Yes. PubNub delivers location updates in publish order per channel: each message carries a server-assigned, monotonically increasing timetoken, so a subscriber receives a device's updates in order without client-side sequencing.
Design for the real failure mode, which is a missed update rather than a reordered one. A subscriber that falls behind the publish rate, or that disconnects for longer than the subscribe buffer window, will miss updates. For live location that is often benign - the next update supersedes the last - but if you need a complete track, enable Message Persistence and replay from the last received timetoken on reconnect.
Techniques for handling a missed update may include (depending on the app requirements):
- Object position is interpolated when a gap is detected to provide for smooth movement (albeit at a possible time delay)
- Use a physics model for object movement whereby received messages adjust the model rather than the position directly
- Many, many other techniques used in gaming to overcome network and latency issues