A Dataset of Outdoor RSS Measurements for Localization

Dataset Description

This dataset is a large-scale set of measurements for RSS-based localization. The data consists of received signal strength (RSS) measurements taken using the POWDER Testbed at the University of Utah. Samples include either 0, 1, or 2 active transmitters.

The dataset consists of 5,214 unique samples, with transmitters in 5,514 unique locations. The majority of the samples contain only 1 transmitter, but there are small sets of samples with 0 or 2 active transmitters, as shown below. Each sample has RSS values from between 10 and 25 receivers. The majority of the receivers are stationary endpoints fixed on the side of buildings, on rooftop towers, or on free-standing poles. A small set of receivers are located on shuttles which travel specific routes throughout campus.

The transmitters for this dataset are handheld walkie-talkies (Baofeng BF-F8HP) transmitting in the FRS/GMRS band at 462.7 MHz. These devices have a rated transmission power of 1 W. The raw IQ samples were processed through a 6 kHz bandpass filter to remove neighboring transmissions, and the RSS value was calculated as follows:

\(RSS = \frac{10}{N} \log_{10}\left(\sum_i^N x_i^2 \right) \)

Receivers consist of Ettus USRP X310 and B210 radios, and a mix of wide- and narrow-band antennas, as shown in the table below Each receiver took measurements with a receiver gain of 35 dB. However, devices have different maxmimum gain settings, and no calibration data was available, so all RSS values in the dataset are uncalibrated, and are only relative to the device.

Usage Instructions

Data is provided in .json format, both as one file and as split files.

import json
data_file = 'powder_462.7_rss_data.json'
with open(data_file) as f:
    data = json.load(f)

The json data is a dictionary with the sample timestamp as a key. Within each sample are the following keys:

• rx_data: A list of data from each receiver. Each entry contains RSS value, latitude, longitude, and device name.
• tx_coords: A list of coordinates for each transmitter. Each entry contains latitude and longitude.
• metadata: A list of dictionaries containing metadata for each transmitter, in the same order as the rows in tx_coords

File Separations and Train/Test Splits

In the separated_data.zip folder there are several train/test separations of the data.

• all_data contains all the data in the main JSON file, separated by the number of transmitters.
• stationary consists of 3 cases where a stationary receiver remained in one location for several minutes. This may be useful for evaluating localization using mobile shuttles, or measuring the variation in the channel characteristics for stationary receivers.
• train_test_splits contains unique data splits used for training and evaluating ML models. These splits only used data from the single-tx case. In other words, the union of each splits, along with unused.json, is equivalent to the file all_data/single_tx.json.
  • The random split is a random 80/20 split of the data.
  • special_test_cases contains the stationary transmitter data, indoor transmitter data (with high noise in GPS location), and transmitters off campus.
  • The grid split divides the campus region in to a 10 by 10 grid. Each grid square is assigned to the training or test set, with 80 squares in the training set and the remainder in the test set. If a square is assigned to the test set, none of its four neighbors are included in the test set. Transmitters occuring in each grid square are assigned to train or test. One such random assignment of grid squares makes up the grid split.
  • The seasonal split contains data separated by the month of collection, in April or July.
  • The transportation split contains data separated by the method of movement for the transmitter: walking, cycling, or driving. The non-driving.json file contains the union of the walking and cycling data.
  • campus.json contains the on-campus data, so is equivalent to the union of each split, not including unused.json.

Digital Surface Model

The dataset includes a digital surface model (DSM) from a State of Utah 2013-2014 LiDAR survey. This map includes the University of Utah campus and surrounding area. The DSM includes buildings and trees, unlike some digital elevation models.

To read the data in python:

import rasterio as rio
import numpy as np
import utm

dsm_object = rio.open('dsm.tif')
dsm_map = dsm_object.read(1)     # a np.array containing elevation values
dsm_resolution = dsm_object.res     # a tuple containing x,y resolution (0.5 meters) 
dsm_transform = dsm_object.transform     # an Affine transform for conversion to UTM-12 coordinates
utm_transform = np.array(dsm_transform).reshape((3,3))[:2]
utm_top_left = utm_transform @ np.array([0,0,1])
utm_bottom_right = utm_transform @ np.array([dsm_object.shape[0], dsm_object.shape[1], 1])
latlon_top_left = utm.to_latlon(utm_top_left[0], utm_top_left[1], 12, 'T')
latlon_bottom_right = utm.to_latlon(utm_bottom_right[0], utm_bottom_right[1], 12, 'T')

Dataset Acknowledgement: This DSM file is acquired by the State of Utah and its partners, and is in the public domain and can be freely distributed with proper credit to the State of Utah and its partners. The State of Utah and its partners makes no warranty, expressed or implied, regarding its suitability for a particular use and shall not be liable under any circumstances for any direct, indirect, special, incidental, or consequential damages with respect to users of this product.

DSM DOI: https://doi.org/10.5069/G9TH8JNQ