Polarization configurable GNSS smartphone antenna

Abstract

A Global Navigation Satellite System (GNSS) receiver for a portable device includes a first linearly polarized antenna configured to receive a first linearly polarized component of a GNSS signal, a second linearly polarized antenna configurable to receive a second linearly polarized component of the GNSS signal, a radio frequency signal conforming to a second wireless communication technology, or both, and a hybrid coupler that combines the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal to generate a circularly polarized GNSS signal. In some embodiments, the GNSS receiver includes a tuner for tuning a resonant frequency of the second linearly polarized antenna. In some embodiments, the GNSS receiver includes a switch or filter for connecting or disconnecting the second linearly polarized antenna to or from the hybrid coupler to implement a circularly polarized antenna or a linearly polarized antenna.

Description

[Technical field]

[0001] The present invention relates to a polarization configurable GNSS smartphone antenna. [Background technology]

[0002] Obtaining a reliable and accurate location of a mobile device or system can be useful for many applications, such as emergency response, personal navigation, autonomous driving, asset tracking, locating friends or family, etc. Mobile device positioning techniques include measuring radio signals transmitted from various devices or entities, including satellite vehicles (SVs) and terrestrial radio sources in wireless networks, such as base stations and access points. For example, modern electronic devices often include systems that can receive signals from satellite navigation systems, commonly referred to as global navigation satellite systems (each "GNSS"), and use the satellite signals to determine the location of the device and other information, such as speed, orientation, altitude, etc. GNSS receivers can be incorporated into portable consumer electronic devices, such as smartphones or smartwatches, as well as into navigation systems in various types of vehicles, such as automobiles, trucks, ships, aircraft, and drones. Signals from multiple satellites orbiting the Earth can be received and processed by the GNSS receiver to determine the location of the GNSS receiver and to surrogately determine the location of the device, vehicle, user, etc. Summary of the Invention [Means for solving the problem]

[0003] The techniques disclosed herein relate generally to Global Navigation Satellite System (GNSS) antennas, and more particularly to circularly polarized and polarization configurable GNSS antennas for smartphones or other portable devices. Various inventive embodiments are described herein, including devices, systems, components, apparatus, methods, procedures, instructions, code, computer storage media, and the like.

[0004] According to some embodiments, a GNSS receiver for a portable device (e.g., a smartphone) may include a first linearly polarized antenna configured to receive a first linearly polarized component of a GNSS signal (i.e., a radio frequency signal conforming to a first wireless communication technology), a second linearly polarized antenna configurable to receive a second linearly polarized component of the GNSS signal, a radio frequency signal conforming to a second wireless communication technology, or both, and a hybrid coupler. The hybrid coupler may include a first port electrically coupled to the first linearly polarized antenna, a second port electrically coupled to the second linearly polarized antenna, and a third port outputting a combined GNSS signal of the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal, wherein a difference between a phase delay from the second port to the third port and a phase delay from the first port to the third port is between about 60° and about 120°.

[0005] In some embodiments of the GNSS receiver, the first linearly polarized antenna and the second linearly polarized antenna may be planar inverted F-antennas. The first linearly polarized antenna may also be configured to receive radio frequency signals conforming to a third wireless communication technology, and the GNSS receiver may include a demultiplexing circuit coupled to the first linearly polarized antenna and configured to separate the first linearly polarized component of the GNSS signal and the radio frequency signal conforming to the third wireless communication technology. The demultiplexing circuit may include, for example, an n-plexer, where n is greater than 1. In one example, the demultiplexing circuit may include a first bandpass filter configured to select the first linearly polarized component of the GNSS signal and a second bandpass filter configured to select the radio frequency signal conforming to the third wireless communication technology.

[0006] In some embodiments of the GNSS receiver, the second linearly polarized antenna may include a tuner configured to tune a resonant frequency of the second linearly polarized antenna to receive the second linearly polarized component of the GNSS signal, the radio frequency signal compliant with the second wireless communication technology, or both. The tuner may include, for example, an aperture tuner or an impedance tuner. In some embodiments, the GNSS receiver may include a switch between the second linearly polarized antenna and the second port of the hybrid coupler to connect or disconnect the second linearly polarized antenna and the hybrid coupler. In some embodiments, the GNSS receiver may include an n-plexer between the second linearly polarized antenna and the second port of the hybrid coupler to separate the second linearly polarized component of the GNSS signal and the radio frequency signal compliant with the second wireless communication technology and then send the second linearly polarized component of the GNSS signal to the second port of the hybrid coupler. In some embodiments, the GNSS receiver may include an n-plexer coupled to a third port of the hybrid coupler and configured to separate the GNSS L1 signal and the GNSS L5 signal.

[0007] The second wireless communication technology may include, for example, a wireless wide area network (WWAN) technology, a wireless local area network (WLAN) technology, or a wireless personal area network (WPAN) technology. In some embodiments, the first linearly polarized antenna may include a vertical linearly polarized antenna, and the second linearly polarized antenna may include a horizontal linearly polarized antenna. The third port of the hybrid coupler may output a right-hand circularly polarized GNSS signal.

[0008] According to some embodiments, the method may include receiving a first linearly polarized component of the GNSS signal by a first antenna of the portable device, tuning a second antenna of the portable device to a GNSS band, receiving a second linearly polarized component of the GNSS signal by the tuned second antenna, and combining the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal by a hybrid coupler (e.g., a hybrid coupler having a nominal phase shift of 90°) to generate a composite GNSS signal (e.g., a circularly polarized GNSS signal).

[0009] In some embodiments, the method may also include tuning the second antenna to a frequency band for a second wireless communication technology different from the GNSS technology, disconnecting the second antenna from the hybrid coupler by a switch or filter, and providing the composite GNSS signal or the first linearly polarized component of the GNSS signal to a radio frequency front-end circuit of the portable device. The second wireless communication technology may include, for example, a Wireless Wide Area Network (WWAN) technology, a Wireless Local Area Network (WLAN) technology, or a Wireless Personal Area Network (WPAN) technology.

[0010] In some embodiments, tuning the second antenna may include tuning the second antenna to receive both the second linearly polarized component of the GNSS signal and the radio frequency signal compliant with the second wireless communications technology, and the method may include separating the second linearly polarized component of the GNSS signal and the radio frequency signal compliant with the second wireless communications technology.

[0011] In some embodiments, the method may include receiving, by a first antenna, a radio frequency signal conforming to a third wireless communication technology, and separating the first linearly polarized component of the GNSS signal and the radio frequency signal conforming to the third wireless communication technology. The third wireless communication technology may include, for example, a wireless wide area network (WWAN) technology, a wireless local area network (WLAN) technology, or a wireless personal area network (WPAN) technology.

[0012] In some embodiments, combining the first linearly polarized component of the GNSS signal with the second linearly polarized component of the GNSS signal may include delaying the second linearly polarized component of the GNSS signal by a phase delay within +90±30° or within −90±30° relative to the first linearly polarized component of the GNSS signal. In some embodiments, the method may include automatically switching a switch between the second antenna and the hybrid coupler to connect or disconnect the second antenna and the hybrid coupler based on environmental conditions, operating conditions, or both of the portable device.

[0013] In some embodiments, the method may include disconnecting the second antenna from the hybrid coupler, measuring a first set of one or more GNSS signals using the first antenna, connecting the second antenna to the hybrid coupler, measuring a second set of one or more GNSS signals using the first antenna and the second antenna, and identifying GNSS signals that are in the first set of one or more GNSS signals but not in the second set of one or more GNSS signals as multipath GNSS signals. In some embodiments, the method may also include identifying a first satellite associated with the multipath GNSS signals. In some embodiments, the method may further include disconnecting the second antenna from the hybrid coupler, measuring a third set of GNSS signals using the first antenna, including the GNSS signals from the first satellite, and determining a location fix based on the third set of GNSS signals excluding the GNSS signals from the first satellite.

[0014] According to some embodiments, the portable device may include means for receiving a first linearly polarized component of the GNSS signal, means for tuning an antenna of the portable device to a GNSS band to receive a second linearly polarized component of the GNSS signal, and means for combining the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal to generate a circularly polarized GNSS signal.

[0015] In some embodiments, the portable device may also include means for tuning the antenna to a frequency band for a second wireless communication technology, means for disconnecting the antenna from the means for combining the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal, and means for providing the first linearly polarized component of the GNSS signal or the circularly polarized GNSS signal to a radio frequency front-end circuit of the portable device. In some embodiments, the second wireless communication technology may include a wireless wide area network (WWAN) technology, a wireless local area network (WLAN) technology, or a wireless personal area network (WPAN) technology.

[0016] In some embodiments, the means for tuning the antenna may include means for tuning the antenna to both the GNSS band and a frequency band for a second wireless communication technology, and the portable device may further include means for separating a second linearly polarized component of the GNSS signal and a radio frequency signal compliant with the second wireless communication technology. In some embodiments, the means for receiving a first linearly polarized component of the GNSS signal may be further configured to receive a radio frequency signal compliant with the second wireless communication technology, and the portable device may include means for separating the first linearly polarized component of the GNSS signal and a radio frequency signal compliant with the second wireless communication technology.

[0017] According to some embodiments, the GNSS receiver may include a first linearly polarized antenna configured to receive a first linearly polarized component of the GNSS signal, a second linearly polarized antenna, a tuner configurable to tune the second linearly polarized antenna to a GNSS band to receive the second linearly polarized component of the GNSS signal, and a hybrid coupler (e.g., a 90° hybrid coupler) configured to combine the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal to generate a circularly polarized GNSS signal.

[0018] In some embodiments of the GNSS receiver, the tuner may be configurable to tune the second linearly polarized antenna to a frequency band for a second wireless communications technology, and the GNSS receiver may include a switch or filter configured to disconnect the second linearly polarized antenna from the hybrid coupler.

[0019] In some embodiments, the tuner may be configurable to tune the second linearly polarized antenna to receive both the second linearly polarized component of the GNSS signal and the radio frequency signal compliant with the second wireless communication technology, and the GNSS receiver may include an n-plexer configured to separate the second linearly polarized component of the GNSS signal and the radio frequency signal compliant with the second wireless communication technology.

[0020] In some embodiments, the first linearly polarized antenna may be configured to receive a radio frequency signal conforming to a second wireless communication technology, and the GNSS receiver may include an n-plexer configured to separate the first linearly polarized component of the GNSS signal and the radio frequency signal conforming to the second wireless communication technology.

[0021] This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used alone to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification, any or all drawings, and appropriate portions of each claim of this disclosure. The above, together with other features and examples, are described in more detail below in the following specification, claims, and accompanying drawings.

[0022] Aspects of the present disclosure are illustrated by way of example, non-limiting and non-exhaustive aspects with reference to the following figures. [Brief description of the drawings]

[0023] [Figure 1] 1 is a simplified diagram of an example of a positioning system, according to some embodiments. [Diagram 2] FIG. 1 illustrates an example frequency band for a global navigation satellite system. [Diagram 3] FIG. 1 is a simplified block diagram of an example Global Navigation Satellite System (GNSS) receiver. [Figure 4A] FIG. 2 illustrates an example of a radio frequency antenna in an example smartphone. [Figure 4B] FIG. 1 illustrates an example of a radio frequency antenna including a planar inverted-F antenna (PIFA). [Figure 5A] FIG. 2 illustrates the rotation of the electric field vector of an example circularly polarized electrical signal. [Figure 5B] 1A and 1B are diagrams illustrating examples of signals characterized by left-handed or right-handed circular polarization. [Figure 6A] FIG. 2 illustrates an example of a circularly polarized GNSS antenna, according to some embodiments. [Figure 6B] FIG. 1 illustrates an example of a 90° hybrid coupler. [Figure 7] FIG. 2 illustrates another example of a circularly polarized GNSS antenna, according to some embodiments. [Figure 8] FIG. 1 illustrates an example of a polarization configurable GNSS smartphone antenna, according to some embodiments. [Figure 9] 1 is a flowchart illustrating an example of a method for configuring a polarization configurable GNSS receiver according to some embodiments. [Figure 10] FIG. 1 illustrates an example of a user equipment (UE) in accordance with some embodiments. [Figure 11] FIG. 2 illustrates an example of a transmit receiving point (TRP) according to some embodiments. [Figure 12] FIG. 1 is a block diagram of an example computer system, according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] In the figures, like reference numbers refer to like parts throughout the various figures unless otherwise specified. In addition, multiple instances of a component may be distinguished by following the reference number with a second label (e.g., a letter or number), or a dash and a second label. If only a first reference label is used herein, the description is applicable to any one of the like components having the same first reference number, regardless of the second label.

[0025] The techniques disclosed herein relate generally to Global Navigation Satellite System (GNSS) antennas, and more particularly to circularly polarized and polarization configurable GNSS antennas for smartphones or other portable devices. Various inventive embodiments are described herein, including devices, systems, components, apparatus, methods, procedures, instructions, code, computer-readable storage media, and the like.

[0026] More and more users around the world are turning to mobile navigation services because knowing the location of a moving object, such as a mobile device or system, can be very useful for many applications and / or in many situations, such as emergency calls, personal navigation, autonomous driving, asset tracking, human location, etc. Many mobile electronic devices include systems that can receive satellite signals from a GNSS system and use the satellite signals to determine the location of the device and other information, such as speed, orientation, altitude, etc. GNSS receivers can be incorporated into consumer electronic devices, such as smartphones or smart watches. Signals from multiple satellites orbiting the Earth can be received and processed by the GNSS receiver to determine the location of the GNSS receiver based on the known locations of the multiple satellites and the distance between the GNSS receiver and each of the multiple satellites.

[0027] GNSS satellites, such as Global Positioning System (GPS) satellites, generally employ right-hand circular polarization (RHCP) to transmit signals to the Earth. Planar inverted F antennas (PIFAs) are commonly used in smartphones to receive GNSS signals because they can be manufactured to comply with industrial design and fit the compact design of smartphones or other portable devices. However, PIFAs in smartphones are generally linearly polarized antennas. Since the GNSS signals transmitted by the satellites are right-hand circularly polarized, but the receiving PIFA antennas are linearly polarized antennas, there may be as much as 3 dB loss in signal level due to polarization mismatch. In addition, in a multipath environment, the polarization of the satellite signal changes from RHCP to left-hand circularly polarized (LHCP) or from LHCP to RHCP with each reflection. Thus, the satellite signal may be an RHCP signal if the satellite signal does not reflect or if the satellite signal reflects an even number of times, and may be an LHCP signal if the satellite signal reflects an odd number of times. In some cases, the reflected GNSS signal may be an elliptically polarized signal or a signal with other polarization states. Thus, the term "GNSS signal" as used herein refers to any radio frequency signal that conforms to GNSS technology and has any polarization state, including linear, circular, elliptical, or unpolarized. Both line-of-sight and reflected signals may be received by a GNSS receiver, but may not be in phase. A linearly polarized antenna may not be able to distinguish between line-of-sight and reflected signals, which may cause positioning errors.

