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Wireless GPS and Ethernet GPS Time Receivers
The GPS satellites obtain their time from the U.S. Atomic time standard, providing legally traceable time to the wireless clock system. Two GPS models are available. The RC161 receives GPS time and sends it wirelessly to all master clocks within radio range. The
MCR100GPS receives GPS time and sends it over the computer network to any number of master clocks.
The RC161 wireless GPS receiver assembly consists of two modules: GPS receiver and wireless transceiver. The GPS receiver mounts in a location that has a view of the sky, while the wireless transceiver is normally located indoors. The GPS receiver acquires time data from the GPS satellites and sends it to the indoor wireless transceiver over a cable. The wireless transceiver converts the time data to secure time packets and broadcasts the data to the wireless network once per minute. The wireless transceiver must be located with 150 feet of at least one RC100 master clock (330 feet in open space construction). Repeaters may be used to extend this range.
As soon as the GPS receiver obtains a time lock, the transceiver will begin broadcasting time to the master clocks.
The MCR100GPS consists of two modules, the GPS receiver and Ethernet NTP time server.
The receiver acquires time data from the GPS satellites and sends it to the Ethernet NTP time server. The time server decodes the raw GPS time broadcasts and sends the data to one ore more master clocks over the computer network. A status LED will blink when the interface receives valid time packets from the GPS receiver.
The RC100 master clock includes an indicator on the right side of the display to indicate when the clock has received time updates from either a wireless GPS receiver (G*) or an NTP/GPS network time update(E*). Once the clock locks onto the time signal, the sync indicator will remain on. If sync reception is lost for more than two hours, the sync indicator will turn off.
There are normally several satellites overhead at any point in time. The GPS antenna may be mounted indoors on a windowsill. This mounting method allows a partial view of the sky, which is enough to receive 2 to 3 satellites. The antenna may also be placed below a skylight. The
30
GPS antenna is water tight and may be mounted outdoors, on a roof or exterior wall. The following diagrams illustrate antenna positioning:
View of Sky
Inside Satellite
Satellite
Satellite
Satellite
View of Sky
Inside
GPS antenna
Window
Specifications
General
GPS antenna
To clock
Antenna cable Outside
Antenna cable
Outside
To clock
GPS Receiver Specifications
Parameter Description
L1 frequency, C/A code (SPS)
32 independent tracking channels
Reacquisition
Operating Temperature
Storage Temperature
Operating Humidity
Water Resistance
Primary Power
Power Consumption
Protocol
Signal Level
NMEA Message
DGPS Capability
EMI filter
SBAS
Power Cable
Enclosure
Connector
Mounting Base
Weight
This specification is subject to change without notice
Warm start
Hot start
Velocity
Vibration
Default
35 seconds (typical)
1 second (typical)
100 ms (typical)
500 m/sec.
4G max.
-30C to +80C
-40C to +85C
0% to 95% RH, non-condensing
100% waterproof
8V to 35V DC
34mA to 44mA @ 12 V DC
NMEA-0183 v3.01 4800 baud
RS232 to the cable adapter, then RS422
RMC, GGA, GSV*5, VTG, GSA*5
RTCM protocol
Rejects power line interference
1 channel (supports WAAS, EGNOS, MSAS)
UL2464/ 24AWG, 45 feet (15M) to the cable adapter, then CAT-5E
High impact, corrosion-proof polycarbonate resin
7 pin circular, hermetically sealed. Gold plated contacts.
110mm(W) x 70mm (L) x 75.2mm (H)
150 grams (without cable)
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