GPS


Esli writes:

Out of extreme boredom, I recently read through some of XBrad’s archived material. (Yeah, I know.) This post , combined with this one got me thinking about my own early experiences with the GPS. We have all wondered why some people are seemingly so stupid that they follow their Garmin right into a river, down a boat ramp, or even off a cliff. At first it is incomprehensible, but I know better because I have seen it in action.

First, a little background. The army has always extolled the virtues of land navigation. Pretty much all NCO schools, officer commissioning sources, and certainly combat arms schools teach land navigation. Even though often someone else actually does the navigation, if a leader can’t navigate, he has a hard time leading (either figuratively or literally!). It is all about credibility.

Basically, you navigate in one of two ways. The first method is dead reckoning. In this technique, you know where you are, and if you walk a given distance and direction, you know where you will arrive.

The other technique, called terrain association, simply says to follow the terrain. For example, I walk up this trail to the fork, turn right 90 degrees, and head downhill to the creek, and then up the far side to the right-hand of two hilltops that I can see. Plot your new location and repeat. Skilled navigators combine the two techniques.

Mounted navigation adds a whole extra layer of complexity due to speeds and distances. After all, a dismounted infantryman may have been lost for an hour, but he is still only at most 2 km away! Tank navigation, pre-GPS, included neat tricks like pointing the main gun in a given direction and stabilizing it so that it would always point that direction. Then the driver could turn as necessary. As long as he turned back to get the main gun over his head, he was driving the right direction. Now, just watch the odometer. But, since compasses don’t work while on the tank, someone had to get down and walk out a way to get an azimuth. Pretty slow work.

Terrain association requires an understanding of the terrain, called “micro-terrain” that is all around you. This extends to vehicle crewman. For example, I should be able to tell my driver, “See that big hilltop on the horizon? Get us there.” From that point, his own form of land-navigation, called “terrain driving” takes over, and he follows the terrain, both to navigate, and to drive in the most survivable terrain (i.e. keeping in low ground, but not soggy ground with cattails growing in it), leaving me free to “lead the unit.”

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Mortar Platoon Leader. Working on the Battalion Command Net, the Mortar Platoon Net, and the Fire Support net is on the third radio that you can’t see at my feet. It is easy to get distracted, and a good driver can save you!

The GPS changed all of that. Appearing just in time for the Gulf War, the SLGR (Small Lightweight GPS Receiver and pronounced Slugger) revolutionized navigation. A more capable and widely-fielded variant, called the PLGR (or Precision Lightweight GPS Receiver or Plugger) was fielded in the mid -90s. The PLGR has been largely supplanted by the DAGR (the Defense Advanced GPS Receiver, or Dagger). But these items were not fielded without a learning curve by the force. The primary lesson of which is that a GPS does not replace a map!

So, how do they result in tanks driving into the river, down the boat ramp or off the cliff? A couple quick stories illustrate.

There I was…. It was 1994. I had just deployed to Kuwait and met with my first tank platoon, which was already there (Vigilant Warrior, Craig). I brought with me a box of 58 PLGRs as initial issue for the battalion. A couple of the “Geek-smart” platoon leaders quickly learned how to use them, but I was a bit slower. One day, we conducted a training lane consisting of a company attack. I followed in the right rear of a company wedge for about 20 Km. During the movement, I had limited success with my GPS, but had been so fixed on it that I had not used the map much. After the end of the mission, we went back to the assembly area to re-run it, at which time my CDR designated my platoon to lead the next run. I was pretty sure that I knew where I was, but had no idea how to get back to the objective for the next run, so I did what any quick-thinking tanker would do. When I rolled into the assembly area, I did a tight enough 180 degree turn that I got back on my own tracks in the sand. When we were ordered to move out for the next run, I unerringly led the company straight to the objective of the company attack. Score one for credibility.

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You tell me how to navigate through this “trackless” desert without GPS! (XBrad: LORAN-C?)

A few months later, there I was…again. This time, I was at Fort Irwin, the National Training Center. It was about midnight. The commander of the infantry company I was attached to drove up to my tank, threw me a six-digit map grid, and told me to establish a screen line “now.” I alerted the platoon, we got fired up, and moved out promptly, heading directly for the grid I was given. This turned into one of the most torturous night movements I have ever been on, taking about 3 hours to move 3 Km to the east and including a near-rollover into a wadi and the blowing away of something into the night sky that I saw but never figured out what I lost. This was across what NTC insiders call “the washboard” which is a nightmare of up and down, washes, cuts, wadis, etc. In the morning, when I was called to collapse the screen and link up with the unit, it took me all of 15 minutes to look at my map, drive south into the open maneuver corridor, and link back up with the company. Score one for the GPS, but credibility took a big hit here! Never move without looking at the stupid map first….

Fast forward a year to my next NTC rotation where I was now the mortar platoon leader. While driving to the Tactical Operations Center to receive an order from the battalion, I called the platoon and gave them a six digit grid and told them to move there and establish the next firing position. I would link up with them at the firing point after the order. I drove to them and discovered the whole platoon sitting in the wide open, within 100 meters of a perfect defilade firing position (that is, below ground level due to the terrain). They had, I was told, just moved to the grid I gave them, following the GPS to the end…. Amid much grumbling, I directed them to shift to the new position and passed on a lesson -learned about not just following the GPS. Score one for credibility.

The very next mission, I again moved them to a new position while I was gone, this time on “Crash Hill” and in the dark. I drove up to the hill, straight to the grid I had given them. They were not there. I drove around that hillside for 60 minutes, searching that location, getting progressively more and more angry. For some reason, I ripped the wooden roof from my HMMWV and flung it into the dark and the wind whipped it away. Finally, sitting right on the grid that they were supposed to be at, I noticed radio antennas coming from a defilade position (pretty hard to see with night vision goggles on). Because I insisted on complete blackout, the mortar tracks were not flying the traditional chemlight Christmas tree from every vehicle, and they were literally invisible, even after I finally saw them.

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Sundown at NTC. When it gets dark, with zero percent illumination (i.e. no moonlight), even 8 tracks will be really hard to find in a ten foot deep hole!!

The GPS got me where I needed to be; I just couldn’t find them. Because I refused to tell them I couldn’t find them, it appeared that I had driven right up on them it was a win for my credibility (and GPS technology…). Because they had used the GPS to get to the right area and then used the terrain to appropriately conceal themselves, it was a win for old-school map-reading skills. This lesson was firmly driven home, for me anyway.

Now, as for people that follow a GPS down a boat ramp, or off a cliff, that is just plain stupid, and we all know that.

4

GPS technology can give us precise locations and is one of the elements critical to get steel on target.

XBrad here- I too had an “early adopter/steep learning curve” experience with SLGR. The system gave your location via an alphanumeric display. That is, your coordinates were displayed as numbers. Not a graphic map representation like you might see in your cars modern GPS system. I had never used one before. Now, just having the ability to determine your location with great confidence was pretty nifty. But you could also program the system to navigate from one waypoint to another. It would give bearing and distance to the next waypoint. Simple, right?

 

Well, as Esli mentions above, looking at the map first is ALWAYS a good idea. I had to drop off a fire team for a recon mission. Again, only a few clicks away, but finding your way by night without doing a map recon of the route was a bad, bad idea. But on a simple mission like this… heck, we’ll even let the gunner have the night off, and just take the Bradley out with only me and the driver as the crew.

 

Finding my way home was every bit as challenging. And SLGRs had an antennae that meant the device had to be held outside the turret of the Bradley. And mine had a loose battery case. I had to take off my night vision goggles, hold the SLGR just right, stand way the heck out of the turret, and try to give my driver, Chuck,  directions left and right to head us back to our unit.

