Anti-jam antennas advance aboard army observation vehicles

November 6, 2018  - By
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NovAtel’s GPS Anti-Jam Technology (GAJT) now rides into battle and military exercises aboard the Canadian Army’s Artillery Observation Post Vehicles (OPV) that have been fitted with the GAJT‑710ML antenna.

OPVs are highly mobile vehicles that perform observation, reconnaissance and patrolling missions, surveying and acquiring strategic targets and relaying instant, accurate target coordinates acquisition to artillery fire command systems. With their exposed position on the frontlines of the battlefield, OPVs can encounter severe GPS jamming aimed at crippling their capabilities. OPVs require reliable Position, Navigation and Timing (PNT) not only to safely and effectively navigate on the battlefield, but to provide reliable information to artillery in the rear.

GAJT provides protection for GPS navigation and precise timing receivers from intentional jamming in electronic attacks, ensuring that the satellite signals necessary to compute position and time are always available.

“GAJT allows us to have confidence that the position information from the GPS constellation is assured.” said Major Mike Moulton, the project manager in the Directorate of Land Communication Systems Program Management.

NovAtel’s GAJT is a retrofittable system. A military-off-the-shelf (MOTS) product, it comes in versions suitable for land or sea applications and smaller platforms such as unmanned aerial vehicles (UAVs). The antenna works with an array of military and civil receivers, including the Army’s handheld Defense Advanced GPS Receiver (DAGR), other military receivers using SAASM and M-Code, and with civil receivers.

“GAJT scrubs off unwanted signals. It differentiates between what we can recognize as a signal coming from a satellite and something anomalous, which could be interference or deliberate jamming,” explained Peter Soar, NovAtel’s Business Development Manager for defence. “GAJT does not contain a GPS receiver, but works with the receiver that’s already installed. So GAJT faithfully passes the good satellite signals to the receiver which then operates functions such as integrity monitoring in its normal way. GAJT is in use operationally and has been shipped to 16 allied nations around the globe.”

GAJT is a null-forming antenna system that ensures that satellite signals necessary to compute position and time remain available. There is no need to replace the GPS receiver that’s already installed, as GAJT works with both civil and military receivers operating in the GPS L1 and L2 bands. It is ready for M-Code, is a non-ITAR product and is readily available to authorized customers.

Trials with the Canadian Army’s testing unit validated the technology, maintaining access to the GPS signal in an adverse signal environment. It also gave NovAtel engineers a detailed unclassified report on the trial findings and recommendations. The feedback helped NovAtel modify GAJT into a stronger product. The GAJT-710ML antennas were delivered earlier this year, and the Army worked with General Dynamics Missions Systems Canada, the prime contractor for the mission systems on the OPV, to integrate the antenna aboard the vehicle.

“GAJT is a Canadian success story. It is 100 percent produced in Canada and sourced from Canadian components. I think that the Directorate of Land Communication Systems Program Management have shown there is excellent technology in Canada that can be leveraged to meet the Army’s requirements in a very rapid manner,” added Moulton.

This story uses some quotes that first appeared in “Out of a Jam,” an article by Chris Thatcher in Canadian Army Today.


Image: NovAtel

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