WO2023096647A1

WO2023096647A1 - Apparatus and method of pseudo-range measurement correction for position determination

Info

Publication number: WO2023096647A1
Application number: PCT/US2021/060840
Authority: WO
Inventors: Yi-Hsiu Wang; Arkady Molev-Shteiman
Original assignee: Zeku, Inc.
Priority date: 2021-11-24
Filing date: 2021-11-24
Publication date: 2023-06-01

Abstract

According to one aspect of the present disclosure, a global navigation satellite system (GNSS) receiver is provided. The GNSS receiver may include a navigation circuit. The navigation circuit may be configured to estimate a first position associated with the GNSS receiver based on one or more GNSS signals associated with a first plurality of satellite vehicles (SVs). The navigation circuit may be configured to obtain a three-dimensional (3D) virtual map associated with the first position. The navigation circuit may be configured to identify a non-line-of-sight (NLOS) satellite vehicle (SV) based on the first position and the 3D virtual map. The navigation circuit may be configured to estimate a second position associated with the GNSS receiver by correcting a pseudo-range measurement associated with the NLOS SV and used to estimate the first position.

Description

APPARATUS AND METHOD OF PSEUDO-RANGE MEASUREMENT CORRECTION FOR POSITION DETERMINATION

BACKGROUND

[0001] Embodiments of the present disclosure relate to apparatus and method for wireless communication.

[0002] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. In wireless local area network (WLAN) communication (e.g., such as Wi-Fi) and in cellular communication (e.g., such as the 4th-generation (4G) Long Term Evolution (LTE) and the 5th-generation (5G) New Radio (NR)), the Institute of Electrical and Electronics Engineers (IEEE) and the 3rd Generation Partnership Project (3 GPP) define various operations for global navigation satellite system (GNSS) navigation.

SUMMARY

[0003] According to one aspect of the present disclosure, a GNSS receiver is provided. The GNSS receiver may include a navigation circuit. The navigation circuit may be configured to estimate a first position associated with the GNSS receiver based on one or more GNSS signals associated with a first plurality of satellite vehicles (SVs). The navigation circuit may be configured to obtain a three-dimensional (3D) virtual map associated with the first position. The navigation circuit may be configured to identify a non-line-of-sight (NLOS) satellite vehicle (SV) based on the first position and the 3D virtual map. The navigation circuit may be configured to estimate a second position associated with the GNSS receiver by correcting a pseudo-range measurement associated with the NLOS SV and used to estimate the first position.

[0004] According to another aspect of the disclosure, a cloud server is provided. The cloud server may include at least one processor. The cloud server may include memory storing instruction that, when executed by the at least one processor, causes the cloud server at least to receive position information from a plurality of GNSS receivers. The position information may include GNSS receiver information and SV information. The SV information includes a plurality of multi-path profiles associated with a plurality of SVs. The cloud server may include memory storing instruction that, when executed by the at least one processor, generate a 3D virtual map based on the GNSS receiver information and the SV information. The position information may include one or more pseudo-range measurements corrected by at least one GNSS receiver.

[0005] According to yet another aspect of the disclosure, a method of wireless communication of a GNSS receiver is provided. The method may include estimating, by a navigation circuit, a first position associated with the GNSS receiver based on one or more GNSS signals associated with a first plurality of SVs. The method may include obtaining, by the navigation circuit, a 3D virtual map associated with the first position. The method may include identifying, by the navigation circuit, an NLOS SV based on the first position and the 3D virtual map. The method may include estimating, by the navigation circuit, a second position associated with the GNSS receiver by correcting a pseudo-range measurement associated with the NLOS SV and used to estimate the first position.

[0006] According to still another aspect of the disclosure, a method of a server device is provided. The method may include receiving, by a processor, position information from a plurality of GNSS receivers. The position information includes GNSS receiver information and SV information. The SV information includes a plurality of multi-path profiles associated with a plurality of SVs. The method may include generating, by the processor, a 3D virtual map based on the GNSS receiver information and the SV information.

[0007] These illustrative embodiments are mentioned not to limit or define the present disclosure, but to provide examples to aid understanding thereof. Additional embodiments are discussed in the Detailed Description, and further description is provided there.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable a person skilled in the pertinent art to make and use the present disclosure.

[0009] FIG. 1 A illustrates a diagram of a line-of-sight (LOS) signal and an NLOS signal received by a GNSS receiver.

[0010] FIG. IB illustrates a graphical illustration of a channel impulse response associated with far-field multi-path depicted in FIG. 1 A.

[0011] FIG. 1C illustrates a graphical representation of a time-domain overlap and a time/frequency-domain overlap LOS and NLOS signals associated with the far-field multi-path depicted in FIG. 1 A.

[0012] FIG. ID illustrates a graphical illustration of two NLOS SVs blocked from view by two GNSS receivers.

[0013] FIG. 2 illustrates an exemplary wireless network, according to some embodiments of the present disclosure.

[0014] FIG. 3 illustrates a block diagram of an apparatus including a GNSS receiver, a wireless network interface, and a host chip, according to some embodiments of the present disclosure.

[0015] FIG. 4 illustrates a block diagram of an exemplary node, according to some embodiments of the present disclosure.

[0016] FIG. 5 A illustrates a diagram of a multi-path scenario in which the exemplary multipath mitigation technique may be applied by a GNSS receiver, according to some embodiments of the present disclosure.

[0017] FIG. 5B illustrates a diagram of SV mirror-image geometry that may be used by the GNSS receiver to perform the exemplary multi-path mitigation technique associated with the multi-path scenario depicted in FIG. 5 A, according to some embodiments of the present disclosure. [0018] FIG. 5C illustrates a diagram of GNSS mirror-image geometry that may be used by the GNSS receiver to perform the exemplary multi-path mitigation technique associated with the multi-path scenario depicted in FIG. 5 A, according to some embodiments of the present disclosure. [0019] FIG. 5D illustrates a diagram of estimating a position of an NLOS SV based on the GNSS mirror-image geometry of FIG. 5C, according to some embodiments of the present disclosure.

[0020] FIG. 6A illustrates a first flowchart of a method for wireless communication, according to some embodiments of the present disclosure.

[0021] FIG. 6B illustrates a flowchart of 3D virtual map generation, according to some embodiments of the present disclosure.

[0022] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

DETAILED DESCRIPTION

[0023] Although specific configurations and arrangements are discussed, it should be understood that this is done for illustrative purposes only. A person skilled in the pertinent art will recognize that other configurations and arrangements can be used without departing from the spirit and scope of the present disclosure. It will be apparent to a person skilled in the pertinent art that the present disclosure can also be employed in a variety of other applications.

[0024] It is noted that references in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” “some embodiments,” “certain embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it would be within the knowledge of a person skilled in the pertinent art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0025] In general, terminology may be understood at least in part from usage in context. For example, the term “one or more” as used herein, depending at least in part upon context, may be used to describe any feature, structure, or characteristic in a singular sense or may be used to describe combinations of features, structures or characteristics in a plural sense. Similarly, terms, such as “a,” “an,” or “the,” again, may be understood to convey a singular usage or to convey a plural usage, depending at least in part upon context. In addition, the term “based on” may be understood as not necessarily intended to convey an exclusive set of factors and may, instead, allow for existence of additional factors not necessarily expressly described, again, depending at least in part on context.

[0026] Various aspects of wireless communication systems will now be described with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, units, components, circuits, steps, operations, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, firmware, computer software, or any combination thereof. Whether such elements are implemented as hardware, firmware, or software depends upon the particular application and design constraints imposed on the overall system.

[0027] The techniques described herein may be used for various wireless communication networks, such as code division multiple access (CDMA) system, time division multiple access (TDMA) system, frequency division multiple access (FDMA) system, orthogonal frequency division multiple access (OFDMA) system, single-carrier frequency division multiple access (SC- FDMA) system, wireless local area network (WLAN) system, a global navigation satellites system (GNSS), and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio access technology (RAT), such as Universal Terrestrial Radio Access (UTRA), evolved UTRA (E-UTRA), CDMA 2000, etc. A TDMA network may implement a RAT, such as the Global System for Mobile Communications (GSM). An OFDMA network may implement a RAT, such as LTE or NR. A WLAN system may implement a RAT, such as Wi-Fi. The techniques described herein may be used for the wireless networks and RATs mentioned above, as well as other wireless networks and RATs.

