User's Manual

5 Setting up the Receiver

58 SPSx50 Modular GPS Receiver User Guide

Setting up a pair of SPSx50 GPS receivers to provide heading

The SPS550H receiver is permanently in Heading mode and, when combined with a

suitable Trimble receiver, provides GPS heading. Other SPSx50 GPS receivers can be

used for heading only if they can operate in Heading mode (see Configuring the

receiver pair, page 64).

The SPS550H is a dual-frequency GPS receiver with a dual-frequency antenna, but it

does not operate as a stand-alone DGPS receiver. To compute a true north heading and

to be capable of positioning, the receiver requires an output message from another

SPSx50 receiver. To determine the precise vector between two moving objects, pair the

SPS550H heading add-on with any one of the following SPSx50 receivers:

• SPS550

• SPS750 Max

• SPS850

Connect the antenna on the SPS550H to the other SPSx50 receiver to determine the

precise GPS heading between the two antennas. The SPS550H GPS receiver displays

the heading on the two-line display, and outputs the heading data in NMEA or binary

format.

Tip – To create a single, compact GPS position and heading unit, use the mounting frame

provided to stack the SPS550H GPS receiver on top of another SPSx50 GPS receiver. See

below. Use the Marine Heading Cable (P/N 57169) provided.

The Moving Baseline RTK positioning technique

In most RTK applications, the reference receiver remains stationary at a known

location and the rover receiver can move. However, Moving Baseline RTK is an RTK

positioning technique in which both reference and rover receivers can move about.

Moving Baseline RTK is useful for GPS applications that require vessel orientation.

Figure 5.9 Vessel heading from Moving Baseline RTK

to be done

Antenna