The primary function of the GPSPATRON system is to detect anomalies in the navigation field caused by spoofing, interferences, or degradation of GNSS signals. However, users are only interested in obtaining accurate time synchronization of critical infrastructure in all cases. Subsequently, if some issues with GNSS signals are detected, it is indispensable to automatically switch to alternative sources of synchronization, or at least turn off the GNSS receiver and switch the time server to Hold Over mode.
There are various types of time servers, and here we utilize 3 mechanisms to integrate with it:
- GP-Blocker
- Automation scenarios in GP-Probe
- WEB API
GP-Blocker
All time servers are equipped with a high-stable local oscillator to provide an accurate clock if PTP or GNSS signals are unavailable. Therefore, the simplest way to protect against GNSS spoofing is to disable the GNSS antenna port and switch the time server to Hold Over mode.
| Advantages | Disadvantages |
| Ease to use
Just connect GP-Blocker to the time server antenna port. High reliability GP-Blocker has features to reliably block fake signals:
Read more about GP-Blocker in our article. |
For long duration incidents, the PPS’s error in Hold Over mode may exceed the accepted standards. You have to switch to the alternative synchronization source manually.
Example: the GPSPATRON detects Glonass jamming and disables the antenna port. After a few hours, the PPS error can reach microseconds. You will need to switch the time server to operate from GPS, BeiDou, or Galileo. According to our statistics, long time infringements are performed during public events or when VIPs visit key facilities. This is not a problem if it happens once or twice a year because GP-Cloud will advise of the beginning of the emergency event, and provide the time to make the compulsory arrangements. |
GP-Probe Automation Scripts
In case of the high probability of long duration events, manual control can be inopportune. Then it is feasible to use GP-Probe built-in automation tools and remote ports.
GP-Probe is equipped with Ethernet/RS232 ports and supports Telnet and SNMP protocols. Scenarios can be written and edited in a web interface of GP-Probe using Embedded Lua language.
When status changes, GP-Probe execute Lua script. Scripts provide current and previous statuses, find available GNSS systems, send control commands to the time server or other equipment.
| Advantages | Disadvantages |
| Flexibility
You can automate the control of any equipment, i.e., swap for other GNSS’ when spoofing or jamming. For example, you can switch to Galileo when GPS + Glonass is attacked, and then switch back when an assault is over. |
You have to write and test the automation script for each type of equipment. |
GP-Cloud WEB API
Use powerful REST API to integrate GPSPATRON into the synchronization management system. WEB API is well documented in Swagger. You can request information about the current state of the navigation field, as well as historical data. You could also use RabbitMQ to get instant notifications.
| Advantages | Disadvantages |
| High flexibility
You can automatically control the synchronization system and switch to trusted sources in case of event detection. This is the best way to integrate with existing infrastructure. |
You need to develop integration applications |
