Implementation playbook
1. Threat model and coverage
Begin by mapping your GNSS infrastructure comprehensively: every antenna, cable run, receiver, timing server, and downstream consumer. Identify single points of failure where a compromised antenna or receiver could affect multiple systems. Assess your RF environment—are you in an urban canyon with multipath issues, near an airport with potential interference, or in a region where deliberate jamming or spoofing is a credible threat? Map your critical timing consumers and their accuracy requirements: does the trading floor need microseconds, or can the building access control system tolerate milliseconds?
Use this threat model to determine sensor placement priorities. Position GPSPatron probes to maximise detection probability and enable triangulation of interference sources. Cover high-value antennas first—those supporting critical systems or protecting multiple consumers—then expand to secondary sites as budget allows. If you have multiple antennas on a single roof farm, place at least one probe per antenna to detect localised spoofing attempts that might target specific receivers. Document your coverage map and any gaps that remain for future expansion.
2. Clocking and failover policy
Commission Meinberg grandmaster clocks with holdover specifications that match your service-level requirements. If you need one-microsecond accuracy for 24 hours during GNSS outage, specify rubidium oscillators. If you can tolerate ten microseconds for 8 hours, OCXO may suffice at lower cost. Configure multi-source reference selection policies that define which GNSS constellations to trust, when to fail over to PTP or NTP, and what conditions trigger holdover mode. If you have multiple grandmasters across sites, establish a reference hierarchy and cross-validation rules.
Document failover thresholds and test them regularly. What signal quality metrics trigger warnings versus alarms? At what confidence level do GPSPatron spoofing alerts cause GNSS isolation? How long can you maintain service in holdover before accuracy degrades beyond SLA? These parameters should be documented, validated in testing, and reviewed after any incident. Configure authenticated NTP and PTP where protocol support allows, preventing network-based timing attacks that bypass GNSS security measures.
3. Network path quality
Engineer deterministic timing domains across your network infrastructure. Identify critical timing paths between grandmasters and endpoints, and ensure these paths have reserved bandwidth and bounded latency guarantees. In complex networks with multiple switches and routers, this may require dedicated VLANs, quality-of-service policies, or separate physical timing networks. Measure your timing paths under load to verify that latency remains bounded and symmetric even during peak traffic.
Apply Relyum TSN switching where microsecond-class synchronisation must traverse complex or high-traffic networks, using time-aware scheduling to guarantee that timing packets are never queued behind bulk data. Use HSR or PRP where seamless redundancy is required—these protocols eliminate switchover time entirely by transmitting duplicate frames on parallel paths, making link failures invisible to timing consumers. Validate path quality with continuous monitoring and periodic test measurements using precision timing instrumentation, verifying that end-to-end accuracy meets requirements under all operating conditions.
4. Analytics and alert routing
Integrate GPSPatron GP-Cloud with your security operations centre, network operations centre, and SIEM platform using standard APIs or syslog. Define alert severity levels and routing policies that match your operational procedures: low-severity interference alerts might page facilities teams to inspect antennas during business hours, whereas high-confidence spoofing alerts trigger immediate grandmaster failover and wake SOC analysts at any hour. Configure alert context to include location, affected systems, threat classification, and confidence metrics so that responders have actionable intelligence immediately.
Establish response playbooks for each alert type with clear roles, actions, escalation paths, and success criteria. Who gets paged for each severity level? What immediate actions do they take? When do you isolate GNSS inputs versus continuing to monitor? When do you notify customers, regulators, or law enforcement? Document these playbooks and train relevant personnel on execution. Configure auto-actions where appropriate—for instance, automatically isolating a compromised GNSS input when spoofing confidence exceeds 90 per cent, or triggering antenna inspections when signal quality degrades below thresholds.
5. Prove it in lab
Before deploying your assurance architecture to production, validate the entire stack in a controlled lab environment. Use Teleplan Forsberg GNSS simulators to reproduce jamming, spoofing, antenna faults, and cable impairments under repeatable conditions. Verify that sensors detect and classify each threat type with acceptable accuracy and false-positive rates. Confirm that grandmasters fail over within specified timeframes and that timing remains within tolerance throughout events. Test your monitoring dashboards and alert routing to ensure that operators receive the information they need to respond effectively.
Run blue-team drills that train security and operations personnel on incident response procedures. Inject simulated threats while teams execute playbooks, measuring response times and identifying gaps in procedures or training. Capture quantitative evidence—detection thresholds, failover times, holdover accuracy, alert latency—to support accreditation and compliance documentation. Tune thresholds and policies based on lab results before go-live, and repeat validation testing after any significant configuration changes or software updates. Maintain a test schedule that ensures your assurance capabilities remain validated as threats evolve.
Response playbooks (examples)
Suspected spoofing at Site A
At 14:23 AEDT on a Tuesday afternoon, the GPSPatron sensor at Site A rooftop antenna detects anomalous constellation geometry combined with sudden carrier phase shifts. The on-device classifier analyses the signal characteristics and determines this matches a coherent spoofing profile with 92 per cent confidence. The sensor raises a HIGH severity alert to GP-Cloud, including RF signature data, affected GNSS constellations, estimated attack vector, and sensor location.