[0028] The RHCP GNSS antenna can receive the RHCP GNSS signal more efficiently with little loss caused by polarization mismatch. In addition, the RHCP GNSS antenna can reject reflected GNSS signals that may be LHCP due to reflections. Therefore, the right-handed circularly polarized antenna is less susceptible to multipath signals compared to a linearly polarized antenna that can accept both right-handed and left-handed circularly polarized signals.

[0029] However, designing a circularly polarized antenna for use in a smartphone can be difficult due to limitations in physical dimensions and printed circuit board (PCB) area, PCB shape constraints (e.g., caused by industrial design, battery size, etc.), and limited freedom in antenna placement. Most smartphones have multi-layer PCBs with multiple layers of metal planes (e.g., copper). Integrated circuits (ICs) placed on the PCB and interconnect traces routed on the PCB may use several copper cutouts. Due to these constraints, it can be very difficult to modify the ground plane and excite currents on the ground plane to achieve circular polarization with an axial ratio close to 0 dB. For example, although an RHCP antenna can be formed using a patch antenna, the area used for the patch antenna and the ground clearance on the PCB for the patch antenna may not be practical in a smartphone design.

[0030] According to some embodiments, a GNSS antenna in a smartphone or another portable device (e.g., a smartwatch) may include two or more linear antennas (e.g., PIFAs) and a hybrid coupler coupled to the two or more linear antennas. The phase shift of the hybrid coupler may be any suitable value, such as any value between about 90°±60°, between about 90°±45°, between about 90°±30°, between about 90°±15°, between about 90°±10°, or between about 90°±5°. In one example, the nominal phase shift of the hybrid coupler may be 90° (which may be referred to as a 90° hybrid coupler or combiner), however, the actual phase shift may be, for example, between about 90°±45°, between about 90°±30°, between about 90°±15°, between about 90°±10°, between about 90°±5°, or between about 90°±2°. The 90° hybrid coupler may combine linearly polarized signals received by two linear antennas that may already be used in a smartphone for other purposes (e.g., cellular or other wireless communications) to implement an RHCP GNSS antenna with improved signal power and multipath rejection (e.g., by about 3 dB). In some embodiments, two or more antennas may be tuned to optimize antenna usage. For example, two or more antennas may be dynamically configured and / or tuned to become RHCP (for receiving RHCP GNSS signals) or to maintain linear polarization, thus allowing a user to select an operating mode based on the environment and desired accuracy. As a result, the GNSS receiver may be able to determine a position fix with excellent accuracy in many conditions using a linearly polarized antenna, and may be able to achieve more accurate position fixes in more open / favorable environments by replicating a circularly polarized antenna.

[0031] The terms "user equipment" (UE) and "base station" as used herein are not intended to be specific or otherwise limited to a particular radio access technology (RAT) unless otherwise stated. In general, a UE may be any wireless communication device (e.g., a mobile phone, a router, a tablet computer, a laptop computer, a tracking device, a wearable (e.g., a smart watch, glasses, an augmented reality (AR) / virtual reality (VR) headset, etc.), a vehicle (e.g., an automobile, a motorcycle, a bicycle, etc.), an Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communication network. A UE may be mobile or stationary (e.g., at some time) and may communicate with a radio access network (RAN). The term "UE" as used herein may be referred to interchangeably as an "access terminal" or "AT", "client device", "wireless device", "subscriber device", "subscriber terminal", "subscriber station", "user terminal" (or UT), "mobile device", "mobile terminal", "mobile station", or variations thereof. In general, a UE may communicate with a core network via the RAN, through which the UE may be connected to external networks (such as the Internet) and to other UEs. Other mechanisms for connecting to the core network and / or the Internet are also possible for a UE, such as via a wired access network, a wireless local area network (WLAN) network (e.g., based on IEEE 802.11, etc.).

[0032] A base station may operate according to one of several RATs in communication with a UE depending on the network in which the base station is deployed and may alternatively be referred to as an access point (AP), network node, Node B, evolved Node B (eNB), next generation eNB (ng-eNB), new radio (NR) Node B (also referred to as gNB or gNode B), etc. In an NR system, the terms "cell" and next generation Node B (gNB), new radio base station (NR BS), 5G NB, access point (AP), or transmit reception point (TRP) may be used interchangeably. A base station may be primarily used to support wireless access by UEs, including supporting data, voice, and / or signaling connections for supported UEs. In some systems, a base station may provide purely edge node signaling functions, while in other systems, a base station may provide additional control and / or network management functions. A communication link through which a UE may send signals to a base station is referred to as an uplink (UL) channel (e.g., reverse traffic channel, reverse control channel, access channel, etc.). A communication link through which a base station may send signals to a UE is called a downlink (DL) or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein, the term Traffic Channel (TCH) can refer to either an uplink / reverse traffic channel or a downlink / forward traffic channel.

[0033] In some embodiments, the term "base station" may refer to a single physical transmit reception point (TRP) or multiple physical TRPs that may or may not be collocated. For example, when the term "base station" refers to a single physical TRP, the physical TRP may be an antenna of the base station corresponding to a cell (or several cell sectors) of the base station. When the term "base station" refers to multiple collocated physical TRPs, the physical TRP may be an array of antennas of the base station (e.g., as in the case of a multiple-input multiple-output (MIMO) system or when the base station employs beamforming). When the term "base station" refers to multiple non-collocated physical TRPs, the physical TRP may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transport medium) or a remote radio head (RRH) (a remote base station connected to a serving base station). Alternatively, a non-collocated physical TRP may be a serving base station from which the UE receives measurement reports from neighboring base stations whose UE is measuring its reference RF signal (or simply "reference signal"). A TRP is a point from which a base station transmits and receives wireless signals, so as used herein, references to transmission from or reception at a base station should be understood as referring to the particular TRP of the base station.

[0034] In some implementations that support positioning of UEs, a base station may not support wireless access by the UE (e.g., may not support data, voice, and / or signaling connections for the UE), but instead may transmit reference signals to the UE to be measured by the UE and / or may receive and measure signals transmitted by the UE. Such a base station may be referred to as a positioning beacon (e.g., when it transmits signals to the UE) and / or a location measurement unit (e.g., when it receives and measures signals from the UE).

[0035] An "RF signal" includes electromagnetic waves in a given frequency range that transport information through space between a transmitter and a receiver. As used herein, a transmitter may transmit a single RF signal or multiple RF signals to a receiver. However, the receiver may receive multiple RF signals corresponding to each transmitted RF signal due to the propagation characteristics of RF signals through a multipath channel. The same RF signal transmitted on different paths between a transmitter and a receiver may be referred to as a multipath RF signal. As used herein, an RF signal may also be referred to as a "wireless signal" or simply a "signal" when it is clear from the context that the term "signal" refers to a wireless signal or an RF signal.

[0036] A "space vehicle" or "SV," as referred to herein, relates to an object capable of transmitting a signal to a receiver on the Earth's surface. In one particular example, such an SV may include a geostationary satellite. Alternatively, an SV may include a satellite that travels in an orbit and moves relative to a fixed location on the Earth. However, these are merely examples of SVs and claimed subject matter is not limited in these respects.

[0037] "Location," as referred to herein, relates to information associated with the whereabouts of an object or thing according to a reference point. For example, such location may be represented as geographic coordinates, such as latitude and longitude. In another example, such location may be represented as earth-centered XYZ coordinates. In yet another example, such location may be represented as a street address, a municipality or other governmental jurisdiction, a zip code, and the like. However, these are merely examples of how location may be represented according to certain examples and claimed subject matter is not limited in these respects. "Location" may also be referred to herein as a "location estimate," "estimated location," "location," "position," "position estimate," "position fix," "estimated position," "location fix," or "fix."

[0038] Some exemplary embodiments will now be described with reference to the accompanying drawings that form a part of this specification. The following description provides only embodiments and is not intended to limit the scope, applicability, or configuration of the present disclosure. Rather, the following description of the embodiments provides those skilled in the art with an enabling description for implementing one or more embodiments. It should be understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the present disclosure. In some instances, devices, systems, structures, assemblies, methods, and other components may be shown as components in block diagram form so as not to obscure the examples in unnecessary detail. In other instances, well-known devices, processes, systems, structures, and techniques may be shown without necessary detail so as to avoid obscuring the examples. The terms and expressions employed in this disclosure are used as terms of description rather than terms of limitation, and there is no intention in the use of such terms and expressions to exclude any equivalents of the features shown and described or portions thereof. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or designs.

[0039] FIG. 1 is a simplified diagram of an example of a positioning system 100, according to some embodiments. In the positioning system 100, the UE 105, the location server 160, and / or other components of the positioning system 100 can use techniques provided herein to determine an estimated location of the UE 105. The estimated location of the UE 105 can be used in a variety of applications, such as to assist direction finding or navigation for a user of the UE 105, or to assist another user (e.g., associated with an external client 180) in locating the UE 105. The location of the UE 105 may include an absolute location of the UE 105 (e.g., latitude and longitude and possibly an altitude) or a relative location of the UE 105, such as a location expressed as a distance north or south, east or west, and possibly above or below some other location, such as some other known fixed location or the location of the UE 105 at some known prior time. The location may also be specified as a geodetic location (as latitude and longitude) or as a civic location (e.g., by street address or using other location-related names and labels). The location may further include an indication of uncertainty or error, such as the horizontal and possibly vertical distance by which the location is expected to be in error, or an indication of an area or volume (e.g., a circle or ellipse) within which the UE 105 is expected to be located with a certain level of confidence (e.g., a 95% confidence level).

[0040] In this example, Figure 1 illustrates the UE 105 as a smartphone device. However, the UE may be any suitable device that includes GNSS capabilities, or may be a device or machine with such GNSS functionality built into it. For example, the UE 105 may include personal devices such as smartphones, smart watches, tablets, laptops, etc. However, the UE may also include larger types of devices, including vehicles with built-in GNSS receivers and positioning systems, such as boats, ships, cars, trucks, aircraft, drones, etc.

[0041] The positioning system 100 may include a UE 105, one or more GNSS satellites 110 (also referred to as space vehicles (SVs)) for a global navigation satellite system (GNSS), such as the Global Positioning System (GPS), a base station 120, an access point (AP) 130, a location server 160, a network 170, and an external client 180. In general, the positioning system 100 may estimate a location of the UE 105 based on RF signals received by and / or sent from the UE 105 and known locations of other components (e.g., the GNSS satellites 110, the base stations 120, or the APs 130) that transmit and / or receive the RF signals. Additional details regarding specific location estimation techniques are discussed in more detail below.

[0042] FIG. 1 provides a generalized view of the various components, and any or all of the components may be utilized as appropriate, and each of the components may be replicated as necessary. In particular, while only one UE 105 is shown, it will be understood that many UEs (e.g., hundreds, thousands, millions, etc.) may utilize the positioning system 100. Similarly, the positioning system 100 may include more or fewer base stations 120 and / or APs 130 than those shown in FIG. 1. The illustrated connections connecting the various components in the positioning system 100 include data and signaling connections, which may include additional (intermediate) components, direct or indirect physical and / or wireless connections, and / or additional networks. Furthermore, the components may be rearranged, combined, separated, substituted, and / or omitted depending on the desired functionality. In some embodiments, for example, the external client 180 may be directly connected to the location server 160. Those skilled in the art will recognize many modifications to the illustrated components.

[0043] Depending on the desired functionality, the network 170 may include any of a variety of wireless and / or wireline networks. The network 170 may include any combination of, for example, public and / or private networks, local area networks and / or wide area networks, etc. Additionally, the network 170 may utilize one or more wired and / or wireless communication technologies. In some embodiments, the network 170 may include, for example, a cellular or other mobile network, a wireless local area network (WLAN, e.g., WiFi), a wireless wide area network (WWAN, such as GSM, CDMA, LTE, 5G NE, or WiMAX), and / or the Internet. Examples of the network 170 include an LTE wireless network, a 5G NR wireless network, a Wi-Fi WLAN, and the Internet. LTE, 5G, and NR are wireless technologies defined or being defined by the 3rd Generation Partnership Project (3GPP). As used herein, the terms “5G NR,” “5G,” and “NR” are used interchangeably to refer to these wireless technologies. The network 170 may also include two or more networks and / or two or more types of networks.

[0044] The base stations 120 and the access points (APs) 130 are communicatively coupled to the network 170. In some embodiments, the base stations 120 may be owned, maintained, and / or operated by a cellular network provider and may employ any of a variety of wireless technologies, as described herein below. Depending on the technology of the network 170, the base stations 120 may include a Node B, an evolved Node B (eNode B or eNB), a base transceiver station (BTS), a radio base station (RBS), a NR Node B (gNB), a next generation eNB (ng-eNB), etc. The base stations 120 that are gNBs or ng-eNBs may be part of a next generation radio access network (NG-RAN), which may connect to a 5G core network (5G CN) if the network 170 is a 5G network. The APs 130 may include, for example, a Wi-Fi AP or a Bluetooth AP. Thus, the UE 105 may transmit and receive information to and from a network connectivity device, such as the location server 160, by accessing the network 170 via the base stations 120 using the first communication link 133. Additionally or alternatively, the AP 130 may also be communicatively coupled to the network 170 so that the UE 105 may use the second communications link 135 to communicate with Internet-connected devices including the location server 160 .

[0045] The location server 160 may include a server and / or another computing device configured to determine an estimated location of the UE 105 and / or provide data (e.g., “assistance data”) to the UE 105 to facilitate location determination. According to some embodiments, the location server 160 may include a Home Secure User Plane Location (SUPL) Location Platform (H-SLP), which may support a SUPL User Plane (UP) location solution defined by the Open Mobile Alliance (OMA) and may support location services for the UE 105 based on subscription information for the UE 105 stored in the location server 160. In some embodiments, the location server 160 may include a Discovery SLP (D-SLP) or an Emergency SLP (E-SLP). The location server 160 may alternatively include an Enhanced Serving Mobile Location Center (E-SMLC) that supports the location of the UE 105 using a Control Plane (CP) location solution for LTE radio access by the UE 105. The location server 160 may further include a location management function (LMF) that supports the location of the UE 105 using a control plane (CP) location solution for NR radio access by the UE 105. In a CP location solution, signaling for controlling and managing the location of the UE 105 may be exchanged between elements of the network 170 and the UE 105 as signaling from the perspective of the network 170 using existing network interfaces and protocols. In a UP location solution, signaling for controlling and managing the location of the UE 105 may be exchanged between the location server 160 and the UE 105 as data from the perspective of the network 170 (e.g., data transported using Internet Protocol (IP) and / or Transmission Control Protocol (TCP)).

