🛰️ How GPS Works
All GPS devices—whether car sat navs, handheld units, or smartphones—rely on signals from orbiting satellites to determine your location.
💡 Professional-grade GPS units (like those used by surveyors) can also access ground-based radio signals for enhanced precision. This is called Differential GPS (DGPS), but it’s not available on consumer-level devices used by geocachers.
🌐 GPS Satellite Systems
There are three major satellite navigation systems currently in operation:
- GPS (USA): Managed by the U.S. military and used worldwide. Popular brands like Garmin and Magellan rely on this system.
- GLONASS (Russia): Offers similar signal capabilities but with different satellite coverage. Many newer Garmin handhelds support GLONASS.
- Galileo (Europe): Operated by the European Space Agency. It’s still being rolled out but will be compatible with existing GPS devices.
📡 Satellite Coverage and Accuracy
The U.S. GPS network consists of over 30 satellites orbiting Earth at an altitude of 20,200 km (12,600 miles). Each satellite takes about six hours to travel from horizon to horizon.
Most GPS receivers have 12 channels, allowing them to connect with up to 12 satellites simultaneously. To calculate your position accurately, your device needs signals from at least four satellites. The more satellites it connects to, the better the accuracy.
📍 For more details, see the section on “Features of a GPS.”
🔄 Combining GPS and GLONASS
While GLONASS has fewer satellites than the U.S. GPS network, it provides comparable accuracy. Devices that access both systems won’t necessarily be more accurate, but they will acquire a position fix more quickly by connecting to a broader pool of satellites.
The Basics – different types of GPS available
There are 4 broad types of GPS available. With the exception of the car sat nav they all provide basic navigation functions allowing you to enter and save waypoints (caches for example), navigate to waypoints and create and navigate routes. They all have a compass allowing you to see which direction to go. The radio receiver that picks up the satellite signal varies between models so some are more sensitive than others which means they pick up the satellite signal faster and work better in poor signal areas (under trees for example). The number of waypoints and routes available and how the compass works differs between the types as does the amount of internal and external memory in which you store waypoints and maps. Please note the GPS devices shown are just examples and not a complete list. For that please refer to the comparison table at the bottom of this page.
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🧭 Basic Handheld GPS
Basic handheld GPS units offer essential navigation features and a built-in compass. However, they do not support maps and have limited capacity for storing waypoints and routes.
- Connection to a PC is possible, though some models (like the eTrex H) require a special serial cable.
- Most models are not “paperless,” meaning they cannot download full cache details—only the GC code and coordinates.
- The Garmin eTrex 10 is an exception, offering limited paperless functionality.
Examples:
- Garmin eTrex and eTrex H
- Garmin GPS60
- Garmin eTrex 10
🗺️ Mapping & Paperless Handheld GPS
These advanced models include all the navigation features of basic units, plus support for detailed maps. You can view your location, routes, and waypoints directly on the screen.
- Cache information (description, hints, logs, waypoints) can be downloaded—no need to print cache pages.
- Most models feature increased memory (often via microSD cards), allowing for more maps and waypoints.
- Common features include electronic compasses, altimeters, and touchscreen interfaces for easier data entry.
- PC connection is simple via USB, enabling fast cache transfers from geocaching websites.
💡 Note: Paperless features are available only to Premium Members.
Examples:
- Garmin eTrex 20x, 30x series
- Garmin GPSmap60, GPSMap 62x
- Garmin Montana 6xx, Oregon 5xx/6xx
- Garmin Monterra
- Magellan GC, eXplorist 710, 610, 510, 310
📱 Smartphones
Many smartphones come with built-in GPS receivers and can run geocaching apps. They function similarly to handheld GPS units but have some limitations:
- Shorter battery life
- Less rugged for outdoor use
- May require additional apps for map storage and caching features
Examples:
- iPhone (iOS)
- HTC (Android)
📲 Specific geocaching apps for smartphones are discussed later in the guide.
🚗 Car Sat Nav
Car navigation systems are designed for driving and can be used for geocaching, but they’re not ideal:
- They often lack compass arrows and waypoint countdowns found in handheld devices.
- Battery life is limited for outdoor use.
- Navigation may be less precise when off-road or away from mapped roads.
Examples:
- TomTom
- Garmin Nuvi
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🧭 Features of a Handheld GPS for Geocaching
Handheld GPS units come with a variety of features that enhance your geocaching experience. Here’s a breakdown of the most important ones:
📡 Receiver
The GPS unit includes a radio receiver that picks up signals from satellites. These receivers are manufactured by various companies, and GPS brands choose the ones that best suit their models.
- Most modern GPS units feature high-sensitivity receivers, which can detect weaker signals—especially useful under tree cover or in urban areas.
- The satellite screen displays the number of satellites connected and your approximate location accuracy.
- Example: Garmin Oregon 550
🧭 Compass
All handheld GPS units include a compass, but the type varies:
- Basic GPS Compass: Uses satellite signals and requires movement to function. If you stop or turn while standing still, the needle may freeze.
