# Presentation: 822508

## GPS Modernization

- 14 March 2005
- CGSIC IISC Europe

## Civil SatNav Applications

**Enabling**** technology**
**Unlimited growth potential**
**$68 billion industry worldwide by year 2010**
**Wide use**** in transportation safety**
**Aviation, maritime, railroad, highway, etc.**
**Potential to reduce land-based navigation systems**
**Centerpiece of future transportation infrastructure**
**Ever increasing range**** of civil uses**
**Telecommunications, surveying, law enforcement, emergency response, agriculture, mining, etc.**
**Used in conjunction with remote sensing**
**Supporting civil applications never envisioned**

**Notes:**
GPS technology has been and integral part of the infrastructure that we rely on today.   It has enabled growth in applications into areas unforeseen.  It is used widely in reliance

##  GPS Modernization Plan

**Block IIA/IIR**

**Block III**

**Block IIR-M, IIF**

_**III**_**: IIF capabilities &**
**Improved civil signal (L1C)**
**Increased accuracy (4.8-1.2m)**
**Evaluating integrity improvements**** **
**Navigation surety**
**Increased A/J power (+20 dB)**

_**IIA / IIR**_**: Basic GPS**
**C/A civil signal (L1C/A)**
**Std Service, 16-24m SEP**
**Precise Service, 16m SEP**
**L1 & L2 P(Y) nav**

_**IIR-M**_**:  IIA/IIR capabilities &**
**2nd civil signal (L2C)**
**New military code**
**Flex A/J power (+7dB)**** **
_**IIF**_**:  IIR-M capability plus**
**3rd civil signal (L5)**

-  **GPS Modernization Plan**

## Civil Benefits of GPS Modernization

- New signals provide
- Reduced vulnerability to interference
- Calculation of ionospheric corrections at user site
- Improvements in service performance in accuracy, availability, integrity, and reliability
- Provide centimeter-level accuracy for scientific and survey applications
- New spectrally separated signals
- Preserve civil use outside areas of military ops
- New commercial opportunities
- Opportunity to converge services with other global satellite navigation systems

**Notes:**
Civil agencies have contributed to the development of the GPS modernization as members of the GPS High Performance Team and its validation through the Interagency Forum for Operational Requirements (IROC), the DOT Positioning/Navigation Executive Committee (Pos/Nav ExCom), and the GPS Interagency Requirements Oversight Council.

## Benefits of L2C 
Improves service for ~ 50,000 current scientific/ commercial dual-frequency users
Extends service for safety-of-life, single-frequency E-911 applications
Provides 24 dB better protection than C/A against code cross correlation and continuous wave (CW) interference
Signal defined in ICD-GPS-200C

- Improves service for ~ 50,000 current scientific/ commercial dual-frequency users
- Extends service for safety-of-life, single-frequency E-911 applications
- Provides 24 dB better protection than C/A against code cross correlation and continuous wave (CW) interference
- Signal defined in ICD-GPS-200C

**Begins with IIR-M sats**
**First launch:  May 2005**
**24 Satellites:  2012**

**Second Civil Signal (L2C)**

**Notes:**
L2C signals will provide improved service for 50K dual frequency users who are using dual frequency to monitor earthquakes, volcanoes, plate tectonics, for construction surveys, agriculture applications, and oil & mineral exploration.
L2C shares L2 with L2 P(Y) and L2M – specified in ICD-GPS-200 “Navstar GPS Space Segment/Navigation User Interfaces” 
has no nav data on one of its two codes
C/A has 21 dB cross correlation performance – L2C has 45 dB cross correlation performance (24 dB better – 251x)
L2C has a single bi-phase component in phase quadrature with P(Y) code 
time multiplexed at 1.023 MHz chips from 2 L2C codes: CM (moderate, 10,230 chips, 20 ms) and CL (long, 767,250 chips, 1.5 s)
Track “data-less” CL code w/phase-locked loop provides better tracking (L2C CNAV message has lower demod threshold and message structure is more compact)
The first satellite with the L2C capability will be launched in May.

