Satellite Tracking Research Articles

Development of artificial Earth satellite simulation software for future radio telescopes in Indonesia

"In the near future, four radio telescopes will be installed in Indonesia. Besides the astronomical purposes, these telescopes are expected to support the ground station for tracking the Artificial Earth Satellites (AES). In this study, we focus on the development of AES simulation software, named AESSIMS, that can be used to aid Indonesian radio telescope engineers in tracking the AES. This software is interactive and web-based. It can track the AES position in real time as well as predict the position for the near future. This software provides information about when a satellite signal can be acquired and lost, which can be beneficial for radio telescopes to establish communication with the satellite. We visualize the use of this software by conducting a simulation of satellite tracking by Indonesian future radio telescopes. Three Indonesian satellites named LAPAN-A1/TUBSAT, LAPAN-A2/ORARI, and LAPAN-A3/IPB are considered in the simulation. This study demonstrates that AESSIMS simulation results for Indonesian satellites and radio telescopes are consistent with the results obtained from already existing satellite tracking simulation software."

Virtual coastal altimetry tide gauges along the West African coast

Low-lying coastal regions are generally vulnerable to climate change, and particularly to sea level variations. Understanding how these variations affect the coastal population requires an access to sea level measurements. Good quality in-situ sea level data are seldom available, with most long, research quality data in Europe and North America. In contrast, satellite altimetry provides more than three decades of near-global, continuous and freely available sea level measurements. Thanks to recent advances in processing and instruments, these observations have now become reliable to a few kilometers from the coast. In this study, using the available in-situ tide gauge data as a reference, we explore the ability of the recent X-TRACK/ALES high-resolution coastal altimeter product to derive the ocean tide and the long-term sea level changes along the West African coast. This region was chosen because it is under-sampled in terms of in-situ observations and would benefit greatly from the availability of freely accessible satellite data sets. To select the altimetry observations closest to the coast, we first define virtual tide gauges as close as possible to the intersection between each satellite track and the land. Sea level anomalies derived from the virtual stations were observed to be similar to those from the corresponding tide gauge stations: correlation values are between 0.58 and 0.78, root mean square differences between 5.6 and 8.3 cm. The virtual stations reproduce the observed tide with errors less or equal to 6.5 cm (i.e. 5.8% or less than the sea level variations of the tide). We show that part of the differences in tides between the two datasets is explained by differences in position between tide gauges and virtual stations. The combined analysis of sea level trends derived from tide gauges and from virtual stations shows how it is an efficient strategy to correct their respective errors and progress towards increasingly accurate sea level trend estimates in a region with little or no research-quality tide gauge data suitable for long-term sea level studies. The conclusion from this study is that in coastal regions poorly covered by tide gauges, our altimetry-based approach can be used to study and monitor sea-level variations related to tides or to long-term sea level changes.

Global temperature homogenization can obliterate temporal isolation in migratory animals with potential loss of population structure.

Climate change is expected to increase the spatial autocorrelation of temperature, resulting in greater synchronization of climate variables worldwide. Possibly such 'homogenization of the world' leads to elevated risks of extinction and loss of biodiversity. In this study, we develop an empirical example on how increasing synchrony of global temperatures can affect population structure in migratory animals. We studied two subspecies of bar-tailed godwits Limosa lapponica breeding in tundra regions in Siberia: yamalensis in the west and taymyrensis further east and north. These subspecies share pre- and post-breeding stopover areas, thus being partially sympatric, but exhibiting temporal segregation. The latter is believed to facilitate reproductive isolation. Using satellite tracking data, we show that migration timing of both subspecies is correlated with the date of snowmelt in their respective breeding sites (later at the taymyrensis breeding range). Snow-cover satellite images demonstrate that the breeding ranges are on different climate trajectories and become more synchronized over time: between 1997 and 2020, the date of snowmelt advanced on average by 0.5 days/year in the taymyrensis breeding range, while it remained stable in the yamalensis breeding range. Previous findings showed how taymyrensis responded to earlier snowmelt by advancing arrival and clutch initiation. In the predicted absence of such advancements in yamalensis, we expect that the two populations will be synchronized by 2036-2040. Since bar-tailed godwits are social migrants, this raises the possibility of population exchange and prompts the question whether the two subspecies can maintain their geographic and morphological differences and population-specific migratory routines. The proposed scenario may apply to a wide range of (social) migrants as temporal segregation is crucial for promoting and maintaining reproductive isolation in many (partially sympatric) migratory populations. Homogenization of previously isolated populations could be an important consequence of increasing synchronized environments and hence climate change.