[0028] GNSS is frequently used for positioning services in various applications, such as pedestrian and vehicular navigation. To accurately determine its position, a user equipment (UE) or station (STA) is generally equipped with a GNSS receiver. The GNSS receiver uses the time difference between the time a signal is received versus when the signal was broadcast by a satellite vehicle (SV) to determine the receiver’s distance from the SV. A GNSS receiver that receives signals from four SVs can determine its position in three dimensions (3D). Three of the SVs are used to determine latitude, longitude, and height, while a fourth SV is set to synchronize the receiver’s internal clock.

[0029] Multi-path in GNSS refers to the phenomenon when the satellite signals are reflected before reaching the GNSS receiver. Such reflections can cause significant errors in position estimation. Position estimation in an urban environment is particularly prone to inaccuracies due to multi-path. Identifying and reducing the effect of multi-path would enable GNSS to be a primary component of high integrity railway control, autonomous vehicle operating in urban environments, or a user navigating through a downtown area with skyscrapers. Many studies have been conducted on GNSS multi-path detection and mitigation. A multi-antenna system using a set of five antennas was proposed to estimate and remove multi-path error based on the spatial correlation of received signals; but this type of system is expensive and large in size, which makes it difficult to be implemented in commercial ground vehicles. A multi-path detection technique based on satellite exclusion was introduced using an upward-viewing infrared camera to identify the open sky. Satellite signals that are blocked by one or more obstacles (such as buildings), thus resulting in non-line-of-sight (NLOS) signals, were discarded when calculating position solutions. However, this approach cannot reliably detect the case when both the line-of- sight (LOS) signal and the reflected NLOS signals arrive at the GNSS receiver. FIG. 1 A illustrates a diagram 100 of a LOS signal 101 and an NLOS signal 103 received by a GNSS receiver 102. As shown in FIG. 1A, these signals are transmitted by an SV 180. The NLOS signal 103 is a multipath signal that is reflected by a reflective surface 131 of an obstacle 130. When SV 180 broadcasts signals towards the ground, multi-path signals may be received by GNSS receiver 102, for example.

[0030] FIG. IB illustrates a graphical representation 115 of a far-field multi-path scenario. Far-field multi-path may create multiple channel impulse responses, as seen in FIG. IB. To suppress the influence of far-field multi-path on the delay measurement, the LOS beam 105 at tO may be selected for use in estimating the delay functions, which may not be possible in some scenarios. For example, because the second peak at tl is stronger, some GNSS receivers may mistake the second peak as the LOS beam, which may cause position estimation error. This type of situation may occur when the direct path of LOS beam 105 is attenuated by trees and/or the second signal is a multipath signal reflected from an obstacle’s surface, for example. FIG. 1C illustrates a graphical representation 120 of a time-domain overlap and a time/frequency-domain overlap LOS and NLOS signals that may be associated with the far-field multi-path depicted in FIG. 1A. FIG. ID illustrates a graphical illustration 122 of two NLOS SVs 180-1, 180-2 blocked from view by two GNSS receivers 102-1, 102-2 by an obstacle 130.

[0031] Range redundancy checks such as receiver autonomous integrity monitoring (RAIM) may be used to detect and exclude multi-path signals in processing. However, redundancy checks are suitable for situations where there are relatively few NLOS or multi-path signals relative to overall signals. While this is an appropriate assumption for an aircraft in flight, a deep urban canyon may have as many or more multi-path and NLOS signals as compared to the number of LOS signals, such as those examples described above in connection with FIGs. 1 A-1D.

[0032] Thus, there exists an unmet need for a technique that can mitigate NLOS signals from position estimation in areas where multi-path may occur.

[0033] To overcome these and other challenges, the present disclosure provides an exemplary multi-path mitigation technique that estimates a first position of a GNSS receiver based on a set of GNSS signals. These GNSS signals may include at least one NLOS signal received from an occluded SV. In some embodiments, the LOS signal from this SV may be occluded by an obstacle. Once the first position is estimated, the GNSS receiver may obtain a 3D virtual map of an area that includes the first position. The 3D virtual map may be a map of an urban canyon, for example. Moreover, the 3D virtual map may be generated by a cloud server based on position information and SV information received from a plurality of GNSS receivers. The cloud server may generate and update the 3D virtual map based on multi-path mitigation or NLOS SVs identified by the plurality of GNSS receivers. Based on this information, the cloud server may estimate the dimensions of various obstacles, for example. Then, using the 3D virtual map, the GNSS receiver may identify at least one NLOS SV. To improve the accuracy of position estimation, the GNSS receiver may refine the first position by identifying at least one NLOS signal that was used in estimating the first position. This NLOS signal may be removed from the calculation, or the GNSS receiver may implement mirror-image geometry calculations to identify the position of the NLOS SV with a greater degree of accuracy. Examples of these techniques include, e.g., the virtual SV technique, the iterative correction technique, and/or the reliability score correction technique, as described below. Using one or more of these techniques, the GNSS receiver of the present disclosure may estimate a second position that includes a more accurate position of the GNSS receiver for navigation, for example. Finally, the GNSS receiver may send the information associated with the NLOS SV and position information to the cloud server, which may update the 3D virtual map based on this additional piece of information. Additional details associated with the GNSS receiver and cloud server of the present disclosure are provided below in connection with FIGs. 2, 3, 4, 5A, 5B, 5C, 5D, 6A, and 6B.

[0034] Although some embodiments are described herein in connection with a WLAN or GNSS communication system, the same or similar techniques may be applied to a cellular communication system, as well. For example, a UE that receives a signal from a 5G NR base station via beamforming and/or millimeter-wave (mmW) signaling may experience multi-path issues as these beams may reflect off nearby objects, which can deteriorate the accuracy of positioning determination using these signals. Thus, the techniques described below may apply to estimating a set of beam parameters for use in positioning determination by a UE in a cellular communication system without departing from the scope of the present disclosure.

[0035] As used herein, the term “pseudo-range measurement” may refer to a position estimated based on a NLOS signal. As used herein, the term “corrected pseudo-range measurement” may refer to a corrected position estimated using the exemplary multi-path mitigation technique described below. As also used herein, the terms “NLOS signal,” “multi-path signal,” and “reflected signal” may be used interchangeably.

[0036] FIG. 2 shows a simplified architecture of a wireless communication system 200 in accordance with certain embodiments presented herein. System 200 may include non-access point (AP) stations (STAs) such as UEs 220-1 through 220-w (collectively referred to as UEs 220), and AP STAs such as APs 240-1 through 240-4 (collectively referred to as APs 240), which may communicate over a wireless communication network 230. Examples of UEs 220 may include, e.g., smartphones, vehicles, wearable devices, laptops, or any other device that can provide a navigation function to a user. In some embodiments, wireless communication network 230 may take the form of and/or may include one or more wireless local area networks (WLANs) or the internet. In some embodiments, UEs 220 and/or APs 240 may communicate with server 250 via wireless communication network 230. While system 200 illustrates some UEs 220 and APs 240, the number of UEs 220 and APs 240 in a wireless communication network (e.g., a WLAN) may be varied in accordance with various system parameters. In general, system 200 may include a smaller or larger number of UEs 220 and/or APs 240.

[0037] In some embodiments, as outlined above, UE 220 may include a GNSS receiver configured to receive, measure and decode signals from one or more satellite vehicles (SVs) 280- 1 through 280-4 and thereby obtain a position fix, an accurate absolute time reference (such as global positioning system (GPS) time, Coordinated Universal Time (UTC) or a time for another GNSS which may be accurate to 50 nanoseconds (ns) or better in some embodiments) and a timing reference uncertainty. UE position information may be estimated using the GNSS signals broadcast by the SVs 280, a 3D virtual map obtained from server 250, and the use of the exemplary multi-path mitigation technique described below. The position information may be used for navigation and/or provided to APs 240, which use the information to identify a timing reference.

