DATA RECOVERY FOR PULSE TELEMETRY USING PULSE POSITION MODULATION

摘要

The specification discloses algorithms for error recovery in pulse position modulation-based mud pulse telemetry as show in figure 1. The system uses a mud pump (22) to generate a flow of mud through a drill string (10) which is modulated. The signal processor (28) detects and processes the received mud pulses. The algorithm detects and attemps to correct for at least five possible error mechanisms: the missed detection of a pulse that creates an interval greater than maximum; the missed detection of a pulse that results in an interval still within acceptable boundaries; the detection of an extra pulse; a pulse shift that results in data in contiguous intervals being affected; and a pulse shift resulting in a single interval data corruption.