Users manual
NR7000
Revision #:
B
Date:
102121
Page #:
14 of 24
www.novuspower.com
The receiver will now know that it lies somewhere on the circle
of points produced where these two spheres intersect.
When a third satellite is detected and a range determined, a
third sphere intersects the area formed by the other two. This
intersection occurs at just two points. A fourth satellite is then
used to synchronize the receiver clock to the satellite clocks.
In practice, just four satellite measurements are sufficient for
the receiver to determine a position, as one of the two points
will be totally unreasonable (possibly many kilometers out into
space). This assumes the satellite and receiver timing to be
identical. In reality, when the receiver compares the incoming
signal with its own internal copy of the code and clock, the two
will no longer be synchronized. Timing error in the satellite
clocks, the receiver, and other anomalies, mean that the
measurement of the signal transit time is in error. This,
effectively, is a constant for all satellites since each
measurement is made simultaneously on parallel tracking
channels. Because of this, the resulting ranges calculated are
known as “pseudo-ranges”.
To overcome these errors, the receiver then matches or
“skews” its own code to become synchronous with the satellite
signal. This is repeated for all satellites in turn, thus measuring
the relative transit times of individual signals. By accurately
knowing all satellite positions, and measuring the signal transit
times, the user’s position can be accurately determined.
The GNSS lock status can be monitored on the RS232/serial
connector.
If the GNSS indicator remains unlocked for an extended period
of time, it could be an indication of an antenna, cabling or unit
malfunction. Confirm the antenna is still connected and has not
become obstructed from a clear view of the sky. To check the
unit, an alternate antenna can be tried in order to isolate the
malfunction. For further support, please contact the factory at
866-313-9401.
