From Al DeLorey, lowflying.com, 482-8094
To: Scott Smith, Ventura County Director of Airport
Subject: Low Flying Aircraft Monitoring System Verification & Validation
Ref: A: lowflying.com

The low flying aircraft monitoring system that I am proposing for the Ventura County Airports to use is the same as the system that I'm currently using except for the specific type of camcorder (see Ref A, Build It Yourself). There are two reasons why I would want to change the camcorder. Firstly, the current camcorder is not weather proof. Secondly, the current camcorder has a zoom lens. A fixed lens would be more reliable because its magnification could not be changed accidentally. This doesn't mean we shouldn't verify the current system. The verification system that we would use for the current system would be the same as the verification for the final system. The current camcorders could be used until they are replaced. I've outline some discussion point below about the system's verification procedure.

1. Who would be the Ventura county person who signs off on the acceptance of the verification & validation procedures of the system? This acceptance means that if all the defined tasks are successfully done then the system works. This process has many passes through it to allow the acceptance person to review the testing process.

2. There are three inputs to the monitoring system that are used to determine the altitude of an aircraft. They are the monitoring sites location, the monitoring sites altitude, and the elevation angle from the sites to the aircraft.

Two of the three inputs are the location and altitude (MSL) of the observation sites. These two inputs are from accepted industry standards. We have the United States Geological Survey quadrangle maps and the County Bureau of Horizontal measurements for these two inputs. This leaves the third input of using the camcorder to measure the elevation angle to the aircraft to be verified & validated.

Using an optic lens to measure angles has been around for a long time. The lens makers control how the optic lens distorts the angle measurements. The effects of the angle distortions are well documented by the lens maker. The only verification & validation question now is how well does the camcorder measure the elevation angle. I'm proposing to test the camcorder angle measuring ability like you would test a sextant. I've run these test already (see Ref A, charts of sun vs. camcorder angle measurements). The videotapes of these tests are available for review. I could set up and run more series of tests if someone would want to run their own independent set of tests.

3. There are many ways to do a verification & validation procedure for a system. I propose that I write up a set of verification & validation test procedures. The procedure will have a series of tasks to be tested. Each test has a defined criteria for each specific task for it to pass. If all the tasks are done successfully then it would mean the system will work correctly. The verification & validation procedures would be written in a "cook book" manner. This "cook book" method allows a person who knows nothing about the system to make an independent verification of the test results.

Respectfully,

Al DeLorey