[0038] For example, the GNSS position fix, absolute time reference and/or absolute time synchronization information (e.g., GPS time, GNSS time, or UTC time) and timing reference uncertainty may be provided (e.g., by one or more UEs 220) to APs 240 by sending signaling information to APs 240 that includes a time reference such as using, for example, the Internet Network Time Protocol (NTP), IEEE 1588 Precision Time Protocol (PTP) and/or ITU-T Synchronous Ethernet. In some embodiments, APs 240, which receive the position fix, absolute time reference, and time reference uncertainty information, may optionally, modify the time reference uncertainty information to account for other inaccuracies and/or processing delays. In some embodiments, the absolute time and time reference uncertainty information may be modified by APs 240 based on the distance of UE 220 from AP 240, which may be determined from the position fix. For example, APs 240 may modify time reference uncertainty to adjust for Short Interframe Spacing (SIFS) delays, if appropriate. The terms “SIFS interval” or “SIFS delay” may refer to the amount of time (e.g., in microseconds) it takes for a wireless interface to process a received frame and to respond with a response frame. A SIFS interval may consist of the time delay arising from receiver radio frequency (RF) processing, Physical Layer Convergence Procedure (PLCP) delay, and the Medium Access Control (MAC) processing delay, which may depend on the physical layer used.

[0039] In some embodiments, APs 240 and/or UEs 220 that are synchronized to or have access to a common time reference may transmit or re-transmit (unicast, multicast, or broadcast) the common time reference and time reference uncertainty to other STAs or devices on network 230. For example, an AP 240 synchronized to an absolute timing reference may transmit the timing reference and timing uncertainty information to other devices. As another example, a UE 220 may demodulate the Time-Of-Week (TOW) header to obtain an absolute (e.g., GNSS) time reference. In some embodiments, UE 220 may send the absolute time reference and timing reference uncertainty to one or more APs 240. Further, the timing reference and timing uncertainty may be requested by and/or provided to one or more UEs 220 that do not have access to the absolute timing reference source.

[0040] In instances where one or more APs 240 experience clock degradation, maintaining timing synchronization by APs 240 may be facilitated by the timing information received by the APs 240 from UEs 220. In some embodiments, APs 240 may use the absolute time reference (e.g., GNSS time) for measurements and/or time stamps. For example, packets or frames sent or received by APs 240 may be timestamped using the absolute time reference. In some embodiments, multiple APs 240 on network 230 may be synchronized to a common absolute time reference (e.g., to GNSS time) via timing information received from UEs 220 to obtain a quasi-synchronous network.

[0041] In some embodiments (e.g., in quasi -synchronized networks), APs 240 may estimate one-way delay for packets received from another device based on the timestamp indicating the time the packet was sent and the time that the packet was received at AP 240. In embodiments where one or more UEs 220 may also be synchronized to the absolute time reference (bounded by the timing reference uncertainty), then, APs 240 that are also synchronized to the absolute time reference may estimate one-way delay for packets (with the timing uncertainty) received from synchronized UEs 220 based on the timestamp indicating the time the packet was sent and time that the packet was received at AP 240. Conversely, a UE 220 may also estimate one-way delay for packets received from APs 240 that are synchronized to the common absolute time reference. [0042] In some embodiments, one or more UEs 220 and/or APs 240 in system 200 may comprise multiple antennas and may support multiple-input multiple-output (MEMO) and/or multiuser MEMO (MU-MEMO). UE 220 may receive and measure signals from APs 240, which may be used for position determination. In some embodiments, APs 240 may form part of a wireless communication network 230, such as a WLAN. For example, a WLAN may be an IEEE 802.1 lx network (e.g., such as IEEE 802.1 lax, 802.1 lay, or later version). Further, system 200 may comprise or take the form of an Extended Service Set (ESS) network, which may comprise a plurality of appropriately configured basic service set (BSS) networks, an Independent Basic Service Set (IBSS) network, an ad-hoc network, or a peer-to-peer (P2P) network (e.g., operating according to Wi-Fi Direct or similar protocols).

[0043] In some embodiments, system 200 may support orthogonal frequency-division multiple access (OFDMA) communications, namely, conforming to the IEEE 802.1 lax specification or variants thereof. OFDMA may facilitate multiple STAs to transmit and receive data on a shared wireless medium at the same time. For a wireless network using OFDMA, the available frequency spectrum may be divided into a plurality of resource units (RUs) each with a number of different frequency subcarriers, and distinct RUs may be assigned (e.g., by AP 240) to various wireless devices (e.g., UEs 220) at a given point in time. Accordingly, OFDMA may facilitate the concurrent transmission of wireless data by multiple wireless devices over the wireless medium using their assigned RUs. In some implementations, an AP may use a specific type of frame (such as a “trigger frame”) to allocate specific RUs to a number of wireless devices identified in the trigger frame. The trigger frame may indicate the RU size and location, power level, and other parameters to be used by identified wireless devices for uplink (UL) transmissions. In some embodiments, the AP may also use a trigger frame to solicit uplink (UL) multi-user (MU) data transmissions from wireless devices identified in the trigger frame. In some instances, the trigger frame may indicate or specify an order for identified wireless devices are to transmit UL data to the AP.

[0044] In some embodiments, one or more UEs 220 and APs 240 may communicate over wireless communication network 230, which may be based on IEEE 802.11 or compatible standards. In some embodiments, UEs 220 and APs 240 may communicate using variants of the IEEE 802.11 standards. For example, UEs 220 and APs 240 may communicate using 802.1 lac on the 5 GHz band, which may support multiple spatial streams including MEMO and MU-MEMO and. In some embodiments, UEs 220 and APs 240 may communicate using some of the above standards, which may further support one or more of Very High Throughput (VHT) (as described in the above standards) and High Efficiency WLAN (HEW), and/or beamforming with standardized sounding and feedback mechanisms. In some embodiments, UEs 220 and or APs 240 may additionally support legacy standards for communication with legacy devices.

[0045] In some embodiments, UEs 220 and/or APs 240 may be coupled to one or more additional networks, such as a cellular carrier network, a satellite positioning network (shown in FIG. 2), wireless personal area network (WPAN) access points, and the like (not shown in FIG. 2). In some embodiments, UEs 220 and/or APs 240 may be coupled to a wireless wide area network (WWAN) (not shown in FIG. 2), A WWAN may be a Code Division Multiple Access (CDMA) network, a Time Division Multiple Access (TDMA) network, a Frequency Division Multiple Access (FDMA) network, an Orthogonal Frequency Division Multiple Access (OFDMA) network, a Single-Carrier Frequency Division Multiple Access (SC-FDMA) network, Long Term Evolution (LTE), WiMax, and so on.

[0046] A CDMA network may implement one or more radio access technologies (RATs) such as CDMA1000, Wideband-CDMA (W-CDMA), and so on. CDMA1000 includes IS-95, IS- 1000, and IS-856 standards. A TDMA network may implement Global System for Mobile Communications (GSM), Digital Advanced Mobile Phone System (D-AMPS), or some other RAT. GSM, W-CDMA, LTE, 5GNR are described in documents from 3GPP. CDMA1000 is described in documents from a consortium named “3rd Generation Partnership Project 2” (3GPP2). 3GPP and 3GPP2 documents are publicly available.

[0047] Still referring to FIG. 2, in some embodiments, any suitable node of wireless communication system 200, such as UE 220, may include a GNSS receiver. The GNSS receiver, such as GNSS receiver 402 in FIG. 4, may be configured to perform the exemplary multi-path mitigation technique for GNSS signals received from one or more SVs 280-1, 280-2, 280-3, 280- 4, etc. In some embodiments, the GNSS receiver may perform the exemplary multi-path mitigation technique by estimating a first position of a GNSS receiver based on a set of GNSS signals. These GNSS signals may include at least one NLOS signal received from an occluded SV. In some embodiments, the LOS signal from this SV may be occluded by an obstacle, such as a building. Once the first position is estimated, the GNSS receiver may obtain a 3D virtual map of an area that includes the first position from server 250.

