目錄
COMPARISON OF BASIC METHODS AND POSITIONING SYSTEMS
CONCLUSION, SUMMARY, AND FUTURE APPLICATIONS
各種基本方法以及定位系統的對比：
This section compares basic localization methods and positioning systems in Tables 1.1 and 1.2 .
Several positioning parameters are used to compare different methods.
基本定位方法精度的标度：高（H），0 - 50; 中（M），50-100; 低（L），> 100。
Table 1.1 compares basic positioning methods previously discussed in the chapter in terms of accuracy, a need for the availability of LOS, and the number of base stations required for localization.
表1.1比較了本章前面讨論的基本定位方法的準确性，對LOS可用性的需求以及定位所需的基站數量。
The table shows that on average, the accuracy of the DOA estimate is poorer relative to TOA, TDOA, and RSSI estimates. This is mainly due to the fact that as the distance between the base station and the target increases, a small DOA error leads to a higher localization error. The DOA error is very sensitive to the multipath environment and the signal - to - noise ratio [23] .
該表顯示，平均而言，相對于TOA，TDOA和RSSI估計，DOA估計的準确性較差。 這主要是由于随着基站和目标之間的距離增加，小的DOA誤差導緻更高的定位誤差。 DOA誤差對多徑環境和信噪比非常敏感[23]。
Complex algorithms could be used to improve the DOA performance. DOA performance in localization methods such as WLPS can be improved by incorporating its periodic transmission nature [24, 25] .
複雜算法可用于改善DOA性能。 通過結合其周期性傳輸特性，可以改善諸如WLPS的定位方法中的DOA性能[24,25]。
RSSI is different from other methods when the availability of LOS is taken into account, since it operates in both LOS and NLOS environments. Other localization techniques are very sensitive to the availability of LOS.
當考慮LOS的可用性時，RSSI與其他方法不同，因為它在LOS和NLOS環境中都運作。 其他定位技術對LOS的可用性非常敏感。
Table 1.2 compares different positioning systems based on several parameters.
The following observations can be made from the table:
• Most of the systems that operate based on the availability of LOS propagation have higher accuracy. Thus, NLOS introduces error in the calculation, decreasing the accuracy.
• Many existing positioning systems employ multiple base nodes to localize the target node. This may create a system cost problem for the designer.
• The power consumption for most positioning systems is medium to very low. Thus, using one of the low - power positioning systems does not impose additional constraint on the designer with respect to the required power consumption.
• All positioning systems except RFID - based systems can support mobility.
• Many positioning systems are well suited for both outdoor and indoor environments.
•基于LOS傳播可用性運作的大多數系統具有更高的準确性。 是以，NLOS在計算中引入誤差，降低了精度。
•許多現有定位系統使用多個基節點來定位目标節點。 這可能會給設計人員帶來系統成本問題。
•大多數定位系統的功耗從中到低。 是以，使用低功率定位系統之一不會對設計者施加額外的限制，即所需的功耗。
•除基于RFID的系統外，所有定位系統均可支援移動性。
•許多定位系統非常适合室外和室内環境。
a:
Scale for accuracy of positioning systems: very high (VH), < 1; high (H), 1 – 5; medium (M), 5 – 30; low (L), 30 – 50; very low (VL), > 50.
定位系統精度的标度：非常高（VH），<1; 高（H），1 - 5; 中（M），5 - 30; 低（L），30 - 50; 非常低（VL），> 50。
b:
Scale for power consumption of positioning systems: very low (VL), < 1; low (L), 1 – 10; moderate (M), 10 – 50; high(H), 50 – 200; very high (VH), > 200.
定位系統功耗的标度：非常低（VL），<1; 低（L），1 - 10; 中度（M），10 - 50; 高（H），50 - 200; 非常高（VH），> 200。
c:
The initial accuracy is high (few decimeters), which changes with time due to error propagation.
