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Products > Lodestar (Subsea) AHRS and Acoustically Aided INS
- Overview
- Features & Benefits
- Technical Specifications
- PDF Datasheet
- Related Products
- - Lodestar Surface AHRS and AAINS
- - Lodestar GyroUSBL
- - Lodestar GyroCompatt
- - Radian AHRS
- Overview
- Lodestar is a solid state IMO approved Attitude and Heading Reference System (AHRS) and Acoustically Aided Inertial Navigation System [AAINS]. The unit is comprised of three high grade, high reliability, commercially available, Ring Laser Gyros (RLG) and three accelerometers. A Sonardyne developed gyrocompass algorithm runs in the background even when used as an AAINS.
Lodestar AHRS can be supplied to suit subsea applications at any depth. With the supplied battery back up capability, the unit is able to continue running the AHRS and AAINS algorithms during vehicle power brown-outs.
The Lodestar AHRS algorithm outputs precise heading, roll, pitch and heave estimation in dynamic conditions without the need for external aiding inputs or vessel manoeuvres.
Lodestar is the core component in any Sonardyne AAINS system. It powers and directly interfaces to aiding sensors such as a USBL or LBL transceiver, a DVL, a GNSS receiver, a pressure sensor and a sound speed sensor (SSS).
- Applications Include:
- - An optimised USBL system: The directly coupled precise attitude data complements the precision of advanced USBL systems
- As a precise position input to DP systems using AAINS, a USBL system and one or more seabed reference beacons for operations in excess of 2000 metres
- As a positioning system for an ROV, aided by a combination of position estimates from a topside USBL system, vehicle mounted DVL, pressure, sound speed and LBL transceiver (subsea option)
- Multi-beam Surveys
- Features & Benefits
- Single box solution for motion sensor and gyrocompass
- AAINS capability
- Choice of depth ratings: 1,000 3,000, 5,000 metres
- Surface version available
- <5 minute settling time
- 0.1 heading accuracy unaided
- 0.01 roll & pitch accuracy
- 5cm / 5% heave accuracy
- Fast follow up speed of 500/Sec
- Ethernet interface
- Transport approved Li-Ion battery back up as standard
- On board 8GB memory (Expandable to 32GB)
- No dedicated GPS string required
- MTBF RLG >300,000 hours MTBF Lodestar >50,000 hours
- Designed and Approved to IMO Resolution A424(XI)
Technical Specifications
| Feature | Type 8084_000_1110 | Type 8084_000_3110 | Type 8084-000-5310 | ||
|---|---|---|---|---|---|
| Attitude | Heading | Range | 0-360° | 0-360° | 0-360° |
| Accuracy | 0.10° secant latitude rms | 0.10° secant latitude rms | 0.10° secant latitude rms | ||
| Settle Time | <5 minutes | <5 minutes | <5 minutes | ||
| Follow Up Speed | 500º / Second | 500º / Second | 500º / Second | ||
| Resolution | 0.01º | 0.01º | 0.01º | ||
| Roll & Pitch | Range | ±180º (no physical limit) | ±180º (no physical limit) | ±180º (no physical limit) | |
| Accuracy | 0.01º | 0.01º | 0.01º | ||
| Resolution | 0.01º | 0.01º | 0.01º | ||
| Heave | Range | ±99m | ±99m | ±99m | |
| Accuracy (Real Time) | 5cm or 5% whichever the greater | 5cm or 5% whichever the greater | 5cm or 5% whichever the greater | ||
| Bandwidth | User Selectable | User Selectable | User Selectable | ||
| Resolution | 0.01m | 0.01m | 0.01m | ||
| Physical | Size | 211mm Dia. x 375mm | 214mm Dia. x 405mm | 205mm Dia. x 409mm | |
| Weight in Air / Water | 13kg / 2.9kg | 39kg / 28kg (estimate) | 39kg / 28kg (estimate) | ||
| Mechanical Construction | Anodised Aluminium | Super Duplex S-Steel | Super Duplex S-Steel | ||
| Environmental | Operating Temperature | -10°C to +55°C | -10°C to +55°C | -10°C to +55°C | |
| Shock Rating Operational | 22g, 11ms half sine | 22g, 11ms half sine | 22g, 11ms half sine | ||
| Depth Rating | 1,000 metres | 3,000 metres | 5,000 metres | ||
| Power Requirement | 20–50V DC, 15W nominal, 20W max | 20–50V DC, 15W nominal, 20W max | 20–50V DC, 15W nominal, 20W max | ||
| Back Up Battery Type / Life | Li-Ion / 3 hours | Li-Ion / 3 hours | Li-Ion / 3 hours | ||
| Data Storage (Onboard Memory) | 8GB (Expandable to 32GB) | 8GB (Expandable to 32GB) | 8GB (Expandable to 32GB) | ||
| Digital Output | Number of Digital Ports / Protocol | Digital Ports / RS232 or RS485 | 4 Digital Ports / RS232 or RS485 | 4 Digital Ports / RS232 or RS485 | |
| Other Ports | 1 x Ethernet | 1 x Ethernet | 1 x Ethernet | ||
| Power Output | Number of Power Ports | 2 x 48V DC and 1 x 12V DC 0.5W output | 2 x 48V DC and 1 x 12V DC 0.5W output | 2 x 48V DC and 1 x 12V DC 0.5W output | |
| AAINS | Navigation Error (Scenario and Aiding Dependent) | ||||
| Navigation Error (Free Inertial) | Typically 10 metres, 4 minutes after loss of aiding | Typically 10 metres, 4 minutes after loss of aiding | Typically 10 metres, 4 minutes after loss of aiding | ||
| Maximum Acceleration | 2.5g or 5.0g | 2.5g or 5.0g | 2.5g or 5.0g | ||