Seasonally mediated niche partitioning in a vertically compressed pelagic predator guild.

Niche partitioning among closely related, sympatric species is a fundamental concept in ecology, and its mechanisms are of broad interest for understanding ecosystem functioning and predicting the impacts of human-driven environmental change. However, identifying mechanisms by which top marine predators partition available resources has been especially challenging given the difficulty of quantifying resource use of large pelagic animals. In the eastern tropical Pacific (ETP), three large, highly mobile and ecologically similar pelagic predators (blue marlin (Makaira nigricans), black marlin (Istiompax indica) and sailfish (Istiophorus platypterus)) coexist in a vertically compressed habitat. To evaluate each species' ecological niche, we leveraged a decade of recreational fisheries data, multi-year satellite tracking with high-resolution dive data, and stable isotope analysis. Fishery interaction and telemetry-based three-dimensional seasonal utilization distributions suggested high spatial and temporal overlap among species; however, seasonal and diel variability in diving behaviour produced spatial partitioning, leading to low trophic overlap among species. Expanding oxygen minimum zones will reduce the available vertical habitat within predator guilds, likely leading to increases in interspecific competition. Thus, understanding the mechanisms of habitat partitioning among predators in the vertically compressed ETP can provide insight into how predators in other ocean regions may respond to vertically limited habitats.

Satellite constellation method for ground targeting optimized with K-means clustering and genetic algorithm

This study proposed a satellite constellation method to cluster targets using machine learning and achieve the desired revisit performance for each target in an area of interest. Because a typical satellite constellation, such as the Walker method, does not consider the geometrical dynamics between the satellite and Earth's surface target, the target-oriented revisit performance analysis and the application of optimization method are limited. To overcome these limitations, this study developed a satellite constellation method that is customized according to the target using a repeating ground track orbit and machine learning techniques. The proposed model groups aim to maximize satellite revisit performance via K-means clustering and determine the optimal number of satellites required to achieve the desired revisit performance for each target through a quick and accurate accessibility analysis of various target distributions. This study revealed that three to five target clusters are more effective in improving the satellite revisit performance than a typical single target cluster, while identifying that the density of the target distribution is a significant influencing factor. Finally, the proposed model achieved the desired revisit performance, guaranteeing a timely response for 30 major disaster locations in East Asia and validating the model's optimal performance.

Snapshot GNSS receivers for low-effort, high-gain space situational awareness

This paper proposes a novel concept of using highly efficient Snapshot Global Navigation Satellite Systems (GNSS) receivers to provide precise position fixes of single or multiple satellites in Low-Earth Orbit (LEO) to improve upper atmospheric modeling and thus contribute to superior space situational awareness (SSA). While tracking of LEO satellites and the use of onboard GNSS receivers for drag measurements and upper atmosphere modeling are well-established techniques, the expected advent of snapshot GNSS receivers for spaceborne scientific applications will allow massive improvements on the GNSS sensor’s Size, Weight, Power and Cost (SWaP-C). With chip-size dimensions of 4x4 mm2, a mass of less than 5 gr, an average power level below 0.1 mW, snapshot receiver technology is expected to provide position fixes in space with an accuracy of ∼19 m (3D r.m.s.), which will surpass the accuracy of Two-Line Elements (TLE) provided by the US Joint Space Operations Center (JSpOC) by at least two orders of magnitude. Equally important to their SWaP-C benefits, Snapshot GNSS receivers will allow mission and spacecraft designers to trade onboard-processing requirements versus payload downlink requirements, leading to either minimum onboard processing or a minimum amount of downlinked data. In this research, we establish the concept and architectural overview of using snapshot GNSS receivers for SSA, including the role of using them in a Distributed Space System (DSS), and detail their characterization and performance in terms of the required GNSS hardware and the impact of these payload on the power budget, the link budget and the OnBoard Data Handling (OBDH) budget of a satellite. It will be shown that these receivers lend themselves especially to their use on femto-, pico- and nano-satellites, although integrated snapshot modules may be flown as auxiliary payloads on micro- or mini-satellites as well. While this work focuses on the implications of the use of snapshot GNSS receivers on spacecraft design for the use of upper atmosphere modeling and SSA, their use may open up other science applications which avoid the need for expensive high-grade GNSS receivers.

Antenna Systems with Wide-Angle Mechanoelectrical Beam Steering

Introduction. The active development of satellite communication networks determines the need for new antenna systems for ground terminals. The Sphere Federal program implies the commissioning of new satellite constellations for communication and remote sensing of the Earth. The Skif (providing broadband Internet access) and Express-RV (providing the Internet and communications for Arctic) satellite constellations are not geostationary, thus requiring constant satellite tracking even for stationary terminals. Deflecting structures operating on the principle of quasi-optical beam control make it possible to develop scanning antenna systems for organizing continuous satellite communications. Aim. Investigation of various types of dielectric structures for radiation pattern deflection and scanning antenna systems on their basis, as well as identification of a configuration with improved characteristics compared to the ideal structure in the shape of a dielectric wedge. Materials and methods. Mathematical modeling, electrodynamic modeling using CAD by the finite element method and the finite integration method, as well as an experimental study of an antenna system prototype in an anechoicchamber by measuring methods in the far-field and near-field of the antenna. Results. Electrodynamic simulation was carried out for three types of dielectric structures, analogues of a dielectric wedge, including a structure assembled from various dielectrics of fixed sizes with different dielectric constants; a structure of triangular dielectric plates; and a perforated dielectric structure. In addition, scanning antenna systems based on the presented configurations were analyzed. Radiation patterns were obtained for all structural types for various rotation angles of the deflecting systems. The structure assembled from various dielectrics of fixed sizes with different dielectric constants was found to possess the most optimal characteristics. This structure was used to develop a model for experimental confirmation of the conducted electrodynamic simulation. The maximum tilt angle of the radiation pattern was about 60°, the decrease in the directivity relative to the maximum value was 6 dB; for tilt angles up to 55°, the directivity degradation did not exceed 4 dB, the level of the side lobes did not exceed –12 dB (calculated) and –14 dB (measured). Conclusion. The results of studies into various types of structures for quasi-optical beam control of the radiation pattern show the possibility of using these configurations when creating low-profile antenna systems with wide-angle mechanoelectric scanning for organizing satellite communications for both mobile and stationary consumers using medium earth orbit spacecrafts.

A Comparative Study of Conventional Transition Model and Reverse Transition Model for Wireless and Radar Applications

Microstrip line-to-waveguide transitions (MLWT) finds various applications in the field of RADAR engineering, navigation science, medical electronics, household equipment, satellite tracking equipment, wireless communications etc. Conventionally, the MLWT is designed so that the microstrip line is inserted in E-plane and perpendicular to the waveguide’s side wall, while the microstrip probe’s radiating face is towards the waveguide’s open end port. In this paper, an MLWT has been designed for Ka-band applications and the transition has been designed in such a way that the radiating face of the inserted microstrip line probe is towards the short circuit end of the waveguide. The method is called the reverse transition method. The microstrip signal reflected from the short circuit end comes in additive phase with the traveling wave and the strength of the traveling wave increases. MLWT has been developed using this method and results for Ka-band applications are presented in this paper. This work reported more than 20 dB improvement in return loss (RL), 0.1dB improvement in insertion loss (IL) and almost 7 to 8% enhancement in 10dB fractional bandwidth compared to the conventional method. Comparative analysis of the two methods has been shown in tabular form at the end of the paper.

Photo‐identification and satellite telemetry connect southern right whales from South Georgia Island (Islas Georgias del Sur) with multiple feeding and calving grounds in the southwest Atlantic

AbstractThe sub‐Antarctic waters of South Georgia Island (Islas Georgias del Sur, SG/IG) are a regularly visited feeding ground for southern right whales (Eubalaena australis, SRW) in the southwest Atlantic. Satellite telemetry and photo‐identification records were compared to better understand the role of SG/IG in the SRW migratory network. We present the first insights from SRW satellite‐tracked from the SG/IG feeding ground, habitat use patterns in the Scotia Arc, and movements to Antarctic habitats. Photo‐identification comparisons to calving and feeding areas across the South Atlantic and a review of sightings of cetaceans reported from Bird Island (west of SG/IG) since 1979 illuminate long‐term habitat use patterns in SG/IG. We present the first recorded migratory movement between SG/IG and multiple countries: Argentina, Uruguay, and Brazil. Photo‐identification (1) linked SG/IG to a female SRW with a long‐term sighting history in Brazil, and (2) provided the first match between SG/IG and the western Antarctic Peninsula, suggesting the latter could extend the feeding area for southwest Atlantic SRW. Satellite tracking and opportunistic sightings suggest that shelf and coastal waters west of SG/IG represent an important multi‐season SRW feeding habitat and add to our overall understanding of habitats and ranges occupied by recovering southwest Atlantic SRW.

