Huawei Airbridge BTS3612A-1900 Technical Manual page 57

Technical Manual
Airbridge BTS3612A CDMA Base Station
This kind of GPS receiver is capable of tracking 8 satellites concurrently. It receives
GPS signals of band L1 and tracks C/A codes.
Inside the receiver, the RF signal processor makes frequency down-conversion to the
GPS signals received by the antenna to get the Intermediate Frequency (IF) signals.
The IF signals are then converted to digital signals and sent to 8-path code and carrier
correlator, where signal detection, code correlation, carrier tracking and filtering are
performed.
The processed signal is synchronized and sent to the positioning Micro Processing Unit
(MPU), which controls the operational mode and decoding of the GPS receiver,
processes satellite data, measures pseudo-distance and pseudo-distance increment
so as to figure out the position, speed and time.
The receiver should be powered with regulated 5V DC and the sensitivity of the
receiver is -137dBm.
II. Dual-satellite receiver
The principle of the dual-satellite receiver is similar to the GPS receiver. It has 20
receiving paths and can be upgraded from GPS L1 to GPS/GLONASS L1+L2 or other
solutions.
Chapter 4 Antenna & Feeder Subsystem
4-8
System Principle