Method and apparatus for using a dual-polarized antenna

Abstract

The present invention discloses a method and apparatus for using a dual-polarized antenna. The apparatus includes: an antenna assembly, the antenna assembly including an antenna configured to receive a signal and, based on the received signal, generate a first linearly polarized signal at a first feed point and a second linearly polarized signal at a second feed point; and a switching circuit configured to periodically switch between the first feed point and the second feed point based on a switching signal to select a polarized signal between the first polarized signal and the second polarized signal at a given time point.

Description

Technical Field

[0001] The present disclosure relates generally to antennas, and more particularly, to apparatus including a dual-polarized antenna assembly capable of switching between two feed points and methods of operating the same. Background Art

[0002] A Global Navigation Satellite System (GNSS) receiver receives satellite signals transmitted from the GNSS satellite constellation through an antenna. Before reaching the antenna, satellite signals may be scattered, reflected, or refracted in space by, for example, mountains or buildings, causing multipath interference at the antenna. Alternatively, the antenna may be vulnerable to spoofing attacks, which use false signals to deceive the receiver.

[0003] Multipath interference and spoofing can be mitigated by adding hardware (e.g., multiple antenna arrays) in the front end of the receiver and adding additional signal processing blocks in the back end of the receiver. However, this increases the size and cost of the receiver. Summary of the Invention

[0004] According to some embodiments of the present disclosure, a device is provided. The device includes: an antenna assembly, the antenna assembly including an antenna, the antenna configured to receive a signal and, based on the received signal, generate a first linearly polarized signal at a first feed point and a second linearly polarized signal at a second feed point; and a switching circuit configured to periodically switch between the first feed point and the second feed point based on a switching signal to select a polarized signal between the first polarized signal and the second polarized signal at a point in time. The device may also include a receiver connected to receive the selected polarized signal, the receiver configured to: process the selected polarized signal to generate at least a right-hand circularly polarized (RHCP) signal; and generate the switching signal.

[0005] According to some embodiments of the present disclosure, a device including an antenna assembly is further provided. The antenna assembly includes: an antenna configured to receive a signal and, based on the received signal, generate a plurality of first linearly polarized signals and a plurality of second linearly polarized signals; a first hybrid coupler configured to combine the plurality of first linearly polarized signals to form a first combined polarized signal; a second hybrid coupler configured to combine the plurality of second linearly polarized signals to form a second combined polarized signal; and a switching circuit configured to periodically switch between the first hybrid coupler and the second hybrid coupler based on a switching signal to select a polarized signal between the first combined polarized signal and the second combined polarized signal at a point in time.

[0006] According to some embodiments of the present disclosure, a method for operating a device is also provided, wherein the device includes: a receiver configured to generate a switching signal; and an antenna configured to receive a signal and generate a first linear polarization signal and a second linear polarization signal having different polarization directions. The method includes: generating the switching signal; based on the switching signal, using a switch included in the antenna to time-division multiplex the first polarization signal and the second polarization signal to provide a time-division multiplexed signal; receiving at least a portion of the time-division multiplexed signal through a first correlator subchannel and a second correlator subchannel; and receiving the first polarization signal through the first correlator subchannel and the second correlator subchannel. The first correlator sub-channel processes a right-hand circularly polarized (RHCP) signal by periodically switching the numerically controlled oscillator of the first correlator channel between 0° and +90° or between 0° and -90° at each switching time point of the first polarization signal and the second polarization signal; the second correlator sub-channel processes a left-hand circularly polarized (LHCP) signal by periodically switching the numerically controlled oscillator of the second correlator channel between 0° and -90° or between 0° and +90° at each switching point of the first polarization signal and the second polarization signal; and the correlated RHCP signal and the LHCP signal are recombined.

[0007] According to some embodiments of the present disclosure, a non-transitory computer-readable medium storing instructions is further provided, wherein the instructions, when executed by a processor, perform a method for controlling a device, the method comprising: generating a switching signal by the device; sending the generated switching signal to an antenna component so that the switching signal drives a switch in the antenna component; receiving at least a portion of a time-division multiplexed signal through a first correlator subchannel and a second correlator subchannel of the device, the time-division multiplexed signal being generated by the antenna component by periodically selecting a polarization signal from a first polarization signal and a second polarization signal; and The channel processes a right-hand circularly polarized (RHCP) signal by periodically switching the numerically controlled oscillator of the first correlator channel between 0° and +90° or between 0° and -90° at each switching time point of the first polarization signal and the second polarization signal; the second correlator sub-channel of the device processes a left-hand circularly polarized (LHCP) signal by periodically switching the numerically controlled oscillator of the second correlator channel between 0° and -90° or between 0° and +90° at each switching time point of the first polarization signal and the second polarization signal; and recombines the correlated RHCP signal and the LHCP signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic diagram illustrating a dual-feed antenna assembly consistent with some embodiments of the present disclosure.

[0009] Figure 2 is a schematic diagram illustrating an apparatus including an antenna assembly and a receiver consistent with some embodiments of the present disclosure.

[0010] Figure 3 is a schematic diagram illustrating a related post-recombination method consistent with some embodiments of the present disclosure.

[0011] Figure 4 is a schematic diagram illustrating a quad-feed antenna assembly consistent with some embodiments of the present disclosure.

[0012] Figure 5 is a flow chart illustrating an exemplary method for processing a signal consistent with some embodiments of the present disclosure.

[0013] Figure 6 is a block diagram of a device consistent with some embodiments of the present disclosure. DETAILED DESCRIPTION

[0014] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, in which, unless otherwise indicated, like reference numerals in different figures represent like or similar elements. The implementations set forth in the following description of the exemplary embodiments are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of systems, devices, and methods consistent with aspects related to the present disclosure as described in the appended claims.

