Parameter

Number of

bits

Description

Encryption

Status

Function ID

5

3 = Overlay, Option 2

AES encrypted

Overlay Type

4

0-3 = not allowed [for use with FID 2]

4 = Track Line Search Pattern or Route; 5 = Polygon

6 = not allowed [for use with FID 2]; 7-15 = undefined

AES encrypted

Overlay Number

5

Sender generated (0-31)

AES encrypted

Origin Longitude

25

Longitude to nearest 1/1000 min (±180 degrees; East = positive; West = negative; 181 degrees = not available = default) [± 1.8 meter accuracy]

AES encrypted

Origin Latitude

24

Latitude to nearest 1/1000 min (±90 degrees; North = positive; South = negative; 91 degrees = not available =

default) [± 1.8 meter accuracy]

AES encrypted

Number of Additional Waypoints

4

Number of additional waypoints for a Track Line or polygon overlay (maximum = 15);

AES encrypted

Additional Waypoints

– Maximum of 15

Each: Lon = 25

Lat = 24

Up to 735 bits

Longitude to nearest 1/1000 min (±180 degrees; East = positive; West = negative; 181 degrees = not available = default) [±1.8 m accuracy

Latitude to nearest 1/1000 min (±90 degrees; North = positive; South =

negative; 91 degrees = not available = default) [±1.8 m accuracy]

AES encrypted

Search Speed

10

Specified search speed in knots;

0 = default = not applicable/specified.

AES encrypted

Search Altitude

12

Specified search altitude in feet;

0 = default = not applicable/specified.

AES encrypted

Unused bits set to zero

Variable

Unused bits set to zero are inserted so that the number of bits in the encrypted field is a multiple of 128 bits.

AES encrypted

Checksum

16

Cyclic Redundancy Check (CRC) 16-bit polynomial

AES encrypted

TOTAL

128

256

384

512

640

768

896

128, 256, 384, 512, 640, 768 or 896

encrypted bits

AES encrypted