Method and apparatus for processing radio signals

Abstract

A system is disclosed that includes a mobile platform (113), an antenna (102) configured to receive a signal (14) from a remote source (2) in a first direction, a mobile mechanism (114) mounted to the platform, where the antenna is mounted to the mobile mechanism, the mobile mechanism configured to move the antenna relative to the platform, and a controller (108) configured to generate a local signal, where the local signal is transmitted to the mobile platform. The method includes receiving a signal from a remote source, determining a motion component of the antenna in a first direction, correlating a local signal with the received signal to provide a correlated signal, and motion compensating at least one of the local signal, the signal from the remote source, and the correlated signal based on the determined motion of the antenna in the first direction.

Description

Technical Field

[0001] The present invention relates to a positioning or communication system. More particularly, the present invention relates to a positioning or communication system capable of using motion compensation to improve signal reception. Background Art

[0002] Some positioning systems use the motion between the positioning device and a reference source to determine a more accurate position of the positioning device. A method called supercorrelation is described in commonly assigned patent publication number WO 2017 / 163042. TM The present invention relates to a technique of the present invention, which is incorporated herein by reference in its entirety, that performs correlation using motion compensation relative to the motion of the receiver. Motion compensated signal correlation is particularly useful in indoor or outdoor environments where buildings can block and reflect signals from a remote reference source, making the signal more difficult to detect.

[0003] It is desirable to be able to perform motion compensation even when the positioning device is stationary or the motion between the positioning device and the reference source is relatively small. In addition, for a given positioning device, it is desirable to be able to perform motion compensation on positioning signals received from a wider range of angles at once. Motion compensation can also be used to process radio signals in addition to positioning signals. Similarly, it would be advantageous to be able to perform motion compensation to process radio signals when the motion between the source and the receiver is relatively small.

[0004] The present invention aims to address these needs. Summary of the invention

[0005] According to aspects of the present invention, there is provided an apparatus configured to process radio signals, comprising: a mobile platform; an antenna configured to receive a signal from a remote source in a first direction; a mobile mechanism mounted on the platform, wherein the antenna is mounted on the mobile mechanism, and the mobile mechanism is configured to move the antenna relative to the platform; and a controller configured to: generate a local signal; determine a motion component of the antenna along the first direction; provide a correlated signal by correlating the local signal with a received signal; and perform motion compensation on at least one of the local signal, the received signal, and the correlated signal based on the determined motion of the antenna in the first direction.

[0006] Performing motion compensation requires at least some relative motion between the remote source and the antenna along a first direction. The direction may be a straight line between the remote source and the antenna, whether or not blocked by an intervening object, or it may be another direction of interest. A movement mechanism of an embodiment of the present invention provides movement of the antenna in the first direction. This allows the device to perform motion compensation even when there is little or no relative motion between the platform and the remote source in the first direction. In one example scenario, the platform may be stationary. In another scenario, the platform may move in a direction substantially perpendicular to the first direction. In both cases, the movement of the antenna in the first direction provided by the movement mechanism allows motion compensation to be performed despite the absence of movement of the platform in the first direction. In this way, motion compensation may be used in a wider range of situations.

[0007] The device may be a positioning system, and the signal may be a positioning signal from a remote positioning source, such as a GNSS satellite or a ground source. In other embodiments, the device may be designed as a transceiver of a communication signal, such as a WiFi signal, a Bluetooth signal, a cellular signal, etc.

[0008] A mobile platform may also be described as a platform mounted to a body including any type of motion equipment, such as wheels for ground travel or propellers for flight. A mobile platform may be provided in or on any mobile device. A mobile device may be configured to carry or move position while performing motion compensation. For example, a mobile device may include one or more sensors that are capable of determining the composite motion of an antenna.

[0009] In some specific examples, the platform can be provided in a mobile computing device, such as a smartphone or tablet, or in a vehicle, any of which can also be configured as a positioning device. For example, the movement of the platform itself caused by the movement of the device providing the platform can also be used to perform motion compensation in the case where the movement of the first direction and the platform are not perpendicular. In this scenario, motion compensation is performed based on the composite or combined movement of the antenna in the first direction caused by the movement of the platform and the moving mechanism. Thus, the platform can be moving or stationary, and the movement of the antenna can be caused by the platform movement and the moving mechanism.

[0010] The moving mechanism can be configured to move the antenna linearly or nonlinearly relative to the platform. For an antenna moving along a fixed straight path, there are ambiguities in the Doppler measurements arriving from off-axis directions. The only way to resolve these ambiguities is to ensure that the path is not a straight line. Nonlinear motion in 2D (ideally 3D) ensures that different directions around the platform can be uniquely distinguished by their Doppler profiles. It is advantageous to keep the antenna in motion even when the platform is stationary. Therefore, nonlinear motion generated by the moving mechanism can provide better results. However, using a moving mechanism to generate linear motion of the antenna still enables motion compensation to be performed in a wider range of situations.

