonal to axis A. The rotation is controlled by a second motor. Up to eight devices of the first aspect can be calibrated simultaneously using carousel 500 by mounting a device to each exterior face of the carousel 500.

[0104] The carousel 500 is sequentially driven using the first and second motors to predetermined positions. More specifically, the carousel 500 is driven to 42 equally-spaced points in x, y and z axes. Raw accelerometer data is collected for each coordinate.

[0105] The 42 3D coordinates are fitted to an ellipsoid using a least squares optimization. The parameters of the ellipsoid are used to transform the coordinates into a unit sphere of radius 1g (gravitational acceleration) that is centered at an origin (i.e., at 0, 0, 0). These transforms are then saved into the device of the first aspect (i.e., into NVRAM 280 of Figure 2).

[0106] The transformed data is then combined with the actual gravity vector values for each of the 42 equally-spaced points. Singular value decomposition is then used to find the best fit rotation to align the accelerometer with the housing of the device of the first aspect. This rotation becomes a zero-reference and is also saved into the device (i.e., into NVRAM 280 of Figure 2). The spatial transforms of the ellipsoids discussed herein may be stored as a set of eigenvectors referred to herein as ‘evecs’.

[0107] The magnetometer calibration will now be described. The magnetometer calibration accounts for hard and soft iron distortions as well as sensor alignment. This calibration may be performed when a device of the first aspect is mounted to a SATCOM terminal to ensure any magnetic interference from fasteners or active components can be calibrated out.

[0108] Initially, raw magnetometer data is collected for x, y and x axes. This is typically a guided manual procedures wherein the device of the first aspect is physically rotated in all orientations to collect raw data across an even distribution of x, y, z points. A graphical user interface may be used to show the data collection and analysis in real-time.

[0109] Once the raw data has been collected it is fitted to an ellipsoid using a method similar to that discussed herein for calibrating the accelerometer. The difference for the magnetometer calibration is that the ellipsoid being fitted has a target radius of 420uT (micro-Torr). The transformations are saved into the device of the first aspect (i.e., into the NVRAM 280 of Figure 2). The spatial transforms of the ellipsoid may be stored as a set of eigenvectors herein referred to as ‘evecs’.

[0110] The raw magnetometer data combined with the calibrated accelerometer data is then used in a derivative-free optimization algorithm to find a best fit alignment between the measured magnetometer flux vectors and the calibrated gravity vector. This best fit rotation is also saved into the device (i.e., into the NVRAM 280 of Figure 2).

[0111] On startup of a device according to the first aspect, the calibration data is retrieved from memory. This may involve retrieving the calibration data from NVRAM 280 of Figure 2. The calibration data is then applied to each of the accelerometer 222, magnetometer 224, and gyroscope 226 of Figure 2. Figure 6 shows an example 600 of the application of calibration data to raw sensor data.

[0112] The example 600 shows the application of calibration data respectively to the first orientation data of the accelerometer 610, the second orientation data of the magnetometer 620 and the third orientation data of the gyroscope 630.

[0113] For the calibration of the accelerometer 610, initially the raw accelerometer data 611 is received. A bias 612 is then added to the raw data 611. Next, an evecs 613 is applied. A scale factor 614 is then applied. Then an evecs_T 615 is applied. The output of this procedure is used as part of the zero_rotation 640. The parameter ‘evecs’ refers to the eigenvectors that are used to describe the spatial transforms of the ellipsoid previously discussed herein with respect to the calibration procedure and Figure 5. The parameter ‘evecs_T’ refers to the transpose or inverse of the parameter ‘evecs’.

[0114] For the calibration of the magnetometer 620, initially the raw magnetometer data 621 is received. A bias 622 is added to the raw data 621. Next, an evecs 623 is applied. A scale factor 624 is then applied. Then an evecs_T 625 is applied. Finally, a rotation 626 is applied. The output of this procedure is used as part of the zero_rotation 640. The parameter ‘evecs’ refers to the eigenvectors that are used to describe the spatial transforms of the ellipsoid previously discussed herein with respect to the calibration procedure and Figure 5. The parameter ‘evecs_T’ refers to the transpose or inverse of the parameter ‘evecs’.

[0115] For the gyroscope 630 the raw gyroscope data 631 is used without any biases, gains or rotations applied. The output of this procedure is used as part of the zero_rotation 640.

[0116] The zero_rotation 640 may be output as raw data 670 or may be fused 650 to provide a determined orientation that can be output as a data message 660 for use by a controller of a SATCOM terminal.