[0048] By way of example, the 3D virtual map may be a map of an urban canyon that includes the area surrounding UE 220. Using the 3D virtual map, the GNSS receiver may identify at least one NLOS SV. To improve the accuracy of position estimation, the GNSS receiver may refine the first position by identifying at least one NLOS signal that was used in estimating the first position. This NLOS signal may be removed from the calculation, or the GNSS receiver may implement mirror-image geometry calculations to identify the position of the NLOS SV with a greater degree of accuracy. Examples of these techniques include, e.g., the virtual SV technique, the iterative correction technique, and/or the reliability score correction technique described below in connection with FIGs. 5A, 5B, 5C, 5D, 6A, and/or 6B, for example. Using these techniques, the GNSS receiver of the present disclosure may estimate a second position that may include a more accurate position of the GNSS receiver for navigation, for example. Finally, the GNSS receiver may send the information associated with the NLOS SV and position information to server 250, which may generate and/or up update the 3D virtual map based on this additional information. [0049] As illustrated in FIG. 2, UE 220 may also communicate with server 250 through wireless communication network 230. In some embodiments, UE 220 may receive location assistance (e.g., a 3D virtual map), network traffic, network load, and/or other network related information from server 250, which, in some instances, may be relayed to UEs 220 through one or more APs 240. In some embodiments, server 250 may serve as a system controller and may interface with other wireless and/or wired networks, and/or facilitate communication between devices coupled to system 200 and devices on another work. Server 250 may be a cloud server with a memory 285 and processor 290, which may be used to generate and/or update a 3D virtual map based on NLOS mitigation calculations by one or more UE 220, which each include an exemplary GNSS receiver. For instance, server 250 may use any position information, NLOS SV information, NLOS signal information, mirror-image geometry information, etc. received from UE 220 to update or generate the 3D virtual map. Using the corrected positioning information from one or more UEs 220, server 250 may generate and update the 3D virtual map based on multi-path mitigation or NLOS SVs. Moreover, in some embodiments, server 250 may generate and/orupdate the 3D virtual map based on information identified from a multi-path peak profile received from a UE 220, as described in additional detail below. Based on the various information received from UE(s) 220, server 250 may estimate and/or update the dimensions of various obstacles proximate or distal to the position of the GNSS receiver, for example. Additional details associated with the GNSS receiver (e.g., UE 220) and server 250 of the present disclosure are provided below in connection with FIGs. 4, 5 A, 5B, 5C, 5D, 6A, and 6B.

[0050] Each element in FIG. 2 may be considered a node of wireless communication system 200. More detail regarding the possible implementation of a node is provided by way of example in the description of a node 300 in FIG. 3. Node 300 may be configured as UE 220, AP 240, or server 250 in FIG. 2. As shown in FIG. 3, node 300 may include a processor 302, a memory 304, and a transceiver 306. These components are shown as connected to one another by a bus, but other connection types are also permitted. When node 300 is UE 220, additional components may also be included, such as a user interface (UI), sensors, and the like. Similarly, node 300 may be implemented as a blade in a server system when node 300 is configured as server 250. Other implementations are also possible.

[0051] Transceiver 306 may include any suitable device for sending and/or receiving data. Node 300 may include one or more transceivers, although only one transceiver 306 is shown for simplicity of illustration. An antenna 308 is shown as a possible communication mechanism for node 300. Multiple antennas and/or arrays of antennas may be utilized for receiving multiple spatially multiplex data streams. Additionally, examples of node 300 may communicate using wired techniques rather than (or in addition to) wireless techniques. For example, AP 240 may communicate wirelessly to UE 220 and may communicate by a wired connection (for example, by optical or coaxial cable) to server 250. Other communication hardware, such as a network interface card (NIC), may be included as well.

[0052] As shown in FIG. 3, node 300 may include processor 302. Although only one processor is shown, it is understood that multiple processors can be included. Processor 302 may include microprocessors, microcontroller units (MCUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout the present disclosure. Processor 302 may be a hardware device having one or more processing cores. Processor 302 may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Software can include computer instructions written in an interpreted language, a compiled language, or machine code. Other techniques for instructing hardware are also permitted under the broad category of software. [0053] As shown in FIG. 3, node 300 may also include memory 304. Although only one memory is shown, it is understood that multiple memories can be included. Memory 304 can broadly include both memory and storage. For example, memory 304 may include random-access memory (RAM), read-only memory (ROM), static RAM (SRAM), dynamic RAM (DRAM), ferroelectric RAM (FRAM), electrically erasable programmable ROM (EEPROM), compact disc read only memory (CD-ROM) or other optical disk storage, hard disk drive (HDD), such as magnetic disk storage or other magnetic storage devices, Flash drive, solid-state drive (SSD), or any other medium that can be used to carry or store desired program code in the form of instructions that can be accessed and executed by processor 302. Broadly, memory 304 may be embodied by any computer-readable medium, such as a non-transitory computer-readable medium.

[0054] Processor 302, memory 304, and transceiver 306 may be implemented in various forms in node 300 for performing wireless communication functions. In some embodiments, processor 302, memory 304, and transceiver 306 of node 300 are implemented (e.g., integrated) on one or more system-on-chips (SoCs). In one example, processor 302 and memory 304 may be integrated on an application processor (AP) SoC (sometimes known as a “host,” referred to herein as a “host chip”) that handles application processing in an operating system (OS) environment, including generating raw data to be transmitted. In another example, processor 302 and memory 304 may be integrated on a baseband processor (BP) SoC (sometimes known as a “modem,” referred to herein as a “radio”) that converts the raw data, e.g., from the host chip, to signals that can be used to modulate the carrier frequency for transmission, and vice versa, which can run a real-time operating system (RTOS). In still another example, processor 302 and transceiver 306 (and memory 304 in some cases) may be integrated on an RF SoC (sometimes known as a “transceiver,” referred to herein as a “wireless network interface”) that transmits and receives RF signals with antenna 308. It is understood that in some examples, some or all of the host chip, radio, and wireless network interface may be integrated as a single SoC. For example, a radio and a wireless network interface may be integrated into a single SoC that manages all the radio functions for GNSS communication, WLAN communication, WPAN communication, and/or cellular communication.

[0055] FIG. 4 illustrates a block diagram of an apparatus 400 including a GNSS receiver 402, a wireless network interface 404, and a host chip 406, according to some embodiments of the present disclosure. Apparatus 400 may be implemented as UE 220 of wireless communication system 200 in FIG. 2. In some embodiments, GNSS receiver 402 is implemented by processor 302 and memory 304, and wireless network interface 404 is implemented by processor 302, memory 304, and transceiver 306, as described above with respect to FIG. 3. When used for positioning determination within a WLAN communication system, GNSS receiver 402 may be implemented as a WLAN radio or communication chip. On the other hand, when used for positioning determination within a GNSS communication system, GNSS receiver 402 may be implemented as a GNSS receiver radio. Still further, when used for positioning determination within a cellular communication system, GNSS receiver 402 may be implemented as a baseband chip, and wireless network interface 404 may be implemented as an RF chip.

[0056] Besides the on-chip memory 418 (also known as “internal memory,” e.g., registers, buffers, or caches) on GNSS receiver 402, wireless network interface 404, or host chip 406, apparatus 400 may further include an external memory 408 (e.g., the system memory or main memory) that can be shared by GNSS receiver 402, wireless network interface 404, or host chip 406 through the system/main bus. Although GNSS receiver 402 is illustrated as a standalone SoC in FIG. 4, it is understood that in one example, GNSS receiver 402 and wireless network interface 404 may be integrated as one SoC; in another example, GNSS receiver 402 and host chip 406 may be integrated as one SoC; in still another example, GNSS receiver 402, wireless network interface 404, and host chip 406 may be integrated as one SoC, as described above.

[0057] In the uplink, host chip 406 may generate raw data and send it to GNSS receiver 402 for encoding, modulation, and mapping. Interface 414 of GNSS receiver 402 may receive the data from host chip 406. GNSS receiver 402 may also access the raw data generated by host chip 406 and stored in external memory 408, for example, using the direct memory access (DMA). GNSS receiver 402 may first encode (e.g., by source coding and/or channel coding) the raw data and modulate the coded data using any suitable modulation techniques, such as multi-phase shift keying (MPSK) modulation or quadrature amplitude modulation (QAM). GNSS receiver 402 may perform any other functions, such as symbol or layer mapping, to convert the raw data into a signal that can be used to modulate the carrier frequency for transmission. In the uplink, GNSS receiver 402 may send the modulated signal to wireless network interface 404 via interface 414. Wireless network interface 404, through a transmitter (TX) 450, may convert the modulated signal in the digital form into analog signals, i.e., RF signals, and perform any suitable front-end RF functions, such as filtering, digital pre-distortion, up-conversion, or sample-rate conversion. Antenna array 410 may transmit the RF signals provided by TX 450 of wireless network interface 404.

