Disclosed in some examples are methods, systems and machine readable mediums to efficiently stream data across restricted networks. In some examples, this streamed data may be sent more efficiently using lower overhead protocols such as UDP. In order to bypass the aforementioned limitations on these lower overhead protocols, the client may send a periodic update message to the server. This update message maintains the openings in the network firewalls and updates the server on the client's status. This update message may be sent much less frequently than a typical TCP acknowledgement, and the lower overhead protocol may be a protocol that does not retransmit lost or corrupted packets—thereby eliminating unnecessary overhead. In some examples this streamed data may be GNSS correction data. In some examples, the client may be behind one or more network firewalls.

In a system for navigating a moving object according to signals received from satellites, a moving object receives mobile base data from a mobile base station, the received mobile base data including satellite measurement data of the mobile base station, the satellite measurement data of the mobile base station including code measurements and carrier phase measurements for the plurality of satellites, and position-related information of the mobile base station. In accordance with the satellite navigation data for the moving object and the received mobile base data, the moving object performing a real-time kinematic (RTK) computation process to resolve carrier phase ambiguities and determine a relative position of the moving object relative to the mobile base station. A signal reporting information corresponding to the relative position is sent via a transmitter of the moving object.

In a system for navigating a moving object according to signals received from satellites, a moving object receives mobile base data from a mobile base station, the received mobile base data including satellite measurement data of the mobile base station, the satellite measurement data of the mobile base station including code measurements and carrier phase measurements for the plurality of satellites, and position-related information of the mobile base station. In accordance with the satellite navigation data for the moving object and the received mobile base data, the moving object performing a real-time kinematic (RTK) computation process to resolve carrier phase ambiguities and determine a relative position of the moving object relative to the mobile base station. A signal reporting information corresponding to the relative position is sent via a transmitter of the moving object.

A method and apparatus are provided for calculating a position of a first device relative to a reference device for a current time. The method comprises obtaining first reference GNSS measurements, made at the reference device for a first time, obtaining the position of the reference device for the first time, obtaining first device GNSS measurements, made at the first device for the current time, and calculating a first relative position between the first device at the current time and the reference device at the first time. The method further comprises obtaining second reference GNSS measurements, made at the reference device for a second time subsequent to the first time, calculating a position change of the reference device from the first time to the second time, and calculating the second relative position between the first device at the current time and the reference device at the second time.

A system or method for determining a satellite observation for a virtual reference station can include: determining a virtual reference station location, receiving a set of satellite observations at a reference station located at a reference station location, determining a first GNSS correction for the virtual reference station location and a second GNSS correction for the reference station location, and determining the satellite observation for the virtual reference station by combining the set of satellite observations, the first GNSS correction, and the second GNSS correction.

Techniques described herein leverage multi-constellation, multi-frequency (MCMF) functionality to provide a local Real-Time Kinematic (RTK) solution for a mobile device in which an initial highly-accurate location determination for the mobile device can be leveraged to generate RTK correction information that can be used to make subsequent, highly-accurate location determinations without the need for measurement information from an RTK base station. This RTK correction information can be applied to Global Navigation Satellite System (GNSS) measurements taken by the mobile device over a long period of time while retaining the ability to produce highly-accurate location determinations for the mobile device. And additional correction information may be obtained and applied to the RTK correction information to extend this period of time even longer.

Techniques described herein leverage multi-constellation, multi-frequency (MCMF) functionality to provide a local Real-Time Kinematic (RTK) solution for a mobile device in which an initial highly-accurate location determination for the mobile device can be leveraged to generate RTK correction information that can be used to make subsequent, highly-accurate location determinations without the need for measurement information from an RTK base station. This RTK correction information can be applied to Global Navigation Satellite System (GNSS) measurements taken by the mobile device over a long period of time while retaining the ability to produce highly-accurate location determinations for the mobile device. And additional correction information may be obtained and applied to the RTK correction information to extend this period of time even longer.

A differential global positioning system (DGPS) processor can include an almost fixed integer ambiguity (AFIA) module for generating in real-time a multiple dimensional state vector of integer ambiguities and multiple dimensional corrections. The AFIA module can use double difference (DD) measurements for pseudo-range (PR) and carrier phase (CP) pairs generated from at least three global positioning system (GPS) receivers. A DGPS processor can be included in a high data rate real time attitude determination (RTAD) system to achieve high heading accuracy with high integrity.

The present disclosure relates to a robotic working tool system comprising a robotic working tool (1), and navigation means enabling the robotic working tool to navigate within a working area (3) defined by a working area boundary (13). The navigation means comprising a base RTK unit (9), adapted to be stationary during operation of the robotic working tool (1), a mobile RTK unit (11), adapted to move with and provide positioning data to the robotic working tool (1), and a recording RTK unit (11, 9, 17) which is separate from or separable from the robotic working tool (1) to be moved along a path (15) to record position data corresponding to the working area boundary (13) independently of the robotic working tool (1), and to transfer the position data to the robotic working tool (1).

The present disclosure relates to a robotic working tool system comprising a robotic working tool (1), and navigation means enabling the robotic working tool to navigate within a working area (3) defined by a working area boundary (13). The navigation means comprising a base RTK unit (9), adapted to be stationary during operation of the robotic working tool (1), a mobile RTK unit (11), adapted to move with and provide positioning data to the robotic working tool (1), and a recording RTK unit (11, 9, 17) which is separate from or separable from the robotic working tool (1) to be moved along a path (15) to record position data corresponding to the working area boundary (13) independently of the robotic working tool (1), and to transfer the position data to the robotic working tool (1).