[0117] The fusion 650 is provided by a Madgwick filter that fuses the calibrated accelerometer data (calibrated first orientation data), the calibrated magnetometer data (calibrated second orientation data), and the raw gyroscope data (third orientation data) into a single quaternion output. The calibrated data from the accelerometer, magnetometer and the gyroscope data is fed to the Madgwick filter at 100Hz.

[0118] More specifically the fusion 650 involves estimating the gravitational component of the calibrated accelerometer data and estimating, from the calibrated magnetometer data, an orientation with respect to Earth’s magnetic field (the magnetic heading of the device). The gyroscope data provides angular rate measurements that can be used to monitor changes in orientation over time. The Madgwick filter combines the gravity-aligned and magnetic-aligned data, with the gyroscope data, in the fusion 650.

[0119] The data message 660 is output at a rate of 5Hz with additional metadata output at a slower rate. The data message 660 takes the form of a custom NMEA sentence that includes a checksum for data integrity. The custom NMEA sentence may include date / time data, latitude and longitude, height (for instance in metres above mean sea level), the XYZW components of a quaternion orientation, a temperature (in degrees Celsius) and the checksum. As an alternative to the quaternion orientation a Euler angle may be output in the data message 660 as a magnetic heading, a pitch (elevation) and roll. It will be appreciated that in the fusion 650 the GNSS module location data may be used to determine the latitude and longitude output in data message 660.

[0120] The calibration procedure discussed herein can mitigate the susceptibility of the accelerometer, magnetometer and gyroscope to various external factors. In particular, where the sensors are micro-electromechanical sensors, they can be particularly susceptible to temperature. By following the calibration procedures discussed herein, the device of the first aspect tends to be functional and accurate across a temperature range from -40°C to +60°C. The fusion 650 then enables the device to ignore interference from external events such as shock, vibration or passing magnetic objects.

[0121] Figure 7 shows an example of a computer-implemented method 700 for determining an orientation and geographical location of an antenna of a SATCOM terminal.

[0122] A first step 710 comprises receiving first, second and third orientation data respectively from an accelerometer, magnetometer and gyroscope mounted to the antenna of the SATCOM terminal.

[0123] A second step 720 comprises determining the orientation based on the first, second and third orientation data.

[0124] A third step 730 comprises receiving a location data from a GNSS module mounted to the antenna of the SATCOM terminal.

[0125] A fourth step 740 comprises determining the geographical location based on the location data.

[0126] A fifth step 750 comprises outputting the determined orientation and geographical location for use by a controller of the SATCOM terminal.

[0127] As referred to herein a SATCOM terminal may include any SATCOM terminal. Specific examples of SATCOM terminals include SWARM®, Hornet, CONNECT100T and MANTA manufactured by Paradigm.

[0128] As referred to herein the controller of a SATCOM terminal may include the Paradigm Interface Module manufactured by Paradigm.

[0129] Whilst the embodiments described herein may refer to a single device of the first aspect deployed with a SATCOM terminal, this is not intended to be limiting. A plurality of devices may be deployed with a given a SATCOM terminal if the application requires.

[0130] Whilst the embodiments described herein may refer to specific mounting positions of a device to an antenna of a SATCOM terminal, this is not intended to be limiting. The device of the present disclosure is a positioning and orientation sensor that provides feedback on the position and orientation of an antenna of a SATCOM terminal. Hence mounting positions that allow a change in antenna boresight orientation to be detected by the device, are within scope of the present disclosure.

[0131] Reference throughout this specification to an example of a particular method or apparatus, or similar language, means that a particular feature, structure, or characteristic described in connection with that example is included in at least one implementation of the method and apparatus described herein. The terms “including”, “comprising”, “having”, and variations thereof, mean “including but not limited to”, unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms “a”, “an”, and “the” also refer to “one or more”, unless expressly specified otherwise.

[0132] As used herein, a list with a conjunction of “and / or” includes any single item in the list or a combination of items in the list. For example, a list of A, B and / or C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C. As used herein, a list using the terminology “one or more of’ includes any single item in the list or a combination of items in the list. For example, one or more of A, B and C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C. As used herein, a list using the terminology “one of’ includes one, and only one, of any single item in the list. For example, “one of A, B and C” includes only A, only B or only C and excludes combinations of A, B and C. As used herein, “a member selected from the group consisting of A, B, and C” includes one and only one of A, B, or C, and excludes combinations of A, B, and C.” As used herein, “a member selected from the group consisting of A, B, and C and combinations thereof’ includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C.