[0046] As described above (and discussed in more detail below), the estimated location of the UE 105 may be based on measurements of RF signals sent from and / or received by the UE 105. In particular, these measurements may provide information regarding the relative distance and / or angle of the UE 105 from one or more components in the positioning system 100 (e.g., the GNSS satellites 110, the AP 130, and the base station 120). The location of the UE 105 may be estimated geometrically (e.g., using multi-angulation and / or multi-lateration techniques) based on the distance and / or angle measurements along with the known positions of the one or more components.

[0047] Terrestrial components such as AP 130 and base station 120 may be fixed, although embodiments are not so limited. In some embodiments, mobile components may be used. Additionally, in some embodiments, the location of UE 105 may be estimated based at least in part on measurements of RF signals communicated between UE 105 and one or more other UEs (not shown in FIG. 1), which may be mobile or fixed. Direct communication between UEs in this manner may include sidelink and / or similar device-to-device (D2D) communication techniques. Sidelink, as defined by 3GPP, is a form of D2D communication under cellular-based LTE and NR standards.

[0048] The external client 180 may be a web server or remote application that may have some association with the UE 105 (e.g., that may be accessed by a user of the UE 105), or may be a server, application, or computer system that provides location services to some other user that may include obtaining and providing the location of the UE 105 (e.g., to enable services such as finding friends or relatives, asset tracking, or location of children or pets). Additionally or alternatively, the external client 180 may obtain and provide the location of the UE 105 to an emergency service provider, a government agency, or the like.

[0049] A global navigation satellite system may include a constellation of SVs in synchronous orbits to transmit navigation signals, for example, from multiple SVs in the constellation simultaneously to locations over a vast portion of the Earth's surface. SVs that are members of a particular GNSS constellation typically transmit navigation signals in a format specific to that particular GNSS constellation. A GNSS receiver (e.g., in the UE 105) may be used to determine both absolute and relative locations of the UE 105. The GNSS receiver may include a receiver capable of receiving broadcast signals from GNSS satellites 110, such as, for example, satellites for the Global Positioning System (GPS, United States), Galileo (European Union), Glonass (Russia), Beidou (China), etc. The GNSS receiver may determine the absolute position and velocity of the UE 105 by processing the signals broadcast by the satellites. The GNSS satellites 110 may orbit at altitudes, for example, from about 20,000 km to about 23,000 km, and may have highly accurate known time and ephemeris. The GNSS satellites 110 may broadcast GNSS signals including a pseudo-random pattern. The GNSS signals may include carrier frequencies in the L-band, such as 1575.42 MHz (L1), 1227.6 MHz (L2), or 1176.45 MHz (L5), modulated at about 1 MHz and / or about 10 MHz. The GNSS receiver may receive GNSS signals broadcast by three or more GNSS satellites 110. Because the satellites are constantly moving, the GNSS receiver may continuously acquire and track signals from satellites in view and calculate its distance to the set of satellites based on the speed of electromagnetic waves (e.g., the speed of light) and the propagation time (e.g., the time of flight) of the incoming signal traveling through space, which may be determined using the satellite's and the receiver's local clocks.

[0050] FIG. 2 shows frequency bands for an example of a global navigation satellite system. FIG. 2 shows frequency bands for the Radio Navigation Satellite System (RNSS). There are two bands in the spectrum allocated primarily to the Aeronautical Radio Navigation Service (ARNS). These bands may be suitable for Safety-of-Life applications because other users are not allowed to interfere with these bands. These bands include the upper L band and the lower part of the lower L band. The upper L band includes GPS L1 signals, Galileo E1 signals, and GLONASS G1 signals. The lower part of the lower L band includes GPS L5 signals and Galileo E5 signals, with the E5 and L5 signals coexisting at the same frequency. The remaining GPS L2 signals, GLONASS G2 signals, and Galileo E6 signals are in the band between about 1,215.6 MHz and about 1,350 MHz. These bands are primarily allocated to radio location services (ground radar) and RNSS, and therefore GNSS signals in these bands may be more susceptible to interference. [Table 1]

[0051] In the GPS system, the GPS L1 signal may include a navigation message, a coarse acquisition (C / A) code that is unencrypted and freely available to the public, and an encrypted precision (P) code or P(Y) code (limited access) that is used exclusively by licensed U.S. military receivers. The navigation message may be a low bit rate (e.g., about 50 bps) message that includes, for example, GPS date and time, satellite status and health, satellite ephemeris data (which allows the receiver to calculate the satellite's position), and an almanac that includes information and status (e.g., coarse orbit and status information) about all GPS satellites so that the GPS receiver knows which satellites are available for tracking. GNSS signals may pass through the near vacuum of space and various layers of the atmosphere up to the Earth and be received by a GNSS receiver. In some embodiments, satellite assistance information may be downloaded from a server to determine the location of the GNSS receiver relative to the satellites based on the known location of each satellite, the location of the GNSS receiver (and therefore the UE 105) on Earth, in conjunction with the received signals.

[0052] A GNSS receiver may generally track three or more (e.g., four or more) satellites in the line of sight of the GNSS receiver's antenna and have a small dilution of precision (DOP) for receiving GNSS signals from the satellites. For each tracked satellite, the GNSS receiver may determine the time of propagation of a pseudorandom noise (PRN) code, for example, including 1023 bits or more. A GNSS receiver using code-based techniques may correlate or match the PRN code broadcast by the satellite to determine its time and position. The GNSS receiver may know the PRN code for each satellite and therefore may determine the time at which the GNSS receiver receives the code from a particular satellite to determine the time of propagation. The time of propagation may be multiplied by the speed of light in free space to determine the distance between the GNSS receiver and a particular satellite, which may be referred to as a "pseudorange" since the calculated distance may include errors (e.g., GNSS receiver clock errors and other errors) and therefore may not be strictly equal to the actual distance. Using positioning techniques such as trilateration techniques, satellite ephemeris data, and calculated distances between the GNSS receiver and each of the three or more satellites, the GNSS receiver can determine the location of the GNSS receiver as the intersection of the three or more spheres. Due to relatively large clock errors in the GNSS receiver, the three or more spheres may not intersect at a single point. The GNSS receiver can adjust the delay of its own clock to determine the time of flight and pseudorange until the three or more spheres intersect approximately at a single point that indicates the measured location of the GNSS receiver.

[0053] There may be many errors associated with GNSS-based positioning systems. For example, the atomic clocks in GNSS satellites are very accurate, but may still drift slightly, thus resulting in an error of, for example, about ±2 meters. As with the satellite clocks, the satellite orbits may also vary slightly, thus resulting in an error of, for example, about ±2.5 meters. To achieve better accuracy, GNSS receivers may need to compensate for satellite clock and orbit errors. For example, some GNSS receivers may use carrier-based techniques, such as the Real Time Kinematic (RTK) technique and the Precise Point Positioning (PPP) technique, which measure the phase of the carrier wave. Because the carrier wave of the GNSS signal is a sine wave with a period of less than 1 meter (e.g., about 19 cm for the L1 carrier signal), much more precise measurements of the flight time may be achieved using carrier-based techniques. In some positioning systems, the GNSS receiver may download correction data, for example from Satellite-Based Augmentation System (SBAS) or PPP service satellites, or from differential GNSS or RTK base stations, to further improve the accuracy of the positioning.

[0054] For example, in an SBAS system, reference stations geographically distributed throughout the SBAS service area may receive GNSS signals and forward the GNSS signals to a master station. Because the locations of the reference stations are precisely known, the master station may accurately calculate wide-area correction data. The calculated correction data may be uploaded to SBAS satellites, which may broadcast the correction data to GNSS receivers within the SBAS coverage area. PPP techniques may also use correction data broadcast from the satellites. In addition, PPP techniques may use carrier-based ranging to achieve better accuracy.

[0055] In a differential GNSS system, the position of a fixed GNSS receiver (called a base station) may be determined with high accuracy, and the base station may compare the known high-accuracy position with a position calculated using GNSS signals. The difference between the two positions may be due to errors associated with satellite ephemeris and clock errors, as well as atmospheric delays. The base station may send these calculated errors to other GNSS receivers (e.g., rovers, or vehicle-mounted GNSS receivers), which may then use the calculated errors to make corrections to their position calculations. RTK techniques can also remove errors common to the base station and the rover. In addition, RTK techniques may use carrier-based ranging to achieve better accuracy.

[0056] GNSS signals can only propagate in a straight line in a vacuum or through a completely homogeneous medium, and may bend as they pass through the Earth's atmosphere. The layer of the Earth's atmosphere that most affects the transmission of GPS (and other GNSS) signals is the ionosphere, a layer that is located about 70 km to about 1,000 km above the Earth's surface and contains ionized gas molecules and free electrons created by, for example, ultraviolet light from the Sun. The ionosphere may delay satellite signals and may result in a significant amount of satellite position error, such as ±5 meters. Ionosphere delays may vary with solar activity, time of year, season, time of day, location, etc., and therefore may be difficult to predict. Ionosphere delays may also be frequency dependent and therefore may be determined and removed by calculating distances using both L1 and L5 (or L2) signals. Ionosphere conditions may be similar within a local area, and as a result, base station and rover receivers may experience similar ionosphere delays. Thus, ionospheric delays can be compensated for using, for example, differential GNSS or RTK systems.

[0057] Another layer of the Earth's atmosphere that may affect the transmission of GNSS signals is the troposphere layer, the lowest layer of the Earth's atmosphere. The delay caused by the troposphere layer may depend on the local temperature, pressure, relative humidity, etc. L1 and L2 signals may be equally delayed by the troposphere, and therefore the effects of tropospheric delay may not be eliminated using GNSS signals in multiple frequency bands. The troposphere may be modeled to predict and compensate for most of the tropospheric delay. Because tropospheric conditions are generally similar within a local area, base station and nearby rover receivers may experience similar tropospheric delay, which may be compensated for in differential GNSS or RTK systems.

[0058] Some of the GNSS signals transmitted by the satellites may be reflected by structures and other objects on the way to the GNSS receiver. This phenomenon is called multipath propagation. The reflected signals may travel a longer distance and therefore be delayed from the direct signal and may interfere with the direct signal if the reflected signals are strong enough. The delayed signals may cause the receiver to calculate an inaccurate position. Multipath errors can be difficult to handle since they are generally local errors that the base station may not be subject to as well. Techniques have been developed that allow the receiver to consider only the earliest arriving (or strongest) signals and ignore later arriving multipath signals. In some cases, expensive high-end GNSS receivers and antennas may be required to reduce long-delay and short-delay multipath errors.

[0059] As explained above, GNSS satellites transmit signals in multiple frequency bands. A GNSS receiver may simultaneously tune to one or more bands to improve the accuracy of the retrieved position, such as by canceling non-constant ionospheric delays that depend on the frequency of the signal. Electromagnetic waves transmitted by the satellites reach the antenna of the GNSS receiver after traveling approximately 20,000 km or more. Signals transmitted by GNSS SVs generally have very low signal strength (e.g., less than approximately -120 dBm) when they reach the GNSS receiver. The electromagnetic waves are converted to electrical signals and demodulated to determine raw data such as pseudorange, phase, carrier-to-noise ratio (C / N0), and Doppler shift. Pseudorange is the apparent distance between each satellite and the receiver. Phase is a precise (but ambiguous) measurement of the electromagnetic waves. C / N0 is related to the received power. Doppler shift is a measurement of the relative motion between the receiver and the satellite. This information may be provided to a navigation engine, which can solve a set of equations to derive information about the latitude, longitude, height, and time of the GNSS receiver.

[0060] 3 is a simplified block diagram of an example of a GNSS receiver 300. The GNSS receiver 300 is a spread spectrum receiver for acquiring, tracking, and extracting useful information from incoming satellite signals. The GNSS receiver 300 may include an antenna 310, a radio frequency (RF) front end 320, an intermediate frequency (IF) / baseband (BB) signal processing section 330, and a navigation engine 340. The RF front end 320 and the IF / BB signal processing section 330 may each include various hardware modules, while the navigation engine 340 may be implemented using software.

[0061] The antenna 310 may be configured to receive right-hand circularly polarized (RHCP) signals transmitted by GNSS satellites. The antenna 310 may need to be able to receive GNSS signals in different frequency bands, polarizations, and elevation angles. The antenna gain pattern of the antenna 310 may indicate how well the antenna 310 works at various center frequencies, polarizations, and elevation angles. Further details of the antenna 310 are described below.

[0062] In the illustrated example, the RF front end 320 may include an optional pre-filter 322, a pre-amplifier 324, a down-converter 326, and a local oscillator 328. The pre-filter 322 may filter the received signal from the antenna 310 to remove signals outside the L-band, reduce the effects of aliasing, and limit the noise bandwidth. Wide bandwidth signals can provide high resolution measurements in the time domain, but may require a higher sampling rate, causing the receiver to consume much more power. The filter can mitigate this by allowing narrower band signals to pass. In some embodiments, the pre-filter 322 may be part of the pre-amplifier 324.

[0063] Since the antenna 310 may receive signals in multiple frequency bands, there may be one preamplifier per band, or a single broadband preamplifier for multiple bands. The preamplifier 324 may generally include a preselector filter (e.g., prefilter 322) that removes out-of-band interference and limits the noise bandwidth. The preamplifier 324 may also include a low noise amplifier (LNA) and burnout protection circuitry to prevent possible high power interference. GPS satellites have an orbital altitude of about 20,000 km (90 degrees elevation angle) from the Earth. The transmit power of each satellite may be about 45 watts at about 1575 MHz, and the antenna gain may be about 12 dB. If the antenna 310 has an antenna gain of 4 dB, the received signal power is less than about -120 dBm (about -125 dBm with additional losses such as atmospheric losses and antenna losses), while the noise power in the system bandwidth (e.g., about 2.0 MHz) may be about -110 dBm. Due to the direct spread spectrum modulation scheme, there may be a processing gain of 43 dB, so theoretically, the GNSS signal can be restored as long as it is greater than -153 dBm. However, to improve the quality of service, the received power strength may need to be higher than the theoretical level. For example, during acquisition, the received signal power may need to be -135 dBm or higher. During tracking, the received signal power may need to be -147 dBm or higher. The LNA generally needs to amplify the signal by about 20 dB to about 35 dB to increase the signal to a level suitable for processing.

[0064] The downconverter 326 may either convert the RF frequency signal to an intermediate frequency signal or directly to a baseband signal to facilitate the sampling and filtering processes. Downconversion is typically performed using a mixer. The mixer may multiply the received signal with a carrier signal generated locally by the local oscillator 328 and then filter the output signal to remove higher order signals and maintain the differential (e.g., heterodyne) signal. Filtering and downconversion may be accomplished in multiple successive stages. The GNSS receiver makes measurements by estimating the time of arrival, carrier phase, and frequency of the received signal. In some embodiments, a single local reference oscillator may be used to synthesize all reference signals used in the receiver, for example, using a combination of integer and fractional frequency multiplication. In some cases, the GNSS receiver may have multiple frequency references for downconversion.

