GNSS Jamming is the transmission of radio signals that disrupts
[[File:FTX power saving settings.png|right|500 px]]
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'''
| ATC700
parameter and has 3 possible values:
| ATM700 =
*'''0''' - No Jamming.
[[File:ATX power saving settings.png|right|500 px]]
*'''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.
Puts the device into a power-saving mode, preserving the power consumption from the external source or the internal battery.
{{#switch: {{{model}}}
| #default =
| ATC700
| ATM700 =
}}
===Online Sleep===
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.
*In Online Sleep mode, the device manages the connection only when records need to be sent. The connection is opened at periodic intervals to send records and closed immediately after, without any timeout.
*Changing the Permanent Link setting during Online Sleep will wake up the device to apply the new configuration.
*With Permanent Link enabled, the device maintains a constant connection, sending records immediately as they are generated, rather than waiting for the next scheduled send. After sending connection remains open.
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.
<tr>
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.
*GNSS Jamming is only available from '''03.28.03.Rev.03 or newer''' firmware version.
*Configured '''Ignition source''' is off.<br>
*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'''''.
*Movement is not detected by the configured '''Movement source'''.<br>
*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'''.
*Device time must be synchronized, as this condition depends on the ''Record Settings -> Saving / sending mode'' parameter<br>
*After Position Fix - device time is synchronized with GNSS satellites and GPS fix is obtained.<br>
*After Time Sync - device time is synchronized over NTP, NITZ, or GNSS satellites.<br>
*Always - device will enter sleep mode without time synchronization and GPS fix.<br>
*Sleep timeout is reached.<br>
*No SMS messages are being received.<br>
*No open Data sockets (ignored with enabled permanent link)<br>
When device goes into sleep mode, some modules are turned off to consume less power. Listed below are the modules and scenarios that are turned off in common with all modes and those that are disabled specifically for the '''Power off sleep''' mode:
*Anything connected or enabled by BLE module(1 wire, DIN's, DOUT's, BLE as a peripheral)
</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.
