Precise Point Positioning (PPP) based Real Time Kinematic (RTK) correction

Abstract

A device may use precise point positioning (PPP) correction information to generate real-time kinematic (RTK) correction information that can be sent to other devices for RTK-based positioning. In particular, according to some embodiments, a first device having access to the PPP correction information may obtain the PPP correction information, determine a virtual RTK base station location, and generate the RTK correction information by generating a virtual multi-satellite constellation multi-frequency (MCMF) measurement corresponding to the determined virtual RTK base station location based on the PPP correction information. This virtual MCMF measurement (and / or data derived therefrom) may then be sent to the other device as the RTK correction information.

Description

Technical Field

[0001] The present disclosure generally relates to the field of satellite-based positioning.

Background Art

[0002] Global Navigation Satellite Systems (GNSS) positioning of mobile devices (e.g., household electronics, vehicles, assets, drones, etc.) can provide accurate positioning of mobile devices equipped with GNSS receivers. Conventional GNSS positioning provides accuracy on the order of several meters, and more precise GNSS-based techniques can provide accuracy of less than one meter. Precise Point Positioning (PPP) and Real Time Kinematic (RTK) are two types of GNSS-based positioning techniques that provide higher precision. Both techniques use additional correction information to achieve higher precision than conventional GNSS positioning, but this additional correction information is not always available. Furthermore, GNSS receivers capable of RTK positioning but not PPP positioning cannot achieve higher positioning precision when only PPP correction information is available.

Summary of the Invention

[0003] The embodiments described in this specification enable a device to generate RTK correction information that can be sent to other devices for RTK-based positioning using PPP correction information. In particular, according to some embodiments, a first device having access to PPP correction information may obtain the PPP correction information, determine a virtual RTK base station location, and generate RTK correction information by generating virtual multi-constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location based on the PPP correction information. This virtual MCMF measurement (and / or data derived therefrom) can then be sent to other devices as RTK correction information.

[0004] An exemplary method for providing real-time kinematic (RTK) correction information for global navigation satellite system (GNSS)-based positioning according to the present disclosure may include obtaining precise point positioning (PPP) correction information at a first device. The method may also include determining a virtual RTK base station location. The method may also include generating virtual multi-constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location and at least partially based on the PPP correction information. The method may also include transmitting, by the first device, RTK correction information at least partially based on the virtual MCMF measurements.

[0005] An exemplary device for providing real-time kinematic (RTK) correction information for global navigation satellite system (GNSS)-based positioning according to the present disclosure may include a transceiver, a memory, and one or more processors communicatively coupled to the transceiver and the memory, and the one or more processors may be configured to obtain precise point positioning (PPP) correction information. The one or more processors may be further configured to determine a virtual RTK base station location. The one or more processors may be further configured to generate virtual multi-constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location and based at least in part on the PPP correction information. The one or more processors may be further configured to transmit, via the transceiver, RTK correction information based at least in part on the virtual MCMF measurements by the device.

[0006] An exemplary apparatus for providing real-time kinematic (RTK) correction information for global navigation satellite system (GNSS)-based positioning according to the present disclosure may include means for obtaining precise point positioning (PPP) correction information in the apparatus. The apparatus may further include means for determining a virtual RTK base station location. The apparatus may further include means for generating virtual multi-constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location and based at least in part on the PPP correction information. The apparatus may further include means for transmitting RTK correction information based at least in part on the virtual MCMF measurements by the apparatus.

[0007] According to the present disclosure, an exemplary non-transitory computer-readable medium stores instructions for providing real-time kinematic (RTK) correction information for global navigation satellite system (GNSS)-based positioning, the instructions including code for obtaining precise point positioning (PPP) correction information at a first device. The instructions may further include code for determining a virtual RTK base station location. The instructions may further include code for generating virtual multi-constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location and at least partially based on the PPP correction information. The instructions may further include code for transmitting RTK correction information at least partially based on the virtual MCMF measurements by the first device.

[0008] This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used alone to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification of this disclosure, any or all of the drawings, and the appropriate portions of each claim. The above, together with other features and examples, will be described in more detail below in the following specification, claims, and attached drawings.

Brief Description of the Drawings

[0009]

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[0010] According to some exemplary implementations, like reference numerals in the various drawings indicate like elements. Additionally, multiple instances of an element may be indicated by following the first digit of that element with a letter or a hyphen and a second digit. For example, multiple instances of element 110 may be indicated as 110-1, 110-2, 110-3, etc., or as 110a, 110b, 110c, etc. When referring to such an element using only the first digit, any instance of that element should be understood (e.g., element 110 in the previous example refers to elements 110-1, 110-2, and 110-3, or elements 110a, 110b, and 110c).

Embodiments for Carrying Out the Invention

[0011] Here, with respect to the accompanying drawings that form a part of this specification, some exemplary embodiments are described. Specific embodiments in which one or more aspects of the present disclosure may be implemented are described below, but other embodiments may be used and various modifications may be made without departing from the scope of the present disclosure or the spirit of the appended claims.

[0012] As described herein, a satellite receiver, such as a Global Navigation Satellite System (GNSS), can be incorporated into a mobile device that consists of an electronic device or system. Such mobile devices can include, for example, household, industrial, and / or business electronic devices, vehicles, assets, ships, and the like. As described herein, the location estimation of a satellite receiver or a mobile device incorporating the satellite receiver may be referred to as the location, location estimation, location fix, fix, position, position estimation, or position fix of the satellite receiver or mobile device. Further, the location estimation can be geodetic and thus may or may not include an altitude component (e.g., height above sea level, height above or depth below the earth's surface, floor height, or underground depth) and provides the location coordinates (e.g., latitude and longitude) of the mobile device. In some embodiments, the location of the satellite receiver and / or the mobile device comprising the satellite receiver may be represented as an area or volume within which the satellite receiver is expected to be located with some probability or confidence (e.g., 68%, 95%, etc.), either geodesically or defined in a civic format. In the descriptions contained herein, the use of the term location may include any of these variations unless otherwise indicated. When calculating the location of the satellite receiver, such calculations can solve for local X, Y coordinates, and optionally Z coordinates, and then transform the coordinates from one coordinate frame to another as needed.

[0013] As described above, the embodiments described herein enable the generation of Real-Time Kinematic (RTK) correction information based on Precise Point Positioning (PPP) correction information by generating virtual multi-satellite system multi-frequency (MCMF) measurements corresponding to a virtual RTK base station location based on the PPP correction information. This RTK correction information can be sent to other devices that can process the RTK correction information but may not be able to process the PPP correction information. Further details follow after the initial description of the related systems and techniques.

[0014] FIG. 1 is a schematic diagram of a GNSS system 100 presented to show how GNSS is generally used to determine the precise location of a GNSS receiver 110 on the Earth 120 (also known as “positioning” of the GNSS receiver). Generally speaking, the GNSS system 100 enables an accurate GNSS position fix of the GNSS receiver 110 that receives radio frequency (RF) signals from GNSS satellites 130 of one or more GNSS satellite constellations. (Satellites such as the GNSS satellites 130 may also be referred to herein as space vehicles (SVs).) The type of GNSS receiver 110 used may vary depending on the application. In some embodiments, for example, the GNSS receiver 110 may consist of consumer electronics or devices such as mobile phones, tablets, laptops, wearable devices, vehicles (or in-vehicle devices), etc. In some embodiments, the GNSS receiver 110 may consist of industrial or commercial devices such as surveying equipment.

