Antenna systems for obtaining position information using polarization loss optimization

Abstract

Systems and methods are provided for tuning network devices, such as access points (APs). Examples include receiving a circularly polarized signal by an antenna of an access point and obtaining a first linearly polarized component and a second linearly polarized component of the circularly polarized signal. Examples also include identifying a signal with the greatest signal power based on a comparison of the first and second linearly polarized components, obtaining geographic coordinates for the access points from the identified signal, and connecting to a network based on the obtained geographic coordinates.

Description

background

[0001] Determining reliable, accurate locations of access points (APs) or other network devices can be useful for many applications, such as providing network services and locating other devices on the network, such as client devices. Techniques for locating network devices include measuring radio signals emitted by a variety of devices or facilities, including satellites. For example, modern electronic devices have systems that can receive signals from satellite navigation systems, commonly referred to as global navigation satellite systems (each "GNSS"), which use satellite signals to determine the device's location. GNSS receivers can be integrated into network devices, such as APs or similar devices.Signals from multiple satellites orbiting the Earth can be received and processed by the integrated GNSS receiver to determine the location of the GNSS receiver and, by proxy, the location of the network device. Brief description of the drawings

[0002] The present disclosure will be described in detail in accordance with one or more various embodiments with reference to the following figures. The figures are for illustrative purposes only and represent only typical or exemplary embodiments. The Fig. show an example of a network configuration that may be implemented in accordance with the present disclosure. Fig. shows the rotation of an electric field vector of a circularly polarized electrical signal, which may be an example of a positioning signal according to the present disclosure. Fig. is a schematic block diagram of an example receiver according to the teachings of the present disclosure. Fig. shows an example of a computer component that may be used to tune a network device in accordance with various implementations of the present disclosure. Fig. is a schematic block diagram of another example of a receiver according to the teachings of the present disclosure. Fig. is a flowchart of an example calibration process according to an example implementation. Fig. is a schematic block diagram of another example of a receiver in accordance with the teachings of the present disclosure. Fig. is a flowchart of another example of a calibration process according to a sample implementation. Fig. is a schematic block diagram of another example of a receiver according to the teachings of the present disclosure. Fig. is a flowchart of another example of a calibration process according to a sample implementation. Fig. is an example of a computer system that may be used to implement various features of the polarization loss optimization calibration according to the present disclosure.

[0003] The figures are not exhaustive and do not limit the present disclosure to the precise form disclosed. Detailed description

[0004] Implementations of the present disclosure generally relate to GNSS receivers integrated into network devices capable of detecting multiple linear components of circularly polarized signals to obtain a location of the GNSS receivers. In various examples, the disclosed implementations may be integrated into a network device, such as an AP or other device connected to a network, located in an indoor environment or other environment where line-of-sight propagation with the satellite is not possible (or unlikely). Line-of-sight (LoS) propagation refers to the properties of electromagnetic radiation whereby two devices transmit and / or receive signals when they are within direct line of sight of each other with no obstructions between them.The term “obstructed environment” as used here refers to an environment in which LoS propagation is not possible due to obstructions, such as indoor structures or other obstacles that may be located between two devices, indoors or outdoors.

[0005] The implementations disclosed herein can detect multiple linear components of circularly polarized signals to determine a rotation direction (sometimes referred to herein as "handedness") of the circularly polarized signals. The rotation direction can be used by the disclosed implementations to identify an optimal signal for obtaining a position of the GNSS receivers.

[0006] As described above, GNSS, such as the Global Positioning System (GPS) in the United States or similar, can be used by network devices to obtain location information about themselves and / or other network devices. A GNSS receiver can detect a GNSS signal encoded with location information and decode the detected GNSS signal to obtain location information encoded therein. The location information can be provided in the form of carrier frequency information, satellite identifiers, and navigation data (e.g., satellite orbit data, satellite clock data, satellite status information), which can be used to determine the location or geographic coordinates of the GNSS receiver.

[0007] As previously mentioned, GNSS receivers can be integrated into network devices, such as access points and the like, to obtain location information of the network device as well as the surrounding network devices connected to it. Each network device can have a built-in GNSS receiver to enable location anchoring. In some cases, a network's network devices may be deployed indoors, for example, behind walls, around corners, on ceilings, or other structures. This deployment may impede LoS propagation or otherwise affect LoS propagation between the GNSS receivers on the network devices and the GNSS satellites. In general, a network device located near a window or otherwise having an unobstructed LoS connection to the satellite may be able to obtain more accurate location information compared to other network devices that do not have a LoS connection to GNSS satellites.In this case, the network device closer to the window (called an anchor network device) can detect GNSS signals and obtain its location information, which can be used to determine the locations of the other APs. For example, the anchor network device can perform Fine Timing Measurement (FTM) measurements and synthesize data to automatically locate other devices in the network (such as other APs and connected client devices). For example, each AP has a corresponding GNSS receiver that performs FTM measurements with neighboring APs to locate itself relative to the neighboring APs. Its location can be synchronized with the connected devices to locate these connected devices based on the FTM measurements.

[0008] In another example, network devices can use GNSS signals to obtain location information for providing network services to other connected devices, such as client devices. For example, a network device implemented as an AP may be required to determine its geographic location using GNSS and report the location for the provision of frequency bands for use by the AP. For example, the Federal Communications Commission (FCC) defines Unlicensed National Information Infrastructure (U-NII) areas of radio frequency spectrum available for use by network devices. The U-NII consists of two bands: U-NII 1 through 4 are for the 5 GHz frequency bands, and U-NII 5-8 are for the 6 GHz frequency band.For U-NII 5 and 7, FCC regulations may require automatic frequency coordination (AFC), in which an AP locates itself and reports the location, along with an FCC identifier (FCCID), a serial number, and other vendor-specific elements (VSE) associated with the AP, to an AFC database. An AFC service can then assign the AP a frequency band and the AP's allowable transmit power to avoid interference with established devices on the network. The AP can then use the allocated frequency band to provide services on the network.

[0009] GNSS signals transmitted by GNSS satellites typically use right-hand circular polarization (RHCP) to transmit signals to Earth. GNSS signals also tend to have relatively small amplitudes due to propagation losses as the GNSS signals traverse the atmospheric path to network devices on Earth. Therefore, GNSS receivers typically must be able to receive RHCP signals with sufficient passive amplification, a low axial ratio between the orthogonally polarized components of the RHCP, and minimal loss due to polarization mismatch. In addition, GNSS receivers generally incorporate low-noise amplifiers (LNAs) that amplify a received GNSS signal to amplify the signal. This includes amplifying any noise floor imposed on the GNSS signal due to the GNSS receiver's traversal.For a GNSS receiver, every decibel of sensitivity improvement can have a significant impact on the accurate acquisition of a GNSS signal and the preservation of the location information encoded within it. Furthermore, increasing the passive gain of the transmitted GNSS signal can have an improved effect on the sensitivity of the GNSS receiver, as passive gain can serve to amplify the GNSS signal transmitted by the satellite without increasing the noise floor at the GNSS receiver. This means that a component of the received GNSS signal encoded with the location information can be amplified without also amplifying a noise component of the GNSS signal.

[0010] Furthermore, in environments with obstructions, GNSS signals can be reflected off structures or other obstacles on their way to the GNSS receiver. However, the polarization of a GNSS signal can change from RHCP to left-handed circular polarization (LHCP) or vice versa with each reflection. The extent of the change in rotation direction can depend on an angle of reflection or incidence, so a reflected GNSS signal can assume eccentricities between LHCP and RHCP. Therefore, a GNSS receiver can receive GNSS signals that are RHCP when the GNSS signals are not reflected or when the GNSS signals are reflected an even number of times, or it can receive GNSS signals that are LHCP when the signals are reflected an odd number of times.As a result, receiving a direct RHCP GNSS signal can be nearly impossible in obstructed environments, and GNSS receivers must rely on reflected GNSS signals. For example, an indoor AP may rely on GNSS signals coming through windows or similar open spaces, which are reflected one or more times before reaching the AP. Furthermore, the GNSS signal is attenuated with each reflection, so the signal power decreases after each reflection.

[0011] In some cases, reflected GNSS signals can become elliptical polarization signals or signals with other polarization states. Therefore, the term "GNSS signal" used here refers to any radio-frequency signal compliant with GNSS technology that has a nonlinear polarization state that rotates left or right, including circular polarization, elliptical polarization, or unpolarized polarization. This allows GNSS receivers in a hidden environment to receive GNSS signals transmitted from the same satellite with different polarization states.

[0012] To solve the above technical problems, some GNSS receivers use a linearly polarized antenna connected in series with an LNA. Examples of linearly polarized antennas include a planar inverted-F antenna (PIFA), wire antennas (e.g., dipoles, monopoles, etc.), loop antennas, antenna arrays, patch antennas, slot antennas, aperture antennas (e.g., horns, waveguides, etc.), and the like. These linearly polarized antennas can receive a linearly polarized component of a GNSS signal for use in positioning. For example, a linearly polarized antenna can be configured to receive a vertically polarized component of a circularly polarized GNSS signal. Furthermore, a linearly polarized antenna can receive a linearly polarized component of a GNSS signal regardless of the polarization rotation direction and can thus receive both RHCP and LHCP signals.Consequently, a linearly polarized antenna can accommodate unknown polarization states caused by reflections. However, a linearly polarized antenna may experience signal power loss due to polarization mismatches. In the case of a RHCP or LHCP GNSS signal, for example, up to half of the signal power (e.g., up to 3 dB loss) can be lost at the linearly polarized antenna before reaching the LNA. The amount of power loss can vary depending on the polarization state of the received GNSS signal (e.g., circular polarization versus elliptical).

[0013] While RHCP antennas can receive RHCP GNSS signals more efficiently and with low losses due to polarization mismatch, RHCP GNSS antennas may not be able to receive LHCP GNSS signals due to polarization mismatch. Furthermore, signal power decreases with each reflection, so after two reflections, there may not be enough signal power to distinguish the location information encoded in the GNSS signal from the background noise. For this reason, RHCP antennas cannot adequately address the technical problems described above in environments with obstacles. For example, RHCP antennas are only as good as the direction they are pointing relative to a satellite. Thus, RHCP antennas can be most efficient when pointed upwards, toward the satellite.However, in many indoor environments, antennas are ceiling-mounted, which can cause the antenna to point downward toward the floor. Therefore, ceiling-mounted antennas may rely on cross-directional or reflected GNSS signals, and RHCP antennas may lose efficiency in these configurations.

[0014] Accordingly, the implementations disclosed herein provide a network device including a receiver, such as a GNSS receiver, configured to detect a plurality of linearly polarized components of a received circularly polarized signal. As a result, the disclosed implementations enable reception of GNSS signals with increased signal power compared to a single linearly polarized component. In various examples, the network device may be an AP configured to obtain location information of the AP from a GNSS signal received in accordance with the examples disclosed herein. In some examples, the AP may be configured to connect to a network based on the obtained location information.In other examples, the AP may be configured to determine the location of other network devices in a network based on the received GNSS signal.

[0015] In various examples, a receiver includes a dual-polarized antenna configured to detect two linearly polarized components of a GNSS signal. For example, the dual-polarized antenna may detect a first linearly polarized component and a second linearly polarized component of the circularly polarized signal. The linearly polarized components may be orthogonally polarized relative to each other (e.g., vertical and horizontal components). Thus, the disclosed implementations may detect two linearly polarized components of GNSS signals regardless of the polarization rotation direction.

[0016] The network devices of the present disclosure may include a controller (e.g., a processor or other computing component). The controller may be configured to identify a signal with the greatest signal power based on a comparison of the first and second linearly polarized components. The controller may be configured to calibrate the receiver based on the identified signal. The receiver may be configured to demodulate the identified signal to obtain location information encoded therein (e.g., carrier frequency information, satellite identifiers, and navigation data—such as satellite orbit data, satellite clock data, and information about the state of the satellite that may be used to determine location or geographic coordinates).

[0017] The controller may use various methods to identify a signal based on a comparison of the first and second linearly polarized components. For example, the controller may be configured to compare the amplitudes of the first and second linearly polarized components to determine which linearly polarized signal has the greatest signal power. The controller may then calibrate the receiver to use the identified linearly polarized signal, which may be used to determine geographic coordinates. For example, the controller may calibrate the receiver to amplify a signal received from a specific satellite. The receiver may then be operated to receive signals from multiple satellites simultaneously and combine the signals received at different times to obtain geographic coordinates.

[0018] In another example, the controller may identify a signal based on applying a phase delay to a linearly polarized component. For example, the controller may be configured to iteratively apply a plurality of phase delays to the first linearly polarized component. For each phase delay, the phase-delayed first linearly polarized component may be combined with the second linearly polarized component to generate a combined signal. The controller may then determine a signal power of each combined signal and identify a combined signal with the greatest signal power. The controller may then calibrate the receiver to use the identified combined signal.

[0019] In another example, the controller may identify a signal based on the combination of the linearly polarized components to generate a combined circularly polarized signal. For example, the first and second linearly polarized components may be input to the first and second inputs of a switch (e.g., a diamond switch known in the art). The outputs of the switch may be combined to generate a first combined circularly polarized signal. The inputs may then be switched to output a second combined circularly polarized signal. The signal strengths of the first and second combined circularly polarized signals may be compared to determine which signal is greater. The controller may then calibrate the receiver to use the combined circularly polarized signal with the greatest signal power.

[0020] It should be noted that the terms "optimize," "optimal," and the like, as used herein, may be used to make or achieve performance as effective or perfect as possible. However, as one skilled in the art reading this document will recognize, perfection cannot always be achieved. Accordingly, these terms may also mean making or achieving performance as good or effective as possible or practical under the circumstances, or making or achieving performance better than that achievable with other settings or parameters.

[0021] Before describing examples of the disclosed systems and methods in detail, it is useful to describe an example network installation (also called a deployment) with which the disclosed systems and methods could be implemented in various applications. Fig. show an example of a network configuration 100 that may be implemented for an organization, such as a business, an educational institution, a government agency, a healthcare facility, or other organization. The organization of the network configuration 100 may include multiple users (or at least multiple client devices 110) and possibly multiple physical or geographic locations, such as the primary site 102, the remote site 132, and the remote site 142. The network configuration 100 may include a primary site 102 that communicates with a network 120. The network configuration 100 may also include one or more remote sites 132, 142 that communicate with the network 120. The network 120 may enable each geographic location of the network configuration 100 of an organization to communicate with each other.

[0022] The primary site 102 may include a primary network, which may be, for example, an office network, a home network, or other network installation. The network of the primary site 102 may be a private network, such as a network that may include security and access controls to restrict access to authorized users of the private network. Authorized users may include, for example, employees of a company at the primary site 102, residents of a home, customers of a company, etc.

[0023] In the illustrated example, primary site 102 includes a network controller 104 that communicates with network 120. Network controller 104 may provide communication with network 120 for primary site 102, although network controller 104 need not be the sole point of communication with network 120 for primary site 102. A single network controller 104 is illustrated, although primary site 102 may include multiple controllers and / or multiple points of communication with network 120. In some examples, network controller 104 communicates with network 120 via a router (not shown). In other examples, network controller 104 provides router functionality to devices, such as client devices 110, at primary site 102.

[0024] A network controller 104 may configure and manage network devices, e.g., at the main site 102, and may also manage network devices, e.g., gateway device 134, access points (APs) 136, switch 138, gateway device 144, and AP 146, at the remote sites 132, 142. The network controller 104 may configure and / or manage switches, routers, access points, and / or client devices connected to a network. The network controller 104 may itself be an access point or provide the functionality of one.

[0025] Network controller 104 may communicate with one or more switches 108 and / or wireless APs 106A-C. Switches 108 and wireless APs 106A-C may provide network connectivity to various client devices 110A-J. Through a connection to a switch 108 or AP 106A-C, a client device of the client devices 110A-J may access network resources, including other devices on the primary site network 102 and on the network 120.

[0026] Examples of client devices may include: desktop computers, laptops, servers, web servers, authentication servers, authentication-authorization-accounting (AAA) servers, Domain Name System (DNS) servers, Dynamic Host Configuration Protocol (DHCP) servers, Internet Protocol (IP) servers, virtual private network (VPN) servers, network policy servers, mainframe computers, tablet computers, e-readers, netbook computers, televisions and similar displays (e.g., smart TVs), content receivers, set-top boxes, personal digital assistants (PDAs), mobile phones, smartphones, smart terminals, silent terminals, virtual terminals, video game consoles, virtual assistants, Internet of Things (IOT) devices, and the like. Client providers may connect to an organization's primary site network 102, remote site network 132, and / or remote site network 142 using client devices, such as:Client devices 110A-J, client devices 140A-D and / or client devices 150A-B.

[0027] Within primary site 102, a switch 108 is included as an example of an access point to the network established at primary site 102 for wired client devices 1101-J. Client devices 1101 and 110J can connect to switch 108 and access other devices within network configuration 100 through switch 108. Client devices 1101 and 110J can also access network 120 through switch 108. Client devices 1101 and 110J can communicate with switch 108 via a wired connection 112. In the illustrated example, switch 108 communicates with network controller 104 via a wired connection 112, although this connection may also be wireless.

[0028] Wireless APs 106A-C are another example of an access point to the network established at primary site 102 for client devices 110A-H. Each of APs 106A-C may be a combination of hardware, software, and / or firmware configured to provide wireless network connectivity to wireless client devices 110A-H. In the example shown, APs 106A-C may be managed and configured by network controller 104. APs 106A-C may communicate with network controller 104 and the network of primary site 102 via connections 112, which may be either wired or wireless interfaces.

[0029] The network configuration 100 may include one or more remote locations, such as the remote location 132. The remote location 132 may be located in a different physical or geographic location than the primary location 102. In some cases, the remote location 132 may be located in the same geographic location or possibly in the same building as the primary location 102, but may not have a direct connection to the network of the primary location 102. Instead, the remote location 132 may utilize a connection through another network, such as the network 120, to connect to the network of the primary location 102. For example, the remote location 132 may be a satellite office, a different floor or suite in a building, etc. The remote location 132 may include a gateway device 134 for communicating with the network 120.A gateway device 134 may be a router, a digital-to-analog modem, a cable modem, a DSL modem, or other network device configured to communicate with the network 120. The remote site 132 may also include a switch 138 and / or an AP 136 that communicates with the gateway device 134 via either wired or wireless connections. The switch 138 and AP 136 may provide network connectivity for various client devices 140A-D.

[0030] In various examples, the remote site 132 may be in direct communication with the primary site 102 such that the client devices 140A-D at the remote site 132 access the network resources at the primary site 102 as if the client devices 140A-D were located at the primary site 102. In such examples, the remote site 132 may be managed by the network controller 104 at the primary site 102, and the network controller 104 may provide the necessary connectivity, security, and accessibility enabling the remote site 132 to communicate with the primary site 102. Once connected to the primary site 102, the remote site 132 may function as part of a private network provided by the primary site 102.

[0031] In various examples, the network configuration 100 may include one or more smaller remote sites, such as the remote site 142, which includes only a gateway device 144 for communicating with the network 120 and a wireless AP 146 through which various client devices 150A-B can access the network 120. Such a remote site 142 may, for example, be the home of an individual employee or a temporary remote office. The remote site 142 may also communicate with the primary site 102 so that the client devices 150A-B at the remote site 142 access network resources at the primary site 102 as if those client devices 150A-B were located at the primary site 102. The remote site 142 may be managed by the network controller 104 at the primary site 102 to enable this transparency.Once connected to the main site 102, the remote site 142 may function as part of a private network provided by the main site 102.

