Patent ID: 11956744
Assignee: CRYSTAL INSTRUMENTS CORPORATION
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. In a distributed data acquisition system having multiple physically unconnected data acquisition units whose collected measurement data are timestamped using a satellite radio beacon positioning system, each data acquisition unit of the distributed data acquisition system comprising:
a receiver of transmitted messages from the satellite radio beacon positioning system, the receiver deriving a current absolute time from the messages and having a time register for storing the derived absolute time;
an analog-to-digital converter (ADC) having a control input coupled to a sampling clock, a data input receiving analog measurement data signals, and a data output providing sampled digital measurement data concurrent with sampling clock control signals from the sampling clock; and
a hardware logic circuit with a data input coupled to the data output of the ADC to receive the sampled digital measurement data therefrom and having a data output providing timestamped measurement data associating batches of sampled measurement data with timestamps with a sub-microsecond accuracy relative to a corresponding absolute time established by the time register of the receiver;
wherein a central host processor in communication to receive timestamped measurement data from each data acquisition unit is configured to compute a bias correction based on a comparison by the central host processor of a measured time from a time stamp of the measurement data with a corresponding nominal time based on a start time, nominal sampling rate of the clock, and number of data samples, and apply the computed bias correction to the timestamped measurement data.