November 18, 2023: In Gaza Hamas has retreated to its 500 kilometers of tunnels. Following them underground are the Israeli Yahalom Tunnel Warfare Troops. Tunnel warfare is nothing new and the Israelis have been involved it for as long as their enemies in Gaza and Lebanon have. Israel has developed some new technologies involving drills, improved sensors and night vision equipment as well as improved radio communications and other electronic tools. At the same time Israel has relied on work done by other nations with an interest in tunnel warfare.

Until recently the most intense work on tunnel warfare tech was by the United States and South Korea. For example, since 2019 both countries have been jointly developing the 4x4 electric powered ATE (Autonomous Tunnel Exploitation) robotic vehicle for exploring the tunnels that North Korea has built a lot of for storing weapons, moving troops or leading to underground weapons storage or manufacturing facilities. Some of the North Korean tunnel systems are extensive and some are protected by surveillance cameras and remotely controlled defenses. Some of the tunnels store hazardous materials. The Hamas tunnel system is very similar. Because of the hostages Hamas holds in the tunnels, Israeli tunnel specialists can’t simply blow up some tunnels.

The purpose of the ATE vehicle is to quickly, carefully and precisely explore these tunnels using a number of sensors to detect and identify what is down there while creating a 3D map of the tunnel or larger tunnel system. The prototype ATE was recently tested on a 1,500-meter South Korean test tunnel containing many of the characteristics of North Korean and Hamas tunnels. ATE did well and tests continue.

Military tunnels were extensively used during the 20th century wars and troops developed techniques for investigating tunnels, especially ones that were apparently unoccupied by hostile forces but might contain stores of weapons, ammo and other supplies or civilians taking refuge or held as hostages. Some troops had a talent for exploring these tunnels and not getting killed. These were the “tunnel rats”, who became obsolete with the introduction of PackBot in 2002 for bomb disposal and replacing tunnel rats with a remotely controlled UGV (Unmanned Ground Vehicle). In the 1990s the U.S. Army began exploring the small UGV concept but did not expect to have them in service until 2010 or later. September 11, 2001, changed all that. A year later PackBot showed up. Over 2,000 PackBots were used in Iraq, Afghanistan and elsewhere over the next decade and more than 5,000 were sold to military, police and first responder personnel during the same period. Updated PackBots are still, as of 2023, produced for military and bomb disposal users.

In 2011 the U.S. Army began using SUGV (Small Unmanned Ground Vehicle). This was a UGV developed by Teledyne with cooperation from the U.S. Army. SUGV development took over six years because PackBot was a hard act to follow. SUGV is also still in production, serving the same markets as PackBot and a growing number of competitors.

In 2011 the U.S. Army received the production model XM1216 SUGV robots. SUGV was the next generation infantry droid, replacing existing droids like PackBot. Before September 11, 2001, the army didn't expect to have robots like PackBot or SUGV until 2013. But the technology was already there, and the war created a major demand. The robots expected in 2013 were to be part of a new generation of gear called FCS (Future Combat Systems). SUGV was designed to use high tech FCS communications and sensor equipment, and, like PackBot, used off-the-shelf substitutes while waiting for the more ambitious versions the army was still developing. The troops didn't care, as long as it worked. These small robots proved to be quite rugged, having a 90 percent availability rate.

The overly ambitious, expensive and much delayed FCS program was canceled two years before SUGV was ready, but successful bits, like SUGV, were allowed to keep moving. This was a big deal for SUGV, because demand for these small droids collapsed when the Islamic terror offensive in Iraq did in 2008. There were plenty of droids left over for service in Afghanistan, where the Taliban provided a much lower workload for the little bots than did Iraq.

SUGV is a 13 kg (29 pound) robot, similar to the slightly larger Packbot. SUGV can carry 3 kg (6.6 pounds) of gear, and seven different "mission packages" are available. These include various types of sensors and double-jointed arms (for grabbing things.) SUGV is waterproof and shock resistant. It fits into the standard army backpack and is meant to operate in a harsh environment. The battery powered SUGV is operated wirelessly, or via a fiber optic cable, using a controller that looks like a video game controller with a video screen built in. SUGV can also use an XBox 360 controller, with the right drivers. Like PackBot, SUGV can climb stairs, maneuver over rubble and other nasty terrain.

The SUGV design is based largely on feedback from combat troops. For example, it is rugged enough to be quickly thrown into a room, or cave, activated and begin sending video, as well as audio, of what is in there. This feature makes it very popular with the troops, who want droids with the ability to see, hear and smell more acutely. No one likes being the first one to go into dark, potentially dangerous, places. Throwing a grenade at first doesn't always work, because sometimes frightened civilians are in there. Despite all these fine qualities, the current generation of robots is not fast enough, agile enough or sensitive enough to compete with human troops doing this kind of work. Sometimes, however, robots are an adequate, and lifesaving, substitute. SUGV is supposed to be better at this sort of thing.

SUGV can also perform outpost and listening post work. These are two dangerous jobs the infantry are glad to hand off to a robot. Outposts are, as the name implies, one or two troops dug in a hundred meters or so in front of the main position, to give early warning of an enemy attack. A listening post is similar, but the friendly troops are often much deeper into enemy territory. The SUGV battery enables it to just sit in one place, listening and watching, for eight hours or more. After that, you send out another SUGV with a fresh battery, and have the other one come back for a recharge. No risk of troops getting shot at while doing the same things, and the troops really appreciate that. Again, the problem with this is that the robot sensors are just not there yet. The sensors are getting close, but not close enough for troops to trust their lives to this thing.

Other dangerous jobs for the SUGV are placing explosives by a door, to blow it open for the troops, or placing a smoke grenade where it will prevent the enemy from seeing the troops move. Ever since PackBot reached the troops, users filled military message boards with interesting uses they have found for these robots, and new features they could make use of. SUGV is the product of all that chatter.

By 2012 the Department of Defense owned about 6,000 small robots. Most of them were in the army, and a little over half were in a combat zone. There would be a lot more of these small robots out there if they were a bit smaller and had better sensors. Because of this, efforts to have the infantry regularly use the small robots in combat have not been successful. The older 19 kg (42 pound) Packbots and 50 kg (110 pound) Talon were fine for dealing with roadside bombs, but too big and heavy to easily haul around the battlefield. But most troops admitted that if the small droids were a bit smaller and lighter and had better situational awareness, as in the ability to sense what was around them, they would be more welcome.

Tens of thousands of troops have combat experience with PackBot and Talon, at least in bomb disposal work. A growing number of troops have used the small robots for security jobs, and combat work. The smaller and more compact SUGV shows how quickly new generations of these droids can be turned out. It was expected that by the 2020s several new generations of droids, and more powerful sensors and software, would be available. ATE is one of these future UGVs. The droids will never have the same senses, like sight, hearing, smell and vibrations that humans do, but they are acquiring similar senses that are useful enough. These are becoming more powerful, and a new generation of data analysis software makes it possible for near-future droids to quickly interpret what they sense and let their operator know, quickly, that there is something out there, and approximately where it is. Eventually it was expected that droids would be able to rotate its sensors like a camera or thermal sensor around to give the operator a better look at what it heard or felt. Smell was expected to take a little longer, and a version of that is present with ATE. By the 2020s droids were expected to operate on their own a lot and respond to voice commands. Again, ATE implemented a lot of these items. Ultimately the infantry wants small droids that hostile forces won't be able to sneak up on. That's the sort of bot the troops want to go into action with. And at that point, infantry units will have them as part of their basic equipment. It's that hope that kept projects like PackBot and SUGV going and produced more capable UGVs like ATE.