GP-Cloud correlates the Site A alert with telemetry from twelve other metropolitan sensors and determines that neighbouring sites show normal signal characteristics, suggesting a localised attack rather than regional interference. The platform generates a correlated alert: “Probable spoofing attack at Site A, confidence 92%, localised within 500-metre radius, GPS and GLONASS affected, originated 14:23:17 AEDT.” This alert routes to the security operations centre via SIEM integration and triggers an API call to the Site A Meinberg grandmaster.
The grandmaster receives the spoofing alert and executes its configured response policy. It pins the internal rubidium oscillator to holdover mode, immediately drops the compromised GNSS input from its reference selection algorithm, and fails over to a trusted PTP reference sourced from Site B grandmaster 15 kilometres away. NTP and PTP services distributed from the Site A grandmaster continue without interruption, now disciplined by rubidium holdover and the remote PTP source. Downstream systems experience no service disruption. The grandmaster logs the failover event with timestamps and reference quality metrics for post-incident review.
SOC analysts receive the correlated GP-Cloud alert on their monitoring dashboard and via SMS page. They open the incident ticket, review the RF signature and confidence metrics, and confirm that Site A has failed over to holdover as expected. Following the documented playbook, they block any new GNSS-dependent device onboarding at Site A until the threat is cleared, and they dispatch facilities personnel to physically inspect the rooftop antenna and surrounding RF environment for suspicious equipment or vehicles.
Facilities arrives at Site A within 40 minutes and conducts a visual inspection of the roof farm and neighbouring buildings. They identify no obvious sources but document the inspection with timestamped photos. The GP-Cloud telemetry continues to show spoofing signatures for another 15 minutes, then signals return to normal characteristics at 15:12 AEDT. The SOC monitors for recurrence over the next two hours, then authorises the Site A grandmaster to resume using GNSS references at 17:30 AEDT, with continued elevated monitoring.
Post-incident, the engineering team exports the captured RF signature from GPSPatron sensors and replays it in the lab using Teleplan Forsberg simulation. They validate that detection thresholds performed as designed and that failover timing met SLA requirements. The incident report includes complete forensic data, alert timeline, failover metrics, and grandmaster holdover accuracy measurements for compliance records. The security team briefs executive leadership on the event and response, noting that services remained within SLA throughout and that detection and failover automation worked as designed.
Progressive jamming near the roof farm
At 09:15 AEDT on a Thursday morning, GPSPatron sensors on a multi-antenna roof farm begin detecting gradual carrier-to-noise ratio (C/N0) decline across all visible GNSS constellations. Initial degradation is minor, 2 to 3 dB below baseline and the sensors raise a WARN severity alert indicating possible interference. Network operations centre staff receive the alert but take no immediate action, as WARN-level alerts typically indicate transient environmental conditions that resolve naturally.
Over the next 20 minutes, C/N0 continues declining. By 09:35 AEDT, signal levels have dropped 8 to 10 dB below baseline and constellation visibility is reduced. The GPSPatron sensors cross their ALARM threshold and escalate to HIGH severity, classifying the event as probable jamming based on the gradual onset, broadband characteristics affecting all constellations, and lack of spoofing indicators. GP-Cloud correlates sensor data and confirms that all six antennas on the roof farm show identical degradation patterns, suggesting a single interference source affecting the entire site rather than individual equipment failures.
The automated playbook triggers notifications to the facilities team via SMS and email: “HIGH: Probable jamming at Main Campus Roof Farm, all antennas affected, C/N0 degraded 8-10 dB, investigate RF environment for new interference sources.” Meinberg grandmasters at the site detect the signal quality degradation through their own receivers and automatically increase the weighting on rubidium oscillator holdover while continuing to track the degraded GNSS signals. Timing services remain within SLA as the grandmasters blend GNSS and holdover references according to their disciplining algorithms.
Facilities responds to the roof farm and conducts a visual inspection of the immediate area. They note that construction has begun on an adjacent building overnight, with new cellular equipment being installed on a tower approximately 50 metres from the roof farm. The timing aligns with the onset of interference. Facilities contacts the building management and confirms that a telecommunications provider installed a new 5G base station, which was activated for testing around 09:00 AEDT that morning.
The facilities team coordinates with the telecommunications provider to temporarily reduce the base station power while they investigate the interference. Within ten minutes of power reduction, GPSPatron sensors show C/N0 recovering toward baseline levels. The facilities team and telco engineers work together over the next two hours to adjust the base station antenna orientation, verify filter installation, and validate that spurious emissions are within regulatory limits. By 12:00 AEDT, GNSS signal quality has returned to normal and the sensors clear their ALARM status.