[0032] The network 120 may be a public or private network, such as the Internet or another communications network, to enable the connection between the various locations 102, 132, and 142, as well as access to servers such as servers 160A-B. The servers 160A-B may also be remote computing devices and / or nodes that may be executed to perform the functions disclosed herein. Thus, the implementation disclosed herein may be executed directly on the APs 106A-C, on the servers 160A and / or 160B, or distributed across the AP and servers in a post-processing manner. The network 120 may include third-party telecommunications lines, such as telephone lines, broadcast coaxial cables, fiber optic cables, satellite communications, cellular communications, and the like. The network 120 may include any number of intermediate network devices, such asSwitches, routers, gateways, servers, and / or controllers that are not directly part of the network configuration 100, but facilitate communication between the various parts of the network configuration 100 and between the network configuration 100 and other devices connected to the network. The network 120 may include various content servers, such as servers 160A-B. The servers 160A-B may be various providers of downloadable multimedia and / or streaming content, including audio, video, graphics, and / or text content, or any combination thereof. For example, the servers 160A-B may include web servers, streaming radio and video providers, and cable and satellite television providers. The client devices 110A-J, 140A-D, 150A-B may request and access the multimedia content provided by the servers 160A-B over the network 120.

[0033] Although in the example of Fig. While ten client devices 110A-J are shown at the main site 102, a network in various applications may include fewer or greater numbers of client devices. Indeed, some implementations may include a significantly larger number of client devices. For example, various wireless networks may include hundreds, thousands, or even tens of thousands of clients communicating with their respective APs, possibly even at the same time.

[0034] The network configuration 100 may include a positioning system 170 configured to provide location information of the Fig. shown network devices. As in the example of Fig. For example, as shown, AP 106A includes a receiver 118 that can receive positioning signals from positioning system 170, which can be used by receiver 118 to determine the location of receiver 118 and thus also of AP 106A. While in Fig. a single receiver is shown, other receivers can be configured in a similar way in the other network devices of Fig. , such as other APs 106B-106C, switch 108, etc. Location information may be provided as the latitude and longitude, and possibly the altitude of the receiver (e.g., receiver 118). The location information may also be specified as the relative location of the receiver, such as distances north or south, east or west, and possibly above or below other known fixed locations. A location may also be specified as a geodetic location (as latitude and longitude), a civic location (e.g., in the form of a street address or using other location-related names and labels), a local location (e.g., in terms of distances to known structures or objects in an environment, such as a building with an interior environment consisting of walls, ceilings, etc.).

[0035] Positioning system 170 may include one or more satellites, such as satellites 172A-172C (collectively referred to as satellites 172 or individually as satellite 172). Each satellite 172A-172C may transmit a corresponding position signal 174A-174C to network devices. Position signals 174A-174C may each include location information 176A-176C. A receiver, such as receiver 118, may acquire position signals 174A-174C, receive location information 176A-176C encoded thereon, and estimate the receiver's location based on the received location information 176A-176C. For example, receiver 118 may receive positioning signals 174A-174C and demodulate each positioning signal 174A-174C to obtain location information 176A-176C. Location information 174A-174C may include, among other things, information that can be used to resolve the geographic coordinates of receiver 118.For example, each signal 174A-174C may include carrier frequency information, a satellite identifier, and navigation data (e.g., satellite orbit data, satellite clock information, satellite status information) that may be used to determine the location or geographic coordinates of the receiver 118. Based on the location information, the receiver 118 may determine (e.g., estimate) its current geographic location. For example, the location information 174A-174C obtained from multiple satellites 172 may be used to determine the geographic coordinates of the receiver 118.

[0036] In the example of Fig. Three satellites are shown for illustrative purposes. However, the positioning system 170 may include any number of satellites 172. For example, the positioning system 170 may include a constellation of satellites 172 in synchronized orbits to transmit electromagnetic signals (e.g., positioning signals 174A-174C) to locations across a large portion of the Earth's surface simultaneously from multiple satellites in the constellation. A satellite belonging to a particular positioning system may transmit positioning signals in a format unique to that particular positioning system. A receiver (e.g., receiver 118) may be used to determine the absolute location as well as the relative location of a network device in which the receiver is installed. For example, the satellites 172 may transmit positioning signals 174A-174C that may be received by the receiver 118.Receiver 118 can determine the absolute position of AP 106A by processing position signals 174A-174C. Satellites 172A-172C can orbit at an altitude of, for example, approximately 20,000 km to approximately 23,000 km and can have known time and ephemeris. Satellites 172A-172C can transmit position signals 174A-174C containing pseudorandom patterns. Position signals 174A-174C can contain L-band carrier frequencies, such as 1575.42 MHz (L1), 1227.6 MHz (L2), or 1176.45 MHz (L5), modulated at approximately 1 MHz and / or approximately 10 MHz. Since the satellites are constantly moving, the receiver 118 can continuously acquire and track the position signals 174A-174C from the satellites 172. The receiver 118 can demodulate the received positioning signals 174A-174C to obtain the location information 174A-174C and determine its distance from a number of satellites based on the speed of the electromagnetic wave (e.g.,speed of light) and the travel time (e.g., time of flight) of the incoming signals moving through space, which can be determined using the local clocks of the satellites and the receiver.

[0037] In various examples, the positioning system 170 may be a GNSS, and the satellites 172 may be GNSS satellites. GNSS satellites may be, for example, but not exclusively, satellites for the Global Position System (GPS, USA), Galileo (European Union), Glonass (Russia), Beidou (China), or the like. In these examples, the satellites 172 may transmit positioning signals 174A-174C as GNSS signals, which typically have RHCP polarization. The receiver 118, as well as other receivers included in the network devices of Fig. can be GNSS receivers. For example, receiver 118 implemented as a GNSS receiver can receive GNSS signals from satellites 172A-172C. Based on the GNSS signals, receiver 118 can determine the absolute position of AP 106A by demodulating the received signals 174A-174C to obtain location information 176A-176C.

[0038] While the examples described herein refer to APs 106 receiving location information from a positioning system 170, the present disclosure is not intended to be limited to this implementation alone. APs 106 are presented as an illustrative example, and other network devices may be implemented to receive position signals from satellites of the positioning system 170. For example, switch 108, switch 138, AP 136, gateway device 144, etc., may each include a receiver, such as receiver 118, for receiving location signals and estimating the location of a corresponding network device.

[0039] The network devices may be configured to use the received location information to provide services and functions of the respective network device. For example, APs 106A-106C may detect positioning signals and obtain their respective location information, which may be used to determine the locations of other APs or network devices in network 120. In one illustrative example, receiver 118 of AP 106A may receive and detect positioning signals 174A-174C and estimate its position based on the location information 176A-176C contained therein. AP 106A may be considered an anchor AP that may use its location to determine the locations of other network devices in network 120, such as, but not limited to, other APs, switches, client devices, etc.AP 106A can perform Fine Timing Measurement (FTM) measurements and synthesize data based on the FTM measurements to locate other network devices and estimate their positions.

[0040] Another example is that network devices, such as APs 106A-106C, may use their respective location information to provide network services to connected network devices, such as client devices 110A-110J. For example, APs 106A-106C may be required to locate themselves by estimating their geographic location and reporting the location for the purpose of providing frequency bands for use by APs 106A-106C. The FCC defines U-NII radio frequency bands of the radio frequency spectrum available for use by network devices such as APs 106A-106C. The U-NII consists of two ranges: U-NII 1 through 4 are for the 5 GHz frequency bands, and U-NII 5-8 are for the 6 GHz frequency band. U-NII 5 and 7 may require AFC according to FCC regulations.As part of AFC, APs 106A-106C can be required to determine a geographic location and self-report this location, along with an FCCID, a serial number, and other VSEs associated with the respective AP, to an AFC database. An AFC service can then report back to APs 106A-106C a specific frequency band and the power levels allowed for each AP 106A-106C to avoid interference with established devices in the network. APs 106A-106C can then provide network services to other network devices using the provided frequency band.

[0041] As already mentioned, positioning signals, such as GNSS signals, typically propagate with circular polarization. Fig. shows the rotation of an electric field vector of a circularly polarized electrical signal 200, which may be an example of a position signal (e.g., position signals 174A-174C). In this example, the circularly polarized electrical signal 200 propagates in the +Z direction. The circularly polarized electrical signal 200 may include a first component 202 in which the electric field oscillates in a first plane (e.g., a vertical plane, represented in this example as the YZ plane) and a second component 204 in which the electric field oscillates in a second plane orthogonal to the first plane (e.g., the XZ plane in this example). Thus, the first component 202 and the second component 204 may both be linearly polarized and synchronized with each other.Depending on the phase and / or amplitude difference between the first component 202 and the second component 204, the combined electric wave can be linearly polarized, circularly polarized, or elliptically polarized. For example, if the phases of the first component 202 and the second component 204 are the same, the combined electric wave can be a linearly polarized wave with the electric field vector pointing in the same direction. If the amplitudes are different, the combined electric wave can be elliptically polarized, for example.

[0042] In circular polarization signals, an electric field of the two orthogonal vector components 202 and 204 may not peak simultaneously, but rather offset by 90° (e.g., 1 / 4 wavelength) from each other. Instead, the resulting combined vector of the two components 202 and 204 may rotate 360° per wavelength during propagation, represented as a circularly polarized electrical signal 200. The direction or handedness (e.g., right- or left-handed) of the circular rotation may depend on whether the first component 202 or the second component 204 peaks first. For example, if the second component 204 peaks first, followed by the first component 202, the electromagnetic wave may be RHCP. If the first component 202 peaks first relative to the second component 204, the electromagnetic wave may be LHCP.

[0043] Circularly polarized signals can be more tolerant of physical misalignment between the transmitting antenna (e.g., on the satellite) and a receiving antenna at the receiver. For example, if a satellite transmits a signal with vertical polarization, a vertically oriented linear antenna can receive a strong signal, but if the receiving antenna is oriented at an angle relative to the vertical, the received signal strength can be reduced (e.g., the received signal strength can be reduced by more than 20 dB if the antenna is oriented horizontally). Conversely, if a satellite transmits a circularly polarized signal, a receiver with a linear antenna can receive the signal regardless of whether the linear antenna is oriented vertically or horizontally, but only the component of the circularly polarized signal that is aligned with the linear orientation of the receiving antenna.

