Overview

Secure, reliable access to GPS has become a crucial part of warfare, with military forces like the Canadian Army relying on its accuracy in a variety of situations, including firing GPS-guided munitions from their weapon systems.

These munitions produce corrections that allow them to be guided with much more precision than a
ballistic-only shell, said Peter Soar, NovAtel’s Business Development Manager for Military & Defence. They are one of the many ammunition natures that can be fired by the Canadian Army’s M777C1 Howitzers to provide close fire support without sacrificing range, stability, accuracy or durability. The M777C1 is equipped with the Digital Gun Management System (an inertial navigation unit with an embedded GPS receiver) that enables the crew to bring the gun into action quickly and to engage targets precisely, particularly when employing precision-guided munitions.

While GPS offers many advantages during combat, including precision positioning that can be used to diminish collateral damage and to reduce the number of shots needed per mission, using this technology doesn’t come without its challenges.

“GPS signals are weak and vulnerable to interference, both accidental and intentional, making it critical to protect the GPS receivers from jamming that could lead to solution denial,” Soar said.

In the case of GPS-aided munitions, it is necessary to provide the shell’s GPS receiver with data about the GPS constellation before firing. This enables the receiver to acquire the GPS satellite signals within seconds of being fired. So although artillery guns like the M777C1 can be operated in conventional modes without GPS (using optical sighting techniques), when using GPS-aided ammunition it is essential to have a reliable GPS signal available at the gun.

GAJT 710ML NovAtel logo

NovAtel’s GAJT antenna offers a solution that helps ensure signal reliability. GAJT antenna systems protect against GPS interference by dynamically adjusting the antenna gain pattern and steering “nulls” toward the directions of interferers so bad signals are not amplified and good GPS signals still get through. This prevents interfering power from entering the GPS receivers, allowing them to acquire and track the satellite signals they need to function properly.

The Canadian Army trialed the GAJT-AE-N, the smaller of two GAJT form factors, late last year in live-firing conditions on the M777C1 Howitzer.

“The Army purchased the Howitzer for operations in Afghanistan,” Soar said. “It’s a versatile gun that can fire the heavy 155 mm ammunition while being tactically mobile. But for it to be most effective when using GPS-guided ammunition, it must have access to reliable GPS without the risk of falling victim to jammers.”

The trial was conducted at Canadian Forces Base Shilo in Manitoba with the support of the Build in Canada Innovation Program
(BCIP) of Public Services and Procurement Canada. The BCIP procures and tests latestage innovative goods and services within the Federal Government to help Canadian companies go to market.

This was the second time the Canadian Army tested GAJT technology with the support of BCIP. The first test, completed in 2014, evaluated the performance and usability of GAJT-700ML, the prototype that led to the operationally-fielded GAJT-710ML. GAJT proved its anti-jamming capability worked during that trial; the second test was designed to show that GAJT units could remain operational during live firing.

The most recent test demonstrated the technology’s robustness. The units remained intact even when exposed to the powerful shockwaves and vibration produced every time the weapon fired. The test was a “snapshot;” more qualification tests would be needed to field GAJT in this application. However, this excellent step, facilitated by the Government of Canada, helps NovAtel bring GAJT-AE-N to this market.

“I am proud to support Canadian companies via the Build in Canada Innovation Program, as administered by Public Services and Procurement Canada. Through our independent testing, we saw that NovAtel’s GAJT-AE-N continued to work under the most demanding circumstances,” GAJT Trial Director Captain Thomas Booth, CD said, “indicating it could potentially be employed to preserve a combat force’s freedom of action in a hostile and unforgiving environment.”

The detailed trials report, produced by the Canadian Army, will assist NovAtel in marketing GAJT to Allies.