W2SG0084i-T Wi2Wi, W2SG0084i-T Datasheet - Page 11

• Manufacturer Part Number: W2SG0084i-T
• Description: GPS Modules GPS SiRFstar IV Module SMD
• Manufacturer: Wi2Wi

Specifications of W2SG0084i-T

• Rohs: yes
• Frequency Band: 1.575 GHz
• Number Of Channels: 48
• Time To First Fix (cold Start): 45 s
• Acquisition Sensitivity: - 148 dBm
• Horizontal Position Accuracy: 5 m
• Operating Supply Voltage: 1.8 V, 3.3 V
• Operating Supply Current: 50 ma
• Interface Type: UART
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Dimensions: 11.2 mm x 12 mm x 2.5 mm
• Minimum Operating Temperature: - 40 C

Wi2Wi, Inc. Doc No. ALT-PDT-DOC Rev.1.61
Datasheet, GPS Module– W2SG0084i
Dated: November 11, 2011
DGPS requires at least two antennas, one for the NavStar L1 CA signal from the satellite and
one antenna for the secondary fix from the VHF/UHF/FM transmitter. Also a secondary
application processor is used to perform “Mixing” calculations between the two fixes. This
increases the size and the expense of the system.
4.2
Wide Area DGPS or WAAS
Wide Area DGPS or WAAS (Wide Area Augmentation System) uses the same concept but
eliminates the need for the secondary RF signal. It accomplishes this by reusing the already
orbiting satellites to re-broadcast other secondary fixes that have been established by ground
based master stations in North America and Hawaii, to measure small variations in the GPS
satellites' signals in the western Hemisphere. Measurements from the reference stations are
routed to master stations, which queue the received Deviation Correction (DC) and send the
correction messages to geostationary WAAS satellites in a timely manner (every 5 seconds or
better). These master stations rebroadcast the secondary fix to the NavStar satellites which
broadcast the secondary fix on unused channel space. This enables a GPS receiver to utilize
the same antenna to reprocess both fixes internal to it also eliminating the need for a
secondary application processor. WAAS enables a GPS receiver to provide positional
accuracy to 300 cm ~ 200 cm. Of course a GPS receiver utilizing WAAS will need an
expanded offering of GPS receiver channels to effective use this feature like the W2SG0084i
which has 48 channels available for this function.
Copyright © 2011 Wi2Wi, Inc.
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