The Global Positioning System Advanced Tools

Sources of GPS Error Standard Positioning Service (SPS ): Selective Availability:0 to 100 meters Ionosphere:5.0 to 7.0 meters Troposphere:0.5 to 0.7 meters Satellite clocks:< 1 to 3.6 meters Orbital errors:< 1 meter Receiver noise:0.3 to 1.5 meters Multipath:undetermined User error:Up to a kilometer or more Errors are cumulative!

L1 C/A Code This time difference can be calculated and used to correct for Ionospheric and Tropospheric created errors. L2 P(Y) Code Dual Frequency Positioning Signal propagates through atmosphere at different rates due to different frequencies.

DGPS Site Receiver Post-Processed Differential GPS

Trimble’s Pro XR Trimble Geo CE XT and XM Trimble GPS Pocket

DGPS Site DGPS Receiver Receiver Real-Time Differential GPS

NDGPS Nationwide Differential Global Positioning Service Advantages: 1 meter, 95% real-time accuracy when the user is within 100 miles of station Optimized for surface (maritime and terrestrial) applications with medium frequency, “ground hugging” signal and is not line-of-site dependent Fully operational in areas of coverage

NDGPS Nationwide Differential Global Positioning Service Disadvantages: Accuracy degrades at a rate of approximately 1 meter per hundred nautical miles More user equipment needed for most receivers Can be susceptible to RF interference Accuracy and usage are distance dependent System is operational but the coverage not completed yet

GPS / NDGPS Beacon System Trimble’s “BoB” CSI’s MBX3 Beacon Receiver

NDGPS National Differential Global Positioning System

WAAS Wide Area Augmentation System < 7 meters real-time accuracy Accuracy not distance dependent No additional receiver needed Inexpensive Advantages:

WAAS Wide Area Augmentation System Disadvantages: Does not work well in canopy cover Satellite are geo-stationary over equator Not declared operational yet

WAAS / Beacon / Omnistar / GPS Receiver System CSI’s DGPS Max Garmin GPSMap 76 and V Trimble’s Pro XR Trimble Geo CE XT and XM Garmin GPSMap 176

Why Should You Do Differential Corrections? Improved Accuracy ( still have atmospheric degradation of sv signals ) Positional Integrity ( Are you where you say you are? ) Geodetic Tie to NGS Monumentation Network

What’s Coming for GPS System? Better, smaller and less expensive receivers Closer integration into existing equipment, watches, cell phones, data collection devices, etc. Dual Frequency, C/A Code FAA satellite based differential service - Wide Area Augmentation System, WAAS Double coverage of NDGPS for CONUS

Latest GPS Technology Casio GPS Watch Trimble GPS Pocket Trimble Geo CE XT and XM Garmin GPS V CSI DGPS Max and MiniMax Garmin GPSMap 76s

Latest Communication Technology Garmin’s NavTalk GSM Wireless Phone Garmin Rino FRS / GRSM Radio and GPS Reciever

Latest Communication Technology Racal Project 25 Voice / Data Radio CSI GT300 GPS Enabled Digital Cell Telephone

Latest Mapping Technology ERSI’s ArcPAD TerraSync

Handheld Mapping In-the-field data collection and information display. Combine data sets Display valuable data sources Query attribute information

Data Collection Softwares Trimble TerraSync ESRI ArcPad Fieldworker TDS Solo CE Various PalmPilot Softwares

Minimum Suggested Handheld Requirements (August ‘03) Min. 206 Strong Arm chipset 32 Mbs of RAM PC Card (or compact flash) expansion capability Daylight viewable screen! Ruggedized (if possible)

Panasonic Toughbook 01 Examples: Panasonic Toughbook 01 (32 Mbs of RAM) Serial AutoSync cable 1 gig IBM Microdrive and / or 512 mb Secure Data card Extra removable battery with charger Approximate cost: $

Latest GPS Imaging Technology 3D Marketing’s Photo Link and GPS Tag Software Trimble’s Media Mapper

Digital Camera/GPS Imaging Systems Latitude and Longitude Datum Elevation FMSS Facilities information Archeological descriptions Viewing direction I&M database unique identifiers Basically, anything that you want to watermark on photo.

Digital Camera/GPS Imaging Systems