Rtd_v1_xmt

Three messages are transmitted as part of the real time display data stream. The messages are distinguished by the first 2 bytes (SHORT) in the message summarized in the list table (see sig_rtdisp.h):

• RTRAY_TYPE_HEADER
• RTRAY_TYPE_RAY
• RTRAY_TYPE_RAY

The message RTRAY_TYPE_HEADER consists of the 2-byte ID followed by a struct rtd_v1_vol_header. This message is sent either at the beginning of a new elevation sweep, or periodically if a new sweep has not started recently.

The message RTRAY_TYPE_RAY begins with the 2-byte ID. What follows depends on the type of data being transmitted by the real time display sender. This is chosen in the sender's setup utility and can consist of 1, 2, or 3 data types being Z, V, or W. The volume header indicates which data types are currently transmitted and in which order the data types are presented.

For example, if only Z and V are transmitted, the RTRAY_TYPE_RAY message consists of its 2-byte message ID, followed by a struct rtd_v1_ray_header, followed by the data elements for Z, followed by the V elements. The Z and V elements are presented as one byte per range bin.

For example, if the volume header indicates that 200 bins of each type are transmitted, then the Z elements (and the V elements) are each 200 bytes long, with each byte representing 1 range bin. The spacing between the range bins is also defined by the volume header.

For information on element scaling, see Data Types.