[0015] It will be understood that the figures presented in FIG. 1 are highly simplified. In reality, there can be dozens of satellites 130 and a given GNSS satellite constellation, and there are many different types of GNSS systems. Examples of GNSS systems include, for example, the Global Positioning System (GPS), Galileo (GAL), GLONASS, the Quasi-Zenith Satellite System (QZSS) over Japan, the Indian Regional Navigational Satellite System (IRNSS) over India, the BeiDou Navigation Satellite System (BDS) over China, etc. In addition to the basic positioning functions described later, GNSS augmentation (e.g., Satellite Based Augmentation System (SBAS)) can be used to provide higher accuracy. Such augmentation can be associated with or used in conjunction with one or more global and / or regional navigation satellite systems, such as, for example, the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), the Multi-functional Satellite Augmentation System (MSAS), and the Geo Augmented Navigation system (GAGAN).

[0016] GNSS positioning is based on multilateration, a method of determining a position by measuring the distances to known coordinate points. In general, the determination of the three-dimensional position of the GNSS receiver 110 can rely on the determination of the distances between the GNSS receiver 110 and four or more satellites 130. As shown, the 3D coordinates can be based on a coordinate system centered on the Earth's center of mass (e.g., XYZ, i.e., Cartesian coordinates, latitude, longitude, and altitude, i.e., geodetic coordinates, etc.). The distance between each satellite 130 and the GNSS receiver 110 can be determined using precise measurements made by the GNSS receiver 110 of the time difference between when the radio frequency (RF) signal is transmitted from each satellite 130 and received at the GNSS receiver 110. To help ensure accuracy, not only does the GNSS receiver 110 need to accurately determine when it receives each signal from each satellite 130, but many additional factors need to be considered and accounted for. These factors include, for example, the clock difference (e.g., clock bias) between the GNSS receiver 110 and the satellites 130, the precise location of each satellite 130 at the time of transmission (as determined, for example, by the broadcast ephemeris), the effects of atmospheric distortions (e.g., ionospheric delay and tropospheric delay), etc.

[0017] To perform a conventional GNSS position fix, the GNSS receiver 110 can use code-based positioning to determine the distance to each satellite 130 based on the determination of the delay of the generated pseudo-random binary sequence received in the RF signals received from each satellite, taking into account the additional factors and error sources described above. The GNSS receiver 110 can then determine the position fix of its location using the distance and location information of the satellite 130. This position fix can be determined, for example, by a standalone positioning engine (SPE) executed by one or more processors of the GNSS receiver 110. However, code-based positioning is not relatively accurate and, without error correction, is subject to many of the errors described above. Nevertheless, code-based GNSS positioning can provide positioning accuracy on the order of meters to the GNSS receiver 110.

[0018] More accurate carrier-based ranging is based on the carrier wave of the RF signal and can perform error correction to help reduce errors due to the aforementioned error sources using measurements at a base station or reference station (not shown). More specifically, errors in carrier-based ranging of satellite 130 observed by GNSS receiver 110 (e.g., atmospheric error sources) can be reduced or eliminated based on similar carrier-based ranging of satellite 130 using a high-precision GNSS receiver at a base station at a known location. These measurements and the location of the base station can be provided to GNSS receiver 110 for error correction. This position fix can be determined, for example, by a Precise Positioning Engine (PPE) executed by one or more processors of GNSS receiver 110. More specifically, in addition to the information provided to the SPE, the PPE can use GNSS measurement information of the base station, as well as additional correction information such as the troposphere and ionosphere, to provide a high-precision carrier-based position fix. Several GNSS techniques such as Differential GNSS (DGNSS), Real-Time Kinematic (RTK), and Precise Point Positioning (PPP) can be employed in the PPE and can provide an accuracy of less than 1 meter (e.g., on the order of centimeters).

[0019] Figure 2 is a block diagram of a PPP-based PPE 200 that can be used to determine an accurate position based on PPP. It can also be used at least in part to convert PPP correction information into RTK correction information and will be described below according to an embodiment. The blocks in Figure 2 include the data and logical processes used by the PPE to perform PPP-based positioning of a GNSS receiver (e.g., GNSS receiver 110 in Figure 1). As described above, the PPE can be executed by one or more processors of a GNSS receiver and / or a device (e.g., a mobile device) in which the GNSS receiver can be incorporated.

[0020] In block 210, the GNSS receiver obtains multi-band pseudorange (PR) and carrier phase (CP) measurements of signals from each of a plurality of satellites (e.g., satellite 130 in FIG. 1). As described above, the PR and CP measurements may respectively correspond to code-based and carrier-based measurements. To perform multi-band measurements (signal measurements using two or more frequencies transmitted by a satellite), embodiments may use a multi-band GNSS receiver (e.g., a dual-band receiver, a tri-band receiver, etc.) capable of receiving a plurality of frequency bands. Some embodiments may use a multi-constellation multi-frequency (MCMF) receiver capable of receiving a plurality of frequency bands on a plurality of satellite constellations. Examples of different bands for use in multi-band PR / CP measurements in block 210 include L1 / L5 for GPS, E1 / E5A for GAL, and B1C / B2A for BDS. Other embodiments may use additional or alternative bands and / or GPS satellite constellations.

[0021] In block 215, an ionosphere-free (IF) combination is formed. The ionosphere-free combination consists of a linear combination of code and / or carrier measurements that can remove the first-order ionosphere effect due to ionospheric refraction, which can improve the accuracy of the positioning solution. As shown by block 220, the ionosphere-free (IF) PR / CP measurements formed from the IF combination are provided to the PPP engine 225.

[0022] The advanced error modeling in block 230 consists of error modeling to reduce inaccuracies based on various error sources. Standard PPP error reduction techniques include error reduction techniques for reducing satellite code bias (DCB), satellite phase windup, site displacement, etc. These errors may result in inaccuracies of several meters or more, and reduction can be implemented by a Kalman filter (KF) that can estimate these errors / values.

[0023] The PPP engine 225 performs KF estimation using IF PR / CP measurement (block 220), advanced error modeling (block 230), and precise orbit and clock (block 235), and provides a PPP solution at block 240. As will be understood by those skilled in the art, the PPP engine can be implemented using an Extended Kalman Filter (EKF).

[0024] As described above, the device may utilize PPE to provide high-precision positioning using PPP and / or RTK correction information. Both PPP and RTK have advantages and disadvantages. RTK, which derives correction information from differential GNSS readings between a target device (or "mobile station") and one or more local base stations, has the advantages that the error modeling calculation is simple and the error cancellation performance is good. However, RTK has the disadvantages that a local or regional reference station is required and the bandwidth requirement is large (compared to PPP). PPP, which involves providing precise orbit / clock information to the target device (and optional ionospheric and tropospheric corrections for further improvement), has the advantages that the bandwidth requirement is small (compared to RTK) and the coverage is global. PPP has the disadvantage that complex error modeling calculations are required.