Satellite Tracking Reveals an Exploration of Migration Routes by White-Naped Cranes (Antigone vipio)

Satellite Tracking Reveals an Exploration of Migration Routes by White-Naped Cranes (Antigone vipio)

Interacciones potenciales entre embarcaciones menores y zonas de agregación de tortugas marinas en Isla Arena, Campeche

Within the Gulf of Mexico, five of the seven species of sea turtles are distributed and carry out essential stages of their life cycle. The marine habitats of sea turtles are subject to various threats, including bycatch and boat traffic. The aim of this study was to identify, in the marine portion of Isla Arena, Campeche, sites of use of space for its feeding, internesting, and migration stages, as well as potential zones of interaction with small vessels distributed in the study area. For this, satellite tracking of three species of post-nesting female sea turtles: 1 hawksbill turtle (Eretmochelys imbricata), 4 Kemp´s ridley turtle (Lepidochelys kempii), and 7 green turtle (Chelonia mydas), with which the home range was estimated, and through a grid of the study area made up of 170 hexagons of 21 km2 area, the sites of the intensity of space use were estimated for each life stage. With this information and the quantification of vessels identified in the marine area of Isla Arena from January 2017 to December 2019 through Sentinel-2 satellite images, the areas of greatest interaction in three different seasons were identified. As a result, the sites with the highest use of space in the feeding stage are the south and north of Isla Arena, while for internesting the line parallel to the coast is where the highest use occurred; for migration, most of the study area has a use that goes from high to regular. Regarding the potential interaction with boats, feeding season one (January to April) was the one that presented the greatest interaction in the north and south of Isla Arena, while the west and north represent the areas of highest interaction for migration during season three (September to December), and season two (May to August) for internesting. The results of this research highlight that number of small boats activity represents another important stressor for important aggregation zones for sea turtle populations. Keywords: Turtles, interaction, vessels, track, marine.

A Study on the Ephemerality of Public Space in Traditional Village from a Cognitive Perspective

Based on the design method of urban and rural planning, we combine the theories and methods of geography and habitat environment disciplines, and introduce the "schema" theory of psychology to construct the cognitive maps of residents and tourists. Using Zishan Village in Hanwang Town, Xuzhou City as an empirical case, we extracted regional characteristics and explored the cognitive evaluation of residents and tourists, and analyzed the research data in a qualitative and quantitative way. The satellite tracking 3D track function was used to record the travel routes and shooting points of the sample population, and the collected data were overlaid to analyze the overlap of the routes and shooting points, so as to derive the interest points of residents and tourists. The data were summarized in tabular form and imported into SPSS for cross-tabulation analysis and chi-square test. Questionnaire interviews were used to collect the personal feelings of residents and tourists from a qualitative perspective. The cognitive maps of residents and tourists were constructed and their differences were explored to visualize the regional characteristics of traditional village public space and to identify effective landscape design and public space construction, which can provide reference and basis for village construction.

Mars thermal inertia and surface temperatures by the Mars Climate Sounder

Over the last 16 years, the Mars Climate Sounder (MCS) onboard the Mars Reconnaissance Orbiter (MRO) has acquired a large body of surface observations at visible and thermal infrared wavelengths. Primary differentiators between the MCS record and other surface datasets include mission duration, regular global coverage, and high emission angles associated with most observations. These data have been analyzed to generate a global median apparent thermal inertia map that smooths out artificial spatial variability (i.e., streaking along orbital ground tracks) common in other maps. At mid and low latitudes, high emission angle observations yield similar nighttime thermal inertia values compared to nadir observations, even if grazing angles should favor vertically rough materials oriented towards MCS (i.e., material poking out of the ground, presumably associated with high thermal inertia rocks and scarps). This result independently confirms that fines control the Martian thermal inertia, not rocks, and also suggests that most rock and bedrock exposures should be characterized by low aspect ratios (i.e., appear platy or flat, regardless of subsurface shape). Selected global temperature maps are also presented. They show the influence of polar processes, the latitudinal distribution of exposed ices, and physical properties of the Martian regolith on surface temperatures. Temperature controls at regional and global scales include the variation of insolation with season and latitude, atmospheric composition, global circulation, the presence of snow precipitations, and various regolith properties (i.e., albedo and thermal inertia).

