## 1 Introduction  
Aerospace engineering is expanding rapidly. The requirements of tracking telemetering and command (TT&C) and communication in a distributed spacecraft network, however, are facing increasingly demanding challenges. A growing number of spacecraft and space missions, such as gravity mapping, remote sensing image transmitting, and water resource location, result in a heavy load in space networks. For traditional TT&C and communication (TT&CC) networks, using single large spacecraft will confront the circumstance in which a breakdown of certain parts causes the failure of the whole system. As the single large spacecraft is limited by volume, mass, power constraints, reconfiguration ability, and flexibility, different small satellites are used to undertake multicomponent space assignments, and can work cooperatively as a system or network, thus requiring inter-satellite communication (ISC) and inter-satellite ranging (ISR) [1; 2]. ISC refers to information transmission and message exchange among spacecrafts and ISR refers to measuring and evaluating relative distances among spacecrafts in a network [3; 4; 5; 6; 7]. The use of small satellite formation flying rather than individual large-scale spacecraft is the future trend in the field of TT&CC networks. Typical TT&CC networks in the area of small satellite formation flying include NASA's Space Communication and Navigation (SCAN), Planet Labs flock constellation [8], and the Global Educational Network for Satellite Operations (GENSO: The GENSO project is not operational at present.) in the European Space Agency (ESA). Furthermore, SCaN is composed of the Near Earth Network (NEN), Space Network (SN), and Deep Space Network (DSN), and is an integrated and complete TT&CC network [9]. The requirements of inter-node communication (INC) and inter-satellite ranging (INR) not only appear in distributed spacecraft networking but also remain a challenging issue in unmanned aerial vehicle (UAV) swarms and other self-organized networks. Furthermore, to reduce hardware complexity and save the transmitting power or spectrum, an increasing number of researchers are paying attention to the design of the integrated communication-positioning networks. These methods can be classified into two groups: (i) merging communication functions into positioning or navigation systems [10; 11], and (ii) integrating positioning functions into communication systems [12; 13], especially in terrestrial wireless communication systems. For the first category, the integrated communication-positioning systems are motivated by the need for location reporting in navigation systems. The BeiDou Navigation Satellite System (BDS) is an obvious example of this issue, and can provide high-precision positioning, short message telecommunication, and a timing service. To obtain a high data rate, more exploitations of other integrated methods must be undertaken. In the data link layer, it is recommended by the Consultative Committee for Space Data Systems (CCSDS) standards that communication packets and positioning packets are transmitted alternatively, however, the ranging error will be risen when the access delay is unstable. Thus, it is not suitable for high-precision ranging. In the physical layer, surveys such as that conducted by [PERSON] showed that Gaussian filtered minimum shift keying plus pseudo-random noise code (GMSK+PN) is a bandwidth-efficient modulation to realize the integration of communication and ranging [10]. A relatively narrow bandwidth, faster secondary lobe attenuation rate, and a constant envelope characteristic facilitate the popularization of GMSK modulation under the circumstances of deep space exploration [14]. However, this method of demodulating the composite signal with GMSK+PN is intricate in computation and hardware realization, and is more suitable for deep space exploration. Therefore, unbalanced quadrature phase shift keying (UQPSK) is another feasible scheme to integrate communication and ranging.