[0015] Multipath interference causes serious problems in GNSS navigation solutions, especially in complex propagation environments (e.g., mountains, buildings, urban canyons, plants, etc.). GNSS satellites transmit right-hand circularly polarized (RHCP) electromagnetic waves. However, in complex propagation environments, the rotation direction of the electric field vector of the RHCP electromagnetic wave can change due to the interaction between the electromagnetic wave and the environment. For example, for an electromagnetic wave that hits a hard surface with an incident angle less than the Brewster's angle, the reflection of the hard surface changes the polarization direction of the electromagnetic wave. As a result, the RHCP electromagnetic wave may flip to a left-hand circularly polarized (LHCP) electromagnetic wave, and the GNSS receiver in a complex environment may receive the LHCP electromagnetic wave with a much stronger amplitude than in an open sky environment, resulting in serious problems in the GNSS navigation solution.

[0016] Spoofing attacks are another challenge in GNSS navigation solutions. For example, spoofed signals sent from unknown sources attempt to deceive GNSS receivers, making this a significant threat in autonomous vehicles that rely on trustworthy global location information.

[0017] Multipath interference and spoofing in GNSS receivers can be mitigated by adding hardware to the receiver's front end (e.g., using a multi-antenna array) and additional signal processing modules to the receiver's back end. However, this increases the size of the receiver and adds cost to the receiver design. Furthermore, using a multi-antenna array introduces operational complexity, for example, by requiring calibration of multiple antennas.

[0018] On the other hand, receivers using a single antenna typically use only RHCP signals. High-end receivers using expensive single antennas may be designed to use both RHCP and LHCP signals. However, receiver deployment is complex because it requires a hybrid coupler, two coaxial RF cables to transmit the RHCP and LHCP signals to the receiver, and two RF chains in the receiver to process the RHCP and LHCP signals. Furthermore, such receivers consume more power than standard receivers.

[0019] Embodiments of the present disclosure provide an apparatus including an antenna assembly and a receiver. In some embodiments, the antenna assembly includes an antenna including a first feed point that generates a first linearly polarized signal and a second feed point that generates a second linearly polarized signal. The antenna assembly further includes switching circuitry including a switch that periodically switches between the first feed point and the second feed point to select a polarization signal between the first linearly polarized signal and the second linearly polarized signal at a time point to form a time-division multiplexed signal. The multiplexed signal is then transmitted to a receiver. In some embodiments, the receiver includes a correlator including a plurality of correlator channels, each correlator channel being assigned to a different signal from a plurality of signals transmitted from a corresponding satellite from a plurality of satellites. Each of the plurality of correlator channels further includes a first subchannel and a second subchannel configured to process RHCP and LHCP signals, respectively. In some embodiments, the receiver determines a cross-polarization ratio (XPR) for each of the plurality of satellite signals to quantify the impact of multipath on each of the plurality of satellite signals, and de-weights one or more signals having an XPR value exceeding a threshold. In some embodiments, the receiver tracks both RHCP and LHCP signals. In some embodiments, the receiver quickly adjusts the number of channels and / or signals used for LHCP tracking during operation based on the need for critical measurements.

[0020] The embodiments disclosed in this disclosure have one or more technical effects. By switching between two different antenna feed points to time-division multiplex two signals with different linear polarization directions and processing the time-division multiplexed signals in the digital domain, the need for a 90° hybrid coupler, two RF cables, and two RF chains in the receiver is eliminated, thereby reducing size, cost, and power consumption. In addition, hybrid couplers can be temperature sensitive, so eliminating the need to use hybrid couplers makes operation unaffected by temperature fluctuations. Quantifying the multipath effects on each of multiple satellite signals based on XPR values and de-weighting one or more signals can improve measurement efficiency and effectiveness without increasing the size and cost of the receiver. Tracking both RHCP and LHCP signals enables assessment of the signal propagation environment and provides detailed information about the quality of the received signal at minimal cost. On the other hand, quickly adjusting the number of channels and / or signals used for LHCP tracking based on the need for multipath interference measurement can improve operational flexibility and reduce power consumption.

[0021] Figure 1 is a schematic diagram illustrating a dual-feed antenna assembly consistent with some embodiments of the present disclosure. Figure 1 , the device 100 includes an antenna assembly 110, which includes an antenna 112 and a switching circuit 130. The antenna 112 is configured to receive a GNSS signal 114. In one embodiment, the GNSS signal 114 may be a single satellite frequency band signal transmitted from a single satellite. In another embodiment, the GNSS signal 114 may include multiple satellite frequency band signals respectively transmitted from multiple satellites. In one embodiment, the GNSS signal 114 may include signals originating from one or more virtual sources that reflect and / or scatter the satellite signal. In one embodiment, the GNSS signal 114 may include a satellite signal refracted at an interface between two media. However, the signal received by the antenna 112 is not limited to a satellite signal, and may be any electromagnetic wave (e.g., a wireless cellular signal) transmitted from any source.

[0022] The antenna 112 includes a first feed point (not shown) that generates a first linearly polarized signal 116 and a second feed point (not shown) that generates a second linearly polarized signal 118. The first linearly polarized signal 116 and the second linearly polarized signal 118 are orthogonal in the xy direction, for example, Figure 11 and 10 (TM10) modes. In another embodiment, the first linearly polarized signal 116 and the second linearly polarized signal 118 form a ±45° system, where one of the two signals is polarized in the +45° direction and the other is polarized in the -45° direction. Antenna 112 can be any antenna having at least two internal ports (e.g., a patch antenna, a helical antenna, a cross-bow antenna, etc.).