[0058] In the downlink, antenna array 410 may receive GNSS signals from one or more SVs, for example. The GNSS signals may include one or more LOS signals and/or NLOS signals. The GNSS signals may be passed to a receiver (RX) 440 of wireless network interface 404. Wireless network interface 404 may perform any suitable front-end RF functions, such as filtering, IQ imbalance compensation, down-paging conversion, or sample-rate conversion, and convert the RF signals (e.g., transmission) into low-frequency digital signals (baseband signals) that can be processed by GNSS receiver 402.

[0059] As seen in FIG. 4, GNSS receiver 402 may include navigation circuit 420 configured to perform position estimation using any of the multi-path mitigation techniques and/or computations described herein. For example, navigation circuit 420 may perform the NLOS mitigation technique by estimating a first position of apparatus 400 based on a set of GNSS signals. These GNSS signals may include at least one NLOS signal received from an occluded SV. In some embodiments, the LOS signal from this SV may be occluded by an obstacle. Once the first position is estimated, navigation circuit 420 may obtain a 3D virtual map of an area that includes the first position from a cloud server, such as server 250. The 3D virtual map may be a map of an urban canyon, for example. Moreover, the 3D virtual map may be generated by the cloud server based on position information and SV information received from a plurality of GNSS receivers of various apparatuses. The cloud server may generate and update the 3D virtual map based on multipath mitigation or NLOS SVs identified by the plurality of GNSS receivers. Based on this information, server 250 may estimate the dimensions of various obstacles proximate or distal to the position of the GNSS receiver, for example.

[0060] Using the 3D virtual map, navigation circuit 420 may identify at least one NLOS SV. To improve the accuracy of position estimation, navigation circuit 420 may then refine the first position by identifying at least one NLOS signal that was used in estimating the first position. This NLOS signal may be removed from the calculation, or navigation circuit 420 may implement mirror-image geometry calculations to identify the position of the NLOS SV with a greater degree of accuracy. Examples of these techniques include, e.g., the virtual SV technique, the iterative correction technique, and/or the reliability score correction technique described below in connection with FIGs. 5A, 5B, 5C, 5D, 6A, and 6B, for example. Using these techniques, navigation circuit 420 of the present disclosure may estimate a second position that may include a more accurate position of apparatus 400 for navigation, for example. Finally, apparatus 400 may send the information associated with the NLOS SV and position information to the cloud server, which may generate and/or up update the 3D virtual map based on this additional information. Additional details associated with operations performed GNSS receiver 402 and/or navigation circuit 420 are provided below in connection with FIGs. 5 A, 5B, 5C, 5D, 6 A, and 6B.

[0061] FIG. 5A illustrates a diagram of a multi-path scenario 500 in which the exemplary multi-path mitigation technique may be applied by a GNSS receiver, according to some embodiments of the present disclosure. FIG. 5B illustrates a diagram of SV mirror-image geometry 515 that may be used by the GNSS receiver to perform the exemplary multi-path mitigation technique associated with the multi-path scenario depicted in FIG. 5A, according to some embodiments of the present disclosure. FIG. 5C illustrates a diagram of GNSS mirror-image geometry 525 that may be used by the GNSS receiver to perform the exemplary multi-path mitigation technique associated with the multi-path scenario depicted in FIG. 5A, according to some embodiments of the present disclosure. FIG. 5D illustrates a diagram 535 of estimating a position of an NLOS SV based on the GNSS mirror-image geometry of FIG. 5C, according to some embodiments of the present disclosure. FIGs. 5A-5D will be described together.

[0062] Referring to FIG. 5A, UE 220 that includes GNSS receiver 402 is depicted within an urban canyon, which includes a first obstacle 530-1 and a second obstacle 530-2, by way of example. In the present example, SV 280-k transmits various GNSS signals, e.g., via broadcasting. The LOS signal 501 is blocked by first obstacle 530-1. UE 220 receives the NLOS signal 503 (e.g., a multi-path signal) that reflects off reflective surface 531 of second obstacle 530-2. To implement the multi-path mitigation technique, the navigation circuit 420 at UE 220 may estimate a first position of UE 220 based on the NLOS signal 503 and one or more other GNSS signals (not shown) from other SVs, either LOS or NLOS. Then, navigation circuit 420 may obtain a 3D virtual map from a cloud server, such as server 250 in FIG. 2. The 3D virtual map may include information associated with the dimensions of obstacles 530-1 and 530-2, for example. Moreover, the 3D virtual map may include information associated with the location of NLOS SV 280-k. Thus, based on this information, navigation circuit 420 may determine that the number of LOS SVs (not shown) is less than four. Thus, navigation circuit 420 may implement the multi-path mitigation technique to correct the NLOS pseudo-range measurement associated with NLOS signal 503 to correct for position estimation inaccuracies. For example, the multi-path mitigation technique may include, among others, the virtual SV technique, the iterative correction technique, and/or the reliability score correction technique described below in connection with FIGs. 5B-5D.

[0063] Referring to FIG. 5B, navigation circuit 420 may estimate the first position R ( RX> yRX> ^zRX’ Rx which includes position in 3D and timing, by resolving the navigation function shown below in expression (1):

where (x_k, y_k, z_k, t_k~) may include the location and timing of SV 280-k. [0064] Thus, navigation circuit 420 may estimate the first position (XRX, ysx, ZRX, IRX) based on expression (2):

[0065] Then, based on the information provided by the 3D virtual map, navigation circuit 420 may mitigate the influence of the pseudo-range measurement (which may be a distance or position measured using one or more multi-path signals) associated with NLOS signal 503 by replacing the navigation function shown above in expression (1) using mirror-image geometry computed for SV mirror 280-kM based on information associated with reflective surface 531 and second obstacle 530-2. For example, the location (xk,M, yk,M, Zk,M, tk) of SV mirror 280-kM may be computed based on expression (3):

= Mirror(ReflectiveSurface, (x_k, y_k, z_k, t_k)) (3).

[0066] Then, assuming k is equal to 2, the corrected navigation equation computed by navigation circuit 420 may be described according to expression (4):

( RX> RX’ ZRX> tRx) —

where (XRX, RX, ZRX, £RX) in expression (4) is the second position estimated for UE 220.

[0067] Referring to FIG. 5C, for the iterative correction technique, navigation circuit 420 may estimate the first position based on previous iterations of position estimation and/or based on other location services such as Wi-Fi AP access or serving cell identification for cellular services. [0068] Then, based on the 3D virtual map, navigation circuit 420 may insert corrective measurements associated with the distance between UE 220 and SV 280-k based on mirror-image geometry associated with UE 220, as shown in FIG. 5C.

[0069] For example, assuming that(x, y, z)/ is the first position of UE 220 estimated after iteration /, from knowledge of this first position, navigation circuit 420 identify the location of the mirror-image UE 220-M as ( _M,y_M, z_M) . Referring to FIG. 5D, from measured distance R navigation circuit 420 may identify the distance to SV 280-k as R according to expression (5):

where a is an angle determined based the position of mirror-image UE 220-M, and P is an angle determined based on the position of UE 220.

[0070] Referring again to FIG. 5C, navigation circuit 420 may use the reliability score correction technique to perform multi-path mitigation. For example, assume that from other SVs (not shown), navigation circuit 420 estimates the first position as (x,y, z). Here, navigation circuit 420 may use the measurement from NLOS SV 280-k to verify the reliability of these measurement based on the location (XM, yM, ZM) of mirror-image UE 220-M (shown in FIG. 5C) based on the 3D virtual map.

[0071] Then, from mirror location ( _M, y_M, z_M), navigation circuit 420 may estimate the distance R between SV 280-k and UE 220 using expression (6):

R = 7 (x_k - x_M + (y_k - y_M)² + (z_k - z_M)² (6).

