Method and apparatus for processing wireless signals

Abstract

A system is disclosed, the system comprising a mobile platform (113), an antenna (102) configured to receive a signal (14) from a remote source (2) in a first direction, a movement mechanism (114) attached to the platform, the movement mechanism (114) to which the antenna is attached and configured to move the antenna relative to the platform, and a control unit (108) configured to generate a local signal, determine a movement component of the antenna in the first direction, correlate the local signal with the received signal to provide a correlation signal, and perform movement compensation on at least one of the local signal, the signal from the remote source, and the correlation signal based on the determined movement of the antenna in the first direction.

Description

Technical Field

[0001] The present invention relates to a positioning or communication system. More specifically, the present invention relates to a positioning or communication system that can improve signal reception using motion compensation.

Background Art

[0002] Some positioning systems utilize the movement between a positioning device and a reference source to determine the more accurate position of the positioning device. One such technique known as the SUPERCORRELATION (trademark) technique is described in International Publication No. WO 2017 / 163042 by the same applicant, which is hereby incorporated by reference in its entirety, and performs correlation using motion compensation for the movement of the receiver. The motion-compensated signal correlation is particularly useful indoors or in outdoor environments where buildings can block and reflect signals from remote reference sources, making it difficult to detect signals.

[0003] It is desired to be able to perform motion compensation even while the positioning device is stationary or while the movement between the positioning device and the reference source is relatively small. Further, it is required to be able to perform motion compensation for positioning signals received from a wider range of angles for a given positioning device at once. Motion compensation can also be used to process wireless signals other than positioning signals. Similarly, it is also advantageous to be able to perform motion compensation for processing wireless signals when there is a relatively small movement between the source and the receiver.

[0004] The object of the present invention is to address these requirements.

Summary of the Invention

[0005] According to one aspect of the present invention, there is provided an apparatus configured to process wireless signals, the apparatus comprising: a mobile platform; an antenna configured to receive signals from a remote source in a first direction; a moving mechanism attached to the platform, to which the antenna is attached and which is configured to move the antenna relative to the platform; and a control unit configured to generate a local signal, determine a movement component of the antenna along the first direction, provide a correlation signal by correlating the local signal with the received signal, and perform movement compensation on at least one of the local signal, the received signal, and the correlation signal based on the determined movement of the antenna in the first direction.

[0006] To perform movement compensation, at least some relative movement between the remote source and the antenna along the first direction is required. The first direction may be the straight-line direction between the remote source and the antenna, whether or not blocked by intervening objects, or another relevant direction. The moving mechanism of embodiments of the present invention moves the antenna in the first direction. Thereby, the apparatus can perform movement compensation even when there is little or no relative movement between the platform and the remote source in the first direction. In one exemplary scenario, the platform may be stationary. In another scenario, the platform may be moving in a direction substantially perpendicular to the first direction. In both cases, the movement of the antenna in the first direction provided by the moving mechanism enables movement compensation to be performed despite the lack of movement of the platform in the first direction. In this way, movement compensation can be used in a wider variety of situations.

[0007] The apparatus 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 terrestrial source. In other embodiments, the apparatus may be designed as a transceiver for communication signals such as WiFi signals, Bluetooth® signals, cellular signals, etc.

[0008] The mobile platform can also be described as a platform attached to a body equipped with any type of moving device, such as wheels for ground travel or thrusters for flight. The mobile platform can be provided in or on any mobile device. The mobile device can be configured to be carried or move its position when performing motion compensation. For example, the mobile device may include one or more sensors that enable determination of the complex motion of the antenna.

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

[0010] The moving mechanism can be configured to move the antenna linearly or non-linearly relative to the platform. In the case of an antenna moving along a fixed linear path, there is ambiguity in the Doppler measurements coming from off-axis directions. The only way to resolve these ambiguities is to ensure that the path is not straight. With 2D and ideally 3D non-linear motion, it is ensured that various directions around the platform can be uniquely resolved by their Doppler profiles. It is also advantageous to maintain the movement of the antenna even when the platform is stationary. For this reason, the non-linear motion generated by the moving mechanism can bring better results. Nevertheless, it is still possible to perform motion compensation in a more diverse range of situations by using the moving mechanism to generate linear motion of the antenna.

[0011] There may be two or more antennas on the platform or the moving mechanism. The apparatus may comprise a first antenna attached to the moving mechanism configured to receive a first type of signal and a second antenna attached to the moving mechanism configured to receive a second type of signal. For example, a GNSS receiver may use separate antennas for the L1 frequency and the L5 frequency. Alternatively, two or more antennas may be assigned to each frequency during use.

[0012] The platform may comprise a base or any other suitable structure to which the moving mechanism can be attached. In one example, the platform may be the device or the inner base or housing of the positioning device to which various electronic components of the positioning device are attached.

[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 may alternatively be called a positioning source or a reference source and may operate as part of any navigation system known in the art. In general, the positioning system can include any combination of satellite sources, terrestrial sources or other types of reference sources.

[0014] The local signal may be a replica of the received signal, or a pseudo-random number sequence from a GNSS satellite, or other well-known content within a communication channel broadcast such as a synchronization word.

[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 received signal, the local signal, or a correlation signal resulting from the correlation between the received signal and the local signal. Similarly, the correlation step may be performed using known correlation techniques in GNSS or other positioning or communication systems.

[0016] The step of providing motion compensation is to generate a phaser series including one or more phasers indicating an amplitude and / or phase change introduced into the received signal as a result of a determined antenna movement in a first direction, each phaser including a phase angle and an amplitude, and may include synthesizing the phaser series with at least one of the local signal, the received signal, and the correlation signal.

[0017] The phaser series includes one or more phasers indicating an amplitude and / or phase change introduced into the received signal as a result of the determined antenna movement. Each phaser includes at least one of an amplitude and a phase angle explaining the determined antenna movement in each direction. Typically, the phaser series is derived as a function of time from the determined antenna movement. For example, each phaser within the phaser series may indicate the determined antenna movement within a specific time interval. Thus, the resulting phaser series indicates the determined antenna movement within a time composed of individual time intervals (e.g., corresponding to the antenna movement). The phaser series may timely reflect the detailed movement of the antenna. For example, a plurality of phasers within the phaser series may reflect the movement of the antenna while being moved by a movement mechanism.

[0018] In one embodiment, the movement mechanism is configured to move the antenna periodically in one, two, or three spatial dimensions relative to the platform. In this way, the movement mechanism can continuously move the antenna along a given path. Thereby, movement compensation can be performed at any time using the periodic movement. Furthermore, movement mechanisms with simple implementation generally utilize some form of periodic movement.

[0019] In one embodiment, the movement mechanism is configured to move the antenna in a substantially circular motion relative to the platform. Thereby, the angular sensitivity of the antenna can be improved. Furthermore, it has been found that movement compensation is more effective when there is a non-linear and non-lateral movement between the antenna and the remote source. Therefore, by moving continuously and variably non-linearly, the effectiveness of movement compensation is improved. In other embodiments, other types of movement such as linear movement, circular movement, elliptical movement, reciprocating movement, random movement, dither movement, or oscillatory movement may be provided by the movement mechanism.

[0020] In one embodiment, the movement mechanism includes a turntable to which the antenna is attached. The turntable may be a particularly simple implementation of the movement mechanism, thereby reducing the cost of implementing the movement mechanism. The turntable may be driven by an electric motor or any other means.

[0021] The turntable or any other means that provides non-linear movement may be configured to move the antenna at a speed such that it 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 such as, but not limited to, sliding, vibrating, oscillating, rocking, turning, fine movement, or shaking may be provided.

[0023] In one embodiment, the apparatus further comprises a motion sensor configured to measure the movement of the platform, and the control unit is configured to determine the movement of the platform based on the measurement performed by the motion sensor.

[0024] The control unit can also be configured to command 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 may be more energy efficient by operating the movement mechanism only when motion compensation in the first direction is required. In some examples, the control unit may determine the component of the movement of the platform in the first direction before commanding the movement mechanism to move the antenna. In other examples, the control unit 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 continuously performs its own linear or non-linear movement permanently regardless of the movement of the platform.

[0025] The motion sensor may include one or more of any type of motion detection component, such as an inertial sensor or a gyro sensor configured to determine acceleration, or a magnetometer configured to determine orientation. The motion sensor may be disposed at the same location as the antenna to determine the movement of the antenna. For example, the motion sensor may be disposed at the same location as the antenna within the movement mechanism.

[0026] In other examples, the motion sensor may be located elsewhere, such as being 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 measured platform. In one example, the sensing element may be located in the same location as the antenna, and the motion sensor may track the movement of the sensing element. Alternatively, the motion of the antenna by the movement mechanism may be calculated based on the measured motion of the platform and the predictable motion of the movement mechanism. Determination of a particular component of the motion along the direction to the remote source can be performed using any suitable technique known in the art.