[0023] The switching circuit 130 includes a switch 132 that periodically switches between the first feed point and the second feed point to select a polarization signal between the first linear polarization signal 116 and the second linear polarization signal 118 at a time point to form a time-division multiplexed signal. The time-division multiplexed signal is a combination of the sampled first linear polarization signal 116 and the sampled second linear polarization signal 118 forming a single signal path. The switching can be performed at a sufficiently high rate so that the sampled signal can be recovered by signal processing at the receiver. For example, the switching period can be less than 1 ms. The switching in the switch 132 is controlled by a switching signal, which can be a pulse signal or an alternating current (AC) signal. The details of the switching signal will be described below with respect to Figure 2 Provide a description.

[0024] The switching circuit 130 may include a switching signal detector 144 that detects the switching signal. The switching signal detector 144 may be selected based on the type of the switching signal. For example, if the switching signal consists of different amplitude levels, a comparator may be used as the switching signal detector 144.

[0025] By using a switch to switch between two different antenna feed points and time-division multiplexing two signals with different polarization directions, the need for a 90° hybrid coupler, two RF cables, and two RF chains in the receiver is eliminated, thereby reducing size, cost, and power consumption. In addition, hybrid couplers can be temperature sensitive, so eliminating the need to use a hybrid coupler makes operation unaffected by temperature fluctuations.

[0026] The switching circuit 130 may include a low noise amplifier (LNA) 134 coupled to the switch 132 and configured to amplify the time division multiplexed signal. The LNA 134 may be powered by a direct current (DC) bias, which will be discussed below with respect to FIG. Figure 2Detailed Description. In one embodiment, a low-pass filter (LPF) 142 may be implemented in the path of the DC bias so that switching signals superimposed on the DC bias can be filtered out before the DC bias is provided to the LNA 134. In one embodiment, the LNA 134 may include a controller to control parameters of the amplified signal. The parameters may include at least one of the following: gain, noise, linearity, bandwidth, output dynamic range, slew rate, rise rate, overshoot, or stability factor.

[0027] The switching circuit 130 may include a bandpass filter (BPF) 136 coupled to the LNA 134 and configured to filter the amplified signal to suppress frequencies outside of a range of interest. The filtered and amplified signal is then transmitted to a receiver via a cable 150, as described below with respect to Figure 2 The cable 150 may be a coaxial RF cable or any other cable suitable for transmitting RF signals.

[0028] The filtering and amplification of the time-division multiplexed signal performed on the antenna side and the digital signal processing performed on the receiver side result in an operation that is more immune to temperature drift.

[0029] In one embodiment, at least one of the LNA 134 and the BPF 136 may be implemented on the receiver side rather than on the antenna side. In another embodiment, both the antenna assembly 110 and the receiver may include an LNA and a BPF.

[0030] Figure 2 is a schematic diagram illustrating a device including an antenna assembly and a receiver consistent with some embodiments of the present disclosure. Figure 2 , the device 200 includes an antenna assembly 210, a receiver 260, and a cable 250 connecting the antenna assembly 210 and the receiver 260. The structure of the antenna assembly 210 is similar to Figure 1 The same components are denoted by the same reference numerals, and description thereof will not be repeated.

[0031] Receiver 260 includes a bias tee (bias T) circuit 272 that provides a DC bias signal. The DC bias signal is transmitted to LNA 134 of switching circuit 130 via cable 250.

[0032] The receiver 260 includes a switching signal generator 276 that generates a switching signal 138. The switching signal generator 276 can be a pulse signal generator or an AC signal generator. The switching signal 138 can be a synchronization signal formed by mixing the signal generated by the switching signal generator 276 with a local oscillation signal provided by a local oscillator (not shown). The switching period can be approximately 1 ms. The switching signal 138 is transmitted to the switching circuit 130 of the antenna assembly 210 via the cable 250, causing the switch 132 to switch between the first feed point and the second feed point of the antenna 112 under the control of the switching signal 138.

[0033] In one embodiment, the switching signal 138 may be a pulse signal including a positive pulse and a negative pulse. The first feed point of the antenna 112 may be provided with a positive pulse of the switching signal 138, while the second feed point of the antenna 112 may be provided with a negative pulse of the switching signal 138. Alternatively, the first feed point of the antenna 112 may be provided with a negative pulse of the switching signal 138, while the second feed point of the antenna 112 may be provided with a positive pulse of the switching signal 138. The length of the pulse may be approximately 100 μs or less, and the amplitude of the pulse may be approximately several volts.

[0034] In one embodiment, the DC bias signal provided by the bias-T circuit 272 and the switching signal 138 are superimposed and transmitted from the receiver 260 to the antenna assembly 210 via the same cable 250. In this case, a low-pass filter 142 that filters the switching signal 138 can be implemented in the path of the DC bias signal before providing it to the LNA 134.

[0035] The switching circuit 130 can perform time division multiplexing on the first polarization signal and the second polarization signal based on the switching signal 138. The time division multiplexing signal can be amplified by the LNA 134 and then filtered by the BPF 136. The amplified and filtered time division multiplexing signal is then transmitted to the receiver 260 via the cable 250 as Figure 2 Time division multiplexed (TDM) signal 274 in.

