Passive Sensor Network Clock Synchronization via Centralized Server

The patent introduces a centralized server as an intermediary that performs the complex synchronization calculations. Instead of equipping each sensor with expensive atomic clocks or GPS receivers, the sensors simply record TOA measurements and transmit them to the server, which then computes the clock offsets and skews using iterative optimization processes. This mediator approach centralizes the computational complexity while keeping individual sensor units simple and inexpensive.

The patent replaces the physical hardware-based synchronization mechanisms (atomic clocks, GPS receivers) with a software-based computational approach. The synchronization is achieved through mathematical optimization algorithms that process TOA measurements, substituting the need for specialized hardware with algorithmic processing that can be performed on ordinary computers or servers.

The centralized server acts as an intermediary that handles the computationally intensive synchronization tasks. Individual sensors only need to perform simple TOA measurements and transmit data to the server, avoiding the need for power-intensive atomic clocks or GPS receivers at each sensor location. This distribution of computational load significantly reduces power consumption at the sensor level.

The patent substitutes power-consuming hardware-based timekeeping mechanisms with a low-power software-based approach. Sensors use ordinary clocks that consume minimal power, and the synchronization is achieved through data processing at a centralized server rather than through continuous operation of expensive, power-intensive hardware at each sensor node.

Instead of having sensors actively communicate with each other through two-way messaging or ranging, the patent inverts the approach: sensors passively receive signals from external sources and unilaterally transmit their TOA measurements to a centralized server. This eliminates the need for complex bidirectional communication protocols and sensors only need simple transmit capabilities.

The centralized server serves as an intermediary that collects TOA data from all sensors and performs the synchronization calculations. This eliminates the need for direct sensor-to-sensor communication, simplifying the sensor design while maintaining synchronization capability through the centralized coordination approach.

The patent converts the weakness of relying on external signals into a strength by using multiple independent signal sources (satellite signals and terrestrial signals from broadcast towers or cellular base stations). Instead of being vulnerable to jamming of a single GNSS constellation, the system can selectively use signals from multiple sources, and the iterative optimization process can identify and exclude jammed signals, turning the potential harm into a robust multi-source approach.

The patent changes the parameter of signal diversity by incorporating both satellite-based and terrestrial-based signal sources. This parameter change allows the system to operate in environments where GNSS may be jammed, as terrestrial signals provide an alternative source that is less susceptible to space-based jamming, thereby reducing overall vulnerability while maintaining positioning accuracy.