[0072] From the initial position measurement of R (first position) and the distance estimation of R (second position), navigation circuit 420 may generate a reliability score to evaluate the accuracy of the second position according to expression (7):

[0073] Navigation circuit 420 may use the score computed using expression (7) to select SV combinations to use in estimating the second position R with a higher degree of accuracy, for example. According to expression (7), if the reliability score is small, this may indicate that the current location estimation has a desirable degree of accuracy. If more than four SVs 280 are available for GNSS positioning, navigation circuit 420 may select different sets of SVs 280 to evaluate the reliability score for the various combinations. Then, navigation circuit 420 may select the set of SVs 280 that yields the smallest reliability score for use in final position estimation. While expression (7) is given as one example for evaluating the reliability of the position estimation, the computation of the reliability score is not limited thereto. Rather, any statistical evaluation for the reliability of a measurement may be used without departing from the scope of the present disclosure.

[0074] Referring again to FIGs. 2 and 4, GNSS receiver 402 may send to server 250 one or more of the initial position measurement R, subsequent position estimation R after multi-path correction, mirror-image geometry information, information related to the multi-path peak profile, and/or speed at which the GNSS receiver 402 is moving. Server 250 may use this information to generate and/or update a 3D virtual map of the area surrounding GNSS receiver 402.

[0075] In some embodiments, server 250 may identify an obstacle’s relative position with respect to one or more of SVs 280 based at least in part on a NLOS peak of a multi-path peak profile. For example, when the first peak of the multi-path peak profile is identified as a LOS peak and a second peak of lower power is identified as a NLOS peak, this may indicate to server 250 that an obstacle is positioned behind UE 220 and causing a reflected NLOS signal. The NLOS signal may be received GNSS receiver 402 with reduced power as compared to the LOS signal. If the 3D virtual map includes a position and/or dimensions for obstacle 530 that would not indicate GNSS receiver 402 should receive a NLOS signal or receive the NLOS signal at a different time or signal strength, e.g., server 250 may update and/or refine the dimensions of this obstacle 530 based on the NLOS signal of the multi-path peak profile. The position/dimensions of the obstacle in the 3D virtual map may be updated such that the time and strength of the NLOS signal calculated by server 250 (based on the relative positions of GNSS receiver 402 and the SVs 280) corresponds that the time and strength of the NLOS signal observed by GNSS receiver 402. In this way, server 250 may update the position/dimensions of obstacles in 3D virtual map based on various factors to increase the accuracy of the information included in the map.

[0076] In some embodiments, server 250 may update the position/dimensions of obstacles in the 3D virtual map based on Doppler shift information identified from a multi-path peak profile associated with a GNSS receiver 402 in motion. Server 250 may identify Doppler shift information when the frequency of the signals received by GNSS receiver 402 are different than the frequency of the signals broadcast by an SV 280. Server 250 may use the Doppler shift information to estimate the position/dimensions of an obstacle 530 associated with a NLOS signal. For example, server 250 may compute the frequency of the NLOS signal including the Doppler shift based on a position/dimension of the obstacle from the 3D virtual map. If the computed frequency is different than the frequency observed in the multi-path peak profile, server 250 may update the position/dimensions of the obstacle in the 3D virtual map based on the observed frequency of the NLOS signal. Here again, by updating the information in the 3D virtual map based on Doppler shift information in a multi-path peak profile, server 250 may increase the accuracy of the features included in the 3D virtual map.

[0077] FIG. 6A illustrates a flowchart of an exemplary method 600 of wireless communication, according to embodiments of the disclosure. Exemplary method 600 may be performed by GNSS receiver, e.g., such as UE 220, apparatus 400, GNSS receiver 402, navigation circuit 420, and/or node 300. Method 600 may include steps 602-608 as described below. It is to be appreciated that some of the steps may be optional, and some of the steps may be performed simultaneously, or in a different order than shown in FIG. 6A.

[0078] At 602, the GNSS receiver may estimate a first position based on one or more GNSS signals associated with a plurality of SVs. For example, referring to FIG. 5B, navigation circuit 420 may estimate the first position x_RX, y_RX, z_RX, t_RX), which includes position in 3D and timing, by resolving the navigation function shown above in expression (1).

[0079] At 604, the GNSS receiver may obtain a virtual map associated with the first position. For example, referring to FIGs. 2 and 5 A, UE 220 may obtain a 3D virtual map from server 250.

[0080] At 606, the GNSS receiver may identify an NLOS SV based on the first position and 3D virtual map. For example, referring to FIGs. 5A-5D, navigation circuit 420 may obtain a 3D virtual map from a cloud server, such as server 250 in FIG. 2. The 3D virtual map may include information associated with the dimensions of obstacles 530-1 and 530-2, for example. Moreover, the 3D virtual map may include information associated with the location of NLOS SV 280-k. Thus, based on this information, navigation circuit 420 may determine that that the number of LOS SVs (not shown) is less than four. Thus, navigation circuit 420 may implement the multi-path mitigation technique to correct the NLOS pseudo-range measurement associated with NLOS signal 503 to correct for position estimation inaccuracies.

[0081] At 608, the GNSS receiver may estimate a second position by correcting pseudorange measurement used to estimate the first position. For example, referring to FIGs. 5A-5D, navigation circuit 420 may implement the virtual satellite technique, the iterative correction technique, and/or the reliability score correction technique described above to estimate the second position.

[0082] FIG. 6B illustrates a flowchart of an exemplary method 610 of generating a 3D virtual map, according to embodiments of the disclosure. Exemplary method 610 may be performed by a cloud server, e.g., such as server 250 and/or node 300. Method 610 may include steps 612 and 614 as described below. It is to be appreciated that some of the steps may be optional, and some of the steps may be performed simultaneously, or in a different order than shown in FIG. 6B.

[0083] At 612, the cloud server may receive position information from a plurality of GNSS receivers. The position information may include GNSS receiver information (GNSS position information, first position, second position, etc.) and SV information. The SV information includes a plurality of multi-path profiles associated with a plurality of SVs that are determined by a GNSS receiver during the exemplary multi-path mitigation technique described above. For example, referring to FIG. 2, server 250 may receive position information from a plurality of UEs 220, each equipped with a GNSS receiver.

[0084] At 614, the cloud server may generate a 3D virtual map based on the GNSS receiver information and SV information. The 3D virtual map may include a plurality of obstacles. The 3D virtual map may be generated by estimating various dimensions of obstacles based on the NLOS profiles determined by the GNSS receivers during the multi-path mitigation technique used for position estimation. For example, referring to FIGs. 2 and 4, GNSS receiver 402 may send one or more of the initial position measurement R, position estimation R after multi-path correction, mirror-image geometry information, information related to the multi-path peak profile, and/or motion information to server 250. Server 250 may use this information to generate and/or update a 3D virtual map of the area surrounding GNSS receiver 402. In some embodiments, server 250 may identify an obstacle’s relative position with respect to one or more of SVs 280 based at least in part on a NLOS peak of a multi-path peak profile. For example, when the first peak of the multipath peak profile is identified as a LOS peak and a second peak of lower power is identified as a NLOS peak, this may indicate to server 250 that an obstacle is positioned behind UE 220. Here, obstacle 530 may cause a NLOS signal by reflecting a signal broadcast by an SV 280. The NLOS signal may be received GNSS receiver 402 with reduced power as compared to the LOS signal. If the 3D virtual map includes a position and/or dimensions for obstacle 530 that would not indicate GNSS receiver 402 should receive a NLOS signal or receive the NLOS signal at a different time or signal strength, e.g., server 250 may update and/or refine the dimensions of this obstacle 530 based on the NLOS signal of the multi-path peak profile. The position/dimensions of the obstacle in the 3D virtual map may be updated such that the time and strength of the NLOS signal calculated by server 250 based on the relative positions of GNSS receiver 402 and the SVs 280 corresponds that the time and strength of the NLOS signal observed by GNSS receiver 402. In this way, server 250 may continually update the position/dimensions of obstacles in 3D virtual map based on various factors to increase the accuracy of the information included in the map. In some embodiments, server 250 may update the position/dimensions of obstacles in the 3D virtual map based on Doppler shift information identified from a multi-path peak profile associated with a GNSS receiver 402 in motion. Server 250 may identify Doppler shift information when the frequency of the signals received by GNSS receiver 402 are different than the frequency of the signals broadcast by an SV 280. Server 250 may use the Doppler shift information to estimate the position/dimensions of an obstacle 530 associated with a NLOS signal. For example, server 250 may compute the frequency of the NLOS signal including the Doppler shift based on a position/dimension of the obstacle from the 3D virtual map. If the computed frequency is different than the frequency observed in the multi-path peak profile, server 250 may update the position/dimensions of the obstacle in the 3D virtual map based on the observed frequency of the NLOS signal. Here again, by updating the information in the 3D virtual map based on Doppler shift information in a multi-path peak profile, server 250 may increase the accuracy of the 3D virtual map.