[0025] Although RTK is widely implemented in devices, there may be limited coverage, so a situation may occur where an RTK-capable device cannot provide a high-precision RTK-based position due to the lack of RTK correction information. This can occur despite the availability of PPP correction information with global coverage. Two scenarios illustrating such situations are shown in FIGS. 3A - 3B.

[0026] Figure 3A is a diagram of a server-based scenario 300-A in which device 310 is communicatively coupled to server 320. In this scenario, device 310 may include a GNSS receiver (e.g., GNSS receiver 110) and may receive positioning-related information from server 320 via a two-way communication link indicated by the double-sided arrows. (However, note that some embodiments may involve one-way communication from server 320.) The communication link may include wireless and / or wired communication via a public and / or private network (e.g., the Internet, a cellular network, etc.), and thus, information from server 320 to device 310 may be relayed by one or more intervening devices (not shown). In some embodiments, server 320 may be owned and / or maintained by a service provider such as a location service provider, a cellular service provider, etc. Server 320 may consist of a positioning server that can provide, for example, RTK correction information when available, as well as assistance data for terrestrial-based positioning methods (e.g., cellular-based positioning). Additionally, server 320 may also obtain PPP correction information 330 from a PPP service provider or other source. However, in the example of scenario 300-A, device 310 has an RTK engine 340 (e.g., as part of a PPE) but does not have a PPP engine (e.g., the PPP-based PPE 200 of FIG. 2). Thus, device 310 cannot provide a high-precision PPE solution when server 320 cannot provide RTK information.

[0027] Figure 3B is a diagram of a device-based scenario 300-B in which a first device 310-1 is communicatively coupled to a second device 310-2. In scenario 300-B, the first device 310-1 may provide location-related information to the second device 310-2 in the same manner as the server 320 provided location-related information to the device 310 in scenario 300-A. Again, the communication between the first device 310-1 and the second device 310-2 may be bidirectional (as shown) or unidirectional (from the first device 310-1 to the second device 310-2). This communication between the first device 310-1 and the second device 310-2 may be relayed by one or more intervening devices (not shown) or may be direct. The direct wireless interface between the first device 310-1 and the second device 310-2 may include, for example, Wi-Fi, Bluetooth®, 5G side link, etc. In this scenario 300-B, the first device 310-1 obtains PPP correction information 330 from a PPP source 350. Here, the PPP source 350 may be a third-party service provider (e.g., the same source from which the server 320 obtained the PPP correction information 330 in scenario 300-A) or another source (e.g., PPP correction information transmitted in the GAL E6 band, BDS B2B band, QZSS L6 band, etc.). Since the first device 310-1 is equipped with a PPP engine 360, it can demodulate and utilize the PPP correction information 330 to provide a high-precision PPE solution. However, similar to the device 310 in scenario 300-A, the second device 310-2 in scenario 300-B has a PPE that includes an RTK engine 340 but does not include a PPP engine. Therefore, the second device 310-2 cannot provide a high-precision PPE solution. Thus, in both scenarios 300-A and 300-B, the usefulness of the PPP correction information 330 is limited to only those devices that have a PPP engine 360 (e.g., the first device 310-1 in scenario 300-B).

[0028] Embodiments of this specification address these and other problems by enabling a device to generate RTK correction information that can be propagated as shown in FIGS. 4A-4B.

[0029] FIG. 4A is a diagram of a server-based scenario 400-A similar to scenario 300-A in which device 410 is communicatively coupled to server 420. Device 410, server 420, and the communication therebetween can be similar to the corresponding device 310, server 320, and communication described above with respect to scenario 300-A. However, here, server 420 may have additional functionality beyond that of server 320. In particular, in addition to obtaining PPP correction information 430 from a PPP service provider or other source, server 420 includes a PPE correction framework 433 that enables server 420 to generate RTK correction information 435, which is then sent to device 410 and processed by the RTK engine 440 of device 410 to enable device 410 to determine a PPE solution (e.g., the high-precision RTK-based position of each device 410).

[0030] Figure 4B is a diagram of a device-based scenario 400-B, showing how scenario 300-B can be similarly modified using the PPE correction framework 433 in the first device 410-1. Again, the device 410 and other components may be the same as those shown and described for scenario 300-B, but the first device 410-1 further includes a PPE correction framework 433 capable of generating RTK correction information 435. In scenario 400-B, the first device 410-1 obtains PPP correction information 430 from the PPP source 450 in the manner described for scenario 300-B. Again, since the first device 410-1 includes a PPP engine 460, it is possible to demodulate and utilize the PPP correction information 430 to provide a high-precision PPE solution (e.g., the high-precision PPP-based position of the first device 410-1). Further, since the first device 410-1 includes a PPE correction framework 433, it can generate RTK correction information 435 using the PPP correction 430 obtained from the PPP source 450. The RTK correction information 435 can then be sent to a second device 410-2, which can process the RTK correction information 435 using its RTK engine 440 to generate a PPE solution (e.g., the high-precision RTK-based position of the second device 410-2).

[0031] As shown in FIGS. 4A and 4B, various advantages are provided by enabling a device (e.g., server 420 or first device 410-1) to generate and propagate RTK correction information based on PPP correction information in the manner detailed in the embodiments herein. First, unlike conventional RTK services, no base station is required. Instead, correction information for virtual RTK base stations can be generated that can provide wide coverage across a geographical area. Further, no change to the receiving device having an RTK engine (e.g., RTK engine 440) is needed to enable processing of the RTK correction information. Also, since RTK engines are widespread, the embodiments described herein can ultimately enable a large number of devices to provide high-precision RTK-based positioning determinations by providing RTK correction information that otherwise would not exist.

[0032] The precise implementation of the PPE correction framework can vary depending on the desired functionality. Generally, the PPE correction framework can include hardware and / or software components that are capable of generating RTK correction information based on PPP correction information and generating the RTK correction information (e.g., as shown in FIGS. 9 and 10). An example of this process according to some embodiments is shown in FIG. 5.

[0033] FIG. 5 is a flowchart of a method 500 for providing RTK correction information for GNSS-based positioning according to one embodiment. In this method 500, the RTK correction information is generated at least in part based on the PPP correction information as described above. The means for performing the functions shown in one or more of the blocks shown in FIG. 5 can be implemented by hardware and / or software components of a server (e.g., server 420) or another electronic device including a mobile device (e.g., first device 410-1). Exemplary components of a mobile device are shown in FIG. 9 and exemplary components of a server are shown in FIG. 10, both of which are described in more detail below.

[0034] In block 510, the function includes obtaining PPP correction information in the first device. As described in the foregoing embodiments, the PPP correction information can be obtained from a third-party service that can transmit the PPP correction information via wired and / or wireless means using a public and / or private network (e.g., the Internet). Since satellites can transmit PPP correction information (e.g., such as the GAL E6 band, BDS B2B band, QZSS L6 band, etc. as described above), the PPP correction information can be directly obtained from the satellites if the first device is equipped with a GNSS receiver. The means for implementing the function in block 510 can include a bus 905, a processor 910, a digital signal processor (DSP) 920, a memory 960, a 300 GNSS receiver 980, and / or other components of the mobile device 900 as shown in FIG. 9, or a bus 1005, a processor 1010, a communication subsystem 1030, a wireless communication interface 1033, a memory 1035, an operating system 1040, an application 1045, and / or other components of the computer system 1000 as shown in FIG. 10.

