Altitude struggles, GPS errors nearing the Summit

10/14/2010 6:48 PM EDT

This was when the altitude finally started to affect a number of our group. One of the other guys felt nauseous for most of the day, and both my wife Sarah and Jenna (another of our companions) had very bad headaches. As for me, I kept with the slow walking and tried to maintain hydration, all of which helped prevent me from feeling any ill effects. (You can develop an unhealthy fascination with bushes and large rocks drinking this amount of water!) All the time, I was waiting for some signs of altitude sickness to creep in, having spoken with Chris on his return. He felt worst at the Lava Tower, so surely it was only a matter of time?

Walking slowly to prevent altitude sickness

The Lava Tower, the Western Breach and the Barranco Wall

As you pass the Lava Tower, above you is the massive Western Breach; a huge, 100,000 year old landslide that provides a tough scramble up to the summit. This route had been closed for a few years due to the risk of rock fall, although it is open now.

We can now clearly see the glaciers on the summit, and the scale of the mountain is becoming clear. You tend to think of mountains as tall pointy things, but the summit plateau of Kilimanjaro is 2-3km across. This fact reinforces its scale, when seen from below.

The Summit glaciers come into view

The hike down from the Lava Tower to the Barranco campsite took several hours and featured amazing views out over the African plains. Toward the end of today’s journey, we could see tomorrows target—the Barranco Wall, a 300m scramble up a cliff face. In reality, it is not supposed to be too bad if you like getting your hands on rock. But then, this scramble is located at 4000m and two days from rescue up a mountain; probably best not to fall.

Barranco Wall

Data logger results for the first 3 days

Shown in the below graph is the temperature and GPS-altitude data from my device, for the first few days of walking. You can see the pronounced daily temperature range and also the altitude increments as we trekked up the mountain. It can be seen that, during the first day or two of the trip, we didn’t have any valid GPS data. I believe that this was due to the Ephemeris data being out of date. A GPS satellite transmits this data every 30 seconds to 1 minute (I believe). However, when we turned on the receiver, it was only for 45 seconds. Since the batteries were inserted in the UK (in the Northern Hemisphere), I believe it took quite a few attempts before the GPS receiver was able to correctly calculate that it was now in the Southern Hemisphere and that it should concentrate on a different set of satellites.

Days 1-3 Temperature and Altitude Data

This post is part of a series chronicling the adventures of engineers Darren Wenn of Microchip Technology and Chris McAneny of Future Electronics as they prepare for and climb Africa’s famous Mt. Kilimanjaro, equipped with a special device they designed for taking measurements in extreme conditions.