[0011] There may be more than one antenna on the platform or mobile mechanism. The apparatus may include a first antenna mounted on the mobile mechanism, configured to receive a first type of signal; and a second antenna mounted on the mobile mechanism, configured to receive a second type of signal. For example, a GNSS receiver may use separate antennas for L1 and L5 frequencies. Alternatively, more than one antenna may be assigned to each frequency in use.

[0012] The platform may include a substrate or any other suitable structure on which the moving mechanism may be mounted. In one example, the platform may be an internal substrate or housing of a device or positioning device on which various electronic components of the positioning device are mounted.

[0013] In one example, the remote source is a GNSS (Global Navigation Satellite System) satellite and the positioning system is a GNSS system. The remote source, alternatively referred to as a positioning or reference source, can operate as part of any navigation system known in the art. In general, the positioning system can include any combination of satellite sources, ground sources, or other types of reference sources.

[0014] The local signal may be a copy of a received signal, or a pseudo-random number sequence from a GNSS satellite, or similar well-known content such as a sync word broadcast in a communication channel.

[0015] Motion compensation can be applied using techniques known in the art. For example, motion compensation can be applied to one or more of the following: a received signal, a local signal, or a correlated signal generated by correlating the received signal with the local signal. Similarly, the correlation step can be performed using known correlation techniques in GNSS or other positioning or communication systems.

[0016] The step of providing motion compensation may include: generating a phasor sequence, the phasor sequence including one or more phasors indicating amplitude and / or phase changes introduced into the received signal due to the determined movement of the antenna in the first direction, each phasor including an amplitude and / or a phase angle; and combining the phasor sequence with the at least one of the local signal, the received signal and the correlation signal.

[0017] The phasor sequence includes one or more phasors indicating the amplitude and / or phase changes introduced into the received signal due to the determined movement of the antenna. Each phasor includes at least one of the amplitude and phase angle describing the determined movement of the antenna in the corresponding direction. Typically, the phasor sequence is derived from the determined movement of the antenna over time. For example, each phasor in the phasor sequence may indicate the determined movement of the antenna during a specific time interval. Thus, the resulting phasor sequence indicates (e.g., corresponds to) the determined movement of the antenna during a time period consisting of the individual time intervals. The phasor sequence may reflect the detailed movement of the antenna over time. For example, multiple phasors within the phasor sequence may reflect the movement of the antenna when it is moved by a moving mechanism.

[0018] In one embodiment, the moving mechanism is configured to periodically move the antenna relative to the platform in one, two, or three spatial dimensions. In this way, the moving mechanism can continuously move the antenna along a given path. This can enable motion compensation to be performed at any time using periodic motion. In addition, moving mechanisms that are easy to implement typically utilize some form of periodic motion.

[0019] In one embodiment, the movement mechanism is configured to provide a substantially circular motion of the antenna relative to the platform. In this way, the angular sensitivity of the antenna can be improved. In addition, it has been found that motion compensation is more effective when there is non-linear and non-lateral motion between the antenna and the remote source. Therefore, providing continuous and variable non-linear motion improves the effectiveness of motion compensation. In other embodiments, the movement mechanism can provide other types of motion, such as linear, circular, elliptical, reciprocating, random, jittery or oscillating motion.

[0020] In one embodiment, the moving mechanism comprises a turntable on which the antenna is mounted. The turntable may be a particularly simple implementation of the moving mechanism, thereby reducing the cost of implementing the moving mechanism. The turntable may be driven by a motor or any other means.

[0021] The turntable or any other device providing non-linear motion may be configured to move the antenna at a rate such that the antenna moves through at least 1 / 4 of the wavelength of the incident radiation during the coherent integration time of the correlation process.

[0022] In other embodiments, other movement mechanisms may be provided, such as, but not limited to, sliding, vibrating, oscillating, shaking, rotating, vibrating, or oscillating.

[0023] In one embodiment, the apparatus comprises a motion sensor configured to measure motion of the platform, wherein the controller is configured to determine the motion of the platform based on measurements performed by the motion sensor.

[0024] The controller may also be configured to instruct the movement mechanism to move the antenna and perform motion compensation in response to determining that the platform is moving below a threshold speed in at least a first direction. In this way, the positioning system can be more energy efficient by operating the movement mechanism only when it is necessary to perform motion compensation in the first direction. In some examples, the controller may determine the component of motion of the platform in the first direction before instructing the movement mechanism to move the antenna. In other examples, the controller may determine that the platform is moving below a threshold speed in any direction before instructing the movement mechanism to move the antenna. In another example, the antenna permanently undergoes its own linear or nonlinear motion regardless of the platform motion.

[0025] The motion sensor may include one or more of any type of motion sensing components, such as an inertial or gyroscope sensor configured to determine acceleration, or a magnetometer configured to determine orientation. The motion sensor may be co-located with an antenna to determine the motion of the antenna. For example, the motion sensor may be co-located with an antenna in a moving mechanism.