[0035] In block 520, the function includes determining a virtual RTK base station location. Conventional RTK corrections involve the use of a base station at a known location having a high-precision GNSS receiver that measures GNSS signals. Method 500 emulates this by generating virtual GNSS (MCMF) measurements, which is initiated by determining a location where a "virtual" RTK base station can be located.

[0036] The location of the virtual RTK base station can vary according to the desired functionality. According to some embodiments, the first device may generate RTK correction information for receiving devices within a wide geographic area (e.g., a state, country, continent, or the entire globe). The geographic area may then be divided into smaller sub-areas where the virtual RTK base stations are located in each respective sub-area. In such embodiments, the first device can generate the RTK correction information of the virtual RTK base stations and send it to any / all GNSS devices located within each respective sub-area of the virtual RTK base stations for RTK-based positioning. The location of the virtual RTK base station can be predetermined based on the geometric configuration of the geographic area. The geographic area can be divided into sub-areas, for example, based on a grid pattern, and each cell within the grid can consist of a rectangle or square based on latitude and longitude (e.g., the cell size can be 5°×5°, 5°×10°, 10°×10°, etc.). Thus, in some embodiments of method 500, determining the virtual RTK base station location includes obtaining the virtual RTK base station location from a plurality of predetermined virtual RTK base station locations. Further, in some embodiments, the plurality of predetermined virtual RTK base station locations are geographically dispersed in a grid pattern.

[0037] In some embodiments, the location of the virtual RTK base station may be based on the location of a second device. That is, the first device can obtain RTK correction information on demand based on the location of the second device. In such cases, the second device (or another device) may provide the approximate location of the second device to the first device (e.g., based on conventional GNSS positioning, terrestrial wave-based positioning, etc.). Using this approximate location, the first device can then determine the location of the virtual RTK base station and generate RTK correction information for the second device. Such embodiments may determine the virtual RTK base station location, for example, by rounding the approximate location of the second device to the nearest degree of latitude and / or longitude. This can place the virtual RTK base station location several kilometers or tens of kilometers away from the second device, which can help set the accuracy expectation value of the second device to an appropriate level (whereas setting the virtual RTK base station location only a few meters away may, in some cases, result in a higher accuracy expectation value than the receiving device can provide).

[0038] Means for implementing the functions in block 520 may include a bus 905, a processor 910, a DSP 920, a memory 960, and / or other components of the mobile device 900 as shown in FIG. 9, or a bus 1005, a processor 1010, a communication subsystem 1030, a wireless communication interface 1033, a memory 1035, an operating system 1040, an application 1045, and / or other components of the computer system 1000 as shown in FIG. 10.

[0039] In block 530, the function includes generating virtual MCMF measurements corresponding to the determined virtual RTK base station location and based at least in part on PPP corrections. That is, using the PPP corrections, the first device can generate information for simulating what an actual RTK base station would measure at the virtual RTK base station location. Generation of the MCMF measurements can be performed using not only PPP orbit / clock corrections and (optionally) PPP troposphere and ionosphere corrections, but also broadcast ephemeris orbit / clock (which can be corrected by the PPP orbit / clock corrections), Sagnac effect corrections, troposphere and / or ionosphere models, satellite phase windup models, site displacement models (solid earth tides, ocean loading), and (optionally) measurement noise. An example of the generation of the MCMF out measurements will be described in more detail below with respect to FIG. 6.

[0040] Means for implementing the function in block 530 may comprise a bus 905, a processor 910, a DSP 920, a memory 960, a GNSS receiver 980, and / or other components of a mobile device 900 as shown in FIG. 9, or a bus 1005, a processor 1010, a communication subsystem 1030, a wireless communication interface 1033, a memory 1035, an operating system 1040, an application 1045, and / or other components of a computer system 1000 as shown in FIG. 10.

[0041] In block 540, method 500 includes transmitting, by the first device, RTK correction information based at least in part on the virtual MCMF measurements. The format used for transmission may be based on a format for transmitting RTK correction information, which may be based on the capabilities of the receiving device. For example, Radio Technical Commission for Maritime Services (RTCM) standards include RTCM3, which is often used for wireless communication and may include the virtual MCMF measurements themselves. On the other hand, RTCM2 is a different format that can be generated based on the virtual MCMF measurements.

[0042] As described above, the transmission of RTK correction information can vary. In some embodiments of method 500, transmitting the RTK correction information may include broadcasting the RTK correction information. In some embodiments of method 500, transmitting the RTK correction information may include sending the RTK correction information to a second device. In some cases, the second device may comprise a mobile GNSS device that uses the RTK correction information to determine its location. In such embodiments, if there is two-way communication between the first device and the second device, method 500 may further include receiving an indication of the location of the second device. In such cases, as described above, determining the virtual RTK base station location may be at least partially based on the location of the second device. As shown in FIG. 4B, the first device may consist of a mobile device, in which case the second device may also consist of a mobile device. As shown in FIG. 4A, the first device may consist of a server, in which case the second device may consist of any of various device types. For example, the second device may comprise a GNSS receiver, in which case the second device determines its location from the RTK correction received from the server. Alternatively, the second device may consist of a device that can propagate the RTK correction information. For example, in an embodiment where RTK correction information is provided to virtual RTK base stations in a geographic area divided into sub-regions forming a grid pattern, the RTK correction information corresponding to a virtual RTK base station located within a cell of the grid is sent to a device located within the cell and can be transmitted (e.g., broadcast) by the device to other devices within the cell. This can be repeated for each cell within the grid. Examples of physical devices for transmitting or broadcasting RTK correction information may include, for example, mobile devices, cellular base stations, radio towers, Internet of Things (IoT) devices, roadside units (RSUs) in a vehicle-to-vehicle / road-to-vehicle communication (V2X) regime, and the like.

[0043] The means for implementing the functions in block 540 may include a bus 905, a processor 910, a DSP 920, a memory 960, and / or other components of a mobile device 900 as shown in FIG. 9, or a bus 1005, a processor 1010, a communication subsystem 1030, a wireless communication interface 1033, a memory 1035, an operating system 1040, an application 1045, and / or other components of a computer system 1000 as shown in FIG. 10.

[0044] FIG. 6 is a table showing the generation of virtual MCMF measurements according to an example. In this example, the approximate location of the receiving device in Cartesian coordinates (XYZ in meters) is -2175327.6252, 4384343.1054, 4076110.5626. This is converted to geographical coordinates of latitude (degrees), longitude (degrees), and height (meters) of 39.9776432048829, 116.388683909549, and 41.8848. Using this approximate location of the receiving device, the location of the virtual RTK base station is determined by rounding to latitude 40.00 degrees, longitude 116.00 degrees, and height 42.00 meters, placing the virtual RTK base station location approximately 33 km from the receiving device. Once this virtual RTK base station location is determined, the values shown in FIG. 6, including simulated pseudoranges and carrier phases of the virtual MCMF measurements, can be determined using (among other things) PPP correction information. Details regarding the calculation of certain values are presented in FIG. 6. As described above, these measurements can then be provided (e.g., under RTCM3) or reformatted (e.g., under RTCM2) as RTK correction information to the receiving device.