[0065] The IF / BB signal processing section 330 may include, for example, an analog-to-digital converter 332, an acquisition module 334, and one or more tracking units 336. The ADC 332 may digitize the IF or baseband analog signal to a digital signal at baseband. In some embodiments, an automatic gain control (AGC) stage 338 may be used to adjust the gain of the RF front end 320.

[0066] As explained above, during the signal acquisition process, a GNSS receiver can identify satellites visible to the receiver and provide measurements of the Doppler shift in carrier frequency and delay in the C / A code of the incoming GNSS signal. The Doppler shift in the carrier frequency of the GNSS signal can be caused by the relative velocity of the satellite with respect to the receiver. Satellites in a GNSS system move in high-speed orbits around the Earth, and the orbits can vary for different constellations (e.g., low Earth orbit, medium Earth orbit, coverage, etc.). Thus, although a satellite may transmit at a starting frequency f0, there is a Doppler shift associated with the satellite signal received at the GNSS receiver. This shift is mostly due to the satellite motion (Δf sat ) and receiver movement (Δf receiver ) can also be caused by the GNSS receiver. sat +Δf receiver The satellite signals may be detected at the baseband. The C / A code delay is due to the transit time of the satellite signal from the satellite to the GNSS receiver. Within a given satellite band, e.g., L1 for GPS, each satellite typically transmits at the same frequency but uses orthogonal coding, so that different satellite signals may be detected and their respective pseudoranges may be determined in baseband. In contrast, GLONASS satellites share the same coding but use different sub-bands for the satellite signals.

[0067] As also explained above, each satellite in the GPS system may transmit a PRN code that includes, for example, 1023 bits or more. The PRN code may be unique to each satellite. For each tracked satellite, the GNSS receiver may determine the propagation time of the PRN code. The GNSS receiver may know the PRN code for each satellite at a given time and may generate an electronic replica using the GNSS receiver's own clock. The GNSS receiver may then compare the replica signal with the received GNSS signal. Since the GNSS signal was actually created at the satellite some time ago (e.g., about 0.07 seconds ago) due to the finite speed of electromagnetic waves, the replica signal at the receiver needs to be delayed in order to match or align the incoming signal with the replica signal. This time delay includes the time for the signal to propagate from the satellite to the receiver and errors in the satellite clock and the receiver clock.

[0068] In some embodiments, the time delay may be determined by autocorrelation. In autocorrelation, the first bit from the incoming signal is multiplied by the first bit of the replica signal. For example, if the first bits from the two signals both have a value of -1, the result is (-1) x (-1) = +1. Similarly, if both bits have a value of +1, the result is +1. On the other hand, if the two bits do not match, the result is (+1) x (-1) = -1. This process is repeated for the second pair of bits, and so on. The result may be written as a sequence of +1 (if the bits match) and -1 (if the bits do not match). This sequence is then summed and divided by the total number of bits in each signal. For example, if signal A contains (+1, -1, -1, +1, -1) and signal B contains (+1, +1, -1, -1, +1), multiplying them gives (+1, -1, +1, -1, -1), which sums to -1, and dividing the sum by the number of bits (5) gives -0.2. If the two signals match perfectly, the result will be +1. When the two signals contain pseudorandom patterns and do not match exactly in time, the result of the autocorrelation can be close to 0. When the two signals are aligned in time, the result will be close to +1 (although not exactly, since real signals also have noise and therefore some bits are inaccurate). In general, the more bits compared, the better the resolution. The autocorrelation function may have the shape of an equilateral triangle with a value of 1 at its apex (in the absence of noise), which may be used to find the time displacement that maximizes the autocorrelation.

[0069] To lock on to a GNSS satellite signal, the GNSS receiver may perform a two-dimensional search of the signal, for example using the autocorrelation technique described above. The first dimension is the signal frequency. The receiver needs to determine the carrier frequency including the Doppler shift. Once the carrier frequency and Doppler shift have been estimated, this is tracked, for example with a phase-locked loop (PLL). The second dimension is time. As explained above, the GPS signal for each satellite includes a 1023-bit long PRN code sent at a rate of 1.023 Mbits per second, so that the code repeats every millisecond. To acquire in the time dimension, the receiver may set its internal clock to align with the correct time slot of the 1023 possible time slots by searching among the possible values. Once the correct delay is found, this is tracked, for example with a delay-locked loop (DLL).

[0070] Acquisition may be performed on a block of data received from a satellite signal, such as during the duration of a C / A code (e.g., 1 ms). The acquisition module 334 may synchronize the locally generated carrier and C / A code with the received signal, as described above. The acquisition module 334 may estimate the Doppler frequency and code delay of the signal from each satellite. In one example, the GNSS signal from the RF front end is multiplied with a locally generated reference signal. The resulting carrier-free signal (e.g., a baseband signal) is multiplied with a locally generated PRN code with a fixed delay. The result is then integrated as described above for a fixed period of time depending on the type of signal and the signal-to-noise ratio. The integration result may be compared to a threshold to determine whether the signal has been found. If the integration result is greater than the threshold, the frequency and / or code delay of the locally generated reference signal may be handed over to the tracking unit 336 for further processing. If the integration result is less than the threshold, the frequency of the locally generated reference signal and / or the delay of the locally generated PRN code may be adjusted to continue searching for (acquiring) a suitable satellite until they match the frequency and code delay of the received signal, thereby producing an integration result greater than the threshold.

[0071] After identifying available satellites and acquiring parameters such as frequency and code delay of the received signal from each of the three or more satellites, a parallel channel (e.g., tracking unit 336) may be used to track the frequency and delay of the identified satellites, for example, using the PLL and DLL described above.

[0072] The output from the IF / BB signal processing section 330 may be raw data, such as the pseudorange to each satellite, the code delay and Doppler frequency of the incoming signal from each satellite, the phase delay, and the carrier-to-noise ratio (C / N0) or signal-to-noise ratio (SNR). The navigation engine 340 may use the raw data generated by the IF / BB signal processing section 330 for three or more satellites to determine a user's position (e.g., x, y, and z coordinates), velocity, and time information, or loss of signal lock.

[0073] As explained above, a GNSS receiver may need to use one or more antennas to receive GNSS signals in different L-bands. A portable device including a GNSS receiver may also include antennas for other purposes, such as cellular communication services, high-speed data services, etc. Antennas are a key component for any connected device, such as a mobile phone or an Internet of Things (IoT) device. Designing a suitable antenna that can both achieve the desired performance and have a small footprint to fit snugly into a compact portable device, such as a smartphone, smartwatch, or IOT device, remains a challenging task.

[0074] FIG. 4A shows an example of radio frequency antennas in an example of a smartphone 400. A smartphone can have multiple antennas, such as four to thirteen or more different antennas. The antennas can include different types of antennas, such as cellular antennas, Wi-Fi antennas, Bluetooth antennas, and GPS antennas. Some smartphones can also include ZigBee (IEEE 802.15.4 at 930 MHz and below) antennas, FM radio antennas, and magnetic near field communication (NFC) antennas. Each type of antenna can include one or more antennas. For example, there may be two to four antennas for cellular communication and one or more antennas for Wi-Fi and WiMAX. Multiple antennas can allow the smartphone to avoid dropouts, for example, when a user's hand blocks one antenna during a conversation. Having multiple antennas for the same communication link can also allow smartphone carriers to combine multiple streams to improve data transfer rates. In some embodiments, an antenna can be used for both transmitting and receiving signals. In some embodiments, an antenna may be dedicated to receiving signals (called a diversity antenna), such as receiving GNSS signals or receiving high-speed data signals. Some antennas may be dual-band or multi-band antennas.

[0075] In the illustrated example, the smartphone 400 may include two WiMAX antennas (e.g., operating at 2.6 GHz), one for both Tx / Rx and one as a diversity (Rx only) antenna. The WiFi antenna may operate at a different frequency band than the frequency band for the cellular antenna. For example, the WiFi antenna may operate at 2.4 GHz or 5.8 GHz, while the cellular antenna may operate at 800 MHz, 900 MHz, 1800 MHz, 1900 MHz, 2100 MHz, 2.3 GHz, 2.5 GHz, sub-6 GHz, about 5.9 GHz to 7.2 GHz, millimeter wave frequencies (e.g., around 28 GHz or 37 GHz), etc. An antenna can only pick up electromagnetic signals well at frequencies at which the antenna naturally resonates. In general, the resonant frequency of an antenna depends on its physical size, but the frequency may be modified without changing the size by adding some electronic components to tune the antenna.

[0076] There may be some physical limitations related to how close these antennas can be to each other and what shape they can be. Most antennas may be mounted on a PCB that may be located around the edges of the smartphone 400 and may also include many other components mounted thereon (not shown in FIG. 4A), such as a processor, memory, transceiver, modem, audio codec, image processing circuitry, display driver, power management circuitry, etc. Thus, the form factor of the antenna may need to be small to fit into the device without affecting the performance of other components and the device. For example, a GNSS antenna may need to be 10 cm in size to fit into a smartphone. 2It may be necessary to be less than 1000 MHz. Some popular printed antennas for smartphones and portable devices include patch antennas, inverted-F antennas (IFAs), or planar inverted-F antennas (PIFAs), and a large ground plane in the PCB may be used as the ground plane for all antennas. If the size of the ground plane is reduced (e.g., cut in some areas), the smartphone may not radiate well in some frequency bands, such as lower frequencies with longer wavelengths.

[0077] FIG. 4B illustrates an example of a radio frequency antenna including a PIFA 405. The PIFA 405 may look like the letter "F" in side view. The PIFA 405 includes two shorter sections that provide a feed (e.g., section 454) and a short to ground (e.g., section 456), a tail 450 (or top patch) as a radiating surface, and a ground plane 452. The PIFA 405 may resonate at a quarter wavelength (thus reducing the physical dimensions of the PIFA 405) due to the short pins (e.g., section 456) at the ends. The feed pins (e.g., section 454) are located between the open and short ends, and the location of the feed pins may control the input impedance. The PIFA 405 may generally have good Specific Absorption Rate (SAR) characteristics, a low profile, and an omnidirectional pattern, and may be fabricated to radiate in more than one frequency band. Thus, PIFAs are increasingly used in smartphones, even though they are generally linearly polarized and their efficiency may be moderate.

[0078] As explained above, GNSS signals are typically generated with circular polarization. Circularly polarized electromagnetic waves may contain two orthogonal linearly polarized components that are out of phase by approximately 90°. The two orthogonal linearly polarized components of a circularly polarized GNSS signal may undergo the same level of Faraday rotation at high elevation angles as they pass through the ionosphere. Thus, the polarization purity of the signal may not be reduced. For linearly polarized signals, Faraday rotation may rotate the signal to a polarization angle different from the original polarization angle, which may need to be compensated for at the receiving antenna on Earth, either by rotating the antenna for polarization compensation or by utilizing both orthogonal components of the received signal. In addition, circular polarization may be more tolerant to physical orientation mismatches. For example, if an antenna transmits a signal with vertical polarization, a vertically oriented linear antenna may receive a strong signal, but if the antenna is rotated by 90°, the received signal strength may be reduced by 20 dB or more. However, if the antenna transmits a circularly polarized signal, the linear antenna may receive the signal with less loss (eg, about 3 dB) regardless of whether the linear antenna is oriented vertically or horizontally.

[0079] FIG. 5A illustrates the rotation of the electric field vector of an example of a circularly polarized electric signal 510. The circularly polarized electric signal 510 may include a first component 512 having an electric field oscillating in a vertical plane (e.g., YZ plane) and a second component 514 having an electric field oscillating in a horizontal plane (e.g., XZ plane). Thus, the first component 512 and the second component 514 are both linearly polarized and synchronous, but orthogonal to each other. Depending on the phase and / or amplitude difference between the first component 512 and the second component 514, the composite wave may be linearly polarized, circularly polarized, or elliptically polarized. For example, when the phases of the first component 512 and the second component 514 are the same, the composite wave may be linearly polarized and the electric field vectors point in the same direction.

[0080] In a circularly polarized signal, the electric field vectors do not point in the same direction. Instead, the electric field vector rotates 360° per wavelength during wave propagation. The rotation is achieved by the specific excitation of the orthogonal components. Circular polarization can occur when the phase delay between the two orthogonal components is approximately 90°. When the phase delay between the two orthogonal components is not 90°, the composite signal may not be circularly polarized, but may be elliptically polarized. Depending on whether the horizontal or vertical component comes first, the sense of circular rotation may be different, which can determine whether the polarization is right-handed or left-handed circularly polarized. The purity of circular polarization is described in terms of the axial ratio, which is defined as the ratio of the two orthogonal components of the electric field on the polarization ellipse that the electric field vector follows in the time domain. The axial ratio varies with elevation and azimuth angles, but is usually stated as a single value at the zenith angle.

[0081] FIG 5B shows examples of signals with left-handed or right-handed circular polarization. Chart 550 shows a right-handed circularly polarized signal, where the signal's direction of propagation is in the +z direction and the electric field vector rotates clockwise when viewed from the direction of propagation. The circularly polarized electrical signal 510 shown in FIG 5A is an example of an RHCP signal. Chart 552 shows a left-handed circularly polarized signal, where the signal's direction of propagation is in the +z direction and the electric field vector rotates counterclockwise when viewed from the direction of propagation.

[0082] As explained above, RHCP GNSS signals are traditionally chosen for signal transmission. Thus, the upward-looking antenna is generally an RHCP antenna to capture direct (line-of-sight) signals. When the GNSS signal is specularly reflected at low incidence angles, the polarization of the signal is reversed after reflection, and thus becomes LHCP. Thus, for GNSS-R measurements, the downward-looking antenna is generally an LHCP antenna. In the case of partially reflecting surfaces or high incidence angles, the relative contribution of the two linearly polarized components in the reflected signal may change. A good GNSS antenna may have an axial ratio of less than 1 dB at the zenith angle.

[0083] Linearly polarized antennas are prevalent in smartphones because they are relatively easy to fit into smartphones and can accept both RHCP, LHCP, or linearly polarized signals. However, because transmitted GNSS signals are generally circularly polarized, there can be as much as a 3 dB loss in the signal level received by a linearly polarized antenna. In addition, in a multipath environment, with each reflection, the polarization changes from RHCP to LHCP and back to RHCP. Because linearly polarized antennas can receive both RHCP, LHCP, or linearly polarized signals, linearly polarized antennas may not be able to distinguish between line-of-sight and reflected signals, which can cause positioning errors.

[0084] Designing a circularly polarized antenna for use in a smartphone can be difficult due to physical size and PCB area limitations, PCB shape constraints (e.g., caused by industrial design, battery size, etc.), and limited freedom in antenna placement. The wavelength of the GPS carrier is about 19 cm (for L1), about 24 cm (for L2), and about 25 cm (for L5). Antennas that are 1 / 4 or 1 / 2 wavelength are generally the most practical and efficient. Thus, the GPS antenna element can be as small as 4 cm or 5 cm or less. For example, in some embodiments, a material with a higher dielectric constant (e.g., ceramic instead of FR-4) can be used as the PCB material for the antenna so that the wavelength of the GPS carrier, and therefore the antenna size, can be reduced.

