# Presentation: 141452

## High Accuracy DGPS Program

- Jim Radice
- September 11th, 2001

## Program Objectives

- Enable Dynamic Positioning at the Centimeter Level throughout the NDGPS Network
- Coexist with the current NDGPS Broadcast
- Minimize the incremental cost of adding High Accuracy DGPS to NDGPS Sites
- Utilize existing broadcast antenna, reference stations, and site infrastructure
- Incremental Cost ~$75K/ Existing Site

## NATIONWIDE DGPS

*NATIONWIDE DGPS*

** ****Hawk Run**

**  **

** **** ****Macon**

**  ****Grady**

**  **

**   **

**   ****Hackleburg**

**   ****Bobo**

**   **

**  **

** **

** ****Goodland**

** ****Topeka**

** **

** ****Onondaga**

** ****Medford**

** ****Edinburg**

** **

** ****Medora**

** ****Billings**

** **

** ****Great Falls**

** ****Ronan**

** ****Spokane**

** ****Appleton**

** ****Klamath Falls**

** ****Austin**

** **

** **

** **

** ****Bakersfield**

** ****Fenner**

** ****Flagstaff**

** **

** ****Kirtland**

** **

** ****Summerfield**

** **

** ****Pueblo**

** ****Hudson**** Falls**

**  ****GWEN Sites**
**  ****Moved or New Site**
**  ****Coast Guard Site**
**    ****Green - Operating **
**    ****Red - Planned**

** ****Whidbey Is**

** ****Robinson Pt**

** **

**Fort Stevens**

** **

**Cape ****Mendocino**

** **

**Point Blunt**

** **

**Pigeon Point**

** **

**Point Arquello**

** **

**Point Loma**

** **

**Aransas Pass**

**Galveston**

** **

**English Turn**

** **

** **

**Mobile****Point**

**Egmont Key**

** **

**Key West**

** **

** **

** **

**Miami**

**Cape Canaveral**

** **

** **

**Fort Macon**

** **

**Cape Henry**

** **

**Cape Henlopen**

** **

**Sandy Hook**

** **

**Moriches**

** **

**Chatham**

** **

**Portsmouth**

** **

**Brunswick**

** **

**Millers Ferry**

** **

**Vicksburg**

** **

**Memphis**

** **

**Sallisaw**

** **

**Kansas****City**

** **

**St Louis**

** **

**Rock****Island**

** **

**St. Paul**

** **

**Wisconsin****     Point**

**Upper****Keweenaw**

** **

** **

** **

** **

**Whitefish Pt**

**Neebish Island**

**Cheboygan**

** **

**Sturgeon Bay**

** **

**Detroit**

** **

**Saginaw****Bay**

** **

**Milwaukee**

** **

**Youngstown**

**Tucson**

** **

**Arlington**

**  **

**Jackson**

** **

** **

**Duchesne**

** **

**El Paso**

** **

**Gooding**

** **

**Knoxville**

** **

**Cincinnati**

** **

**Monterey**

** **

**Langtry**

**  **

**Rawlins**

** **

**Weiser**

** **

**Henrieville**

** **

**Hagerstown**

**Ashville**

** **

** **

**Martinsville**

**Middlebury**

** **

** **

** ****Jack Creek**

**Odessa**

**    **

**Lexington**

** **

**Omaha**

**Brainerd**

** **

**Hannibal L&D**

** **

** **

**Louisville**

** **

** **

** **

** **

**Acushnet**

**Elmira**

** **

** **

** **

** ****Kensington **

** ****Fayetteville**

**Beaufort**

**Annapolis**

** ****Canton **

**Iowa City**

**St Mary’s**

** **

** **

** **

**Ledyard**

** ****Seneca**

** ****Walnut Grove**

** **

** **

** ****Wenatchee**

**Whitney**

**Clark**

**Chico**

**Penobscot**

**Charleston**

**Savannah**

** **

** **

** **

** **

** **

** **

**Hartsville**

** **

**Reedy Point**

** **

**Driver**

** **

## Participants and Funding

- IGEB Provided $220K in FY01 For Phase 1
- USCG, NGS, FHWA Providing Manpower
- Industry will be invited to participate in various test modes

## High Accuracy DGPS Applications

- More Accurate Land/Marine Surveys
- Snowplowing Highways
- Minimize Vessel Under-Keel Clearance
- Precision Agriculture
- Machine Control (Construction)

## Program Phases

- Phase 1
- Develop Modulator and Data Link Receivers
- Single Site Concept Demonstration
- Broadcast Characterization and Optimization
- Phase 2
- Optimize Broadcast Data Scheme
- Implement Pre-Broadcast Integrity Algorithm
- Multiple Site Concept Demonstration
- Iono/Tropo Modeling
- Application Development

## High Accuracy DGPS Concept

- Broadcast Code and Carrier Phase Data
- All observables (+CRC) contained in 1000 bits in the Compact Format
- Utilize an Advanced Broadcast Link
- Data Synchronized to GPS Time
- Carrier Calibrated with GPS to sub-Hertz levels
- Spectrally Efficient Modulation (GMSK, ß = 0.45)
- “One Second Data” in Compact Mode

## Broadcast Site Configuration

**TRANSMITTER**

**DIPLEXER**

**REFERENCE**
** ****STATION**

**DATA**
** ****FORMATTER**

**MODULATOR**

**TRANSMITTER**

- DGPS/NDGPS

- HIGH ACCURACY
- DGPS

- TO ANTENNA

## Receiver Interface

**GPS RECEIVER**

**DATA LINK**
** ****RECEIVER**

**GPS RECEIVER INTERFACE MODULE (GRIM)**

## Position Determination

- Centimeter Level Float and Integer Solutions
- Sub-Meter Long Range Code Solutions
- Phase 2 Rover Software will be able to incorporate Multiple Broadcast Sites

## Positioning Strategy

- 200 mi

- 200 mi

- Site A

- Site B

- Site C

- Site D

## High Accuracy DGPS Phase 1 Test Plan

- Data Link Characterization & Optimization
- Range, Accuracy, and Convergence Time in Static and Dynamic Scenarios
- Various Formats
- Highly Compact Format
- RTCM SC104 Version 3 (Alpha Version)
- Canned Data Sequences (For Link Characterization)
- Test Distances Will Range Beyond 100 mi

## Industry Participation

- Data Link Receiver, Interface Software, and Test Facilities will be provided
- Selectable Broadcast Observables
- Federal Register Notice
- Information Updates will be posted on the NAVCEN Web Page

## Phase 1 Milestones

- April 01 - Modulator Completed
- October 01 - Data Link Receiver Expected
- November 01 - Broadcast Commences
- Extended (~1 year) Test Period