[0036] The receiver 260 includes a correlator 262. The correlator 262 includes a plurality of correlator channels starting from correlator channel 1 to correlator channel m and then to correlator channel n (not shown), where n is a natural number greater than 1. Each of the plurality of correlator channels is configured to receive a TDM signal 274. Each of the plurality of correlator channels also includes two subchannels. For example, correlator channel 1 includes subchannel 1 and subchannel 2. Similarly, correlator channel m includes subchannel 1 and subchannel 2. Each subchannel includes a numerically controlled oscillator (NCO) coupled to a mixer. The NCO may be a code generator NCO, which is configured to generate a signal in the frequency domain. Figure 22 is identified as a code NCO in the receiver 260. For example, subchannel 1 of correlator channel 1 includes code NCO 264 coupled to mixer 266, and subchannel 2 of correlator channel 1 includes code NCO 268 coupled to mixer 270. In each subchannel, a mixer mixes an incoming TDM signal 274 with a local oscillator signal generated by the NCO of that subchannel. Receiver 260 includes a processing engine 278. Processing engine 278 can be connected to each of the multiple correlator channels and control processing in each of the multiple correlator channels. In one embodiment, processing engine 278 can be implemented as software, and the operation of processing engine 278 can be implemented by a program stored in a computer-readable medium and executed by a processor. The processor can be implemented within receiver 260. In another embodiment, processing engine 278 can be implemented as hardware including a program and a processor configured to execute the program to perform the engine functions.

[0037] Subchannel 1 of each correlator channel forms a right-hand circularly polarized (RHCP) signal by periodically switching the NCO of the subchannel between 0° and +90° or between 0° and -90° at each switching time point between the first feed point and the second feed point of the antenna 112, thereby introducing a phase shift of +90° or -90° between the first linear polarization signal and the second linear polarization signal. Similarly, subchannel 2 of each correlator channel forms a left-hand circularly polarized (LHCP) signal by periodically switching the NCO of the subchannel between 0° and -90° or between 0° and +90° at each switching time point between the first antenna feed point and the second antenna feed point of the antenna 112, thereby introducing a phase shift of -90° or +90° between the first linear polarization signal and the second linear polarization signal.

[0038] For example, when subchannel 1 of correlator channel 1 forms an RHCP signal by periodically switching the NCO 264 of subchannel 1 between 0° and +90° at each switching time point of the first feed point and the second feed point of the antenna 112, subchannel 2 of correlator channel 1 forms an LHCP signal by periodically switching the NCO 268 of subchannel 2 of correlator channel 1 between 0° and −90° at each switching time point of the first antenna feed point and the second antenna feed point of the antenna 112. Similarly, when subchannel 1 of correlator channel 1 forms an RHCP signal by periodically switching the NCO 264 of subchannel 1 between 0° and −90° at each switching time point of the first antenna feed point and the second antenna feed point of the antenna 112, subchannel 2 of correlator channel 1 forms an LHCP signal by periodically switching the NCO 268 of subchannel 2 of correlator channel 1 between 0° and +90° at each switching time point of the first antenna feed point and the second antenna feed point of the antenna 112. In this way, a +90° or -90° phase shift is introduced between the first linearly polarized signal and the second linearly polarized signal without using a hardware component such as a 90° hybrid coupler.

[0039] Introducing a +90° or -90° phase shift between the first linearly polarized signal and the second linearly polarized signal in the digital domain, rather than using a hybrid coupler, ensures reduced size, cost, and power consumption, and enhanced immunity to temperature fluctuations.

[0040] In one embodiment, subchannel 1 and subchannel 2 of each of the multiple correlator channels can operate in a master-slave configuration. For example, subchannel 1 of correlator channel 1 can be configured as a master channel to process RHCP signals, while subchannel 2 of correlator channel 1 can be configured as a slave channel to process LHCP signals based on instructions from subchannel 1 of correlator channel 1. Similarly, subchannel 1 of correlator channel m can be configured as a master channel to process RHCP signals, while subchannel 2 of correlator channel m can be configured as a slave channel to process LHCP signals based on instructions from subchannel 1 of correlator channel m. In this configuration, tracking of the LHCP signal (e.g., phase, frequency, and code tracking) is guided by the RHCP master channel. For example, the receiver 260 can track only the RHCP signal and copy the local code and carrier timing tracked by the RHCP to the slave channel.

[0041] When the received GNSS signal includes multiple signals transmitted from multiple corresponding satellites, the master channel can quickly determine the number of multiple correlator channels and / or the number of multiple signals to be used for LHCP tracking based on the needs of evaluating key measurements. This enables real-time allocation of the number of channels and / or signals to be used for LHCP tracking, thereby improving system flexibility and reducing system power consumption.

[0042] In one embodiment, subchannel 1 and subchannel 2 of each of the plurality of correlator channels can operate in an independent configuration. For example, subchannel 2 can track the LHCP signal independently of the RHCP signal in subchannel 1. In one embodiment, a first portion of the plurality of correlator channels can operate in a master-slave configuration, while the remaining portions of the plurality of correlator channels can operate in an independent configuration.

[0043] Tracking both RHCP and LHCP signals enables assessment of the signal propagation environment and provides detailed information on the quality of the received signals.

[0044] Receiver 260 may be configured to calculate an XPR to quantify the impact of multipath interference. In one embodiment, the XPR may be calculated as the ratio of the power of the RHCP signal to the power of the LHCP signal. Receiver 260 may also use the calculated XPR to perform signal cluster analysis to detect the effects of spoofing.

[0045] In one embodiment, the GNSS signal 114 received by the antenna 112 includes multiple signals transmitted from multiple different satellites. In this embodiment, each of the multiple correlator channels (correlator channel 1 to correlator channel n) of the correlator 262 in the receiver 260 can be assigned to a different one of the multiple signals. Each of the multiple different satellite signals can have a corresponding one of multiple pseudo-random noise (PRN) codes, and each of the multiple satellite signals can be assigned to a different one of the multiple correlator channels based on the PRN code of the satellite signal. Each correlator channel can independently perform correlation of the signal received from the corresponding satellite. In this embodiment, the receiver 260 can be configured to calculate an XPR to quantify the impact of multipath interference on each of the multiple signals. The receiver 260 can further exclude one or more signals from the multiple signals whose XPR values exceed a threshold or de-weight the one or more signals from the multiple signals whose XPR values exceed the threshold. The receiver 260 can check the XPR values for some satellites; for example, one or more satellites commonly used for navigation can be checked more frequently than other satellites. In addition, one or more satellite signals affected by multipath interference can be selectively de-weighted based on the level of interference, thereby ensuring navigation accuracy. In this way, a single receiver can be used as a multi-GNSS constellation receiver, improving measurement efficiency and effectiveness without increasing the size and cost of the receiver.