[0027] In another example, there is a motion sensor attached to the platform and a separate motion sensor located in the same location as the antenna.

[0028] The control unit may be able to estimate that the platform is moving in a particular direction at a particular speed based on a previous series of positioning calculations. For example, if the platform is incorporated into a device that is moving along a long straight road at a constant speed, the control unit may be able to estimate or determine the measurement of the platform rather than using the direct measurement values from the motion sensor.

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

[0030] In some embodiments, the platform is provided inside or on the vehicle. The platform may be attached to a wheeled body. In one example, the platform may be provided on the roof of the vehicle, thereby avoiding attenuation of the received positioning signal by the vehicle body or roof. The movement mechanism may be arranged with respect to a series of wheels of the vehicle such that the movement mechanism can move the antenna in a plane substantially perpendicular to the series of wheels. In this way, while the movement of the platform can result in one-dimensional antenna movement, the movement mechanism can result in vertical antenna movement where the platform itself cannot move. This is particularly advantageous for a platform moving in an urban environment where signals are reflected from high-rise buildings on both sides of the direction of travel, for example. The movement of the antenna perpendicular to the direction of travel of the platform allows the system to distinguish signals reflected from buildings on both sides of the street.

[0031] In some embodiments, the platform is provided on 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, as is already known in the art, it may be necessary to remove the effects of phase advance or delay caused by a determined rotation of the antenna.

[0033] The movement mechanism can be configured to move the antenna in one, two, or three dimensions. In the case of this two-dimensional or three-dimensional movement, it is possible to improve the flexibility of the movement mechanism and perform movement compensation on signals received from a wider range of angles with respect to the platform in a given orientation. The movement mechanism can be any type of movement mechanism configured to generate movement of the antenna along one, two, or three dimensions or axes.

[0034] In one embodiment, the apparatus includes a plurality of moving mechanisms and a plurality of antennas respectively attached to the plurality of moving mechanisms. Each of the plurality of moving mechanisms is configured to move the corresponding antenna among the plurality of antennas relative to the platform. In other words, the apparatus may include a first moving mechanism and a second moving mechanism to which a first antenna and a second antenna are respectively attached.

[0035] Each antenna may receive respective signals that can be processed by the control unit using motion compensation enabled by the movement of each antenna relative to the platform caused by the corresponding moving mechanism. The platform may have two or more moving mechanisms each supporting one or more antennas. The moving mechanisms may be configured to move independently of each other in orthogonal directions, thus providing 2D movement. Three moving mechanisms that move the antennas orthogonally may provide 3D movement that can be used to perform motion compensation in any direction.

[0036] In one embodiment, the moving mechanism may include an additional antenna, or in other words, may include a first antenna and a second antenna. The moving mechanism can be configured to move the second antenna relative to the platform, enabling the control unit to perform motion compensation on the signal received by the second antenna. The first antenna and the second antenna may be configured to receive different radio frequencies. In this way, the apparatus can improve the detection of several different frequency bands in a compact arrangement. Three or more antennas each configured to detect wireless signals in different bands may be provided on a single moving mechanism.

[0037] According to one aspect of the present invention, there is provided a method for processing a radio signal that can be executed in a positioning system. The method includes providing a local signal, providing an antenna movably attached to a mobile platform, receiving a signal from a remote source in a first direction with the antenna, moving the antenna relative to the platform, determining the movement of the antenna, correlating the local signal with the received signal to provide a correlation signal, and performing movement compensation on at least one of the local signal, the received signal, and the correlation signal based on the determined movement of the antenna in the first direction.

[0038] According to one aspect of the present invention, there is provided a non-transitory computer-readable medium storing executable instructions that, when executed by a processor, cause the processor to perform steps including providing a local signal, moving an antenna movably attached to a mobile platform relative to the platform, where the antenna receives a signal from a remote source in a first direction, determining the movement of the antenna, correlating the local signal with the received signal to provide a correlation signal, and performing movement compensation on at least one of the local signal, the received signal, and the correlation signal based on the determined movement of the antenna in the first direction.

Brief Description of the Drawings

[0039] Here, embodiments of the present invention will be described by way of example with reference to the drawings.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

[0040] FIG. 1 is a schematic diagram showing, as an example, an environment in which a positioning solution can be provided using the method and positioning system of the present invention. FIG. 2 is a schematic diagram of a positioning device 100 and a control system of the positioning device 100.