[0026] In other examples, the motion sensor may be located elsewhere, such as fixed to the platform or in a fixed position relative to the platform. In this case, the resulting motion of the antenna may be determined or calculated by combining the measured motion of the platform with the measured motion of the antenna relative to the platform. In one example, the sensing element may be co-located with the antenna, and the motion sensor may track the movement of the sensing element. Alternatively, the motion of the antenna due to the mobile mechanism may be calculated based on the measured motion of the platform and the predictable movement of the mobile mechanism. Determining the specific component of the motion along the direction of the remote source may be performed using any suitable technique known in the art.

[0027] In another example, there is a motion sensor mounted on the platform and a separate motion sensor co-located with the antenna.

[0028] Based on a set of previous positioning calculations, the controller can assume that the platform is moving in a particular direction at a particular speed. For example, when the platform is incorporated into an apparatus that moves along a long, straight road at a steady speed, the controller can assume or determine the platform's measurements rather than using direct measurements from the motion sensors.

[0029] In other embodiments, the movement mechanism is configured to continuously move the antenna regardless of whether the controller determines that the platform is moving or stationary. This can avoid performing additional measurements and calculations to determine whether the movement mechanism needs to be operated, which may be more efficient in some scenarios.

[0030] In some embodiments, the platform is disposed in or on a vehicle. The platform may be mounted on a wheeled vehicle body. In one example, the platform may be disposed on the roof of the vehicle, which may avoid attenuation of the received positioning signal by the vehicle body or roof. The mobile mechanism may be positioned relative to a set of wheels of the vehicle so that the mobile mechanism can move the antenna in a plane substantially perpendicular to the set of wheels. In this way, the movement of the platform may provide antenna movement in one dimension, while the mobile mechanism may provide antenna movement in a vertical direction, in which the platform itself cannot move. For example, this is particularly advantageous for a platform moving in an urban environment, in which signals are reflected from high-rise buildings on both sides of the direction of travel. Movement of the antenna perpendicular to the direction of travel of the platform enables the system to distinguish signals reflected from buildings on both sides of the street.

[0031] In some embodiments, the platform is provided in any mobile device or mobile computing device, such as a smartphone or laptop. The platform, antenna and movement mechanism may be provided as internal components of the mobile device.

[0032] In some embodiments, it may be desirable to eliminate the effects of phase wrap-up or wrap-down caused by a determined rotation of the antenna, as is known in the art.

[0033] The movement mechanism may be configured to move the antenna in one, two or three dimensions. In such two or three dimensions, this increases the flexibility of the movement mechanism and allows motion compensation to be performed on signals received from a wider range of angles for a given orientation of the platform. The movement mechanism may be any type of movement mechanism configured to generate movement of the antenna along one, two or three dimensions or axes.

[0034] In an embodiment, the device may include a plurality of moving mechanisms and a plurality of antennas mounted to the plurality of moving mechanisms, wherein each of the plurality of moving mechanisms is configured to move a corresponding antenna of the plurality of antennas relative to the platform. In other words, the device may include a first and a second moving mechanism, and the first antenna and the second antenna are mounted on the first and the second moving mechanisms, respectively.

[0035] Each antenna can receive a corresponding signal that can be processed by the controller using motion compensation, which is achieved by the movement of each antenna relative to the platform caused by the corresponding mobile mechanism. The platform can have two or more mobile mechanisms, each carrying one or more antennas. The mobile mechanisms can be configured to move independently of each other in orthogonal directions, thereby providing 2D motion. Three mobile mechanisms that orthogonally move the antennas can provide 3D motion that can be used to perform motion compensation in any direction.

[0036] In an embodiment, the mobile mechanism includes another antenna, or in other words, may include a first antenna and a second antenna. The mobile mechanism may be configured to move the second antenna relative to the platform so that the controller can perform motion compensation on the signal received at the second antenna. The first and second antennas may be configured to receive different radio frequencies. In this way, the device can improve detection of several different frequency bands in a compact arrangement. More than two antennas may be provided on a single mobile mechanism, each antenna being configured to detect radio signals of different frequency bands.

[0037] According to one aspect of the present invention, a method for processing a radio signal is provided, which can be performed in a positioning system, comprising: providing a local signal; providing an antenna movably mounted to a mobile platform; receiving a signal from a remote source at the antenna along a first direction; moving the antenna relative to the platform; determining the movement of the antenna; correlating the local signal with the received signal to provide a correlated signal; and performing motion compensation on at least one of the local signal, the received signal and the correlated signal based on the determined movement of the antenna in the first direction.

