GNSS Jamming is the transmission of radio signals that disrupts
communications between tracker and satellites by decreasing the signal to noise ratio. When a device detects GNSS signal jamming, it activates the GNSS Jamming scenario. The device then generates and sends a record to the server, depending on hardware model activates Digital Output and optionally sends SMS notification to configured GSM number. After device regains GNSS signal, Digital Output is immediately deactivated and a new record is sent to the server. This Digital Output activation can be used to trigger measures to disrupt potential thieves using GNSS signal jamming to steal your vehicle. GNSS Jamming record is stored in '''AVL ID 318'''
parameter and has 3 possible values:
*'''0''' - No Jamming.
*'''1''' - Jamming warning status, which means that signal and accuracy is disrupted but device is able to hold GPS fix for at least 5 seconds.
*'''2''' - Jamming critical status, which means that device is not able to acquire GPS fix.
===<u> Introduction </u>===
It is important to note, that Jamming Detection can go from any state to any other in 1 second intervals. It is completely dependent on received NMEA data by GNSS receiver. Therefore, it is possible in repeated jamming scenario for the state to rapidly go from 0 to 2 and backwards. Also, GNSS Jamming functionality is capable to separate indoor areas (e.g. underground parking) from events when jamming is actually happening. This is possible because in-band jamming will affect internal PGA (Programmable Gain Amplifier) degrade, as a result, CNR (Carrier-to-noise ratio) will degrade as well. On the other hand, if CNR degrade is degraded only because of underground or signal covered, internal PGA gain will keep almost the same.
[[File:FTX SECO.png|right|500px]]
The purpose of Secure Engine Cut Off (SECO) is to bring a vehicle to a stop, in order to prevent unauthorized use. SECO disables the fuel pump, which would prevent the engine from continuing to run and stop the vehicle from being driven. For safety reasons, the system is designed to slow the vehicle down gradually in a controlled manner, ensuring that security measures do not compromise the driver’s or passengers’ safety. It is typically triggered by remote commands (SMS or GPRS) and is used for security or immobilization purposes.
Eventual Records parameter can be configured: when it is disabled scenario status value will appear in each AVL record, otherwise, it will be appended only to eventual records.
===<u>Prerequisites</u>===
From '''04.01.00.Rev.01''' Jamming Detection Delay parameter has been introduced. This parameter controls the time needed for the device to register a change in GNSS data to switch states.
*At least one '''DOUT''' is available.
*'''SECO functionality''' should have DOUT control priority higher than '''Immobilizer''' scenario.
===<u>How It Works</u>===
For example, with timeout set to a default value of 60, if GNSS is not being jammed, the device needs to register a jamming warning or jamming detected for 60 seconds for the device to consider jamming as ongoing (during this time, device can register warning and jamming states, this will not reset the counter). If no jamming is detected during the configured Jamming Detection Delay period at least once, the counter is reset to 0 and the countdown begins again.
Firstly, in order to safely slow down vehicle the systems toggles the relay, which is connected to fuel pump ('''GNSS Available'''). Secondly, at a safe speed, the system tuns on DOUT permanently in order to stop the vehicle ('''Speed Pulse'''). Last mode is activated in case no GNSS fix is available ('''GNSS Unavailable''').
===Additional Notes===
*GNSS Jamming is only available from '''03.28.03.Rev.03 or newer''' firmware version.
'''Speed Pulse'''
*GNSS Jamming is '''not available on 3.80, 3.82 but available on 5.10, 5.1.5, 5.1.8 or newer GNSS module firmware versions.''' GNSS module version can be checked by SMS\GPRS command – '''''getver'''''.
*This scenario will not work with [[{{{model}}}_Sleep_modes#Deep_Sleep_mode|Deep Sleep]], [[{{{model}}}_Sleep_modes#Ultra_Deep_Sleep_mode|Ultra Deep Sleep]] and [[{{{model}}}_Sleep_modes#Online_Deep_Sleep_mode|Online Deep Sleep]] modes.''' '''since they disable the device's GNSS module to save power'''.