[0044] In obscured environments, reflections may be unavoidable, as signals bounce off surrounding surfaces. Some receivers may not have a LoS with a satellite and can therefore only receive reflected signals. The direction of circular rotation may change due to reflections, so an RHCP electromagnetic wave may transform into an LHCP wave upon reflection from a structure or object. In other cases, the direction of circular rotation may change due to reflections, reversing the direction of rotation received by a receiver.

[0045] For example, network devices may be deployed in a restricted environment, the boundaries of which are clearly shown as location 102 (see Fig. ). As an illustrative example, the location 102 may be an indoor space, such as an office, facility, or other physical structure (e.g., a building) with an opening 116 (e.g., a window or door) to the outside environment. In this example, the AP 106A may be positioned near the opening 116, allowing unobstructed LoS propagation with the satellites 172, as shown in Fig. shown. However, AP 106B, AP 106C, and switch 108 may be placed elsewhere in the obstructed environment at a distance from opening 116, resulting in obstructed LoS propagation. For example, AP 106B may be placed against a wall around a corner, so that another wall lies between AP 106B and satellites 172. In another example, AP 106B and / or AP 106C may be mounted on the ceiling with the antenna pointing downward toward the floor (as in Fig. shown).

[0046] An obstruction of LoS propagation between receivers located on the network devices of Fig. installed, and satellites, such as satellite 172, may negatively impact the ability of receivers to receive positioning signals (e.g., positioning signals 174A-174C) and obtain the location information encoded therein. Positioning signals, such as those transmitted by satellites 172, generally use RHCP, and in obstructed environments, positioning signals may be reflected before reaching a receiver, resulting in a switch from RHCP to LHCP or vice versa. As a result, reception of a direct RHCP position signal may be nearly impossible in this environment.

[0047] As in Fig. 1B, the APs 106C and 106B, for example, must rely on positioning signals that come through the opening 116 and may be reflected one or more times before reaching the respective AP. In the illustrative example of Fig. AP 106B is positioned on a ceiling 105 of a room 107 of primary site 102, and AP 106C is positioned on a ceiling 101 of room 109. The antennas of APs 106B and 106C may be directed toward the floor. In this case, AP 106B may, for example, receive position signal 174D as a direct LoS transliteration, where position signal 174D has a nearly linear polarization. Alternatively, or in combination with position signal 174D, AP 106B may receive position signal 174E entering through opening 116 and reflecting off the floor before being received by AP 106B. AP 106C may similarly receive a reflected position signal 174G. These reflected signals may be a skewed LHCP. As another example, position signal 174F may be scattered upon impact with the ground. Scattered signals may be linearly polarized. AP 106B may also receive a direct vertical reception, which is RHCP, such asthe position signal 174H; however, this signal is attenuated due to its passage through the ceiling 105. Therefore, receiving a direct RHCP position signal with sufficient signal strength to obtain location information encoded therein may be virtually impossible in this environment.

[0048] While circularly polarized antennas can be implemented in APs 106A-106B to efficiently receive circularly polarized electronic signals, the antennas may need to be aligned according to the rotation direction of the circular polarization. Otherwise, the antennas may not be able to receive the transmitted position signal due to a mismatch in the polarization orientation. Furthermore, the signal strength / power (e.g., amplitude) may decrease with each reflection, so that after two reflections, a signal may no longer have sufficient signal power for a receiver to distinguish between the information encoded in the signal and the background noise.

[0049] Thus, linearly polarized antennas, such as patch antennas, inverted-F antennas (IFAs), PIFAs, wire antennas, loop antennas, antenna arrays, patch antennas, slot antennas, aperture antennas, etc., can be used in receivers for detecting circularly polarized electromagnetic signals on network devices of Fig. 1. As already mentioned, a linearly polarized antenna can receive RHCP, LHCP, elliptically polarized and / or linearly polarized signals. Especially in obstructed environments (e.g., as in the example of site 102 of Fig. described), linearly polarized antennas can be useful for receiving RHCP signals via LoS propagation, as well as LHCP signals due to reflections. However, a linearly polarized antenna with a single polarization can only detect one component of a circularly polarized signal (e.g., one of the first component 202 or the second component 204, depending on the orientation of the linearly polarized antenna). Therefore, the signal level received by a linearly polarized antenna can decrease by up to 3 dB (e.g., half the power of the circularly polarized signal).

[0050] Accordingly, examples of the present disclosure provide receivers that include an antenna configured to detect (e.g., detect) a plurality of linearly polarized components of a received circularly polarized electromagnetic signal. For example, receiver 118 may include an antenna capable of detecting a plurality of linearly polarized components of positioning signals 174. Such antennas may be referred to herein as multipolarized antennas. In some examples, a multipolarized antenna may be implemented as a dual-polarized antenna configured to detect two linear components of a circularly polarized electromagnetic signal (e.g., vertical and horizontal components).

[0051] With reference to Fig. For example, AP 106B and AP 106C may include receivers (e.g., receiver 118) capable of detecting a plurality of linearly polarized components. In the case of positioning signal 174E (e.g., translational reception), a component of linearly polarized positioning signal 174E may be aligned (e.g., tuned) to one or more of the polarizations of the antenna of AP 106C. A similar situation may occur for scattered position signal 174F. In the case of reflected positioning signals 174D and 174G that are skewed LHCP, the LHCP will be eccentric to the linear components of the antennas, allowing one or more components of reflected positioning signals 174D and 174G to be detected.

[0052] Fig. is a schematic block diagram of an example of a receiver 300 according to implementations of the present disclosure. The receiver 300 may be implemented in network devices such as the APs 106A-106C or other network devices of Fig. included (e.g., installed, embedded, or otherwise attached thereto) and configured to receive position signals such as 174A-174C. In an example implementation, receiver 300 may be a GNSS receiver capable of receiving GNSS signals and extracting location information from the incoming signal. As described above, a GNSS receiver may be configured to estimate a geographic position of the GNSS receiver based on the location information extracted from the GNSS signal, which may be extended to the network device in which the GNSS receiver is embedded.

[0053] Receiver 300 may include an antenna 310, a radio frequency (RF) front-end 320, and a processing module 330. RF front-end 320 and processing module 330 may each include various modules that may be implemented in hardware, software, or combinations thereof.

[0054] The antenna 310 can be configured to receive circularly polarized signals such as those transmitted by the satellites 172 in Fig. transmitted. The antenna 310 may be configured to receive signals in various frequency bands, polarizations, and elevation angles. The antenna 310 may be implemented as a multipolarized antenna configured to receive a circularly polarized signal (e.g., RHCP and / or LHCP signal) and detect a plurality of linearly polarized components of the circularly polarized signal. For example, the antenna 310 may be a dual-polarized antenna configured to detect a first component and a second component of a circularly polarized signal. For example, the antenna 310 may include a first linear component 318 oriented in a first direction and a second linear component 316 oriented in a second direction.The first linear component 318 may be oriented to detect the first component of the circularly polarized signal, while the second linear component 316 may be oriented to detect the second component of the circularly polarized signal. In one illustrative example, the first component may be a vertical component and the second component may be a horizontal component. Thus, in this example, the first linear component 318 may be a vertically oriented component of the antenna 310, and the second linear component 316 may be a horizontally oriented component of the antenna 310. In some examples, the antenna 310 may be implemented as a dual-polarized crossed dipole antenna, a dual-pin patch antenna, or other dual-polarized antenna as known in the art.

[0055] The antenna 310 may be electrically connected to the RF front end 320 via a plurality of component paths, each component path corresponding to a detected linearly polarized component of the circularly polarized signal. In the example of Fig. The receiver 300 includes a first component path 312 and a second component path 314, via which the first and second components of the signal detected by the antenna 310 can be transmitted to the RF front end 320. In the case of more than two components, additional component paths can be provided.

[0056] The RF front-end 320 may include a pre-filter section 322 and a pre-amplifier section 324. The pre-filter section 322 may include a plurality of filters 323 and 325 that may be configured to filter the signal received by the antenna 310 to remove signals outside the carrier frequency band associated with the antenna 310 (e.g., L-band), reduce the effects of aliasing, and limit the noise bandwidth. For example, the filter 323 may be connected to the first component path 312 and receive the first component of the circularly polarized signal. The filter 323 may be configured to filter the first component to remove signals outside the carrier frequency band of the antenna 310, reduce the effects of aliasing, and limit the noise bandwidth. Filter 325 may be connected to the second component path 314 and receive the second component of the circularly polarized signal.The filter 325 may be configured to filter the second component to remove signals outside the carrier frequency band of the antenna 310, reduce the effects of aliasing, and limit the noise bandwidth.

[0057] Preamplifier section 324 may generally include a plurality of low-noise amplifiers (LNAs) 327 and 329 configured to amplify the signals filtered by prefilter section 322 to increase the signal strength (also referred to as signal power) to a level suitable for downstream processing. For example, LNA 327 may receive a filtered first component from filter 323 and amplify the signal to a level suitable for processing. Similarly, LNA 329 may receive a filtered second component from filter 325 and amplify the signal to a level suitable for processing.

[0058] A suitable level for processing can refer to a signal level received from a satellite that is within the sensitivity range of the receiver to accurately decode the signal. The higher the signal level for a received signal, the more accurately the receiver can determine the location. To illustrate, an example: A minimum received signal at the antenna might be approximately -128.5 dBm for L1 signals and -127 dBm for L5 signals. After filtering and amplification, the nominal carrier-to-noise level is approximately 40-45 dB for L1 and 42-47 dB for L5.

[0059] The processing system 330 may, for example, include a controller 332 configured to execute a calibration module 334 and / or a position determination module 336. The control unit 332 may, for example, be a processor or other computer system (e.g., the computer system 1100 of Fig. ). The controller 332 may perform a calibration process at the calibration module 334 based on the first and second components of the circularly polarized signal output from the front end 320. For example, the controller 332 executes a calibration module 334 based on a comparison of the first and second components to identify a signal with the greatest signal power. Further details on exemplary calibration processes performed by the calibration module 334 are described below in connection with the Fig. described.