[0041] Referring to FIGS. 1 and 2, the positioning system 1 includes a positioning device 100 having an antenna 102 configured to receive signals from a remote reference source. In this example, the positioning device 100 of the user 10 receives wireless signals via the antenna 102 from a remote reference source including a first satellite 2, a second satellite 4, and a remote terrestrial source 6. The high-rise building 12 bisects the line of sight from the positioning device 100 to the second satellite 2 and the terrestrial source 6. The building 12 attenuates the signals from the first satellite 2 and the terrestrial source 6, weakening the signals and thus making it more difficult for the positioning device 100 to obtain an accurate position measurement. The same building 12 may also provide a path for the reflected signal from the second satellite 4 to the antenna 102.

[0042] As shown in FIG. 2, an exemplary positioning device 100 includes an antenna 102, a receiver 104 connected to the antenna 102, a local oscillator 106, a control unit 108, a memory 110, a motion sensor 112, and a turntable 114.

[0043] The receiver 104 is configured to process the 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.

[0044] The local oscillator 106 is configured to provide timing signals for various applications in the positioning device 100, including generating a local signal. The local oscillator 106 may be simple and low-cost, and in one example may include a crystal oscillator.

[0045] The control unit 108 is configured to control the operation of the electronic components of the positioning device 100, including the components shown in FIG. 2 and other components of the positioning device 100. In this example, the control unit 108 includes a single processor 109 that operates a plurality of modules configured to perform specific functions, which will be further described below. In other embodiments, the modules may be provided separately with different associated processors, or may be distributed across a network.

[0046] The memory 110 may include a non-transitory computer-readable medium, such as a combination of a random access and read-only memory unit, configured to store executable instructions 111 for various modules of the control unit 108. The memory 110 may also store data 113 used to implement the various modules and instructions 111. The instructions 111 can be executed by the processor 109 to perform method 500, which will be further described below, and other operations of the positioning system 1 described herein.

[0047] The motion sensor 112 is configured to determine the movement of the antenna 102 in a specific direction, such as speed and acceleration. The motion sensor 112 may include a plurality of separate motion and / or orientation sensors, such as inertial sensors, gyroscopes, or magnetometers.

[0048] The turntable 114 includes a circular base 115 and a motor (not shown) configured to drive the base 115 to rotate continuously when commanded by the control unit 108. The antenna 102 is attached to the base 115 so as to follow a substantially circular path when the base 115 is rotated by the motor. In other exemplary embodiments, the turntable 114 may include other suitable components such as a non-circular base or other means for driving the base.

[0049] In this example, the motion sensor 112 is disposed at the same location as the antenna 102 within the base 115. Accordingly, the motion sensor 112 can detect the movement of the antenna 102 resulting from the rotation of the turntable 114 and the movement of the platform 113.

[0050] Alternatively, the motion sensor 112 may be disposed at other locations to determine the movement of the positioning device 100. In this case, another aspect of the movement of the antenna 102 caused by the turntable 114 can be determined according to a predictable movement formula generated by the turntable 114. Alternatively, the movement of the antenna 102 can be determined by an additional motion sensor or rotation sensor such as a tachometer. In this case, the composite movement of the antenna 102 may be calculated based on the measurements from the motion sensor 112 and the additional motion sensor implemented to determine the movement of the positioning device 100.

[0051] In this example, the positioning device 100 is a smartphone, and the antenna 102 and the turntable 114 are housed inside the smartphone. However, for the purpose of illustration, the turntable 114 and the antenna 102 are shown as external to the positioning device 100 in FIG. 2. In other examples, the positioning device 100 may be configured as a laptop, a vehicle, or any other type of portable device.

[0052] The control unit 108 includes a number 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 calculation unit 126. The functions of these modules of the control unit 108 will be further described below with reference to FIGS. 5A and 5B. These modules may be hardware, software, or a combination thereof. In one embodiment, one or more of the modules may be implemented by executing software instructions 111 stored in the memory 110 by the processor 109 of the control unit 108.

[0053] FIG. 3 shows a schematic diagram of a part of the positioning system 1 in an exemplary usage scenario. An axis is shown in the lower left corner of FIG. 3, and the Y-axis extends within the page.

[0054] The positioning device 100 further includes a platform 113 fixed to the positioning device 100. As shown in FIG. 3, the turntable 114 is attached to the platform 113 so as to be rotatable with respect to the platform 113 when the base 115 is driven by a motor. In this example, the turntable 114 and the platform 113 are incorporated within the housing (not shown) of the positioning device 100.

