Test-AC
{{#switch: {{{model}}}
| #default =
Crash Detection
If Crash Detection is enabled, it monitors acceleration on each axis which helps to detect an accident. Threshold and Duration values are set depending on the impact magnitude that is required to be detected. {{{model}}} can detect events ranging between a slight tapping on the device and a severe accident. {{{model}}} will collect crash trace data with frequency defined by Trace ODR (Hz) parameter. Acceleration, GNSS and IO data monitoring duration during the crash event is defined by these parameters:
- Accel duration (s) - Acceleration data duration can be set for up to 15 seconds before crash event and 15 seconds after.
- GNSS duration (s) - GNSS data duration can be set for up to 30 seconds before crash event and 30 seconds after.
- IO duration (s) - IO data duration can be set for up to 30 seconds before crash event and 30 seconds after.
Crash Trace Modes
Disabled
- No crash trace is provided.
- When Crash Trace is disabled only one eventual crash record will be generated when Duration (ms) and Threshold (mg) values are exceeded.
Trace Changes
- Device will collect acceleration data for the configured period.
- When acceleration values are changed by more then 50mG data will be collected and records generated.
- If Acceleration does not change, records will be saved with 1 second period.
Trace Full
- Data tracked: Buffer size is calculated by the below provided formula. Trace Full mode will trace everything for the configured trace duration period, regardless if axes changed more than > 50 mG or not.
SampleFrequency (100 Hz) * TraceDuration (5 s before + 5 s after)
For example, if frequency is configured at 100 Hz, and the duration is set to 5 sec, the buffer will be created for 1000 entries, each containing X, Y and Z values. This buffer will be split into records. Records sharing the same crash counter correspond to the same crash event. To reconstruct the full trace, append the accelerometer data with the corresponding crash counter.
Note: With Crash Trace mode enabled, it is recommended to use Codec 8 Extended Data Protocol. This helps to optimize crash trace data sending from device to server. For more information, please visit Crash trace page.
Crash Counter
Crash Eventual record and Trace records can have a new IO element Crash Counter“ (AVL ID 317). In addition to Crash Counter, Crash Trace must also be enabled in order for the functionality to work. Crash Counter connects the eventual crash record with its trace packets meaning each eventual crash record will have ID 317, as well as that crash‘s trace packets with the same value. When enabled, first crash will send eventual record with value 1. Subsequent crashes will add 1 to value overflowing at 255 and starting again from 0.
Ground Vector
Ground vector must be removed from the magnitude used in the crash evaluation. Ground vector is calculated when AXL calibration is present, otherwise, it is not removed. Magnitude is recalculated when the device has no calibration. For that, it is supposed, that the required acceleration is on the XY plane. Then angle between the Z axis and the XY plane is 90 deg, therefore Pythagorean theorem can be used. If the magnitude is less than 1 G, the result cannot be evaluated and is set to 0.
Note: Each record will have accurate timestamps in milliseconds.
Crash Classification
| Crash Event Element ID | Value | Meaning |
|---|---|---|
| 247 | 1 | Crash detected, the accelerometer is partially calibrated |
| 6 | Crash detected, the accelerometer is not calibrated | |
| 7 | Crash (pothole) detected. Max Z axis | |
| 8 | Crash (fake) detected. Max axis X or Y, but without essential speed change | |
| 9 | Crash detected, the accelerometer is not calibrated | |
| 12 | Crash detected, the accelerometer is full calibrated |
Conditions for the fake crash detection:
- Device must have a GPS fix.
- Max crash axis is X or Y.
- Speed must be more than 0.
- Crash second speed value must be more than 0.
- Subsequent second GPS speed value must be greater than crash speed value minus threshold.
- Subsequent (2nd second) second GPS speed value must be greater than crash speed value minus threshold times two.
Example: if GNSS duration is set to 6 s and Accel duration is set to 5 s, there will be two records that will not contain accelerometer data. Crash records always contain accelerometer data for the duration of the Accel duration setting, regardless of I/O settings.
AVL IDs
| PARAMETER NAME | PARAMETER ID (RELATED AVL ID) | DESCRIPTION | VALUES |
|---|---|---|---|
| Scenario Settings | 111400 (247) |
Sets the scenario priority level. |
0 = Disable Disable scenario. |
| Duration (ms) | 11401 | Sets the minimal time period for how long the acceleration value should be higher than "Threshold" to trigger the event. | Minimum value = 0 Maximum value = 1000 |
| Threshold (mG) | 11402 | Sets the acceleration threshold value to detect the event. | Minimum value = 100 Maximum value = 6000 |
| Threshold (16 g) (mG) | 11416 | Acceleration threshold (applicable for devices with max 16 g range accelerometer) | Minimum value = 100 Maximum value = 14000 |
| Send SMS to | 7037 | Sets the GSM number of SMS event recipient. | Number selected from “GSM Predefined Numbers” list in menu “SMS / Call Settings”. |
| SMS Text | 8037 | Toggle filtering of accelerometer data in the crash trace. IF enabled, data is passed through EMA filter with 0.4 beta value (can be changed through serial command). | Maximum text length = 160 symbols |
| Trace Filter | 11412 | Toggle filtering of accelerometer data in the crash trace. IF enabled, data is passed through EMA filter with 0.4 beta value (can be changed through serial command). | 0 = Disable 1 = Enable |
| Crash Trace | 11406 (257) |
Enable tracing of crash events to get additional data about the crash. Related parameters: "Trace ODR", "Accel duration", "GNSS duration". | 0 = Disable Generates only an eventual crash record. 1 = Trace Changes Records timestamps, GNSS data and acceleration values ONLY WHEN acceleration values change my 50 mG or more (saves mobile data). |
| Crash Counter | 11415 (317) |
Toggle crash counter. This allows relating the eventual record of a particular crash with its trace packets by adding IO ID 317 to both. “Crash Counter“ and “Crash Trace“ must be enabled. The first crash will send an eventual record with IO ID 317 value 1. Subsequent crashes will add 1 to the value, overflowing at 255 and starting again from 0. | 0 = Disable 1 = Enable |
| Trace ODR (Hz) | 11410 | Sets the output data rate (frequency) of crash event data recording. | Minimum value = 20 Maximum value = 200/400
|
| Accel Duration (s) | 11407 | Sets monitoring duration of linear accelerometer values before and after crash event. This parameter is available for trackers without a gyroscope (IMU). |
Minimum value = 2 Maximum value = 15 |
| GNSS Duration (s) | 11408 | Sets monitoring duration of GNSS data before and after the crash event. | Minimum value = 2 Maximum value = 30 |
| Gyroscope crash trace | 78112 (1422) |
Gyroscope data is collected and processed simultaneously with accelerometer data. If enabled, collected data will be included in accelerometer + gyroscope crash trace, AVL ID 1422. This parameter is available for trackers that have a gyroscope (IMU) |
0 = Disable 1 = Enable |
| IMU trace duration before crash (s) | 78100 | Accelerometer and gyroscope crash trace duration before the crash. Sum of crash trace durations (before and after the crash) cannot be more than 20 seconds.
This parameter is available for trackers that have a gyroscope (IMU) |
Minimum value = 2 Maximum value = 15
|
| IMU trace duration after crash (s) | 78101 | Accelerometer and gyroscope crash trace duration after the crash. Sum of crash trace durations (before and after the crash) cannot be more than 20 seconds. This parameter is available for trackers that have a gyroscope (IMU) |
Minimum value = 2 Maximum value = 11
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