[0085] As explained above, most smartphones have PCBs that are multi-layer stacks with multiple layers of metal planes (e.g., copper). The integrated circuits (ICs) placed on the PCB and the interconnect traces routed on the PCB may use some copper cutouts. The ground plane may need to be excited in a specific way to perform circular polarization. Therefore, it may be very difficult to modify the ground plane in a desired way and excite currents on the ground plane to perform circular polarization with an axial ratio close to 0 dB without affecting the performance of other circuits. For example, even though an RHCP antenna may be implemented using a patch antenna, the area used for the patch antenna and the ground clearance on the PCB for the patch antenna may not be practical in a smartphone design. In addition, the shape of the PCB and its associated ground plane may be dictated by the industrial design and battery size of the smartphone and therefore may not be optimized to perform circular polarization. Furthermore, because the ground plane needs to be excited in a specific way to perform circular polarization, the antenna may need to be placed in a specific location. However, since smartphones support multiple technologies other than GNSS, such as GSM / WCDMA, LTE, 5G NR, WiFi, WiMAX, Bluetooth, NFC, Zigbee, etc., which also require antennas for transmit and receive diversity, GNSS antennas may not be placed in any desired location.

[0086] As explained above, a circularly polarized signal may include two orthogonal linearly polarized components, and a circularly polarized antenna may be constructed by combining the output from a horizontally polarized antenna with a 90° phase shift between these two outputs. The relative phase of these two outputs may determine whether the combined antenna functions as an RHCP antenna, an LHCP antenna, or an elliptically polarized antenna. For example, the circularly polarized electrical signal 510 shown in FIG. 5A may have an RHCP, where the phase of the vertical component (e.g., first component 512) may be 90° ahead of the phase of the horizontal component (e.g., second component 514), such that the resulting electric field vector may rotate clockwise when viewed from the propagation direction (e.g., Z direction). When the phase delay between the horizontal and vertical components is not 90° and / or the amplitude of the horizontal component is not equal to the amplitude of the vertical component, the combined RF signal may be elliptically polarized.

[0087] According to some embodiments, a GNSS antenna in a smartphone or another portable device (e.g., a smartwatch) may include two or more linearly polarized antennas (e.g., PIFAs) and a 90° hybrid coupler coupled to the two or more linearly polarized antennas. The 90° hybrid coupler may combine linearly polarized signals received by two linearly polarized antennas that may already be used in the smartphone for other purposes (e.g., WWAN, WLAN, or WPAN such as Bluetooth or ZigBee) to replicate an RHCP GNSS antenna with improved signal power and multipath rejection (e.g., by about 3 dB). The combined higher signal power with a reduced number of multipath signals may result in improved positioning accuracy. In some embodiments, the GNSS antenna, the WWAN antenna, the WLAN antenna, and / or the WPAN antenna may be tuned or switched to optimize antenna usage.

[0088] 6A illustrates an example of a circularly polarized GNSS receiver 600 according to some embodiments. In the illustrated example, the circularly polarized GNSS receiver 600 may include a first linearly polarized antenna 610, a second linearly polarized antenna 620, a 90° hybrid coupler 630, and optionally an RF front end 640 or a portion of the RF front end 640. The first linearly polarized antenna 610 and the second linearly polarized antenna 620 may have orthogonal polarizations. For example, the first linearly polarized antenna 610 may be a vertical linearly polarized antenna, while the second linearly polarized antenna 620 may be a horizontal linearly polarized antenna. The first linearly polarized antenna 610 and the second linearly polarized antenna 620 may be PIFAs that may be dedicated to GNSS, as described above and below, or may be antennas that may be used for other wireless technologies, such as WWAN, WLAN, WPAN, etc. In the example shown in FIG. 6A, the first linearly polarized antenna 610 and the second linearly polarized antenna 620 may be dedicated antennas for GNSS and may cover the GNSS L1, L2, and L5 frequency bands.

[0089] The 90° hybrid coupler 630 may be a passive device that has four ports and may be used as a splitter or combiner. When used as a splitter, an input signal at the "Input" port may be split equally in power (-3 dB each) to two output ports called the "Coupled" and "Output" ports. The phase of the output signal at the "Output" port is approximately 90° out of phase with the output signal at the "Coupled" port. No signal is coupled to the "Isolated" port, which may be terminated at 50 Ω by resistor 632. The 90° hybrid coupler 630 is symmetrical, so the "Input" and "Isolated" ports may be reversed and the phase of the output signal at the "Coupled" port may be 90° out of phase with the output signal at the "Output" port. The 90° hybrid coupler 630 may also be used in the reverse path as a combiner to combine input signals from the “combined” and “output” ports, where the output at the “input” port may be approximately 3 dB higher than each input signal. Due to different delays in the paths from the “combined” port to the “input” port and from the “output” port to the “input” port, synchronized linearly polarized inputs at the “combined” and “output” ports may be combined into an RHCP signal at the “input” port (or an LHCP signal at the “split” port).

[0090] In the illustrated example, a first linearly polarized antenna 610 (e.g., a vertical linearly polarized PIFA) may be coupled to the "combining" port, while a second linearly polarized antenna 620 (e.g., a horizontal linearly polarized PIFA) may be coupled to the "output" port. Thus, at the "input" port, the combined signal may be 3 dB stronger compared to the signals at the "output" and "combining" ports, and may be right-handed circularly polarized since the vertically polarized component may be 90° ahead of the horizontally polarized component. The 90° hybrid coupler 630 may be referred to as a quadrature coupler, and may include, for example, a Lange coupler, a branch-line coupler, an overlay coupler, an edge coupler, or a short-slot hybrid coupler. As explained above, the actual phase shift or phase delay of the 90° hybrid coupler may be, for example, between about 90°±45°, between about 90°±30°, between about 90°±15°, between about 90°±10°, between about 90°±5°, or between about 90°±2°. In general, the performance of the circularly polarized GNSS receiver 600 may be better when the phase delay is closer to 90° and may degrade when the phase delay deviates from 90°.

[0091] 6B shows an example of a 90° hybrid coupler 650 implemented using a branch-line coupler. The 90° hybrid coupler 650 may be an example of the 90° hybrid coupler 630. The 90° hybrid coupler 650 may include four ports. When the 90° hybrid coupler 650 is used as a splitter, port 1 is the input port, port 2 is the 0° output port, port 3 is the 90° output port, and port 4 is the isolation port. In the illustrated example, the 90° hybrid coupler 650 is used as a combiner, where the input signals are at ports 2 and 3 and are represented by vector A and vector B, respectively. Thus, the output at port 1 is vector

number

[0092] The branch-line coupler shown in FIG. 6B can be relatively easy to design and fabricate. The branch-line coupler has two main transmission lines (horizontal in FIG. 6B) shunt-connected by two branch lines (vertical in FIG. 6B). The impedances and dimensions of the transmission lines and branch lines are shown in FIG. 6B. The branch-line coupler is designed to be symmetrical as shown in FIG. 6B. Therefore, either port can be used as an input port or an output port to achieve the same behavior.

[0093] The 90° hybrid coupler can be very small. In one example, the 90° hybrid coupler can have a footprint of about 0.08×0.05 square inches with a height of about 0.7 mm, which can be small enough to be designed into a smartphone PCB. The 90° hybrid coupler can have a frequency range that covers all GNSS constellations and can have low insertion loss (e.g., <0.8 dB). The 90° hybrid coupler can also function as a filter to provide out-of-band rejection of frequencies, e.g., above 2.7 GHz, thus eliminating the need for additional filters in the front end.

[0094] FIG. 7 illustrates another example of a circularly polarized GNSS receiver 700 according to some embodiments. As with the circularly polarized GNSS receiver 600, the circularly polarized GNSS receiver 700 may include a first linearly polarized antenna 710, a second linearly polarized antenna 720, a 90° hybrid coupler 730, and optionally an RF front end 740 or a portion of the RF front end 740. The first linearly polarized antenna 710 and the second linearly polarized antenna 720 may have orthogonal polarizations. For example, the first linearly polarized antenna 710 may be a vertical linearly polarized antenna, while the second linearly polarized antenna 720 may be a horizontal linearly polarized antenna. The first linearly polarized antenna 710 and the second linearly polarized antenna 720 may be PIFAs that may be dedicated to GNSS, as described above, or may be antennas that may also be used for other wireless technologies, such as WWAN, WLAN, WPAN, etc. 7, the first linearly polarized antenna 710 and the second linearly polarized antenna 720 may be dedicated antennas for GNSS and may cover the GNSS L1, L5, and / or L2 frequency bands. The 90° hybrid coupler 730 may be similar to the 90° hybrid coupler 630 and may have two (input) ports connected to the first linearly polarized antenna 710 and the second linearly polarized antenna 720, one (output) port, and one (isolated) port terminated by a resistor 732.

[0095] The circularly polarized GNSS receiver 700 may also include a diplexer 750 capable of separating GNSS signals in different bands. In the illustrated example, the diplexer 750 may include a splitter that splits the signal from the output port of the 90° hybrid coupler 730 into two signals, and two filters that receive and filter the two signals. For example, the filter 752 may allow the GNSS L1 signal to pass, while the filter 754 may allow the GNSS L5 signal to pass. The separated GNSS L1 and GNSS L5 signals may then be processed by the RF front end 740, the IF / BB signal processing section, and the navigation engine, e.g., as described above with respect to FIG. 3.

[0096] As described above, a smartphone may need to support multiple wireless communication technologies and frequency bands covering a wide frequency range. Therefore, it may be difficult to dedicate two PIFA antennas to GNSS for circular polarization. According to some embodiments, at least one of the two antennas used to implement a circularly polarized antenna for GNSS may be shared with other wireless communication technologies (e.g., WWAN or WLAN) via an antenna tuner, such as an aperture tuner or an impedance tuner. The antenna may be tuned to the GNSS band when a circularly polarized antenna for GNSS is desired. If not, the antenna may be detuned from the GNSS band and used as a linearly polarized antenna for another wireless communication technology. Thus, the two antennas may be dynamically configured and / or tuned to replicate a circularly polarized antenna for receiving RHCP GNSS signals or to maintain linear polarization for receiving GNSS signals or signals for other wireless communication technologies, thus allowing a user to select an operating mode based on the environment and desired accuracy. As a result, a GNSS receiver may be able to determine a position fix with excellent accuracy in many conditions using one linearly polarized antenna, and may be able to obtain a more accurate position fix in some environments by duplicating a circularly polarized antenna. For example, when the smartphone is in a situation where improved accuracy can be achieved, such as in an open sky environment, the two antennas may be dynamically combined for GNSS purposes to achieve an additional 3 dB gain. In this way, both linearly and circularly polarized antennas may be implemented without increasing the total number of antennas in the smartphone.

[0097] 8 shows an example of a polarization configurable GNSS receiver 800 according to some embodiments. As in the case of the circularly polarized GNSS receiver 600 or 700, the polarization configurable GNSS receiver 800 may include a first linearly polarized antenna 810, a second linearly polarized antenna 820, a 90° hybrid coupler 830, an RF front end 840 or a portion of an RF front end 840, and a diplexer 850. The first linearly polarized antenna 810 and the second linearly polarized antenna 820 may have orthogonal polarizations. For example, the first linearly polarized antenna 810 may be a vertical linearly polarized antenna, while the second linearly polarized antenna 820 may be a horizontal linearly polarized antenna. The first linearly polarized antenna 810 and the second linearly polarized antenna 820 may be PIFAs that may be dedicated to GNSS, as explained above, or may be antennas that were used for other wireless communication technologies (or RATs), such as cellular, WiFi, WiMAX, etc. The 90° hybrid coupler 830 may be similar to the 90° hybrid couplers 630 or 730 and may have two (input) ports connected to the first linearly polarized antenna 810 and the second linearly polarized antenna 820, one (output) port, and one (isolation) port terminated by a resistor 832. The diplexer 850 may be similar to the diplexer 750 and may be used to separate GNSS signals in different bands, such as the GNSS L1 band and the GNSS L5 band.

[0098] In the example shown in FIG. 8, the first linearly polarized antenna 810 may be configured to receive GNSS signals and WWAN (e.g., GSM, CDMA, LTE, 5G NR, or WiMAX) signals. An extractor 860 (or another n-plexer, such as a diplexer) may be used to separate the GNSS and WWAN signals. The GNSS signal from the extractor 860 may be sent to a port (0° output port) of the 90° hybrid coupler 830. The resonant frequency (having a certain bandwidth) of the second linearly polarized antenna 820 may be tuned to the GNSS band and / or the WWAN band by a tuner 870, such as an aperture tuner or an impedance tuner. The signal received by the second linearly polarized antenna 820 may be selected by an n-plexer (e.g., a diplexer 880 or an extractor) to separate the GNSS and WWAN signals, or may be connected by a switch to either a port (90° output port) of the 90° hybrid coupler 830 or a WWAN receiver. The extractor 860, tuner 870, and diplexer 880 may be designed so that the loss from the first linearly polarized antenna 810 to the 90° hybrid coupler 830 and the loss from the second linearly polarized antenna 820 to the 90° hybrid coupler 830 can be approximately the same and as low as possible.

[0099] To receive RHCP GNSS signals, both the first linearly polarized antenna 810 (tuned for GNSS) and the second linearly polarized antenna 820 may be used, and the GNSS signals from the extractor 860 and the diplexer 880 may be sent to the 90° hybrid coupler 830. If the user may not need a circularly polarized antenna depending on the use case, the user may tune the second linearly polarized antenna 820 to a band other than the GNSS band by tuning the tuner 870. For example, the second linearly polarized antenna 820 may be tuned to the WWAN band to improve the performance of an existing WWAN support band or to create a new resonant frequency range to support WWAN diversity. The received signal in the WWAN band may be separated (disconnected) from the 90° hybrid coupler 830, for example, by the GNSS band filter in the diplexer 880 or switch.

[0100] Thus, in a polarization configurable GNSS receiver, a user may use one linearly polarized antenna for GNSS to achieve superior accuracy under some conditions, such as conditions where there may not be a line-of-sight signal. A user may also configure the antenna for a circularly polarized GNSS receiver to achieve improved accuracy under some conditions, such as in an open, clear environment.

[0101] In some implementations, a smartphone or another portable device (e.g., a smartwatch) may include a software application that may determine whether it is appropriate to use a linearly polarized antenna or a circularly polarized antenna based on environmental conditions, device conditions, or other inputs. For example, the software application may periodically gather information about the environment, current device conditions, some user input, etc. by polling various sensors. In some examples, the sensors may report condition changes to the software application. Based on the collected or reported information, the software application may determine that a linearly polarized antenna or a circularly polarized antenna may be appropriate and may then control the diplexer 880 or a switch to connect or disconnect the second linearly polarized antenna (e.g., second linearly polarized antenna 820) and the 90° hybrid coupler (e.g., 90° hybrid coupler 830), for example, with little or no user involvement.

