A spirit's Search power (SR6 p.227-228) works well enough locally, but distance in kilometers adds to the target number for the spirit's Magic + Intuition test, so it won't let you find someone in another sprawl.
Ritual spellcasting using a viable Material Link (SR6 p.144-145) doesn't have any distance limitation, but the Remote Sensing ritual (SR6 p.146) doesn't work with a Material Link; it requires a Spotter. The only ritual in the core rulebook with the "Material Link" keyword is Curse (SR6 p.145).
To locate a target with ritual magic and a material link, I think you have to use the Curse ritual to cast an Illusion on them, sustain the spell, and then use Astral Tracking (SR6 p.161) to follow that active link wherever it leads. It doesn't really matter which Illusion spell you choose, but tracing the link is an Astral + Intuition (5, 1 hour) extended test, so the target will likely have an hour or two before you reach them to dispel your illusion or set an ambush. If you choose something subtle, like a Mask spell to make a negligible change in their appearance, they may not notice until it's too late.