 

While I was focused on reading the little numbers, I wasn’t paying much attention to anything else. So I didn’t even notice the giant tree branch the driver headed under. Not until it hit me smack in the face, and dragged me out of the Bradley’s turret, and had me rolling off the back of Bradley’s hull. And my commo helmet got knocked off. And I was badly stunned. And my driver had no idea that I wasn’t just quietly enjoying the night. He kept driving along, and I was in terror that I would fall off and be crushed under the tracks, or at best left stranded in the middle of nowhere.

 

I finally found my CVC helmet rolling around on the back deck with me and screamed a while till Chuck stopped the track. Apart from some cuts and bruises, I survived. But I never again used GPS to navigate. Only to confirm where I really was.
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5 Comments

Filed under 120mm, armor, army, ARMY TRAINING, Personal

5 responses to “GPS

  1. “…One day, we conducted a training lane consisting of a company attack. I followed in the right rear of a company wedge for about 20 Km. …”

    I remember that training lane. When Brigade HQ requested a block of ground for maneuver familiarization, I volunteered to “scout” the area. My cover story – as SIGO I needed to confirm FM coverage of the maneuver box. Real motivation – as SIGO if you can get out of the TOC for even fifteen minutes to escape the near constant whining about radios, batteries, wires, etc., then you make a run for it!

    Somewhere in my files I’ve got the original map overlay I drew for the maneuver box, including suggested training lanes and routes through the various sand berms (which the Kuwaitis didn’t want us to break up). Tying this back into the GPS discussion, I first rode the area in my M1025. I sat up in the hatch and navigated by terrain association. Occasionally I’d log the data from the GPS and record the waymarks. Ever radio check I’d call in my coordinates and ask for a logged readback from the RTO at the TOC.

    I returned to the training area that afternoon after securing the use of the S-3′s Bradley. We rolled through the box and I confirmed the GPS coordinates recorded earlier. At the end of the day, we had mapped out all the passage points through the berms and all the off-limits areas. And we’d noted all the areas where FM radios would drop out. The overlay provided to my operations officer perhaps erred on the side of TOO much detail, but I figured our operational stance dictated such.

    Lesson learned: GPS is a great tool, but it is best utilized as a supplement to the “old way.” From that day on, I always looked to the GPS as a more a conformation (or correction) to my own observations.

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  2. Elsi, were you with 1st Brigade at the NTC rotation in 1993? An incident during that rotation involved the improper use of PLGRs. As I look back at some of my experiences with the brigade, that incident may have prejudiced the opinions of some key leaders with regard to GPS use.

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    • Esli

      I arrived at the brigade literally during Vigilant Warrior. I graduated AOBC in NOV 94 and drove to FSGA while the brigade was flying away.

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  3. Old school is the best school. A number of Yachtsmen listened to the siren song of sat nav. Many got burned and went back to teh old ways. Some got burned and lost their lives, learning a lesson they’ll never have to remember.

    I read a story by a Yachtsman that singlehanded his boat around teh south Pacific who got called to help in a SAR effort. All they found was the EPIRB floating in the water. You can’t buy seamanship over a counter. Nor can you acquire good soldiering skills from US Cavalry (or Brigade Quartermasters, etc.).

    I gave my son a Garman eTrex before he went to Iraq and told him how to use it. Leave it set to WGS 84 unless told otherwise, MGRS, and pay attention to the map and terrain. When you stop plot the position it gives you on the map and look around you to see if it corresponds to the map. Don’t rely on it as your only nav reference, unless you want to get lost, or do something stupid.

    From what I’m hearing, the Navy is not teaching celestial navigation anymore. Very sill and stupid move, if true.

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    • joe

      Esli, be very glad that you missed Vigilant Warrior. I was at the DMMC, and deployed to Saudi with the 3rd Bde. They had the nightmare of pulling equipment off of the APS. The boats were not loaded in any coherent sequence, (other than the broken stuff went on last and got dragged off first), so everybody had to wait to see whose vehicle came off next.

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