[0046] In one embodiment, the processing engine 278 of the receiver 260 may perform reassembly of the associated RHCP and LHCP signals, such as with respect to Figure 3 described.

[0047] Figure 3 is a schematic diagram illustrating a method for post-correlation reassembly consistent with some embodiments of the present disclosure. Figure 2 The processing engine 278 in FIG306 is used to perform the post-correlation recombination. The processing engine combines the correlated first signal from the first polarization (shaded rectangle) in region 302 and the correlated second signal from the second polarization (shaded rectangle) in region 304. The incoming signal is shown in region 306, where the first group of blocks (the first shaded rectangle corresponding to the signal in region 302) illustrates the signal from the first polarization, and the second group of blocks (the second shaded rectangle corresponding to the signal in region 304) illustrates the signal from the second polarization. The switching signal is shown in region 306 as a continuous positive and negative binary signal. Both correlations occur in the same correlator channel and the results are buffered in two separate memory locations. The RHCP and LHCP signals are obtained by combining the outputs of these two signals with a phase shift of +90° or -90° between them. Figure 3, the time (t) axis at the top of the graph represents the processing time of the signal in the receiver. The points on the t axis represent the periods for correlating the incoming signal, with an integration time of 1 ms. For example, Figure 3 The period of the code bits for the Global Positioning System (GPS) L1 is shown (solid lines above and below the t-axis), with a period of 20 ms (the four points above the t-axis are omitted). The recombination of the correlation signals from the first and second polarizations can be performed at a later stage of the correlation operation or at the beginning of the code bit tracking operation. The incoming signal is amplified and Figure 3 310 . The processing engine of the receiver correlates the incoming time division multiplexed signals individually and generates a correlated first polarization signal in region 302 and a correlated second polarization signal in region 304 . The resulting correlated signals from the first polarization signal and the second polarization signal are summed independently, as represented by “+” (plus) symbols in regions 304 and 302 . As shown in operation 308 , the recombination is completed by adding a +90° (+j) or -90° (-j) phase shift to the two interleaved correlated signals to obtain correlated RHCP and LHCP signals. The switching period of the switching signal that controls the switching between the first polarization signal and the second polarization signal at the antenna assembly is less than the integration period at the receiver. For example, the switching period can be a fraction of the integration period at the receiver.

[0048] Figure 4 is a schematic diagram illustrating a quad-feed antenna assembly consistent with some embodiments of the present disclosure. Figure 4 , the device 400 includes an antenna assembly 410, which includes an antenna 412 and a switching circuit 430. The antenna 412 is configured to receive a GNSS signal 414. In one embodiment, the GNSS signal 414 may be a single satellite frequency band signal transmitted from a single satellite. In one embodiment, the GNSS signal 414 may include multiple satellite frequency band signals respectively transmitted from multiple satellites. In one embodiment, the GNSS signal 414 may include signals originating from one or more virtual sources that reflect and / or scatter the satellite signal. In one embodiment, the GNSS signal 414 may include a satellite signal refracted by an interface between two media. However, the signal received by the antenna 412 is not limited to a satellite signal, and may be any electromagnetic wave transmitted from any source.

[0049] Antenna 412 includes a first feed point (not shown) and a second feed point (not shown) that respectively generate a first linearly polarized signal 416 and a second linearly polarized signal 418. Antenna 412 also includes a third feed point (not shown) and a fourth feed point (not shown) that respectively generate a third linearly polarized signal 420 and a fourth linearly polarized signal 422. The first linearly polarized signal 416 and the second linearly polarized signal 418 can be polarized in the same direction. Figure 4 Similarly, the third linear polarization signal 420 and the fourth linear polarization signal 422 can be polarized in the same direction. Figure 4 The antenna 412 may be any antenna having at least four internal ports (e.g., a patch antenna, a helical antenna, a cross-bow antenna, etc.). Figure 4 Only two linearly polarized signals in each polarization direction are shown. However, the number of signals in each polarization direction is not limited thereto, and the number can be any number greater than 2.

[0050] Switching circuit 430 includes a hybrid coupler 442 that receives first linearly polarized signal 416 and second linearly polarized signal 418 and combines first linearly polarized signal 416 and second linearly polarized signal 418 to form a first combined polarized signal 446. Switching circuit 430 also includes a hybrid coupler 444 that receives third linearly polarized signal 420 and fourth linearly polarized signal 422 and combines third linearly polarized signal 420 and fourth linearly polarized signal 422 to form a second combined polarized signal 448. Hybrid coupler 442 and hybrid coupler 444 may be 180° hybrid couplers.

[0051] The switching circuit 430 includes a switch 432 that periodically switches between the first combined polarization signal 446 and the second combined polarization signal 448 to select the polarization signal between the two signals at a time point. The switching of the switch 432 is controlled by a switching signal. The switching signal is similar to the Figure 2 The switching signal 138 is described, and for the sake of brevity, a detailed description of the switching signal will be omitted here.

[0052] The switching circuit 430 may include a Figure 1 and Figure 2 The LNA 134 and BPF 136 include a low noise amplifier (LNA) 434 and a bandpass filter 436. For the sake of brevity, detailed descriptions of the LNA 434 and BPF 436 will be omitted. Utilizing multiple signals in each polarization direction can improve polarization purity.

