Laser echo signal simulator is one of the most significant components of hardware-in-the-loop (HWIL) simulation systems for LADAR. System model and time series model of laser echo signal simulator are established. Some influential factors which could induce fixed error and random error on the simulated return signals are analyzed, and then these system insertion errors are analyzed quantitatively. Using this theoretical model, the simulation system is investigated experimentally. The results corrected by subtracting fixed error indicate that the range error of the simulated laser return signal is less than 0.25m, and the distance range that the system can simulate is from 50m to 20km.
LADAR echo signal simulator is one of the most significant components of hardware-in-the-loop (HWIL) simulation systems for LADAR, which is designed to simulate the LADAR return signal in laboratory conditions. The device can provide the laser echo signal of target and background for imaging LADAR systems to test whether it is of good performance. Some key technologies are investigated in this paper. Firstly, the 3D model of typical target is built, and transformed to the data of the target echo signal based on ranging equation and targets reflection characteristics. Then, system model and time series model of LADAR echo signal simulator are established. Some influential factors which could induce fixed delay error and random delay error on the simulated return signals are analyzed. In the simulation system, the signal propagating delay of circuits and the response time of pulsed lasers are belong to fixed delay error. The counting error of digital delay generator, the jitter of system clock and the desynchronized between trigger signal and clock signal are a part of random delay error. Furthermore, these system insertion delays are analyzed quantitatively, and the noisy data are obtained. The target echo signals are got by superimposing of the noisy data and the pure target echo signal. In order to overcome these disadvantageous factors, a method of adjusting the timing diagram of the simulation system is proposed. Finally, the simulated echo signals are processed by using a detection algorithm to complete the 3D model reconstruction of object. The simulation results reveal that the range resolution can be better than 8 cm.
LADAR guidance technology is one of the most promising precision guidance technologies. In the aim of simulating the
return waveform of the target, a 3D geometrical model of a target is built and mathematical model of target echo signal
for imaging LADAR target simulator is established by using the coordinate transformation, radar equation and ranging
equation. First, the 3D geometrical data of the object model is obtained by 3D geometrical modeling. Then, target
coordinate system and viewpoint coordinate system are created respectively. 3D geometrical model is built in the target
coordinate system. The 3D geometrical model is transformed to the viewpoint coordinate system based on the derived
relationship between the two coordinate systems. Furthermore, the range information of the target could be obtained
under viewpoint coordinate system. Thus, the data of the target echo signal can be obtained by using radar equation and
ranging equation. Finally, the echo signal can be exported through corresponding data interface. In order to validate the
method proposed in this paper, the echo signal generated by a typical target is computed and compared with the theory
solutions. The signals can be applied to drive target simulator to generate a physical target LADAR image.