# Presentation: 737526

## Improving the GPS L1 Signal

**GPS III Offers the Opportunity**

**Larry Hothem**
**CGSIC**
**10 March 2004**

## Introducing L1C Project Leadership

**Introducing L1C Project Leadership**

**2Lt. Jason Taylor**

**Tom Stansell**

**1Lt. Bryan Titus****Co-Lead, JPO**

**Dr. Ken Hudnut****Co-Lead, USGS**

## An Invitation:   Contact Information

**E-mail:****	****L1C_GPS@USGS.gov**
**FAX:****	****626-583-7827**
**Mail:****	****L1C GPS **
**	****	****Attn: Ken Hudnut**
**	****	****525 South Wilson Ave. **
**	****	****Pasadena, CA  91106-3212**

## Historic Changes and New Initiative

**Historic Changes and New Initiative**

**GPS has had only 3 navigation signals**
**L1 C/A, L1 P/Y, L2 P/Y**
**GPS modernization will add at least 4 new signals**
**L1 M, L2 M, L2C, and L5**
**Opportunity for input to signal preferences limited**
**L5 design:   mostly input by an RTCA committee**
_**Historic initiative**_**:**
**The IGEB has funded the L1C Project to seek “broad” national & international input on best approach for a new L1 civil signal**

## First L1C Modernization Question

## Constrained to Fit Between M & C/A

**P(Y) is the “old” military signal**
**So, fitting between C/A and M codes is the focus**
***Note change in frequency scale***

## Such As BOC(1,1)  (OK for M and for C/A)

**BOC(1,1) Spectral Separation Coefficient (SSC)**
**For C/A = ****-67.8 dB/Hz**
**For M =****-82.4 dB/Hz**

## News:  Galileo Signal Decision http://europa.eu.int/rapid/start/cgi/guestfr.ksh?p_action.gettxt=gt&doc=IP/04/264|0|RAPID&lg=EN&display=

**Loyola de Palacio welcomes the outcome of EU/US discussions on GALILEO **
*The United States and the European Commission, joined by the European Union Member States, held a successful round of negotiations in Brussels on 24-25 February 2004. The delegations built upon progress made in The Hague and in Washington and were able to reach agreement on most of the overall principles of GPS/Galileo cooperation. *
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- Adoption of a common baseline signal structure for their respective open services (the future GPS intends to use a BOC 1,1 signal whereas the Galileo open service intends to use a fully compatible optimized version of the same signal which guarantees an high-level of performance).

## GPS III Power Control Thinking

**GPS III Power Control Thinking**

**Total C/A + L1C ****(-151.2 dBW Max)**

**L1C (-153 dBW Max)**

**Future C/A****(-158.5 dBW Min at 5 degrees El.)**

**Current C/A Measurements**

## First L1C Modernization Question

## Next L1C Modernization Questions

**Next L1C Modernization Questions**

**?**

## Choose One After Each Diamond

**Choose One After Each Diamond**

**What is best for your applications?**

**(?)**

## Questionnaire Page 1

## Questionnaire Page 2

## Schedule a Web-Based Interview

**E-mail:****	****L1C_GPS@USGS.gov**
**FAX:****	****626-583-7827**
**Mail:****	****L1C GPS **
**	****	****Attn: Ken Hudnut**
**	****	****525 South Wilson Ave. **
**	****	****Pasadena, CA  91106-3212**
**See Tom Stansell here or write**
**Tom@Stansell.com**