Installation Instructions
Table Of Contents
- Contents
- List of Table
- List of Figures
- 1 About this document
- 2 Product Overview
- 3 Mechanical Dimensions
- 4 Interface description
- 4.1 Pin Definition
- 4.2 Operating conditions
- 4.3 Digital logic characteristics
- 4.4 Power interface
- 4.5 USIM card interface
- 4.6 PCM interface
- 4.7 USB2.0 interface
- 4.8 UART interface
- 4.9 SPI interface
- 4.10 I2C interface
- 4.11 Network light
- 4.12 System Status Indication
- 4.13 Flight Mode
- 4.14 Forced USB download interface
- 4.15 SD card interface
- 4.16 SDIO_WIFI/EMMC interface
- 4.17 PCIe interface
- 4.18 RMII/RGMII interface
- 4.19 AUDIO interface
- 4.20 ADC
- 4.21 GPIOs
- 4.22 Power on/off and reset interface
- 4.23 Antenna interface
- 5 Product characteristics
- 6 Design Guideline
- 7 Storage, Production and Package
- 8 Safety Information
- 空白页面
- 空白页面
L508 Hardware Design
Copyright© Shanghai Mobiletek Communication Ltd 79
Figure 45 GNSS antenna matching circuit schematic
In the image above, elements R1, L1, and L2 are used for antenna matching, and the value of the
elements depends on the antenna being debugged.
In figure 43, the user can add an external LNA for better gain.
The L508LA/L508C/L508TLC integrated GNSS (GPS/BEIDOU/GLONASS) satellite and network
information provides a high availability solution that provides industry-leading performance and
accuracy.
Key indicators for GNSS ARE AS FOLLOWS:
Tracking sensitivity: -160 dBm
Capture sensitivity : -155dBm
Cold start sensitivity: -147 dBm
CN value: C/N0 = S - (-130dBm: 41dB) S= Input Signal Intensity
Accuracy (open space): 2.5m (CEP50)
First Positioning (open space): Hot Start <1s Cold start 35s
Receiving type: 64-channel, C/A Code
GPS, L1 frequency: (1575.42±1.023MHz),
Beidou frequency: 1559.05 ～1563.14 MHz
GLONASS: 1597.5~1605.8 MHz
Default update rate: 1 Hz
GNSS DATA format: NMEA-0183
4.23.3 Antenna Layout guideline
In layout design, the antenna RF transmission line must have a characteristic impedance of 50 ohms,
which is determined by the substrate, the width of the line and the distance from the ground plane.
Figure below shows the reference clearance area for the antenna feed point in the layout.