Nowadays there is a task of automation of trajectory and rapid processes parameters measurements with subsequent immediate processing of measurement results, in particular, when testing the high-speed missile systems products. Measurement automation in this area contributes to significant improvements in the accuracy and speed of measurements.
Thus, ZETLAB mobile complex allows to reduce the time of obtaining trajectory measurement results from several hours to dozens of minutes. Moreover, the kit ensures visualization of many critical parameters, such as display of object trajectory and highlighting of the landing coordinates on the map.
The purpose of trajectory measurements is to determine the motion parameters of various objects: missiles, artillery shells, aircraft, including drones. The optical measuring tools integrated in the kit are often used for such measurements. Hereinafter, the various functionally complete parts of the kit will be referred to as a “segment”.
It is obvious that the object tracking by means of video alone does not allow to accurately and quickly determine the coordinates and exact time of landing with further detonation, because subsequent processing is performed by an operator. For example, if a missile is controlled, the mutual analysis of times of landing and further detonation allows to determine the missile penetration depth.
Based on the aforesaid, it becomes clear why there is a need to improve the basic methods of trajectory measurements and trajectory measurement automation for increasing the accuracy of results and data processing rate. ZETLAB has made a significant breakthrough in this area by applying a revolutionary solution that combines several fundamentally different segments into a single kit:
- segment for high-speed video recording,
- segment for high definition (HD) video recording
- segment for determining the coordinates of object landing on a ground target and the exact time of contact according to seismic recording systems.
In addition, the replacement of seismic recording system with acoustic recorders allows to handle cases with ground and air targets.
General Description of ZETLAB Trajectory Measurement Kit
For optical tracking of moving objects, this mobile trajectory measurement kit by ZETLAB applies two principles: high-speed video recording and high definition (HD) video recording. The matching and further processing of recorded video data is performed at the information collection and processing station. Recording of exact time, direction and location finding of the place of object landing or its contact with the target are performed according to readings of the seismic segment, which is based on the analysis of readings of several distributed seismic recording systems. The essence of the seismic segment operation is recording of a seismic wave, which occurs at the moment of object contact with the ground and, propagating in all directions, gradually affects various seismic sensors installed within the control area. Then the seismic recording system provides information to the data collection and processing station, which determines the exact time and coordinates with subsequent visualization on the pre-loaded map.
This kind of testing is quite complicated to implement, so the measuring process requires simultaneous integration of multiple parameters and solving many tasks, some of which are as follows:
- measuring session planning;
- recording the monitored object via high-speed and HD video recording at the moment of set target approximation;
- determining the exact time of object contact with the target (or ground) and coordinates of the place of contact;
- determining the parameters of object trajectory;
- determining the total firing-to-impact time of the object.
Technical Specifications and Arrangement of the Kit
As follows from the short list of kit objectives, the actual technical specifications of the kit are critical: the angle of device rotation in azimuth and in elevation, the recording time of high-resolution camera and high-speed camera, the root-mean-square deviation of the video frames reference to the CMEA scale, the diagonal field of view of video recording device for lens in different ranges, the root-mean-square deviation of positioning at different altitudes (including super low, 50 m and lower), the root-mean-square deviation of the geodetic reference of video recording stations to the point of object contact with the ground.
The hardware of ZETLAB mobile trajectory measurement kit consists of several shipping containers (one for each of the stations) and individually packaged masts, surveying tripods, and a free-running electric generator.
Trajectory Measurements and Kit Deployment: sequence of operations
The workflow of trajectory measurements is quite simple and implies a sequence of actions: kit deployment on site, video recording, video processing, and kit dismantlement.
The kit deployment on site is implemented efficiently and quickly in a fairly short time, and includes installation of surveillance camera station (Figure 1), high-speed video recording stations (Figure 2), high definition video recording station (Figure 3). Once recorded, the information is efficiently processed and visualized at the information collection and processing stations (Figure 4).
Figure 1 — Block diagram of camera control station
Figure 2 — Block diagram of high-speed video recording station
Figure 3 — Block diagram of HD video recording station
Figure 4 — Block diagram of information collection and processing station
The video recording stage includes remote engagement of station and remote recording completion by the operator or automatically upon signal receipt from a seismic station (Figure 5).
Figure 5. Typical layout of video recording stations via mobile trajectory measurement kit
The stage of video records processing and kit dismantlement:
- determining the exact time of object contact with the target (or ground);
- transferring the information from video recording stations to a PC for data processing;
- building the two- and three-dimensional trajectories;
- position finding of the place of the object contact with the ground according to readings of seismic recording systems, as well as visualizing the measurement results (Figure 6). Figure 7 shows typical flowchart of data collection and processing from seismic sensors in ZETView software of mobile trajectory measurement kit;
- kit dismantlement by visiting station locations and packing the equipment into the corresponding containers (which usually takes hours) is easily completed due to compact hardware dimensions.
Figure 6. Visualization of seismic impact source position finding results according to the method of inverse correlation functions
Figure 7. Typical flowchart of direction finding based on four seismic sensors in ZETView software of mobile trajectory measurement kit. A three-component seismic sensor is shown on the left
The advantages of the kit include automation of measurements, rapid information acquisition for analysis, and measurement results visualization in a convenient form for the operator. Application of the kit significantly reduces labor and financial costs and improves the quality of measurements, which is achieved by using the minimum amount of hardware based on the ZETLab commercially manufactured products.
The kit composition is described in section Seismic Station and Seismic Receivers ⇒ Use Cases ⇒ Mobile Trajectory Measurement Kit.