[0053] By combining multiple signals provided by multiple corresponding feed points in each polarization direction, the polarization purity is improved, thereby improving the accuracy of operation.

[0054] Figure 5 is a flow chart illustrating an exemplary method 500 for processing a signal consistent with some embodiments of the present disclosure. The method may be performed by, for example, Figure 2 Executed by a device such as the device 200. Figure 5 , the method 500 includes a step S510 of generating a switching signal. For example, the switching signal may be generated by a Figure 2 The switching signal may be generated by a receiver such as a receiver 260 of the present invention. The switching signal may be a pulse signal or an AC signal. The switching signal may be synchronized by mixing with a local oscillator signal provided by a local oscillator. The switching signal may be transmitted from the receiver to an antenna assembly (such as a Figure 2 antenna assembly 210).

[0055] The method 500 includes a step S520 of time-division multiplexing the first polarization signal and the second polarization signal based on the switching signal. The time-division multiplexed signal can be formed by the antenna component by periodically switching between two feed points of the antenna that receives the GNSS signal and generates the first linear polarization signal and the second linear polarization signal respectively. The switching circuit of the antenna component (such as Figure 2 The switching circuit 130 of the receiver performs the switching based on the switching signal. The time-division multiplexed signal is sent to the receiver for processing. For example, the time-division multiplexed signal is sent to the correlator channel of the receiver (such as Figure 2 of the correlator channel 1 of the correlator 262).

[0056] The method 500 includes a step S530 of processing the RHCP signal. The processing of the RHCP signal may be performed by a first correlator subchannel of the receiver (such as, Figure 2 For example, at least a portion of the time-division multiplexed signal is received by a first correlator subchannel of the receiver, and the RHCP signal processing can be performed by periodically switching the NCO of the first correlator subchannel between 0° and +90° or between 0° and −90° at each switching point between the first polarization signal and the second polarization signal.

[0057] The method 500 includes a step S540 of processing the LHCP signal. The processing of the LHCP signal may be performed by a second correlator subchannel of the receiver (such as Figure 2The LHCP signal processing may be performed by correlator channel 1 (subchannel 2) of correlator 262 of the receiver. For example, at least a portion of the time-division multiplexed signal is received by a second correlator subchannel of the receiver, and processing of the LHCP signal may be performed by periodically switching the NCO of the second correlator subchannel between 0° and -90° or between 0° and +90° at each switching point between the first polarization signal and the second polarization signal. In one embodiment, step S540 may depend on step S530, such that step S530 determines whether to execute step S540 or how to execute step S540. In another embodiment, steps S530 and S540 may be executed independently.

[0058] The method 500 includes a step S550 of recombining the related RHCP and LHCP signals. The recombining may be performed by a processing engine of the receiver (such as, Figure 2 The processing engine 278 of the receiver 260 performs by interleaving the relevant RHCP and LHCP signals with a switching signal therebetween.

[0059] Figure 6 is a block diagram of an exemplary device 600 consistent with some embodiments of the present disclosure. Figure 6 Device 600 may take any form factor, including but not limited to a laptop computer, a GPS, a wireless terminal including a mobile phone, a wireless handheld device, or a wireless personal device, or any other form factor. Device 600 includes a receiver 602, an antenna 612 coupled to receiver 602, a processor 604, a memory 606, a local clock 608, and an input / output device 610.

[0060] Receiver 602, coupled to antenna 612, is configured to receive signals from one or more signal sources. In some embodiments, receiver 602 may be part of a transceiver modem that includes a transmitter configured to transmit data to an external device. Local clock 608 provides the time at the local location of device 600.

[0061] In one embodiment, similar to Figure 2 Receiver 260, receiver 602 may include a correlator including a plurality of correlator channels (not shown), such as, Figure 2 The correlator 262 includes a plurality of correlator channels, each of which may be assigned to a different signal from a plurality of signals transmitted from a corresponding satellite in the plurality of satellites. Each of the plurality of correlator channels may further include a first sub-channel and a second sub-channel, and the first sub-channel and the second sub-channel may be configured to process the RHCP signal and the LHCP signal, respectively.

[0062] The receiver 602 also includes a switching signal generator (such as a switching signal generator) that generates a switching signal. Figure 2 The receiver 602 may also include a processing engine (such as, Figure 2 The processing engine 278 may be implemented as a program stored in a computer-readable medium of the receiver. The receiver 602 may include a built-in processor (not shown) configured to execute the program and perform the functions of the processing engine. The receiver 602 may also include other components, such as a bias signal generator. For the sake of brevity, the description of these components is omitted here.

[0063] The processor 604 may include one or more dedicated processing units, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or various other types of processors or processing units. The processor 604 may be configured to perform some or all of the calculations in the digital domain signal processing. For example, the processor 604 may calculate a cross-polarization ratio (XPR) to estimate the effect of multipath interference and use the calculated XPR to perform signal clustering analysis to estimate the spoofing effect on each of a plurality of signals transmitted from a plurality of satellites. The processor 604 may be further configured to control the signal processing in the receiver 602. In one embodiment, the receiver 602 does not have a built-in processor, and the processor 604 performs all the functions of the built-in processor. In another embodiment, the device 600 does not have a processor 604, and the built-in processor of the receiver 602 performs all the functions of the processor 604.

[0064] Memory 606 can be any type of computer-readable storage medium, including volatile or non-volatile memory devices, or a combination thereof. Memory 606 can store information related to the identity of device 600 and GNSS signals received by receiver 602. Memory 606 can also store post-processed signals, including, for example, correlated RHCP and LHCP signals and signals obtained by recombining the correlated RHCP and LHCP signals. Memory 606 can also store computer-readable program instructions and mathematical models used for signal processing in receiver 602 and calculations performed in processor 604. Memory 606 can also store computer-readable program instructions for execution by the processor to operate device 600.

