Harrison time pieces were indeed the cutting edge GPS technology of its day. That and moon watching. Nowadays we have GPS and Pulsar / Quasar watching. https:

Harrison time pieces were indeed the cutting edge GPS technology of its day. That and moon watching. Nowadays we have GPS and Pulsar / Quasar watching. https://en.wikipedia.org/wiki/Very-long-baseline_interferometry https://en.wikipedia.org/wiki/Very-long-baseline_interferome...