GVINS
GVINS 在 VINS-Mono 的滑動視窗非線性最佳化中,直接加入 GNSS 原始量測(碼偽距與都卜勒頻移)以及接收器時鐘偏差與漂移因子,與影像及 IMU 緊耦合,提供無漂移的全域六自由度位姿。系統先以單點定位得到粗略錨點,再用都卜勒量測校正區域座標與 ENU 座標間的偏航角,最後以偽距精修錨點,完成線上初始化。對低速、衛星少於 4 顆與完全無 GNSS 的退化情況分別處理,可在室內外轉換時衛星遺失與重新鎖定之間連續運作。
本頁內容
GVINS tightly fuses raw GNSS pseudorange and Doppler with visual-inertial data in a sliding-window factor graph, using a coarse-to-fine online initialisation of the local-to-ENU yaw and anchor, and explicit handling of degenerate cases, to give drift-free global 6-DoF estimates across indoor-outdoor transitions.
技術屬性
欄位內容為文獻擷取紀錄的原文用語(英文),以原文為據;「未查證」表示本研究尚未讀到該資訊,不代表該方法不具備此能力。
| 感測輸入 | monocular camera (left camera of a VI-Sensor)、IMU、GNSS receiver raw code pseudorange and Doppler (GPS, GLONASS, Galileo, BeiDou) |
|---|---|
| 原文測試平台 | helmet-mounted (walking: sports field; indoor-outdoor route over 3 km with stairs)、urban driving (22.9 km in Hong Kong; vehicle mounting not described)、simulation (10 km trajectory in a 30 m cube) |
| 狀態估計 | tightly coupled sliding-window non-linear optimisation (window size 10) on a factor graph inherited from VINS-Mono: IMU preintegration, visual reprojection, GNSS code pseudorange and Doppler factors, receiver clock bias and drift factors; states include the yaw offset between local world and ENU frames and per-constellation clock biases; two-way marginalisation; robust norm on GNSS factors in urban driving (Secs. V, VI, VIII-B5) |
| 資料關聯 | strong corners tracked with iterative Lucas-Kanade optical flow (VINS-Mono front end); GNSS satellites filtered by elevation, health and continuous lock (Secs. V, VI-C) |
| 時間表示 | discrete keyframe states; GNSS time aligned to local time beforehand via the receiver PPS signal triggering the VI-Sensor (Secs. III-A, VIII-B) |
| 去畸變 | 不適用 |
| 迴圈閉合 | none (VINS-Mono and VINS-Fusion loop closure also disabled in the comparisons) |
| 全域最佳化 | none; global drift-free estimation comes from GNSS raw-measurement factors inside the sliding window rather than from loop closure |
| 地圖表示 | sparse features with inverse depth in the sliding window |
| 先驗資訊 | broadcast ephemeris; Saastamoinen tropospheric and Klobuchar ionospheric models; no base station needed for the estimator (RTK used only as ground truth) (Secs. IV-D, VIII-B) |
| 可輸出幾何 | global 6-DoF pose in ECEF and a local ENU frame, including global yaw; no dense map |
| 計算需求 | Intel i7-8700K at 3.7 GHz, 32 GB: feature detection and tracking 7.28 ms per frame and window optimisation 21.91 ms on the urban sequence, real time with a 20 Hz camera (Sec. VIII-B5) |
使用設備
原文使用的感測器、運算硬體與載具(equipment)。型號保留原文寫法,連結到設備頁中同一型號的歸併名稱;角色依原文用途分為方法輸入、資料集感測器、執行運算平台、參考或真值量測(reference or ground truth)與比較對象設備。
| 類別 | 型號(原文寫法) | 角色 | 資料集 | 原文規格 | 出處 |
|---|---|---|---|---|---|
| 慣性量測單元(IMU) | ADIS16448 | 方法輸入 | GVINS-Dataset | 200 Hz; gyroscope noise density 7.0e-3 deg/s/sqrt(Hz); accelerometer noise density 6.6e-4 m/s^2/sqrt(Hz) | (Cao et al., 2022, Table IV) |
| GNSS 接收器 | u-blox ZED-F9P | 方法輸入 | GVINS-Dataset | low-cost multi-band, multi-constellation receiver; raw measurements at 10 Hz | (Cao et al., 2022, Sec. VIII-B; Table IV) |