Throughout the event, Meinberg grandmasters maintained timing services within single-digit microseconds of UTC by blending degraded GNSS references with rubidium holdover. Downstream systems experienced no timing disruptions. The facilities team logs the incident with complete RF spectrum data captured by GPSPatron sensors, coordinates with the telco to implement permanent filtering and antenna adjustments, and schedules follow-up monitoring to verify the issue doesn’t recur. The engineering team updates the site documentation to note the new base station as a potential interference source for future reference.
What “good” looks like
Authenticity
Your detection system distinguishes between spoofing, jamming, multipath, equipment faults, and benign anomalies with high confidence and low false-positive rates. Alerts arrive with classification tags, severity ratings, affected constellations, estimated threat vectors, and forensic RF data that gives operators immediate context. Security teams trust the alerts enough to execute response procedures without spending hours investigating whether the threat is real. False positives occur rarely enough that alert fatigue doesn’t erode response discipline, but detection sensitivity remains high enough that real threats don’t go unnoticed.
Operators have visibility into GNSS health across all sites through unified dashboards that show constellation availability, signal quality trends, anomaly events, and threat classifications in real time. Historical data lets analysts identify patterns—recurring interference sources, equipment degradation trends, or attack attempts that probe defences. Forensic RF captures can be exported for detailed analysis or replayed in lab environments to validate detection thresholds and response procedures.
Availability
Timing and navigation services remain within defined tolerances during GNSS impairment thanks to robust holdover, reference diversity, and automated failover. When GNSS quality degrades or spoofing is detected, grandmaster clocks seamlessly transition to internal oscillators or alternative references without service interruption. Downstream systems continue operating normally while your team investigates and resolves the threat. Holdover performance is quantified and validated—you know precisely how long you can maintain accuracy during extended GNSS denial because you’ve tested it under controlled conditions.
Timing path redundancy ensures that network failures don’t become timing failures. Critical endpoints receive timing via diverse physical paths with automatic switchover, making infrastructure failures transparent to applications. You’ve engineered deterministic timing domains with bounded latency and reserved bandwidth so that timing packets traverse networks with predictable delay regardless of bulk traffic load. End-to-end timing quality is continuously monitored with alerting when path performance degrades below thresholds.
Observability
Comprehensive dashboards show timing offset trends, constellation health, signal quality metrics, alert history, failover events, and policy state across all sites. Operators can drill down from network-wide views to individual sensor telemetry, grandmaster reference selection details, or timing path measurements. Dashboards clearly distinguish between normal operations, degraded-but-operational states, and alarm conditions requiring response. Alert context includes remediation guidance so that first responders know what actions to take.
Timing quality data and assurance telemetry export to long-term storage with tamper-evident integrity, creating audit trails that support compliance and forensic investigations. When auditors ask about timing source integrity during a specific period, you can produce comprehensive evidence: signal quality metrics, constellation availability, alert events, failover actions, and accuracy measurements with cryptographic verification that the records haven’t been altered. This observability transforms PNT from a black box into a verifiable service with evidence-based assurance.
How iTkey helps
We design and deliver PNT assurance as an integrated system, not a collection of isolated products. The challenge isn’t finding individual components—it’s architecting those components into a coherent system that detects threats, maintains service, and produces evidence across diverse operational environments. That requires deep expertise in GNSS vulnerabilities, timing infrastructure, network engineering, security operations, and regulatory compliance.
We start by understanding your threat environment, timing requirements, and operational constraints. Where are your GNSS antennas, and what threatens them? What timing accuracy do your applications require, and for how long must you maintain that accuracy during GNSS denial? How do your security operations currently detect and respond to RF threats, and how will PNT assurance integrate with existing workflows? These questions shape the architecture we design.
GPSPatron sensors and GP-Cloud analytics provide early warning and threat characterisation, detecting spoofing and jamming before they affect services. Meinberg grandmasters deliver resilient timing infrastructure that maintains accuracy through GNSS impairment using disciplined holdover and reference diversity. Relyum network platforms preserve timing quality across complex distribution paths with deterministic transport and seamless redundancy. Teleplan Forsberg simulation validates your entire assurance stack under controlled conditions, generating the evidence that proves your defences work. Together, these components deliver trusted PNT with verifiable resilience and compliance-grade observability.
We deliver this as a turnkey service: threat assessment, reference architecture, equipment commissioning, policy configuration, integration with security operations, personnel training, and ongoing support. You get a complete PNT assurance system with documented procedures, validated performance, and evidence-based confidence that your timing and navigation will remain trustworthy through the full spectrum of GNSS threats.
Ready to strengthen your PNT resilience?
Share your antenna map, critical systems, and compliance targets with us. We’ll return a reference design showing sensor placement, grandmaster specifications, failover policies, and integration points with your security operations. The design will include a bill of materials with equipment specifications and costs, and a pilot plan that demonstrates measurable value within weeks rather than months.
If you’re facing regulatory questions about PNT integrity, preparing for compliance audits, or responding to emerging threats in your operational environment, we can help you build verifiable assurance that satisfies auditors and maintains service through GNSS impairment.