## Third Civil Signal (L5)

- Benefits of L5
- Improves signal structure for enhanced  performance
- Higher power (-154.9 dBW)
- Wider bandwidth (24 MHz)
- Aeronautical Radionavigation Services band
- Co-primary allocation at WRC-2000               (1164-1215MHz)
- Signal defined in IS-GPS-705

-  **L5 code**

**Begins with IIF sats**
**First launch:  2007**
**24 Satellites:  2014**

**Notes:**
The L5 signal is being built into the IIF satellites, and provides a third civil signal.
3 frequencies enable better Ionospheric scintillation corrections.   high-end commercial users will use all three signals, L1C/A, L2C, and L5.

## L1C Signal

- Benefits of L1C
- Adds a modernized L1 civil signal
- In addition to C/A code to ensure backward compatibility
- Higher precision
- Added interference protection
- Enables civil interoperability with Galileo
- Converges with Galileo L1 Open Service

** ****L1C**

**Begins with GPS III sats**
**First launch:  2012**
**24 Satellites:  2017**

**Notes:**
L1C will be available GPS III. 

It will have twice the minimum C/A signal power.
The longer codes will eliminate cross-satellite correlation interference and reduce effect of narrowband interference
The Message improvements include higher resolution, reduced error rate, more flexibility. 
The Data-less signal component pilot carrier improves tracking threshold and is better for high precision phase measurements. 
The increase signal bandwidth (code clock rate) will add interference protection and have less code noise.

## GPS III Status

-  To Lockheed and Boeing for 12-month  	requirements definition effort
-  Leading to Systems Requirements Review
- Selection of final contractor anticipated in 2005
- First launch projected for 2012

**GPS III Status**

## GPS III Civil Benefits

- Significant increase in system accuracy
- Improve robustness to interference
- Improve level of unaugmented integrity
- Improve availability of accuracy with integrity
- Backward compatibility with existing receivers
- Operational capability for L2C and L5
- In combination with GPS IIR-M and IIF satellites
- Flexibility to respond to evolving requirements with limited programmatic impacts
- Opportunity to converge with Galileo Open Service

##  Legacy Improvement

- Legacy Accuracy Improvement Initiative by Air Force and National Geospatial-Intelligence Agency in 2005
- Additional info decreases “Age of Data”, thus increasing accuracy in GPS satellite orbital position and  clock data
- Integrity Failure Modes and Effects Analysis
- Knowledge of GPS failure modes required to design improved integrity monitoring systems
- Continuing improvements to WAAS and NDGPS

**Notes:**
The Objective of the Legacy Accuracy Improvement Initiative is to reduce “User Range Error” .  URE is produced by errors in GPS satellite orbital position and clock data transmitted to users in the GPS nav data message.
Orbital position & clock data is most accurate immediately after uplink to satellite, but becomes less accurate as its “Age of Data” increases.
Using the NGA GPS satellite tracking data provides better knowledge of GPS satellite orbits & clocks, resulting in reduced URE & better navigation accuracy.

The IFMEA objective is to identify GPS integrity anomalies, potential causes and operational impacts of failures and their probability.  
This will improve the reliability of GPS in the future by providing recommendations of GPS SV and OCS design modifications.  Integrity monitoring is provided by civil/military augmentation systems and monitoring networks.

## Current GPS Monitoring Stations

**Notes:**
Currently there are only five GPS monitoring station that feed the Master Control Station.  This configuration allowed for times when a satellite could not be monitored by the Master Control Station.

## GPS Monitoring Stations

***Accuracy Improvement Initiative (AII)***

**Notes:**
The Air Force is in the process of incorporating additional sites from the National Geospatial Intelligence Office as monitor stations.  This will give 2SOPS data from each satellite at a minimum of two monitors.

## JPO GPS Modernization
  http://gps.losangeles.af.mil/engineering/icwg/

Navigation Information Service
  http://www.navcen.uscg.gov
  http://www.navcenter.org/ (mirror site)

E-mail: nisws@navcen.uscg.mil
Phone:  +1 703 313 5900
Fax:      +1 703 313 5920

-   http://gps.losangeles.af.mil/engineering/icwg/
- Navigation Information Service
-   http://www.navcen.uscg.gov
-   http://www.navcenter.org/ (mirror site)
- E-mail: nisws@navcen.uscg.mil
- Phone:  +1 703 313 5900
- Fax:      +1 703 313 5920

- Modernization Information

**Notes:**
The top address is for the modernization information at GPS Joint Program Office.   

The contact information for Navigation Center and our Navigation Information Service website is contained on this slide.  The latest documents on GPS Modernization can also be found on the GPS Modernization page.

## Slide 14