4.2 Master Control station 4.3 Ground control stations 1. The satellite ephemerides and clock Tasks of csoc alculated at the master control and Collects the tracking data from the monitor stations Calculates the satellite orbit and clock parameters using a received via communication links. are each GPS satellite via S-band radio links. These results are then passed to one of the three ground 2. Formerly, uploading to each satellite was ontrol stations for eventual upload to the satellites performed every eight hours; then the rate has Be responsible for the master control station been reduced to once(or twice)per day Location rg AFB, Califomia for BLOCK I navigation satellite to The Consolidated Space Operations Center(CSOC)at support a prediction span so that the positioning Falcon AFB, Colorado Springs, Colorado for BLOCK II accuracy degrades quite gradually Locations of ground station Ascension Island in the South atlantic Ocean Diego Garcia in the Indian Ocean Kwajalein in the North Pacific Ocean Ephermrides Receiver H Modulation Cesium clock Master Station .Data processing tmospheric data Commander Monitoring station Ground Station 5. User Segment Civilian user 5.1 User Categories There are various other non-military uses trictly speaking, the term user Just one example Even during the early days of th A receiver can be connected to four antennas. When the antennas are placed in a fixed array(e.g, comers of a system. It was envisioned that every aircraft, ship, land vehicle, square), the attitude of the array can be determined in groups of infantry would receiver to coordinate their military activities to its position. For example, placing antennas on Gulf war GPs Receiver stern,and port and starboard points of a ship result in the determination of pitch, roll, yaw, and C/A Code Civil Small ReceiverMilitaryTotal 50080040017005 4.2 Master Control Station Tasks of CSOC: – Collects the tracking data from the monitor stations – Calculates the satellite orbit and clock parameters using a Kalman estimator. – These results are then passed to one of the three ground control stations for eventual upload to the satellites. – Be responsible for the master control station. Location: – Formerly, Vandenberg AFB, California for BLOCK I – The Consolidated Space Operations Center (CSOC) at Falcon AFB, Colorado Springs, Colorado for BLOCK II after. 4.3 Ground Control Stations 1. The satellite ephemerides and clock information, calculated at the master control station and received via communication links, are uploaded to each GPS satellite via S-band radio links. 2. Formerly, uploading to each satellite was performed every eight hours; then the rate has been reduced to once (or twice) per day. If a ground station becomes disabled, prestored navigation messages are available in each satellite to support a prediction span so that the positioning accuracy degrades quite gradually. Locations of Ground Station: – Ascension Island in the South Atlantic Ocean – Diego Garcia in the Indian Ocean – Kwajalein in the North Pacific Ocean • Receiver • Cesium clock • Atmospheric data • Ephermrides • Clock bias • Navigation message GPS GPS Monitoring Station Ground Station Master Station • Modulation • Data processing • Commander 5. User Segment 5.1 User Categories Military User Strictly speaking, the term "user segment" is related to the DoD concept of GPS as an adjunct to the national defense program. Even during the early days of the system, it was planned to incorporate a GPS receiver into virtually every major defense system. It was envisioned that every aircraft, ship, land vehicle, and even groups of infantry would have an appropriate GPS receiver to coordinate their military activities. 5000 8000 4000 17,000 Military Total Receiver Small Receiver Receiver C/A Code Civil Receiver Gulf War GPS Receiver Civilian User There are various other non-military uses. Just one example: A receiver can be connected to four antennas. When the antennas are placed in a fixed array (e.g., corners of a square), the attitude of the array can be determined in addition to its position. For example, placing antennas on the bow, stern, and port and starboard points of a ship would result in the determination of pitch, roll, yaw, and position of the vessel