Navman 11 User Manual

40

MN002000A © 2004 Navman NZ Ltd. All rights reserved. Proprietary information and specifications subject to change without notice.

Message ID: 1221
Rate: as required (maximum rate is 1 Hz)
Message length: 15 words

1-4

Message header

5

Header checksum

6

Sequence number (Note 1)

I

0 to 32 767

7.0

Held altitude disable (default = enabled)

Bit

0 = enabled

1 = disabled

7.1

Ground track smoothing disable (default = 

enabled)

Bit

0 = enabled

1 = disabled

7.2

Position pinning disable (default = enabled)

Bit

0 = enabled

1 = disabled

7.3

Disable low quality measurements (Note 2)

Bit

0 = enabled

1 = disabled

7.4

Enable jamming detect

Bit

0 = enabled

1 = disabled

7.5-7.15

Reserved (must be zeroed out)

Bit

0

8-14

Reserved (must be zeroed out)

15

Data checksum

Note 1: The sequence number is a count that indicates whether the data in a particular binary message has been updated or 

changed since the last message input.

Note 2: When this bit is set, the receiver will only use “perfect” measurements (ie measurements without any errors in tracking 

status or data). If the bit is not set, the system uses measurements that, while not perfect, are still good enough to use under SPS 

conditions.

Message ID: 1300
Rate: as required (maximum rate approximately 0.1 Hz)
Message length: 8 words

1-4

Message header

5

Header checksum

6

Sequence number (Note 1)

I

0 to 32 767

7

Reserved

8

Data checksum

Note 1: The sequence number is a count that indicates whether the data in a particular binary message has been updated or 

changed since the last message input.

This message allows the user to control various 

features in the navigation processing. The held 

altitude disable bit controls the use of stored 

GPS-based altitude to aid the receiver when the 

vertical geometry deteriorates. The ground track 

smoothing bit controls the use of satellite range 

bias estimates to minimise the position shifts 

resulting from SA and constellation changes. The 

position pinning bit controls the use of a horizontal 

speed test to pin the position reported by the 

receiver and eliminate the wander associated with 

SA when static. 

Ground track smoothing and position pinning are 

not used when DGPS corrections are in use. The 

contents of the ‘nav configuration’ message are 

described in Table 3-33.

This message instructs the receiver to immediately 

execute its Built-In Test (BIT). Results of the BIT 

are available in the BIT results message. The 

contents of the ‘perform built-in test command’ 

message are described in Table 3-34.