[0102] In one example, the antenna of the portable device may be operating in a linearly polarized mode (e.g., one linearly polarized antenna connected to a 90° hybrid coupler) before the software application determines that the portable device may be entering a high multipath environment. The software application may then determine that an RHCP antenna may be needed in the current environment because an RHCP antenna may have better multipath rejection capabilities than a linearly polarized antenna. The software application may then automatically connect a second linearly polarized antenna to a second port of the 90° hybrid coupler to form an RHCP antenna as described above. In another example, the software application may determine that it may be more appropriate to use a linearly polarized antenna in a particular operating condition, and therefore may disconnect one of the two linearly polarized antennas connected to the 90° hybrid coupler. In yet another example, the software application may determine that the portable device may be plugged into a power source, and therefore higher power consumption by the RHCP antenna may not be an issue, and may then automatically connect two linearly polarized antennas to the 90° hybrid coupler to form an RHCP antenna. The software application may determine the appropriate antenna operating mode based on some other parameter, criteria, rule, or policy.

[0103] In some GNSS receivers, the antenna may be switched between linear polarization mode and RHCP mode, for example, at startup, periodically, based on a predetermined schedule, or upon detection of a change in the environment. As described above, when the antenna is set in linear polarization mode (e.g., using a single linearly polarized antenna), the antenna may be able to detect both RHCP RF signals and LHCP RF signals. When the antenna is set in RHCP mode (e.g., using two orthogonal linearly polarized antennas and a 90° hybrid coupler as described above), the antenna may receive RHCP RF signals but reject LHCP RF signals. Thus, GNSS signals that are line-of-sight (LOS) signals or that are reflected an even number of times (and thus are still RHCP signals) may be received by the antenna in either linear polarization mode or RHCP mode.

[0104] However, in an environment with multipath GNSS signals that are reflected an odd number of times and thus become LHCP signals, the antenna can detect LHCP signals with a relatively high carrier-to-noise density ratio (C / N0) when the antenna is set in linear polarization mode, but cannot detect LHCP signals with a sufficiently high C / N0 when the antenna is set in RHCP mode. Thus, by measuring GNSS signals in the environment using antennas in both linear and circular polarization modes, the presence of an LHCP GNSS signal can be detected when a GNSS signal from a satellite is detected by an antenna in linear polarization mode if it has a sufficiently high C / N0, but is not detected by an antenna in RHCP mode even if it has a sufficiently high C / N0. Detection of an LHCP GNSS signal may indicate the presence of multipath GNSS signals or other non-line-of-sight (NLOS) GNSS signals in the environment. Additionally, a particular satellite whose signal is reflected an odd number of times and becomes an LHCP signal at the GNSS receiver may be identified based on information associated with the signal (e.g., the satellite's identity), and in some implementations the corresponding LHCP signal may not be used for positioning or may be given a low weight for positioning.

[0105] In one example, the antenna may first be set in a linear polarization mode (or RHCP mode) to perform one or more measurements. The antenna may then be configured for the RHCP mode (or linear polarization mode) as described above to perform one or more measurements. Based on the measurement results in the linear polarization mode and the RHCP mode, the LHCP NLOS signals and / or corresponding satellites may be identified as described above. The antenna may then be set in the linear polarization mode and new measurements may be taken. The GNSS receiver may determine a position fix based on the new measurements, where signals from the identified satellites may not be used for positioning or may be given a lower weight for positioning. Because the antenna may consume more power in the RHCP mode than in the linear polarization mode, operating the antenna in this manner may reduce overall power consumption while achieving a relatively high positioning accuracy since it does not rely on the LHCP NLOS signals to determine a position fix.

[0106] In some applications, higher position accuracy may be desired. The antenna may be set to an RHCP mode to reject NLOS signals, such as LHCP signals. In some environments, the majority of GNSS signals may be LHCP signals. An RHCP antenna may only be able to receive RHCP signals from a small number of satellites (e.g., fewer than three or four satellites), and thus the GNSS receiver may not be able to determine a position fix based on the received RHCP GNSS signals. In such environments, the antenna may be configured for a linearly polarized antenna to receive signals of more satellites for positioning.

[0107] Information determined by a GNSS receiver with configurable antennas described herein regarding the presence of NLOS signals in an environment and / or regarding satellites in the environment whose transmitted signals are LHCP signals may be used for other purposes. For example, a positioning system may use the information to estimate position error or positioning integrity, e.g., use a Stanford diagram to determine misleading information, misleading hazard information, or system unusable conditions. In some embodiments, the information may be crowdsourced or otherwise shared with other devices that may or may not have the capability to detect NLOS signals. In some embodiments, a GNSS receiver may determine that the GNSS receiver may not be able to receive LOS signals from a sufficiently large number of satellites (e.g., more than three or four) in a certain environment and may communicate with the positioning system so that the positioning system may use other techniques to determine a position fix. For example, the positioning system may choose to use other information, such as WiFi or WLAN signals rather than GNSS signals for positioning. In some embodiments, the positioning system may choose to use other techniques, such as dead reckoning techniques for positioning.

[0108] FIG. 9 is a flowchart 900 illustrating an example of a method for configuring a polarization configurable GNSS receiver according to some embodiments. It should be noted that the operations illustrated in FIG. 9 provide a particular positioning technique that detects and mitigates the effects of spoofing signals on positioning. Other sequences of operations may also be performed according to alternative embodiments. For example, alternative embodiments may perform the operations in a different order. Additionally, each operation illustrated in FIG. 9 may include multiple sub-operations that may be performed in various sequences as appropriate for each operation. Additionally, some operations may be added or removed depending on the particular application. In some implementations, two or more operations may be performed in parallel. Those skilled in the art will recognize many variations, modifications, and alternatives. In various embodiments, the means for performing the functions illustrated in the flowchart 900 may include, for example, a GNSS receiver and / or a processing unit on a UE or vehicle as described herein, which may include hardware and / or software components for performing the described functions. For example, the means for performing the operations in flowchart 900 may include various components of a GNSS receiver or UE, such as a PIFA, a 90° hybrid coupler, an n-plexer (e.g., a diplexer, extractor, or switch), a tuner, an RF front-end circuit, an IF / BB signal processing section, and / or a navigation engine of GNSS receiver 300, GNSS receiver 600, 700, or 800, or the antenna 1082, GNSS receiver 1080, processing unit 1010, bus 1005, and memory 1060 of UE 105 shown in FIG. 10 below.

[0109] In block 910, a first antenna of the portable device (e.g., a smartphone) may receive a first linearly polarized component of the GNSS signal. The first antenna may include a PIFA antenna or another antenna having a small footprint and low height profile. The first antenna may be a linearly polarized antenna, such as a vertically linearly polarized antenna configured to receive a vertically linearly polarized RF signal. In some embodiments, the first antenna may also receive an RF signal in a second wireless communication technology, such as a WWAN technology (e.g., GSM, CDMA, LTE, 5G NR, or WiMAX), a WLAN technology (e.g., WiFi), or a WPAN technology (e.g., Bluetooth or ZigBee). An n-plexer, such as a diplexer or extractor, may be used to separate the first linearly polarized component of the GNSS signal and the RF signal in the second wireless communication technology.

[0110] In block 920, the tuner may tune a second antenna of the portable device to the GNSS band. The second antenna may also be a PIFA or a linearly polarized antenna. The tuner may include, for example, an aperture tuner or an impedance tuner that can tune a resonant frequency of the second antenna to the GNSS band or another frequency band for a different wireless communication technology, such as another WWAN, WLAN, WPAN technology. The tuner may tune the second antenna to the GNSS band, for example, when the portable device is in an open sky environment or a clear environment.

[0111] At block 930, a second antenna tuned to the GNSS band may receive a second linearly polarized component of the GNSS signal. The second linearly polarized component of the GNSS signal may include, for example, a horizontal linearly polarized component of the GNSS signal. In some embodiments, the second antenna may be tuned to both the GNSS band and a frequency band for a different wireless communication technology, and an n-plexer (e.g., a diplexer or extractor) may be used to separate the second linearly polarized component of the GNSS signal and the RF signal of the different wireless communication technology.

[0112] In block 940, the hybrid coupler (e.g., a 90° hybrid coupler) may combine the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal to generate a composite (e.g., circularly polarized) GNSS signal. The composite GNSS signal may have a power that is approximately 3 dB higher than the power of the first linearly polarized component of the GNSS signal or the second linearly polarized component of the GNSS signal. Thus, the first antenna, the second antenna, and the hybrid coupler may form a circularly polarized antenna, which may also reject LHCP signals resulting from reflections of RHCP signals transmitted by GNSS satellites. As a result, a more accurate position fix of the portable device may be determined by the GNSS receiver. The hybrid coupler may include, for example, a branch-line coupler, a Lange coupler, an overlay coupler, an edge coupler, or a short-slot hybrid coupler.

[0113] Optionally, the hybrid coupler may provide the composite GNSS signal to a radio frequency front-end circuit of the portable device in block 950. In some embodiments, an n-plexer, such as a diplexer or triplexer, may separate the GNSS signals in different bands, such as the L1, L5, and / or L2 bands, and then send the GNSS signals in the different bands to the radio frequency front-end circuit.

[0114] Optionally, in block 960, the tuner may tune the second antenna to a frequency band for a second wireless communication technology, for example, when a good position fix is ​​sufficient for the user application. In block 970, a switch or filter (e.g., a filter in a diplexer) may disconnect or isolate the second antenna from the hybrid coupler such that the hybrid coupler cannot receive signals from the second antenna. Thus, the first antenna and the hybrid coupler may function as a linearly polarized GNSS receiver. In block 980, the hybrid coupler may provide the first linearly polarized component of the GNSS signal to a radio frequency front-end circuit of the portable device. In this way, the first antenna, the second antenna (including the tuner and / or the n-plexer), and the hybrid coupler may form a polarization configurable GNSS receiver that may be tuned to receive a circularly polarized GNSS signal or a linearly polarized component of the GNSS signal based on the environment, a particular use case, or a desired accuracy.

[0115] FIG. 10 illustrates one embodiment of a UE 105 that may be utilized as described herein above (e.g., in conjunction with FIGS. 1-9). For example, the UE 105 may perform one or more of the functions of the method illustrated in FIG. 9. It should be noted that FIG. 10 is only intended to provide a generalized view of various components, any or all of which may be utilized as appropriate. It may be noted that in some instances, the components illustrated by FIG. 10 may be localized in a single physical device and / or distributed among various networked devices that may be disposed in different physical locations. Additionally, as previously mentioned, the functionality of the UE discussed in the previously described embodiments may be performed by one or more of the hardware and / or software components illustrated in FIG. 10.

[0116] A UE 105 is shown comprising hardware elements that may be electrically coupled (or in some cases in communication as appropriate) via a bus 1005. The hardware elements may include a processing unit 1010, which may include, but is not limited to, one or more general-purpose processors, one or more special-purpose processors (such as DSP chips, graphics acceleration processors, application specific integrated circuits (ASICs), etc.), and / or other processing structures or means. As shown in FIG. 10, some embodiments may have a separate DSP 1020 depending on the desired functionality. Location determination and / or other determinations based on wireless communication may be performed in the processing unit 1010 and / or in the wireless communication interface 1030 (discussed below). The UE 105 may also include one or more input devices 1070, which may include, but is not limited to, one or more keyboards, touch screens, touch pads, microphones, buttons, dials, switches, etc., and one or more output devices 1015, which may include, but is not limited to, one or more displays (e.g., touch screens), light emitting diodes (LEDs), speakers, etc.

[0117] The UE 105 may also include a wireless communication interface 1030, which may comprise, but is not limited to, a modem, a network card, an infrared communication device, a wireless communication device, and / or a chipset (such as a Bluetooth device, an IEEE 802.11 device, an IEEE 802.15.4 device, a Wi-Fi device, a WiMAX device, a WAN device, and / or various cellular devices), and the like, which may enable the UE 105 to communicate with other devices as described in the above embodiments. Thus, the wireless communication interface 1030 may include RF circuitry capable of tuning between one or additional bands having one or more FLs used for active BWP and PRS signals, as described herein. The wireless communication interface 1030 may enable data and signaling to be communicated (e.g., transmitted and received) with the TRP of the network, as described herein, for example, via eNBs, gNBs, ng-eNBs, access points, various base stations and / or other access node types, and / or other network components, computer systems, and / or any other electronic devices communicatively coupled to the TRP. Communications may be performed via one or more wireless communication antennas 1032 that send and / or receive wireless signals 1034. According to some embodiments, the wireless communication antenna 1032 may include multiple individual antennas, an antenna array, or any combination thereof.

[0118] Depending on the desired functionality, the wireless communication interface 1030 may comprise separate receivers and transmitters, or any combination of transceivers, transmitters, and / or receivers, for communicating with base stations (e.g., ng-eNBs and gNBs) and other terrestrial transceivers, such as wireless devices and access points. The UE 105 may communicate with different data networks, which may include a variety of network types. For example, a wireless wide area network (WWAN) may be a CDMA network, a time division multiple access (TDMA) network, a frequency division multiple access (FDMA) network, an orthogonal frequency division multiple access (OFDMA) network, a single carrier frequency division multiple access (SC-FDMA) network, a WiMAX (IEEE 802.16) network, etc. The CDMA network may implement one or more RATs, such as CDMA2000, WCDMA, etc. CDMA2000 includes IS-95, IS-2000, and / or IS-856 standards. The TDMA network may implement GSM, Digital Advanced Mobile Phone System (D-AMPS), or some other RAT. The OFDMA network may employ LTE, LTE Advanced, 5G NR, etc. 5G NR, LTE, LTE Advanced, GSM, and WCDMA are described in documents from 3GPP. Cdma2000 is described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). 3GPP and 3GPP2 documents are publicly available. The WLAN may also be an IEEE 802.11x network, and the wireless personal area network (WPAN) may be a Bluetooth network, an IEEE 802.15x, or some other type of network. The techniques described herein may also be used for any combination of WWAN, WLAN, and / or WPAN.

[0119] The UE 105 may further include sensors 1040. The sensors 1040 may include, but are not limited to, one or more inertial sensors and / or other sensors (e.g., accelerometers, gyroscopes, cameras, magnetometers, altimeters, microphones, proximity sensors, light sensors, barometers, etc.), some of which may be used to obtain location-related measurements and / or other information.