[0038] According to one aspect of the present invention, a non-volatile computer-readable medium storing executable instructions is provided, which, when executed by a processor, causes the processor to perform the following steps: providing a local signal; moving an antenna movably mounted to a mobile platform relative to the platform, wherein the antenna receives a signal from a remote source in a first direction; determining movement of the antenna; correlating the local signal with the received signal to provide a correlated signal; and motion compensating at least one of the local signal, the received signal, and the correlated signal based on the determined movement of the antenna in the first direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0040] Figure 1 is a schematic diagram of a positioning system according to an embodiment of the present invention;

[0041] Figure 2 is a schematic diagram of a control system of a positioning device in a positioning system according to an embodiment of the present invention;

[0042] Figure 3 is a schematic diagram of a portion of a positioning system according to an embodiment of the present invention;

[0043] Figure 4 is a schematic diagram of a portion of a positioning system according to an embodiment of the present invention;

[0044] Figure 5A is a schematic flow chart of a method for performing positioning calculation according to an embodiment of the present invention; and

[0045] Figure 5B According to an embodiment of the present invention Figure 5A Continuation of the method that performs positioning calculations. DETAILED DESCRIPTION

[0046] Figure 1 The diagram shows, by way of example, an environment in which the method and positioning system of the present invention can be used to provide a positioning solution. Figure 2 is a schematic diagram of a positioning device 100 and its control system.

[0047] Reference Figure 1 and Figure 2 , the positioning system 1 includes a positioning device 100, which includes an antenna 102 configured to receive signals from remote reference sources. In this example, the positioning device 100 of the user 10 receives radio signals from remote reference sources including a first satellite 2, a second satellite 4, and a remote ground source 6 via the antenna 102. A tall building 12 bisects the line of sight from the positioning device 100 to the second satellite 2 and the ground source 6. The building 12 attenuates the signals from the first satellite 2 and the ground source 6, making the signals weaker, thereby making it more difficult for the positioning device 100 to obtain an accurate position measurement. The same building 12 can also provide a path for reflected signals from the second satellite 4 to the antenna 102.

[0048] like Figure 2 As shown, the example positioning device 100 includes an antenna 102 , a receiver 104 connected to the antenna 102 , a local oscillator 106 , a controller 108 , a memory 110 , a motion sensor 112 , and a turntable 114 .

[0049] The receiver 104 is configured to process signals received by the antenna 102. The receiver 104 may include any suitable electronic components, such as an amplifier or an analog-to-digital converter.

[0050] The local oscillator 106 is configured to provide timing signals for various applications in the positioning device 100, including generating local signals. The local oscillator 106 can be simple and low-cost, and in one example can include a quartz oscillator.

[0051] The controller 108 is configured to control the operation of the electronic components of the positioning device 100, including Figure 2 The components shown and other components in the positioning device 100. In this example, the controller 108 includes a single processor 109, which operates multiple modules described further below, which are configured to perform specific functions. In other embodiments, the modules can be provided separately with different associated processors, or can be provided across the network in a distributed manner.

[0052] The memory 110 may include a non-transitory computer-readable medium, such as a combination of random access and read-only memory units, configured to store executable instructions 111 of various modules of the controller 108. The memory 110 may also store data 113 for implementing the various modules and instructions 111. The instructions 111 may be executed on the processor 109 to perform the method 500 described further below and other operations of the positioning system 1 described herein.

[0053] The motion sensor 112 is configured to determine the motion of the antenna 102, such as velocity and acceleration in a particular direction. The motion sensor 112 may include a plurality of separate motion and / or orientation sensors, such as an inertial sensor, a gyroscope sensor, or a magnetometer.

[0054] The turntable 114 includes a circular base 115 and a motor (not shown) configured to drive the base 115 to continuously rotate when directed by the controller 108. The antenna 102 is mounted on the base 115 so that when the base 115 is rotated by the motor, the antenna 102 follows a substantially circular path. In other example embodiments, the turntable 114 may include other suitable components, such as a non-circular base or other means of driving the base.

[0055] In this example, the motion sensor 112 is co-located with the antenna 102 in the base 115. Thus, the motion sensor 112 can detect the movement of the antenna 102 caused by the rotation of the turntable 114 as well as the movement of the platform 113.

[0056] Alternatively, the motion sensor 112 may be located elsewhere to determine the motion of the positioning device 100. In this case, the individual aspects of the motion of the antenna 102 caused by the turntable 114 may be determined based on a formula for predictable motion generated by the turntable 114. Alternatively, the motion of the antenna 102 may be determined by an additional motion or rotation sensor, such as a tachometer. In this case, the composite motion of the antenna 102 may be calculated based on the measurements from the motion sensor 112 and the additional motion sensor, which is used to determine the motion of the positioning device 100.

[0057] In this example, the positioning device 100 is a smartphone, and the antenna 102 and the turntable 114 are housed in the smartphone. However, for the purpose of illustration, the turntable 114 and the antenna 102 are shown in FIG. Figure 2 1 is shown as being located outside of the positioning device 100. In other examples, the positioning device 100 can be configured as a laptop, a vehicle, or any other type of portable device.

[0058] The controller 108 includes a plurality of modules, including a reference source selector 116, a local signal generator 118, a correlator 120, a motion determination module 122, a motion compensation module 124, and a positioning calculator 126. Figure 5A and 5B The functions of these modules of the controller 108 are further described. These modules can be hardware, software or a combination thereof. In one embodiment, one or more modules can be implemented by the processor 109 of the controller 108 executing software instructions 111 stored in the memory 110.

[0059] Figure 3 A schematic diagram showing parts of the positioning system 1 in an example usage scenario is shown. Figure 3 The lower left corner of shows the axis lines, with the Y axis extending into the page.