[0065] Input / output device 610 can be used to transmit the result of signal processing to a user or another device. Input / output device 610 may include a user interface, which includes a display and an input device for sending user commands to processor 604. The display can be configured to display the status of signal reception at display device 600, the data stored at memory 606, the status of signal processing, etc. The display may include, but is not limited to, a cathode ray tube (CRT), a liquid crystal display (LCD), a light emitting diode (LED), a gas plasma display, a touch screen, or other image projection devices for displaying information to the user. The input device can be any type of computer hardware device for receiving data and control signals from the user. The input device can include, but is not limited to, a keyboard, a mouse, a scanner, a digital camera, a joystick, a trackball, cursor direction keys, a touch screen monitor, or an audio / video commander, etc. The output device 610 may also include a machine interface, such as an electrical bus connection or a wireless communication link.

[0066] The computer-readable storage medium of the present disclosure may be a tangible device that can store instructions used by an instruction execution device. The computer-readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes the following: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device (such as a punch card or a raised structure in a groove having instructions recorded therein), and any suitable combination of the foregoing.

[0067] Computer readable program instructions of the present disclosure can be assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data or source code or object code written in any combination of one or more programming languages (including object-oriented programming languages and conventional process programming languages). The computer readable program instructions can be executed completely on a computing device as an independent software package, or partly on a first computing device and partly on a second computing device away from the first computing device. In the latter case, the second remote computing device can be connected to the first computing device through any type of network (including local area network (LAN) or wide area network (WAN)).

[0068] The flowcharts and block diagrams in the accompanying drawings illustrate examples of the architecture, functionality, and operation of possible implementations of systems, methods, and devices according to various embodiments. It should be noted that in some alternative implementations, the functions indicated in the blocks may not occur in the order indicated in the figures. For example, depending on the functionality involved, two blocks shown in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order.

[0069] It should be understood that the described embodiments are not mutually exclusive, and elements, components, materials, or steps described in conjunction with one example embodiment may be combined with or removed from other embodiments in a suitable manner to achieve desired design goals.

[0070] Reference herein to "some embodiments" or "some exemplary embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment. The appearance of the phrases "one embodiment," "some embodiments," or "another embodiment" in various places in this disclosure does not necessarily all refer to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

[0071] It should be understood that the steps of the example methods set forth herein are not necessarily required to be performed in the order described, and the order of the steps of such methods should be understood to be merely illustrative. For example, depending on the functionality involved, two blocks shown in succession may actually be performed substantially simultaneously, or the blocks may sometimes be performed in the reverse order. Likewise, in methods consistent with various embodiments, additional steps may be included in such methods, and certain steps may be omitted or combined.

[0072] As used in this disclosure, the word "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, the use of this word is intended to present concepts in a concrete manner.

[0073] As used in this disclosure, unless expressly stated otherwise, the term "or" encompasses all possible combinations unless not feasible. For example, if it is stated that a database may include either A or B, then unless expressly stated otherwise or not feasible, the database may include either A, or B, or A and B. As a second example, if it is stated that a database may include either A, B, or C, then unless expressly stated otherwise or not feasible, the database may include either A, or B, or C, or A and B, or A and C, or B and C, or A, B, and C.

[0074] In addition, the articles "a" and "an" as used in this disclosure and the appended claims should generally be construed to mean "one or more" unless specified otherwise or clear from context to dictate a singular form.

[0075] Unless expressly stated otherwise, each numerical value and range should be interpreted as approximations as if the value or range were preceded by the word "about" or "approximately."

[0076] Although elements in the following method claims, if any, are listed in a specific order, those elements are not necessarily intended to be limited to implementation in that specific order unless the claim recitation implies a specific order for implementing some or all of those elements.

[0077] It should be understood that certain features of the present disclosure that are described in the context of separate embodiments for clarity may also be provided in combination in a single embodiment. Conversely, for brevity, multiple features of this specification that are described in the context of a single embodiment may also be provided individually or in any suitable subcombination or as appropriate in any other described embodiment of this specification. Unless otherwise indicated, certain features described in the context of various embodiments are not essential features of those embodiments.

[0078] It will also be understood that those skilled in the art may make various modifications, substitutions and changes to the details, materials and arrangements of the parts described and illustrated without departing from the scope of the present invention to explain the nature of the described embodiments. Therefore, the appended claims cover all such substitutions, modifications and changes that fall within the scope of the claims.

Claims

1. A device using a dual-polarized antenna, the device comprising: An antenna assembly, the antenna assembly comprising: an antenna configured to receive a signal and, based on the received signal, generate a first linearly polarized signal at a first feed point and a second linearly polarized signal at a second feed point; a switching circuit configured to periodically switch between the first feeding point and the second feeding point based on a switching signal to select a polarization signal between the first linear polarization signal and the second linear polarization signal at a point in time; a receiver coupled to receive the selected polarization signal, the receiver configured to: processing the selected polarization signal to generate at least a right-hand circularly polarized (RHCP) signal; and generating the switching signal; and a cable coupling the antenna assembly and the receiver and configured to: transmitting the selected polarization signal from the antenna assembly to the receiver; and The generated switching signal is transmitted from the receiver to the antenna assembly.

2. The device according to claim 1, wherein: The switching signal is a signal synchronized with the oscillation signal and controls the switch in the switching circuit to switch between the first feeding point and the second feeding point, and The switching circuit is configured to time-division multiplex the first linear polarization signal and the second linear polarization signal based on a synchronized switching signal.

