By JOHN FLINN

updated 3:18 p.m. ET May 8, 2006

YOSEMITE NATIONAL PARK, Calif. - I am a human cruise missile, zigging and zagging through the forest with the same technology that guides our military's smart bombs to their bridges and bunkers.

If all goes to plan, data beamed from a cluster of navigational satellites 22,240 miles overhead will steer me unerringly to my target: a bucket with some tchotchkes in it.

This relatively new pastime, basically a high-tech scavenger hunt, is called geocaching, and it's become wildly popular among owners of handheld GPS (Global Positioning System) units.

It's so popular, in fact, that the Tenaya Lodge, just outside Yosemite National Park near Wawona, began offering a geocaching program along with its nature hikes and horseback riding outings last year. I signed up for it to sample both the sport and the hotel.

Built 15 years ago and renovated recently, the 244-room Tenaya Lodge is the grandest of Yosemite's perimeter "gateway" hotels catering to the park's overflow and visitors who prefer to put a little distance between themselves and Yosemite Valley's bustle.

With a large porch supported by columns of river stones and a grand, three-story high trussed lobby with American Indian-patterned chairs and a large stone hearth, the hotel looks like a cross between the Ahwahnee and a Marriott (the company that built it.) It's now owned and managed by Delaware North Co., as are the hotels inside the park.

What it lacks in proximity to Half Dome and Yosemite Falls - it's a 40-minute drive away - it tries to make up in comfort. The rooms are modern and more spacious than those at the Ahwahnee or Yosemite Lodge, and come with cable TV and high-speed Internet access. The hotel regularly gets four diamonds from the AAA.

Tenaya Lodge began offering the geocaching program last fall, and I was one of the first to sign up. Essentially, the sport is a cross between orienteering and a treasure hunt using high-tech navigation. Someone hides a "cache" - typically a plastic or metal bucket with a lid - with a logbook and some goodies in it and publishes the precise latitude and longitude on the Web. The goal is to dial those coordinates into your handheld GPS unit and have it lead you to the stash.

Since the sport began in 2000, it has grown exponentially. According to Geocaching.com, there are currently 202,735 caches in 218 countries.

"Some people call it a hobby," said Bryan Roth, co-founder of Groundspeak, the Web site's parent company, "and others call it an addiction."

Geocachers are continually adding new wrinkles to the sport. Some transport little objects from cache to cache around the world, a high-tech twist on the famous traveling gnome.

"There was a little Darth Vader action figure that an Air Force pilot picked up from a cache and took with him to Afghanistan," Roth said. "It's been brought back to a pub in England, and to Texas. It's traveled over 17,000 miles."

Tenaya Lodge offers both a hiking and a mountain biking version of its geocaching program. I signed up for the former. At the hotel's activity counter I was handed a small backpack, a box lunch and a Garmin Rino 130 model GPS unit, which was about the size of a small walkie talkie.

When I switched on the unit, it locked onto four satellites in geostationary orbit - meaning they appear to hover over one point on the globe - and spat out our elevation (5,288 feet) and our exact location (37 degrees, 26.402 minutes by 119 degrees, 36.237 minutes.) Depending on how well it linked up with the satellites, it was accurate to anywhere from 25 to 100 feet. With various "waypoints" pre-programmed, the GPS unit directed my wife, Jeri, and me down a series of increasingly rough dirt roads - the last was four-wheel-drive territory _ and beeped to alert me at various junctions. Or at least it was supposed to. The hotel is still working the kinks out of the system.

MORE FROM SUMMER TRAVEL

Summer Travel Section Front

Museum Day showcases culture at no cost Travel’s inconvenient convenience Get your motor running Top 10 national park lodges FirstPerson: Readers share their summer fun Getting through the dog days of summer Summer fun on the slopes Rock out at the world’s coolest music festivals Discover the granddaddy of scenic road trips World's sexiest beaches Summer Travel Section Front   Add Summer Travel headlines to your news reader: