An apparatus that performs spoof detection of satellite signals based on clock information derived from the satellite signals. The apparatus may include a position, velocity, time (PVT) component that derives the clock information from the satellite signals and provides the clock information to a spoof detection mechanism. In some embodiments, the clock frequency estimate is modeled as a Wiener process.

A probabilistic system for tracking a state of a vehicle using unsynchronized cooperation of information includes a probabilistic multi-head measurement model relating incoming measurements with the state of the vehicle. The first head of the model relates measurements of the satellite signals subject to measurement noise with a belief on the state of the vehicle, and a second head relates an estimation of the state of the vehicle subject to estimation noise with the belief on the state of the vehicle. A probabilistic filter of the system updates recursively the belief on the state of the vehicle based on the multi-head measurement model accepting one or a combination of the measurements of the satellite signals subject to the measurement noise and the estimation of the state of the vehicle subject to the estimation noise.

A probabilistic system for tracking a state of a vehicle using unsynchronized cooperation of information includes a probabilistic multi-head measurement model relating incoming measurements with the state of the vehicle. The first head of the model relates measurements of the satellite signals subject to measurement noise with a belief on the state of the vehicle, and a second head relates an estimation of the state of the vehicle subject to estimation noise with the belief on the state of the vehicle. A probabilistic filter of the system updates recursively the belief on the state of the vehicle based on the multi-head measurement model accepting one or a combination of the measurements of the satellite signals subject to the measurement noise and the estimation of the state of the vehicle subject to the estimation noise.

A process bus-applied protection system includes a process bus, a plurality of MUs (merging units), and a plurality of IEDs (intelligent electric devices). Each of the MUs is configured to sample a current and a voltage of a power system at timing synchronized with a time synchronization signal received through the process bus. Each of the IEDs is configured to be capable of outputting the time synchronization signal to the process bus by serving as a transmission source, and receiving, through the process bus, the time synchronization signal from another IED. The plurality of IEDs have a predetermined priority. Each of the IEDs is configured, when the IED does not receive the time synchronization signal from an IED having a higher priority than that of the IED and serving as a transmission source, to output the time synchronization signal to the process bus by serving as a transmission source.

A process bus-applied protection system includes a process bus, a plurality of MUs (merging units), and a plurality of IEDs (intelligent electric devices). Each of the MUs is configured to sample a current and a voltage of a power system at timing synchronized with a time synchronization signal received through the process bus. Each of the IEDs is configured to be capable of outputting the time synchronization signal to the process bus by serving as a transmission source, and receiving, through the process bus, the time synchronization signal from another IED. The plurality of IEDs have a predetermined priority. Each of the IEDs is configured, when the IED does not receive the time synchronization signal from an IED having a higher priority than that of the IED and serving as a transmission source, to output the time synchronization signal to the process bus by serving as a transmission source.

GNSS receivers and systems within such receivers use improvements to reduce memory usage while providing sufficient processing resources to receive and acquire and track E5 band GNSS signals directly (without attempting in one embodiment to receive L1 GNSS signals). Other aspects are also described.

GNSS receivers and systems within such receivers use improvements to reduce memory usage while providing sufficient processing resources to receive and acquire and track E5 band GNSS signals directly (without attempting in one embodiment to receive L1 GNSS signals). Other aspects are also described.

A method of receiving two chip-by-chip multiplexed CSK signals (e.g., GNSS signals) and searching for a non-CSK signal with optimal performance at a given digit capacity of a sampling memory resided in parallel correlators. For CSK signals Prompt, Early and Late results for each of possible code shift are calculated as different sums of four punctured convolutions. Depending on configuration, the method allows to receive both multiplexed CSK signals with lesser quality or one of the CSK signals with better quality. The method can be implemented as an apparatus with four punctured correlators, a set of multipliers by 1 or 2.sup.N, another set of multipliers by 1 or 0, summers of four input to one result, a RAM, searchers of maximum, and conditional commutators.

A method of receiving two chip-by-chip multiplexed CSK signals (e.g., GNSS signals) and searching for a non-CSK signal with optimal performance at a given digit capacity of a sampling memory resided in parallel correlators. For CSK signals Prompt, Early and Late results for each of possible code shift are calculated as different sums of four punctured convolutions. Depending on configuration, the method allows to receive both multiplexed CSK signals with lesser quality or one of the CSK signals with better quality. The method can be implemented as an apparatus with four punctured correlators, a set of multipliers by 1 or 2.sup.N, another set of multipliers by 1 or 0, summers of four input to one result, a RAM, searchers of maximum, and conditional commutators.

The presence or absence of a preamble is detected with accuracy in a reception apparatus that receives a signal including a preamble. A reception section receives a subframe including a subframe preamble and a message and a frame including a frame preamble. A processing section performs a process of detecting the presence or absence of the subframe preamble according to whether or not a given relation holds between a reception timing of the subframe preamble and a reception timing of the frame preamble. A message decoding section extracts the message from the subframe and decodes the message in a case where the presence of the subframe preamble is detected.