First-ever satellite tracking of Black Terns (Chlidonias niger): Insights into home range and habitat selection.

Understanding animal movement across the annual cycle is critical for developing appropriate conservation plans, but the large size and high cost of tracking devices can limit the spatial and temporal resolution at which movement data can be collected, especially for small avian species. Furthermore, for species with low breeding site fidelity, the ability to obtain tracking data from small, archival tags is hindered by low recapture rates. We deployed satellite tracking devices on four adult Black Terns (Chlidonias niger), a declining waterbird with low site fidelity, to examine space use and selection of resources within individual breeding home ranges. We also provide a preliminary assessment of habitat use during fall stopover. We found that home ranges were extensive (mean 283.7 km2) and distances travelled from the nest substantially larger (up to 35 km) than previously thought (~2.5 km). Terns showed selection for wetlands and open water on the breeding grounds, but also showed selection for developed areas. This may reflect humans selecting similar landscape features for recreation and development as terns, and suggests that terns can tolerate the light degree of development (e.g. cottages, boat launches, etc.) within our study area. Despite a small sample size, this is the first study to track individual Black Terns at a high resolution with implications for conservation and wetland management practices relevant to the spatial scales at which habitat is used by the species.

First satellite tracking of a free-ranging spotted seal (Phoca largha) from the Baengnyeongdo Island

First satellite tracking of a free-ranging spotted seal (Phoca largha) from the Baengnyeongdo Island

A Tutorial on Retroreflectors and Arrays Used in Satellite and Lunar Laser Ranging

The present paper discusses the basics of retroreflector theory and the manner in which they are combined in arrays to service the laser tracking of artificial satellites and the Moon. We begin with a discussion of the relative advantages and disadvantages of solid versus hollow cube corners and the functional dependence of their optical cross-sections and far-field patterns on cube diameter. Because of velocity aberration effects, the design of an array for a particular space mission depends on many factors, including the desired range accuracy and the satellite’s orbital altitude, velocity, and pass geometry relative to the tracking station. This generally requires the individual retroreflectors in the array to be “spoiled” by perturbing one or more of the 90-degree angles that define a perfect cube corner, or alternatively, by adding a curved surface to a hollow cube. In order to obtain adequate return signal strengths from all points along the satellite path, the rotational orientation of the retroreflectors within the array may need to be varied or “clocked”. Possible approaches to developing millimeter-accuracy arrays with both large cross-sections and ultrashort satellite signatures are discussed, as are new designs proposed to replace aging reflectors on the Moon. Finally, we briefly discuss methods for laser ranging beyond the Moon.

Conservation of Bewick’s swans (Cygnus columbianus bewickii): Insights from the identification of critical stopover sites and migration corridors

Migratory birds face diverse threats during migration. Critical stopover sites (CSSs) are essential refueling and resting sites for migratory birds that ensure their complete migration and survival. Therefore, identifying bird migration patterns, routes, and critical habitats is vital for conservation. From 2018–2022, we deployed satellite tracking devices on 30 Bewick’s swans (Cygnus columbianus bewickii) wintering in China to determine their migration routes. Using a dynamic Brownian bridge movement model, we identified migration corridors, core movement areas, and CSSs for Bewick’s swans. Combining protected area databases and human settlement types, we further assessed the swans’ conservation status and human impacts on CSSs. The results showed that Bewick’s swans migrated north from their wintering grounds using one of three routes (west, middle, and east), passing through Mongolia to reach the Russian Arctic (breeding grounds) in spring. They followed similar routes during autumn to return to wintering grounds. We found a new middle route within the East Asian–Australasian Flyway (EAAF) and several northward expanded wintering sites. Our study revealed similarities and differences in the spring and autumn migrations, with longer stopover durations in spring due to migration strategies and ice conditions. Moreover, our findings identified the Inner Mongolia region, the Songnen Plain, the Bohai Rim of China, and the main streams of the Lena River and the Ob River of Russia as CSSs for Bewick’s swans. However, the conservation status of the CSSs was relatively low; and the situation was more severe in spring than in autumn, only 4.3% of the total area was protected, likely due to the distribution of farmland and urban areas. Specifically, 14.3% of the CSSs in China were in urban areas during spring, while in Mongolia and Russia this figure was less than 1%. Therefore, it is necessary to balance waterbird conservation with sustainable agriculture and urban development. This research contributes to our understanding of the migratory ecology of Bewick’s swans wintering in China. The identified migration corridors and CSSs are crucial for the future conservation of swans along the EAAF.