[0055] In the example of FIG. 3, the positioning device 100 is stationary with respect to the Earth, which can occur when the user 10 holds the positioning device 100 stationary. The first satellite 2 is oriented and moved relative to the positioning device so that there is no relative movement or only a small amount of relative movement between the platform 113 and the first remote source 2 along the shared line of sight between the platform 113 and the first remote source 2.

[0056] As shown in FIG. 1, the building 12 obstructs the positioning signal 14 received along the line of sight from the first satellite 2, thereby attenuating the positioning signal 14 and making detection more difficult than the reflected signal from the first satellite 2. Usually, when using a known positioning system, even if it is desired to perform motion compensation, it is impossible because there is no movement in the line of sight direction. Performing motion compensation can increase the reception of the line of sight signal compared to the non-line of sight signal. Thereby, a very weak line of sight signal can be detected. In other scenarios, by performing motion compensation, the receiver 104 can lock onto the line of sight signal rather than the reflected signal that generates a less accurate pseudorange. However, known positioning systems require movement of the positioning device 100, or equivalently the platform 113 to which the antenna 102 is attached, along the line of sight direction to the first satellite 2 in order to perform motion compensation.

[0057] To solve this problem, the control unit 108 is configured to command the turntable 114 to rotate so as to generate movement of the antenna 102 along the line of sight to the first satellite 2, as indicated by arrow B in FIG. 3. Thereby, motion compensation can be performed by the control unit 108 despite the fact that there is not enough relative movement in the line of sight direction between the platform 113 and the first satellite 2 to perform motion compensation.

[0058] FIG. 4 shows a schematic diagram of a part of the positioning system 1 in an alternative exemplary usage scenario. An axis is shown in the lower left corner of FIG. 4, and the Y-axis extends within the page.

[0059] In this exemplary usage, the positioning device 100, and thus the platform 113 and the antenna 102, are moving in the positive Y direction as indicated by arrow C. The second satellite 4 is arranged away in the positive Z and Y directions, and the first satellite 2 is arranged away in the positive Z and X directions and is moving substantially parallel to the Y-axis, as in the example of FIG. 3.

[0060] Typically, using a known positioning system, in this situation, based on the movement of the platform 113 along the Y direction, movement compensation can only be performed on the positioning signal 16 received from the second satellite 4. However, the turntable 114 can move the antenna 102 as shown by the arrow B to generate movement along the X direction, enabling movement compensation to be performed on the signal 14 received from the first satellite 2. Thereby, the positioning device 100 can determine the positioning range from both the first satellite 2 and the second satellite 4. In this way, the turntable 114 increases the range of angles at which signals that can be more effectively detected using movement compensation can be received. In other words, by using the movement of the antenna 102 relative to the platform 113, the angular sensitivity of the antenna 102 is improved.

[0061] More specifically, each axis along which the antenna 102 moves relative to the reference source generates two "sensitivity cones" in space (one cone for each direction along the axis, and each cone branches from the antenna 102). Each cone is centered on the axis of movement. Movement compensation can increase the reception of very weak line-of-sight signals from remote sources near the axis of the cone, but movement compensation is not very effective in increasing the reception of line-of-sight signals from remote sources located in space or on the horizon further away from the axis of movement. In the case of a remote source perpendicular to the axis of movement, by performing movement compensation, the positioning system 1 cannot increase the reception of line-of-sight positioning signals.

[0062] In this example, the movement C of the platform 113 can generate the first sensitivity cone along the Y axis, and the rotation B of the turntable 114 can generate the second sensitivity cone along the X axis.

[0063] The second sensitivity cone generated by the rotation B of the antenna 102 sweeps the air when the base 115 rotates to move the antenna 102 along a circular path. Therefore, motion compensation can be performed for positioning signals received from any direction, except when the remote source is directly overhead. For this reason, rotational motion is particularly preferred. However, it has also been found that motion compensation is more effective in cases based on the non-linear motion also brought about by rotational motion.

[0064] The above-described embodiments have been described with respect to a positioning device and positioning signals received from a satellite or other positioning source. However, motion compensation can also be used to more effectively process wireless signals in other systems such as communication channels. In this case, it is similarly advantageous that motion compensation between the wireless source and the receiver can be performed in various motion scenarios. It should be understood that the positioning device 100, positioning system 1 and method 500 of the present invention described herein can equally be applied to other types of systems that utilize wireless signals.

[0065] Figures 5A and 5B show an exemplary method 500 according to the present invention for determining the position of the positioning device 100 using the positioning system 1.

[0066] In step 502, the reference source selector 116 selects a specific 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, and the first satellite 2 radiates the positioning signal 14 to the antenna 102 along the line of sight. The positioning signal 14 is received by the antenna 102 in a state of weak signal strength due to attenuation by the high-rise building 12 that intersects the line of sight from the first satellite 2 to the antenna 102. Therefore, the positioning signal 14 must be processed using motion compensation to improve the sensitivity of detection.

[0067] Steps S504 to S508 can be optionally executed to determine when to operate the turntable 114 when the turntable 114 is not continuously but selectively operated. Therefore, in steps S504 to S508, the turntable 114 is stationary, and thus the antenna 102 is stationary with respect to the platform 113.

[0068] In step S504, the movement determination module 122 determines the movement of the antenna 102. The movement determination module 122 may utilize data provided by the movement sensor 112, which may include multiple measurements from movement sensors and / or orientation sensors of different components, to determine the movement of the antenna 102. Specifically, the movement determination module 122 determines the movement along the line of sight to the currently selected positioning source, in this case the first satellite 2. Using the approximate position of the first satellite 2 and the approximate position of the positioning device 100, the direction of the line of sight can be determined. Next, using this line of sight direction, the relative movement between the antenna 102 and the first satellite 2 can be calculated. The approximate position and direction of the movement of the first satellite 2 may be locally stored in the data 113 of the memory 110 in the look-up table, or may be retrievable from satellite ephemeris or an online source as is well understood in the art.

[0069] The movement of the antenna 102 can be directly measured using the movement sensor 112 as described above. Alternatively, the movement can be estimated or inferred based on previous measurements from the movement sensor 112 or recent positioning calculations. For example, if it is calculated or measured that the platform 113 is moving in a straight line at a constant speed, for example, during driving or while on a train, it may be possible to estimate the movement of the antenna 102 based on calculations. This may be simpler or less computationally complex than performing measurements in some cases.

[0070] In step S506, the motion determination module 122 optionally determines that the platform 113 is moving below a threshold speed in the line-of-sight direction to the first satellite 2. Accordingly, the control unit 108 infers that it is not possible to perform motion compensation using only the motion of the platform 113. Alternatively, the motion determination module 122 may determine that the platform 113 is moving below a threshold speed in any direction, which is simpler and computationally less complex.

[0071] In step S508, in response to that determination, the control unit 108 instructs the turntable 114 to move to generate a non-linear motion of the antenna 102 with respect to the platform 113. Thereby, even while the platform is stationary, a line-of-sight movement sufficient to perform motion compensation between the antenna 102 and the first satellite 2 is generated.

[0072] Alternatively, the turntable 114 may be configured to rotate continuously while the positioning device 100 is operating, in which case steps S504, S506, and S508 are not required.

[0073] The turntable 114 may be configured to rotate at a specific rotational speed. In some examples, the control unit 108 may instruct the turntable to change the rotational speed according to the relative orientation of the platform 113 and the first satellite 2 in order to maximize the effectiveness of motion compensation. Similarly, other means for causing a rotational motion of the antenna 102 may be configured to rotate in the same way or to vary the rotational speed.

[0074] In step S510, the antenna 102 receives the positioning signal 14 from the first satellite 2.

[0075] In step S512, the motion determination module 122 determines the operation of the antenna 102. The motion sensor 112 is disposed at the same location as 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 one alternative embodiment, the motion sensor 112 may be disposed at other locations 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 equations stored in the memory 110, which may be used to infer the speed and direction of the antenna 102 when the positioning signal 14 is received.

[0076] In any case, the motion determination module 122 performs calculations to determine the motion of the antenna 102 along the line-of-sight direction. This motion in the line-of-sight direction is used in subsequent steps to perform motion compensation. If it is determined in step S506 that the platform 113 is stationary, the motion of the antenna 102 consists only of circular motion caused by the turntable 114.

[0077] In 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 pattern of the transmitted information, either digital or analog. The presence of such a pattern can be determined by a cross-correlation process using a local copy of the same pattern (the local signal in this example). The received positioning signal may be encoded with a chipping code that can be used for ranging. Examples of such received signals include GPS signals that include a Gold code encoded within a wireless transmission. Another example is the extended training sequence used in GSM (registered trademark) cellular transmissions.

[0078] In step S516, the correlator 120 is configured to correlate a local signal with the positioning signal 14 received from the first satellite 2 to provide a correlation signal.

[0079] In 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. Performing this motion compensation includes adjusting the relevant signal selected for motion compensation to account for changes in the received positioning signal 14 caused by relative motion along the line of sight between the antenna 102 and the first satellite 2. These techniques are described in International Publication No. WO 2017 / 163042, but any other suitable motion compensation technique can also be used. Step S518 may be performed before step S516 if motion compensation is applied to the positioning signal 14 or the local signal.