[0120] An embodiment of the UE 105 may also include a Global Navigation Satellite System (GNSS) receiver 1080 capable of receiving signals 1084 from one or more GNSS satellites using an antenna 1082 (which may be the same as the wireless communication antenna 1032). Positioning based on GNSS signal measurements may be utilized to complement and / or incorporate the techniques described herein. The GNSS receiver 1080 may use conventional techniques to extract a position of the UE 105 from GNSS satellites 110 of a GNSS system such as Global Positioning System (GPS), Galileo, GLONASS, Quasi-Zenith Satellite System (QZSS) over Japan, Indian Regional Navigation Satellite System (IRNSS) over India, and BeiDou Navigation Satellite System (BDS) over China. Furthermore, the GNSS receiver 1080 may be used with various augmentation systems (e.g., Satellite-Based Augmentation Systems (SBAS)), which may be associated with or otherwise enabled for use with one or more global and / or regional navigation satellite systems, such as, for example, the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), the Multifunction Satellite Augmentation System (MSAS), and the Geo-Augmented Navigation System (GAGAN).

[0121] It may be noted that although the GNSS receiver 1080 is shown in FIG. 10 as a separate component, the embodiment is not so limited. As used herein, the term “GNSS receiver” may include hardware and / or software components configured to obtain GNSS measurements (measurements from GNSS satellites). Thus, in some embodiments, the GNSS receiver may comprise a measurement engine executed (as software) by one or more processing units, such as the processing unit 1010, the DSP 1020, and / or a processing unit (e.g., in a modem) in the wireless communication interface 1030. The GNSS receiver may also optionally include a positioning engine, which may use the GNSS measurements from the measurement engine to determine the position of the GNSS receiver using an extended Kalman filter (EKF), weighted least squares (WLS), a hatch filter, a particle filter, etc. The positioning engine may also be executed by one or more processing units, such as the processing unit 1010 or the DSP 1020.

[0122] The UE 105 may further include and / or be in communication with a memory 1060. The memory 1060 may include, but is not limited to, local and / or network accessible storage, disk drives, drive arrays, optical storage devices, solid-state storage devices such as random access memory (RAM) and / or read-only memory (ROM) that may be programmable, flash updatable, etc. Such storage devices may be configured to implement any suitable data store, including, but not limited to, various file systems, database structures, etc.

[0123] The memory 1060 of the UE 105 may also comprise software elements (not shown in FIG. 10) including other code, such as an operating system, device drivers, executable libraries, and / or one or more application programs, which may include computer programs provided by various embodiments as described herein and / or may be designed to implement methods and / or configure systems provided by other embodiments. By way of example only, one or more procedures described with respect to the methods discussed above may be implemented as code and / or instructions in the memory 1060 executable by the UE 105 (and / or the processing unit 1010 or DSP 1020 within the UE 105). In one aspect, such code and / or instructions may then be used to configure and / or adapt a general-purpose computer (or other device) to perform one or more operations in accordance with the methods described.

[0124] Figure 11 illustrates one embodiment of a TRP 1100 that may be utilized as described herein above (e.g., in connection with Figures 1-6). It should be noted that Figure 11 is intended only to provide a generalized view of various components, any or all of which may be utilized as appropriate.

[0125] The TRP 1100 is shown with hardware elements that may be electrically coupled (or in some cases may be in communication as appropriate) via a bus 1105. The hardware elements may include a processing unit 1110, which may include, but is not limited to, one or more general-purpose processors, one or more special-purpose processors (such as DSP chips, graphics acceleration processors, ASICs, etc.), and / or other processing structures or means. As shown in FIG. 11, some embodiments may have a separate DSP 1120 depending on the desired functionality. Location determination and / or other determinations based on wireless communication may be performed in the processing unit 1110 and / or in the wireless communication interface 1130 (discussed below), according to some embodiments. The TRP 1100 may also include one or more input devices, which may include, but are not limited to, a keyboard, a display, a mouse, a microphone, buttons, dials, switches, etc., and one or more output devices, which may include, but are not limited to, a display, a light-emitting diode (LED), a speaker, etc.

[0126] The TRP 1100 may also include a wireless communication interface 1130, which may comprise, but is not limited to, a modem, a network card, an infrared communication device, a wireless communication device, and / or a chipset (such as a Bluetooth device, an IEEE 802.11 device, an IEEE 802.15.4 device, a Wi-Fi device, a WiMAX device, a cellular communication facility, etc.), which may enable the TRP 1100 to communicate as described herein. The wireless communication interface 1130 may enable data and signaling to be communicated (e.g., transmitted and received) to a UE, other base stations / TRPs (e.g., eNBs, gNBs, and ng-eNBs), and / or other network components, computer systems, and / or any other electronic devices described herein. The communication may be performed via one or more wireless communication antennas 1132 that send and / or receive wireless signals 1134.

[0127] The TRP 1100 may also include a network interface 1180, which may include support for wireline communication technologies. The network interface 1180 may include a modem, a network card, a chipset, etc. The network interface 1180 may include one or more input and / or output communication interfaces to allow data to be exchanged with a network, a communication network server, a computer system, and / or any other electronic device described herein.

[0128] In many embodiments, the TRP 1100 may further comprise a memory 1160. The memory 1160 may include, but is not limited to, local and / or network accessible storage, disk drives, drive arrays, optical storage devices, solid-state storage devices such as RAM and / or ROM that may be programmable, flash updatable, etc. Such storage devices may be configured to implement any suitable data store, including, but not limited to, various file systems, database structures, etc.

[0129] The memory 1160 of the TRP 1100 may also comprise software elements (not shown in FIG. 11 ) including other code, such as an operating system, device drivers, executable libraries, and / or one or more application programs, which may include computer programs provided by various embodiments as described herein and / or may be designed to implement methods and / or configure systems provided by other embodiments. By way of example only, one or more procedures described with respect to the methods discussed above may be implemented as code and / or instructions in the memory 1160 executable by the TRP 1100 (and / or the processing unit 1110 or DSP 1120 within the TRP 1100). In one aspect, such code and / or instructions may then be used to configure and / or adapt a general-purpose computer (or other device) to perform one or more operations according to the methods described.

[0130] FIG. 12 is a block diagram of an embodiment of a computer system 1200 that may be used in whole or in part to provide the functionality of one or more network components (e.g., location server 160 of FIG. 1, LMF 220 of FIG. 2, etc.) as described in the embodiments herein. It should be noted that FIG. 12 is only intended to provide a generalized view of the various components, any or all of which may be utilized as appropriate. Thus, FIG. 12 broadly illustrates how individual system elements may be implemented in a relatively separated or relatively more integrated manner. In addition, it may be noted that the components illustrated by FIG. 12 may be localized in a single device and / or distributed among various networked devices that may be disposed in different geographic locations.

[0131] A computer system 1200 is shown comprising hardware elements that may be electrically coupled (or in some cases may be in communication as appropriate) via a bus 1205. The hardware elements may include a processing unit 1210, which may include, but is not limited to, one or more general purpose processors, one or more special purpose processors (such as digital signal processing chips, graphics acceleration processors, etc.), and / or other processing structures that may be configured to perform one or more of the methods described herein. The computer system 1200 may also include one or more input devices 1215, which may include, but is not limited to, a mouse, a keyboard, a camera, a microphone, etc., and one or more output devices 1220, which may include, but is not limited to, a display device, a printer, etc.

[0132] The computer system 1200 may further include (and / or be in communication with) one or more non-transitory storage devices 1225, which may include, but are not limited to, local and / or network accessible storage and / or solid-state storage devices, such as, but not limited to, disk drives, drive arrays, optical storage devices, RAM and / or ROM, which may be programmable, flash updatable, etc. Such storage devices may be configured to implement any suitable data store, including, but not limited to, various file systems, database structures, etc. Such data stores may include databases and / or other data structures used to store and manage messages and / or other information to be sent to one or more devices via the hub, as described herein.

[0133] The computer system 1200 may also include a communication subsystem 1230, which may include wireless communication technologies managed and controlled by a wireless communication interface 1233, as well as wired technologies (such as Ethernet, coaxial communication, Universal Serial Bus (USB)). The wireless communication interface 1233 may send and receive wireless signals 1255 (e.g., signals according to 5G NR or LTE) via a wireless antenna 1250. Thus, the communication subsystem 1230 may include a modem, a network card (wireless or wired), an infrared communication device, a wireless communication device, and / or a chipset, etc., which may enable the computer system 1200 to communicate in any or all of the communication networks described herein to any device on the respective network, including a user equipment (UE), a base station and / or other TRP, and / or any other electronic device described herein. Thus, the communication subsystem 1230 may be used to receive and send data as described in the embodiments herein.

[0134] In many embodiments, the computer system 1200 further comprises a working memory 1235, which may include a RAM device or a ROM device, as described above. The software elements shown as being located in the working memory 1235 may include other code, such as an operating system 1240, device drivers, executable libraries, and / or one or more applications 1245, which may include computer programs provided by various embodiments as described herein and / or may be designed to implement methods provided by other embodiments and / or configure systems provided by other embodiments. By way of example only, one or more procedures described with respect to the methods discussed above may be implemented as code and / or instructions executable by a computer (and / or a processing unit within a computer), and in one aspect, such code and / or instructions may then be used to configure and / or adapt a general-purpose computer (or other device) to perform one or more operations in accordance with the methods described.

[0135] A set of these instructions and / or code may be stored on a non-transitory computer-readable storage medium, such as storage device 1225 described above. In some cases, the storage medium may be incorporated within a computer system, such as computer system 1200. In other embodiments, the storage medium may be separate from the computer system (e.g., a removable medium, such as an optical disk) and / or provided in an installation package, such that the storage medium may be used to program, configure, and / or adapt a general-purpose computer with the instructions / code stored thereon. These instructions may take the form of executable code that is executable by computer system 1200 and / or may take the form of source and / or installable code that, when compiled and / or installed on computer system 1200 (e.g., using any of a variety of commonly available compilers, installation programs, compression / decompression utilities, etc.), is then in the form of executable code.

[0136] It will be apparent to those skilled in the art that substantial variations may be made according to particular requirements. For example, customized hardware may also be used and / or particular elements may be implemented in hardware, software (including portable software such as applets), or both. Furthermore, connection to other computing devices, such as network input / output devices, may be employed.

[0137] With reference to the accompanying figures, components that may include memory may include non-transitory machine-readable media. As used herein, the terms "machine-readable media" and "computer-readable media" refer to any storage medium that participates in providing data that causes a machine to operate in a specific manner. In the embodiments provided above, various machine-readable media may participate in providing instructions / code to a processing unit and / or other devices for execution. Additionally or alternatively, machine-readable media may be used to store and / or transport such instructions / code. In many implementations, the computer-readable media is a physical and / or tangible storage medium. Such media may take many forms, including but not limited to non-volatile media, volatile media, and transmission media. Common forms of computer-readable media include, for example, magnetic media and / or optical media, any other physical media with a pattern of holes, RAM, programmable ROM (PROM), erasable PROM (EPROM), FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described below, or any other medium from which a computer can read instructions and / or code.

[0138] The methods, systems, and devices discussed herein are examples. Various embodiments may omit, substitute, or add various procedures or components, as appropriate. For example, features described with respect to some embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. Various components of the diagrams provided herein may be embodied in hardware and / or software. Also, technology evolves, and thus many of the elements are examples that do not limit the scope of the disclosure to those specific examples.

[0139] It has proven convenient at times, primarily for reasons of common usage, to refer to such signals as bits, information, values, elements, symbols, characters, variables, terms, numbers, numeric values, or the like. It should be understood, however, that all of these or similar terms are to be associated with the appropriate physical quantities and are merely convenient labels. Unless otherwise indicated, and as is apparent from the above description, it will be appreciated that throughout this specification, descriptions utilizing terms such as "processing," "calculating," "calculating," "determining," "ascertaining," "identifying," "associating," "measuring," "performing," and the like refer to the actions or processes of a particular apparatus, such as a special purpose computer or similar special purpose electronic computing device. Thus, in the context of this specification, a special purpose computer or similar special purpose electronic computing device is capable of manipulating or transforming signals that are commonly represented as electronic, electrical, or magnetic physical quantities in memories, registers, or other information storage, transmission, or display devices of the special purpose computer or similar special purpose electronic computing device.

[0140] The terms "and" and "or" as used herein may include various meanings that are also expected to depend at least in part on the context in which such terms are used. Typically, "or," when used to associate a list such as A, B, or C, is intended to mean A, B, and C, which are used herein in an inclusive sense, as well as A, B, or C, which are used herein in an exclusive sense. In addition, the term "one or more" as used herein may be used to represent any feature, structure, or characteristic in the singular, or may be used to represent any combination of features, structures, or characteristics. However, it should be noted that this is merely an illustrative example, and claimed subject matter is not limited to this example. Furthermore, the term "at least one of," when used to associate a list such as A, B, or C, may be interpreted to mean A, B, C, or any (reasonable) combination of A, B, and / or C, such as AC, AB, BC, AA, AAB, ABC, AABBCCC, etc.

[0141] Although several embodiments have been described, various modifications, alternative configurations, and equivalents may be used without departing from the spirit of the present disclosure. For example, the above elements may simply be components of a larger system, where other rules may take precedence over or otherwise modify the application of the various embodiments. Also, some steps may be undertaken before, during, or after the above elements are considered. Thus, the above description does not limit the scope of the present disclosure.

