A Survey on Wireless Position Estimation <s> Other Position Related Parameters <s> This paper proposes a mobile user location scheme for wideband code-division multiple-access (CDMA) wireless communication systems. To achieve high location accuracy and low cost of the mobile receiver, the location scheme combines the time difference of arrival (TDOA) measurements from the forward link pilot signals with the angle of arrival (AOA) measurement from the reverse link pilot signal. High chip rates in wideband CDMA systems facilitate accurate TDOA measurements, and a smart antenna used at the home base station (BS) can provide accurate AOA measurement in a macrocell environment. A two-step least square location estimator is developed based on a linear form of the AOA equation in the small error region. Numerical results demonstrate that the proposed hybrid TDOA/AOA location scheme gives a much higher location accuracy than TDOA only location, when the number of base stations is small and/or when the TDOA measurements have a relatively poor accuracy. <s> BIB001 </s> A Survey on Wireless Position Estimation <s> Other Position Related Parameters <s> The Cramer-Rao bound (CRB) on location estimation accuracy of two different hybrid schemes, time of arrival/received signal strength (TOA/RSS) and time difference of arrival/received signal strength (TDOA/RSS), is computed. For short-range networks, the hybrid schemes offer improved accuracy with respect to conventional TOA and TDOA schemes, particularly in the proximity of the reference devices. <s> BIB002 </s> A Survey on Wireless Position Estimation <s> Other Position Related Parameters <s> The location of people, mobile terminals and equipment is highly desirable for operational and safety enhancements in the mining industry. In an indoor environment such as a mine, the multipath caused by reflections, diffraction and diffusion on the rough sidewall surfaces, and the non-line of sight (NLOS) due to the blockage of the shortest path between transmitter and receiver are the main sources of range measurement errors. Due to the harsh mining environment, unreliable measurements of location metrics such as RSS, AOA and TOA/TDOA result in the deterioration of the positioning performance. Hence, alternatives to the traditional parametric geolocation techniques have to be considered. In this paper, we present a novel method for mobile station location using wideband channel measurement results applied to an artificial neural network (ANN). The proposed system, the Wide Band Neural Network-Locate (WBNN-Locate), learns off-line the location 'signatures' from the extracted location-dependent features of the measured channel impulse responses data for LOS and NLOS situations. It then matches on-line the observation received from a mobile station against the learned set of 'signatures' to accurately locate its position. The location accuracy of the proposed system, applied in an underground mine, has been found to be 2 meters for 90% and 80% of trained and untrained data, respectively. Moreover, the proposed system may also be applicable to any other indoor situation and particularly in confined environments with characteristics similar to those of a mine (e.g. rough sidewalls surface). <s> BIB003 </s> A Survey on Wireless Position Estimation <s> Other Position Related Parameters <s> We introduce geo-regioning as a method to achieve rough localization in asynchronous UWB networks. The ap- proach is to localize the transmitter position by means of the multipath components in the received channel impulse response (signature). To show the principle feasibility of this approach a first regioning algorithm is introduced and tested with measured data. Therefore, a measurement campaign in a rich multipath environment has been performed. A high number of signatures originating from different regions in a room have been collected. The regioning algorithm presented here is based on the a priori knowledge of the average power delay profiles of the different regions. The performance results show that almost all regions can be localized at reasonable SNR and error probability. We conclude that the geo-regioning approach is a promising alternative or supplement to classical time of arrival based approaches in UWB networks. <s> BIB004 </s> A Survey on Wireless Position Estimation <s> Other Position Related Parameters <s> Non-Line-of-Sight and multipath propagation conditions pose significant problems for most mobile terminal positioning approaches. In contrast, power delay profile fingerprinting (PDP-F) thrives on multipath propagation. This multipath extension of T(D)oA is based on matching an estimated power delay profile from one or several base stations (BSs) (or other transmitters (broadcast, ...)) with a memorized power delay profile map for a given cell. With a single BS, an absolute time reference is required as for ToA. With multiple BSs, that requirement can be dropped as in TDoA. We propose a validation of PDP-F via simulations that can easily be reproduced. The multicellular environment consists of a big box in which multipath arises by reflection off the six sides. The resulting PDP depends on the positions of BS and terminal, the attenuation mechanism and the reflection coefficients of the six sides. We also propose an extension of the PDP-F (PSDP-F) taking into account spatial information available with an multi-antenna reception. PSDP-F can be considered as a multipath extension of the combined T(D)oA and AoA methods, without explicit requirement for antenna array calibration. <s> BIB005
In some positioning systems, two or more of the position related parameters, studied in the previous subsections, can be employed in order to obtain more information about the position of the target node. Examples of such hybrid schemes include TOA/AOA BIB001 , TOA/RSS BIB002 and TDOA/AOA BIB001 , TOA/TDOA  positioning. In addition to the RSS, AOA and T(D)OA parameters and their combinations, another scheme for position related parameter estimation involves obtaining multipath power delay profile (PDP) or channel impulse response (CIR) related to a received signal  , BIB005 , BIB004 , BIB003 . In some cases, PDP or CIR estimation can provide significantly more information about the position of the target node than the previously studied schemes. However, extracting the position information from such parameters commonly requires a database consisting of previous PDP (or CIR) estimates. Therefore, algorithms employing PDP or CIR estimation implement training phases, before the actual position estimation process begins. Similar to the PDP approach, multipath angular power profile parameter can be estimated at nodes with antenna arrays. Note that both the PDP (CIR) and the angular power profile estimation increase the complexity of the first step in the two-step positioning algorithm in Figure 1 -b compared to the conventional RSS, AOA and T(D)OA schemes, since a large number of unknown parameters need to be estimated in the former case. However, such parameters can also facilitate accurate position estimation in challenging environments BIB003 .