This page explains how the Simacan platform registers the arrival and departure times at stops in the Control Tower. Simacan registers these times based on GPS data that we receive from the on-board computer. For more information about this, first read the article ''What is realization / GPS data?''
What is a Geofence
Simacan registers stops based on a so-called ''Geofence''. This is the area of measure X (adjustable) around a location. If the platform receives GPS positions in that area, we assume that the driver has 'arrived'. If we subsequently receive GPS positions outside that area, we assume that the driver has 'departed'.
Simacan works with an algorithm that then assesses when an arrival or departure has been realistic. For example, we prevent an arrival from being wrongly registered when the driver has only driven past a location.
A Geofence is generated by default for every location with a circle radius of X meters (configurable) around the center of the location. It is also possible to manually draw up a Geofence yourself. This allows you to make the area larger or smaller, for example. This is useful because you may be dealing with small stores or large distribution centers. For more information about drawing geofences, see location management.
Example of two automatically determined (i.e. not signed in) geofences close to each other. These can be made visible by selecting the setting 'Crumble path' in the trip details and zooming in far enough on the map:
Example of a manually drawn Geofence:
The stop detection algorithm is further explained below.
Start of a trip
Before a trip is actually considered ''started'', the platform waits for GPS data for the first stop. The driver must always be at the first stop before we can register the other stops.
After that, it is possible to drive stops in a different order than planned, provided this setting is enabled. It is of course preferable to keep the planning up to date with reality.
How is the arrival time determined?
As already mentioned, the arrival time is registered as soon as we receive GPS data within the Geofence.
In principle, the arrival time is: the first moment at which the vehicle comes to a standstill within the geofence (a so-called 'standstill_event'). The speed of the vehicle is then 0. Whether the presence of a vehicle within a Geofence actually leads to a registered arrival depends on a number of conditions:
- There must be several GPS points close to each other within the Geofence;
- The vehicle must remain within the Geofence for a minimum period of time. This length of time is a setting. For home delivery, for example, it can be set to 3 minutes (configurable). For transport operations with loading and unloading it will be a bit longer, like at least 10 minutes. Optionally, a minimum percentage can also be set of the planned stop time (or loading time) that must be spent within the Geofence. For example, is the driver standing still but moving again after 1 minute? We think the driver has not yet arrived.
- It contains 'capture' functions, such as that a very clear stop close to but outside a Geofence is also registered as a stop, under adjustable conditions;
- You can set whether or not stops may be registered in a different order (deviating from the planning);
- There is a 'time block' (Window) around the planned time of a stop within which it will be registered, these maximum 'too early' and 'too late' values can be set separately;
- Depending on the vehicle and on-board computer, turning off the vehicle's engine may also be considered as evidence of stopping; a so-called 'contact_off_event' or to the proof-of-delivery if available.
- The standstill start time is generated when a maximum of 100 meters has been driven within 3 minutes. The end time of a standstill is assigned to the first GPS point when the vehicle is moving again.
- If the standstill cannot be determined, there are fallback options such as the first detected point within the Geofence.
Below are explanations for problems that may occur with the stop detection in your Control Tower.
Problem: The departure is not registered
This does not happen very often, if the arrival is visible. Possible explanations why this occurs:
- The GPS may have failed during the stop, or the driver may have logged out, causing the connection to be broken.
- The driver is extremely early or late (although usually the arrival is also not visible).
- It concerns two adjacent (unloading) locations, where the driver stops his vehicle in the same parking space, so that only one stop is visible and it seems that the second has not taken place.
Problem: The departure is registered too early
Possible explanations why this occurs:
- This can happen if the driver briefly leaves the Geofence during a stop and then enters again, for example because of a break or because a detour is made between unloading and loading. This can be solved by drawing in Geofences more broadly and by properly setting the maximum 'too early' value.
- It can also be a result of 'GPS drift' where the location perception is inaccurate and fluctuating, while the vehicle is simply stationary. If a point falls outside the geofence, the stop will be wrongly completed. This risk can also be reduced by drawing in geofences (where possible).
Tip: Also read the article ''How ETAs are calculated''