RXM-GPS-R4-T Linx Technologies, RXM-GPS-R4-T Datasheet - Page 10

• Manufacturer Part Number: RXM-GPS-R4-T
• Description: GPS Modules R4 Series GPS Recvr Module Tape and Reel
• Manufacturer: Linx Technologies

Specifications of RXM-GPS-R4-T

• Rohs: yes
• Frequency Band: 1575.42 MHz
• Number Of Channels: 48
• Time To First Fix (cold Start): 32 s
• Acquisition Sensitivity: - 160 dBm
• Horizontal Position Accuracy: 2.5 m
• Operating Supply Voltage: 3.3 V
• Operating Supply Current: 56 mA
• Interface Type: Serial
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Dimensions: 15 mm x 13 mm x 2.2 mm
• Minimum Operating Temperature: - 40 C

Time To First Fix (TTFF)
TTFF is often broken down into three parts:
Cold: A cold start is when the receiver has no accurate knowledge of its
position or time. This happens when the receiver’s internal Real Time Clock
(RTC) has not been running or it has no valid ephemeris or almanac data.
In a cold start, the receiver takes 35 to 40 seconds to acquire its position.
Warm or Normal: A typical warm start is when the receiver has valid
almanac and time data and has not significantly moved since its last valid
position calculation. This happens when the receiver has been shut down
for more than 2 hours, but still has its last position, time, and almanac
saved in memory, and its RTC has been running. The receiver can predict
the location of the current visible satellites and its location; however, it
needs to wait for an ephemeris broadcast (every 30 seconds) before it can
accurately calculate its position.
Hot or Standby: A hot start is when the receiver has valid ephemeris, time,
and almanac data. This happens when the receiver has been shut down
for less than 2 hours and has the necessary data stored in memory with
the RTC running. In a hot start, the receiver takes 1 second to acquire its
position. The time to calculate a fix in this state is sometimes referred to as
Time to Subsequent Fix or TTSF.
Module Description
The R4 Series GPS Receiver module is based on the SiRFstarIV chipset,
which consumes less power than competitive products while providing
exceptional performance even in dense foliage and urban canyons. No
external RF components are needed other than an antenna. The simple
serial interface and industry standard NMEA protocol make integration of
the R4 Series receiver into an end product extremely straightforward.
The module’s high-performance RF architecture allows it to receive GPS
signals that are as low as –160dBm. The R4 Series can track up to 48
satellites at the same time. Once locked onto the visible satellites, the
receiver calculates the range to the satellites and determines its position
and the precise time. It then outputs the data through a standard serial port
using several standard NMEA protocol formats.
The GPS core handles all of the necessary initialization, tracking, and
calculations autonomously, so no programming is required. The RF section
is optimized for low level signals, and requires no production tuning.
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