[0142] In light of this description, embodiments may include different combinations of features. Example implementations are described in the following numbered clauses. Clause 1: A Global Navigation Satellite System (GNSS) receiver comprising: a first linearly polarized antenna configured to receive a first linearly polarized component of a GNSS signal; a second linearly polarized antenna configurable to receive a second linearly polarized component of the GNSS signal, a radio frequency signal conforming to a second wireless communication technology, or both; and a hybrid coupler including a first port electrically coupled to the first linearly polarized antenna, a second port electrically coupled to the second linearly polarized antenna, and a third port outputting a composite GNSS signal of the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal, wherein a difference between a phase delay from the second port to the third port and a phase delay from the first port to the third port is between 60° and 120°. Clause 2: The GNSS receiver of clause 1, wherein the first linearly polarized antenna and the second linearly polarized antenna are planar inverted-F antennas. Clause 3: A GNSS receiver of any of clauses 1 to 2, wherein a first linearly polarized antenna is configured to receive a radio frequency signal conforming to a third wireless communications technology, and the GNSS receiver comprises a demultiplexing circuit coupled to the first linearly polarized antenna and configured to separate the first linearly polarized component of the GNSS signal and the radio frequency signal conforming to the third wireless communications technology. Clause 4: The GNSS receiver of clause 3, wherein the demultiplexing circuitry comprises an n-plexer, where n is greater than 1. Clause 5: The GNSS receiver of clause 3, wherein the demultiplexing circuit comprises a first bandpass filter configured to select a first linear polarization component of the GNSS signal and a second bandpass filter configured to select a radio frequency signal compliant with a third wireless communications technology. Clause 6: A GNSS receiver of any of clauses 1 to 5, wherein the second linearly polarized antenna comprises a tuner configured to tune a resonant frequency of the second linearly polarized antenna to receive a second linearly polarized component of a GNSS signal, a radio frequency signal compliant with a second wireless communications technology, or both. Clause 7: The GNSS receiver of clause 6, wherein the tuner comprises an aperture tuner or an impedance tuner. Clause 8: A GNSS receiver of any of clauses 1 to 7, further comprising a switch between the second linearly polarized antenna and the second port of the hybrid coupler, the switch being configurable to connect or disconnect the second linearly polarized antenna and the hybrid coupler. Clause 9: A GNSS receiver of any of clauses 1 to 7, further comprising an n-plexer between the second linearly polarized antenna and the second port of the hybrid coupler, the n-plexer configured to separate the second linearly polarized component of the GNSS signal from a radio frequency signal conforming to the second wireless communication technology, and send the second linearly polarized component of the GNSS signal to the second port of the hybrid coupler. Clause 10: The GNSS receiver of any of clauses 1 to 9, further comprising an n-plexer coupled to a third port of the hybrid coupler and configured to separate the GNSS L1 signal and the GNSS L5 signal. Clause 11: The GNSS receiver of any of clauses 1 to 10, wherein the second wireless communication technology includes a wireless wide area network (WWAN) technology, a wireless local area network (WLAN) technology, or a wireless personal area network (WPAN) technology. Clause 12: A GNSS receiver of any of clauses 1 to 11, wherein the first linearly polarized antenna includes a vertically linearly polarized antenna and the second linearly polarized antenna includes a horizontally linearly polarized antenna. Clause 13: A GNSS receiver according to any one of clauses 1 to 12, wherein the third port of the hybrid coupler outputs a right-hand circularly polarized GNSS signal. Clause 14: A method comprising the steps of receiving a first linearly polarized component of a GNSS signal by a first antenna of a portable device, tuning a second antenna of the portable device to a GNSS band, receiving a second linearly polarized component of the GNSS signal by the second antenna, and combining by a hybrid coupler the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal to generate a composite GNSS signal. Clause 15: The method of clause 14, further comprising the steps of tuning a second antenna to a frequency band for a second wireless communications technology different from the GNSS technology, disconnecting the second antenna from the hybrid coupler by a switch or filter, and supplying the composite GNSS signal or the first linearly polarized component of the GNSS signal to a radio frequency front-end circuit of the portable device. Clause 16: The method of clause 15, wherein the second wireless communications technology includes a wireless wide area network (WWAN) technology, a wireless local area network (WLAN) technology, or a wireless personal area network (WPAN) technology. Clause 17: The method of clause 14, wherein the step of tuning the second antenna includes the step of tuning the second antenna to receive both the second linearly polarized component of the GNSS signal and the radio frequency signal compliant with the second wireless communications technology, and the method further includes the step of separating the second linearly polarized component of the GNSS signal and the radio frequency signal compliant with the second wireless communications technology. Clause 18: The method of clause 14, further comprising the steps of receiving, by a first antenna, a radio frequency signal conforming to a third wireless communications technology, and separating the first linearly polarized component of the GNSS signal and the radio frequency signal conforming to the third wireless communications technology. Clause 19: The method of clause 18, wherein the third wireless communications technology includes a wireless wide area network (WWAN) technology, a wireless local area network (WLAN) technology, or a wireless personal area network (WPAN) technology. Clause 20: Any of the methods of clauses 14 to 19, wherein the step of combining the first linear polarization component of the GNSS signal and the second linear polarization component of the GNSS signal includes a step of delaying the second linear polarization component of the GNSS signal by a phase delay of within +90±30° or within -90±30° relative to the first linear polarization component of the GNSS signal. Clause 21: The method of any of clauses 14 to 20, further comprising automatically switching a switch between the second antenna and the hybrid coupler to connect or disconnect the second antenna and the hybrid coupler based on environmental conditions, operating conditions, or both of the portable device. Clause 22: The method of any of clauses 14 to 21, further comprising the steps of disconnecting the second antenna from the hybrid coupler, measuring a first set of one or more GNSS signals using the first antenna, connecting the second antenna to the hybrid coupler, measuring a second set of one or more GNSS signals using the first antenna and the second antenna, and identifying GNSS signals that are within the first set of one or more GNSS signals but not within the second set of one or more GNSS signals as multipath GNSS signals. Clause 23. The method of clause 22, further comprising identifying a first satellite associated with the multipath GNSS signal. Clause 24: The method of clause 23, further comprising the steps of disconnecting the second antenna from the hybrid coupler, measuring a third set of GNSS signals using the first antenna, the third set of GNSS signals including the GNSS signals from the first satellite, and determining a location fix based on the third set of GNSS signals excluding the GNSS signals from the first satellite. Clause 25: A portable device comprising: means for receiving a first linearly polarized component of a Global Navigation Satellite System (GNSS) signal; means for tuning an antenna of the portable device to a GNSS band to receive a second linearly polarized component of the GNSS signal; and means for combining the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal to generate a circularly polarized GNSS signal. Clause 26: The portable device of clause 25, further comprising means for tuning the antenna to a frequency band for a second wireless communications technology different from the GNSS technology, means for disconnecting the antenna from the means for combining the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal, and means for supplying the first linearly polarized component of the GNSS signal or the circularly polarized GNSS signal to a radio frequency front-end circuitry of the portable device. Clause 27: The portable device of clause 26, wherein the second wireless communications technology includes a wireless wide area network (WWAN) technology, a wireless local area network (WLAN) technology, or a wireless personal area network (WPAN) technology. Clause 28: The portable device of clause 25, wherein the means for tuning the antenna comprises means for tuning the antenna to both the GNSS band and a frequency band for a second wireless communications technology, and the portable device further comprises means for separating a second linearly polarized component of the GNSS signal and a radio frequency signal compliant with the second wireless communications technology. Clause 29: The portable device of clause 25, wherein the means for receiving the first linearly polarized component of the GNSS signal is further configured to receive a radio frequency signal conforming to a second wireless communication technology, and the portable device further comprises means for separating the first linearly polarized component of the GNSS signal and the radio frequency signal conforming to the second wireless communication technology. Clause 30: A Global Navigation Satellite System (GNSS) receiver comprising: a first linearly polarized antenna configured to receive a first linearly polarized component of a GNSS signal; a second linearly polarized antenna; a tuner configurable to tune the second linearly polarized antenna to a GNSS band to receive the second linearly polarized component of the GNSS signal; and a hybrid coupler configured to combine the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal to generate a circularly polarized GNSS signal. Clause 31: The GNSS receiver of clause 30, wherein the tuner is configurable to tune the second linearly polarized antenna to a frequency band for a second wireless communications technology different from the GNSS technology, and the GNSS receiver further comprises a switch or filter configured to disconnect the second linearly polarized antenna from the hybrid coupler. Clause 32: The GNSS receiver of clause 30, wherein the tuner is configurable to tune the second linearly polarized antenna to receive both the second linearly polarized component of the GNSS signal and the radio frequency signal conforming to the second wireless communications technology, and the GNSS receiver comprises an n-plexer configured to separate the second linearly polarized component of the GNSS signal and the radio frequency signal conforming to the second wireless communications technology. Clause 33: The GNSS receiver of clause 30, wherein the first linearly polarised antenna is configured to receive a radio frequency signal conforming to a second wireless communication technology, and the GNSS receiver comprises an n-plexer configured to separate the first linearly polarised component of the GNSS signal and the radio frequency signal conforming to the second wireless communication technology. [Explanation of symbols]

[0143] 100 Positioning System 105UE 110 GNSS satellites 120 base station 130 Access Point (AP), AP 133 First communication link 135 Secondary Communication Link 160 Location Server 170 Network 180 external clients 300 GNSS Receiver 310 Antenna 320 Radio Frequency (RF) Front End, RF Front End 322 Pre-filter 324 Preamplifier 326 Down Converter 328 Local Oscillator 330 Intermediate frequency (IF) / baseband (BB) signal processing section, IF / BB signal processing section 332 Analog to Digital Converter, ADC 334 Acquisition Module 336 Tracking Unit 338 Automatic Gain Control (AGC) Stage 340 Navigation Engine 400 Smartphones 405 PIFA 450 tail 452 Ground Plane 454 Section 456 Section 510 Circularly polarized electrical signal 512 First Component 514 Second Component 550 Charts 552 Charts 600 Circularly polarized GNSS receiver, GNSS receiver 610 First linearly polarized antenna 620 Second Linearly Polarized Antenna 630 90° Hybrid Coupler 640 RF Front End 650 90° Hybrid Coupler 700 Circularly polarized GNSS receiver, GNSS receiver 710 First linearly polarized antenna 720 Second Linearly Polarized Antenna 730 90° Hybrid Coupler 732 resistor 740 RF Front End 750 Diplexer 752 Filters 754 Filter 800 Polarization Configurable GNSS Receiver, GNSS Receiver 810 First linearly polarized antenna 820 Second Linearly Polarized Antenna 830 90° Hybrid Coupler 832 resistor 840 RF Frontend 850 Diplexer 860 Extractor 870 Tuner 880 Diplexer 900 Flowchart 1005 Bus 1010 Processing unit 1015 Output Device 1020 DSP 1030 Wireless communication interface 1032 Wireless communication antenna 1034 Wireless Signal 1040 Sensor 1060 Memory 1070 Input Device 1080 Global Navigation Satellite System (GNSS) Receiver, GNSS Receiver 1082 Antenna 1084 signal 1100 TRP 1105 Bus 1110 Processing Unit 1120 DSP 1130 Wireless communication interface 1132 Wireless Communication Antenna 1134 Wireless Signal 1160 Memory 1180 Network Interface 1200 Computer Systems 1205 Bus 1210 Processing Unit 1215 Input Devices 1220 output device 1225 Non-transient storage devices, storage devices 1230 Communication Subsystem 1233 Wireless Communication Interface 1235 Working Memory 1240 Operating Systems 1245 Applications 1250 Wireless Antenna 1255 Wireless Signal

Claims

1. 1. A Global Navigation Satellite System (GNSS) receiver, comprising: a first linearly polarized antenna configured to receive radio frequency signals conforming to a first wireless communication technology, the radio frequency signals conforming to the first wireless communication technology including a first linearly polarized component of a GNSS signal; a second linearly polarized antenna configurable to receive a second linearly polarized component of the GNSS signal and a radio frequency signal conforming to a second wireless communications technology; 1. A hybrid coupler, comprising: a first port electrically coupled to the first linearly polarized antenna; a second port electrically coupled to the second linearly polarized antenna; a third port configured to output a combined GNSS signal of the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal; a hybrid coupler, wherein a difference between a phase delay from the second port to the third port and a phase delay from the first port to the third port is between 60° and 120°; an n-plexer between the second linearly polarized antenna and the second port of the hybrid coupler, Separating the second linearly polarized component of the GNSS signal and the radio frequency signal compliant with the second wireless communications technology; Sending the second linearly polarized component of the GNSS signal to the second port of the hybrid coupler. The n-plexer is configured as 1. A GNSS receiver comprising:

2. 2. The GNSS receiver of claim 1, wherein the first linearly polarized antenna and the second linearly polarized antenna are planar inverted-F antennas.

3. the first linearly polarized antenna is configured to receive radio frequency signals conforming to a third wireless communications technology; The GNSS receiver, a demultiplexing circuit coupled to the first linearly polarized antenna and configured to separate the first linearly polarized component of the GNSS signal and the radio frequency signal compliant with the third wireless communication technology. GNSS receiver according to claim 1.

4. 4. The GNSS receiver of claim 3, wherein the demultiplexing circuit comprises an n-plexer, where n is greater than 1.

5. 4. The GNSS receiver of claim 3, wherein the demultiplexing circuit comprises a first bandpass filter configured to select the first linear polarization component of the GNSS signal and a second bandpass filter configured to select the radio frequency signal compliant with the third wireless communication technology.

6. 2. The GNSS receiver of claim 1, wherein the second linearly polarized antenna comprises a tuner configured to tune a resonant frequency band of the second linearly polarized antenna to receive the second linearly polarized component of the GNSS signal, the radio frequency signal compliant with the second wireless communication technology, or both.

7. The GNSS receiver of claim 6 , wherein the tuner comprises an aperture tuner or an impedance tuner.

8. 2. The GNSS receiver of claim 1, further comprising a switch between the second linearly polarized antenna and the second port of the hybrid coupler, the switch being configurable to connect or disconnect the second linearly polarized antenna and the hybrid coupler.

9. 2. The GNSS receiver of claim 1, further comprising an n-plexer coupled to the third port of the hybrid coupler and configured to separate a GNSS L1 signal and a GNSS L5 signal.

10. 10. The GNSS receiver of claim 1, wherein the second wireless communication technology comprises a wireless wide area network (WWAN) technology, a wireless local area network (WLAN) technology, or a wireless personal area network (WPAN) technology.

11. the first linearly polarized antenna comprises a vertically polarized antenna; the second linearly polarized antenna comprises a horizontally polarized antenna; GNSS receiver according to claim 1.

12. The GNSS receiver of claim 1 , wherein the third port of the hybrid coupler outputs a right-hand circularly polarized GNSS signal.

13. receiving, by a first antenna of the portable device, a first linearly polarized component of a Global Navigation Satellite System (GNSS) signal; tuning a second antenna of the portable device to a GNSS band, the tuning including tuning to receive both a second linearly polarized component of the GNSS signal and a radio frequency signal compliant with a second wireless communications technology; receiving, by the second antenna, a second linearly polarized component of the GNSS signal and the radio frequency signal conforming to the second wireless communication technology; sending the first linearly polarized component of the GNSS signal to a hybrid coupler; separating the second linearly polarized component of the GNSS signal from the radio frequency signal conforming to the second wireless communication technology by an n-plexer between the second antenna and the hybrid coupler, and sending the second linearly polarized component of the GNSS signal to the hybrid coupler; combining, by a hybrid coupler, the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal to generate a circularly polarized GNSS signal; The method includes:

14. 1. A Global Navigation Satellite System (GNSS) receiver, comprising: a first linearly polarized antenna configured to receive a first linearly polarized component of a GNSS signal; a second linearly polarized antenna; and a tuner configurable to tune the second linearly polarized antenna to a GNSS band to receive a second linearly polarized component of the GNSS signal and a radio frequency signal conforming to a second wireless communications technology; a hybrid coupler configured to combine the first linearly polarized component of the GNSS signal and the second linearly polarized component of the GNSS signal to generate a circularly polarized GNSS signal; an n-plexer between the second linearly polarized antenna and the hybrid coupler, an n-plexer configured to separate the second linearly polarized component of the GNSS signal from the radio frequency signal compliant with the second wireless communication technology and to send the second linearly polarized component of the GNSS signal to the hybrid coupler; 1. A GNSS receiver comprising:

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