[0133] Aspects of the disclosed method and apparatus are described with reference to schematic flowchart diagrams and / or schematic block diagrams of methods, apparatuses, systems, and program products. It will be understood that each block of the schematic flowchart diagrams and / or schematic block diagrams, and combinations of blocks in the schematic flowchart diagrams and / or schematic block diagrams, can be implemented by code. This code may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the schematic flowchart diagrams and / or schematic block diagrams.

[0134] The schematic flowchart diagrams and / or schematic block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods, and program products. In this regard, each block in the schematic flowchart diagrams and / or schematic block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions of the code for implementing the specified logical function(s).

[0135] It will be appreciated that numerical values recited herein are merely intended to help illustrate the working of the invention and may vary depending on the requirements of a given power transmission network, component thereof, or power transmission application.

[0136] The listing or discussion of apparently prior-published documents or apparently prior-published information in this specification should not necessarily be taken as an acknowledgement that the document or information is part of the state of the art or is common general knowledge.

[0137] Preferences and options for a given aspect, feature or parameter of the invention should, unless the context indicates otherwise, be regarded as having been disclosed in combination with any and all preferences and options for all other aspects, features and parameters of the invention.

[0138] The disclosure herein provides a highly accurate orientation and positioning device that aids the fast and accurate pointing of satellite antennas towards their desired satellite. This tends to be achieved by sending very accurate live feedback of the SATCOM terminal’s current orientation or ‘look angles’ such that a user of the SATCOM terminal can be easily guided. At the core of the device is a microprocessor that is programmed to fuse orientation and positioning data from an accelerometer, magnetometer, gyroscope and GNSS module. 01 08 25

Claims

1. A device for mounting to a manual-point satellite communications ‘SATCOM’ terminal for determining an absolute orientation and geographical location of an antenna of5 the manual-point SATCOM terminal, the device comprising:an accelerometer for providing a first orientation data;a magnetometer for providing a second orientation data;a gyroscope for providing a third orientation data;a global navigation satellite system ‘GNSS’ module for providing a location data;10 at least one memory; andat least one processor coupled with the at least one memory, wherein the at least one memory comprises instructions which when executed by the at least one processor, cause the at least one processor to:retrieve calibration data stored in the at least one memory, wherein the calibration data 15 comprises one or more of biases, gains and rotations;apply the calibration data to the first orientation data and the second orientation data;combine, using a quatemion-based sensor fusion algorithm, the calibrated first orientation data, calibrated second orientation data and the third orientation data, to determine the absolute orientation, wherein the quatemion-based sensor fusion algorithm comprises a20 Madgwick algorithm configured to prioritise the calibrated first orientation data and the calibrated second orientation data for determination of the absolute orientation and to use the third orientation data for detecting and rejecting interference;determine the geographical location based on the location data; andoutput the determined absolute orientation and geographical location for use by a 25 controller of the manual-point SATCOM terminal.

2. The device of claim 1, wherein the instructions cause the at least one processor to determine the absolute orientation by causing the at least one processor to:determine a gravity aligned orientation data from the calibrated first orientation data;30 determine a magnetically aligned orientation data from the calibrated secondorientation data; andcombine, using the quatemion-based sensor fusion algorithm, the gravity aligned orientation data, magnetically aligned orientation data, and third orientation data.01 08 253. The device of any preceding claim, wherein the instructions cause the at least one processor to determine the absolute orientation by causing the at least one processor to:monitor and correct the determined absolute orientation, using the third orientation data.

54. The device of any preceding claim, wherein the GNSS module is configured for providing location data using Global Position System ‘GPS’, Galileo and GLONASS constellations, wherein the instructions cause the at least one processor to determine the geographical location by causing the at least one processor to:10 combine the location data of GPS, Galileo and GLONASS constellations.

5. The device of any preceding claim, further comprising a housing mountable to the manual-point SATCOM terminal, the housing containing the accelerometer, magnetometer, gyroscope, GNSS module, the at least one memory and the at least one processor, wherein the 15 housing optionally comprises a main chassis and lid bonded together.

6. The device of claim 5, wherein the housing is formed from PA-12 Nylon.

7. The device of any one of claims 5-6, wherein the housing has an exterior length,20 exterior width, and exterior depth less than or equal to 100mm, less than or equal to 70mmand less than or equal to 40mm respectively.

8. The device of any one of claims 5-7, wherein the housing comprises a plurality of bolt-holes for mounting the housing to the manual-point SATCOM terminal.