[0045] The simulation results of RTK-based positioning using the RTK correction information generated using the techniques presented herein can provide accuracy similar to that of PPP-based positioning using the PPP correction information from which the RTK correction information is generated. A comparison of the PPP-based positioning and RTK-based positioning used in the simulation is shown in FIGS. 7 and 8.

[0046] FIG. 7 includes a graph showing simulated PPP-based positioning results of a device using PPP correction information. The first graph 710 plots the test position errors for east and north in the east, north, up (ENU) coordinate frame over time (about 900 epochs, each epoch being 1 second). The second graph 720 shows the corresponding cumulative distribution function (CDF) of the horizontal error (HE) of the simulation. As can be seen from the first graph 710, the position error starts at about 2 m and remains less than 1 m after about 100 epochs. Further, as shown by the second graph 720, 50% of the HE error values are less than 0.59 m and 95% are less than 2.07 m.

[0047] FIG. 8 includes graphs similar to those of FIG. 7, but shows simulation results of RTK-based positioning using RTK correction information generated using the techniques presented herein from the PPP correction information used in the simulation of FIG. 7. The first graph 810 plots the test position errors for east and north in the east, north, up (ENU) coordinate frame over time. The second graph 820 shows the corresponding CDF of the test HE. In the first graph 810, the position error generally reflects the positioning error of the graph 710 of FIG. 7, starting at about 2 m and decreasing to less than 1 m after about 100 epochs. Further, as shown by the second graph 820, 50% of the HE error values are less than 0.58 m and 95% are less than 1.73 m, which are values similar to those of the simulation of FIG. 7. Thus, generating RTK correction information using PPP correction information by the method described herein can provide positioning results having similar accuracy as when using the underlying PPP correction information.

[0048] FIG. 9 is a block diagram of various hardware and software components of a mobile device 900 according to an embodiment. These components can be utilized as described above in this specification (e.g., in relation to FIGS. 1-8). For example, the mobile device 900 can implement the operations of the method shown in FIG. 5 and / or one or more of the functions of a GNSS receiver as described in the embodiments of this specification. It should be noted that FIG. 9 is only intended to provide a generalized view of the various components, and any or all of those components can be utilized as needed. As previously mentioned, the mobile device 900 can ultimately comprise any GNSS-enabled device that may differ in form and function, including vehicles, commercial and household electronic devices, surveying instruments, etc. Thus, in some cases, the components shown in FIG. 9 can be localized in a single physical device and / or distributed among various networked devices that can be disposed at different physical locations (e.g., different locations in a vehicle). It should be further noted that a reference station can utilize hardware and / or software components similar to those of the mobile device 900.

[0049] A mobile device 900 is shown that includes hardware elements that can be electrically coupled via a bus 905 (or may communicate otherwise as appropriate). The hardware elements may include a processor 910, which may include, but is not limited to, one or more general-purpose processors, one or more dedicated processors (such as DSP chips, graphics processors (GPUs), application-specific integrated circuits (ASICs), etc.), and / or other processors, processing structures, processing units, or processing means. As shown in FIG. 9, some embodiments may have a separate DSP 920 depending on the desired functionality. Position determination and / or other determinations based on wireless communication can be performed at the processor 910 and / or the wireless communication interface 930 (discussed below). The mobile device 900 may also include one or more input devices 970 that can include, but are not limited to, a keyboard, touch screen, touch pad, microphone, buttons, dials, switches, etc., and one or more output devices 915 that can include, but are not limited to, a display, light-emitting diodes (LEDs), speakers, etc. It will be appreciated that the types of input device 970 and output device 915 may depend on the type of mobile device 900 with which the input device 970 and output device 915 are integrated.

[0050] Mobile device 900 may also include a wireless communication interface 930, which may include, without limitation, a modem, a network card, an infrared communication device, a wireless communication device, and / or a chipset such as (Bluetooth (R) device, IEEE802.11 device, IEEE802.15.4 device, Wi-Fi device, WiMAX (TM) device, wide area network (WAN) device, and / or various cellular devices, etc.), thereby enabling the mobile device 900 to communicate with other devices via a network and / or directly as described herein. The wireless communication interface 930 may enable data and signaling to be communicated (e.g., transmitted and received) with a network via, for example, a WAN access point, a cellular base station and / or other access node types, and / or other network components, a computer system, and / or any other electronic device described herein. Communication can be performed via one or more wireless communication antennas 932 that transmit and / or receive wireless signals 934. The antenna 932 may comprise one or more individual antennas, one or more antenna arrays, or any combination thereof.

[0051] Depending on the desired functionality, the wireless communication interface 930 may comprise a separate transceiver, a separate receiver and transmitter, or any combination of transceivers, transmitters, and / or receivers to communicate with a base station and other terrestrial transceivers such as wireless devices and access points. The mobile device 900 may communicate with different data networks that may comprise various network types. For example, a wireless wide area network (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, a WiMAX (trademark) (IEEE802.16) network, etc. The CDMA network may implement one or more radio access technologies (RATs) such as CDMA2000 (registered trademark), wideband CDMA (WCDMA (registered trademark)), etc. CDMA2000 (registered trademark) includes the IS-95 standard, the IS-2000 standard, and / or the IS-856 standard. The TDMA network may implement Global System for Mobile Communications (GSM), Digital Advanced Mobile Phone System (D-AMPS), or some other RAT. The OFDMA network may adopt Long Term Evolution (LTE), LTE Advanced, 5G NR, 6G, etc. 5G NR, LTE, LTE Advanced, GSM, and WCDMA (registered trademark) are described in documents from the 3rd Generation Partnership Project (3GPP (registered trademark)). CDMA2000 (registered trademark) is described in documents from a body named "3rd Generation Partnership Project 2" (3GPP2). The 3GPP (registered trademark) documents and 3GPP2 documents are publicly available. The wireless local area network (WLAN) may also be an IEEE802.11x network, and the wireless personal area network (WPAN) may be a Bluetooth (registered trademark) network, IEEE802.15x, or some other types of networks.The techniques described herein may also be used for any combination of WWAN, WLAN, and / or WPAN.

[0052] Mobile device 900 may further include a sensor 940. Sensor 940 may comprise, without limitation, one or more inertial sensors and / or other sensors (e.g., accelerometers, gyroscopes, cameras, magnetometers, altimeters, microphones, proximity sensors, light sensors, barometers, etc.), some of which may, in some instances, be used to complement and / or facilitate the location determination described herein.

