# Objective: When GPS signals are not available (high-Earth orbits, Earth-to-Moon transfers) satellite position estimation is a fundamental requirement for autonomous navigation.
# Techniques: Simulation of satellite dynamics accounting for perturbating effects. Nonlinear estimation techniques (EKF, UKF) for satellite localization [1,2].
# Main features: Based only on angular measurements of celestial bodies. Comparison of different nonlinear estimators

Lockheed Martin Corp. Space Systems Co. in Sunnyvale, CA received a $491.2 million cost-plus-award-fee, cost-plus-fixed-fee, firm-fixed-price contract modification. This is a modification of the Advanced Extremely High Frequency (AEHF) satellite contract to add satellite vehicle #3 (SV3) as envisioned and permitted by a clause in the contract. This action includes the procurement of SV3, and introduces the option for Launch and Operations support.

The impact of artificial satellites on our lives is far-reaching. They have improved telephone and internet services, navigation and broadcasting, weather forecasting, medical assistance, humanitarian aid and much more.

ALOS is one of the world's largest earth observation satellites whose function is to collect global and high resolution land observation data. ALOS data will be made available at conditions similar to those of ERS and Envisat missions, namely for scientific 'Category-1' use as well as commercial applications.

On CNN this morning they ran a segment about Google’s satellite imagery available through Google Earth. I’ve been excited about Google Maps and Google Earth for awhile, so enjoyed watching them show shots of New Orleans before and after Katrina. Google has made updated Katrina related imagery available on their site. One thing CNN said that amazed me was that just a couple years ago they paid over $10,000 for access to satellite imagery Iraq. Now Google is providing a similar service to the general public for free.

Global Navigation Satellite Systems (GNSS), and their regional augmentations, are being developed in a number of countries and users will soon be faced with a confusing array of jargon and capabilities from “competing” systems.

There are currently two GNSS, the Global Positioning System (GPS), which is operated by the United States military and the Global Navigation Satellite System (GLONASS), which is operated by the Russian Federation military. There is also one Chinese Regional Satellite System called Beidou. GPS and GLONASS are currently being modified to make them more useful for civilian applications.

When a satellite pinpoints a distress location within the United States, or its surrounding waters, the information is relayed to SARSAT Mission Control at NOAA’s Satellite Operations Center in Suitland, Md., and then sent to a Rescue Coordination Center, operated either by the U.S. Air Force, for land rescues, or U.S. Coast Guard, for water rescues.

KODAMA (DRTS), a data relay test satellite launched by the H-II A launch vehicle from the Tanegashima Space Center (TNSC), serves as a data relay station.
A data relay test satellite is a kind of communications satellite in a geostationary orbit that relays data among Low Earth Orbit (300-1,000 km altitude) spacecraft (such as satellites) and ground stations. This relay can dramatically extend the area where real-time communication between Low Earth Orbit spacecraft and ground stations are possible.

The KODAMA, launched in September 2002, completed its six-and-half-year regular operation phase, and entered the post operation phase.
The KODAMA successfully performed inter-satellite communication experiments with the Advanced Land Observing Satellite "DAICHI" at a global-leading speed of 278 Mbps, and contributed to DAICHI's earth observation activities by relaying a huge volume of data acquired and transmitted by the DAICHI.

We all have our favorite radio stations that we preset into our car radios, flipping between them as we drive to and from work, on errands and around town. But when you travel too far away from the station, the signal breaks up and fades into static. Most radio signals can only travel about 30 or 40 miles (48 to 64 kilometers) from their source. On long trips, you might have to change radio stations every hour or so as the signals fade in and out. And it's not much fun scanning through static trying to find something -- anything -- to listen to.