Views: 21 Author: Site Editor Publish Time: 2019-07-10 Origin: Site
While NLOS robot video transmitter has been a popular product of interest to drone enthusiasts for some time, it is difficult to fully master its features, and its many uses are unknown. If you feel that you are going to have the full use of your NLOS robot video transmitter, then read this article.
Here is the content list:
1. Definition of NLOS Robot Video Transmitter
2. Working Principle of NLOS Robot Video Transmitter
3. Characteristics of NLOS Robot Video Transmitter
If the condition that there are no objects blocking radio waves in the first Fresnel region is not satisfied, we can get the drone video transmission system, which the signal strength will obviously decline. The size of the Fresnel region depends on the frequency of radio waves and the distance between transceivers within drone video transmission system.
There are direct and reflected waves in the transmission path from long-range wireless video transmitter to receiver, and the reflected wave's electric field direction is exactly opposite to the original, with a phase difference of 180 degrees. If the air wire height is low and the distance is long, the direct wave path and reflected wave path of long-range wireless video transmitter have little distinctions, and the reflected wave will have a destructive effect. In the actual drone video transmission system, the first Fresnel region is defined as an ellipsoid containing some reflection points where the path distinctions between reflected waves and direct waves is less than half a wavelength. The most direct explanation of NLOS Robot video transmission system is that the two points of communication are blocked from seeing each other and the Fresnel area is blocked for a range of wireless video transmitter solutions more than 50%.
In order to solve the problems in NLOS wireless video transmitter solutions, we can adopt the following main technologies:
1. OFDM modulation
In mobile drone video transmission system, the time delay spread caused by multipath transmit in urban areas is roughly a few microseconds to tens of microseconds, which will bring inter-symbol interference and deteriorate drone video transmission system performance. In recent years, some people have studied the mobile drone video transmission system using multi-carrier and 16QAM modulation. Combining OFDM technology with wireless UAV transmitter solutions and channel coding technology can effectively interference, which has become the research direction of anti-fading technology in COFDM UAV video and data links.
2. Diversity technique
Diversity technology can transform multipath signal and reflected signal in NLOS Robot transmission system into treasure. Space-time coding is the combination of spatial transmission signal and time transmission signal, which is essentially a method combining spatial and time two-dimensional processing. Air wire diversity is adopted in space to improve the capacity and information rate of the NLOS Robot transmission. In time, different signals are transmitted by the same air wire in different time slots, so that the receiving terminal can receive them variously. In this way, the NLOS Robot transmission gains extra diversity and coding gain, which reduces the anti-fading reserve of the NLOS Robot transmission and improves the capacity.
3. Adaptive modulation
The technique of dynamically AMC and FEC according to the results of channel prediction is called adaptive modulation. Compared with the traditional technology that provides the same modulation order for all users, AMC technology NLOS Robot transmission can obtain higher bandwidth efficiency and NLOS Robot transmission system capacity.
COFDM UAV video link’s length is more than 2 km, can reach 20-1000 meters of horizontal wall, depending on the actual environment.
The video transmitter of 2 km long NLOS robot video transmitter adopts advanced microwave radio transmission technology, which can wireless transmit video and audio signals with high fidelity. It has the following characteristics:
The wireless video transmitter adopts high frequency microwave transmission method, video signal the carrier frequency up to three hundred MHZ to 2 GHZ, so can effectively avoid the nine hundred MHZ band crowded wireless phone signal interference, at the same time also drastically avoids the wireless video transmitter frequency of the interference of other receiving equipment. To ensure the clarity of sound and image receiving, machine wireless video transmitter is also equipped with multiple ways to choose from.
2. Video reception quality
In order to improve the reception quality of video, this wireless video transmitter adopts the excellent FM mode.
3. Application space
It overcomes the troubles brought by multipath reflection and occlusion under the simulation technology and conventional modulation technology, and realizes the wireless video transmitter transmission of two-way data, video and audio in the drone video transmission system, especially suitable for the use of complex environment.
NLOS robot video transmitters with different frequencies and wavelengths have different properties, however, we cannot deny that NLOS robot video transmitter has brought great convenience to our life. With the advancement of technology, NLOS robot video transmitter's technical progress will be more and more rapid, if you want to join this trend, welcome to consult u