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Airborne vector geomagnetic measurement can not only obtain total geomagnetic field strength of geomagnetic field, but also detect the vector information of geomagnetic field, so it is an effective technology to obtain the geomagnetic field information of land and offing area in high precision and resolution quickly. Therefore, this technology has broad application prospect in the domain of aviation, sailing, and spaceflight, especially in the application of self-navigation of geomagnetic matching. The first airborne vector geomagnetic measurement was successfully developed by Xi’an research institute of surveying and mapping and national space science center of Chinese academy of sciences in China. During May-June in 2015, and June-July in 2016, the integration experimentation of the airborne vector geomagnetic measurement was organized by Xi’an Research Institute of Surveying and Mapping on the plain of Inner Mongolia, it included 227 flying surveying lines, and of which the length was about 5000 kilometers, so a great amount of total geomagnetic field strength and vector information of geomagnetic field were obtained. Based on 15 repeated flying surveying lines, 400 crossing points of 20 intersection flying surveying lines in the direction of south-north, east-west, which are in 200m and 700m flying height, the precision evaluation of the airborne vector geomagnetic measurement is accomplished by the comparison of repeated flying surveying lines and crossing points. From the comparison of repeated flying surveying lines, we can get the conclusion that the precision of total geomagnetic field strength on the flying surveying lines in 200m and 700m flying height are 2nT and 1nT, respectively. The precision of three components of the geomagnetic field are between 5nT and 10nT. And from the comparison of crossing points, we can get the conclusion that the precision of total geomagnetic field strength on the flying surveying lines are 1nT, the precision of three components of the geomagnetic field are below 10nT. Therefore, from the data processing of the first airborne vector geomagnetic measurement in China, we can see that the precision of total geomagnetic field strength is about 2nT, and the precision of three components of the geomagnetic field are about 10nT.

The concepts of cooperative diversity promise to offer the benefits of spatial diversity gains to handheld wireless devices with single antennas. So far the research has focused on the situation where perfect channel state information is available and coherent detection is employed at the destination receiver. This paper proposes a differential super-orthogonal space-time trellis code modulation scheme for a two-user cooperative diversity system, which does not require channel state information at either users or destination while providing a performance about 1. 5 dB better than DSTBC and 3 dB worse than the corresponding coherent scheme.