Grid protection keeps time by satellite. Jamming that signal is a federal crime, and it happens anyway.

Synchrophasor measurement, substation event ordering, teleprotection, fault location, and the timestamps on everything a utility later reconstructs — all of it leans on GPS timing. So do telecoms, broadcast, water SCADA and a great deal of process control.

Jamming or blocking that signal is illegal in the United States — to use a jammer, and equally to advertise, sell, import or market one — with penalties reaching $112,500 per violation and the possibility of criminal prosecution (FCC). The prohibition has not made the devices scarce: in a single month of 2011 the FCC issued 20 enforcement actions against online retailers in 12 states, covering more than 200 distinct jammer models, and returned in 2012 to sellers advertising on classified-ad sites (FCC enforcement).

The same interference that is grounding ships reaches these systems, and it does not need to target them. A jammer in a truck cab defeating a fleet tracker does not care what else is inside its radius.

Two failures, and only one has an alarm

A sensor fails. It reads out of range, stops reporting, or shows a diagnostic fault. Protection schemes are built for this and mostly handle it well.

A sensor lies convincingly. The reading is in range, the timestamp is plausible, the device reports healthy. Nothing trips, because nothing looks wrong. The automated response then acts on a number that is not true — and in protection and control, the automated response is the point.

What SENTINEL does in this setting

Judges sources against each other, not against a threshold. A reading that is individually plausible can still be inconsistent with every other source in the same interval. That inconsistency is the signal.

Counts participation explicitly. When timing degrades and sources drop out, the system knows it is operating on fewer inputs — and can be configured to require a minimum before an automated action is permitted at all.

Distinguishes "no data" from "data refused" from "nothing sent." Three different events that most historians record identically, and that mean three different things to the engineer reading back the interval.

Holds the automated action behind the record. Trip, close, shed, isolate, open a valve — the release is conditioned on the decision record for that interval being committed and verifying first.

Replays exactly. Same inputs, same record, byte for byte. For a post-event review or a regulatory filing, that is the difference between an explanation and evidence.

The compliance argument

Operators in this sector already live with evidentiary obligations — event reconstruction after a disturbance, audit trails for control actions, and a growing body of regulation asking not only what did your system do but why, and on what basis.

A tamper-evident chained record that accounts for every input in an interval — used, refused, late, or absent — is built for that question. It is not a log that was later pressed into service as evidence.

Who this is for

Transmission and distribution utilities with synchrophasor, teleprotection or automated switching schemes. Substation automation and protection-relay vendors who need a defensible story on GNSS dependence. Water, gas and process operators running automated safety actions on multi-sensor input. Telecom and data-centre operators whose timing chains have a single satellite dependency. Regulators and standards bodies writing GNSS-resilience guidance.

What it is not

Not a timing source. It does not replace a GPS-disciplined oscillator, an eLoran receiver or a rubidium holdover clock. It decides what to do when your timing and measurement sources disagree.
Not certified for protection duty. No IEC 61508 or equivalent safety case, no utility deployment, no type testing.
Not field-proven. Simulation only.
Not a granted patent. Four US provisional applications filed; none examined.

The condition that decides whether it helps

At least one source has to be genuinely independent of the one under suspicion. If every clock in the substation is GPS-disciplined, a single spoof moves them together and consensus tells you nothing. The first piece of work in any deployment is mapping what is actually independent — and that map is usually more interesting to the operator than they expect.

What we want from you

A recorded disturbance where the sources disagreed. That is worth more to us than a requirements document, and we will tell you plainly whether this would have helped.

info@rvappliedsystems.com · RV Applied Systems, Inc., Las Vegas, Nevada

Four US provisional patent applications filed. Patent pending; none examined or granted.