[0060] The positioning device 100 further includes a platform 113 fixed to the positioning device 100. The turntable 114 is mounted on the platform 113, such as Figure 3 As shown, the base 115 can be rotated relative to the platform 113 when driven by a motor. In this example, the turntable 114 and the platform 113 are combined in a housing (not shown) of the positioning device 100.

[0061] exist Figure 3 In the example of FIG. 1 , the positioning device 100 is stationary relative to the earth, which may occur when the user 10 holds the positioning device 100 and remains stationary. The first satellite 2 is oriented and moved relative to the positioning device so that there is no relative motion or a small relative motion between the platform 113 and the first remote source 2 along their shared line of sight.

[0062] like Figure 1As shown, the building 12 blocks the positioning signal 14 received from the first satellite 2 along the line of sight, thereby attenuating the positioning signal 14 and making it more difficult to detect compared to the reflected signal from the first satellite 2. Typically, using known positioning systems, it would be desirable to perform motion compensation, but this is not possible due to the lack of line of sight motion. Performing motion compensation increases the gain of the line of sight signal compared to the non-line of sight signal. This can detect very weak line of sight signals. In other cases, it allows the receiver 104 to lock onto the line of sight signal rather than the reflected signal, which would produce a less accurate pseudorange. However, known positioning systems would require the positioning device 100 to move in the line of sight direction of the first satellite 2 or an equivalent movement of the platform 113 on which the antenna 102 is mounted in the line of sight direction of the first satellite 2 in order to perform motion compensation.

[0063] To solve this problem, the controller 108 is configured to instruct the turntable 114 to rotate so that the antenna 102 moves along the line of sight of the first satellite 2, such as Figure 3 This allows motion compensation to be performed by the controller 108 even though there is not sufficient relative motion between the platform 113 and the first satellite 2 in the line of sight direction to perform motion compensation.

[0064] Figure 4 A schematic diagram showing parts of the positioning system 1 in an alternative example usage scenario is shown. Figure 4 The lower left corner of shows the axis lines, with the Y axis extending into the page.

[0065] In this example use, the positioning device 100 and the platform 113 and antenna 102 move in the positive Y direction, as shown by arrow C. The second satellite 4 is positioned farther away in the positive Z and Y directions, while the first satellite 2 is positioned farther away in the positive Z and X directions and moves substantially parallel to the Y axis, as shown by arrow C. Figure 3 as shown in the example.

[0066] Typically, using a known positioning system, in this case, motion compensation can only be performed on the positioning signal 16 received from the second satellite 4 based on the movement of the platform 113 in the Y direction. However, the turntable 114 can move the antenna 102 so as to produce a movement in the X direction, as shown by arrow B, so that motion compensation can be performed on the signal 14 received from the first satellite 2. This enables the positioning device 100 to determine the positioning range with the first satellite 2 and the second satellite 4. In this way, the turntable 114 increases the angular range in which the signal can be received, and the signal can be detected more effectively using motion compensation. In other words, the angular sensitivity of the antenna 102 is increased using the movement of the antenna 102 relative to the platform 113.

[0067] In more detail, each axis along which the antenna 102 is moving relative to the reference source creates two "sensitivity cones" in the sky (one cone in each direction along the axis, each cone emanating from the antenna 102). Each cone is centered on the axis of movement. Motion compensation allows for increased gain of very weak line-of-sight signals from remote sources near the axis of the cone, but motion compensation is less effective in increasing the gain of line-of-sight signals from remote sources located further away from the axis of movement in the sky or on the horizon. Performing motion compensation for remote sources perpendicular to the axis of movement will not allow the positioning system 1 to increase the gain of weak line-of-sight positioning signals.

[0068] In this example, movement C of platform 113 produces a first cone of sensitivity along the Y axis, while rotation B of turntable 114 may produce a second cone of sensitivity along the X axis.

[0069] As the base 115 rotates to move the antenna 102 along a circular path, a second cone of sensitivity created by the rotation B of the antenna 102 sweeps across the sky. Thus, motion compensation can be performed on positioning signals received from any direction, except for remote sources directly overhead. Therefore, rotational motion is particularly preferred. However, it has also been found that motion compensation is more effective when based on non-linear motion, which is also provided by rotational motion.

[0070] The above embodiments are described for positioning devices and positioning signals received from satellites or other positioning sources. However, motion compensation can also be used to more efficiently process radio signals in other systems (such as communication channels). In this case, it is also advantageous to be able to perform motion compensation between the wireless power source and the receiver in a wider range of motion scenarios. It should be understood that the positioning device 100, positioning system 1 and method 500 of the present invention described herein can also be applied to other types of systems using radio signals.

[0071] Figure 5A and 5B An example method 500 for determining the position of a positioning device 100 using a positioning system 1 according to the present invention is shown.

