About location data

Timing of location data acquisition

• The AlterLock device acquires location when it detects an anomaly for the second or subsequent times after locking and when it sends a periodic transmission.
• If the AlterLock device is unlocked during positioning, the positioning is cancelled.
• The AlterLock device will start positioning after the device is completely stationary.
• The smartphone performs positioning when the device is locked or when Bluetooth is disconnected.

Not a single location information is displayed

Immediately after registering or re-registering a device, location information is not displayed because the location history has been cleared.

Location information cannot be acquired

Location information may not be acquired in the following cases.

If it is the first alarm after locking
If the alarm is triggered immediately after locking, the acquisition of location information may not have been completed.
AlterLock Gen2 acquires the smartphone’s location information as the location when locked, but location information may not be acquired due to problems with the smartphone’s signal environment or insufficient location authorisation for the application.
AlterLock Gen1 acquires location information on the device side when locked, but may not be able to acquire location information in environments where GPS signal reception is poor.

Indoors or underground where GPS signal cannot be received
In environments where it is difficult to receive GPS signals, such as indoors or underground, location information may not be acquired.
AlterLock Gen2 attempts to use Wi-Fi positioning when a GPS signal cannot be acquired, but Wi-Fi positioning may also fail if there are no multiple Wi-Fi access points nearby that can acquire location information.
Wi-Fi positioning uses the Google database.

If you are outside the Sigfox communication area or in a poor signal environment
AlterLock Gen1 and Gen2 transmit notifications and location information via Sigfox communication when outside the range of the Bluetooth connection.
Outside the Sigfox communication area or in a poor signal environment even within the area, the location information may fail to be transmitted.
In order to prioritise long-term battery operation, if communication fails, the device will not retransmit the information and will attempt to acquire and transmit the location information the next time it is detected.

Location information is not accurate

Location information may be misaligned in the following cases.

Errors due to GPS positioning
Indoors or in densely built-up environments, a sufficient number of GPS satellites may not be captured, resulting in deviations of several tens of metres.
Although very rare, deviations of up to 100 metres can occur when signals from GPS satellites can only be received from a limited number of angles.

Errors due to Wi-Fi positioning
Wi-Fi positioning uses information from multiple Wi-Fi access points in the vicinity to determine location information, but depending on the signals received by the access points, there can be an error of 50 to 100 metres.

Wi-Fi positioning shows a completely different location
Wi-Fi positioning with AlterLock Gen2 uses Google’s database, but the location information for Wi-Fi access points may not be registered in Google’s database or may be out of date.
In such cases, locations that are completely different from the actual location may be displayed.

Errors due to smartphone positioning
When the lock operation is performed or when Bluetooth is disconnected, location information is acquired from the smartphone as the last place of contact with the device.
Therefore, errors may occur depending on the distance between the smartphone and the device and the signal environment of the smartphone.

Acquisition of location information takes time

It takes between 20 and up to 90 seconds to acquire location information by GPS.
The first time the device detects movement after locking, it does not acquire location information and notifies the smartphone in the shortest possible time, in order to prioritise quick alerts; the second time the device detects movement, it starts acquiring location information after an alarm sounds. As it takes time to acquire location data, there is a delay of tens of seconds or more between when the alarm goes off and when the location data is notified.
AlterLock Gen2 waits until the device is stationary before starting to acquire location information in order to facilitate the identification of the device’s final location.
Therefore, location notifications do not occur while the device is moving, and location acquisition and notification occur when the device comes to a complete standstill.
Furthermore, a waiting period of approximately one minute is provided before the device detects movement for the third and subsequent times. Long-term tracking is achieved by not continuously acquiring location information.

Location information is not recorded

If location information is not recorded in the location history screen, there are several possible reasons.

• If the location information is not recorded at the specified interval, it is possible that the device failed to acquire the location information or that the data was not sent due to communication problems.
• The location information acquired when the device is locked or when Bluetooth is disconnected is temporarily recorded as the latest information on the device. If new location information is acquired, the past data will be updated and will not remain in the history.
• For more information on why location data cannot be acquired, please see ‘Location information cannot be acquired‘.

How to check the positioning method

You can check the positioning method from the icon displayed on the location information screen of the app.