- 2-Axis Electronic Compass: Works like a traditional compass and functions while stationary. Must be held horizontally.
- 3-Axis Electronic Compass: Offers accurate readings regardless of how the device is held. Recommended for best performance.
🔍 Tip: Set your compass to “bearing” mode for an arrow that points directly to your waypoint.
📍 Waypoints
Waypoints are specific coordinates that your GPS can navigate to. Geocaches use waypoints to mark locations.
- You can enter waypoints manually or transfer them from your PC using cache pages or Pocket Queries*.
- Once selected, the GPS will guide you with a compass arrow and a distance countdown.
- Non-paperless GPS units store all locations as waypoints. Paperless models can store both waypoints and full geocache data.
Ease of Data Entry:
- Basic models (e.g., Garmin eTrex H, Geko): Manual entry is time-consuming.
- Mid-range models (e.g., Garmin eTrex, GPSmap60, Magellan GC): Easier on-screen input.
- Advanced models (e.g., Garmin Oregon/Montana, Magellan eXplorist 510/610/710): Touchscreen for quick data entry.
*Pocket Queries and paperless caching require Premium Membership.
More about paperless caching and transferring caches
⛰️ Altimeter
Some GPS units include an altimeter to measure elevation:
- Basic Altimeter: Uses satellite data.
- Barometric Altimeter: Uses air pressure and requires calibration. More accurate but not essential for geocaching.
🔌 Connecting to a PC
To transfer cache data from your PC to your GPS:
- Basic models (e.g., Garmin eTrex H, Geko): Use a serial cable (often sold separately).
- Other models (Garmin, Magellan): Use a standard USB connection.
Premium members with paperless GPS units can transfer up to 1,000 caches at once using Pocket Queries.
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🧭 Features of a Handheld GPS for Geocaching
Handheld GPS units come with a variety of features that enhance your geocaching experience. Here’s a breakdown of the most important ones:
📡 Receiver
The GPS unit includes a radio receiver that picks up signals from satellites.
- Modern units use high-sensitivity receivers that detect weaker signals (e.g., under trees or in urban areas).
- Look for “high sensitivity” in the specifications for better performance.
- The satellite screen shows the number of satellites and your approximate accuracy.
🖼️ Example: Garmin Oregon 550
🧭 Compass
All handheld GPS units include a compass, but the type varies:
| Compass Type | Description | Movement Required | Orientation Sensitive |
|---|---|---|---|
| GPS Compass | Uses satellite signal; freezes when stationary | Yes | No |
| 2-Axis Electronic | Works like a traditional compass; must be held flat | No | Yes |
| 3-Axis Electronic | Most accurate; works in any orientation | No | No |
🔍 Tip: Set your compass to “bearing” mode for an arrow that points directly to your waypoint.
📍 Waypoints
Waypoints are specific coordinates that your GPS can navigate to.
- Used to mark geocache locations (e.g., traditional, multi, or mystery caches).
- Can be entered manually or transferred from your PC using cache pages or Pocket Queries*.
- Once selected, the GPS guides you with a compass arrow and distance countdown.
Data Entry by Device Type:
| GPS Type | Data Entry Method | Notes |
|---|---|---|
| Basic (e.g., eTrex H, Geko) | Manual entry via button navigation | Time-consuming |
| Mid-range (e.g., eTrex 20x, GPSmap60) | On-screen number/letter selection | Easier to use |
| Advanced (e.g., Oregon, Montana) | Touchscreen input | Fast and user-friendly |
*Pocket Queries and paperless caching require Premium Membership.
📱 Features of a Smartphone for Geocaching
Smartphones like iPhones and Android devices offer powerful tools for geocaching through dedicated apps. These apps allow you to:
- Search for nearby caches
- Download cache details
- Log your finds directly online
You can find these apps in the Apple App Store or Google Play Store.
📡 GPS Sensitivity & Navigation
Modern smartphones have highly sensitive GPS receivers that are generally suitable for geocaching. However, there are a few limitations compared to dedicated handheld GPS units:
- Adding and navigating to waypoints may be less intuitive.
- Smartphones are multi-purpose devices—GPS and compass are just part of a larger suite of features.
- Handheld GPS units are purpose-built for navigation, offering more focused functionality.
🧭 Accuracy When Placing Caches
While smartphones are great for finding caches, placing them requires precise coordinate recording.
- Smartphones use both GPS and mobile radio signals (triangulation) to determine location.
- Poor GPS signal may result in inaccurate coordinates, and you may not be aware of the error.
- Accuracy depends on the phone’s GPS chipset.
📌 Tip: When using a smartphone to record coordinates:
- Leave the phone in an open area with a clear view of the sky for at least 5 minutes.
- Walk to the cache site from multiple directions (30–50 feet or 10–15 meters away).
- Average the readings to improve accuracy.
🔗 Help Center article on using apps to find and record coordinates