DOUT control starts when the vehicle speed goes below a configured speed threshold and remains below this threshold for a specified speed check period. As soon as that happens DOUT is activated.
The timer will be reset if the vehicle speed increases above the configured speed threshold.
'''GNSS Available'''
This mode requires a GNSS fix to be present before DOUT control begins.
DOUT pulsing starts when the vehicle speed drops below a configured speed pulse threshold and the speed remains below this threshold for a specified speed check period.
'''GNSS Unavailable'''
This mode is used when a GNSS fix is not available.
In this mode, the system initiates DOUT control only if the vehicle is stationary, location data is unavailable, and the movement timeout condition is met.
'''Note:''' If there is no GNSS fix available and “secoon” command is sent, the system waits for the movement timeout to be reached before activating the configured DOUT. This approach ensures that the vehicle is stationary prior to disabling the fuel supply.
<td style="vertical-align: middle; text-align: center;"> Priority of how events are being sent to a server. For example, events with low priority are added to the periodical record, and events with high priority are sent immediately after they occur. </td>
<td style="vertical-align: middle; text-align: left;"> '''0''' = SECO scenario is '''disabled''' <br> '''1''' = SECO scenario is '''low''' <br> '''2''' = SECO scenario is '''high''' <br>
<td style="vertical-align: middle; text-align: center;"> Time span during which speed must be lower than configured for output to activate (GNSS on). </td>
<td style="vertical-align: middle; text-align: left;"> Minimum value = '''0'''<br> Maximum value = '''65535''' <br>Default value = '''10''' </td>
<td style="vertical-align: middle; text-align: center;"> Duration after which the DOUT will be activated if no movement is detected and GNSS is off. </td>
<td style="vertical-align: middle; text-align: left;"> Minimum value = '''0'''<br> Maximum value = '''65535''' <br>Default value = '''30''' </td>
<td style="vertical-align: middle; text-align: center;">Enables feature status sending only when the event happens (an eventual record). When disabled, feature status will be sent with both eventual and periodical records.</td>
<td style="vertical-align: middle; text-align: left;"> '''0''' = SECO status will be sent with both eventual and periodical records. <br> '''1''' = SECO status will be sent only when the event happens (an eventual record).</td>
<td style="vertical-align: middle; text-align: center;">Pulse functionality adds additional output control which helps to slow down vehicle before fully disabling fuel pump.</td>
<td style="vertical-align: middle; text-align: center;"> A value in milliseconds, for how long DOUT should be inactive. </td>
<td style="vertical-align: middle; text-align: left;"> Minimum value = '''10'''<br> Maximum value = '''5000''' <br>Default value = '''1000''' </td>
</tr>
</table>
<!---For Template:FTX SMS/GPRS Commands--->
{{#if: {{FTX Pin Support List|model={{{model}}}|pin=DOUT1}}{{FTX Pin Support List|model={{{model}}}|pin=DOUT2}}{{FTX Pin Support List|model={{{model}}}|pin=DOUT3}}
*Server or Domain address, either IP address or Domain can be written.
'''Port'''
*Server Port.
'''Data protocol'''
*TCP (Transmission control protocol) or UDP (User datagram protocol). Changing this parameter will alter how the device communicates. From the device side, TCP and UDP work almost the same, the only difference is that UDP doesn't need additional confirmation from the server side, that the data packet was received. TCP has that and uses more network data for the confirmation. The desired data transfer protocol can be selected through the configurator. For more information on the protocol differences of Teltonika devices, refer here [https://wiki.teltonika-gps.com/view/Teltonika_Data_Sending_Protocols]
----
'''New description added''' <br>
<span style="color:#00FF00;">'''Encryption'''
*TLS/DTLS are security protocols that protect information sent over a network by encrypting the data so only the intended recipient can read it. The protocols also help confirm that the devices communicating with each other are legitimate and ensure that the information is not changed while it is being transmitted. TLS/DTLS encryption creates a secure, private connection so sensitive data can travel safely across networks.</span>
----
===Secondary server settings===
'''Mode'''
*Backup - Records are sent to second server while main server is not available.
*Duplicate - records are sent to both servers (main and second), records are deleted from Flash storage only if both servers confirmed that the records were received from device..
{| class="wikitable"
|+ Secondary server parameters
|-
! Parameter !! Parameter ID !! Values
|-
| Second server type || 2010 || 0 - Disable, 1 - Backup, 2 - Duplicate
|-
| Secondary server IP or DNS address || 2007 || String
The Fuel Counter GNSS scenario provides fuel consumption estimation using GNSS-derived distance and user-configured fuel rate. It calculates the amount of fuel used by multiplying traveled distance by the average fuel rate and converting it to appropriate units. It is a software-based alternative when fuel flow sensors are not available.
<td style="vertical-align: middle; text-align: center;">Priority of how events are being sent to a server. For example, events with low priority are added to the periodical record, and events with high priority are sent immediately after they occur.</td>
<td style="vertical-align: middle; text-align: center;">The initial fuel counter value in litres. Can be used to set the starting value or reset the current one.</td>
<td style="vertical-align: middle; text-align: left;"> Minimum value = '''0.0'''<br> Maximum value = '''4294967.2''' <br> Default value = '''0.0''' </td>
</tr>
</table>
Latest revision as of 15:29, 5 June 2026
GNSS Jamming
GNSS Jamming is the transmission of radio signals that disrupts
communications between tracker and satellites by decreasing the signal to noise ratio. When a device detects GNSS signal jamming, it activates the GNSS Jamming scenario. The device then generates and sends a record to the server, depending on hardware model activates Digital Output and optionally sends SMS notification to configured GSM number. After device regains GNSS signal, Digital Output is immediately deactivated and a new record is sent to the server. This Digital Output activation can be used to trigger measures to disrupt potential thieves using GNSS signal jamming to steal your vehicle. GNSS Jamming record is stored in AVL ID 318
parameter and has 3 possible values:
0 - No Jamming.
1 - Jamming warning status, which means that signal and accuracy is disrupted but device is able to hold GPS fix for at least 5 seconds.
2 - Jamming critical status, which means that device is not able to acquire GPS fix.
It is important to note, that Jamming Detection can go from any state to any other in 1 second intervals. It is completely dependent on received NMEA data by GNSS receiver. Therefore, it is possible in repeated jamming scenario for the state to rapidly go from 0 to 2 and backwards. Also, GNSS Jamming functionality is capable to separate indoor areas (e.g. underground parking) from events when jamming is actually happening. This is possible because in-band jamming will affect internal PGA (Programmable Gain Amplifier) degrade, as a result, CNR (Carrier-to-noise ratio) will degrade as well. On the other hand, if CNR degrade is degraded only because of underground or signal covered, internal PGA gain will keep almost the same.
Eventual Records parameter can be configured: when it is disabled scenario status value will appear in each AVL record, otherwise, it will be appended only to eventual records.
From 04.01.00.Rev.01 Jamming Detection Delay parameter has been introduced. This parameter controls the time needed for the device to register a change in GNSS data to switch states.
For example, with timeout set to a default value of 60, if GNSS is not being jammed, the device needs to register a jamming warning or jamming detected for 60 seconds for the device to consider jamming as ongoing (during this time, device can register warning and jamming states, this will not reset the counter). If no jamming is detected during the configured Jamming Detection Delay period at least once, the counter is reset to 0 and the countdown begins again.
Additional Notes
GNSS Jamming is only available from 03.28.03.Rev.03 or newer firmware version.
GNSS Jamming is not available on 3.80, 3.82 but available on 5.10, 5.1.5, 5.1.8 or newer GNSS module firmware versions. GNSS module version can be checked by SMS\GPRS command – getver.
This scenario will not work with [[{{{model}}}_Sleep_modes#Deep_Sleep_mode|Deep Sleep]], [[{{{model}}}_Sleep_modes#Ultra_Deep_Sleep_mode|Ultra Deep Sleep]] and [[{{{model}}}_Sleep_modes#Online_Deep_Sleep_mode|Online Deep Sleep]] modes.since they disable the device's GNSS module to save power.
