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MALA MIRA Operating Manual

Imaging radar array
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MALÅ MIRA System
Operating Manual v. 1.1
19-001034

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  • Page 1 MALÅ MIRA System Operating Manual v. 1.1 19-001034...

  • Page 2: Table Of Contents

    2.1 The ProEx control unit 2.2 The MIRA option 2.3 Antennas 2.4 Positioning systems 2.5 Accessories 3 System set up 3.1 Antenna array 3.2 ProEx control unit and MIRA option 3.3 Antennas 3.4 Power 3.5 Computer 3.6 Positioning system 3.6 Remote Control 3.7 Others 4 Data acquisition 4.1 Planning the survey...

  • Page 3: Introduction

    1 Introduction ___________________________________________________________________ Thank you for purchasing the MALÅ Imaging Radar Array, the MIRA System. The MIRA system enables any combination between the individual receiver and transmitter antennas used in the array. The separate transmitter and receiver antennas can be combined into one single antenna array unit tracked and positioned by a total station or RTK GPS for precise positioning.

  • Page 4: Unpacking And Inspection

    1.3 MALÅ Geoscience Indemnity Clause Operators of MALÅ MIRA system or other GPR systems shall hold harmless, defend, and indemnify MALÅ Geoscience from and against any and all losses, liabilities, damages, injuries, claims, demands, costs and expenses or claims including claims by third parties arising out of the use or possession of the MALÅ...

  • Page 5: System Components

    Power supply for the ProEx control unit and the antenna array, 12V. These different parts are explained in more detail below. Fig. 2.1 The MIRA system, with the antenna array on a vehicle (A) and the positioning system (self- tracking Total station) (B).

  • Page 6: The Proex Control Unit

    More on this can be read in the ProEx operating manual. The ProEx main unit communicates via a fast Ethernet link with a PC. In the MIRA system the ProEx control unit will operate more or less as a slave. Its main task is to keep track of the position along the profile and collect data at equidistant points.
  • Page 7 One side of the array option has coaxial connectors for the receiver and transmitter trig lines. The number of lines is dependent on how the system was ordered. The MIRA option in Fig. 2.5 is for maximum 10 receivers and transmitters. The standard array option is equipped to handle 16 channels.

  • Page 8: Antennas

    Fig. 2.6. The MIRA option connected to the ProEx control unit. The metal plate and place for securing screws are marked. 2.3 Antennas The MIRA system is designed to handle shielded separable antennas only, no other antennas can be used with the MIRA system. The MALÅ separable antennas are designed to show as similar response (signature) as possible and each data channel in the array is tested individually with regard to this parameter.

  • Page 9: Positioning Systems

    3D radar picture correct and reliable. Centimetre accuracy is needed over the whole investigation site. The MIRA system can be positioned by using a RTK GPS system or a self-tracking laser theodolite, a so called total station. A prism or a GPS rover antenna is attached to the array box, and a radio link transfers the positioning data from the GPS base station or Total station back to the acquisition laptop.
  • Page 10 Total station: A self-tracking total station is locked on and follows a prism mounted on the antenna array when the MIRA system moves in the investigation area and a radio link communicates the data from the Total station to the MIRASoft. See Fig. 2.9. The Total station should be of ATS type.

  • Page 11: Accessories

    Total station is needed, though. 2.5 Accessories The target applications for the MIRA systems are radar surveys over large areas and, practically, it’s not feasible to move the array manually over thousands of square meters. Some kind of motorized carrying system is usually necessary.
  • Page 12 400 MHz 16 channel array. Fig. 2.12. A 12 channel MIRA 400 MHz antenna array mounted on a small cart. Whatever vehicle chosen to carrying the MIRA, some adoption for the radar system has to be done, these include: Fastening arrangement for the array box.
  • Page 13 carrier as the antenna array box has quite high power consumption. The vehicle must be able to support 12V@22Amps. In order to perform effective surveys the following tools and accessories are needed: Marking system for plotting the array paths on ground. This is necessary in order for the operator to ensure proper coverage of the area.

  • Page 14: System Set Up

    3 System set up ___________________________________________________________________ In this chapter all connections to make prior operation of the MIRA system is explained. The MIRA system is developed to be rough and stand heavy weather conditions. However, it is advisable to make all connections within the antenna box in dry conditions, to prevent water in the electrical outlets.

