To expand their search range, unmanned aerial vehicles (UAVs) used for surveillance employ satellites as relays to forward monitoring data to the UAV's command and control centers. With updated sensors, the amount of UAV detection data increases sharply, and the demand for bandwidth and transmission rates increase continuously. In this paper, the Ka-band is introduced to the satellite system as a solution instead of the Ku, C and other bands. Highly robust constant coded modulations (CCMs), such as the binary low-density parity-check (LDPC) and the coded quadrature phase shift keying (QPSK) are adopted to handle poor channel conditions caused by rain attenuation, which lead to a waste of spectral efficiency, especially in poor weather conditions; Adaptive Coded Modulation (ACM) can relieve the problems detailed above. Aiming at the problem mentioned above, we have proposed two different transmission schemes for two typical scenarios, including high quality of service (QoS) and high throughput service. The first is the so called automatic repeat request (ARQ)+ACM (target bit error rate (BER) algorithm) for high QoS, which means ARQ and ACM are employed by UAV-satellite links and satellite-center links, respectively. The second, denoted as coded cooperation (CC)+ACM (the maximum throughput algorithm) for high throughput services, designates that CC is employed for UAV-satellite links and ACM is employed for satellite-center links. Simulation results show that the ARQ+ACM scheme achieves higher spectral efficiency than CCM in cases that keep the BER below 5 10 − , and the CC+ACM scheme attains 3 to 7.5 times the spectral efficiency of CCM.

Employing multiple UAVs as a swarm for investigation and surveillance can complete more complex missions. Since novel sensors equipped, vast amounts of data are continually generated as the increasing number of UAVs. Therefore, the process of multi-source data and the valuable information from the multi-source data is of significant importance. These data formats vary from traditional data to dynamic data with the characteristic of multi-source. Considering that vast amounts of multi-source data from UAV swarm require higher throughput performance of transmission schemes, complex field network coding (CFNC) is selected for UAV cooperative system. However, adverse effects like inter-user interference of fading channels will limit the reliability performance of UAV cooperative system. To improve the reliability performance and recover more accurate valuable information, we propose a precoding-based CFNC strategy for multi-source UAV cooperative system. The proposed transmission scheme processes data through precoding matrix, which is obtained by the transformation of channel state matrix. Compared to conventional CFNC schemes, precoding-based CFNC scheme improves the accuracy of detections. Through theoretical analysis and experimental results, the precoding-based CFNC transmission scheme not only maintains high throughput, but also recover more valuable information and achieves better reliability performance.

Relay-based UAV swarm can further expand the surveillance range for more complex missions. Microsatellite swarms provide invulnerability and stability compared to conventional satellites and are selected for multi-UAVs multi-satellites systems. Determining how to recover more valuable information from the multi-source data is of significant importance. Considering that vast amounts of multi-source data from UAV swarm require higher throughput performance of transmission schemes, complex field network coding (CFNC) is selected for UAV cooperative system. However, adverse effects like inter-user interference of fading channels will limit the reliability performance of UAV cooperative system. To improve the reliability performance and recover more accurate valuable information, we propose a precoding-based CFNC strategy for multi-source UAV cooperative system. The proposed transmission scheme processes data through precoding matrix, which is obtained by the transformation of channel state matrix. Compared to conventional CFNC schemes, precoding-based CFNC scheme improves the accuracy of detections. Through theoretical analysis and experimental results, the precoding-based CFNC transmission scheme not only maintains high throughput, but also recover more valuable information and achieves better reliability performance.

Unmanned aerial vehicles (UAVs) confront various interference in the process of missions, and frequency hopping (FH) technology is one of the effective means of anti-interference for UAV. The FH system can avoid interference frequency points and possess certain anti-interference ability by making the carrier frequency continuously popping. However, the increasingly complex electromagnetic environment of UAV swarms requires more efficient anti-interference measure. To further improve the anti-interference ability of UAVs, this paper proposes a cognitive-based high robustness FH strategy. By adding a cognitive module to FH system, UAVs can avoid the interference frequency points adaptively and sensitively. The proposed system can identify typical suppressed interference and filter the interference frequency points. Cognitive FH system can avoid interference points completely with accurate detections and enhance the robustness for UAV swarms in complex electromagnetic environment compared to conventional FH system. Simulation results have shown that BER performance of proposed cognitive FH strategy is better than conventional FH strategy for typical suppressed interference.