Remotely Operated Vehicles (ROVs)

Remotely Operated Vehicles (ROVs) Downloads » ROV App Note  — Magnetometer Installation  Normally, small submersibles are stabilized by the pilot’s actions in response to the orientation of the sub. In the case of an ROV, the pilot is not on board so there is no human “feel” for the orientation of the vehicle. This situation can lead to damage or loss of the submersible. Since the cost of the vehicles as well as the expense of at-sea operations is quite high, a sensor package is necessary that can reliably transmit accurate data on the attitude of the sub. Remotely operating a submersible requires a full attitude gyro sensor. Heading data is necessary to navigate the vehicle to its destination. Pitch and roll data is also required to provide an accurate picture of the vehicle’s orientation. Other important features of the gyro package are wide bandwidth, low power consumption, and high reliability. Watson Industries offers the Attitude and Heading Reference System (AHRS) for this application. The AHRS provides bank, elevation and heading data. Additionally, the AHRS can output roll, pitch and yaw rates, X, Y and Z accelerations and X, Y and Z magnetometer data if requested.   Watson Experience Watson Industries has been manufacturing Attitude and Heading Reference Systems (AHRS) for this application since 1993.   Applicable Products AHRS-E304 AHRS-S305 SHR-E360 SHR-S360 Technical Challenges The primary problem with providing an attitude gyro sensor for this application is the difficult magnetic environment of the submersible. Undersea vehicles cannot use GPS for their heading reference, so a magnetometer is required. The problem with using magnetometers in submersibles is that they have large steady...

Yacht and Ferry Stabilization

Yacht and Ferry Stabilization Downloads » Yacht Stabilization Application Note  Ocean-going yachts and ferries are susceptible to rolling and pitching with waves. To minimize the effects of wave motions on the passengers and cargo, a sensor is needed that can provide the necessary information to an active stabilization system. Yachts are stabilized primarily to provide additional comfort to the passengers. The main purpose of stabilizing ferries is safety related. The roll angle of the vessel is controlled so that any cargo stored inside will not shift. These applications require a high quality, reliable vertical reference gyro that can survive for extended periods in a marine environment. Our VRS line of vertical references is ideal for this application. It provides roll angle output data in both analog and digital formats. The ADS line of vertical references provide roll angle data in analog format only. These sensors have provided accurate data and reliable performance for customers in this field for many years.   Watson Experience Watson Industries has been involved in the development and production of vertical gyro products for this application since 1982. Applicable Products VRS-E232-1AD ADS-C232-1A Pro Gyro® Rate Gyros ARS Rate Gyros Technical Challenges A vertical reference mounted on a ship susceptible to oscillations generated by wave motion. This makes it very difficult to sense vertical, because the dynamics of the application are better compensated for by a long time constant, but removing these errors quickly requires a short one. This problem is overcome with Watson Industries proprietary data processing algorithms and our variable time constant settings. The Watson VRS line of vertical references is a microprocessor based system...

Marine Communications Satellite Tracking Antenna Stabilization

Marine Communications Satellite Tracking Antenna Stabilization Downloads » Satellite Tracking Application Note  A ship rolling and pitching in the sea proves to be a difficult dynamic environment. Satellite antennas in such applications require gyro stabilization in order to accurately receive or transmit data. These antennas can only accommodate a small amount of pointing error before being rendered unable to communicate with the satellite. In the past, many types of gyros have been used for this application, with varying degrees of success: e.g. dynamically tuned gyros are very stable, but have reliability problems; fiber optic gyros have been used, but stability in the environment is an issue. Watson Industries manufactures reliable triaxial gyros for use in stabilization systems that provide accurate performance while operating for extended times in an extreme environment. The ARS-E322-1A/80 provides accurate triaxial rate data as an analog voltage and a digital RS-232 signal.   Watson Experience Watson Industries has built gyro packages for antenna stabilization since 1982.   Applicable Products ARS-E322-1A/80 ARS-E322/222 DMS-EGP02 DMS-SGP02 Technical Challenges Reliability and accurate rate output over long operating periods are the primary obstacles to providing gyros for this application. Watson Industries has built algorithms into our gyro packages that actively correct for errors. This operation will keep the gyro accuracy well within requirements for the life of the product.   Requirements Low Noise: <0.03° /sec Wide Bandwidth: 80Hz Rate Range: ±50° /sec Shock: 200G Vibration: 5G RMS Operating Temperature: -30° C to +70° C Typical Options We are able to accommodate your custom needs. Go to our custom product modifications page for a listing of the most common custom options we...

Buoy and Current Monitoring

Buoy and Current Monitoring Downloads » Current Monitoring Application Note  — Magnetometer Installation  When a scientific data monitoring sensor is placed into a buoy, a reliable device that can remain in the field for many months at time is needed. Selecting a sensor for a buoy or current monitoring package can be a difficult task. This is especially true when the device is to be used at high magnetic latitudes near the north pole. Watson Industries manufactures the SHR series of strapdown heading reference sensors that are well suited for this application. The SHR-360 provides the accurate heading data that is needed for current monitoring. Additionally, the SHR can output bank, elevation, X, Y and Z acceleration and X, Y and Z magnetometer data if requested.   Watson Experience Watson Industries has been manufacturing SHR heading references for this application since 1998.   Applicable Products SHR-360 SHR-S360 SHR-E360 Technical Challenges There are several challenges that are involved with deploying a sensor for months at a time in a buoy. A good sensor calibration system is necessary. This is because the sensor must resolve signals that are smaller than the magnetic field of the buoy. It is essential that the sensor be highly reliable because the device will not be able to be maintained. Low power consumption is also a must for similar reasons. The lower the power usage, the smaller the package can be as a whole, and the longer the package can remain deployed. Any installation at high magnetic latitudes makes sensitivity a major issue since a small error in detecting the magnetic field can result in major changes to...

Undersea Cable Laying Instrumentation

Undersea Cable Laying Instrumentation Downloads » Cable Laying App Note  — Magnetometer Installation  Since a remotely piloted robotic cable burying machine, sometimes called a trencher, can cost several million dollars, the safety of the machine is of utmost importance. Secondly, consistent productivity and trouble-free operation is a primary concern because the cost of at-sea operations can approach $100,000 per day. Piloting the trencher requires a full attitude sensor. Heading data is necessary to navigate the vehicle to the site. Pitch and roll data is required to assure the robot maintains a level orientation in transit and once it begins burying operations. Watson Industries manufactures an Attitude and Heading Reference System (AHRS) that is perfectly suited for this highly technical application. The Watson AHRS provides bank, elevation and heading data. Additionally, the AHRS can output roll, pitch and yaw rates, X, Y and Z accelerations and X, Y and Z magnetometer data if requested.   Watson Experience Watson Industries has been manufacturing attitude and heading reference systems since 1993. We have produced AHRS specifically for this application since 1999.   Applicable Products AHRS-E304 AHRS-S305 SHR-E360 SHR-S360 Technical Challenges The primary difficulty in providing a sensor for this application is the difficult magnetic environment of the trencher. Undersea vehicles cannot use GPS for their heading reference, so a magnetometer is required. The problem with using magnetometers in this application is that cable laying vehicles have large steady state magnetic fields and also create large variable magnetic fields. Magnetometers provide a heading reference by sensing the Earth’s magnetic field. This means that any extraneous magnetic fields in the vicinity will induce heading errors. Cable...