3. The device according to claim 2, wherein The receiver comprises: a correlator comprising a plurality of correlator channels, each correlator channel being configured to receive a time division multiplexed signal, Each of the plurality of correlator channels further comprises a first sub-channel and a second sub-channel, and each of the first sub-channel and the second sub-channel comprises a digitally controlled oscillator coupled to a mixer.

4. The device according to claim 3, wherein: The signal received by the antenna includes a plurality of signals respectively transmitted from a plurality of different satellites, and Each correlator channel of the plurality of correlator channels is assigned to a different signal of the plurality of signals.

5. The apparatus according to claim 3, wherein: The first sub-channel is configured to process a right-hand circularly polarized (RHCP) signal by periodically switching the digitally controlled oscillator of the first sub-channel between 0° and +90° or between 0° and -90° at each switching time point of the first feeding point and the second feeding point, and The second sub-channel is configured to process a left-hand circularly polarized (LHCP) signal by switching the numerically controlled oscillator of the second sub-channel between 0° and −90° or between 0° and +90° at each switching time point between the first feeding point and the second feeding point.

6. The device according to claim 5, wherein: The first sub-channel and the second sub-channel are configured as a master channel and a slave channel respectively, The first subchannel is configured to process the RHCP signal, and The second subchannel is configured to process the LHCP signal based on an instruction of the first subchannel.

7. The device according to claim 5, wherein Processing the RHCP signal by the first sub-channel and processing the LHCP signal by the second sub-channel are performed independently.

8. The device according to claim 5, wherein Each correlator channel of the plurality of correlator channels further comprises: A processing engine combines the correlated RHCP signal and the correlated LHCP signal by interleaving the correlated RHCP signal and the correlated LHCP signal with a switching signal therebetween.

9. The device according to claim 3, wherein The receiver further comprises: A switching signal generator is configured to generate a pulse signal including a positive pulse and a negative pulse as the switching signal.

10. The device according to claim 9, wherein The first feed point of the antenna is supplied with the positive pulse of the switching signal, and the second feed point of the antenna is supplied with the negative pulse of the switching signal.

11. The apparatus according to claim 1 , wherein: The antenna assembly further includes: an amplifier configured to amplify the selected polarization signal; and a filter configured to receive the amplified signal and filter the amplified signal, and The receiver further comprises: A bias circuit is configured to provide a direct current (DC) bias to the amplifier of the antenna assembly.

12. The device according to claim 1, wherein The signal received by the antenna includes a Global Navigation Satellite System (GNSS) signal, and the first linear polarization signal and the second linear polarization signal are in two different orthogonal modes.

13. A method of operating a device, wherein: The apparatus includes: a receiver configured to generate a switching signal; an antenna configured to receive a signal and generate a first linear polarization signal and a second linear polarization signal having different polarization directions; and a cable coupling the antenna and the receiver and configured to transmit a time-division multiplexed signal from the antenna to the receiver and to transmit the generated switching signal from the receiver to the antenna. The method includes: generating the switching signal; transmitting the switching signal from the receiver to the antenna via the cable; Based on the switching signal, time-division multiplexing the first linear polarization signal and the second linear polarization signal using a switch included in the antenna to provide the time-division multiplexed signal; transmitting the time-division multiplexed signal from the antenna to the receiver via the cable; Receiving at least a portion of the time-division multiplexed signal by a first correlator subchannel and a second correlator subchannel; The first correlator subchannel processes a right-hand circularly polarized (RHCP) signal by periodically switching a digitally controlled oscillator of the first correlator subchannel between 0° and +90° or between 0° and −90° at each switching time point between the first linearly polarized signal and the second linearly polarized signal; processing a left-hand circularly polarized (LHCP) signal by the second correlator subchannel by periodically switching a numerically controlled oscillator of the second correlator subchannel between 0° and −90° or between 0° and +90° at each switching point between the first linearly polarized signal and the second linearly polarized signal; and The correlated RHCP signal and the LHCP signal are recombined.

14. The method according to claim 13, wherein The signal received by the antenna includes a plurality of signals transmitted from a plurality of satellites and corresponding to a plurality of satellite frequency bands, respectively. The method further includes: calculating a cross-polarization ratio (XPR) to quantify the effect of multipath on each of the plurality of signals; and One or more signals from the plurality of signals having an XPR value exceeding a threshold are excluded.

15. The method according to claim 13, wherein The signal received by the antenna includes a plurality of signals transmitted from a plurality of satellites and corresponding to a plurality of satellite frequency bands, respectively. The method further includes: A cross-polarization ratio (XPR) is calculated, and a signal cluster analysis is performed using the calculated XPR to detect spoofing on each of the plurality of signals.

16. A non-transitory computer-readable medium having instructions stored therein, wherein when the instructions are executed by a processor, a method for controlling a device is performed, the method comprising: generating a switching signal by the device; sending the generated switching signal to the antenna assembly via the cable so that the switching signal drives a switch in the antenna assembly; receiving, by a first correlator sub-channel and a second correlator sub-channel of the device via the cable, at least a portion of a time-division multiplexed signal, the time-division multiplexed signal being generated by the antenna assembly by periodically selecting a polarization signal from a first polarization signal and a second polarization signal; The first correlator subchannel of the device processes a right-hand circularly polarized (RHCP) signal by periodically switching a digitally controlled oscillator of the first correlator subchannel between 0° and +90° or between 0° and −90° at each switching time point of the first polarized signal and the second polarized signal; Processing a left-hand circularly polarized (LHCP) signal by the second correlator subchannel of the device by periodically switching a numerically controlled oscillator of the second correlator subchannel between 0° and −90° or between 0° and +90° at each switching point between the first polarization signal and the second polarization signal; and The correlated RHCP signal and the LHCP signal are recombined.

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