【導讀】系統(tǒng)，并設計實現(xiàn)了一種基于權重值選擇的定位算法。AP的RSSI設定了選擇區(qū)間，指紋庫中落在此區(qū)間的所有位置點設平均權值，位的影響，提高了定位的穩(wěn)定性和精度。經實驗測試，此系統(tǒng)在4米范圍內具。有良好的定位效果?？刹渴鹪谡桂^、校園、公園等公共場所，為客戶提供定位。定位算法運行于服務端，客戶端為配備WiFi模塊的Android手。借助該定位系統(tǒng)，基于Android系統(tǒng)的移動終端可方便地查詢自身位置，并獲取各種基于位置服務。

　　

【正文】 圖分布與正態(tài)分布曲線近似， 因此均值 在一定程度上代表了 RSSI 特征。這也避免了 單次掃描的信號強度中某個 AP 的 RSSI 不穩(wěn) 定造成的定位結果偏差。 第 32 頁 共 40 頁 圖 11 RSSI 的統(tǒng)計特性 時間復雜度分析 ： 一次掃描有 m 個 AP， 前期訓練階段有 n 個位置點，則要進行 m 次 選擇，每次選擇遍歷 n 個位置點，時間復雜度 為 O(m*n)，遇到權值一致的情況，要進行二 次選擇，最壞情況再比較 n 次，時間復雜度為 O(n)，所以總的時間復雜度為 O(m*n)。 4. 7 實驗 . 1 實驗過程 實驗在計算所 6 層進行， 見圖 12， 在南北 兩側走廊總共采集了 24 個位置點，距離約 4 米，加上在 645 房間，總共 25 個位置點的數(shù) 據(jù)。掃描周期 1s，掃描 次數(shù) 120 次。采集數(shù)據(jù) 耗時約 1 小時。 圖 12 實驗環(huán)境 第 33 頁 共 40 頁 本實驗主要為驗證定位準確性， 所以定位 時采用多次掃描的均值作為信號特征。 共選取 了 6 個位置點作為實驗的位置點。 測試次數(shù)約 為 50 次，掃描周期為 2s，運行界面見圖 13。 圖 13 手機終端顯示 . 實驗結果 各實驗位置點的結果見圖 14。 各個隨機測 試位置點的定位準確率都較高。 圖 14 各實驗位置點定位結果 . 總結 本文基于 Android 智能手機平臺，設計并 實現(xiàn)了一種基于 WiFi 信號的移動終端定位系 統(tǒng)，并提出了一種基于權值選擇的定位算法， 一定程度上克服 RSSI 信號隨機擾動帶來的定 位誤差，經過實際環(huán)境的測試，多次定位實驗 的精度在 4 米左右，適當調整 AP 的布置可以 進一步定位精度。本系統(tǒng)可方便地部署到展 館、校園等實際場景中。 第 34 頁 共 40 頁 致謝 在這篇論文完成之際，在此我衷心的感謝我的指導老師史永老師。老師在百忙之抽出寶貴的時間來為我認真細心的指導講解，并提出了許多寶貴的意見和建議，在老師全力的指導下我終于完成了論文，可以說沒有老師的輔導就沒有我今天的論文，更 加是難以完成，十分感謝我的指導老師。在即將離開學校之際，再次由衷的感謝我系所有老師對我的幫助，謝謝你們?yōu)槲业拇髮W生活劃上一個完滿的句號！ 第 35 頁 共 40 頁 參考文獻 [1] Veljo Otsason. Accurate Indoor Localization Using Wide GSM Fingerprinting. Master’s Thesis, Institute of Computer Science, University of Tartu, 2021 [2] 韓霜 ，羅海勇，陳穎，丁玉珍．基于 TDOA 的超聲波室內定 位系統(tǒng)的設計與實現(xiàn)．傳感技術學報， 23（ 3） ： 347~353， 2021 [3] Paramvir Bahl and Venkata N. Padmanabhan. RADAR: An InBuilding RFbased User Location and Tracking System. IEEE info,774~784,2021 [4] Kamol Kaemarungsi. Design of Indoor Positioning Systems Based on Location Fingerprinting Technique. Doctor’s Thesis. School of Information Science. University of Pittsburgh. 2021. [5] Madigan D, Elnahrawy E, Martin R P, et al. Bayesian Indoor Positioning Systems. Proceedings of the 24th Annual Joint Conference of the IEEE Computer and Communications Societies,1217~1227,2021 [6]葉世榕 .GPS 非差相位精密單點定位理論與實現(xiàn) [D].武漢：武漢大學，2021. [7]徐紹銓 ,張華海 ,楊志強 ,王澤民 .GPS 測量原理及應用 [M].武漢：武漢大學出版社， 2021. 第 36 頁 共 40 頁 [8]劉焱雄 ,周興華 ,張衛(wèi)紅 ,吳永亭 .GPS 精密單點定位精度分析 [J].海洋測繪，2021， 25（ 1）： 4446. [9]Zumberge J F,Heflin M B,Jefferson D C,et al (1997).Precise Point Positioning for the Efficient and Robust Analysis of GPS Data from Large Networks[J].Journal of Geophysical Research,1997,102(B3):5 0055 017. [10]宋偉偉，姚宜斌，羅峰 .精密單點定位中周跳探測與修復方法研究 [J].測繪信息與工程， 2021， 32（ 3）： 3436. [11] [12] J. Bardwell. Converting Signal Strength Percentage to dBm Values. White Paper, 2021. [13] KwokWai Cheung, Jonathan . Sau, and R. D. Murch, A New Empirical Model for Indoor Propagation Prediction. IEEE Transactions On Vehicular Technology. 