[0053] Embodiments of mobile device 900 may also include a GNSS receiver 980 that is capable of receiving a signal 984 from one or more GNSS satellites (e.g., satellite 130) as described herein using an antenna 982 (which may be the same as antenna 932). GNSS receiver 980 may use conventional techniques to extract the position of mobile device 900 from GNSS SVs (e.g., SV 140 of FIG. 3) of a GNSS system such as GPS, GAL, Global Navigation Satellite System (GLONASS), Quasi-Zenith Satellite System (QZSS) over Japan, Indian Regional Navigation Satellite System (IRNSS) over India, BeiDou Navigation Satellite System (BDS) over China, etc. Further, GNSS receiver 980 may be used in conjunction with, or otherwise enabled for use with, various augmentation systems (e.g., satellite-based augmentation system (SBAS)) associated with or used with one or more global and / or regional navigation satellite systems such as, for example, Wide Area Augmentation System (WAAS), European Geostationary Navigation Overlay Service (EGNOS), Multi-functional Satellite Augmentation System (MSAS), and GPS Aided Geo Augmented Navigation (GAGAN).

[0054] Although the GNSS receiver 980 shown in FIG. 9 is shown as a component separate from other components within the mobile device 900, it may be noted that the embodiments are not so limited. The term "GNSS receiver" as used herein may include hardware components and / or software components configured to acquire GNSS measurements (measurements from GNSS satellites). In some embodiments, therefore, the GNSS receiver may comprise a measurement engine (as software) executed by one or more processors, such as a processor within the processor 910, DSP 920, and / or wireless communication interface 930 (e.g., within a modem). The GNSS receiver may also optionally include a positioning engine (e.g., a PPE and / or an SPE that may be implemented using one or more of KF, weighted least squares (WLS), a hatch filter, a particle filter, etc.) as described herein, and the positioning engine may use a PPP engine (as described with respect to FIG. 2, for example) to determine a PPE solution using PPP correction information as described herein and / or generate RTK correction information. The positioning engine may also be executed by one or more processors such as the processor 910 and / or DSP 920.

[0055] The mobile device 900 may further include and / or communicate with a memory 960. The memory 960 may comprise a machine-readable or computer-readable medium comprising, without limitation, solid-state storage devices such as local storage and / or network-accessible storage, disk drives, drive arrays, optical storage devices, random access memory (RAM) and / or read-only memory (ROM) that may be programmable, flash updatable, etc. Such storage devices may be configured to implement any suitable data store, including, without limitation, various file systems, database structures, etc.

[0056] The memory 960 of the mobile device 900 may also include software elements (not shown in FIG. 9) such as an operating system, device drivers, executable libraries, and / or other code such as one or more application programs, which may include computer programs provided by various embodiments as described herein, and / or implement methods provided by other embodiments, and / or be designed to configure systems provided by other embodiments. By way of example only, one or more of the procedures described above with respect to the method may be implemented as code and / or instructions in the memory 960 executable by the mobile device 900 (and / or the processor 910 or DSP 920 within the mobile device 900). In one aspect, such code and / or instructions may then be used to configure and / or adapt a general-purpose computer (or other device) to perform one or more operations in accordance with the described method.

[0057] FIG. 10 is a block diagram of an embodiment of a computer system 1000 that may be used in whole or in part to provide the functionality of a computer and / or server (e.g., server 420 of FIG. 4A) as described in embodiments of this specification. It should be noted that FIG. 10 is only intended to provide a generalized illustration of various components, and any or all of those components may be utilized as needed. Further, the computer system 100 may be capable of implementing some or all of the functionality of the method 500 of FIG. 5. FIG. 10 broadly shows how individual system elements can be implemented in a relatively separated or relatively integrated manner. Additionally, it can be noted that the components shown by FIG. 10 can be localized to a single device and / or distributed among various networked devices located at different geographical locations.

[0058] A computer system 1000 is shown that includes hardware elements that can be electrically coupled via a bus 1005 (or communicate in other ways as needed). The hardware elements can include, but are not limited to, one or more general-purpose processors, one or more dedicated processors (such as digital signal processing chips, graphics decision acceleration processors, etc.), and / or other processing structures that can be configured to execute one or more of the methods described herein, including a processor 1010. The computer system 1000 can also include, but is not limited to, one or more input devices 1015 that can include a mouse, keyboard, camera, microphone, etc., and one or more output devices 1020 that can include, but are not limited to, a display device, printer, etc.

[0059] The computer system 1000 may further include (and / or communicate with) one or more non-transitory storage devices 1025, and the one or more non-transitory storage devices 1025 can include, but are not limited to, local and / or network-accessible storage, and / or can include solid-state storage devices such as RAM and / or ROM that can be, for example, disk drives, drive arrays, optical storage devices, programmable, flash updatable, etc. Such storage devices may be configured to implement any suitable data store, including, but not limited to, various file systems, database structures, etc. Such a data store may include databases and / or other data structures used to store and manage messages and / or other information to be sent to one or more devices via a hub, as described herein.

[0060] The computer system 1000 may also include a communication subsystem 1030, which may include wireless communication technologies managed and controlled by a wireless communication interface 1033, as well as wired technologies (such as Ethernet, coaxial communication, universal serial bus (USB), etc.). The wireless communication interface 1033 may include one or more wireless transceivers capable of transmitting and receiving wireless signals 1055 (e.g., signals by 5G NR or LTE) via a wireless antenna 1050. Thus, the communication subsystem 1030 may include a modem, a network card (wireless or wired), an infrared communication device, a wireless communication device, and / or a chipset, etc., whereby the computer system 1000 can communicate with any or all of the communication networks described herein, with any device on each network and / or any other electronic device described herein. Thus, the communication subsystem 1030 may be used to transmit and receive data as described in the embodiments herein. In some embodiments, the computer system 1000 may include a GNSS receiver, which may be a separate component (not shown) and / or may be incorporated into another component of the computer system 1000.

[0061] In many embodiments, computer system 1000 may further include a working memory 1035 that can include a RAM device or a ROM device, as described above. Software elements shown as being located within working memory 1035 may include an operating system 1040, device drivers, executable libraries, and / or other code such as one or more applications 1045, which may include computer programs provided by various embodiments, as described herein, and / or implement methods provided by other embodiments, and / or be designed to configure systems provided by other embodiments. By way of example only, one or more of the procedures described with respect to the methods above may be implemented as code and / or instructions executable by a computer (and / or a processor within the computer). In one aspect, such code and / or instructions can then be used to configure and / or adapt a general-purpose computer (or other device) to perform one or more operations in accordance with the described methods.

[0062] These sets of instructions and / or code can be stored in a non-transitory computer-readable storage medium such as the storage device 1025 described above. In some cases, the storage medium may be incorporated within a computer system such as the computer system 1000. In other embodiments, the storage medium may be separate from the computer system (e.g., a removable medium such as an optical disk) and / or may be provided in an installation package so that it can be used to program, configure, and / or adapt a general-purpose computer using the instructions / code stored thereon. These instructions may take the form of executable code executable by the computer system 1000 and / or may take the form of source and / or installable code, which, when compiled and / or installed on the computer system 1000 (e.g., using any of various generally available compilers, installation programs, compression / decompression utilities, etc.), then takes the form of executable code.

[0063] It will be apparent to those skilled in the art that substantial variations may be made in accordance with specific requirements. For example, customized hardware may also be used and / or certain elements may be implemented in hardware, software (including portable software such as applets), or both. Additionally, connections to other computing devices such as network input / output devices may be employed.

