ELEVATIONCUTOFF

Sets the elevation cut-off angle for tracked satellites

Platform:

OEM719, OEM729, OEM7500, OEM7600, OEM7700, OEM7720, PwrPak7, CPT7, CPT7700, SMART7, SMART2

The ELEVATIONCUTOFF command is used to set the elevation cut-off angle for tracked satellites. The receiver does not start automatically searching for a satellite until it rises above the cut-off angle (when the satellite position is known). Tracked satellites that fall below the cut-off angle are no longer tracked unless they are manually assigned (refer to the ASSIGN command).

In either case, satellites below the elevation cut-off angle are eliminated from the internal position and clock offset solution computations.

This command permits a negative cut-off angle and can be used in the following situations:

The antenna is at a high altitude and thus can look below the local horizon
Satellites are visible below the horizon due to atmospheric refraction

Care must be taken when using ELEVATIONCUTOFF command because the signals from lower elevation satellites are traveling through more atmosphere and are therefore degraded. Use of satellites below 5 degrees is not recommended.

This command combines the following commands into one convenient command: ECUTOFF, GLOECUTOFF, GALECUTOFF, QZSSECUTOFF, SBASECUTOFF, BDSECUTOFF and NAVICECUTOFF.

For dual antenna receivers, this command applies to both the primary and secondary antennas.

A low elevation satellite is a satellite the receiver tracks just above the horizon. Generally, a satellite is considered low elevation if it is between 0 and 15 degrees above the horizon.

There is no difference between the data transmitted from a low elevation satellite and that transmitted from a higher elevation satellite. However, differences in the signal path of a low elevation satellite make their use less desirable. Low elevation satellite signals have more error due to the increased amount of atmosphere they must travel through. In addition, signals from low elevation satellites don't fit the assumption that a signal travels in air nearly the same as in a vacuum. As such, using low elevation satellites in the solution results in greater position inaccuracies.

The elevation cut-off angle is specified with the ELEVATIONCUTOFF command to ensure that noisy, low elevation satellite data below the cut-off is not used in computing a position. If post-processing data, it is still best to collect all data (even that below the cutoff angle). Experimenting with different cut-off angles can then be done to provide the best results. In cases where there are not enough satellites visible, a low elevation satellite may actually help in providing a useful solution.

Message ID: 1735

Abbreviated ASCII Syntax:

ELEVATIONCUTOFF Constellation Angle [Reserved]

Factory default:

ELEVATIONCUTOFF ALL 5.0 0

ASCII Example:

ELEVATIONCUTOFF GPS 5

ELEVATIONCUTOFF ALL 5

Field	Field Type	ASCII Value	Binary Value	Description	Format	Binary Bytes	Binary Offset
1	Command header	-	-	ELEVATIONCUTOFF header This field contains the command name for abbreviated ASCII or the message header for ASCII or Binary.	-	H	0
2	Constellation	GPS	0	Sets the cut-off angle for GPS Constellation satellites only.	Enum	4	H
		GLONASS	1	Sets the cut-off angle for GLONASS constellation satellites only.
		SBAS	2	Sets the cut-off angle for SBAS constellation satellites only.
		GALILEO	5	Sets the cut-off angle for Galileo constellation satellites only.
		BEIDOU	6	Sets the cut-off angle for BeiDou constellation satellites only.
		QZSS	7	Sets the cut-off angle for QZSS constellation satellites only.
		NAVIC	9	Sets the cut-off angle for NavIC constellation satellites only.
		ALL	32	Sets the cut-off angle for all satellites regardless of the constellation.
3	Angle	±90.0 degrees		Elevation cut-off angle relative to the horizon.	Float	4	H+4
4	Reserved	0		Reserved Field (optional)	Ulong	4	H+8