FH-BOC: generalized low-ambiguity anti-interference spread spectrum modulation based on frequency-hopping binary offset carrier

Abstract

Objective The paper aims to present a generalized modulation scheme that can improve the anti-interference performance of global navigation satellite systems (GNSS) and mitigate the ambiguity problem in BOC modulation. Summary background data With the exponential growth of location-based services, there is a need to improve the positioning accuracy and the capability to resist against external interference in challenging environments, such as urban canyons, forested terrains, and indoor areas, in which signal attenuation, interference, and multipath fading can seriously degrade the positioning accuracy of global navigation satellite systems (GNSS) and GNSS-like systems. The binary offset carrier (BOC) modulation has been adopted in GNSSs because of its good spectral isolation from heritage signals, high accuracy, multipath interference resistance, and flexibility in signal implementation compared with BPSK-R modulation. However, for highorder BOC modulation, the main drawback is the ambiguity in tracking due to the multiple side peaks of the autocorrelation function (ACF). The receiver may incorrectly lock onto one of these side peaks, causing intolerable measurement bias, and this undesirable behavior limits the application of this modulation scheme in navigation systems. Methods We present a generalized low-ambiguity anti-interference spread spectrum modulation based on frequency-hopping BOC (FH-BOC). First, we formulate the mathematical model of FH-BOC modulation and derive the analytical expressions for the normalized ACF and PSD, and we analyze the time and frequency properties of several representative FH-BOC signals. Next, we present recommended parameter selections, a generation and detection scheme for FH-BOC modulation. Finally, we analyze the characteristics of the ACF and PSD, the tracking performance, the spectral separation, and the antinarrowband interference and multipath interference performance for several specific BOC and FH-BOC signals. Results The results show that FH-BOC with the largest frequency-hopping band has lower ACF ambiguity, better antiinterception performance, and better anti-intrasystem interference, narrowband interference, and multipath interference performance than BOC modulation with the same main lobe bandwidth (MLB). The tracking and anti-interference performance of FH-BOC is similar to that of BOC modulation with the same ACF main peak width. Conclusions FH-BOC is a generalized type of modulation that includes BOC modulation. The proposed FH-BOC signal improves the anti-interference performance and mitigates the ACF ambiguity problem of BOC modulation. The acquisition time and complexity of the receiving process for the proposed FH-BOC signal are the same for the BOC signal with the same MLB. The new modulation scheme which we proposed can serve as a new paradigm for the next-generation GNSS signal design, especially military signal design. It can also be used in the signal design for GNSS-like systems, such as systems for indoor positioning, GNSS enhancement, and pseudoli...

Interferometer direction‐finding system with time‐division multiplexing of spread spectrum signals

“…Therefore, the system adopts the stagger baseline method to solve integer ambiguity. 8 The integer ambiguities of the two baselines are…”

“…Thus, the system uses a spread spectrum receiving system. 9,10 Regardless of the influence of data bits, the transmitted signal is as shown in (8).…”

“…For high‐frequency signals, the integer ambiguity of the phase difference will influence the DF because the distance between elements is larger than half the wavelength. Therefore, the system adopts the stagger baseline method to solve integer ambiguity 8 …”

A Channel Compensation Technique Based on Frequency-Hopping Binary Offset Carrier Modulated Signal

“…Furthermore, standing in the field of integrated communication and measurement system research, where the theme naturally matches the background of space-to-air communication, scholars have conducted numerous related studies so far. Based on BOC modulation as an extend from original spread spectrum modulation offering better performance in measurement, reference [22] proposed a combination with the introduction of a frequency-hopping technique as frequency-hopping binary offset carrier (FH-BOC) modulation to strengthen anti-interference capability, where multipath interference has also been discussed as outperforming the binary phase shift keying (BPSK) signal and BOC signal in circumstances. Subsequently, reference [23] conducted a FH-BOC signal further, converting it into an efficient constant envelope multiplexing technique for easily integrating signal components, in which the results showed it possessing lower ambiguity and better multipath performance than other BOC signals designed in a constant envelope under the same conditions.…”

A New Frequency Hopping Signal Detection of Civil UAV Based on Improved K-Means Clustering Algorithm

“…to monitor the UAV frequency band all-weather, analyze the spectrum data, then detect the control signal or the communication signal. Compared with these methods, spectrum monitoring has the advantages of good applicability and less influence by the environment, become an important method for UAV discovery [6][7][8][9][10] [28].…”