259. The device of any one of claims 5-8, wherein:the GNSS module is arranged on a first printed circuit board;the accelerometer, magnetometer and gyroscope, the at least one memory and the at least one processor, are arranged on a second printed circuit board; and30 the first and second printed circuit boards are connected using a ribbon cable.

10. The device of claim 9, wherein a GNSS antenna of the GNSS module is angled relative to a plane of the housing.01 08 2511. The device of any one of claims 9-10, wherein the housing comprises at least one of: one or more pegs for locating the first and second printed circuit boards; and one or more clips for retaining the first and second printed circuit boards.5 12. The device of any preceding claim, wherein the accelerometer, magnetometer andgyroscope comprise respective three-axis micro-electromechanical sensors.

13. The device of any preceding claim, wherein the device further comprises a temperature sensor for providing a temperature data to the at least one processor for a thermal calibration 10 of the device.

14. The device of any preceding claim, wherein the device comprises a single interface connector for connecting the device to a manual-point SATCOM controller of the manualpoint SATCOM terminal.1515. The device of any preceding claim, wherein the instructions cause the at least one processor to output the determined absolute orientation and geographical location by causing the at least one processor to output the determined absolute orientation and geographical location as a data message comprising:20 the geographical location; andthe determined absolute orientation as a Quaternion or Euler angle.

16. A controller for a manual-point SATCOM terminal comprising:at least one memory; and25 at least one processor;wherein the at least one memory comprises instructions which when executed by the at least one processor cause the at least one processor to:receive a determined absolute orientation and geographical location of an antenna of the manual-point SATCOM terminal from the device of any preceding claim;30 generate, based on the determined absolute orientation and geographical location, asteering information for manually reorientating a boresight of the antenna of the manual-point SATCOM terminal towards a predetermined satellite.01 08 2517. The controller of claim 16, wherein the instructions further cause the at least one processor to output the steering information as a control signal for:controlling a display unit to display one or more user instructions for manually reorientating the antenna.

518. The controller of any one of claims 16-17, wherein the instructions further cause the at least one processor to:query the device for an identifier of an antenna of the manual-point SATCOM terminal, the identifier being preconfigured in the device; and10 reconfigure, based on the identifier, the controller for use with the antenna.

19. The controller of claim 18, wherein the instructions further cause the at least one processor to:retrieve from the at least one memory, based on the identifier, one or more transforms 15 for transforming the determined absolute orientation to a boresight of the antenna of the manual-point SATCOM terminal; andapply the one or more transforms to the determined absolute orientation.

20. Apparatus for determining an absolute orientation and geographical location of an20 antenna of a manual-point SATCOM terminal, comprising:at least one controller according to any one of claims 16-19; andat least one device according to any one of claims 1-15.

21. A manual-point SATCOM terminal comprising:25 an antenna for communicating with at least one predetermined satellite;the controller of any one of claims 16-19; andat least one device according to any one of claims 1-15;wherein the at least one device is mounted to the antenna and is communicatively connected with the controller, such that a determined absolute orientation and geographical 30 location from the device can be used by the controller to generate steering information for manually reorientating the antenna towards the at least one predetermined satellite.

22. The manual-point SATCOM terminal of claim 21, wherein the at least one device is communicatively connected with the controller via an interconnecting cable, the01 08 25interconnecting cable passing through an electronic module of the antenna, the electronic module comprising a plurality of switches for determining a configuration of the antenna.

23. A computer-implemented method for determining an absolute orientation and 5 geographical location of an antenna of a manual-point SATCOM terminal, the method comprising:receiving first, second and third orientation data respectively from an accelerometer, magnetometer and gyroscope mounted to the manual-point SATCOM terminal;retrieving calibration data from a memory, wherein the calibration data comprises one 10 or more of biases, gains and rotations; andapplying the calibration data to the first orientation data and the second orientation data;combining, using a quaternion-based sensor fusion algorithm, the calibrated first orientation data, calibrated second orientation data and the third orientation data, to determine 15 the absolute orientation, wherein the quaternion-based sensor fusion algorithm comprises a Madgwick algorithm, wherein the combining comprises:prioritising, in the Madgwick algorithm, the calibrated first orientation data and the calibrated second orientation data for determining the absolute orientation; andusing, in the Madgwick algorithm, the third orientation data for detecting and 20 rejecting interference;receiving a location data from a GNSS module mounted to the manual-point SATCOM terminal;determining the geographical location based on the location data; andoutputting the determined absolute orientation and geographical location for use by a 25 controller of the manual-point SATCOM terminal.

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