$DVKFC Kalman Filter Raw Data Support Message

When you want to use Tracker 650 input into your own system Kalman Filter, we supply the $DVKFC data message.

Format:

$DVKFC,id,seq,dt,tod,[A],cg,pc,ra,rc,vv,vc,[B],cg,pc,ra,rc,vv,vc,[C],cg,pc,ra,rc,vv,vc,0x0055AAFF*cs

Example:

$DVKFC,24577,35060,0.100000,3801.552000,[A],60,1000,0.500000,4.381214,0.000000,6.283185,[B],60,1000,0.500000,3.450820,0.000000,6.283185,[C],60,1000,0.500000,3.839504,0.000000,6.283185,0x0055AAFF*2A

Fields are listed below.

Field: id. Message version. The version described here is "24577". If the version number is changed, you may need to come back here and make sure your parser is still valid.

Field: seq. Sequence Number, an unsigned 32 bit number that starts at 0 and increments by 1 each time a message is sent.

Field: dt. Delta-Time, a floating point number denoting the number of seconds of time included in this measurement. Standard values are 0.05, 0.1, and 0.2, although other values are possible.

Field: tod. System-Time, a floating point number denoting the system clock value in seconds, which starts at 0 at boot-up and counts up.

Field [A]. Marks the start of six data fields for sensor channel A.

Each sensor channel includes the following data, in this order:

1. Field: cg. Channel gain, integer given in dB.

2. Field: pc. Ping cycles. Length of outgoing ping, in cycles.

3. Field: ra. Slant range along sensor axis to intersection with target plane, a floating point number. This ranges from 0.1 to 25 meters.

4. Field: rc. Range confidence. A floating point number denoting the ratio of the power of the detected ping to the noise floor surrounding the detected ping. Generally, any value under 25.0 is definitely a false detection.

5. Field: vv. Velocity along the sensor cone's axis, a floating point number. This ranges from about -10 m/s to +10 m/s. A positive velocity means the sensor is approaching the reflecting object.

6. Field: vc. Velocity confidence, a floating point number denoting the quality of the detected ping. Velocity confidence is a measure of the variance of a synthesized Doppler signal (based on the parameters of measurement) compared to the measured signal. This ranges from 0 to 2*pi. A variance larger than about 0.5 indicates the reflected ping is not well-enough formed to be usable.

Field [B]. Marks the start of six data fields for sensor channel B. The fields are in the same order and have the same definition as the data fields for sensor channel A.

Field [C]. Marks the start of six data fields for sensor channel B. The fields are in the same order and have the same definition as the data fields for sensor channel A.

If this message were to come from a four-channel sensor such as the DVL-75, sensor channel D would follow in the same format as the other three channels.

Field 0x0055AAFF. End-of-message tag, an unsigned 32 bit number that should have the value 0x0055AAFF. This has no purpose other than an indication that you have counted the preceding fields properly.

Channel Assignments for Tracker 650, looking at sensor face

Channel Assignments for DVL-75 all-in-one and most-in-one configurations, looking at sensor face

Channel Assignments for DVL-75 separate head configuration, looking at sensor face

Sensor labeling: Looking at the sensor face of the unit, the arrow points at channel A. Still looking at the face, channel B is 120 degrees clockwise from channel A. Channel C is 120 degrees counter-clockwise from channel A.