Dispersal of juvenile Barrow’s goldeneyes (Bucephala islandica) mirrors that of breeding adults

Barrow’s goldeneyes across western North America have been shown to have a high degree of subpopulation independence using several data types. However, evidence for structured populations based on mitochondrial DNA, band recoveries, and tracking of adults is discordant with evidence from autosomal DNA. We used satellite tracking data from both juveniles and adults marked on natal and breeding grounds, respectively, in British Columbia, Canada to evaluate the hypothesis that male-biased juvenile dispersal maintains genetic panmixia of Pacific Barrow’s goldeneyes otherwise structured by migratory movements and high winter and breeding site fidelity of adults. We found that juvenile males traveled to overwintering sites located within the range of the overwintering sites of juvenile females, adult males, and adult females. Juvenile males migrated at the same time, travelled the same distance when moving between natal and overwintering sites, and had the same winter dispersion as juvenile females. Although juveniles did not travel with attendant females, all juveniles overwintered within the wintering range of adults. We tracked some juveniles into the following spring/summer and even second winter. Prospecting juveniles of both sexes travelled from their wintering grounds to potential breeding sites in the proximity of Riske Creek and within the bounds of the breeding locations used by adults. Juveniles tracked for more than a year also showed relatively high winter site fidelity. Because Barrow’s goldeneyes pair on wintering grounds, our tracking data are not consistent with the hypothesis that male-biased juvenile dispersal explains the genetic structure in the mitochondrial DNA and panmixia in the autosomal DNA of Barrow’s goldeneye. We suggest that uncommon or episodic dispersal of males might be enough to homogenize autosomal DNA but is unlikely to influence demographic population structure relevant to contemporary population management.

Switching threshold event‐triggered critic algorithm for optimal orbit tracking and formation motion

AbstractThis paper deals with the orbit tracking and formation motion problems with optimal energies and reduced computational cost. First, the orbit tracking and formation motion are decomposed into movements in the normal and tangent directions of level orbits, respectively, and simultaneously, the optimal value functions in both directions are defined. Then, to reduce the computational cost, a switching threshold event‐triggered (STET) mechanism is designed. Based on the STET mechanism, the optimal value functions are constructed to evaluate the optimal energies of orbit tracking and formation motion. Critic neural networks are then designed to approximate the optimal value functions, which yield the optimal policies along the normal and tangent directions of desired orbits, that is, a so‐called switching threshold event‐triggered critic algorithm (STET‐C). Theoretical analysis of system convergence is given in detail. Finally, two comparison simulations are given. The former intends to verify the optimal energy of STET‐C compared to the feedback controllers. The latter shows that STET‐C significantly reduces the computational cost in contrast with the non‐triggered actor‐critic algorithm, non‐triggered critic algorithm, and the relative threshold event‐triggered critic algorithm.

Analysis and Implementation of a Satellite Tracking System applied to pets using free software with GPS and GSM technology

The project aims to implement a satellite tracking system for pets, using GSM and GPS technology, free software and a VPS server. An analysis will be carried out to select the best GPS device. In addition, a mobile application will be developed that will allow users to see the geographic location of their pet and place virtual fences to prevent its loss. The application will also include additional options, such as the ability to configure the intensity of satellite tracking, call the device, and access a video tutorial and a menu of pet tips. The VPS server will host and route the satellite tracking software, and the mobile application will allow users to view their pet's location in real time and receive alerts if the pet leaves the geofence boundary. In summary, the project's main goal is to prevent pet loss and provide a useful tool to keep pets healthy and happy.