[0060] The controller 332 may also execute the positioning module 336 to determine a position of the receiver 300 based on the circularly polarized signal received from the antenna 310. For example, the positioning module 336 may execute a process to determine a position of the receiver 300 based on the signal identified during the calibration process. For example, the positioning module 336 may be executed to obtain location information from the identified signal that the receiver 300 can use to estimate its current position. In one example, the control unit 332 may execute a demodulator 338 to demodulate the identified signal and have the positioning module 336 decode the position information contained in the signal.The positioning module 336 may then estimate a position of the receiver 300 using the decoded position information, as described above.

[0061] Accordingly, receiver 300 may be able to determine its position regardless of the rotation direction of the circularly polarized signal because antenna 310 is capable of detecting multiple linear components. Thus, regardless of the rotation direction of a circularly polarized signal, antenna 310 can detect different components of the incoming signal and process the components separately to identify the optimal signal for position determination.

[0062] Fig. shows an example of a computer component that can be used to implement tuning (e.g., calibration) of a network device in accordance with various implementations of the present disclosure. Referring to Fig. For example, the computer component 400 may be a controller (e.g., network controller 104 of Fig. and / or controller 332 of Fig. ) or other similar computer component that can process data. The computer component 400 may be part of a network device such as is used in conjunction with Fig. described (e.g. an AP or other). In the example implementation of Fig. Computing component 400 includes a hardware processor 402 and a machine-readable storage medium 404. In some examples, computing component 400 need not include machine-readable storage medium 404 and may be communicatively coupled (e.g., via a wired or wireless connection) to machine-readable storage medium 404.

[0063] The hardware processor 402 may be one or more central processing units (CPUs), semiconductor-based microprocessors, and / or other hardware devices capable of retrieving and executing instructions stored in the machine-readable storage medium 404. The hardware processor 402 may retrieve, decode, and execute instructions, such as instructions 406-412, to control processes or operations for tuning a network device. Alternatively, or in addition to retrieving and executing instructions, the hardware processor 402 may include one or more electronic circuits comprising electronic components for performing the functionality of one or more instructions, such as a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or other electronic circuitry.

[0064] A machine-readable storage medium, such as machine-readable storage medium 404, may be any electronic, magnetic, optical, or other physical storage device that contains or stores executable instructions. For example, machine-readable storage medium 404 may be random access memory (RAM), non-volatile RAM (NVRAM), electrically erasable programmable read-only memory (EEPROM), a storage device, an optical disk, or the like. In some examples, machine-readable storage medium 404 may be a non-transitory storage medium, where the term "non-transitory" does not include the transitory transmission signals. As described in detail below, machine-readable storage medium 404 may be encoded with executable instructions, such as instructions 406-412.

[0065] The hardware processor 402 may execute the instruction 406 to receive a circularly polarized signal via an antenna. In various examples, the network device may include a receiver, such as the receiver 300 of Fig. As such, the antenna may be implemented as antenna 310. The circularly polarized signal may be a GNSS signal that is a RHCP GNSS signal.

[0066] The hardware processor 402 may execute instruction 408 to obtain a first linearly polarized component of the circularly polarized signal and a second linearly polarized component of the circularly polarized signal. The first linearly polarized component may be orthogonal to the second linearly polarized component; for example, the first linearly polarized component may be a vertically polarized component and the second linearly polarized component may be a horizontally polarized component, or vice versa. In some examples, the antenna may receive the circularly polarized signal and detect the first and second linearly polarized components thereof. For example, the antenna may be a dual-polarized antenna that detects the first and second linearly polarized components.

[0067] The hardware processor 402 may execute instruction 410 to identify a signal having the greatest signal power based on a comparison of the first and second linearly polarized components.

[0068] In some examples, hardware processor 402 may execute instruction 410 to determine a first signal power of the first linearly polarized component and a second signal power of the second linearly polarized component. The first and second signal powers may be compared to determine which is the largest, and the component with the largest signal may be considered the identified signal. Further details regarding this example are provided below in connection with the Fig. described.

[0069] In another example, the hardware processor 402 may execute instruction 410 to iteratively apply a plurality of phase delays to the first linearly polarized component. Then, for each phase delay of the plurality of phase delays, the phase-delayed first linearly polarized component may be combined with the second linearly polarized component to generate a combined signal, and a signal power of the combined signal may be determined (e.g., for each phase-delayed first linearly polarized component). From the determined signal power for each combined signal, the combined signal with the greatest signal power may be determined, which may be considered the identified signal. Further details regarding this example are provided below in connection with the Fig. described.

[0070] In another example, hardware processor 402 may execute instruction 410 to input the first linearly polarized component to a first input of a switch and the second linearly polarized component to a second input of the switch. The switch may output a first combined circularly polarized signal. The inputs may then be switched, e.g., by inputting the first linearly polarized component to the second input and the second linearly polarized component to the first input, such that the switch outputs a second combined circularly polarized signal. The first signal power of the first combined circularly polarized signal may be compared to that of the second combined circularly polarized signal to determine which is larger, and the larger signal may be considered the identified signal.Further details on this example are given below in connection with the . Fig. described.

[0071] The hardware processor 402 may execute instruction 412 to obtain geographic coordinates for the access points from the identified signal. For example, using the signal identified by instructions 410, the receiver may demodulate the identified signal and obtain the location information encoded therein, as described above in connection with Fig. From the location information, the receiver can estimate its geographic position by resolving geographic coordinates, which can be derived as the geographic coordinates of the network device.

[0072] As described above, the network device can take certain actions based on the received geographic coordinates. For example, the network device can determine locations for other devices in the network. Another example is that the network device can self-report its location to allocate U-NII frequency bands for use by the network device in providing network services.

[0073] In some examples, computing platform 400 may execute a subset of instructions 406-412. For example, computing platform 400 may include an AP and a remote server. In this case, the AP may execute instructions 406-410 and the server may execute instructions 412. In another example, the AP may execute instructions 406-412. In another example, machine-readable storage media 404 may be located in cloud-based storage that may be accessed at a later time to execute instructions 406-412 when resources become available. In another example, an AP may acquire signals at different times using different settings and then store the information for post-processing by a remote processor, which may be configured to stitch optimized settings after signal acquisition.

[0074] Fig. is a schematic block diagram of another example of a receiver 500 according to implementations of the present disclosure.

[0075] As described above, GNSS receivers may need to operate in different L-bands. Accordingly, the receiver 500 includes a plurality of sub-receivers 505a-505n (collectively referred to herein as sub-receiver 505), each corresponding to a different L-band (e.g., L1, L2, L5, etc.). In the illustrative example of Fig. the receiver 500 includes a first sub-receiver 505a configured to operate in a first L-band (e.g., the L1 band) and a second sub-receiver 505n configured to operate in a second L-band (e.g., the L5 band).

[0076] The first sub-receiver 505a can essentially provide the receiver 300 with Fig. except that the pre-filter section 522a may be configured to remove signals outside the L1 band. Thus, the antenna 510a, which receives circularly polarized signals received from a positioning system (e.g., the positioning system 170 of Fig. are substantially similar to antenna 310. Antenna 510a detects first and second components of the circularly polarized signals and transmits the components to front end 520a via first component path 512a and second component path 514a, respectively. Pre-filter section 522a includes filters 523a and 525a, which serve to filter the first and second components, as described above in connection with Fig. The filtered signals may be fed to the preamplifier section 524a, which includes LNAs 527a and 529a configured to amplify the respective filtered components. The amplified components are fed to a processing engine 530, which is substantially similar to the processing engine 330 described above.

[0077] The second sub-receiver 505n may be substantially similar to the sub-receiver 505a, except that the pre-filter section 522n may be configured to remove signals outside the L5 band. Thus, the antenna 510n, which receives circularly polarized signals received from a positioning system (e.g., the positioning system 170 of Fig. be substantially similar to antenna 510a. Antenna 510n detects first and second components of the circularly polarized signals and transmits the components to front end 520n via first component path 512n and second component path 514n, respectively. Pre-filter section 522n includes filters 523n and 525n, which filter the first and second components as described above. The filtered signals are fed to pre-amplifier section 524n, which includes LNAs 527n and 529n configured to amplify the respective filtered component. The amplified components are fed to a processing engine 530, which is substantially similar to processing engine 330 described above.

[0078] Fig. is a flowchart of an exemplary calibration process 600 according to an exemplary implementation. The process 600 may be implemented as instructions stored in memory that may be executed by a controller (e.g., the controller of the processing engine 330) to calibrate the receiver 500 from Fig. and one or more sub-receivers 505a-505n from Fig. to calibrate. The calibration process 600 may be performed by a receiver (or sub-receiver) to select a signal for use in determining a location of the receiver based on positioning signals (e.g., positioning signals 174A-174C) from a positioning system.

[0079] In block 602, the calibration mode may be triggered, e.g., a controller of the receiver (or sub-receiver) may cause the receiver to enter calibration mode. For example, a circularly polarized signal may be received at an antenna (e.g., antenna 310, antenna 510a, and / or antenna 510b), and linearly polarized components of the circularly polarized signal may be detected. In some examples, as described above, linearly polarized components of a circularly polarized signal may be amplified and passed to a processing engine for downconversion and demodulation to obtain the location information contained therein, as described above. Prior to downconversion and demodulation, the receiver (or sub-receiver) may enter calibration mode in block 602.

[0080] In block 604, a first linearly polarized component of the circularly polarized signal may be read for a calibration time window (Tc) to obtain a first signal power. For example, a receiver (or, depending on the implementation, a sub-receiver) may detect the first linearly polarized component (e.g., the vertically linearly polarized component) using an antenna and measure a signal power of the first linearly polarized component over the calibration time window. The calibration time window may be predefined on a first time scale (e.g., 10 seconds, 20 seconds, 1 minute, etc.). In some examples, the first linearly polarized component may be transmitted to a processing engine via a first component path, as described above in connection with the Fig. described. As such, the first signal power may be measured from a signal output of an LNA or before amplification of the LNA. The signal power may be specified here as one or more of a received signal level (RSSI) and a carrier-to-noise level (C / N). For example, processing engine 330 may receive read outputs from front-end 320 and provide an RSSI and / or C / N value.

