User's Guide

APPENDIX B - PACKED BINARY TARGET RETURN FORMAT

The following sequence of numbers FC00000000000 characterizes target returns from 50 1-foot

range bins represented in a packed binary format. This format allows a simple form of data

compression to be processed in the SPIDER-650 unit while reducing the bottleneck of RS-232

data transfer. Each ASCII hexadecimal digit represents returns from four contiguous, 1-foot

range bins. The last ASCII hexadecimal digit will only represent the last two contiguous, 1-foot

range bins and will always be either 0, 8, 4, or C.

The most significant hexadecimal digits represent targets that are closer to the radar unit. For

example, let’s assume the following sequence of hexadecimal digits FC00000080000 were sent

over the RS-232 link and displayed on the terminal. The first hexadecimal digit ‘F’ (binary 1111)

designates that there were target returns at 1, 2, 3, and 4-foot intervals from the receiver since

each of the four bits were set in the respective range locations. The second hexadecimal digit ‘C’

(binary 1100) denotes there were target returns at 5 and 6 foot intervals from the receiver but

none were detected at the 7 and 8 foot intervals since these range locations have cleared bits. The

only other range location to be detected was at 33 feet since the 33

bit from the left is the only

other one set (the hexadecimal 8 digit).