Navigation Voice Prompt Triggering
(Compiled by Hardy 2013, last reviewed 2021-01)
Principle
- Far-out prompts are simply triggered based on a lead distance threshold, derived by converting a meaningful lead time via the Default speed of the profile.
- Users can change the Default speed of the profile and it will affect the trigger distance for voice prompts.
- Note: The Default speed also affects the calculated route time
- Another way to change the voice prompt timing is to configure setting Arrival announcement. Check column Arrival setting further below to see which voice prompts will be affected. The trigger distance will be multiplied by the following factor
| Arrival announcement | Distance multiplier |
|---|---|
| Early | 1.5 |
| Normal | 1 |
| Late | 0.5 |
| In the last meters | 0.25 |
- For close prompts, both a distance threshold and a time threshold are used (see column Time threshold below). The time threshold ensures that the announcements are triggered early enough even if your current speed exceeds the Default speed.
- In addition, there is a user-configurable overall
VOICE_PROMPT_DELAY, particularly needed for output type Phone call audio, where we emulate a call to a car stereo which comes with a noticeable delay. (Also all distances to be used in the prompts anticipateVOICE_PROMPT_DELAY!) - We mute prompts immediately once they appear to refer actions already passed, or if your direction of travel seems no in line with a current route.
Base Profile Default Speeds
While these are now also user-adjustable, the defaults are
- Driving: 12.5 m/s (45 km/h)
- Cycling: 2.78 m/s (10 km/h)
- Walking: 1.11 m/s (4 km/h)
- Boat: 1.39 m/s (5 km/h)
- Ski: 1.39 m/s (5 km/h)
- Aircraft: 40 m/s (144 km/h)
Trigger Behavior
| Prompt type | Trigger time (sec) | Trigger distance (m) | Time threshold used | Arrival setting | Comment |
|---|---|---|---|---|---|
| Turn now | Driving: 7 s Cycling: 3.2 s Walking: 2 s | Driving: 45 m Cycling: 10 (12) m Walking: 4 (12) m | ✔️ | ✔️ | Dist for 3.6 s, min 12 m Time = max(8, sqrt(speed * 3.6)) |
| Turn in X m | 22 s | Driving: 275 m Cycling: 61 m Walking: 24 m | ✔️ | Skipped if less 15 seconds before turn | |
| Prepare to turn in X m | 115 s | Driving: 1438 m Cycling: 319 m Walking: - | Skipped if less 150 meters before "Turn in" Skipped if speed < 8 km/h | ||
| Long Prepare to turn in X m | 300 s | Driving: - Cycling: - Walking: - | Skipped if default speed < 108 km/h | ||
| Go Ahead | >300 s | Driving: 3750 m Cycling: 833 m Walking: 333 m | after route calculation if no other prompt is due, or after a turn if next turn is more than Long Prepare | ||
| Arrive at destination or intermediate | 5 s | Driving: 63 m Cycling: 14 m Walking: 6 (12) m | ✔️ | Min 12 m | |
| Approaching waypoint / favorite / POI | 60 s | Driving: 750 m Cycling: 167 m Walking: 67 m | ✔️ | ✔️ | Limit to max 1 pnt at a time |
| Passing waypoint / favorite / POI | 15 s | Driving: 188 m Cycling: 42 m Walking: 17 m | ✔️ | ✔️ | Limit to max 3 pnts at a time |
| Standard alarm | 12 s | Driving: 150 m Cycling: 33 m Walking: 13 m | ✔️ | ✔️ | |
| Close alarm | 7 s | Driving: 88 m Cycling: 20 m Walking: 8 m | ✔️ | ✔️ | Traffic calming uses pass alarm for approach prompt and filters duplicate in this radius |
| Off-route announcement | 20 s | Driving: 250 m Cycling: 56 m Walking: 22 m | ✔️ | Could be disabled | |
| GPS signal lost | 20 s | - | Is played after GPS signal has been lost for continuous 20 s and this was not caused by user action. |