[0072] In step 502, the reference source selector 116 selects a particular reference source from which to receive the positioning signal. The reference source selector 116 may select any suitable available reference source. In this example, the reference source selector 116 selects the first satellite 2, which transmits the positioning signal 14 along the line of sight to the antenna 102. Due to the attenuation of the high-rise building 12 intersecting the line of sight from the first satellite 2 to the antenna 102, the positioning signal 14 is received at the antenna 102 with poor signal strength. Therefore, in order to improve the detection sensitivity, the positioning signal 14 must be processed using motion compensation.

[0073] When the turntable 114 is selectively rather than continuously operated, steps S504 to S508 may be optionally performed to determine when to operate the turntable 114. Therefore, in steps S504 to S508, the turntable 114 is stationary, and thus the antenna 102 is stationary relative to the platform 113.

[0074] In step S504, the motion determination module 122 determines the motion of the antenna 102. The motion determination module 122 can determine the motion of the antenna 102 using data provided by the motion sensor 112, which may include multiple measurements from different component motion and / or orientation sensors. Specifically, the motion determination module 122 determines the motion along the line of sight to the currently selected positioning source (in this case, the first satellite 2). The approximate position of the first satellite 2 and the approximate position of the positioning device 100 can be used to determine the line of sight direction. Conversely, this can be used to calculate the relative motion between the antenna 102 and the first satellite 2. The approximate position and direction of motion of the first satellite 2 can be stored locally in the data 113 of the lookup table of the memory 110, or can be retrieved from the satellite ephemeris or online source, as is well known in the art.

[0075] The motion of antenna 102 may be measured directly using motion sensor 112, as just described. Alternatively, the motion may be assumed or inferred based on previous measurements or recent positioning calculations from motion sensor 112. For example, if it has been calculated or measured that platform 113 moves at a fixed speed in a straight direction, such as when driving or on a train, the motion of antenna 102 may be assumed based on the calculations. In some cases, this may be simpler or less computationally intensive than performing measurements.

[0076] At step S506, motion determination module 122 optionally determines that platform 113 is moving below a threshold speed in the direction of the line of sight of first satellite 2. Therefore, controller 108 concludes that motion compensation cannot be performed using only the motion of platform 113. Alternatively, motion determination module 122 may determine that platform 113 is moving below a threshold speed in any direction, which may be simpler and less computationally intensive.

[0077] In response, at step S508, controller 108 instructs turntable 114 to move, thereby producing non-linear motion of antenna 102 relative to platform 113. This produces sufficient line-of-sight motion between antenna 102 and first satellite 2 to enable motion compensation to be performed even when the platform is stationary.

[0078] Alternatively, the turntable 114 may be configured to rotate continuously while the positioning apparatus 100 is operating, in which case steps S504 , S506 , and S508 are not required.

[0079] The turntable 114 may be configured to rotate at a particular rotation rate. In some examples, the controller 108 may instruct the turntable to change the rotation rate according to the relative orientation of the platform 113 and the first satellite 2 to maximize the effectiveness of motion compensation. Similarly, other devices that provide rotational motion of the antenna 102 may be configured to rotate or change the rotation speed in the same manner.

[0080] At step S510 , the antenna 102 receives the positioning signal 14 from the first satellite 2 .

[0081] At step S512, the motion determination module 122 determines the motion of the antenna 102. The motion sensor 112 is co-located with the antenna 102, and thus detects the resulting motion of the antenna 102 due to the motion of the platform 113 and the turntable 114. In an alternative embodiment, the motion sensor 112 may be located elsewhere to measure the motion of the platform 113, and one or more additional sensors may be provided to measure the speed and position of the antenna 102 relative to the platform 113. In another example, the motion generated by the turntable 114 may be characterized by one or more formulas stored in the memory 110, which may be used to infer the speed and direction of the antenna 102 when receiving the positioning signal 14.

[0082] In any case, the motion determination module 122 performs calculations to determine the motion of the antenna 102 along the line of sight. This line of sight motion is used to perform motion compensation in subsequent steps. If it is determined at step S506 that the platform 113 is stationary, the motion of the antenna 102 includes only the circular motion caused by the turntable 114.

[0083] At step S514, the local signal generator 118 generates a local signal. In this example, the local signal is a pseudo-random number sequence that replicates the positioning signal 14. In general, the received positioning signal may include any known or unknown transmission information pattern, whether digital or analog. The presence of such a pattern may be determined by a cross-correlation process using a local copy of the same pattern (in this example, the local signal). The received positioning signal may be encoded with a code chip that can be used for ranging. Examples of such received signals include GPS signals, which include gold codes encoded in radio transmissions. Another example is an extended training sequence used in GSM cellular transmissions.

[0084] At step S516 , the correlator 120 is configured to correlate the local signal with the positioning signal 14 received from the first satellite 2 to provide a correlated signal.

[0085] At step S518, the motion compensation module 124 performs motion compensation on at least one of the local signal, the received positioning signal 14, or the correlation signal. This involves adjusting the correlation signal selected for motion compensation to account for changes in the received positioning signal 14 due to relative motion between the antenna 102 and the first satellite 2 along the line of sight. These techniques are described in WO2017 / 163042, however any other suitable motion compensation technique may be used. When motion compensation is applied to the positioning signal 14 or the local signal, step S518 may occur before step S516.

[0086] By providing motion compensation in a direction extending between the antenna 102 and the first satellite 2, preferential gain of signals received along that direction can be achieved. Therefore, the line-of-sight signal between the antenna 102 and the first satellite 2 will be received in priority over the gain of reflected signals received from different directions (for example, from nearby buildings). In a GNSS receiver, this can significantly improve positioning accuracy and better estimate signal phase because non-line-of-sight signals (such as reflected signals) are significantly suppressed. Applying motion compensation ensures that the line-of-sight signal can achieve the highest correlation, even if the absolute power of the signal is less than the absolute power of the non-line-of-sight signal. However, even in the absence of reflected signals, applying motion compensation will improve the signal-to-noise ratio of the received positioning signal, thereby enabling detection of extremely weak line-of-sight signals.

[0087] Motion compensation can be performed by generating a phasor sequence and combining it with at least one of the local signal, the received signal 14, or the correlation signal. In this case, the motion compensation module 124 receives the determined movement of the antenna 102 from the motion determination module 122 and generates a phasor sequence based on the antenna movement in the line of sight (straight line) direction between the antenna 102 and the first satellite 2.

[0088] Each phasor sequence φ comprises a plurality of phasors, wherein each phasor generally has the same duration as a sample of the received signal. During the period of measuring the received signal and the antenna movement, the phasors φ in the generated phasor sequence φ i The number N (i=1...N) is usually the same as the number of samples of the received signal and the number of samples of the local signal. i represents a phase and / or amplitude compensation based on the motion of the antenna 102 at time t, such that a phasor sequence consisting of a plurality of phasors indicates the motion of the antenna along a particular direction as a function of time. For example, the measured or assumed velocity of the antenna 102 from the motion determination module 122 may be used to determine a Doppler shift due to the motion of the antenna 102 along the line of sight direction of the first satellite 2. The Doppler shift may then be integrated over time to estimate a phase value.

[0089] Therefore, the phasor sequence may also be referred to as a "motion compensated" phasor sequence.

[0090] Phase φ i is a transformation in phase space and is a complex value representing the in-phase component of the motion-compensated phasor sequence via its real component and the quadrature-phase component in the motion-compensated phasor sequence via its imaginary component. i It is typically a cyclic phasor and can be represented in a variety of different ways, for example, as a clockwise rotation from a real axis or a counterclockwise rotation from an imaginary axis. As described above, the phasor sequence for each direction indicates the measured or assumed movement of the antenna 102 along that direction. Once the phasor sequence has been generated, at step S518, the phasor sequence can be combined with any one of the local signal, the received signal 14, or the related signal to perform motion compensation. It is obvious to those skilled in the art how to generate a phasor sequence in each case and combine the generated phasor sequence with the local signal, the received signal 14, or the related signal. Further details are also provided in WO 2017 / 163042.

[0091] In step S520, the positioning calculator 126 calculates a positioning range or pseudorange associated with the first satellite 2 based on the result of the motion compensation correlation. As known in the art, the precise position of the positioning device 100 can be inferred by obtaining positioning ranges from at least three additional reference sources and determining the intersection between the four calculated ranges.

[0092] In step S522, the controller 108 returns to the previous step S502 to perform steps S502 to S520 for the additional sources from which the antenna 102 is receiving positioning signals, although in practice these steps will typically be performed in parallel. For example, these steps may be repeated for a second satellite 4, a ground source 6, and another remote reference source.

[0093] At step S524 , the positioning calculator 126 calculates the position of the positioning device 100 using the at least four determined ranges.

[0094] In addition to antenna 102, the positioning device may also include other antennas on a turntable 114 (or other mobile mechanism), each of which may be configured to receive different types of positioning signals, such as L1 and L5 signals. In this case, method 500 may be performed separately for each antenna on the turntable 114 in parallel or sequentially.

[0095] Further applications, uses and details of motion compensation may be found in commonly assigned patent publications WO 2017 / 163042, WO 2019 / 063983 and WO 2019 / 058119, the entire contents of which are incorporated herein by reference.

[0096] Here, multiple examples have been given to illustrate various features, and it is not intended to be so limited. Any one or more features may not be limited to the specific examples presented herein, regardless of any order, combination or connection described. In fact, it should be understood that any combination of features and / or elements described in the above example manner can be envisioned, including any changes or modifications that are not listed but can achieve the same. Unless otherwise stated, any one or more features can be combined in any order.

[0097] As mentioned above, unless otherwise specified, the drawings provided herein are for illustrative purposes only and are not meant to impose any structural limitations. Various modifications to any structure shown in the drawings are considered to be within the scope of the present invention as set forth herein. The present invention is not intended to be limited to any scope of the claim language.

[0098] Unless otherwise stated, the use of "coupled" or "connected" does not mean that the coupling or connection is limited to physical coupling or connection, but should be understood to include communication coupling, including wireless transmissions and protocols.

