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Test with no connections - instrumentation

I am working as a flight test instrumentation engineer with ASELSAN A.S. which is the leading defence company in Turkey. Our ongoing projects include electronic warfare installations on various rotary wing platforms and performing safety of flight tests.

I wanted to share my experience and get other expert opinions about a new instrumentation technique. During safety of flight tests, we aim to collect as much data as we can including: vibration, strain-gage measurements and also flight information such as (air speed, altitude, fuel quantity, torque etc.)

My discussion is about the second part: the collection of flight information. Today the very common technique used by many instrumentation engineers for collecting this valuable information is called \'Tapping\'. Tapping is connecting your test instrumentation between the platform sensor and the cockpit instruments. For example: you want to measure the fuel quantity during the test, so you connect one of the channels of the analog-digital converter from the data recorder to the input signals of the fuel quantity indicator on the cockpit, or to the test output of the indicator, if you are lucky, because unfortunately many indicators do not have test outputs.

The problems with Tapping is firstly the risk; i.e. connecting any cables to the platform cables may result in many risks such as distortion, unwanted short circuits. Secondly, it requires lots of cabling and a flight data recorder with analog sampling capability.

To reduce these risks we tried to develop a new method for collecting information from the cockpit indicators which we call \'Image Processing Based Data Acquisition\'. This technique is based on imaging these indicators and after that, getting the values indicated on the indicators with an image processing software. A cockpit usually contains a circle or bar graph-type indicators, so they can be easily recognized by image processing algorithms.
 
The advantages include: No contact with the platorm cabling, low cost, easy installation and no need to know the signal characteristics of the indicators.

The disadvantages include: the vibration, of  course and it is not entirely suitable for fast signals.

We are using this technique during these tests and got quite satisfying results upto now and we plan to improve the system. I want to hear the opinions of people in instrumentation business for this technique, or wonder if there is any data recorder with this capability on the market.
 

 

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