[0080] By performing motion compensation in the direction extending between the antenna 102 and the first satellite 2, it is possible to preferentially receive signals received along this direction. Thus, the line-of-sight signal between the antenna 102 and the first satellite 2 is preferentially received over signals received in different directions, such as reflected signals from nearby buildings. In a GNSS receiver, since non-line-of-sight signals (e.g., reflected signals) are significantly suppressed, this can lead to a significant improvement in positioning accuracy and a better estimation of the signal phase. Applying motion compensation ensures that the highest correlation can be achieved for the line-of-sight signal even if the absolute output of the line-of-sight signal is smaller than the absolute output of the non-line-of-sight signal. However, even in the absence of reflected signals, applying motion compensation improves the signal-to-noise ratio of the received positioning signal and enables the detection of extremely weak line-of-sight signals.

[0081] Motion compensation can be performed by generating a phaser 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 phaser sequence according to the movement (linear) of the antenna in the line-of-sight direction between the antenna 102 and the first satellite 2.

[0082] Each phaser sequence φ includes a plurality of phasers, and each phaser typically has the same duration as the samples of the received signal. Since there are samples of the received signal and samples of the local signal during the time when the signal is received and the movement of the antenna is measured, the generated phaser sequence φ typically has the same number N of phasers φ i (I = 1..N). Each phaser φ i represents phase and amplitude compensation based on the movement of the antenna 102 at time t such that the phaser sequence composed of a plurality of phasers indicates the movement of the antenna along a specific direction as a function of time. For example, the measured or estimated velocity of the antenna 102 from the motion determination module 122 can be used to determine the Doppler frequency shift due to the movement of the antenna 102 along the line-of-sight direction to the first satellite 2. Then, the Doppler frequency shift may be integrated over time to estimate the phase value.

[0083] Therefore, the phaser sequence may be referred to as a "motion compensation" phaser sequence.

[0084] The phaser φ i is a transformation in the phase space and is a complex numerical value that represents the in-phase component of the motion compensation phaser sequence by its real component and represents the quadrature-phase component of the motion compensation phaser sequence by its imaginary component. The phaser φ iis typically a periodic phasor and may be represented in several different ways, for example, as a clockwise rotation from the real axis or as a counterclockwise rotation from the imaginary axis. As described above, the phasor series in each direction indicates the measured or estimated movement of the antenna 102 along that direction. Once the phasor series is generated, the phasor series can be combined with either the local signal, the received signal 14, or the correlation signal to perform motion compensation in step S518. The method of generating the phasor series and combining the generated phasor series with the local signal, the received signal 14, or the correlation signal in each case will be apparent to those skilled in the art. Further details are also described in International Publication No. WO 2017 / 163042.

[0085] In step S520, the positioning calculation unit 126 calculates a positioning range or a pseudo-range related to the first satellite 2 based on the result of the motion compensation correlation. As is known in the art, the exact 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.

[0086] In step S522, the control unit 108 returns to the previous step S502 to execute steps S502 to S520 for additional sources for which the positioning signal is being received by the antenna 102. In practice, however, these steps are generally performed in parallel. For example, these steps may be repeated for the second satellite 4, the ground source 6, and further remote reference sources.

[0087] In step S524, the positioning calculation unit 126 calculates the position of the positioning device 100 using the at least four determined ranges.

[0088] In addition to the antenna 102, the positioning device can include additional antennas on the turntable 114 (or other moving mechanism), each of which may be configured to receive different types of positioning signals such as L1 signals and L5 signals. In this case, the method 500 can be performed individually, in parallel, or sequentially for each antenna on the turntable 114.

[0089] Further uses, applications, and details of motion compensation can be found in International Publication No. WO 2017 / 163042, International Publication No. WO 2019 / 063983, and International Publication No. WO 2019 / 058119, all by the same applicant, which are hereby incorporated by reference in their entirety.

[0090] Here, multiple examples are given to illustrate various features, and it is not intended to be so limited. Any one or more features are not limited to the specific examples presented herein, regardless of the order, combination, or relationship in which they are described. In fact, it should be understood that any combination of the features and / or elements described above as examples, including any variations or modifications not listed but capable of achieving the same, is contemplated. Unless otherwise specified, any one or more features may be combined in any order.