[0099] Any block, step, module or other method described herein may represent one or more instructions that may be stored as software on a non-transient computer-readable medium and / or executed by hardware. Any such block, module, step or other method may be executed in an automated manner by various software and / or hardware combinations, including using dedicated hardware designed for this purpose. As described above, any number of blocks, steps or modules may be executed in any order or not at all, including substantially simultaneously, i.e., within the tolerance of the system executing the blocks, steps, or modules.

[0100] Where conditional language is used, including but not limited to "can", "can", "may", or "might", it should be understood that the associated features or elements are not required. Therefore, where conditional language is used, unless otherwise specified, elements and / or features should be understood to be optionally present in at least some examples, and not necessarily conditional on anything.

[0101] If a list is enumerated with alternatives or conjunctions (e.g., one or more of A, B, and / or C), unless otherwise specified, it should be understood to include one or more of each element, including any one or more combinations of any number of the enumerated elements (e.g., A, AB, AC, ABC, ABB, etc.). When "and / or" is used, it should be understood that these elements can be connected in alternative or conjunction form.

[0102] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the following claims.

Claims

1. An apparatus configured to process a radio signal, comprising: Mobile platforms; an antenna configured to receive a signal from a remote source in a first direction; a moving mechanism mounted on the platform, wherein the antenna is mounted on the moving mechanism, and the moving mechanism is configured to move the antenna relative to the platform; as well as A controller configured to: Generate local signals; determining a motion component of the antenna along the first direction; correlating the local signal with the received signal to generate a correlated signal; as well as At least one of the local signal, the received signal, and the correlation signal is motion compensated based on the determined motion of the antenna in the first direction. 2 . The apparatus of claim 1 , wherein the movement mechanism is configured to periodically move the antenna relative to the platform.

3. The apparatus of claim 2, wherein the movement mechanism is configured to provide a substantially circular or elliptical movement of the antenna relative to the platform. The device according to claim 3 , wherein the moving mechanism comprises a turntable, and the antenna is mounted on the turntable.

5. The apparatus according to claim 1 or 2, wherein the moving mechanism is configured to move the antenna in one dimension, two dimensions or three dimensions.

6. The apparatus of any preceding claim, further comprising a motion sensor configured to measure the motion of the platform, wherein the controller is configured to determine the motion of the platform based on measurements performed by the motion sensor.

7. The apparatus of claim 6, wherein the controller is configured to instruct the movement mechanism to move the antenna and perform motion compensation in response to determining that the platform is moving below a threshold speed in at least the first direction.

8. The device according to any one of claims 1 to 5, wherein: The movement mechanism is configured to continuously move the antenna regardless of whether the controller determines that the platform is in motion or stationary.

9. Apparatus according to any preceding claim, wherein the platform is provided in or on a vehicle, or in or on a human-portable device.

10. Apparatus according to any preceding claim, wherein the platform is provided in or on a body comprising sporting equipment.

11. The apparatus according to claims 1-8, wherein the platform is provided in a mobile device such as a smartphone or a laptop.

12. The apparatus according to any one of the preceding claims, comprising a plurality of moving mechanisms and a plurality of antennas correspondingly mounted to the plurality of moving mechanisms, wherein each of the plurality of moving mechanisms is configured to move a corresponding antenna of the plurality of antennas relative to the platform.

13. An apparatus according to any preceding claim, wherein the movement mechanism comprises a further antenna.

14. A method for processing a radio signal, comprising: Provide local signals; providing an antenna capable of being movably mounted to a mobile platform; receiving a signal at the antenna from a remote source in a first direction; moving the antenna relative to the platform; determining a motion component of the antenna in the first direction; correlating the local signal with the received signal to provide a correlated signal; as well as At least one of the local signal, the received signal, and the correlation signal is motion compensated based on the determined motion of the antenna in the first direction.

15. The method according to claim 14, wherein: Moving the antenna includes periodically moving the antenna relative to the platform.

16. The method of claim 15, wherein periodically moving the antenna comprises providing a substantially circular or elliptical motion of the antenna relative to the platform.

17. The method according to any one of claims 14 to 16, wherein: The steps of moving the antenna and providing motion compensation are performed in response to determining that the platform is moving below a threshold velocity in at least the first direction.

18. The method according to any one of claims 14 to 16, wherein: Moving the antenna includes continuously moving the antenna regardless of whether the platform is determined to be in motion or stationary.

19. The method according to claim 14 or 15, wherein: Moving the antenna includes moving the antenna in one dimension, two dimensions, or three dimensions.

20. A non-transitory computer readable medium storing executable instructions, which when executed by a processor causes the processor to perform the steps comprising: Provide local signals; moving an antenna movably mounted to a mobile platform relative to the platform, wherein the antenna is configured to receive a signal from a remote source in a first direction; determining a motion component of the antenna in the first direction; correlating the local signal with the received signal to provide a correlated signal; as well as At least one of the local signal, the received signal, and the correlation signal is motion compensated based on the determined motion of the antenna in the first direction.

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