Motors and Automatic Target Recognition

Motors... l Motorized Instruments have 2 Motors: –One to Rotate the Alidade Horizontally –A Second to Rotate the Telescope Vertically l The Motors may be controlled by: –The User –The Operating System –On-Board Programs

Motors... l Motorized Instruments Do Not have Tangent Locks l The Tangent Drives are 2 Speed Electronic Switches l It’s OK to Rotate the Alidade or Telescope Manually l Motor Resolution is 2 Seconds

Motors Alone... l Speed up the Process of Rotating the Alidade or Telescope

But Motors with ATR... l Enables Automatic Angle and Distance Measurement to the Target without the User Accurately Sighting the Prism l Enables The Instrument to “Lock On” and “Follow” a Moving Target

Motors with ATR... l Enables Remote Controlled Surveying l Makes “Real Time” Mapping Much More Efficient

How ATR Works - Page 1 l A Laser Beam is Transmitted Coaxially Through the Telescope l The Beam is Reflected by the Prism and Returned to the Theodolite l The Received Beam is Recognized by an On-Board Camera (CCD Grid)

How ATR Works - Page 2 l The Position of the Received Light Spot (with respect to the center of the CCD Grid) is Computed. l The Computed Horizontal and Vertical Offsets are used to Control the Motors to Turn the Instrument to Center the Crosshairs on the Prism

How ATR Works - Page 3 l The Instrument Sights the Prism Center Coarser than the Specified Angular Accuracy l The ATR System Measures the Offsets Between the Crosshair and Prism Center l The Horizontal and Vertical Angles are Corrected and Displayed To Optimize Measuring Times:

How ATR Works - Page 4 l The Horizontal and Vertical Angles are Measured to the Prism Center, Regardless of the Crosshair Pointing l Caution: Determination of the ATR Collimation Error Must be Carried Out Periodically

How ATR Works - Page 5 l The Sensitive Area of the ATR is Centered and about One-Third of the Field of View l The Prism is Recognized Instantly within this Sensitive Area l If the Prism is Outside the Sensitive Area, the Field of View is Scanned Spirally Searching for the Prism The Search for the Target:

Warning! Although the Invisible ATR Laser Beam is a Class 1 Laser Product and is harmless under Normal Conditions... It can be Dangerous to look into the beam with Optical Equipment (binoculars, telescopes, etc)

ATR Specifications - Page 1 Pointing Accuracy

ATR Specifications - Page 2 Range

ATR Specifications - Page 3 Rotation and Speed

ATR Operation - ATR Mode l Press the Fixed Key l Press (ATR) l This Switches ATR “ON” and Returns to the Previous Dialog l Sight the Prism Coarsely l Activate a Distance Measurement

ATR Operation - ATR Mode l If the Prism is outside the Sensitive Area, the Field of View is Scanned Spirally l If a Prism is Not Found, an Error Message is Displayed l If the Operator Retries the Search, the Scanning Area is increased by 1/3 l If the Prism is Found, the Distance is Measured

ATR Operation - Lock Mode l Lock Mode Will Enable the TCA to Follow a Moving Target l Press the Fixed Key l Press (Lock) l The TCA Switches to ATR w/Lock “ON” and Returns to the Previous Dialog l Switching to “Lock” Requires an Initial Distance so that ATR “learns” the Prism

ATR Operation - Lock Mode l Sight the Target Coarsely l Activate a Distance Measurement l If the Prism is Found, the TCA will “Lock On” and Follow the Target

ATR Resolution Modes l ATR Resolution is Defined as the Accuracy of the Center of Prism Determined by ATR l Selecting Different Resolution Settings allows the User to Optimize Acquisition Speed for Various Accuracy Requirements l The More “Inaccurate” that the ATR is Set, the Faster the Measurement

ATR Resolution Modes l The Resolution May be Set with Various Distance Measuring Modes l Press the Fixed Key l Press (EDM Measuring Program) to Select an Appropriate ATR Resolution as Shown in the Following Table

ATR Resolution Modes

ATR Problems and Countermeasures l Reduced Range –Causes l Hot Sunny Weather l Strong Heat Shimmer l Bright Reflections –Counter-Measures l Reduce Measurement Distance l Measure Without ATR

ATR Problems and Countermeasures l “No Prism Found or Bad Conditions” –Causes: l No Prism in Field of View l Strong Heat Shimmer l Measurement Distance too Great l Too Bright –Countermeasures: l Reduce Distance l Cover Reflections l Measure without ATR

ATR Problems and Countermeasures l “Multiple Prisms Found” –Causes: l Several Prisms in Field of View l Raindrops on Prism or Objective Lens of Telescope –Countermeasures: l Ensure that only one Prism is in Field of View l Remove Raindrops

ATR Problems and Countermeasures l “Position Not Achieved or Prism Unstable –Cause: l Oscillation of Prism at short distances –Countermeasure: l Measure without ATR

ATR Problems and Countermeasures l Disturbance of Target Tracking in “Lock” –Causes: l Measurement Distance too Great l Bright reflection close to Prism (TCA tracks reflection) l Strong Heat Shimmer (TCA trembles or turns away from Prism) –Countermeasure: l Reduce Measurement Distance l Target Prism Manually and Restart “Lock”

ATR Problems and Countermeasures l TCA Suddenly Switches Off –Cause: l There are Very High Current-Consumption Peaks When the Motors are Starting Up and When the EDM is Being Switched on –Countermeasure: l Change the Battery