[0091] As described above, the drawings are presented herein for illustrative purposes and do not imply any structural limitations unless otherwise specified. Various modifications to any of the structures shown in the figures are intended to be within the scope of the invention presented herein. The invention is not intended to be limited to any scope of the language of the claims.

[0092] When "coupled" or "connected" is used, unless otherwise specified, the implication that the coupling or connection is limited to a physical coupling or connection is not implied, and instead, it should be read to include communication couplings including wireless transmission and protocols.

[0093] Any block, step, module, or other described herein may represent one or more instructions stored as software on a non-transitory computer-readable medium and / or executed by hardware. Any such block, module, step, or other may be executed by various software and / or hardware combinations in an automated manner that includes the use of dedicated hardware designed to achieve such purposes. As noted above, any number of blocks, steps, or modules may be performed in any order or not at all, substantially simultaneously, i.e., within the tolerance of the system performing the blocks, steps, or modules.

[0094] It should be understood that, without limitation, when conditional language including "can", "could", "may", or "might" is used, the associated feature or element is not essential. Thus, when conditional language is used, the element and / or feature should be understood as optionally present in at least some instances and not necessarily conditioning anything, absent a separate indication.

[0095] When a list is presented in the alternative or conjunctive (e.g., one or more of A, B, and / or C), it is understood to include any one or more combinations of any number of the enumerated elements (e.g., A, AB, AC, ABC, ABB, etc.) without a separate indication. It should be understood that when "and / or" is used, the elements may be associated in the alternative or conjunctive.

[0096] The foregoing is directed to embodiments of the invention, but other and further embodiments of the invention may be devised without departing from the basic scope thereof, which is determined by the claims that follow.

Claims

1. An apparatus configured to process wireless signals, comprising: a mobile platform; an antenna configured to receive signals from a remote source in a first direction; a moving mechanism attached to the platform, to which the antenna is attached and configured to move the antenna relative to the platform; a control unit configured to generate a local signal, determine a movement component of the antenna along the first direction, correlate the local signal with the received signal to generate a correlation signal, and perform movement compensation on at least one of the local signal, the received signal, and the correlation signal based on the determined movement of the antenna in the first direction. The apparatus further comprises a control unit configured as described above. The apparatus further comprises a control unit configured as described above.

2. The apparatus according to claim 1, wherein the moving mechanism is configured to move the antenna relative to the platform periodically.

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

4. The apparatus according to claim 3, wherein the moving mechanism comprises a turntable to which the antenna is attached.

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

6. The apparatus according to any one of claims 1 to 5, further comprising a motion sensor configured to measure movement of the platform, wherein the control unit is configured to determine the movement of the platform based on measurements performed by the motion sensor.

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

8. The apparatus according to any one of claims 1 to 5, wherein the moving mechanism is configured to continuously move the antenna regardless of whether the control unit determines that the platform is moving or stationary.

9. The apparatus according to any one of claims 1 to 8, wherein the platform is provided in or on a vehicle or a portable device of a human.

10. The apparatus according to any one of claims 1 to 9, wherein the platform is provided in or on a body equipped with a moving device.

11. The apparatus according to any one of claims 1 to 8, wherein the platform is provided on a mobile device such as a smartphone or a laptop computer.

12. The apparatus according to any one of claims 1 to 11, comprising a plurality of moving mechanisms and a plurality of antennas respectively attached to the plurality of moving mechanisms, each of the plurality of moving mechanisms being configured to move a corresponding one of the plurality of antennas relative to the platform.

13. The apparatus according to any one of claims 1 to 12, wherein the moving mechanism comprises an additional antenna.

14. A method for processing a wireless signal, comprising: providing a local signal; providing an antenna movably attached to a mobile platform; receiving a signal from a remote source in a first direction with the antenna; moving the antenna relative to the platform; determining a movement component of the antenna in the first direction; correlating the local signal with the received signal to provide a correlation signal; and performing motion compensation on at least one of the local signal, the received signal, and the correlation signal based on the determined movement of the antenna in the first direction. A method.

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

16. The method according to claim 15, wherein periodically moving the antenna comprises providing a substantially circular or elliptical movement 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 a determination that the platform is moving at a speed below a threshold in at least the first direction.

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

19. The method according to claim 14 or 15, wherein the step of 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, wherein when the executable instructions are executed by a processor, providing a local signal; moving an antenna movably attached to a mobile platform relative to the platform, the antenna being 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 correlation signal; and compensating for motion of at least one of the local signal, the received signal, and the correlation signal based on the determined motion of the antenna in the first direction. A non-transitory computer-readable medium that causes the processor to execute steps including the above.

Images