Dual-Clock Timing Solution for Ocean Bottom Node Acquisition

As seismic surveys increasingly rely on autonomous Ocean Bottom Nodes (OBNs), extending mission duration requires low-power, high-precision timing solutions. Traditional oscillators like chip scale atomic clocks (CSAC) and oven-controlled crystal oscillators (OCXO) offer stability but consume significant power and eventually high cost. We present a dual-clock architecture combining a low-power TCXO with a high-stability reference clock activated intermittently. This design reduces power consumption while maintaining timing accuracy. A 60-day laboratory test across 10 nodes showed raw drift below 10 ms and residual timing errors under 50 µs after ideal 2nd order fit on continuous data, with no instability from clock switching. The dual-clock system offers a reliable, energy-efficient alternative to conventional solutions for long-duration Ocean Bottom Nodes (OBNs) deployments.