I am working on a project involving iBeacons. I am observing that the didRangeBeacons method is called in 1 second interval. Is there any way to reduce this time interval? My project requires low latency proximity detection and I was wondering how this could be achieved.
No, you cannot reduce this interval on iOS because it is baked in to the CoreLocation APIs. You can do so on Android, or you could do something similar with lower-level CoreBluetooth APIs on iOS, but using CoreBluetooth is a bigger roll-your-own project than can be answered here.
While I am unsure of your use case, you should consider that reducing the interval might not help. Beacons only send out advertisements at a certain frequency (typically 1-10Hz). If you are using a beacon transmitting at 10Hz, you could potentially get a detection in 1/10 of a second. But if you need a distance estimate, this fluctuates greatly with each packet, so you really need to average the measurements over many samples anyway.
Also, consider that a CoreBluetooth-based solution would only be able to do faster ranging when the app is in the foreground. Background processes on iOS have a whole different set of delay challenges.
Finally, any CoreBluetooth solution could not work with standard iBeacons because iOS sandboxes the ability to read iBeacon identifiers with anything other than CoreLocation. So you would need to build a custom beacon.