Ohmex Sonarmite 'HPR' - Integrated System

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The SonarMite Echo Sounder is the result of nearly two years research and development to further extend the boundaries of shallow water hydrographic surveying equipment. The introduction by Ohmex in 1997 of the SonarLite, the worlds first truly portable echo sounder system, has been a hard act to follow and it remains the portable instrument of choice in many survey companies around the world. The release of the SonarMite instrument marks the next stage introducing a series of equipment designed around the WinSTRUMENT concept using the latest portable computers integrated with new measurement technologies.

SonarMite HPR
The SonarMite HPR is in the same case style and battery capacity as the SonarMite BT but also includes a six axis accelerometer device to calculate Heave Pitch and Roll parameters.

The purpose of including the HPR data is to compensate for typical attitude movement in a small boat system such as offset of an RTK antenna due to pitch and roll. Attitude is optimized to be measured normal to gravity reference and assumes a fairly constant speed with minimal change in acceleration.

The heave measurement is used to compensate for waves in simple DGPS systems where absolute height is derived from a Tide Gauge reading. The heave measurement is internally integrated with the sounder electronics, its integration period gated by start/end of a depth reading. Typical SonarMite heave measurement sample frequency is 25Hz, this is optimized for wave periods between 2.0 and 0.2 Hz, the system is not intended for swell compensation (long term heave at 0.2 to 0.02 Hz).

SonarMite Specification
Transducer Frequency
235KHz Active Transducer
Beam Spread
6 to 10 Degrees
Depth Range
0.30m to 75.00m (Software limited)
Accuracy
+/-0.025m (RMS)
Sound Velocity Range
1400 to 1600 m/sec
Data Output Range
2Hz
Ultrasonic Ping Rate
3 to 6 Hz (Depth dependent )
Pitch/Roll sensor
usable range +/-45 degree
static resolution +/-0.2 degree
dynamic accuracy +/-1.0 degree

Heave sensor
Sensor +/- 2G
range +/- 1.0m @ 2Hz
accuracy +/-0.05m
Internal Power
12.0v x 2.0AHr Internal sealed lead/acid battery
Power Consumption
40ma to 100ma (temp dependent)
Usable Battery Life
8 Hrs to 24Hrs between charging
Stand-By Battery Life
10000 Hours
Battery Charge
Switch mode charger for 90..250vac, 40..60Hz
Work Anywhere
2/3 Round/Square pin charger adaptor
Data Output
SonarMite, simple ASCII, NMEA
Data Format
RS232C 9600 baud 8 bit 1 stop bit No parity
Operating Temperature
0 to 45 degree Centigrade
Overall Dimensions
120w x 220d x 80h (mm)
Weight
1.5Kg