Abstract: The present disclosure relates to methods and apparatuses for reducing propagation delay uncertainty while conducting a survey. The apparatus includes a plurality of nodes along a communication path configured to allow communication between nodes with only one clock domain boundary crossing. Each node may include a clock, a memory, and a processor. The plurality of nodes is arranged in a linear topology. The linear topology may have first and second nodes on the ends of the line. The method may include reducing propagation delay uncertainty using at least one time marker transmitted to each of the plurality of nodes without crossing a clock domain boundary of any other node.

Abstract: The present disclosure relates methods and apparatus conducting a seismic survey while supplying power and data over multiple conductor pairs. In aspects, the disclosure also relates to maintaining power distribution during a failure of at least one conductor pair. The method includes superimposing data and power on each of a plurality of conductor pairs. The apparatus may include a power supply with power supplied by the plurality of conductor pairs carrying power and data.

Abstract: The present disclosure relates methods and apparatus conducting a seismic survey. The apparatus includes an analog interface and power supply both disposed in a housing. The analog interface is configured to receive analog seismic data from a seismic sensor. The apparatus includes one or more of: (i) an isolation transformer disposed between the power supply and the analog interface and (ii) a analog interface clock configured to synchronized with a power supply clock. The method may include reducing power transmission losses and/or the effect of power supply noise on the seismic signals.

Abstract: The present disclosure relates methods and apparatus for conducting a seismic survey using a fiber optic network. The method may include synchronizing a plurality of seismic devices over a fiber optic network where at least one of the seismic devices is separated from a master clock by at least one other seismic device. The method may also include encoding the master clock signal, transmitting the encoded master clock signal, and recovering the master clock signal. The apparatus may include a fiber optic network with seismic devices. The seismic devices may be arranged in a linear or tree topology.

Abstract: A system for acquiring seismic information may include a seismic spread in signal communication with a central controller having a central recording system, a source encoder in signal communication with the seismic spread, and a source decoder in wireless signal communication with the source encoder. The source decoder and the encoder are each selectively responsive to a control signal and can be selectively configured to transmit the control signal.

Abstract: The present invention utilizes signals such as interrogate commands generated from a Master Clock or other High Precision Clocks in a distributed sensor data acquisition system featuring a communications network (such as a land/transition zone seismic data acquisition system) to stabilize the oscillator (timing cycle) frequency of Remote Clocks elsewhere in the network. The disclosed invention is characterized by the utilization of highly stable timing signals from a Master Clock or other High Precision Clocks as a calibration standard to improve the oscillator frequency of distributed Remote Clocks of lesser inherent stability. Implementation of the disclosed invention results in improved synchronization of seismic amplitude data concurrently acquired over a wide area and improved subsurface geologic resolution.