What is aerial remote sensing technology?

Aerial remote sensing (aerial remote sensing; Aerial remote sensing, also known as airborne remote sensing, refers to the remote sensing technology carried out in the air by using various planes, airships and balloons as sensor carriers. It is a multifunctional comprehensive detection technology developed from aerial reconnaissance. According to the working altitude and application purpose of the aircraft, it can be divided into high altitude (10000m-20000m), hollow (5000m- 10000m) and low altitude (

Aircraft is the main platform of aerial remote sensing, which has the characteristics of high resolution, short investigation period, no limitation of ground conditions and convenient data recovery. High-altitude balloon or airship remote sensing has the characteristics of high flying height, large coverage, long stay time in the air, low cost and simple flight control. At the same time, it can also carry out remote sensing activities in the stratosphere that is difficult for planes and satellites to reach.

In addition to traditional aerial photography, remote sensing methods include multi-band photography, color infrared and infrared photography, multi-band scanning and infrared scanning, side-looking radar and other imaging remote sensing; It can also be used for non-imaging remote sensing such as laser altimetry, microwave detection and spectral testing of ground objects. Most of the sensors used in aerial remote sensing are aerial cameras, aerial multispectral scanners and aerial side-looking radars. The image data obtained by aerial camera are all kinds of aerial photos (such as black and white film, black and white infrared film, color film, color infrared film, etc.). ). Multispectral scanners can obtain multispectral aerial photographs, with much more information than single-band aerial photographs. Airborne side-looking radar emits microwaves from the side of the plane. After encountering the target, the backscattered return pulse is scanned and imaged on the display, and recorded on the film to generate a radar image.

With mature aerial remote sensing technology, large imaging scale and high ground resolution, it is suitable for large-scale topographic mapping and small-scale detailed investigation without complex ground processing equipment. The disadvantages are poor flying altitude, endurance, attitude control, all-weather operation ability and large-scale dynamic monitoring ability. However, as a means to explore and study the earth's resources and environment, it is still in the ascendant and irreplaceable.

Space remote sensing; ; Spaceborne remote sensing)

Definition:

In the outer space of the earth's atmosphere, remote sensing is based on satellites, spacecraft, space shuttles, rockets and other spacecraft. Synonym: space remote sensing

The technology of collecting electromagnetic waves radiated or reflected by ground objects by using remote sensors installed on spacecraft to obtain and identify atmospheric, terrestrial or marine environmental information. Various ground objects have different electromagnetic wave radiation or reflection characteristics due to different types and environmental conditions. An instrument that senses and collects electromagnetic waves radiated or reflected by ground objects and environment is called a remote sensor. Space remote sensing can provide a variety of rich information about ground objects or the earth's environment, and has been widely used in many aspects of national economy and military affairs, such as meteorological observation, resource investigation, map mapping and military reconnaissance. Space remote sensing is a comprehensive science and technology, which includes studying the electromagnetic spectrum characteristics of various ground objects, developing various remote sensors, and studying the recording, transmission, reception, processing methods, analysis, interpretation and application technologies of remote sensing information. The core content of space remote sensing is the acquisition, storage, transmission and processing technology of remote sensing information.

The carrier of remote sensing refers to the remote sensing platform. Remote sensing platform is divided into:

Ground platform: calibration and auxiliary work of aviation and space remote sensing.

Aviation platform: a platform below 80 kilometers, including airplanes and balloons.

Space platform: a platform more than 80 kilometers, including high-altitude exploration rockets, artificial earth satellites, spacecraft and space shuttles.

It can be seen that the main differences between space remote sensing and aerial remote sensing are: first, the remote sensing platforms used are different, and space remote sensing uses space vehicles, while aerial remote sensing uses air vehicles, which is the most important difference; Second, the height of remote sensing is different. The altitude of polar-orbiting satellites used in space remote sensing is generally around 1000km, and the altitude of stationary meteorological satellites is around 360O km, while the flying altitude of aircraft used in aerial remote sensing is only a few hundred meters, several kilometers and dozens of kilometers. As the saying goes, you can only see far if you climb high. Compared with aerial remote sensing, the sensing area of space remote sensing is obviously much larger. A multispectral image of Landsat covers an area of 34,000 square kilometers, which is equivalent to the island of Taiwan Province Province, while meteorological satellites over the equator can cover an area of 40 north-south latitude and 70 east-west longitude. Therefore, space remote sensing can always monitor the earth with an unprecedented broad field of vision.