Will you be…

Mapping or Navigating?

Which GPS Receiver Do I Need?

“Mapping” is any activity or process thatproduces a graphical representation of a ground feature by means of a point, line or polygon.

While mapping you may need to produce attributedata concerning the features that you are mapping.

One resulting product from a mapping project is a GIS data layer or theme.

If you would like to learn more about attribute featuredata collection choose the “Mapping Features” buttonbelow, otherwise pick the “Continue” button.

ContinueMappingFeatures

Sub-meter 5 – 25 m.

Post-ProcessedDifferential

Autonomous

NDGPS WAAS

Mapping

Real-TimeDifferential

1 – 5 m.

Post-ProcessedDifferential

Home

RequiredAccuracy:

Process:

1 – 5 m. 5 – 25 m.

Autonomous

NDGPS WAAS

Navigation

Home

Real-TimeDifferential

RequiredAccuracy:

Process:

Collect GPS Data

Download andPost-Process the GPS Data

Post-Processed Differential Corrections

• 1 – 5 meter accuracy• Sub-meter if you collect and process carrier-phase data

More InformationBack Back to

Mapping

Autonomous Receiver Operations

5 – 25 meters

MoreInformationBack Back to

MappingBack to

Navigating

Real-time Differential Corrections

1 – 5 meters

1 – 5 meters

NDGPS WAAS

MoreInformationBack Back to

MappingBack to

Navigating

Post-Processed Differential Corrections

Examples of Receivers:

• Trimble XR and XRS Series (~ $10,000)• Trimble GeoExplorer CE XT (~ $6,000)• Garmin Receiver with Rhino™ Data Collection andPost-processing Software (~$1500)

Back Back toMapping

Back toNavigating

Autonomous Receiver Operations

Examples of Receivers:

• Trimble XR and XRS Series (~ $10,000)• Trimble GeoExplorer CE XT (~ $6,000)• CSI MiniMax (~ $2500)• Garmins (~ $100 - $1000)• Magellans (~ $100 - $3000)

Back Back toMapping

Back toNavigating

Real-time Differential Corrections

Examples of Receivers:

• Trimble XR and XRS Series (~ $10,000)• Trimble GeoExplorer CE XT (~ $6,000)• CSI MiniMax (~ $2500) • Garmins (~ $200 - $1500)• Magellans (~ $200 - $3000)

Back Back toMapping

Back toNavigating

Sub-meter Considerations:

• Expensive• 10 minute (or more) approximate occupation time• Used primarily for point positioning

Back

1 –5 Meter Accuracy Considerations:

• Post-processed option is more expensive than real-time• Real-time may not be available or practical for operations

Back

Autonomous ( 6 –25 m.) Considerations:

• Can be very inexpensive• Will not meet most requirements for mapping

Back

Nationwide Differential GPS ServiceConsiderations:

• More expensive than WAAS since an additional receiver is required

• Is usually (but not always) slightly more accurate than WAAS

• Is not line-of-sight. It can be used in the trees andin terrain that WAAS cannot

Back MoreInformation

Coast Guard NDGPS Website:http://www.navcen.uscg.gov/dgps/Default.htm

Wide Area Augmentation SystemConsiderations:

• Less expensive than NDGPS because no additionalreceiver is needed. GPS receiver must be WAAS enabled

• No wires• Limited to line of sight operations to geo-stationary

satellite parked over equator• Unreliable in many field operating environments• Usually less accurate than NDGPS

Back MoreInformation

Department of Transportation WAAS Website:http://gps.faa.gov/programs/waas/howitworks.htm

Mapping Features:

There are basically two options for collecting attributesin the field:

• Trimble equipment with TerraSync or ArcPAD• Data collection software such as ESRI’s ArcPAD on a PDA plugged into any GPS receiver.

Each has advantages and disadvantages. Pick the “More Information” button for additional info.

Back toMappingBack More

Information

Trimble Equipment:

• GeoExplorer XT is relatively small and self-contained• Trimble XR and XRS are highly accurate and reliable• Pathfinder Office Software is powerful and feature packed• Expensive ($6000 - $10,000)Note: If you use ArcPAD and want to do post-processed differentialcorrections then you must buy “GPS Correct” software (~$500) from Trimble.

GeoExplorer XT Trimble XR

More Information at Trimble’s website:http://www.trimble.com Back to

MappingBack MoreInformation

PDA with Data Collection Software:

• Flexible solution• Wide range of related costs ($250 - $6000) depends onselected hardware and software• Can be very powerful and feature packed

Back toMappingBack

ERSI’sArcPAD