[0085] In various aspects of the present disclosure, the functions described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or encoded as instructions or code on a non-transitory computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computing device, such as node 300 in FIG. 5. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, HDD, such as magnetic disk storage or other magnetic storage devices, Flash drive, SSD, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a processing system, such as a mobile device or a computer. Disk and disc, as used herein, includes CD, laser disc, optical disc, digital video disc (DVD), and floppy disk where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. [0086] According to one aspect of the present disclosure, a GNSS receiver is provided. The GNSS receiver may include a navigation circuit. The navigation circuit may be configured to estimate a first position associated with the GNSS receiver based on one or more GNSS signals associated with a first plurality of SVs. The navigation circuit may be configured to obtain a 3D virtual map associated with the first position. The navigation circuit may be configured to identify an NLOS SV based on the first position and the 3D virtual map. The navigation circuit may be configured to estimate a second position associated with the GNSS receiver by correcting a pseudorange measurement associated with the NLOS SV and used to estimate the first position.

[0087] In some embodiments, the navigation circuit may be configured to receive the one or more GNSS signals associated with the first plurality of SVs.

[0088] In some embodiments, the one or more GNSS signals may include at least one NLOS signal associated with the NLOS SV.

[0089] In some embodiments, the at least one NLOS signal may be associated with the pseudo-range measurement used to estimate the first position.

[0090] In some embodiments, the 3D virtual map may be obtained from a remote server.

[0091] In some embodiments, the navigation circuit may be configured to identify at least one obstacle associated with the first position based on the 3D virtual map.

[0092] In some embodiments, the NLOS SV may be identified based on the at least one obstacle.

[0093] In some embodiments, the first position may be estimated based on a set of navigation functions associated with the first plurality of SVs. In some embodiments, the set of navigation functions may include the pseudo-range measurement of the NLOS SV.

[0094] In some embodiments, the navigation circuit may be configured to estimate the second position by estimating mirror-image geometry associated with the NLOS SV and a reflective surface identified in the 3D virtual map. In some embodiments, the navigation circuit may be configured to estimate the second position by replacing the pseudo-range measurement in the set of navigation functions with the mirror-image geometry associated with the NLOS SV.

[0095] In some embodiments, the navigation circuit may be configured to estimate the second position by estimating mirror-image geometry associated with the GNSS receiver and a reflective surface identified in the 3D virtual map. In some embodiments, the navigation circuit may be configured to estimate the second position by estimating a first distance associated with the NLOS SV based on the mirror-image geometry associated with the GNSS receiver. In some embodiments, the navigation circuit may be configured to estimate the second position by estimating a second distance from the NLOS SV to the GNSS receiver based on the first distance. In some embodiments, the second distance from the NLOS SV to the GNSS receiver may be used to estimate the second position.

[0096] In some embodiments, the navigation circuit may be configured to estimate the second position by computing a reliability score associated with at least one LOS SV based on the first position and the second distance from the NLOS SV to the GNSS receiver. In some embodiments, the navigation circuit may be configured to estimate the second position by selecting a second plurality of SVs based on the reliability score, the second plurality of SVs being different than the first plurality of SVs. In some embodiments, the navigation circuit may be configured to estimate the second position by estimating the second position based on the second plurality of SVs.

[0097] According to another aspect of the disclosure, a cloud server is provided. The cloud server may include at least one processor. The cloud server may include memory storing instruction that, when executed by the at least one processor, causes the cloud server at least to receive position information from a plurality of GNSS receivers. The position information may include GNSS receiver information and SV information. The SV information includes a plurality of multi-path profiles associated with a plurality of SVs. The cloud server may include memory storing instruction that, when executed by the at least one processor, generate a 3D virtual map based on the GNSS receiver information and the SV information. The position information may include one or more pseudo-range measurements corrected by at least one GNSS receiver.

[0098] In some embodiments, the 3D virtual map may include a plurality of obstacles.

[0099] In some embodiments, the memory storing instruction that, when executed by the at least one processor, cause the cloud server to generate the 3D virtual map by estimating one or more dimensions for each of the plurality of obstacles based at least in part on the multi-path profiles associated with the plurality of SVs.

[0100] In some embodiments, the memory storing instruction that, when executed by the at least one processor, may cause the cloud server to generate the 3D virtual map by identifying a relative position of an obstacle with respect to one or more of the plurality of SVs based at least in part on a second peak of multi-path peak profile with power below a threshold. In some embodiments, the memory storing instruction that, when executed by the at least one processor, may cause the cloud server to generate the 3D virtual map by updating the 3D virtual map based on the relative position of the obstacle identified based on the NLOS peak of the multi-path peak profile In some embodiments, the multi-path peak profile may be associated with the position information.

[0101] In some embodiments, the memory storing instruction that, when executed by the at least one processor, may cause the cloud server to generate the 3D virtual map by identifying Doppler shift information from a multi-path peak profile associated with the position information. In some embodiments, the memory storing instruction that, when executed by the at least one processor, may cause the cloud server to generate the 3D virtual map by estimating a location of an obstacle based at least in part on the Doppler shift information identified from the multi-path peak profile. In some embodiments, the memory storing instruction that, when executed by the at least one processor, may cause the cloud server to generate the 3D virtual map by updating the 3D virtual map based on the location of the obstacle estimated based at least in part on the Doppler shift information.

[0102] According to yet another aspect of the disclosure, a method of wireless communication of a GNSS receiver is provided. The method may include estimating, by a navigation circuit, a first position associated with the GNSS receiver based on one or more GNSS signals associated with a first plurality of SVs. The method may include obtaining, by the navigation circuit, a 3D virtual map associated with the first position. The method may include identifying, by the navigation circuit, an NLOS SV based on the first position and the 3D virtual map. The method may include estimating, by the navigation circuit, a second position associated with the GNSS receiver by correcting a pseudo-range measurement associated with the NLOS SV and used to estimate the first position.

[0103] In some embodiments, the method may include receiving, by the navigation circuit, the one or more GNSS signals associated with the first plurality of SVs.

[0104] In some embodiments, the one or more GNSS signals may include at least one NLOS signal associated with the NLOS SV.

[0105] In some embodiments, the at least one NLOS signal may be associated with the pseudo-range measurement used to estimate the first position.

[0106] In some embodiments, the 3D virtual map may be obtained from a remote server.

[0107] In some embodiments, the method may include identifying, by the navigation circuit, at least one obstacle associated with the first position based on the 3D virtual map.

[0108] In some embodiments, the NLOS SV may be identified based on the at least one obstacle.

[0109] In some embodiments, the first position may be estimated based on a set of navigation functions associated with the first plurality of SVs. In some embodiments, the set of navigation functions may include the pseudo-range measurement of the NLOS SV.

[0110] In some embodiments, the estimating the second position may include estimating, by the navigation circuit, mirror-image geometry associated with the NLOS SV and a reflective surface identified in the 3D virtual map. In some embodiments, the estimating the second position may include replacing, by the navigation circuit, the pseudo-range measurement in the set of navigation functions with the mirror-image geometry associated with the NLOS SV.

[OHl] In some embodiments, the estimating the second position may include estimating, by the navigation circuit, mirror-image geometry associated with the GNSS receiver and a reflective surface identified in the 3D virtual map. In some embodiments, the estimating the second position may include estimating, by the navigation circuit, a first distance associated with the NLOS SV based on the mirror-image geometry associated with the GNSS receiver. In some embodiments, the estimating the second position may include estimating, by the navigation circuit, a second distance from the NLOS SV to the GNSS receiver based on the first distance. In some embodiments, the second distance from the NLOS SV to the GNSS receiver may be used to estimate the second position.

[0112] In some embodiments, the estimating the second position may include computing, by the navigation circuit, a reliability score associated with at least one LOS SV based on the first position and the second distance from the NLOS SV to the GNSS receiver. In some embodiments, the estimating the second position may include selecting, by the navigation circuit, a second plurality of SVs based on the reliability score, the second plurality of SVs being different than the first plurality of SVs. In some embodiments, the estimating the second position may include estimating, by the navigation circuit, the second position based on the second plurality of SVs.

