ATELLITE 2. Signal Processing L,CA可[.D叵2. RECEIVER Carri Message is the recovery of the signal components Goal extraction of the codes for the satellite clock readings and the navigation message General Characters 5.2.1 Receiver Desig 1. The signal emitted from the satellite contains three components in the symbolic form variety of receivers on the market used for different purposes (I C/A, D). (navigation, surveying, time transfer)and with different features. Lp, Y, D), and (L2,Y,D) contains Signal reception Basic concept of 2. The received C/A-code signal on L, is twice as powerful as the Y-code sign 3. The same ratio exists between the Y-code signals on Ll and L Control device Storage device 4. The B T IR satellites may transmit signals with less Microprocess he present constellation, since the nominal power lower than the present signal strength. Power supply 1. Antenna Design: 2. Microprocessor: 1. The microprocessor controls the entire system and 2. The electronic center should be close to its geometric center and should be insensitiy enables real-time navigation by means of code tation and inclination This becomes particularly important in kinematic 2. The control device provides interactive communication with the receiver elevation or multipath signals. At present, best achieved by choke ring antennas. 3. Commands can be keyed in and diagnostic or other satellites above the horizon and, after pre transmits signals to the radio frequency(RF 4. The control device is, therefore, usually designed as ntenna may be designed for only the primary k both LI and L2 carriers. Most of the antennas sold today are microstrip antennas.4 2. Signal Processing is the recovery of the signal components • reconstruction of the carrier wave • extraction of the codes for the satellite clock readings and the navigation message. Carrier Code Message SATELLITE L1, C/A, D L1, Y. D L2, Y. D RECEIVER Carrier Code Message Goal 1. The signal emitted from the satellite contains three components in the symbolic form • (L1, C/A, D), • (L1, Y, D), and • (L2, Y, D). 2. The received C/A-code signal on L1 is twice as powerful as the Y-code signal on L1. 3. The same ratio exists between the Y-code signals on L1 and L2. 4. The Block IIR satellites may transmit signals with less power than the present constellation, since the nominal power is 6 dB lower than the present signal strength. General Characters 5.2.1 Receiver Design A variety of receivers on the market used for different purposes (navigation, surveying, time transfer) and with different features. The receiver unit contains –Signal reception –Signal processing Basic concept of a receiver unit 1. One important design criterion is the sensitivity of the phase center. 2. The electronic center should be close to its geometric center and should be insensitive to rotation and inclination. This becomes particularly important in kinematic applications. 3. Antenna should have a gain pattern which filters low elevation or multipath signals. At present, this is best achieved by choke ring antennas. 1. Antenna Design: An omnidirectional antenna receives the signals of all satellites above the horizon and, after preamplification, transmits signals to the radio frequency (RF) section. The antenna may be designed for only the primary carrier L1 or for both L1 and L2 carriers. Most of the antennas sold today are microstrip antennas. 1. The microprocessor controls the entire system and enables real-time navigation by means of code pseudoranges. 2. The control device provides interactive communication with the receiver. 3. Commands can be keyed in and diagnostic or other messages can be displayed. 4. The control device is, therefore, usually designed as keyboard display unit. 2. Microprocessor: