ZED-F9K - Integration manual
u-blox receivers allow users to independently choose GNSS signals used in the receiver
(using CFG-SIGNAL-*) and the input/output time base (using CFG-TP-*). For example it
is possible to instruct the receiver to use GPS and GLONASS satellite signals to generate
BeiDou time. This practice will compromise timepulse accuracy if the receiver cannot
measure the timing difference between the constellations directly and is therefore not
recommended.
The information that allows GNSS times to be converted to the associated UTC times is
only transmitted by the GNSS at relatively infrequent periods. For example GPS transmits
UTC(USNO) information only once every 12.5 minutes. Therefore, if a time pulse is
configured to use a variant of UTC time, after a cold start, substantial delays before the
receiver has sufficient information to start outputting the time pulse can be expected.
3.9.10.4 Time pulse configuration
u-blox ZED-F9K receivers provide a time pulse (TIMEPULSE) signal with a configurable pulse period,
pulse length and polarity (rising or falling edge).
It is possible to define different signal behavior (i.e. output frequency and pulse length) depending
on whether or not the receiver is locked to a reliable time source. Time pulse signal can be configured
using the configuration group CFG-TP-*.
3.9.10.5 Configuring time pulse with CFG-TP-*
The configuration group CFG-TP-* can be used to change the time pulse settings, and includes the
following parameters defining the pulse:
•
timepulse enable
- If this item is set, the time pulse is active.
•
frequency/period type
- Determines whether the time pulse is interpreted as frequency or
period.
•
length/ratio type
- Determines whether the time pulse length is interpreted as length [us] or
pulse ratio [%].
•
antenna cable delay
- Signal delay due to the cable between the antenna and the receiver.
•
pulse frequency/period
- Frequency or pulse time period when locked mode is not configured or
active.
•
pulse frequency/period lock
- Frequency or pulse time period, as soon as the receiver has
calculated a valid time from a received signal. Only used if the corresponding item is set to use
another setting in locked mode.
•
pulse length/ratio
- Length or duty cycle of the generated pulse, either specifies a time or ratio
for the pulse to be on/off.
•
pulse length/ratio lock
- Length or duty cycle of the generated pulse, as soon as the receiver
has calculated a valid time from a received signal. Only used if the corresponding item is set to
use another setting in locked mode.
•
user delay
- The cable delay from the receiver to the user device plus signal delay of any user
application.
•
lock to GNSS freq
- If this item is set, uses the frequency gained from the GNSS signal
information rather than the local oscillator's frequency.
•
locked other setting
- If this item is set, the alternative setting will be used as soon as the
receiver can calculate a valid time. This mode can be used, for example, to disable time pulse if
the time is not locked, or to indicate a lock with different duty cycles.
•
align to TOW
- If this item is set, pulses are aligned to the top of a second.
•
polarity
- If set, the first edge of the pulse is a rising edge (pulse polarity: rising).
•
grid UTC/GNSS
- Selection between UTC (0), GPS (1), GLONASS (2) and BeiDou (3) timegrid.
Also affects the time output by UBX-TIM-TP message.
The maximum pulse length cannot exceed the pulse period.
UBX-20046189 - R01
3 Receiver functionality
Page 59 of 105
C1-Public
Early production information
