Abstract: A method may include sending a first message to an additional processing circuitry, the first message including a first time associated with a transmission of a second message; and sending the second message to the additional processing circuitry. The method may involve determining a second time associated with a reception of a loop-back message and a first loop-back timing delay based on the first and second times. The method may involve receiving a third message from the second control circuitry, the third message having a third time associated with a transmission of a fourth message. The method may determine a fourth time associated with a reception of the fourth message, the fourth message including a fifth time. The method may receive a second loop-back timing delay associated with the additional processing circuitry from the additional processing circuitry and determine an absolute time synchronization delay based on the times and delays.

Abstract: The present disclosure relates to a method to determine the phase of a signal when transmitter and receiver circuits use separate clocks. A discrepancy between the separate clocks is determined, as is a correction factor between the separate clocks. The phase is determined using a measured time of arrival of the signal, the determined discrepancy, and the determined correction factor. A drift factor and an expected start time of a pulse sequence may be used to determine the discrepancy. A start time of a pulse within the pulse sequence is determined and used to determine the correction factor. The method works by either absolute synchronization of the separate clocks, or by making the measurements independent of clock synchronization.

Abstract: The present disclosure relates to a method to determine the phase of a signal when transmitter and receiver circuits use separate clocks. A discrepancy between the separate clocks is determined, as is a correction factor between the separate clocks. The phase is determined using a measured time of arrival of the signal, the determined discrepancy, and the determined correction factor. A drift factor and an expected start time of a pulse sequence may be used to determine the discrepancy. A start time of a pulse within the pulse sequence is determined and used to determine the correction factor. The method works by either absolute synchronization of the separate clocks, or by making the measurements independent of clock synchronization.

Abstract: A system and method for steering a rotating downhole drilling tool is provided. The downhole tool includes an inclinometer having directional accelerometers capable of measuring drilling parameters, such as angular position and centripetal acceleration, of the downhole tool. An offset accelerometer is further included for determining centripetal acceleration of the downhole tool. Collar rotation rate and the toolface may be determined from the drilling parameters. Filters, analog to digital converters and processor devices may be used to process the signals and send commands in response thereto for steering the tool.

Abstract: A system and method for steering a rotating downhole drilling tool is provided. The downhole tool includes an inclinometer having directional accelerometers capable of measuring drilling parameters, such as angular position and centripetal acceleration, of the downhole tool. An offset accelerometer is further included for determining centripetal acceleration of the downhole tool. Collar rotation rate and the toolface may be determined from the drilling parameters. Filters, analog to digital converters and processor devices may be used to process the signals and send commands in response thereto for steering the tool.