MIMO radars are focused on target localization accuracy, i.e., the x-y coordinate or the x-y velocity of a target, leave a message while NGR cares about time delay differences and total phase differences with respect to the target, i.e., the CPs. Second, the parameters of phases are modeled and treated differently in NGR and MIMO radar. In MIMO radar, phase synchronization errors are modeled as random variables which are used to evaluate the average performance degradation [14�C16], and they Inhibitors,Modulators,Libraries need not to be estimated, thus their CRBs are of no interest, while in NGR the parameters of phases are modeled as deterministic unknowns that need to be estimated for compensation so their CRBs are of high concern.In this paper, we make the following contributions which also answer the questions at the end of paragraphs two and three.

Inhibitors,Modulators,Libraries All the contributions below are useful and instructive for the system design and performance analysis of NGR:(a)The NGR signal model based on a single pulse is extended to the case of pulse trains for the first time, and the concept of spatial coherence is extended to joint space-time coherence for NGR. The extension to pulse trains benefits the detection and tracking of weak targets and helps control the system scale of NGR.(b)The original coherence parameters (CPs) of NGR are extended to the generalized coherence parameters (GCPs), with Doppler frequencies involved. Since target echoes coming from different radars usually have different Doppler frequencies, they must also be estimated and compensated. The extension to GCPs is essential in characterizing the multi-pulse model in (a).

(c)The closed-form CRBs of the GCPs are derived based on the signal model in (a), and verified through simulations, Inhibitors,Modulators,Libraries thus providing a lower bound for the estimation accuracy of the GCPs and a criterion for the performance evaluation of different estimation algorithms.(d)The formula of coherence gain for NGR is derived Inhibitors,Modulators,Libraries and the performance bound is analyzed based on the CRBs in (c) with all types of estimation errors considered, thus providing an upper bound for the SNR gain performance of NGR.The paper is organized as follows: in Section 2, we present the NGR signal model with pulse trains and specifically define the GCPs. In Section 3, we derive the CRB for parameter estimation. In Section 4, we present the analytical formula of coherence performance.

Simulation results and discussions are shown in Drug_discovery Section 5, and Section 6 concludes the paper.2.?System Model and Parameter DefinitionsThe system model of NGR with master-slave architecture is illustrated in Figure 1. Without loss of generality, we assume that there are K radars with Tubacin microtubule Radar No.1 being the master radar.Figure 1.The master-slave architecture of NGR.The pulse signal transmitted by the kth transmitter is:sk(t)ej2��fct+j��kt,k=1,?,K(1)where sk(t) is the baseband signal of the kth transmitter, fc is the carrier frequency, and ��kt represents the phase of the local oscillator at the kth transmitter.