Crash trace

From Wiki Knowledge Base | Teltonika GPS

Introduction[edit | edit source]

This document describes the Crash Trace data and illustrates how to parse it. Two data examples are used. Understanding raw data / Parsing raw data.

The Crash Detection Scenario monitors acceleration on each axis to detect an accident. To parse it correctly, note that “Crash Trace” must be enabled, otherwise only one eventual crash record will be generated.

Understanding RAW data[edit | edit source]

When the “Crash Trace” is enabled, device will generate and send the accelerometer data in HEX format over AVL ID 257 (Crash trace data)

Alert.png
NOTE: Such RAW data is considered as a variable length value. Codec 8 Extended is required

Hexadecimal stream of AVL Data Packet receiving and response in this example are given in hexadecimal form. The different fields of packet are separate into different table columns for better readability and some of them are converted to ASCII values for better understanding.

Received data in hexadecimal stream:
00BDCAFE0120000F3335383X38303X3X3136383X34393X8E0100000178B0C1D4450100000000000000000000000000000000F70002000100F704000000000000000101010078001
D003F03F3001E003C03F30026004C04020022004603FD0023004603FC0024004803FC001F004303FB001F004103F10026004903FC0025004D03FF001E004303F70023004503FB001
F004103F6001C003B03F40022004703FB001E003B03F50025004A03FB001E003F03F30021004303FB0024004603FF01

Parsed:

AVL Data Packet
AVL Data Packet Part HEX Code Part
UDP Channel Header Length 00 BD
Packet ID CA FE
Not usable byte 01
AVL Packet Header AVL packet ID 20
IMEI Length 00 0F
IMEI 33 35 38 3X 38 30 3X 3X 31 36 38 3X 34 39 3X
AVL Data Array Codec ID 8E
Number of Data 1 (Records) 01
Timestamp 00 00 01 78 B0 C1 D4 45(GMT: Thursday, April 08, 2021 09:13:16 AM)
Priority 01
Longitude 00 00 00 00
Latitude 00 00 00 00
Altitude 00 00
Angle 00 00
Satellites 00
Speed 00 00
Event IO ID 00 F7
N of Total ID 00 02
N1 of One Byte IO 00 01
1’st IO ID 00 F7 (AVL ID: 239, Name: Ignition)
1’st IO Value 00 01
N2 of Two Bytes IO 00 00
N4 of Two Bytes IO 00 00
N8 of Two Bytes IO 00 00
NX of X Byte IO 00 01
1’st IO ID 01 01 (AVL ID: 257, Name: Crash trace data)
1’st IO data lenght 00 78
1’st IO Value 00 1D 00 3F 03 F3 00 1E 00 3C 03 F3 00 26 00 4C 04 02 00 22 00 46 03 FD 00 23 00 46 03 FC 00 24 00 48 03 FC 00 1F 00 43 03 FB 00 1F 00 41 03 F1 00 26 00 49 03 FC 00 25 00 4D 03 FF 00 1E 00 43 03 F7 00 23 00 45 03 FB 00 1F 00 41 03 F6 00 1C 00 3B 03 F4 00 22 00 47 03 FB 00 1E 00 3B 03 F5 00 25 00 4A 03 FB 00 1E 00 3F 03 F3 00 21 00 43 03 FB 00 24 00 46 03 FF
Number of Data 2 (Number of Total Records) 01


IO Value is considered as the accelerometer data.

NOTE: The crash data is packed in order as follows:
1.“X” Axis data
2.“Y” Axis data
3.“Z” Axis data
Every Axis data has 2 bytes data length info.

If you have any doubt about data packet structure, please refer to our Data Sending protocols

Processing “Crash Trace” data[edit | edit source]

Handling the Crash Trace data (AVL ID:257) as described in Understanding RAW data paragraph by axis order and data length, we will have:

Table 1. Axis values from AVL ID 257.

AXIS X AXIS Y AXIS Z
001D 003F 03F3
001E 003C 03F3
0026 004C 0402
0022 0046 03FD
0023 0046 03FC
0024 0048 03FC
001F 0043 03FB
001F 0041 03F1
0026 0049 03FC
0025 004D 03FF
001E 0043 03F7
0023 0045 03FB
001F 0041 03F6
001C 003B 03F4
0022 0047 03FB
001E 003B 03F5
0025 004A 03FB
001E 003F 03F3
0021 0043 03FB
0024 0046 03FF

Processing the “Crash Trace” data manually[edit | edit source]

As a brief example, here we have 6 axis values: Two from X axis, two from Y axis and two from Z axis. (Refers to “Table 1)

We will convert the HEX RAW data into the real axis value (mG)

001D 003F 03F3

x:29mG y:63mG z:1.011mG

001E 003C 03F3

x:30mG y:60mG z:1.011mG

Configuring the Crash Detection scenario[edit | edit source]

First, and according to technical details about AVL ID 257 (variable data length), run the Teltonika Configurator, go to “System” menu and chose “Codec 8 Extended” as the main Data Protocol, then go to “Accelerometer Features” menu and configure the “Crash Detection Scenario” according to your needs.
You can consult Crash Detection details at our Wiki Page.

700px-Crash Detection configuration example.png

The Parser[edit | edit source]

Crash Trace Parser The “Parser tool” consists in one editable sheet where the Crash Data must be entered. This should be done in the “C1” cell. Once you enter Trace Data, the parser will decode it automatically.

In cell A6 you’ll get the packet elements.
From cell A8 towards down you will get the samples count of axis packet. (“X” axis value, “Y” axis value and “Z” axis value)
In cell C8 towards down you´ll get the axis packet information
In cell D8 and E8 both towards down you will get all the axis “X” info (1byte per cell)
In cell F8 and G8 both towards down you will get all the axis “Y” info (1byte per cell)
In cell H8 and I8 both towards down you will get all the axis “Z” info (1byte per cell)

Crash trace Raw values.PNG

Parsing[edit | edit source]

After you insert the Crash Trace data in A1 cell, the parser will display processed info in mentioned cells. Note that all mentioned data is given in HEX.
Cell J8 towards down will show the converted HEX Crash Data into DEC (mG) data that belong to X Axis
Cell K8 towards down will show the converted HEX Crash Data into DEC (mG) data that belong to Y Axis
Cell L8 towards down will show the converted HEX Crash Data into DEC (mG) data that belong to X Axis

Parsing Raw samples.png

Graphing[edit | edit source]

As the Crash Trace data is inserted and processed by the own tool, the graph will be built automatically.

Crash Trace Sampling Graph.PNG