[0064] Referring to the accompanying drawings, a component that may include a memory may include a non-transitory machine-readable medium. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any storage medium involved in providing data that causes a machine to operate in a particular manner. In the embodiments provided above, various machine-readable media may be involved in providing instructions / codes to a processor and / or other devices for execution. Additionally or alternatively, a machine-readable medium may be used to store and / or carry such instructions / codes. In many implementations, a computer-readable medium is a physical and / or tangible storage medium. Such media can take many forms, including but not limited to non-volatile media and volatile media. Common forms of computer-readable media include, for example, magnetic and / or optical media, any other physical media having a pattern of holes, RAM, programmable ROM (PROM), erasable PROM (EPROM), FLASH-EPROM, any other memory chip or cartridge, or any other medium that a computer can read instructions and / or codes from.

[0065] The methods, systems, and devices described herein are examples. Various embodiments may, as appropriate, omit, substitute, or add various procedures or components. For example, features described with respect to some embodiments may be combined in various other embodiments. Different aspects and elements of embodiments may also be combined. The various components of the figures provided herein may be embodied in hardware and / or software. Also, technology evolves, and thus many of the elements are examples that do not limit the scope of the present disclosure to their specific examples.

[0066] For reasons mainly related to common usage, it has been found that it is sometimes convenient to refer to such signals as bits, information, values, elements, symbols, characters, variables, terms, numbers, numerical values, etc. However, it should be understood that all of these or similar terms are merely convenient labels and must be associated with appropriate physical quantities. Unless otherwise specified, as is apparent from the above description, throughout this specification, descriptions using terms such as "process", "calculate", "compute", "determine", "verify", "specify", "associate", "measure", "execute", etc. are understood to refer to the actions or processes of a specific device such as a dedicated computer or a similar dedicated electronic computing device. Thus, in the context of this specification, a dedicated computer or a similar dedicated electronic computing device is capable of operating or transforming signals generally represented as electronic, electrical, or magnetic physical quantities within the memory, registers, or other information storage devices, transmission devices, or display devices of the dedicated computer or similar dedicated electronic computing device.

[0067] The terms "and" and "or" as used in this specification may include various meanings that are also expected to depend at least in part on the context in which such terms are used. Generally, "or" is intended to mean A, B, and C, where A, B, or C, etc. are used to associate a list, and here it is used in an inclusive sense, and A, B, or C, where it is used in an exclusive sense. In addition, the term "one or more" as used in this specification may be used to represent any feature, structure, or property in the singular form, or may be used to represent some combination of features, structures, or properties. However, it should be noted that this is only an illustrative example for explanation, and the claimed subject matter is not limited to this example. Further, the term "at least one of" when used to associate an enumeration such as A, B, or C, etc. may be interpreted to mean any combination of A, B, and / or C, such as A, AB, AA, AAB, AABBCCC, etc.

[0068] Although several embodiments are described, various modifications, alternative configurations, and equivalents may be used without departing from the scope of the disclosure. For example, the above elements may merely be components of a larger system, other rules may take precedence over the application examples of the various embodiments, or the application examples of the various embodiments may be modified differently. Also, several steps may be initiated before, during, or after the above elements are considered. Accordingly, the above description does not limit the scope of the disclosure.

[0069] In view of this specification, embodiments may include various combinations of features. Implementation examples are described in the following numbered clauses.

[0070] Clause 1. A method for providing real-time kinematic (RTK) correction information for global navigation satellite system (GNSS)-based positioning, comprising obtaining precise point positioning (PPP) correction information in a first device, determining a virtual RTK base station location, generating virtual multi-constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location and at least partially based on the PPP correction information, and transmitting RTK correction information at least partially based on the virtual MCMF measurements by the first device.

[0071] Clause 2. The method according to clause 1, wherein transmitting the RTK correction information includes sending the RTK correction information to a second device.

[0072] Clause 3. The method according to clause 1 or 2, further comprising receiving an indication of the location of the second device, wherein determining the virtual RTK base station location is at least partially based on the location of the second device.

[0073] Clause 4. The method according to any one of clauses 1 to 3, wherein the first device comprises a server and the second device comprises a mobile device or a cellular base station.

[0074] The method according to any one of clauses 1 to 3, wherein the first device comprises a first mobile device and the second device comprises a second mobile device.

[0075] The method according to clause 1 or 2, wherein determining a virtual RTK base station location includes obtaining the virtual RTK base station location from a plurality of predetermined virtual RTK base station locations.

[0076] The method according to clause 6, wherein the plurality of predetermined virtual RTK base station locations are geographically dispersed in a grid pattern.

[0077] The method according to any one of clauses 1 to 7, wherein transmitting RTK correction information includes broadcasting the RTK correction information.

[0078] A device for providing real-time kinematic (RTK) correction information for global navigation satellite system (GNSS)-based positioning, comprising a transceiver, a memory, and one or more processors communicatively coupled to the transceiver and the memory, wherein the one or more processors obtain precise point positioning (PPP) correction information, determine a virtual RTK base station location, generate virtual multi-constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location and based at least in part on the PPP correction information, and are configured to transmit, via the transceiver, RTK correction information based at least in part on the virtual MCMF measurements by the device.

[0079] The device according to clause 9, wherein, to transmit the RTK correction information, one or more processors are configured to send the RTK correction information to a second device.

[0080] Clause 11. The device according to clause 9 or 10, wherein one or more processors are further configured to receive an indication of the location of a second device, and one or more processors are further configured to determine a virtual RTK base station location at least partially based on the location of the second device.

[0081] Clause 12. The device according to any one of clauses 9 to 11, wherein the device comprises a server and the second device comprises a mobile device or a cellular base station.

[0082] Clause 13. The device according to any one of clauses 9 to 11, wherein the device comprises a first mobile device and the second device comprises a second mobile device.

[0083] Clause 14. The device according to any one of clauses 9 to 13, wherein one or more processors are configured to obtain a virtual RTK base station location from a plurality of predetermined virtual RTK base station locations in order to determine the virtual RTK base station location.

[0084] Clause 15. The device according to clause 14, wherein the plurality of predetermined virtual RTK base station locations are geographically dispersed in a grid pattern.

[0085] Clause 16. The device according to any one of clauses 9 to 15, wherein one or more processors are configured to broadcast RTK correction information in order to transmit the RTK correction information.

[0086] Clause 17. An apparatus for providing real-time kinematic (RTK) correction information for global navigation satellite system (GNSS)-based positioning, the apparatus comprising means for obtaining precise point positioning (PPP) correction information, means for determining a virtual RTK base station location, means for generating virtual multi-constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location and at least partially based on the PPP correction information, and means for transmitting RTK correction information at least partially based on the virtual MCMF measurements by the apparatus.

[0087] Clause 18. The apparatus according to clause 17, wherein the means for transmitting RTK correction information comprises means for sending the RTK correction information to a device separate from the apparatus.

[0088] Clause 19. The apparatus according to clause 17 or 18, further comprising means for receiving an indication of the location of a device separate from the apparatus, wherein determining the virtual RTK base station location is at least partially based on the location of the device separate from the apparatus.