| GNSS 接收器 | u-blox ZED-F9P internal RTK engine with RTCM from a nearby base station | 參考或真值量測 | GVINS-Dataset | RTK solution at 10 Hz; about 1 cm accuracy in open areas; fails indoors and under heavy blockage | (Cao et al., 2022, Sec. VIII-B; Table IV) |
| GNSS 接收器 | Tallysman TW3882 antenna | 方法輸入 | GVINS-Dataset | GNSS antenna of the receiver | (Cao et al., 2022, Table IV) |
| 雙目相機 | VI-Sensor (Aptina MT9V034 camera sensors; left camera used) | 方法輸入 | GVINS-Dataset | global shutter, 752 x 480, horizontal FOV 98 deg, vertical FOV 73 deg, 20 Hz; camera and IMU synchronised by the VI-Sensor and triggered by the GNSS PPS | (Cao et al., 2022, Sec. VIII-B; Table IV) |
| 載具平台 | helmet carrying the VI-Sensor and ZED-F9P | 方法輸入 | GVINS-Dataset | used in the real-world experiments | (Cao et al., 2022, Fig. 10) |
| 運算硬體 | Intel i7-8700K at 3.7 GHz, 32 GB | 執行運算平台 | 未標示 | desktop PC used for all experiments | (Cao et al., 2022, Sec. VIII) |
作者報告的優勢與限制
優勢
- RMSE 0.806 m (sports field), 3.700 m (indoor-outdoor) and 4.508 m (22.9 km urban driving) versus 2.835 m, 6.036 m and 11.106 m for RTKLIB SPP (Table III)
- Survives the whole urban sequence where VINS-Mono failed at 54% of the distance and VINS-Fusion oscillated with RMSE on the order of 10^5 m (Sec. VIII-B5)
- Still benefits from fewer than four satellites, even a single satellite, compared with pure VIO (Sec. VIII-B2; Figs. 13-14)
- Keeps global estimates indoors and on stairs where RTK showed errors up to 80 m during outages (Sec. VIII-B3; Figs. 1, 16)
- Window optimisation 21.91 ms versus an average 404.83 ms (up to 1018.46 ms) for the VINS-Fusion pose-graph fusion (Sec. VIII-B5)
限制
- Global positions carry a bias from satellite orbit error, imperfect atmospheric delay models and multipath, especially in the up direction (Secs. VIII-B1, VIII-B3, VIII-B5)
- With three or fewer satellites the up-direction drift is no longer removed; with two or one satellite horizontal and yaw drift appear (Sec. VIII-B2)
- Low-speed or rotation-only motion cannot constrain the yaw offset, which is fixed below 0.3 m/s (Sec. VII-B1)
- Initialisation needs at least four satellites (N+3 for N constellations) and about 4 m of travel, and can wait several seconds for ephemerides (Secs. VII-A, VIII-B3)
- Doppler-only operation drifts and keeps the initialisation bias (Sec. VIII-B4)
營建工程相關證據
論文未在營建工地測試;實驗包括校園運動場、含室內樓梯、橋下與樹林的 3 km 室內外路線,以及香港 22.9 km 市區行車,並以 RTK 為參考。它能在衛星時有時無的室內外轉換中持續提供全域位姿,對把相機慣性軌跡或點雲地理參考到工地座標、以及在高樓遮蔽處維持定位有參考價值;但全域位置仍有公尺級偏差,不足以直接作為測量控制(推論)。
原文驗證環境:模擬、獨立參考量測
報告的性能數據
性能數據仍在分批查證,目前尚未收錄此方法的報告值。
來源
Cao et al., 2022
(2022)GVINS: Tightly Coupled GNSS–Visual–Inertial Fusion for Smooth and Consistent State EstimationIEEE Transactions on Robotics, 38(4):2004-2021
DOI 10.1109/tro.2021.3133730arXiv 2103.07899程式碼
同儕審查已出版已讀全文近十年查證後修正
相關版本
- 預印本:GVINS: Tightly Coupled GNSS-Visual-Inertial Fusion for Smooth and Consistent State Estimation (arXiv v1 to v3) https://arxiv.org/abs/2103.07899
- 程式碼釋出:HKUST-Aerial-Robotics/GVINS https://github.com/HKUST-Aerial-Robotics/GVINS
- 資料集:HKUST-Aerial-Robotics/GVINS-Dataset (well-synchronised camera, IMU and GNSS raw data with RTK ground truth, per the paper) https://github.com/HKUST-Aerial-Robotics/GVINS-Dataset
程式碼:https://github.com/HKUST-Aerial-Robotics/GVINS(授權:GPL-3.0 (README licence section))。有公開程式碼不等於已被重現,也不代表目前版本與論文版本相同。