[0081] In block 606, a second linearly polarized component of the circularly polarized signal may be read for the calibration time window (Tc) to obtain a second signal power. For example, a receiver (or sub-receiver depending on the implementation) may detect the second linearly polarized component (e.g., the horizontal linearly polarized component) using an antenna and measure a signal power of the second linearly polarized component over the calibration time window. In some examples, the second linearly polarized component may be communicated to a processing engine via a second component path, as described above in connection with the Fig. As such, the second signal power can be measured from a signal output of an LNA or before the LNA is amplified.

[0082] In determination block 608, the first signal power is compared to the second signal power to determine if the first signal power is greater than the second signal power. If the determination is positive, the calibration process 600 proceeds to block 610, where the first linearly polarized component may be selected. Conversely, if the determination is negative, the calibration process 600 proceeds to block 612 to select the second linearly polarized component. For example, the controller may determine that the first signal power is greater than the second signal power, identify the first signal power as optimal for use in obtaining position information (e.g., the greatest signal power), and select the linearly polarized component that corresponds to the identified signal power.

[0083] In block 614, the linearly polarized component selected in block 610 or block 612 may be used to obtain location information. For example, a controller may downconvert and demodulate the selected linearly polarized component to obtain the location information contained therein and determine the geographic coordinates of the receiver, as described above.

[0084] In determination block 616 it is determined whether a measurement time window (T P ) has elapsed or not. The measurement time window (T P) can be set in advance to define a period of time until the receiver may need to be recalibrated. For example, as the satellites of a positioning system orbit the Earth, the position of the satellites changes relative to the receiver, especially to a stationary receiver. When the positions of the satellites change, the path of the positioning signals transmitted by the satellites to the receiver changes, which may result in a change in the number of reflections and / or a change in the signal strength of the circularly polarized signal. Because positions change due to orbits, the satellites from which a signal is received may also change (e.g., a signal from a particular satellite may no longer be received and a signal may be received from a new satellite).These changes can affect which linearly polarized component provides the greater signal power, so the receiver may need to be recalibrated to ensure that the optimal linearly polarized component is used to obtain location information. Therefore, the measurement time window (T P ) to a second time scale that is larger than the first time scale to account for position changes. The measurement time window (T P ) can be set to 30 minutes or more in some cases, e.g., 1 hour, 4 hours, 5 hours, etc. In some examples, the measurement time window (T P ) are not restricted by the first time scale. In this case, the measurement time window (T P ) are on the order of seconds or milliseconds.

[0085] If the determination in determination block 616 is negative, the calibration process 600 returns to block 614 and continues to use the linearly polarized component selected in block 612 or block 610. If, however, the determination is positive, the calibration process 600 returns to block 602 and initiates calibration mode to recalibrate the receiver (or sub-receiver).

[0086] In an example, the process 600 may be performed for each measurement time window (T P ) and the determinations are saved for post-processing. In this case, process 600 may not select a component to obtain location information until the saved determinations have been processed to identify the largest component signal from the scan. Process 600 may then use this component signal to obtain location information.

[0087] Fig. is a schematic block diagram of another example of a receiver 700 in accordance with the present disclosure. Receiver 700 may be substantially similar to receiver 300 of Fig. except that a phase calibration mechanism 716 and a combiner 718 are provided along at least one of the component paths. Thus, the antenna 710, which receives circularly polarized signals received from a positioning system (e.g., the positioning system 170 of Fig. radiated, are substantially similar to the antenna 310. Similarly, the RF front end 720, the pre-filter section 722, the filter 723, the pre-amplifier section 724, the LNA 727, and the processing module 730 may be similar to the RF front end 320, the pre-filter section 322, the filter 323, the pre-amplifier section 324, the LNA 327, and the processing module 330 of Fig. be essentially similar.

[0088] In the example of Fig. The phase calibration mechanism 716 is provided along the first component path 712, and the combiner 718 is connected to both the first and second component paths 712 and 714. The phase calibration mechanism 716 may be configured to adjust a phase of the first component of a circularly polarized signal received by the antenna 710, which may be substantially similar to the antenna 310 and / or the antenna 510a, thereby inducing a phase delay of the first component. The phase calibration mechanism 716 may include combinations of inductors and capacitor circuits and / or different transmission line lengths that introduce phase delays. In some examples, the phase calibration mechanism 716 may be a semiconductor-based phase delay integrated circuit.While in the present example the phase calibration mechanism 716 is provided in the first component path 712, in another example the phase calibration mechanism 716 may be provided in the second component path 714 to delay the phase of the second component.

[0089] The combiner 718 may be configured to generate a combined circularly polarized signal based on the combination of the phase-delayed first component with the second component. For example, the combiner 718 receives both components from the first and second component paths at the inputs and outputs a combined circularly polarized signal at an output. In one illustrative example, the combiner 718 may be an RHCP combiner that generates a combined RHCP signal by combining the phase-delayed first component with the second component. In this case, the first component may lag behind the second component due to the phase delay, and the resulting combined signal has RHCP. In another example, the combiner 718 may generate a combined LHCP signal.

[0090] In addition, as described above, the receivers may need to operate in different L-bands. Accordingly, a receiver may comprise a plurality of sub-receivers, each of which is substantially the same as the Fig. shown receiver 700, each corresponding to a different L-band (e.g., L1, L2, L5, etc.), similar to that shown in Fig. example shown.

[0091] Fig. is a flowchart of another example of a calibration process 800 according to an example implementation. The process 800 may be implemented as instructions stored in memory that may be executed by a control unit (e.g., the control unit of the processing engine 730) to calibrate the receiver 700 from Fig. to calibrate. The calibration process 800 may be performed by a receiver (or sub-receiver) to select a signal for use in determining a location of the receiver based on positioning signals (e.g., positioning signals 174A-174C) from a positioning system.

[0092] In block 802, the calibration mode may be triggered, e.g., a controller of the receiver (or sub-receiver) may cause the receiver to enter calibration mode. For example, a circularly polarized signal may be received at an antenna (e.g., antenna 710) and linearly polarized components of the circularly polarized signal may be detected (block 804). In some examples, as described above, linearly polarized components of a circularly polarized signal may be amplified and passed to a processing engine for downconversion and demodulation to obtain the location information contained therein, as described above. Prior to downconversion and demodulation, the receiver (or sub-receiver) may enter calibration mode in block 802.

[0093] In block 804, the first and second components are read for a calibration time window (Tc). For example, a receiver (or, depending on the implementation, a sub-receiver) with an antenna may acquire the first and second linearly polarized components (e.g., the horizontal linearly polarized component) over the calibration time window. The calibration time window may be preset to a first time scale (e.g., 10 seconds, 20 seconds, 1 minute, etc.).

[0094] In block 806, a phase shift value and a maximum sample value may be specified. In one example, the phase shift value may be set to zero and the maximum sample value to 180 degrees. In some cases, block 806 may also include setting a step value for incrementing the phase shift value. In some examples, the step value may be set to 5 degrees, but other step values may be applicable depending on the desired granularity.

[0095] In block 808, a combined circularly polarized signal may be generated and a signal power of the combined circularly polarized signal may be measured. For example, the first and second components may be passed to combiner 718 and combined by combiner 718 to output a circularly polarized signal (e.g., RHCP in some examples). Note that phase calibration mechanism 716 is set to zero the first time and does not adjust the phase of the first component the first time. In one example, measuring signal power may include measuring the collective energy power (e.g., RSSI) of the combined circularly polarized signal. In another example, measuring signal power may include evaluating a C / N value of a decoded satellite or a plurality of satellites.

[0096] In determination block 810, the measured signal power is compared with a previous signal power to determine whether the currently measured signal power is greater than the previous signal power. If so, the current phase shift value is stored in a memory of the processing engine 730 in block 812, and the phase shift value is incremented by the step size in block 814. If the current signal power is less than the previous signal power, the phase shift value is incremented by the step size in block 814 without storing the current phase shift value.

[0097] In determination block 816, the current phase shift value is compared to the maximum scan value to determine if the scan is complete. If not, the calibration process 800 returns to block 808 and repeats blocks 808-816 for the next step value, which is incremented by block 816.

[0098] Otherwise, the calibration process 800 proceeds to block 818 and obtains location information using a combined circularly polarized signal generated according to the stored phase shift value. That is, by iteratively incrementing the phase shift value and storing the phase shift value associated with the greatest signal power, the circularly polarized signal with the greatest signal power can be identified and selected for obtaining location information. The controller can downconvert and demodulate the selected circularly polarized signal to obtain the location information contained therein and determine the geographic coordinates of the receiver, as described above.

[0099] In the determination block 820 it is determined whether a measurement time window (T P ) has elapsed or not. The measurement time window (T P) can be set in advance to define a period of time until the receiver may need to be recalibrated. Block 820 can be essentially similar to block 616 of Fig. If the determination in determination block 820 is negative, the calibration process 800 returns to block 818 and continues using the combined circularly polarized signal to obtain location information. If, however, the determination is positive, the calibration process 800 returns to block 802 and initiates calibration mode to recalibrate the receiver (or sub-receiver).

[0100] Note that regardless of how many reflections the satellite signal undergoes, the calibration process 800 captures the two linear components and processes them separately, calibrating one of them to change its phase and produce a combined circularly polarized signal. In implementations where the receiver 700 is included in APs, APs are generally stationary devices, so the environment does not change much over time, and the reflected wave captured by the antenna exhibits the same behavior over time.

[0101] Fig. is a schematic block diagram of another example of a receiver 900 according to implementations of the present disclosure. The receiver 900 may provide the receiver 300 with Fig. be substantially similar, except that a switch 916 and a circular polarization combiner 918 are provided along the first and second component paths 912 and 914. Thus, the antenna 910, which receives circularly polarized signals received from a positioning system (e.g., the positioning system 170 of Fig. radiated, are substantially similar to the antenna 310. Similarly, the RF front end 920, the pre-filter section 922, the filter 923, the pre-amplifier section 924, the LNA 927, and the processing engine 930 may be similar to the RF front end 320, the pre-filter section 322, the filter 323, the pre-amplifier section 324, the LNA 327, and the processing engine 330 of Fig. be essentially similar.

