A LOOK BACK IN
TIME... THE BIRTH OF CODAR AT NOAA
12 January, 2010
first HF radar to demonstrate and validate current and wave measurement
capability was built between 1969-1973 in a program led by DARPA
and NOAA, in cooperation with Scripps Institution of Oceanography
and Stanford University. Designed by Donald Barrick at NOAA Environmental
Research Laboratories (ERL), the radar with its conventional 500-meter
long phased-array antenna was bulky and inconvenient for deployment,
but proved the point that HF radar is a viable tool for measurement
of ocean current and wave parameters.
After the initial success, NOAA's ERL commissioned Dr. Barrick in 1972 to develop
a practical replacement for the large and expensive phased array antenna design.
The technology resulting from this NOAA program was called CODAR, an acronym
standing for Coastal Ocean Dynamics Applications Radar.
In 1977 the prestigious journal Science published an article on the demonstrated
CODAR success. Shortly after, in 1978 the NOAA team that developed CODAR was
awarded the U.S. Department of Commerce Gold Medal Award. Various patents relating
to the technology were granted within the NOAA group starting in 1979.
In the early 1980s, the core team that invented the original CODAR was encouraged
by NOAA to move into private industry, to continue the technology evolution and
provide a commercial source for institutions to acquire HF radar equipment. That
company became CODAR Ocean Sensors, Ltd. The technology has evolved from original
CODAR radar and is now the SeaSonde®. It remains the only commercially
available HF radar system that is based on the groundbreaking compact HF radar
concept developed and patented inside NOAA, while all other HF radars still utilize
the phased array approach that was abandoned back in the 1970s. As of 2010, the
SeaSonde represents over 85% of all HF radars ever built and used for ocean current
and wave measurements, with systems used in 22 countries.
Photos illustrate the current mapping HF radar antenna
evolution. Starting with image #1: 500-m long
phased array radar at San Clemente Island, circa 1972.
Smaller inset image shows the trailers
used to house the radar electronics and computer system.
Image #2: the first
NOAA-built CODAR antenna system consisting of a square
monopole receive array with
direction-finding closed-form solutions for bearing. Smaller
inset image shows the electronics
and DEC PDP-11/23 computer and tape drives used for near-real-time
processing and archival.
Image #3: The first crossed-loop CODAR antenna,
built of copper. Image #4: a later version of crossed-loop
CODAR antenna, built of PVC. Image #5: Successor to CODAR,
the SeaSonde. Image #6: Latest SeaSonde antenna
system with all transmit and receive elements colocated
atop a single mast. The unit shown is
located on Scripps Pier in La Jolla, California. Image
#7 shows latest SeaSonde electronics system, consisting
of a small but powerful mini-processor
and two 19” electronics chassis.