The Performance of the Arctangent Bearing Estimator in Isotropic Noise

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Authors
  1. Maranda, B.H.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
One well-known system for estimating the bearing to an underwater acoustic source consists of two crossed dipoles and an omni-directional hydrophone. The bearing is computed from the sensor data using an estimator based on the arctangent function. In this paper, the performance of the arctan bearing estimator is examined for a sinusoidal signal is isotropic Gaussian noise. It is shown analytically that the estimator is unbiased, and an exact formula for the bearing variance is derived; this formula is valid for an arbitrary number of data blocks and arbitrary values of the signal-to-noise ratio (SNR). Numerical examples show that the variance of the arctan estimator approaches the Cramer-Rao lower bound for high SNRs, and the threshold region below which the bearing accuracy rapidly degrades is clearly identified. Two different strategies are compared for averaging multiple data blocks while forming the bearing estimate.
Keywords
Bearing errors;Bearing estimation;Noise;Dipoles;Arctangent;Localization;Variance;Omni-directional hydrophones
Report Number
DREA-TM-1999-145 — Technical Memorandum
Date of publication
01 Sep 1999
Number of Pages
34
DSTKIM No
CA000097
CANDIS No
512293
Format(s):
Hardcopy;Document Image stored on Optical Disk

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