[0102] In the example of Fig. The switch 916 can connect two inputs to two outputs. The switch 916 can be controlled by changing its configuration to switch which input is connected to which output. As shown in Fig. For example, as shown, the first component path 912 may be connected to a first input, while the second component path 914 may be connected to a second input. A first output 911 and a second output 913 may be connected to the circular polarization combiner 918. The switch 916 may be implemented, for example, as a DPDT diamond switch or as any switch that can accept two inputs and interchangeably connect them to two outputs.

[0103] In a first configuration, the first input may connect the first component path 912 to the first output 911 such that the first component is forwarded to the first output 911, and the second input may connect the second component path 914 to the second output 913 such that the second component is forwarded to the second output 913.

[0104] Switch 916 can be controlled to switch to a second configuration in which the outputs are reversed. For example, in the second configuration, the first input can connect the first component path 912 to the second output 913, such that the first component is routed to the second output 913, and the second input can connect the second component path 914 to the first output 911, such that the second component is routed to the first output 911.

[0105] The circular polarization combiner 918 may have a first input connected to the first output 911 and a second input connected to the second output 913. The circular polarization combiner 918 may be connected to the combiner 718 of Fig. be similar, such that the circular polarization combiner 918 is configured to generate a combined circularly polarized signal based on the combination of the first and second components at the inputs and generate a combined circularly polarized signal at an output of the circular polarization combiner 918. When the switch 916 is in the first configuration, the first component at the first output 911 is combined with the second component at the second output 913 to generate a first circularly polarized signal. Conversely, when the switch 916 is in the second configuration, the second component at the first output 911 is combined with the first component at the second output 913 to generate a second circularly polarized signal having a direction of rotation opposite to the first circularly polarized signal.For example, if the first component is vertically linearly polarized and the second component is horizontally linearly polarized, the first circularly polarized signal may have RHCP when switch 916 is in the first configuration, and the second circularly polarized signal may have LHCP when switch 916 is in the second configuration.

[0106] In addition, as described above, the receivers may need to operate in different L-bands. Accordingly, a receiver may comprise a plurality of sub-receivers, each of which is substantially the same as the Fig. shown receiver 900, each corresponding to a different L-band (e.g., L1, L2, L5, etc.), similar to that shown in Fig. example shown.

[0107] Fig. is a flowchart of another example of a calibration process 1000 according to an example implementation. The process 1000 may be implemented as instructions stored in memory that may be executed by a control unit (e.g., the control unit of the processing engine 930) to calibrate the receiver 900 from Fig. to calibrate. The calibration process 1000 may be performed by a receiver (or sub-receiver) to select a signal for use in determining a location of the receiver based on positioning signals (e.g., positioning signals 174A-174C) from a positioning system.

[0108] In block 1002, the calibration mode may be triggered, e.g., a controller of the receiver (or sub-receiver) may cause the receiver to enter calibration mode. For example, a circularly polarized signal may be received at an antenna (e.g., antenna 910), and linearly polarized components of the circularly polarized signal may be detected. In some examples, as described above, linearly polarized components of a circularly polarized signal may be amplified and passed to a processing engine for downconversion and demodulation to obtain the location information contained therein, as described above. Prior to downconversion and demodulation, the receiver (or sub-receiver) may enter calibration mode in block 1002.

[0109] In block 1004, a switch may be configured in a first configuration. For example, as described above, switch 916 may be controlled via processing engine 930 to connect first component path 912 to first output 911 and second component path 914 to second output 913. In this configuration, the first component may be routed to first output 911 and the second component to second output 913 for a calibration time window (Tc). As described above, the calibration time window may be predefined on a first time scale (e.g., 10 seconds, 20 seconds, 1 minute, etc.).

[0110] In block 1006, a combined first circularly polarized signal may be generated by combining the first and second components. For example, the first component may be passed to the circular polarization combiner 918 via the first output 911, while the second component may be passed to the circular polarization combiner 918 via the second output 913. The first and second components may be combined by the circular polarization combiner 918 to output the first combined circularly polarized signal (e.g., RHCP in some examples).

[0111] In block 1008, a first signal power of the first combined circularly polarized signal may be measured.

[0112] In block 1010, the switch may be switched to a second configuration. For example, as described above, switch 916 may be controlled via processing engine 930 to connect first component path 912 to second output 913 and second component path 914 to first output 911. In this configuration, the first component may be routed to second output 913 and the second component to first output 911 for the calibration time window (Tc).

[0113] In block 1012, a second signal power of a second combined circularly polarized signal may be measured. The second combined circularly polarized signal may, for example, be generated by combining the first and second components. That is, the first component may be passed to the circular polarization combiner 918 via the second output 913, while the second component may be passed to the circular polarization combiner 918 via the first output 911. The first and second components may be combined by the circular polarization combiner 918 to output the second combined circularly polarized signal having a rotation direction opposite to the first combined circularly polarized signal (e.g., LHCP in some examples). The signal power of the second combined circularly polarized signal may thus be measured in block 1012.

[0114] In determination block 1014, the first signal power is compared to the second signal power to determine whether the first signal power is greater than the second signal power. If the determination is positive, the calibration process 1000 proceeds to block 1016, where the first combined circularly polarized component can be selected and the switch can be configured according to the first configuration. If, however, the determination is negative, the calibration process 1000 proceeds to block 1018 to select the second combined circularly polarized component and configure the switch according to the second configuration.

[0115] In block 1020, the combined circularly polarized component selected in block 1016 or block 1018 may be used to obtain location information. For example, a controller may downconvert and demodulate the selected combined circularly polarized component to obtain the location information contained therein and resolve the geographic coordinates of the receiver, as described above.

[0116] In determination block 1022 it is determined whether a measurement time window (T P ) has elapsed or not. The measurement time window (T P ) can be set in advance to define a period of time until the receiver may need to be recalibrated. Block 1022 can essentially correspond to block 616 of Fig. If the determination in determination block 1022 is negative, the calibration process 1000 returns to block 1020 and continues to use the selected combined circularly polarized signal to obtain location information. If, however, the determination is positive, the calibration process 1000 returns to block 1002 and initiates calibration mode to recalibrate the receiver (or sub-receiver).

[0117] Fig. shows a block diagram of an example computer system 1100 in which various of the examples described herein may be implemented. The computer system 1100 may be implemented as a network controller 104 of Fig. , processing machine 330 or controller 332 of Fig. , processing machine 530a or processing machine 530b (or controller therein), processing machine 730 of Fig. and / or processing machine 930 from Fig. be implemented. The computer system 1100 includes a bus 1102 or other communication mechanism for transmitting information, and one or more hardware processors 1104 connected to the bus 1102 for processing information. The hardware processor(s) 1104 may be, for example, one or more general-purpose microprocessors.

[0118] Computer system 1100 also includes a main memory 1106, such as random access memory (RAM), a cache, and / or other dynamic storage devices, connected to bus 1102 to store information and instructions to be executed by processor 1104. Main memory 1106 may also be used to store temporary variables or other intermediate information during the execution of instructions to be executed by processor 1104. When such instructions are stored in storage media accessible to processor 1104, computer system 1100 becomes a special-purpose machine adapted to perform the operations specified in the instructions. In some examples, main memory 1106 may store instructions that may be executed by processor 1104 to perform the operations associated with the Fig. to carry out the operations described.

[0119] Computer system 1100 also includes a read-only memory (ROM) 1108 or other static storage device connected to bus 1102 for storing static information and instructions for processor 1104. A storage device 1110, such as a magnetic disk, an optical disk, or a USB flash drive, etc., is provided and connected to bus 1102 for storing information and instructions.

[0120] Computer system 1100 may be connected to a display 1112, such as a liquid crystal display (LCD) (or a touchscreen), via bus 1102 to display information to a computer user. An input device 1114, including alphanumeric and other keys, is coupled to bus 1102 to communicate information and command selections to processor 1104. Another type of user input device is cursor control 1116, such as a mouse, trackball, or cursor direction keys, for communicating direction information and command selections to processor 1104 and controlling cursor movement on display 1112. In some embodiments, the same direction information and command selections as with cursor control may be implemented via receiving touches on a touchscreen without a cursor.

[0121] Computer system 1100 may include a user interface module for implementing a graphical user interface, which may be stored on a mass storage device as executable software code executed by the computing device(s). This and other modules may include, for example, components such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables.

[0122] In general, the terms “component,” “engine,” “system,” “database,” “data store,” and the like, as used herein, may refer to logic embodied in hardware or firmware, or to a collection of software instructions that may have entry and exit points and be written in a programming language such as Java, C, or C++. A software component may be compiled and linked into an executable program, installed in a dynamic link library, or written in an interpreted programming language such as BASIC, Perl, or Python. It is understood that software components may be callable by other components or by themselves, and / or may be called in response to detected events or interrupts. Software components configured to run on computing devices may be embodied on a computer-readable medium, such as a hard disk.a compact disc, digital video disc, flash drive, magnetic disk, or other tangible medium, or as a digital download (and may be originally stored in a compressed or installable format that requires installation, decompression, or decryption before execution). Such software code may be stored partially or entirely in a memory of the executing computing device so that it can be executed by the computing device. Software instructions may be embedded in firmware, such as an EPROM. In addition, the hardware components may consist of connected logic units such as gates and flip-flops and / or programmable units such as programmable gate arrays or processors.

[0123] Computer system 1100 may implement the techniques described herein using custom hard-wired logic, one or more ASICs or FPGAs, firmware, and / or program logic that, in combination with the computer system, causes or programs computer system 1100 to be a special-purpose machine. According to one embodiment, the techniques described herein are performed by computer system 1100 in response to processor(s) 1104 executing one or more sequences of one or more instructions contained in main memory 1106. Such instructions may be read into main memory 1106 from another storage medium, such as storage device 1110. Execution of the instruction sequences contained in main memory 1106 causes processor(s) 1104 to perform the process steps described herein.In alternative embodiments, hard-wired circuits may be used instead of or in combination with software instructions.

