D Logs summary
MiLLennium Command Descriptions Manual 181
1 This bit will be set to 1 when the digital signal processors (DSP) have passed the self-test requirements.
0 If this bit is set to 0, one or both of the DSP chips has failed self-test; please contact NovAtel Customer
Service.
Bit 5 L1 AGC
1 When set to 1, the L1AGC circuits are operating within normal range of control.
0 This bit will be set clear if the L1AGC is operating out of normal range. Failure of this test could be the
result of various possibilities, such as: bad antenna LNA, excessive loss in the antenna cable, faulty RF
downconverter, or a pulsating or high power jamming signal causing interference. If this bit is
continuously set clear, and you cannot identify an external cause for the failed test, please contact NovAtel
Customer Service.
Bit 6 COM1
1 When set to 1, the COM1 UART has passed the self-test requirements.
0 If set to 0, the COM1 UART has failed self-test and cannot be used for reliable communications.
Bit 7 COM2
1 When set to 1, the COM2 UART has passed the self-test requirements.
0 If set to 0, the COM2 UART has failed self-test and cannot be used for reliable communications.
Bits 8, 9, 10 Week / No Coarsetime / No Finetime
0 These bits indicate the state of the receiver time and are set only once, generally in the first few minutes
of operation, in the presence of adequate numbers of satellite signals to compute position and time.
1 If these bits are not all set to zero, then the observation data, pseudorange measurement, carrier phase, and
Doppler measurements may jump as the clock adjusts itself.
Bit 11 L1 Jammer Detection
0 Normal operation is indicated when this bit is 0.
1 If set to 1, the receiver has detected a high power signal causing interference. When this happens, the
receiver goes into a special anti-jamming mode where it re-maps the A/D decode values as well as special
L1AGC feedback control. These adjustments help to minimize the loss that will occur in the presence of a
jamming signal. You should monitor this bit, and if set to 1, do your best to remedy the cause of the
jamming signal. Nearby transmitters or other electronic equipment could be the cause of interference;
you may find it necessary to relocate your antenna position if the problem persists.
Bits 12, 13, 14 Buffer COM 1 / COM 2
0 Normal operation is indicated by a 0 value.
1 These bits are set to 1 to inform the user when any of the 8-Kbyte output buffers have reached an over-
run condition (COM1 or COM2). Over-run is caused by requesting more log data than can be taken off the
GPSCard because of bit rate limitations or slow communications equipment. If this happens, the new data
attempting to be loaded into the buffer will be discarded. The receiver will not load a partial data record
into an output buffer. The flag resets to 0 five minutes after the last ov errun occurred.
Bit 15 CPU Overload
0 Normal operation is indicated by a 0 value.
1 A value of 1 indicates that the CPU is being over-taxed. This may be caused by requesting an excessive
amount of information from the GPSCard. If this condition is occurring, limit redundant data logging or
change to using binary data outpu t formats, or both. You should attempt to tu ne the logging requirements
to keep the idle time above 20% for best operation. If the average idle % drops below 10% for prolonged
periods of time (2-5 seconds), critical errors may result in internal data loss and the over-load bit will be
set to 1. You can monitor the CPU % idle time by using the RvSA log messag e. The flag resets to 0 fi ve
minutes after the first overload occurred.
Note: As the amount of CPU power becomes limited, the software will begin to slow down the position
calculation rate. If the CPU becomes further limited, the software will begin to skip range measurement
processing. Priority processing goes to the tracking loops.