Embodiments described herein provide for enabling a mobile device comprising a GNSS receiver to implement a modified PPP technique that utilizes orbit and clock information of a satellite that is broadcast from the satellite. In particular, embodiments may utilize a positioning engine to perform PPP error mitigation with respect to various error sources (e.g., troposphere, ionosphere, phase windup, etc.). With regard to errors stemming from satellite orbit and satellite clock, embodiments may utilize orbit and clock information from broadcast ephemeris data rather than obtaining precise orbit and clock information (e.g., from a third party provider). Further, embodiments may account for errors in this broadcast information by adjusting the ambiguity dynamic and/or ambiguity estimate term used by the positioning engine. This can enable the positioning engine to determine a solution more accurate than traditional GNSS without resetting.

A method for disseminating corrections can include receiving a set of satellite observations at a GNSS receiver; transmitting the corrections to the GNSS receiver, wherein the corrections; and determining a position of the GNSS receiver, wherein the set of satellite observations are corrected using the corrections. A system for disseminating corrections can include a positioning engine operating on a computing system collocated with a GNSS antenna; and a corrections generator operating on a computing system remote from the GNSS antenna, wherein the corrections generator is configured to transmit corrections to the positioning engine, wherein the positioning engine is configured to determine a high accuracy position of the GNSS antenna using the corrections, wherein the corrections are rebroadcast to the positioning engine with a time period less than an update time period for changing the corrections.

A system is for determining a position on a golf course. The system has a master unit and at least one slave unit. The master unit and the at least one slave unit are adapted to communicate through a telecommunications network. The master unit comprises a receiver for a satellite navigation system, the receiver being operable at a fixed position on the golf course. The master unit is configured to: obtain a position determined by the receiver; process the displacement between the obtained position and the fixed position; and make the processed displacement available to the at least one slave unit through the telecommunications network. A slave unit then makes use of the processed displacement to improve positions determined by itself.

The present invention discloses a high-precision point positioning method and device based on a smartphone. The method of the present invention, which belongs to the technical field of satellite positioning, improves the conventional PPP uncombined positioning model, and only uses original GNSS observation values received by a smartphone to carry out high-precision positioning without GNSS reference stations. The positioning method of the present invention comprises following steps: acquiring original observation values of the smartphone, such as GNSS pseudoranges and carrier phases; after preprocessing the data to decrease part of error influences, generating an uncombined model from the original observation values according to an improved precise point positioning method based on an estimation of double clock biases; determining each satellite observation value weight according to a satellite elevation angle; and carrying out filtering positioning by an improved Kalman filtering method to give a high-precision point positioning result.

Described are methods, systems, and devices for correcting ionospheric error. In some aspects, a mobile device equipped with a Global Navigation Satellite System (GNSS) receiver is configured to determine a positioning measurement of a GNSS signal. The mobile device is further configured to receive augmentation data from an augmentation system. When augmentation data for a current measurement period is unavailable, the mobile device can obtain augmentation data associated with Total Electron Content (TEC) values (e.g., vertical TEC values) during one or more prior measurement periods. Based on the augmentation data associated with TEC values during one or more prior measurement periods and a pierce point of the received GNSS signal, an ionospheric error in the positioning measurement of the GNSS signal can be determined and corrected.

A method for disseminating corrections can include receiving a set of satellite observations at a GNSS receiver; transmitting the corrections to the GNSS receiver, wherein the corrections; and determining a position of the GNSS receiver, wherein the set of satellite observations are corrected using the corrections. A system for disseminating corrections can include a positioning engine operating on a computing system collocated with a GNSS antenna; and a corrections generator operating on a computing system remote from the GNSS antenna, wherein the corrections generator is configured to transmit corrections to the positioning engine, wherein the positioning engine is configured to determine a high accuracy position of the GNSS antenna using the corrections, wherein the corrections are rebroadcast to the positioning engine with a time period less than an update time period for changing the corrections.

Methods and systems are provided for measuring the zeta potential of macroscopic solid surfaces including and not limited to: porous samples, flat substrates, coarse particles, and granular samples. Methods include: subjecting the sample to an injection of a first aqueous solution at an initial pressure with an initial ion concentration; measuring a first electrical conductivity and a first temperature of the first aqueous solution; measuring a first pH and a second pH of the first aqueous solution immediately before and after passing the first aqueous solution through the sample; measuring a first ion concentration and a second ion concentration of the first aqueous solution immediately before and after passing the first aqueous solution through the sample; and processing the measured data to derive a first zeta potential from the first electrical conductivity and the first temperature.

A Real-Time Kinematic (RTK) solution is provided to mobile devices having multi-constellation, multi-frequency (MCMF) functionality, in which a single base station may have a baseline much farther than traditional base station and where the high accuracy positioning is achieved in a relatively short period of time. To enable this, embodiments involve modeling of an ionosphere-free carrier phase corresponding to combinations of at least three signals received from one or more satellites. The modeling retains the integer nature of carrier phase ambiguities, thereby allowing for fast convergence in determining the integer ambiguity of the carrier phases.

A method for determining a four-dimensional ionosphere model of an electron distribution in the Earth's atmosphere is disclosed, which is used to correct runtime measurements of signals emitted by satellites, for position determinations by means of signal receivers. The method comprises: a) defining at least one distribution function based on at least one function parameter which is suitable to describe a distribution of electrons over the height of the Earth's atmosphere; b) receiving data from a plurality of runtime measurements by means of a plurality of movable dual-frequency signal receivers, in order to determine parameters that are representative for a total quantity of electrons along a signal transmission path from a satellite to a dual-frequency signal receiver; c) determining location-dependent and time-dependent function parameters for the distribution function at least by means of the parameters; and d) providing the function parameters determined in step c) as a four-dimensional ionosphere model.

A method, apparatus and computer program product determine a position of a client computing device. In the context of a method, a parameter, such as an orbit or a clock, associated with a respective navigation satellite are predicted, with the client computing device, based on data associated with the respective navigation satellite. The method also includes providing time information to a correction service identifying the data used as a basis for predicting the parameter associated with the respective navigation satellite. The method further includes receiving, from the correction service, a correction to the parameter that has been predicted for the respective navigation satellite and determining the position of the client computing device based upon the parameter that has been predicted for the respective navigation satellite in combination with the correction thereto.