[0124] The term "non-volatile media" and similar terms as used herein refer to any media that stores data and / or instructions that cause a machine to operate in a particular manner. Such non-volatile media may include non-volatile media and / or volatile media. Non-volatile media includes, for example, optical or magnetic disks, such as storage device 1110. Volatile media includes dynamic memory, such as main memory 1106. Common forms of non-volatile media include, for example, floppy disks, flexible disks, hard disks, solid-state drives, magnetic tape or other magnetic data storage media, CD-ROMs, other optical data storage media, physical media with hole patterns, RAM, PROM and EPROM, FLASH EPROM, NVRAM, other memory chips or cartridges, and networked versions thereof.

[0125] Non-transitory media are distinct from transmission media but can be used in conjunction with them. Transmission media are involved in the transfer of information between non-transitory media. Examples of transmission media include coaxial cable, copper wire, and fiber optic cable, including the wires that make up bus 1102. Transmission media can also take the form of sound or light waves, such as those generated in data communications via radio and infrared.

[0126] Computer system 1100 also includes a communications interface 1118 connected to bus 1102. Communications interface 1118 establishes a bidirectional data communications connection to one or more network connections connected to one or more local area networks. For example, communications interface 1118 may be an Integrated Services Digital Network (ISDN) card, a cable modem, a satellite modem, or a modem for establishing a data communications connection to a corresponding type of telephone line. As another example, communications interface 1118 may be a Local Area Network (LAN) card for establishing a data communications connection to a compatible LAN (or a WAN component for communicating with a WAN). Wireless connections may also be implemented.In each of these implementations, the communication interface 1118 sends and receives electrical, electromagnetic, or optical signals that carry digital data streams containing various types of information.

[0127] A network connection typically enables data communication across one or more networks to other data devices. For example, a network connection may connect across a local area network to a host computer or to data devices of an Internet service provider (ISP). The ISP, in turn, provides data communication services over the worldwide packet data communication network, now commonly referred to as the "Internet." Both the local area network and the Internet use electrical, electromagnetic, or optical signals that carry digital data streams. The signals in the various networks and the signals on the network connection and across the communication interface 1118 that carry the digital data to and from the computer system 1100 are examples of transmission media.

[0128] Computer system 1100 can send messages and receive data, including program code, over the network(s), the network connection, and the communications interface 1118. In the Internet example, a server could transmit requested code for an application program over the Internet, the ISP, the local network, and the communications interface 1118.

[0129] The received code may be executed by processor 1104 upon receipt and / or stored in storage device 1110 or other non-volatile memory for later execution.

[0130] Each of the processes, methods, and algorithms described in the preceding sections may be embodied in, and fully or partially automated by, code components executed by one or more computer systems or computer processors comprising computer hardware. The one or more computer systems or computer processors may also operate to support the performance of the corresponding operations in a cloud computing environment or as software as a service (SaaS). The processes and algorithms may be partially or fully implemented in application-specific circuitry. The various features and methods described above may be used independently or combined in various ways.Various combinations and subcombinations are intended to be within the scope of this disclosure, and certain method or process blocks may be omitted in some implementations. The methods and processes described herein are also not limited to any particular order, and the associated blocks or states may be performed in other suitable orders, in parallel, or otherwise. Blocks or states may be added to or removed from the disclosed examples. The execution of certain operations or processes may be distributed among computer systems or computer processors located not only in a single machine, but distributed across a number of machines.

[0131] A circuit may be implemented in any form of hardware, software, or a combination thereof. For example, one or more processors, controllers, ASICs, PLAs, PALs, CPLDs, FPGAs, logic components, software routines, or other mechanisms may be implemented to form a circuit. In implementation, the various circuits described herein may be implemented as discrete circuits, or the described functions and features may be distributed, in part or in whole, among one or more circuits. Even though various features or functional elements are individually described or claimed as separate circuits, those features and functions may be shared by one or more common circuits, and such description is not intended to assume or imply that separate circuits are required to implement those features or functions.If a circuit is implemented in whole or in part with software, that software may be implemented to operate with a computer or processing system capable of performing the functionality described with respect thereto, such as computer system 1100.

[0132] As used herein, the term "or" can be interpreted in both an inclusive and an exclusive sense. Furthermore, descriptions of resources, acts, or structures in the singular should not be construed as excluding the plural. Conditional expressions such as "may," "could," "might," or "may," unless expressly stated otherwise or understood by context, are generally understood to imply that certain embodiments include certain features, elements, and / or steps, while other embodiments do not.

[0133] Unless expressly stated otherwise, the terms and expressions used in this document, as well as their variations, are not to be interpreted as limiting but as open-ended. Adjectives such as "conventional," "traditional," "normal," "standard," "known," and terms of similar import are not to be construed as limiting the subject matter described to a particular period of time or to a subject matter available at a particular time, but should be understood to include conventional, traditional, normal, or standard technologies that may be available or known now or at any time in the future.The presence of broader words and phrases such as “one or more,” “at least,” “but not limited to,” or similar phrases in some cases should not be construed as meaning that the narrower case is intended or required in the absence of such broader phrases.

Claims

[1] A method for tuning an access point, comprising: Reception of a circularly polarized signal by an antenna of the access point; Obtaining a first linearly polarized component of the circularly polarized signal and a second linearly polarized component of the circularly polarized signal; identifying a signal having the greatest signal power based on a comparison of the first and second linearly polarized components; Obtaining geographical coordinates for the access points from the identified signal; and Connection to a network based on the determined geographical coordinates. [2] The method of claim 1, wherein the circularly polarized signal is a right-handed circularly polarized signal. [3] The method of claim 2, wherein the circularly polarized signal is a Global Navigation Satellite System (GNSS) signal. [4] The method of claim 1, wherein the first linearly polarized component is orthogonal to the second linearly polarized component. [5] The method according to claim 1 further comprises: Determining that a first signal power of the first linearly polarized component is greater than a second signal power of the second linearly polarized component by comparing the first signal power with the second signal power, where the identified signal is the first linearly polarized component. [6] The method according to claim 1 further comprises: iterative application of a plurality of phase delays to the first linearly polarized component; for each phase delay from the multitude of phase delays, Combining the phase-delayed first linearly polarized component with the second linearly polarized component to produce a combined signal, and Determining a signal power of the combined signal; and Identification of a combined signal from the multitude of phase delays with the greatest signal power, where the identified signal is the identified combined signal. [7] The method of claim 6, wherein the combined signal is a circularly polarized signal. [8] The method according to claim 1 further comprises: inputting the first linearly polarized component to a first input of a switch and the second linearly polarized component to a second input of the switch to output a first combined circularly polarized signal; Inputting the first linearly polarized component into the second input of a switch and the second linearly polarized component into the first input of a switch to output a second combined circularly polarized signal; and Determining that a first signal power of the first combined circularly polarized signal is greater than a second signal power of the second combined circularly polarized signal by comparing the first signal power with the second signal power, where the identified signal is the first combined circularly polarized signal. [9] The method of claim 8, wherein the first combined circularly polarized signal is a right-handed circularly polarized signal, and wherein the second combined circularly polarized signal is a left-handed circularly polarized signal. [10] Access point consisting of: an antenna; a memory that stores instructions; and at least one processor communicatively coupled to the antenna and the memory and configured to execute the instructions to: to receive a position signal from a positioning system through the antenna, the positioning signal comprising a right-handed polarized signal; obtain a first linearly polarized component of the position signal and a second linearly polarized component of the position signal; selecting a signal having the greatest signal power based on a comparison of the first and second linearly polarized components; to determine geographical coordinates for the access points based on the selected signal; and To provide network services based on the determined geographical coordinates. [11] The access point of claim 10, wherein the antenna is a dual polarized antenna. [12] The access point of claim 10, wherein the positioning signal is a global navigation satellite system (GNSS) signal. [13] The access point of claim 10, wherein the first linearly polarized component is a vertically linearly polarized component and the second linearly polarized component is a horizontally linearly polarized component. [14] The access point of claim 10, wherein the at least one processor is further configured to execute the instructions to: Determining that a first signal power of the first linearly polarized component is greater than a second signal power of the second linearly polarized component by comparing the first signal power with the second signal power, where the selected signal is the first linearly polarized component. [15] An access point according to claim 10, further comprising: a phase calibration mechanism connected to the antenna; and a combiner connected to the phase calibration mechanism. [16] The access point of claim 15, wherein the at least one processor is further configured to execute the instructions to: iteratively applying a plurality of phase delays to the first linearly polarized component through the phase calibration mechanism; for each phase delay from the multitude of phase delays, Combining the phase-delayed first linearly polarized component with the second linearly polarized component by the combiner to produce a combined signal, and to determine a signal power of the combined signal; and Identification of a combined signal from the multitude of phase delays with the greatest signal power, where the selected signal is the identified combined signal. [17] An access point according to claim 10, further comprising: a switch having a first input and a second input connected to the antenna; and a circular polarization combiner having a first input connected to a first output of the switch and a second input connected to a second output of the switch. [18] The access point of claim 17, wherein the at least one processor is further configured to execute the instructions to: Configuring the switch in a first configuration, wherein, when in the first configuration, the first linearly polarized component is directed into the first input of the switch and the second linearly polarized component is directed into the second input of the switch in the first configuration; Outputting a first combined circularly polarized signal from the circular polarization combiner when the switch is in the first configuration; Configuring the switch in a second configuration, wherein, when in the second configuration, the first linearly polarized component is fed into the second input of the switch and the second linearly polarized component is fed into the first input of the switch; Outputting a second combined circularly polarized signal from the circular polarization combiner when the switch is in the second configuration; and Determining that a first signal power of the first combined circularly polarized signal is greater than a second signal power of the second combined circularly polarized signal by comparing the first signal power with the second signal power, where the selected signal is the first combined circularly polarized signal. [19] GNSS receiver (Global Navigation Satellite System), consisting of: a dual-polarized antenna configured to detect a first linearly polarized component of a GNSS signal and a second linearly polarized component of a GNSS signal; and a control unit connected to the dual-polarized antenna, the control unit configured to select an optimal signal based on a comparison including the first and second linearly polarized components and to resolve geographic coordinates using the optimal signal. [20] The GNSS receiver of claim 19, wherein the selection of the optimal signal is based on identifying a signal having the greatest signal power from the comparison comprising the first and second linearly polarized components.

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