“GPS unreliability” –Maritime Reporter & Engineering News – November 2020

A short explanation of why we need to get on with providing a terrestrial alternative to the GPS system by Dennis L. Bryant, Capt. USCG (retired).

Reportedly GPS can be spoofed for as little as $300.

With the Coast Guard’s increasing use of drones that use GPS navigation, its not unlikely drug smugglers will start spoofing GPS. We should be ready to detect such efforts and perhaps home in on them. Maybe need an inertial navigation alternative on our UAVs? (Not really sure what we are using right now.)

“Seeing Below The Surface: Ladar Trials Promise Enhanced Vessel Safety” –Maritime Executive

Ladar allows Color Line’s officers to perform safe deviation from the set course, maximizing fuel efficiency without increased risk of grounding.

Maritime Executive reports that,

Norwegian operator Color Line has been trialing Ladar, a light-based laser technology anti-collision system designed to identify floating objects on or under the surface of the water, including drifting fishing nets, logs, containers and ice, as well as plastic and other flotsam.

Wonder if this might be useful in finding people in the water, especially in rough weather and at night?

“The system we tested was better at detecting smaller items than we had anticipated, but not as good on metal objects in still water.”

The reason for this: waves caused by wind increase disturbance in the water around an object, making it easier to detect. “This includes up to storm level winds,” Dokken confirms. “The more activity in the water, the better.”

Frequently we need to go close to shore to execute a rescue. This could conceivably allow us to get closer without running aground, than we would using charts alone.

Might also be useful for the Waterways Commerce Cutters that operate in rivers with shifting bottom contours.

Really the Navy and Marines should be interested in this too.

Sounds like a good project for the R&D Center.

“Sonardyne’s New Forward Looking Sonar Supports Collision Avoidance” –MarineLink

Sonardyne Vigilent.  Compact in size and with mounting options for both new build and retro-fit. (Photo: Sonardyne)

MarineLink has an interesting press release concerning a forward looking navigational sonar. Since cutters must frequently depart established traffic areas and venture into shallower areas for SAR or law enforcement, this might be useful.

“Vigilant FLS offers mariners subsurface situational awareness, providing live and past vessel track, detailed 3D bathymetry out to 600 meters and automated warnings of unseen collision hazards on and beneath the waterline out to 1.5 kilometers.”

Target Designator, Perhaps Other Uses, Time for a New Alidade?

SOFRESUD “Intuitive Pointing Device” (IPD)

Looking at a new device caused me to consider how we might improve an old one, the Alidade.

SOFRESUD Intuitive Pointing Device (IPD)

NavyRecognition reports an innovation in target designation that might have some additional uses.

Performances are the following:
• Portable and mobile with full angular coverage
• Accurate and quick designation
• Day or night capability with digital zoom
• Data, audio and video recording and transmission
• All weapon and combat management systems compatible
• Optional on picatinny rails: counter-UAV & blinding non-lethal accessories

It is not really a firecontrol system, it’s an “Intuitive Pointing Device” (IPD). They refer to it as predesignation. It is really just a very sophisticated way to quickly and accurately input visual bearing and elevation, laser range, and image to a combat management system or remote weapons control station. This is seen as needed particularly for fast and/or stealthy targets and low-level surface or ground-based targets that can be seen but are difficult for radar to pick out of the clutter. Sounds particularly useful in the swarm attack scenarios the Navy has been so concerned about.

In its full configuration, the new IPD integrates many sensors to ensure all conditions capability:
– Extreme low light camera
– Uncooled IR camera
– Eye-safe laser rangefinder
– Fiber optic gyrometers
– Ambient microphone
– Display

Photo: “SOFRESUD’s IPD has a “slew to cue” capability when coupled with the remote weapon stations (such as a Nexter Narhwal or MSI Defence Seahawk) (or the Mk38 mod2/3–Chuck) vis the combat management. IPD operators can there steer and point the RWS to the exact location of the target. Optional equipment can be attached to the IDP thanks to picatinny rails: Sights, laser pointers, dazzlers…”

A Better Alidade:

I got to thinking about alternative uses for this device, including visual navigation, setting buoys, or just checking contacts for bearing drift. That, in turn, got me to think about our customary visual bearing determination device, the alidade. I don’t think they have changed since WWII.

Photo: 090113-N-9758L-040 PEARL HARBOR, Hawaii (Jan. 13, 2009) Quartermaster 3rd Class Mark Minick, assigned to the Pearl Harbor-based guided-missile cruiser USS Chosin (CG 65), looks through the telescopic alidade as the ship departs Naval Station Pearl Harbor during the Commander, Naval Surface Group Middle Pacific (MIDPAC) Surface Combatant Group Sail. (Original Navy description)

Our alidades have no low light level or IR capability or any way to measure distance. They have no electronic connection to pass either bearings or a picture of what is being looked at.

Wouldn’t it help the shipping officer in combat if he could get both an electronically transmitted visual bearing and a visual of a contact that would allow him to see the target bearing?

Visual navigation could be both quicker and more reliable if bearings could be quickly and reliably be passed electronically with the navigator able to confirm that the bearing taker is looking at the point the navigator intends.

The OOD or other bearing takers could benefit from a low light level or IR capability.

And off course the ability to point at air targets might be useful.


While the ergonomics of our alidades are very comfortable, there are potential problems with the IPD. Because it looks a lot like a gun, using it may lead to misunderstandings. There must be a protected place to put it down when not in use, but it is not illustrated. It’s probably too heavy to be used over long periods without some form of support.

If it were redesigned to rest safely on the gyro repeater and be used for bearing taking from there, it might solve some of these potential problems. Still to point to air targets you would want to be able to lift it off the stand, here a collapsible wire stock might be helpful.