[0089] Clause 20. The apparatus according to any one of clauses 17 to 19, wherein the apparatus comprises a server and the device separate from the apparatus comprises a mobile device or a cellular base station.

[0090] Clause 21. The apparatus according to any one of clauses 17 to 19, wherein the apparatus comprises a first mobile device and the device separate from the apparatus comprises a second mobile device.

[0091] Clause 22. The apparatus according to any one of clauses 17 to 21, wherein the means for determining the virtual RTK base station location comprises means for obtaining the virtual RTK base station location from a plurality of predetermined virtual RTK base station locations.

[0092] Clause 23. The apparatus according to clause 22, wherein the plurality of predetermined virtual RTK base station locations are geographically dispersed in a grid pattern.

[0093] Clause 24. The device according to any one of Clauses 17 to 23, wherein the means for transmitting RTK correction information comprises means for broadcasting the RTK correction information.

[0094] Clause 25. A non-transitory computer-readable medium storing instructions for providing real-time kinematic (RTK) correction information for positioning based on a global navigation satellite system (GNSS), the instructions causing a first device to obtain precise point positioning (PPP) correction information, determine a virtual RTK base station location, generate virtual multi-constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location and at least partially based on the PPP correction information, and transmit RTK correction information at least partially based on the virtual MCMF measurements by the first device.

[0095] Clause 26. The computer-readable medium according to Clause 25, wherein the code for transmitting RTK correction information comprises code for sending the RTK correction information to a second device.

[0096] Clause 27. The instructions further comprise code for receiving an indication of the location of a second device, and determining the virtual RTK base station location is at least partially based on the location of the second device. The computer-readable medium according to Clause 25 or 26.

[0097] Clause 28. The computer-readable medium according to any one of Clauses 25 to 27, wherein the first device comprises a server and the second device comprises a mobile device or a cellular base station.

[0098] Clause 29. The computer-readable medium according to any one of Clauses 25 to 27, wherein the first device comprises a first mobile device and the second device comprises a second mobile device.

[0099] A computer-readable medium according to any one of clauses 25 to 29, wherein the code for determining a virtual RTK base station location includes code for obtaining a virtual RTK base station location from a plurality of predetermined virtual RTK base station locations.

[0100] A computer-readable medium according to clause 30, wherein a plurality of predetermined virtual RTK base station locations are geographically dispersed in a grid pattern.

[0101] A computer-readable medium according to any one of clauses 25 to 31, wherein the code for transmitting RTK correction information includes code for broadcasting the RTK correction information.

Claims

1. 1. A method for providing real-time kinematic (RTK) correction information for Global Navigation Satellite System (GNSS) based positioning, comprising: receiving, by a server, an indication of a location of a second device, the second device being a mobile device or a base station; obtaining, at the server, precise point positioning (PPP) corrections corresponding to the location, the PPP corrections being obtained by the server from a PPP service provider; determining, by the server, a virtual RTK base station location from a plurality of predefined virtual RTK base station locations; generating, by the server, virtual multi-satellite constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location based at least in part on the PPP corrections, the virtual MCMF measurements emulating MCMF measurements that would be generated by a reference station based on the RTK corrections; transmitting, by the server, the RTK correction information to the second device, the RTK correction information being based at least in part on the virtual MCMF measurements generated by the server; A method comprising:

2. The method of claim 1, wherein the step of generating the virtual MCMF measurement is part of converting the PPP correction information into the RTK correction information usable by the second device.

3. The method of claim 1 , wherein the plurality of predefined virtual RTK base station locations are geographically distributed in a grid pattern.

4. The method of claim 1 , wherein transmitting the RTK correction information comprises broadcasting the RTK correction information.

5. 1. A server for providing real-time kinematic (RTK) correction information for Global Navigation Satellite System (GNSS)-based positioning, comprising: A transceiver; Memory, one or more processors communicatively coupled to the transceiver and the memory, receiving an indication of a location of a second device, the second device being a mobile device or a base station; obtaining precise point positioning (PPP) corrections corresponding to the location, the PPP corrections being obtained by the server from a PPP service provider; determining a virtual RTK base station location from a plurality of predetermined virtual RTK base station locations; generating virtual multi-satellite constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location based at least in part on the PPP correction information, the virtual MCMF measurements emulating MCMF measurements that should be generated by a base station based on the RTK correction information; transmitting the RTK correction information to the second device, the RTK correction information being based at least in part on the virtual MCMF measurements; and one or more processors configured to A server comprising:

6. The server of claim 5 , wherein generating the virtual MCMF measurements is part of converting the PPP correction information into the RTK correction information usable by a second device.

7. The server of claim 5 , wherein the plurality of predefined virtual RTK base station locations are geographically distributed in a grid pattern.

8. The server of claim 5 , wherein to transmit the RTK correction information, the one or more processors are configured to broadcast the RTK correction information.

9. 1. A server for providing real-time kinematic (RTK) correction information for Global Navigation Satellite System (GNSS)-based positioning, comprising: means for receiving an indication of a location of a device, separate from the server, the device being a mobile device or a base station; means, at the server, for obtaining Precise Point Positioning (PPP) correction information corresponding to the location, the PPP correction information being obtained by the server from a PPP service provider; means for determining a virtual RTK base station location from a plurality of predetermined virtual RTK base station locations; means for generating virtual multi-satellite constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location based at least in part on the PPP correction information, the virtual MCMF measurements emulating MCMF measurements that would be generated by a reference station based on the RTK correction information; means for transmitting the RTK correction information to the device using the server, the RTK correction information being based at least in part on the virtual MCMF measurements; A server comprising:

10. 10. The server of claim 9, wherein the plurality of predefined virtual RTK base station locations are geographically distributed in a grid pattern.

11. The server of claim 9 , wherein the means for transmitting the RTK correction information comprises means for broadcasting the RTK correction information.

12. 1. A non-transitory computer-readable storage medium storing instructions for providing real-time kinematic (RTK) correction information for Global Navigation Satellite System (GNSS) based positioning, the instructions comprising: receiving, by one or more processors of a server, an indication of a location of a second device, the second device being a mobile device or a base station; obtaining, by the one or more processors, precise point positioning (PPP) correction information corresponding to the location, the PPP correction information being obtained by the server from a PPP service provider; determining, by the one or more processors, a virtual RTK base station location from a plurality of predetermined virtual RTK base station locations; generating, by the one or more processors, virtual multi-satellite constellation multi-frequency (MCMF) measurements corresponding to the determined virtual RTK base station location based at least in part on the PPP correction information, the virtual MCMF measurements emulating MCMF measurements that would be generated by a reference station based on the RTK correction information; transmitting, by the one or more processors, to the second device, the RTK correction information based at least in part on the virtual MCMF measurements; 16. A computer readable storage medium comprising code for performing the steps of:

13. 13. The computer-readable storage medium of claim 12, wherein the plurality of predefined virtual RTK base station locations are geographically distributed in a grid pattern.

14. 13. The computer-readable storage medium of claim 12, wherein the code for transmitting the RTK correction information comprises code for broadcasting the RTK correction information.

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