  • Page 15: Proex Control Unit And Mira Option

    3.2 ProEx control unit and MIRA option The ProEx control unit is mounted to the MIRA option, with the two 25-DSUB connectors, and secured by two screws on each side. See Fig. 3.4. Fig. 3.4. Connection of the ProEx unit to the MIRA option.

  • Page 16: Antennas

    Fig 3.6 The cables from the antennas are connected to the MIRA option. Observe that the connectors are marked both on the antennas and on the MIRA option, with T (Transmitter), R (Receiver) and D (Data). The T and R are found on one side and D on the other.

  • Page 17: Power

    The MIRA system operates at 10-14V and to supply the system from a car battery is most convenient. MALÅ Geoscience provides suitable cables and boxes for this. See Fig. 3.8. However it is recommended to power the system directly from the carrier used, as an ordinary car battery will last for approximately 4-5h.

  • Page 18: Computer

    The Ethernet cable is used to transfer the measured data from the control unit to the computer for storage, display and processing. Fig. 3.9 Ethernet connections for communication between the MIRA option and computer. The computer communicates...

  • Page 19: Remote Control

    The GPS needs to send out data in NMEA 0183 GGA format. However this is saved in a local coordinate system, related to the centre of the local coordinate system set in MIRA Soft. Place the GPS base antenna outside the investigation area. Note! Sometimes the distance between the base and the rover needs to be several hundred meters during initialization.
  • Page 20 The MIRA system can also be used together with a remote control for an even easier operation of the measurement system, see Figure 3.12. Instructions in eight simple steps are found below. Fig. 3.11. The MIRA remote control, with three function buttons (Stop, New and Marker) and 4 LED indicators.

  • Page 21: Others

    Connection on the ProEx (AUX1). Right: Connection on the inside of the antenna box (15-pin DSUB).. 3. Turn the power ON to the MIRA antenna box and make sure that MIRASoft is running. 4. At start, the LED´s 3 and 4 are showing a red steady light to indicate that the ProEx do not have any connection with the MIRASoft.
  • Page 22 Fig. 3.12. The encoder wheel on the carrier wheel (left) and connection of the encoder cable to the antenna box. Inside the box the encoder cable is connected to the ProEx unit. See Figure 3.13. Fig. 3.13 The wheel encoder connector on the ProEx unit. If no antenna box is used the encoder cable is connected directly to the ProEx unit.
  • Page 23 Fig. 3.15. Standard UNC thread on top of the spray marker holder. The spray can marker box is seen in Figure 3.16 below and is powers supplied from the MIRA antenna box. Spray marker box:...

  • Page 24: Data Acquisition

    Prior to radar data acquisition, thoroughly planning of the survey should be done. It’s advisable to conduct the data acquisition in straight lines, so called swaths, whenever possible. The MIRA system does not require straight swaths but the positioning errors will be less and the coverage of the area will be easier managed if the geometry is kept simple, see an example in Figure 4.1.
  • Page 25 Fig. 4.2. Example of measurement swaths and mapped objects in the surrounding for reference. So called Tie-in points are used if the Total Station position needs to be moved. More can be read in the operation manual for MIRASoft. To control the actual data acquisition, an odometer (encoder) wheel is used to achieve a precise trace interval (point distance).

  • Page 26: Data Collection

    4.2 Data collection When the MIRA system is connected as explained in Chapter 3, the system can be powered on and data acquisition can start. Note! The power cannot be turned ON before the MIRA option is securely connected to the ProEx unit.
  • Page 27 Swaths can also be remade later and included in earlier projects. However, then it is important that the swaths are marked, and can be re-found, and if working with the Total station, the same tie-in-points are used and positioned for the new swaths. As one swath is finished, the measurement is stopped according to the MIRASoft manual, the antenna array is moved back to the start position and a new swath is started.
  • Page 28 www.malags.com Corporate Headquarters Offices MALÅ Geoscience AB USA: MALÅ Geoscience USA, Inc., 465 Deanna Lane, Charleston, SC 29492 Skolgatan 11, SE-930 70 Phone: +1 843 852 5021, Fax: +1 843 284 0684, E-mail: sales.usa@malags.com Malå, Sweden Phone: +46 953 345 50 China: MALÅ...

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