Due to some significant advantages such as high space resolution, three-dimensional imagery (including intensity image
and range image) acquiring, and so on, an imaging laser radar is helpful to improve the correct recognition ratio being as
a sensor in a target recognition system. A chirped amplitude modulation imaging ladar is based on the frequency
modulation/continuous wave (FM/cw) technique. The target range is calculated by measuring the frequency difference
between projected and returned laser signal. The design of a signal processing system for a FM/cw imaging ladar is
introduced in this paper, which includes an acquiring block, a memory block, a communication block, and a FFT
processor. The performance of this system is analyzed in detail in this paper.
The accumulation of space debris is expected to present an increasing threat to orbital aerostat. To develop and use
space resource continually and in security the detecting technology for space debris has to be improved.
The paper firstly introduces the concept of space debris and their common detection means, and then introduces the
application of lidar in detecting the space debris. Comparing with conventional optical observation systems lidar adopts
active detecting mode, without the limitation of illumination and with a long detecting distance. It also can measure
range and speed of targets. Comparing with microwave radar the beam of lidar is narrow and it has great orientation
precision and resolving power.
To satisfy detecting small-sized debris in long distance and big area the paper proposes the composite method to
detect the space debris which uses millimeter wave radar and optic equipment. It firstly uses millimeter wave with long
distance and big view field to confirm the position of debris in long distance. And then it uses optical system with high
resolving and anti-jamming power for accurate orientation and identification. It also measure the distance, angle and
speed exactly of debris. The study in theory indicates this composite method can complete the detecting and orientation
and achieve the distance, angle and speed of the space debris more than 10cm range beyond 150km.
When laser ranger is transported or used in field operations, the transmitting axis, receiving axis and aiming axis
may be not parallel. The nonparallelism of the three-light-axis will affect the range-measuring ability or make laser
ranger not be operated exactly. So testing and adjusting the three-light-axis parallelity in the production and maintenance
of laser ranger is important to ensure using laser ranger reliably. The paper proposes a new measurement method using
digital image processing based on the comparison of some common measurement methods for the three-light-axis
It uses large aperture off-axis paraboloid reflector to get the images of laser spot and white light cross line, and then
process the images on LabVIEW platform. The center of white light cross line can be achieved by the matching
arithmetic in LABVIEW DLL. And the center of laser spot can be achieved by gradation transformation, binarization
and area filter in turn. The software system can set CCD, detect the off-axis paraboloid reflector, measure the parallelity
of transmitting axis and aiming axis and control the attenuation device. The hardware system selects SAA7111A, a
programmable vedio decoding chip, to perform A/D conversion. FIFO (first-in first-out) is selected as buffer.USB bus is
used to transmit data to PC.
The three-light-axis parallelity can be achieved according to the position bias between them. The device based on
this method has been already used. The application proves this method has high precision, speediness and
For device analysis and optimization, a model based on Transfer Matrices Method was built to simulation the
performance of a new integrated device. This novel DFB laser was composed of two serial sections to provide selectable
wavelengths. The periods of two Bragg gratings were different and were chosen to achieve a spacing of 20nm between
the two corresponding Bragg wavelengths. The model is more simple and convenient to simulate optical integrated
device than other direct simulation methods used before. The simulation results prove that this novel waveguide structure
of the serial DFB lasers is feasible. The integrated optical device was fabricated and two wavelengths of 1.51um and
1.53um were realized under different work conditions.