[0113] According to still another aspect of the disclosure, a method of a server device is provided. The method may include receiving, by a processor, position information from a plurality of GNSS receivers. The position information including GNSS receiver information and SV information. The SV information includes a plurality of multi-path profiles associated with a plurality of SVs. The method may include generating, by the processor, a 3D virtual map based on the GNSS receiver information and the SV information.

[0114] In some embodiments, the 3D virtual map may include a plurality of obstacles. In some embodiments, the generating the 3D virtual map may include estimating one or more dimensions for each of the plurality of obstacles based at least in part on the multi-path profiles associated with the plurality of SVs.

[0115] The foregoing description of the specific embodiments will so reveal the general nature of the present disclosure that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance.

[0116] Embodiments of the present disclosure have been described above with the aid of functional obstacle blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional obstacle blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.

[0117] The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present disclosure as contemplated by the inventor(s), and thus, are not intended to limit the present disclosure and the appended claims in any way.

[0118] Various functional blocks, modules, and steps are disclosed above. The particular arrangements provided are illustrative and without limitation. Accordingly, the functional blocks, modules, and steps may be re-ordered or combined in different ways than in the examples provided above. Likewise, certain embodiments include only a subset of the functional blocks, modules, and steps, and any such subset is permitted.

[0119] The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

- 29 - WHAT IS CLAIMED IS:

1. A global navigation satellite system (GNSS) receiver, comprising: a navigation circuit configured to: estimate a first position associated with the GNSS receiver based on one or more GNSS signals associated with a first plurality of satellite vehicles (SVs); obtain a three-dimensional (3D) virtual map associated with the first position; identify a non-line-of-sight (NLOS) satellite vehicle (SV) based on the first position and the 3D virtual map; and estimate a second position associated with the GNSS receiver by correcting a pseudo-range measurement associated with the NLOS SV and used to estimate the first position.

2. The GNSS receiver of claim 1, wherein the navigation circuit is configured to: receive the one or more GNSS signals associated with the first plurality of SVs, wherein the one or more GNSS signals include at least one NLOS signal associated with the NLOS SV.

3. The GNSS receiver of claim 2, wherein the at least one NLOS signal is associated with the pseudo-range measurement used to estimate the first position.

4. The GNSS receiver of claim 1, wherein the 3D virtual map is obtained from a remote server.

5. The GNSS receiver of claim 4, wherein the navigation circuit is further configured to: identify at least one obstacle associated with the first position based on the 3D virtual map, wherein the NLOS SV is identified based on the at least one obstacle.

6. The GNSS receiver of claim 1, wherein: the first position is estimated based on a set of navigation functions associated with the first plurality of SVs, and the set of navigation functions includes the pseudo-range measurement of the NLOS SV.

7. The GNSS receiver of claim 6, wherein the navigation circuit is configured to estimate the - 30 - second position by: estimating mirror-image geometry associated with the NLOS SV and a reflective surface identified in the 3D virtual map; and replacing the pseudo-range measurement in the set of navigation functions with the mirrorimage geometry associated with the NLOS SV.

8. The GNSS receiver of claim 1, wherein the navigation circuit is configured to estimate the second position by: estimating mirror-image geometry associated with the GNSS receiver and a reflective surface identified in the 3D virtual map; estimating a first distance associated with the NLOS SV based on the mirror-image geometry associated with the GNSS receiver; and estimating a second distance from the NLOS SV to the GNSS receiver based on the first distance, wherein the second distance from the NLOS SV to the GNSS receiver is used to estimate the second position.

9. The GNSS receiver of claim 8, wherein the navigation circuit is configured to estimate the second position by: computing a reliability score associated with at least one line-of-sight (LOS) SV based on the first position and the second distance from the NLOS SV to the GNSS receiver; selecting a second plurality of SVs based on the reliability score, the second plurality of SVs being different than the first plurality of SVs; and estimating the second position based on the second plurality of SVs.

10. A cloud server, comprising: at least one processor; and memory storing instruction that, when executed by the at least one processor, causes the cloud server at least to: receive position information from a plurality of global navigation satellite system (GNSS) receivers, the position information including GNSS receiver information and satellite vehicle (SV) information, the SV information including a plurality of multi-path profiles associated with a plurality of satellite vehicles (SVs); and generate a three-dimensional (3D) virtual map based on the GNSS receiver information and the SV information, wherein the position information is associated with one or more pseudorange measurements corrected by at least one GNSS receiver.

11. The cloud server of claim 10, wherein the 3D virtual map includes a plurality of obstacles, and wherein the memory storing instruction that, when executed by the at least one processor, cause the cloud server to generate the 3D virtual map by: estimating one or more dimensions for each of the plurality of obstacles based at least in part on the multi-path profiles associated with the plurality of SVs.

12. The cloud server of claim 10, wherein the memory storing instruction that, when executed by the at least one processor, cause the cloud server to generate the 3D virtual map by: identifying a relative position of an obstacle with respect to one or more of the plurality of SVs based at least in part on a non-line-of-sight (NLOS) peak of a multi-path peak profile; and updating the 3D virtual map based on the relative position of the obstacle identified based on the NLOS peak of the multi-path peak profile, wherein the multi-path peak profile is associated with the position information.

13. The cloud server of claim 10, wherein the memory storing instruction that, when executed by the at least one processor, cause the cloud server to generate the 3D virtual map by: identifying Doppler shift information from a multi-path peak profile associated with the position information; estimating a location of an obstacle based at least in part on the Doppler shift information identified from the multi-path peak profile; and updating the 3D virtual map based on the location of the obstacle estimated based at least in part on the Doppler shift information.

14. A method of wireless communication of a global navigation satellite system (GNSS) receiver, comprising: estimating, by a navigation circuit, a first position associated with the GNSS receiver based on one or more GNSS signals associated with a first plurality of satellite vehicles (SVs); obtaining, by the navigation circuit, a three-dimensional (3D) virtual map associated with the first position; identifying, by the navigation circuit, a non-line-of-sight (NLOS) satellite vehicle (SV) based on the first position and the 3D virtual map; and estimating, by the navigation circuit, a second position associated with the GNSS receiver by correcting a pseudo-range measurement associated with the NLOS SV and used to estimate the first position.

15. The method of claim 14, further comprising: receiving, by the navigation circuit, the one or more GNSS signals associated with the first plurality of SVs, wherein the one or more GNSS signals include at least one NLOS signal associated with the NLOS SV, wherein the at least one NLOS signal is associated with the pseudo-range measurement used to estimate the first position, and wherein the 3D virtual map is obtained from a remote server.

16. The method of claim 15, further comprising identifying, by the navigation circuit, at least one obstacle associated with the first position based on the 3D virtual map.

17. The method of claim 16, wherein the NLOS SV is identified based on the at least one obstacle.

18. The method of claim 14, wherein: the first position is estimated based on a set of navigation functions associated with the first plurality of SVs, and the set of navigation functions includes the pseudo-range measurement of the NLOS SV.

19. The method of claim 18, wherein the estimating the second position comprises: estimating, by the navigation circuit, mirror-image geometry associated with the NLOS SV - 33 - and a reflective surface identified in the 3D virtual map; and replacing, by the navigation circuit, the pseudo-range measurement in the set of navigation functions with the mirror-image geometry associated with the NLOS SV.

20. The method of claim 14, wherein the estimating the second position comprises: estimating, by the navigation circuit, mirror-image geometry associated with the GNSS receiver and a reflective surface identified in the 3D virtual map; estimating, by the navigation circuit, a first distance associated with the NLOS SV based on the mirror-image geometry associated with the GNSS receiver; and estimating, by the navigation circuit, a second distance from the NLOS SV to the GNSS receiver based on the first distance, wherein the second distance from the NLOS SV to the GNSS receiver is used to estimate the second position; computing, by the navigation circuit, a reliability score associated with at least one line-of- sight (LOS) SV based on the first position and the second distance from the NLOS SV to the GNSS receiver; selecting, by the navigation circuit, a second plurality of SVs based on the reliability score, the second plurality of SVs being different than the first plurality of SVs; and estimating, by the navigation circuit, the second position based on the second plurality of

SVs.