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M3SR Series 4100
If a GPS participant has currently only limited or no GPS satellite visibility, it will automatically
push empty GPS positioning information onto the network. If a participant has never received
the GPS signal (required for scheduled transmissions), it cannot take part in periodic GPS
reporting.
GPS Configuration (Automatic Push Configuration Request)
A controller radio can send a GPS control / configuration command to radio GPS participants
in order to configure the auto push features of addressed participants.
Configure Periodic (Timer Initiated) Transmission of GPS Information
An auto push time interval [in seconds] of the addressed participants can be pre-configured
on-air by sending an Auto Push Configuration Request (APR) from a controller radio.
Selected / addressed provider radios and controller radios with CRP enabled start to period-
ically transmit their current GPS position (if available) using the configured time interval (as-
suming network and GPS time synchronization is given). The time interval can only be set
an integer multiple of the scheduling round time (see "Standard (Scheduled) Transmission"
on p. 5.8).
If a controller has never received the GPS signal (required for scheduled transmissions), it
cannot transmit an auto push configuration request.
It should be noted that transmitting a dynamic Auto Push Configuration Request will override
the Auto Push Time settings as configured by R&S RNMS3000. Thus, if the Auto Push
(Time) operation has for example been disabled in the R&S RNMS3000 mission planning
and the radio receives a dynamic APR request from a controller, the dynamic setting will be
remembered by the radio. Thus, the radio may start an Auto Push Time operation according
to the last APR configuration request (even if the initial mission planning had disabled APT)
when the radio is switched to this preset page next time. Hence, it is the responsibility of the
controller's operator to ensure that an APR operation (of a temporary nature) is disabled (by
sending an APR/APT=0 request to all radios) if the resumption of automatic reporting is not
desired (when the radio is switched on next time).
Standard (Scheduled) Transmission
On the radio, a transmission scheduling scheme has been implemented in order to prevent
multiple GPS participants transmitting on the air channel at the same time (either accidental-
ly or incidentally). There is a potential for collisions between push, pull and auto push GPS
data being transmitted concurrently. Also, collision potential exists between GPS and other
services like voice / data and network service transmissions. Collisions of GPS data with oth-
er services cannot be avoided by the scheduling.
In order to prevent the problem of on-air collisions, a scheduling scheme is applied to stan-
dard (i.e. non-immediate) GPS transmissions. In SECOM-P and SECOM-V these GPS
transmissions occupy the air channel for less than one second. Hence, the scheduling round
time (for one scheduling cycle) is equal to the number of GPS participants configured by
R&S RNMS3000.
5.8
Types of GPS Transmission
Operating Manual 6175.4760.02 – 01
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