All HiPAP models now include the Cymbal acoustic protocol which utilises wideband Direct Sequence Spread Spectrum (DSSS) signals.
The Cymbal protocol transmits more energy into the water and together with the uniqueness coding the following new advantages of the HiPAP systems are made available:
- Increases angular accuracy with up to 30% (SSBL improvement)
- Longer range capability
- Range accuracy is in the order of 0.02m (0,01m between cNODE transponders)
- More than 500 additional unique transponder channels in addition to the "older" 56 FSK channels
- Improvement of multi path properties
- Allows higher position update rate through MultiPing
- Automatically adjustment of transponder TX power for increased battery endurance
- High speed telemetry data rate (max 8kbit/s)
- Supports variable telemetry data rate and high reliability level
- Telemetry data will be interleaved between the positioning signals
- Enables modeless change of transponders from SSBL and LBL and vice versa
The position accuracy for LBL operation depends on the transponder array geometry, sound velocity errors and signal to noise ratio. Range accuracy's down to a few centimetres can be obtained, while
ROV and vessel positions can be calculated to within a few decimetres. The graph shows improvement in horizontal position error between continuous wave and Cymbal.