GPS(Global Positioning System)
PMB 2520 Hammerhead
The PMB 2520 Hammerhead is a IC sulution for GPS that producted by the Infineon Technologies. It allows the usage of assistance data by surpporting A-GPS standards.
Modules of the Hammerhead
The Hammerhead consists of the following modules:
- RF front-end with on-chip, high gain and low noise, LNA, I/Q mixers, on-chip polyphase complex IF filter, digitally controlled AGC, and 3-bits ADC for the I and Q paths.
- Sigma-Delta RF PLL with on-chip PCO and on-chip loop filter.
- Embedded PLL and NCO for baseband clock generation.
- Multiple channels digital mixers and parallel correlator engines to enable real time correlation of the PRN code for up to 14 satellites.
- Post processor including peak detection logic
- SRAM for storing correlation results
The Hammerhead integrates 3 serial interfaces:
The UART in the Hammerhead is a full-duplex UART interface. It is fixed in 8N1(8 data bits, no parity, 1 stop bit) mode. On the GTA01, the host processor connect with the Hammerhead through the UART.
Host software Architecture
The Hammerhead driver software is delivered as a library. The library has two seperate interfaces for the software. One part of them provides an interface to communicate with the high level software. The other part is the HAL(Hardware Abstraction Layer), it is used to communicate with the system.
The library provides the following infomations to the high level software:
- Position data
- Library status
The high level software sends the following messages to the library:
- Assistance data
- Positioning Commands
- Configuration Commands
- Time-out and Packet Available
The library communicates with the system at the following part:
- Communications Drivers
- System Timer
- NV storage
- Log buffer