47(3), 1998 [14] Ville, Tommi, et al. A Comparative Survey of WLAN Location Fingerprinting Methods. Proc. of the 6th Workshop on Positioning, Navigation and Communication 2021, 243~251,2021 [15] 林以明，羅海勇，李錦濤，趙方．基于動態(tài) Radio Map 的粒 子濾波室內無線定位算法．計算機研究與發(fā)展， 2021 [16] 趙方，馬嚴，羅海勇，林權．基于核函數(shù)法及馬爾可夫鏈的 節(jié)點定位技術．第三屆中國傳感器網絡學術會議， 36（ 10） ： 102~105， 2021 開放性和擴展性。 g an employment tribunal clai Employment tribunals sort out disagreements between employers and employees. You may need to make a claim to an employment tribunal if: ? you don39。t agree with the disciplinary action your employer has taken against you ? your employer dismisses you and you think that you have been dismissed unfairly. For more information about dismissal and unfair dismissal, see Dismissal. You can make a claim to an employment tribunal, even if you haven39。t appealed against the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any pensation awarded to you as a result of your failure to appeal. Remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are plaining about happened. If your application is received after this time limit, the tribunal will not usually accept i. 第 37 頁 共 40 頁 If you are worried about how the time limits apply to you, take advice from one of the anisations listed under Further help. Employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation. Most people find making a claim to an employment tribunal challenging. If you are thinking about making a claim to an employment tribunal, you should get help straight away from one of the anisations listed under Further help. If you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your pensation if you win the case. This is known as a damagesbased agreement. In England and Wales, your solicitor can39。t charge you more than 35% of your pensation if you win the case. If you are thinking about signing up for a damagesbased agreement, you should make sure you39。re clear about the terms of the agreement. It might be best to get advice from an experienced adviser, for example, at a Citizens Advice Bureau. To find your nearest CAB, including those that give advice by , click on nearest CAB. For more information about making a claim to an employment tribunal, see Employment tribunals. The (lack of) air up there Watch mCayman Islandsbased Webb, the head of Fifa39。s antiracism taskforce, is in London for the Football Association39。s 150th anniversary celebrations and will attend City39。s Premier League match at Chelsea on Sunday. I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC Sport. For me it39。s about how he felt and I would like to speak to him first to find out what his experience was. Uefa has opened disciplinary proceedings against CSK