初始精度很高（幾個分米），由于誤差傳播而随時間變化。
d:
Depends on INS classification (stable platform system consumes high power; strapdown system consumes moderate power).
取決于INS分類（穩定平台系統消耗高功率;捷聯系統消耗中等功率）。
e:
The initial accuracy is low (few degrees), which decreases with distance.
初始精度很低（幾度），随着距離的增加而減小。
f:
The detection range of the vision system is 1 – 95 m, which determines the accuracy.
視覺系統的檢測範圍是1-95米，這決定了準确性。
g:
Within the high range, the power consumption depends on the peak power output.
在高範圍内，功耗取決于峰值功率輸出。
h:
In GPS and AGPS, satellites are considered as base stations.
在GPS和AGPS中，衛星被視為基站。
O, outdoor; I, indoor; N/A, not applicable.
Figure 1.5 Futuristic applications of positioning systems.
The existing positioning systems are used in numerous applications that will likely be expanded in the future, in response to new demands. As shown in Figure 1.5 , the future entails collaboration among various positioning systems especially for applications related to situation awareness.
現有的定位系統被用于許多應用中，這些應用将來可能會根據新的需求進行擴充。 如圖1.5所示，未來需要各種定位系統之間的協作，特别是與情境感覺相關的應用。
For example, in the case of an automatically driven car, the information on the road condition and traffic (situation awareness) may be obtained using various existing positioning systems such as GPS, radar [38] , and WLPS. As shown in the figure, the automatically driven car can derive information such as the distance of the surrounding traffi c using radar and WLPS. GPS can help the automatically driven car to recognize roadblocks caused by accident or other factors such as traffi c. Thus, in this example, the automatically driven car can be aware of its situation using the positioning technologies.
例如，在自動駕駛汽車的情況下，可以使用諸如GPS，雷達[38]和WLPS之類的各種現有定位系統來獲得關于道路狀況和交通（情況感覺）的資訊。 如圖所示，自動駕駛汽車可以使用雷達和WLPS獲得諸如周圍交通的距離之類的資訊。 GPS可以幫助自動駕駛汽車識别由事故或其他因素（如交通）引起的路障。 是以，在該示例中，自動駕駛汽車可以使用定位技術了解其情況。
In another example that is shown in the figure, a soldier on a reconnaissance or rescue mission can use the information from a vision system, radar, and GPS to be aware of his surroundings or situation. Also shown in the figure is the police car that keeps track of the thief and road conditions using signals from several positioning systems. Miners can also benefi t from the positioning systems such as INS and RFID to be aware of their current location and possible escape route in case of emergency. For the miners, it can be envisioned that RFID tags are installed along the mine tunnels as it is explored deeper in the earth ’ s crust. The information from these RFID tags can potentially include the depth of the mine, the soil characteristics, and so on.
在圖中示出的另一示例中，偵察或救援任務中的士兵可以使用來自視覺系統，雷達和GPS的資訊來了解他的周圍環境或情況。 圖中還顯示了使用來自多個定位系統的信号跟蹤小偷和道路狀況的警車。 礦工還可以從INS和RFID等定位系統中獲益，以便在緊急情況下了解其目前位置和可能的逃生路線。 對于礦工來說，可以設想RFID标簽沿着礦井隧道安裝，因為它在地殼的深處探測。 來自這些RFID标簽的資訊可能包括礦井的深度，土壤特征等。
Finally, also shown in the figure is a ship that gathers information from a number of systems and selects its course accordingly. It should be noted that the figure provides only some of the applications where positioning systems collaborate among themselves or with other systems (e.g., a weather forecast system) for situation awareness.
最後，圖中還顯示了一艘船，它從許多系統收集資訊并相應地選擇其路線。 應當注意，該圖僅提供了定位系統在它們之間或與其他系統（例如，天氣預報系統）協作以用于情況感覺的一些應用。
This handbook reviews the details of many localization techniques that have been briefl y introduced in this chapter.