---
title: "session(_:didUpdateDLTDOA:)"
framework: nearbyinteraction
role: symbol
role_heading: Instance Method
path: "nearbyinteraction/nisessiondelegate/session(_:didupdatedltdoa:)"
---

# session(_:didUpdateDLTDOA:)

Provides device ranging estimates for a Downlink Time-Difference-of-Arrival session.

## Declaration

```swift
optional func session(_ session: NISession, didUpdateDLTDOA measurements: [NIDLTDOAMeasurement])
```

## Parameters

- `session`: The session that provides a Downlink Time-Difference-of-Arrival measurement.
- `measurements`: The measurement updates for the session.

## Discussion

Discussion The framework invokes this callback to provide measurements for sessions that run NIDLTDOAConfiguration.